WorldWideScience

Sample records for biofouling

  1. Applicability of short-term accelerated biofouling studies to predict long-term biofouling accumulation in reverse osmosis membrane systems

    KAUST Repository

    Sanawar, Huma

    2018-02-02

    Biofouling studies addressing biofouling control are mostly executed in short-term studies. It is unclear whether data collected from these experiments are representative for long-term biofouling as occurring in full-scale membrane systems. This study investigated whether short-term biofouling studies accelerated by biodegradable nutrient dosage to feed water were predictive for long-term biofouling development without nutrient dosage. Since the presence of a feed spacer has an strong effect on the degree of biofouling, this study employed six geometrically different feed spacers. Membrane fouling simulators (MFSs) were operated with the same (i) membrane, (ii) feed flow and (iii) feed water, but with feed spacers varying in geometry. For the short-term experiment, biofilm formation was enhanced by nutrient dosage to the MFS feed water, whereas no nutrient dosage was applied in the long-term experiment. Pressure drop development was monitored to characterize the extent of biofouling, while the accumulated viable biomass content at the end of the experimental run was quantified by adenosine triphosphate (ATP) measurements. Impact of feed spacer geometry on biofouling was compared for the short-term and long-term biofouling study. The results of the study revealed that the feed spacers exhibited the same biofouling behavior for (i) the short-term (9-d) study with nutrient dosage and (ii) the long-term (96-d) study without nutrient dosage. For the six different feed spacers, the accumulated viable biomass content (pg ATP.cm) was roughly the same, but the biofouling impact in terms of pressure drop increase in time was significantly different. The biofouling impact ranking of the six feed spacers was the same for the short-term and long-term biofouling studies. Therefore, it can be concluded that short-term accelerated biofouling studies in MFSs are a representative and suitable approach for the prediction of biofouling in membrane filtration systems after long

  2. Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators

    KAUST Repository

    Siddiqui, Amber

    2016-12-22

    Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems. The objective of this study was to evaluate the biofouling potential of two commercially available reference feed spacers and four modified feed spacers. The spacers were compared on hydraulic characterization and in biofouling studies with membrane fouling simulators (MFSs). The virgin feed spacer was characterized hydraulically by their resistance, measured in terms of feed channel pressure drop, performed by operating MFSs at varying feed water flow rates. Short-term (9 days) biofouling studies were carried out with nutrient dosage to the MFS feed water to accelerate the biofouling rate. Long-term (96 days) biofouling studies were done without nutrient dosage to the MFS feed water. Feed channel pressure drop was monitored and accumulation of active biomass was quantified by adenosine tri phosphate (ATP) determination. The six feed spacers were ranked on pressure drop (hydraulic characterization) and on biofouling impact (biofouling studies). Significantly different trends in hydraulic resistance and biofouling impact for the six feed spacers were observed. The same ranking for biofouling impact on the feed spacers was found for the (i) short-term biofouling study with nutrient dosage and the (ii) long-term biofouling study without nutrient dosage. The ranking for hydraulic resistance for six virgin feed spacers differed significantly from the ranking of the biofouling impact, indicating that hydraulic resistance of clean feed spacers does not predict the hydraulic resistance of biofouled feed spacers. Better geometric design of feed spacers can be a suitable approach to minimize impact of biofouling in spiral wound membrane systems.

  3. The increase of biofouling in cooling water; Microweb reduceert biofouling in koelwater

    Energy Technology Data Exchange (ETDEWEB)

    De Boer, B.; Overgaauw, C. (eds.)

    2007-04-15

    A method to prevent biofouling in cooling water systems is to remove materials which stimulate the growth of micro-organisms. Such materials are in particular biodegradable materials as amino acids, carbon hydrates and volatile fatty acids. The Dutch research institute TNO carries out research on biofiltration by means of which biofouling and other forms of pollution can be controlled or prevented. TNO developed a biofilter for this purpose: MICROWEB. [Dutch] Een preventieve methode om biofouling in koelwatersystemen te beheersen is het verwijderen van stoffen die de groei van micro-organismen bevorderen. Het zijn vooral gemakkelijk biologisch afbreekbare componenten zoals aminozuren, koolhydraten en vluchtige vetzuren die al bij zeer lage concentraties (vanaf enkele microgrammen per liter), biologische groei stimuleren. TNO onderzoekt op welke wijze biofiltratie een positieve bijdrage levert aan het beheersen van biofouling en andere vormen van vervuiling. TNO ontwikkelde hiervoor een biofilter onder de naam MICROWEB.

  4. Targeting N-acyl-homoserine-lactones to mitigate membrane biofouling based on quorum sensing using a biofouling reducer.

    Science.gov (United States)

    Siddiqui, Muhammad Faisal; Sakinah, Mimi; Singh, Lakhveer; Zularisam, A W

    2012-10-31

    Exploring novel biological anti-quorum sensing (QS) agents to control membrane biofouling is of great worth in order to allow sustainable performance of membrane bioreactors (MBRs) for wastewater treatment. In recent studies, QS inhibitors have provided evidence of alternative route to control membrane biofouling. This study investigated the role of Piper betle extract (PBE) as an anti-QS agent to mitigate membrane biofouling. Results demonstrated the occurrence of the N-acyl-homoserine-lactone (AHL) autoinducers (AIs), correlate QS activity and membrane biofouling mitigation. The AIs production in bioreactor was confirmed using an indicator strain Agrobacterium tumefaciens (NTL4) harboring plasmid pZLR4. Moreover, three different AHLs were found in biocake using thin layer chromatographic analysis. An increase in extracellular polymeric substances (EPS) and transmembrane pressure (TMP) was observed with AHL activity of the biocake during continuous MBR operation, which shows that membrane biofouling was in close relationship with QS activity. PBE was verified to mitigate membrane biofouling via inhibiting AIs production. SEM analysis further confirmed the effect of PBE on EPS and biofilm formation. These results exhibited that PBE could be a novel agent to target AIs for mitigation of membrane biofouling. Further work can be carried out to purify the active compound of Piper betle extract to target the QS to mitigate membrane biofouling. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Potential biocontrol agents for biofouling on artificial structures.

    Science.gov (United States)

    Atalah, Javier; Newcombe, Emma M; Hopkins, Grant A; Forrest, Barrie M

    2014-09-01

    The accumulation of biofouling on coastal structures can lead to operational impacts and may harbour problematic organisms, including non-indigenous species. Benthic predators and grazers that can supress biofouling, and which are able to be artificially enhanced, have potential value as augmentative biocontrol agents. The ability of New Zealand native invertebrates to control biofouling on marina pontoons and wharf piles was tested. Caging experiments evaluated the ability of biocontrol to mitigate established biofouling, and to prevent fouling accumulation on defouled surfaces. On pontoons, the gastropods Haliotis iris and Cookia sulcata reduced established biofouling cover by >55% and largely prevented the accumulation of new biofouling over three months. On wharf piles C. sulcata removed 65% of biofouling biomass and reduced its cover by 73%. C. sulcata also had better retention and survival rates than other agents. Augmentative biocontrol has the potential to be an effective method to mitigate biofouling on marine structures.

  6. Biofouling Control in Cooling Water

    Directory of Open Access Journals (Sweden)

    T. Reg Bott

    2009-01-01

    Full Text Available An important aspect of environmental engineering is the control of greenhouse gas emissions. Fossil fuel-fired power stations, for instance, represent a substantial contribution to this problem. Unless suitable steps are taken the accumulation of microbial deposits (biofouling on the cooling water side of the steam condensers can reduce their efficiency and in consequence, the overall efficiency of power production, with an attendant increase in fuel consumption and hence CO2 production. Biofouling control, therefore, is extremely important and can be exercised by chemical or physical techniques or a combination of both. The paper gives some examples of the effectiveness of different approaches to biofouling control.

  7. Biofouling in reverse osmosis: phenomena, monitoring, controlling and remediation

    Science.gov (United States)

    Maddah, Hisham; Chogle, Aman

    2017-10-01

    This paper is a comprehensive review of biofouling in reverse osmosis modules where we have discussed the mechanism of biofouling. Water crisis is an issue of pandemic concern because of the steady rise in demand of drinking water. Overcoming biofouling is vital since we need to optimize expenses and quality of potable water production. Various kinds of microorganisms responsible for biofouling have been identified to develop better understanding of their attacking behavior enabling us to encounter the problem. Both primitive and advanced detection techniques have been studied for the monitoring of biofilm development on reverse osmosis membranes. Biofouling has a negative impact on membrane life as well as permeate flux and quality. Thus, a mathematical model has been presented for the calculation of normalized permeate flux for evaluating the extent of biofouling. It is concluded that biofouling can be controlled by the application of several physical and chemical remediation techniques.

  8. Short-term adhesion and long-term biofouling testing of polydopamine and poly(ethylene glycol) surface modifications of membranes and feed spacers for biofouling control

    KAUST Repository

    Miller, Daniel J.

    2012-08-01

    Ultrafiltration, nanofiltration membranes and feed spacers were hydrophilized with polydopamine and polydopamine- g-poly(ethylene glycol) surface coatings. The fouling propensity of modified and unmodified membranes was evaluated by short-term batch protein and bacterial adhesion tests. The fouling propensity of modified and unmodified membranes and spacers was evaluated by continuous biofouling experiments in a membrane fouling simulator. The goals of the study were: 1) to determine the effectiveness of polydopamine and polydopamine- g-poly(ethylene glycol) membrane coatings for biofouling control and 2) to compare techniques commonly used in assessment of membrane biofouling propensity with biofouling experiments under practical conditions. Short-term adhesion tests were carried out under static, no-flow conditions for 1 h using bovine serum albumin, a common model globular protein, and Pseudomonas aeruginosa, a common model Gram-negative bacterium. Biofouling tests were performed in a membrane fouling simulator (MFS) for several days under flow conditions similar to those encountered in industrial modules with the autochthonous drinking water population and acetate dosage as organic substrate. Polydopamine- and polydopamine- g-poly(ethylene glycol)-modified membranes showed significantly reduced adhesion of bovine serum albumin and P. aeruginosa in the short-term adhesion tests, but no reduction of biofouling was observed during longer biofouling experiments with modified membranes and spacers. These results demonstrate that short-term batch adhesion experiments using model proteins or bacteria under static conditions are not indicative of biofouling, while continuous biofouling experiments showed that membrane surface modification by polydopamine and polydopamine- g-poly(ethylene glycol) is not effective for biofouling control. © 2012 Elsevier Ltd.

  9. Biofouling protection for marine environmental sensors

    Directory of Open Access Journals (Sweden)

    L. Delauney

    2010-05-01

    Full Text Available These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week.

    Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months.

    This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques.

  10. Mechanisms and methods for biofouling prevention via aeration

    Science.gov (United States)

    Dickenson, Natasha; Henoch, Charles; Belden, Jesse

    2013-11-01

    Biofouling is a major problem for the Navy and marine industries, with significant economic and ecological consequences. Specifically, biofouling on immersed hull surfaces generates increased drag and thus requires increased fuel consumption to maintain speed. Considerable effort has been spent developing techniques to prevent and control biofouling, but with limited success. Control methods that have proven to be effective are costly, time consuming, or negatively affect the environment. Recently, aeration via bubble injection along submerged surfaces has been shown to achieve long-lasting antifouling effects, and is the only effective non-toxic method available. An understanding of the basic mechanisms by which bubble-induced flow impedes biofouling is lacking, but is essential for the design of large-scale systems. We present results from an experimental investigation of several bubble induced flow fields over an inclined plate with simultaneous measurements of the fluid velocity and bubble characteristics using Digital article Image Velocimetry and high speed digital video. Trajectories of representative larval organisms are also resolved and linked with the flow field measurements to determine the mechanisms responsible for biofouling prevention.

  11. New approaches to characterizing and understanding biofouling of spiral wound membrane systems

    KAUST Repository

    van Loosdrecht, Mark C.M.

    2012-06-01

    Historically, biofouling research on spiral wound membrane systems is typically problem solving oriented. Membrane modules are studied as black box systems, investigated by autopsies. Biofouling is not a simple process. Many factors influence each other in a non-linear fashion. These features make biofouling a subject which is not easy to study using a fundamental scientific approach. Nevertheless to solve or minimize the negative impacts of biofouling, a clear understanding of the interacting basic principles is needed. Recent research into microbiological characterizing of biofouling, small scale test units, application of in situ visualization methods, and model approaches allow such an integrated study of biofouling. © IWA Publishing 2012.

  12. New approaches to characterizing and understanding biofouling of spiral wound membrane systems

    KAUST Repository

    van Loosdrecht, Mark C.M.; Bereschenko, Ludmilla A.; Radu, Andrea I.; Kruithof, Joop C.; Picioreanu, Cristian; Johns, Michael L.; Vrouwenvelder, Johannes S.

    2012-01-01

    Historically, biofouling research on spiral wound membrane systems is typically problem solving oriented. Membrane modules are studied as black box systems, investigated by autopsies. Biofouling is not a simple process. Many factors influence each other in a non-linear fashion. These features make biofouling a subject which is not easy to study using a fundamental scientific approach. Nevertheless to solve or minimize the negative impacts of biofouling, a clear understanding of the interacting basic principles is needed. Recent research into microbiological characterizing of biofouling, small scale test units, application of in situ visualization methods, and model approaches allow such an integrated study of biofouling. © IWA Publishing 2012.

  13. Study of electroplated silver-palladium biofouling inhibiting coating

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Hilbert, Lisbeth Rischel; Møller, Per

    The undesired microbial and biofilm adhesions on the surfaces of food industrial facilities, water supply systems and etc. are so called as “biofouling”. Biofouling can cause many undesirable effects. Until now for solving biofouling, there are few non-toxic inhibiting treatments. In this study, ...

  14. Early non-destructive biofouling detection and spatial distribution: Application of oxygen sensing optodes

    KAUST Repository

    Farhat, Nadia

    2015-06-11

    Biofouling is a serious problem in reverse osmosis/nanofiltration (RO/NF) applications, reducing membrane performance. Early detection of biofouling plays an essential role in an adequate anti-biofouling strategy. Presently, fouling of membrane filtration systems is mainly determined by measuring changes in pressure drop, which is not exclusively linked to biofouling. Non-destructive imaging of oxygen concentrations (i) is specific for biological activity of biofilms and (ii) may enable earlier detection of biofilm accumulation than pressure drop. The objective of this study was to test whether transparent luminescent planar O2 optodes, in combination with a simple imaging system, can be used for early non-destructive biofouling detection. This biofouling detection is done by mapping the two-dimensional distribution of O2 concentrations and O2 decrease rates inside a membrane fouling simulator (MFS). Results show that at an early stage, biofouling development was detected by the oxygen sensing optodes while no significant increase in pressure drop was yet observed. Additionally, optodes could detect spatial heterogeneities in biofouling distribution at a micro scale. Biofilm development started mainly at the feed spacer crossings. The spatial and quantitative information on biological activity will lead to better understanding of the biofouling processes, contributing to the development of more effective biofouling control strategies.

  15. Study of electroplated silver-palladium biofouling inhibiting coating

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Hilbert, Lisbeth Rischel; Schroll, Casper

    2008-01-01

    Biofouling can cause many undesirable effects in industrial and medical settings. In this study, a new biofouling inhibiting Ag-Pd surface was designed to form an inhibiting effect by itself. This design was based on silver combined with nobler palladium, both with catalytic properties. Owing to ...

  16. Biofouling of power-plant service systems by Corbicula

    International Nuclear Information System (INIS)

    Page, T.L.; Neitzel, D.A.; Simmons, M.A.; Hayes, P.F.

    1983-08-01

    Corbicula sp. foul the service water systems at nuclear power plants because the environment within these systems is compatible with the ecological requirements of the species. To reduce Corbicula fouling, components of service water systems and operating procedures that enhance the potential for fouling need to be identified. Factors important in mediating biofouling of service water systems appear to be screening potential, minimum and maximum velocities and the operational procedures employed during power plant biofoulant control and downtime. These conclusions are based on the results of a categorical model we used to correlate information from power plants with that on Corbicula life history. Power plant parameters in the model include temperature, dissolved oxygen concentration, screen and strainer size, maximum and minimum velocities, and elements of the biofouling control procedures. Parameters for Corbicula include tolerances to temperature, dissolved oxygen, biofouling control chemicals, velocity preferences, and optimal temperatures for each life stage and behavior. 13 references, 5 figures

  17. Linking ceragenins to water-treatment membranes to minimize biofouling.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Altman, Susan Jeanne; Feng, Yanshu (Brigham Young University, Provo, Utah); Savage, Paul B. (Brigham Young University, Provo, Utah); Pollard, Jacob (Brigham Young University, Provo, Utah); Branda, Steven S.; Goeres, Darla (Montana State University, Bozeman, MT); Buckingham-Meyer, Kelli (Montana State University, Bozeman, MT); Stafslien, Shane (North Dakota State University, Fargo, ND); Marry, Christopher; Jones, Howland D. T.; Lichtenberger, Alyssa; Kirk, Matthew F.; McGrath, Lucas K. (LMATA, Albuquerque, NM)

    2012-01-01

    Ceragenins were used to create biofouling resistant water-treatment membranes. Ceragenins are synthetically produced antimicrobial peptide mimics that display broad-spectrum bactericidal activity. While ceragenins have been used on bio-medical devices, use of ceragenins on water-treatment membranes is novel. Biofouling impacts membrane separation processes for many industrial applications such as desalination, waste-water treatment, oil and gas extraction, and power generation. Biofouling results in a loss of permeate flux and increase in energy use. Creation of biofouling resistant membranes will assist in creation of clean water with lower energy usage and energy with lower water usage. Five methods of attaching three different ceragenin molecules were conducted and tested. Biofouling reduction was observed in the majority of the tests, indicating the ceragenins are a viable solution to biofouling on water treatment membranes. Silane direct attachment appears to be the most promising attachment method if a high concentration of CSA-121a is used. Additional refinement of the attachment methods are needed in order to achieve our goal of several log-reduction in biofilm cell density without impacting the membrane flux. Concurrently, biofilm forming bacteria were isolated from source waters relevant for water treatment: wastewater, agricultural drainage, river water, seawater, and brackish groundwater. These isolates can be used for future testing of methods to control biofouling. Once isolated, the ability of the isolates to grow biofilms was tested with high-throughput multiwell methods. Based on these tests, the following species were selected for further testing in tube reactors and CDC reactors: Pseudomonas ssp. (wastewater, agricultural drainage, and Colorado River water), Nocardia coeliaca or Rhodococcus spp. (wastewater), Pseudomonas fluorescens and Hydrogenophaga palleronii (agricultural drainage), Sulfitobacter donghicola, Rhodococcus fascians, Rhodobacter

  18. A Wave Glider for Studies of Biofouling and Ocean Productivity

    Science.gov (United States)

    2017-11-07

    Report: A Wave Glider for Studies of Biofouling and Ocean Productivity The views, opinions and/or findings contained in this report are those of the...Biofouling and Ocean Productivity Report Term: 0-Other Email: john.breier@utrgv.edu Distribution Statement: 1-Approved for public release; distribution is...sensors, and engineered test surfaces was procured to study controls on ocean productivity , plankton distribution, larval settling, and biofouling. We

  19. Application of DBNPA dosage for biofouling control in spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber

    2017-05-30

    Biocides may be used to control biofouling in spiral-wound reverse osmosis (RO) and nanofiltration (NF) systems. The objective of this study was to investigate the effect of biocide 2,2-dibromo-3-ni-trilopropionamide (DBNPA) dosage on biofouling control. Preventive biofouling control was studied applying a continuous dosage of substrate (0.5 mg/L) and DBNPA (1 mg/L). Curative biofouling control was studied on pre-grown biofilms, once again applying a continuous dosage of substrate (0.5 mg acetate C/L) and DBNPA (1 and 20 mg/L). Biofouling studies were performed in membrane fouling simulators (MFSs) supplied with biodegradable substrate and DBNPA. The pressure drop was monitored in time and at the end of the study, the accumulated biomass in MFS was quantified by adenosine triphosphate (ATP) and total organic carbon (TOC) analysis. Continuous dosage of DBNPA (1 mg/L) prevented pressure drop increase and biofilm accumulation in the MFSs during a run time of 7 d, showing that biofouling can be managed by preventive DBNPA dosage. For biofouled systems, continuous dosage of DBNPA (1 and 20 mg/L) inactivated the accumulated biomass but did not restore the original pressure drop and did not remove the accumulated inactive cells and extracellular polymeric substances (EPS), indicating DBNPA dosage is not suitable for curative biofouling control.

  20. Biofouling and biocorrosion in industrial water systems.

    Science.gov (United States)

    Coetser, S E; Cloete, T E

    2005-01-01

    Corrosion associated with microorganisms has been recognized for over 50 years and yet the study of microbiologically influenced corrosion (MIC) is relatively new. MIC can occur in diverse environments and is not limited to aqueous corrosion under submerged conditions, but also takes place in humid atmospheres. Biofouling of industrial water systems is the phenomenon whereby surfaces in contact with water are colonized by microorganisms, which are ubiquitous in our environment. However, the economic implications of biofouling in industrial water systems are much greater than many people realize. In a survey conducted by the National Association of Corrosion Engineers of the United States ten years ago, it was found that many corrosion engineer did not accept the role of bacteria in corrosion, and many of then that did, could not recognize and mitigate the problem. Biofouling can be described in terms of its effects on processes and products such as material degradation (bio-corossion), product contamination, mechanical blockages, and impedance of heat transfer. Microorganisms distinguish themselves from other industrial water contaminants by their ability to utilize available nutrient sources, reproduce, and generate intra- and extracellular organic and inorganic substances in water. A sound understanding of the molecular and physiological activities of the microorganisms involved is necessary before strategies for the long term control of biofouling can be format. Traditional water treatment strategies however, have largely failed to address those factors that promote biofouling activities and lead to biocorrosion. Some of the major developments in recent years have been a redefinition of biofilm architecture and the realization that MIC of metals can be best understood as biomineralization.

  1. Biofouling and its prevention in condenser tubes

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, K; Minamoto, K; Kyohara, S [Kobe Steel Ltd. (Japan). Central Research and Development Lab.

    1979-04-01

    In this paper, biofouling in condenser tubes and methods of prevention are described. Biofouling has a tendency to occur in tubes under lower velocity of sea water, and fouling organisms, if allowed to build up, cannot be removed by ordinary nylon brush cleaning. As the results of our investigation, it was concluded that sponge ball cleaning should be employed when the condenser is operated under lower velocity of sea water in the bacteria breeding season.

  2. Pathogenic Vibrio parahaemolyticus isolated from biofouling on commercial vessels and harbor structures.

    Science.gov (United States)

    Revilla-Castellanos, Valeria J; Guerrero, Abraham; Gomez-Gil, Bruno; Navarro-Barrón, Erick; Lizárraga-Partida, Marcial L

    2015-01-01

    Ballast water is a significant vector of microbial dissemination; however, biofouling on commercial vessel hulls has been poorly studied with regard to pathogenic bacteria transport. Biofouling on three commercial vessels and seven port structures in Ensenada, Baja California, Mexico, was examined by qPCR to identify and quantify Vibrio parahaemolyticus, a worldwide recognized food-borne human pathogen. Pathogenic variants (trh+, tdh+) of V. parahaemolyticus were detected in biofouling homogenates samples from several docks in Ensenada and on the hulls of ships with Japanese and South Korean homeports, but not in reference sampling stations. A total of 26 tdh+ V. parahaemolyticus colonies and 1 ORF8+/O3:K6 strain were also isolated from enriched biofouling homogenate samples confirming the qPCR analysis. Our results suggest that biofouling is an important reservoir of pathogenic vibrios. Thus, ship biofouling might be an overlooked vector with regard to the dissemination of pathogens, primarily pathogenic V. parahaemolyticus.

  3. PROBLEMS OF BIOFOULING ON FISH–CAGE NETS IN AQUACULTURE

    Directory of Open Access Journals (Sweden)

    Merica Slišković

    2002-09-01

    Full Text Available Biofouling on fish–cage netting is a serious technical and economical problem to aquaculture worldwide. Compensation for the effects of biofouling must be included in cage system design and planning, as fouling can dramatically increase both weight and drag. Settlements of sessile plants and animals, with accumulation of the detritus diminish the size of mesh and can rapidly occlude mesh. Negative effect of smaller mesh size is changing in water flow trough the cages. Biofouling problems necessitating purchase of a second sets of nets or more, and frequent cleaning and changing of biofouling. Changing and cleaning frequency depend on many factors such as: location of cages (near the coast or off shore, productivity of that location, time of the year, time period in which the cages are placed on that location (cause of loading of phosphorus and nitrogen from the unconsumed food in the sediment. Net changing and cleaning procedures are labor and capital intensive. Process of the cleaning of the nets is inadequate, especially when there isnžt adequate equipment available as it is case in smaller aquaculture industry. Chemical control of biofouling e. g. use of antifoulants is questioningly cause of their possible negative effects on breeding species and environment.

  4. Review on strategies for biofouling mitigation in spiral wound membrane systems

    KAUST Repository

    Bucs, Szilard

    2018-02-01

    Because of the uneven distribution of fresh water in time and space, a large number of regions are experiencing water scarcity and stress. Membrane based desalination technologies have the potential to solve the fresh water crisis in coastal areas. However, in many cases membrane performance is restricted by biofouling. The objective of this review is to provide an overview on the state of the art strategies to control biofouling in spiral wound reverse osmosis membrane systems and point to possible future research directions. A critical review on biofouling control strategies such as feed water pre-treatment, membrane surface modification, feed spacer geometry optimization and hydrodynamics in spiral wound membrane systems is presented. In conclusion, biofouling cannot be avoided in the long run, and thus biofouling control strategies should focus on delaying the biofilm formation, reducing its impact on membrane performance and enhancing biofilm removal by advanced cleaning strategies. Therefore, future studies should aim on: (i) biofilm structural characterization; (ii) understanding to what extent biofilm properties affect membrane filtration performance, and (iii) developing methods to engineer biofilm properties such that biofouling would have only a low or delayed impact on the filtration process and accumulated biomass can be easily removed.

  5. Fouling in your own nest: vessel noise increases biofouling.

    Science.gov (United States)

    Stanley, Jenni A; Wilkens, Serena L; Jeffs, Andrew G

    2014-01-01

    Globally billions of dollars are spent each year on attempting to reduce marine biofouling on commercial vessels, largely because it results in higher fuel costs due to increased hydrodynamic drag. Biofouling has been long assumed to be primarily due to the availability of vacant space on the surface of the hull. Here, it is shown that the addition of the noise emitted through a vessel's hull in port increases the settlement and growth of biofouling organisms within four weeks of clean surfaces being placed in the sea. More than twice as many bryozoans, oysters, calcareous tube worms and barnacles settled and established on surfaces with vessel noise compared to those without. Likewise, individuals from three species grew significantly larger in size in the presence of vessel noise. The results demonstrate that vessel noise in port is promoting biofouling on hulls and that underwater sound plays a much wider ecological role in the marine environment than was previously considered possible.

  6. Microbial speciation and biofouling potential of cooling water used by Ontario Hydro

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-02-01

    The cooling water composition and microbial components of biofilms attached to stainless steel wafers submerged in three lake water types were evaluated to determine whether their biofouling potential differed in a predictable manner. The composition of the lake waters was different which affected biofilm composition, where the predominance of specific microbial groups varied between test systems and with time. Some prediction of biofouling potential was possible, and it was concluded that the cooling water in the vicinity of Bruce NGS had the lowest biofouling potential whereas greater biofouling could be expected in the Pickering and Nanticoke stations

  7. Numerical study on the hydrodynamic characteristics of biofouled full-scale net cage

    Science.gov (United States)

    Bi, Chun-wei; Zhao, Yun-peng; Dong, Guo-hai

    2015-06-01

    The effect of biofouling on the hydrodynamic characteristics of the net cage is of particular interest as biofouled nettings can significantly reduce flow of well-oxygenated water reaching the stocked fish. For computational efficiency, the porous-media fluid model is proposed to simulate flow through the biofouled plane net and full-scale net cage. The porous coefficients of the porous-media fluid model can be determined from the quadratic-function relationship between the hydrodynamic forces on a plane net and the flow velocity using the least squares method. In this study, drag forces on and flow fields around five plane nets with different levels of biofouling are calculated by use of the proposed model. The numerical results are compared with the experimental data of Swift et al. (2006) and the effectiveness of the numerical model is presented. On that basis, flow through full-scale net cages with the same level of biofouling as the tested plane nets are modeled. The flow fields inside and around biofouled net cages are analyzed and the drag force acting on a net cage is estimated by a control volume analysis method. According to the numerical results, empirical formulas of reduction in flow velocity and load on a net cage are derived as function of drag coefficient of the corresponding biofouled netting.

  8. Biofouling of various metal oxides in marine environment

    Science.gov (United States)

    Kougo, T.; Kuroda, D.; Wada, N.; Ikegai, H.; Kanematsu, H.

    2012-03-01

    Biofouling has induced serious problems in various industrial fields such as marine structures, bio materials, microbially induced corrosion (MIC) etc. The effects of various metals on biofouling have been investigated so far and the mechanism has been clarified to some extent(1,2), and we proposed that Fe ion attracted lots of bacteria and formed biofilm very easily(3). In this study, we investigated the possibility for biofouling of Pseudomonas aeruginosa on various metal oxides such as Fe2O3, TiO2, WO3, AgO, Cr2O3 etc. And in addition of such a model experiment on laboratory scale, they were immersed into actual sea water as well as artificial sea water. As for the preparation of metal oxides, commercial oxide powders were used as starting material and those whose particle sizes were under 100 micrometers were formed into pellets by a press. Some of them were heated to 700 °C and sintered for 10 hours at the temperatures. After the calcinations, they were immersed into the culture of P. aeruginosa at 35 °C in about one week. After the immersion, they were taken out of the culture and the biofouling behaviors were observed by optical microscopy, low pressure scanning electron microscopy (low pressure SEM) etc. Biofouling is generally classified into several steps. Firstly, conditioning films composed of organic matters were formed on specimens. Then bacterial were attached to the specimen's surfaces, seeking for conditioning films as nutrition. Then bacteria formed biofilm on the specimens. In marine environment, more larger living matters such as shells etc would be attached to biofilms. However, in the culture media, only biofilms were formed.

  9. Bio-fouling and its control in the cooling water system of PFBR

    International Nuclear Information System (INIS)

    Satpathy, K.K.; Kannan, S.E.

    2004-06-01

    This report gives an overview of the bio-fouling problems that could be visualized in the different sections of the cooling system of PFBR, which is based on the experience observed at MAPS as well as from the experience of some of the work carried out at Kalpakkam. International as well as the MAPS practices of bio-fouling control are discussed. Based on these, an appropriate method for bio-fouling control is suggested. In addition, a few time bound, field, as well as laboratory experiments are proposed to be carried out, for deciding precise and accurate method of bio-fouling control for PFBR cooling water system. (author)

  10. The potential of standard and modified feed spacers for biofouling control

    KAUST Repository

    Araú jo, Paula A.; Kruithof, Joop C.; van Loosdrecht, Mark C.M.; Vrouwenvelder, Johannes S.

    2012-01-01

    The impact of feed spacers on initial feed channel pressure (FCP) drop, FCP increase and biomass accumulation has been studied in membrane fouling simulators using feed spacers applied in commercially available nanofiltration and reverse osmosis spiral wound membrane modules. All spacers had a similar geometry.Our studies showed that biofouling was not prevented by (i) variation of spacer thickness, (ii) feed spacer orientation, (iii) feed spacer coating with silver, copper or gold and (iv) using a biostatic feed spacer. At constant feed flow, a lower FCP and FCP increase were observed for a thicker feed spacer. At constant linear flow velocity, roughly the same FCP development and biomass accumulation were found irrespective of the feed spacer thickness: hydrodynamics and substrate load were more important for development and impact of biofouling than the thickness of currently applied spacers. Use of biostatic and metal coated spacers were not effective for biofouling control. The same small reduction of biofouling rate was observed with copper and silver coated spacers as well as uncoated 45° rotated spacers.The studied modified spacers were not effective for biofouling prevention and control. The impact of biofouling on FCP increase was reduced significantly by a lower linear flow velocity, while spacer orientation and spacer thickness in membrane modules had a smaller but still significant effect. © 2012 Elsevier B.V.

  11. The potential of standard and modified feed spacers for biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The impact of feed spacers on initial feed channel pressure (FCP) drop, FCP increase and biomass accumulation has been studied in membrane fouling simulators using feed spacers applied in commercially available nanofiltration and reverse osmosis spiral wound membrane modules. All spacers had a similar geometry.Our studies showed that biofouling was not prevented by (i) variation of spacer thickness, (ii) feed spacer orientation, (iii) feed spacer coating with silver, copper or gold and (iv) using a biostatic feed spacer. At constant feed flow, a lower FCP and FCP increase were observed for a thicker feed spacer. At constant linear flow velocity, roughly the same FCP development and biomass accumulation were found irrespective of the feed spacer thickness: hydrodynamics and substrate load were more important for development and impact of biofouling than the thickness of currently applied spacers. Use of biostatic and metal coated spacers were not effective for biofouling control. The same small reduction of biofouling rate was observed with copper and silver coated spacers as well as uncoated 45° rotated spacers.The studied modified spacers were not effective for biofouling prevention and control. The impact of biofouling on FCP increase was reduced significantly by a lower linear flow velocity, while spacer orientation and spacer thickness in membrane modules had a smaller but still significant effect. © 2012 Elsevier B.V.

  12. Biofouling investigation in membrane filtration systems using Optical Coherence Tomography (OCT)

    KAUST Repository

    Fortunato, Luca

    2017-01-01

    Biofouling represents the main problem in membrane filtration systems. Biofouling arises when the biomass growth negatively impacts the membrane performance parameters (i.e. flux decrease and feed channel pressure drop). Most of the available

  13. In-situ Non-destructive Studies on Biofouling Processes in Reverse Osmosis Membrane Systems

    KAUST Repository

    Farhat, Nadia

    2016-12-01

    Reverse osmosis (RO) and nanofiltration (NF) membrane systems are high-pressure membrane filtration processes that can produce high quality drinking water. Biofouling, biofilm formation that exceeds a certain threshold, is a major problem in spiral wound RO and NF membrane systems resulting in a decline in membrane performance, produced water quality, and quantity. In practice, detection of biofouling is typically done indirectly through measurements of performance decline. Existing direct biofouling detection methods are mainly destructive, such as membrane autopsies, where biofilm samples can be contaminated, damaged and resulting in biofilm structural changes. The objective of this study was to test whether transparent luminescent planar oxygen sensing optodes, in combination with a simple imaging system, can be used for in-situ, non-destructive biofouling characterization. Aspects of the study were early detection of biofouling, biofilm spatial patterning in spacer filled channels, and the effect of feed cross-flow velocity, and feed flow temperature. Oxygen sensing optode imaging was found suitable for studying biofilm processes and gave detailed spatial and quantitative biofilm development information enabling better understanding of the biofouling development process. The outcome of this study attests the importance of in-situ, non-destructive imaging in acquiring detailed knowledge on biofilm development in membrane systems contributing to the development of effective biofouling control strategies.

  14. Anti-biofouling superhydrophobic surface fabricated by picosecond laser texturing of stainless steel

    Science.gov (United States)

    Sun, Ke; Yang, Huan; Xue, Wei; He, An; Zhu, Dehua; Liu, Wenwen; Adeyemi, Kenneth; Cao, Yu

    2018-04-01

    Anti-biofouling technology is based on specifically designed materials and coatings. This is an enduring goal in the maritime industries, such as shipping, offshore oil exploration, and aquaculture. Recently, research of the relationship between wettability and antifouling effectiveness has attracted considerable attention, due to the anti-biofouling properties of the lotus leaf and shark skin. In this study, super-hydrophobic surfaces (SHSs) with controllable periodic structures were fabricated on AISI304 stainless steel by a picosecond laser, and their anti-biofouling performance were investigated by seawater immersion for five weeks in summertime. The results showed that the specimens with SHS demonstrate significant anti-biofouling effect as compared with the bare stainless steel plate. We observed that nearly 50% decrease of the average microbe attachment area ratio (Avg. MAAR) could be obtained. The micro-groove SHS with more abundant hierarchical micro-nano structures showed better anti-biofouling performance than the micro-pit SHS.

  15. International conference on biofouling and materials. Book of abstracts - Programme and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Biofouling is a common, however often unrecognized problem, which causes large costs. Biofouling is the result of biofilm formation, a successful survival strategy of microorganisms. Hence, biofilms occur ubiquitously. Although they are of fundamental importance for purification processes of water, sediment and soils, biofilms can occur in the wrong place and in the wrong time. As a result, billions of dollars are lost every year by biofouling and subsequent consequences, e.g. biocorrosion. These detrimental processes are caused by microorganisms and interfere with the performance, integrity and function of the attacked materials/equipment. This conference, which is largely based on the COST 520-action ''Biofouling and Materials'', aims at an improved understanding of the underlying processes, their recognition, countermeasures, and anti-microbial strategies. Latest information will be presented on case histories, biofouling and biocorrosion monitoring, as well as the use and efficacy of biocides including the relevant European legislation (Biocidal Products Directive). (orig./UKE)

  16. Survival of ship biofouling assemblages during and after voyages to the Canadian Arctic.

    Science.gov (United States)

    Chan, Farrah T; MacIsaac, Hugh J; Bailey, Sarah A

    2016-01-01

    Human-mediated vectors often inadvertently translocate species assemblages to new environments. Examining the dynamics of entrained species assemblages during transport can provide insights into the introduction risk associated with these vectors. Ship biofouling is a major transport vector of nonindigenous species in coastal ecosystems globally, yet its magnitude in the Arctic is poorly understood. To determine whether biofouling organisms on ships can survive passages in Arctic waters, we examined how biofouling assemblage structure changed before, during, and after eight round-trip military voyages from temperate to Arctic ports in Canada. Species richness first decreased (~70% loss) and then recovered (~27% loss compared to the original assemblages), as ships travelled to and from the Arctic, respectively, whereas total abundance typically declined over time (~55% total loss). Biofouling community structure differed significantly before and during Arctic transits as well as between those sampled during and after voyages. Assemblage structure varied across different parts of the hull; however, temporal changes were independent of hull location, suggesting that niche areas did not provide protection for biofouling organisms against adverse conditions in the Arctic. Biofouling algae appear to be more tolerant of transport conditions during Arctic voyages than are mobile, sessile, and sedentary invertebrates. Our results suggest that biofouling assemblages on ships generally have poor survivorship during Arctic voyages. Nonetheless, some potential for transporting nonindigenous species to the Arctic via ship biofouling remains, as at least six taxa new to the Canadian Arctic, including a nonindigenous cirripede, appeared to have survived transits from temperate to Arctic ports.

  17. Biofouling in capillary and spiral wound membranes facilitated by marine algal bloom

    KAUST Repository

    Villacorte, L.O.

    2017-10-11

    Algal-derived organic matter (AOM), particularly transparent exopolymer particles, has been suspected to facilitate biofilm development in membrane systems (e.g., seawater reverse osmosis). This study demonstrates the possible role of AOM on biofouling in membrane systems affected by marine algal blooms. The tendency of AOM from bloom-forming marine algae to adhere to membranes and its ability to enhance biofilm growth were measured using atomic force microscopy, flow cytometry, liquid chromatography and accelerated membrane biofouling experiments. Adhesion force measurements indicate that AOM tends to adhere to clean membranes and even more strongly to AOM-fouled membranes. Batch growth tests illustrate that the capacity of seawater to support bacterial growth can significantly increase with AOM concentration. Biofouling experiments with spiral wound and capillary membranes illustrate that when nutrients availability are not limited in the feed water, a high concentration of AOM – whether in suspension or attached to the membrane – can substantially accelerates biofouling. A significantly lower biofouling rate was observed on membranes exposed to feed water spiked only with AOM or easily biodegradable nutrients. The abovementioned findings indicate that AOM facilitates the onset of membrane biofouling primarily as a conditioning platform and to some extent as a nutrient source for biofilm-forming bacteria.

  18. Biofouling in capillary and spiral wound membranes facilitated by marine algal bloom

    KAUST Repository

    Villacorte, L.O.; Ekowati, Y.; Calix-Ponce, H.N.; Kisielius, V.; Kleijn, J.M.; Vrouwenvelder, Johannes S.; Schippers, J.C.; Kennedy, M.D.

    2017-01-01

    Algal-derived organic matter (AOM), particularly transparent exopolymer particles, has been suspected to facilitate biofilm development in membrane systems (e.g., seawater reverse osmosis). This study demonstrates the possible role of AOM on biofouling in membrane systems affected by marine algal blooms. The tendency of AOM from bloom-forming marine algae to adhere to membranes and its ability to enhance biofilm growth were measured using atomic force microscopy, flow cytometry, liquid chromatography and accelerated membrane biofouling experiments. Adhesion force measurements indicate that AOM tends to adhere to clean membranes and even more strongly to AOM-fouled membranes. Batch growth tests illustrate that the capacity of seawater to support bacterial growth can significantly increase with AOM concentration. Biofouling experiments with spiral wound and capillary membranes illustrate that when nutrients availability are not limited in the feed water, a high concentration of AOM – whether in suspension or attached to the membrane – can substantially accelerates biofouling. A significantly lower biofouling rate was observed on membranes exposed to feed water spiked only with AOM or easily biodegradable nutrients. The abovementioned findings indicate that AOM facilitates the onset of membrane biofouling primarily as a conditioning platform and to some extent as a nutrient source for biofilm-forming bacteria.

  19. Biofouling problems in freshwater cooling systems

    International Nuclear Information System (INIS)

    Rao, T.S.

    2007-01-01

    In aqueous environments, microorganisms (bacteria, algae, fungi etc.,) are attracted towards surfaces, which they readily colonise resulting in the formation of biofilms. The implications of biofouling are energy losses due to increased fluid frictional resistance and increased heat transfer resistance. The temperatures prevalent inside the condenser system provide a favorable environment for the rapid growth of microorganisms. This results in thick slime deposit, which is responsible for heat transfer losses, thereby enhancing aggregation of deposits on the material surface and induces localised corrosion. There have been instances of increased capital costs due to premature replacement of equipment caused by severe under deposit corrosion due to biofouling. Moreover, fouling of service water systems of nuclear power plants is of concern, because it reduces the heat transfer capacity during an emergency or an accident. The growth of microbial films (slimes) a few tens of microns thick, in a condenser tube is sufficient to induce microbiologically influenced corrosion and cause irreparable damage to the condenser tubes and other structural materials. The down time costs to power plant due to condenser fouling and corrosion are quite large. This paper presents the author's experience in biofouling and corrosion problems in various power plants cooled by freshwater. (author)

  20. Microbe-surface interactions in biofouling and biocorrosion processes.

    Science.gov (United States)

    Beech, Iwona B; Sunner, Jan A; Hiraoka, Kenzo

    2005-09-01

    The presence of microorganisms on material surfaces can have a profound effect on materials performance. Surface-associated microbial growth, i.e. a biofilm, is known to instigate biofouling. The presence of biofilms may promote interfacial physico-chemical reactions that are not favored under abiotic conditions. In the case of metallic materials, undesirable changes in material properties due to a biofilm (or a biofouling layer) are referred to as biocorrosion or microbially influenced corrosion (MIC). Biofouling and biocorrosion occur in aquatic and terrestrial habitats varying in nutrient content, temperature, pressure and pH. Interfacial chemistry in such systems reflects a wide variety of physiological activities carried out by diverse microbial populations thriving within biofilms. Biocorrosion can be viewed as a consequence of coupled biological and abiotic electron-transfer reactions, i.e. redox reactions of metals, enabled by microbial ecology. Microbially produced extracellular polymeric substances (EPS), which comprise different macromolecules, mediate initial cell adhesion to the material surface and constitute a biofilm matrix. Despite their unquestionable importance in biofilm development, the extent to which EPS contribute to biocorrosion is not well-understood. This review offers a current perspective on material/microbe interactions pertinent to biocorrosion and biofouling, with EPS as a focal point, while emphasizing the role atomic force spectroscopy and mass spectrometry techniques can play in elucidating such interactions.

  1. Review on strategies for biofouling mitigation in spiral wound membrane systems

    KAUST Repository

    Bucs, Szilard; Farhat, Nadia; Kruithof, Joop C.; Picioreanu, Cristian; van Loosdrecht, Mark C.M.; Vrouwenvelder, Johannes S.

    2018-01-01

    . However, in many cases membrane performance is restricted by biofouling. The objective of this review is to provide an overview on the state of the art strategies to control biofouling in spiral wound reverse osmosis membrane systems and point to possible

  2. Antibiofilm activity of Bacillus pumilus SW9 against initial biofouling on microfiltration membranes.

    Science.gov (United States)

    Zhang, Ying; Yu, Xin; Gong, Song; Ye, Chengsong; Fan, Zihong; Lin, Huirong

    2014-02-01

    Membrane biofouling, resulting from biofilm formation on the membrane, has become the main obstacle hindering wider application of membrane technology. Initial biofouling proves to be crucial which involves early stages of microbial adhesion and biofilm formation. Biological control of microbial attachment seems to be a promising strategy due to its high efficiency and eco-friendliness. The present study investigated the effects of a bacterium Bacillus pumilus SW9 on controlling the initial fouling formed by four target bacterial strains which were pioneer species responsible for biofouling in membrane bioreactors, using microfiltration membranes as the abiotic surfaces. The results suggested that strain SW9 exhibited excellent antibiofilm activity by decreasing the attached biomass of target strains. The production of extracellular polysaccharides and proteins by four target strains was also reduced. A distinct improvement of permeate flux in dead-end filtration systems was achieved when introducing strain SW9 to microfiltration experiments. Scanning electron microscopy and confocal laser scanning microscopy were performed to further ascertain significant changes of the biofouling layers. A link between biofilm inhibition and initial biofouling mitigation was thus provided, suggesting an alternatively potential way to control membrane biofouling through bacterial interactions.

  3. Quantitative biofouling diagnosis in full scale nanofiltration and reverse osmosis installations

    NARCIS (Netherlands)

    Vrouwenvelder, J.S.; Manolarakis, S.A.; van der Hoek, J.P.; van Paassen, J.A.M.; van der Meer, Walterus Gijsbertus Joseph; van Agtmaal, J.M.C.; Prummel, H.D.M.; Kruithof, J.C.; Loosdrecht, M.C.M.

    2008-01-01

    Biofilm accumulation in nanofiltration and reverse osmosis membrane elements results in a relative increase of normalised pressure drop (ΔNPD). However, an increase in ΔNPD is not exclusively linked to biofouling. In order to quantify biofouling, the biomass parameters adenosine triphosphate (ATP),

  4. Characterisation of the biofouling community on a floating wave energy device.

    Science.gov (United States)

    Nall, Christopher R; Schläppy, Marie-Lise; Guerin, Andrew J

    2017-05-01

    Wave energy devices are novel structures in the marine environment and, as such, provide a unique habitat for biofouling organisms. In this study, destructive scrape samples and photoquadrats were used to characterise the temperate epibenthic community present on prototypes of the Pelamis wave energy converter. The biofouling observed was extensive and diverse with 115 taxa recorded including four non-native species. Vertical zonation was identified on the sides of the device, with an algae-dominated shallow subtidal area and a deeper area characterised by a high proportion of suspension-feeding invertebrates. Differences in species composition and biomass were also observed between devices, along the length of the device and between sampling dates. This research provides an insight into the variation of biofouling assemblages on a wave energy device as well as the potential technical and ecological implications associated with biofouling on marine renewable energy structures.

  5. Coating of reverse osmosis membranes with amphiphilic copolymers for biofouling control

    KAUST Repository

    Bucs, Szilard

    2017-05-30

    Surface coating of membranes may be a promising option to control biofilm development and biofouling impact on membrane performance of spiral-wound reverse osmosis (RO) systems. The objective of this study was to investigate the impact of an amphiphilic copolymer coating on biofilm formation and biofouling control. The coating was composed of both hydrophilic and hydrophobic monomers hydroxyethyl methacrylate (HEMA) and perfluorodecyl acrylate (PFA), respectively. Commercial RO membranes were coated with HEMA-PFA copolymer film. Long and short term biofouling studies with coated and uncoated membranes and feed spacer were performed using membrane fouling simulators (MFSs) operated in parallel, fed with water containing nutrients. For the long-term studies pressure drop development in time was monitored and after eight days the MFSs were opened and the accumulated biofilm on the membrane and spacer sheets was quantified and characterized. The presence of the membrane coating was determined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Results showed that the amphiphilic coating (i) delayed biofouling (a lower pressure drop increase by a factor of 3 and a lower accumulated active biomass amount by a factor of 6), (ii) influenced the biofilm composition (23% lower polysaccharides and 132% higher protein content) and (iii) was still completely present on the membrane at the end of the biofouling study, showing that the coating was strongly attached to the membrane surface. Using coated membranes and feed spacers in combination with advanced cleaning strategies may be a suitable way to control biofouling.

  6. Coating of reverse osmosis membranes with amphiphilic copolymers for biofouling control

    KAUST Repository

    Bucs, Szilard; Valladares Linares, Rodrigo; Siddiqui, Amber; Matin, Asif; Khan, Zafarullah; van Loosdrecht, Mark C.M.; Yang, Rong; Wang, Minghui; Gleason, Karen K.; Kruithof, Joop C.; Vrouwenvelder, Johannes S.

    2017-01-01

    Surface coating of membranes may be a promising option to control biofilm development and biofouling impact on membrane performance of spiral-wound reverse osmosis (RO) systems. The objective of this study was to investigate the impact of an amphiphilic copolymer coating on biofilm formation and biofouling control. The coating was composed of both hydrophilic and hydrophobic monomers hydroxyethyl methacrylate (HEMA) and perfluorodecyl acrylate (PFA), respectively. Commercial RO membranes were coated with HEMA-PFA copolymer film. Long and short term biofouling studies with coated and uncoated membranes and feed spacer were performed using membrane fouling simulators (MFSs) operated in parallel, fed with water containing nutrients. For the long-term studies pressure drop development in time was monitored and after eight days the MFSs were opened and the accumulated biofilm on the membrane and spacer sheets was quantified and characterized. The presence of the membrane coating was determined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Results showed that the amphiphilic coating (i) delayed biofouling (a lower pressure drop increase by a factor of 3 and a lower accumulated active biomass amount by a factor of 6), (ii) influenced the biofilm composition (23% lower polysaccharides and 132% higher protein content) and (iii) was still completely present on the membrane at the end of the biofouling study, showing that the coating was strongly attached to the membrane surface. Using coated membranes and feed spacers in combination with advanced cleaning strategies may be a suitable way to control biofouling.

  7. Evaluation of biofouling in stainless microfluidic channels for implantable multilayered dialysis device

    Science.gov (United States)

    Ota, Takashi; To, Naoya; Kanno, Yoshihiko; Miki, Norihisa

    2017-06-01

    An implantable artificial kidney can markedly improve the quality of life of renal disease patients. Our group has developed an implantable multilayered dialysis system consisting of microfluidic channels and dialysis membranes. Long-term evaluation is necessary for implant devices where biofouling is a critical factor, culminating in the deterioration of dialysis performance. Our previous work revealed that surface conditions, which depend on the manufacturing process, determine the amount of biofouling, and that electrolytic etching is the most suitable technique for forming a channel wall free of biofouling. In this study, we investigated the electrolytic etching conditions in detail. We conducted in vitro experiments for 7 d and evaluated the adhesion of biomaterials by scanning electron microscopy. The experiments revealed that a surface mirror-finished by electrolytic etching effectively prevents biofouling.

  8. Biofouling control of industrial seawater cooling towers

    KAUST Repository

    Albloushi, Mohammed

    2017-11-01

    The use of seawater in cooling towers for industrial applications has much merit in the Gulf Cooperation Council countries due to the scarcity and availability of fresh water. Seawater make-up in cooling towers is deemed the most feasible because of its unlimited supply in coastal areas. Such latent-heat removal with seawater in cooling towers is several folds more efficient than sensible heat extraction via heat exchangers. Operational challenges such as scaling, corrosion, and biofouling are a major challenge in conventional cooling towers, where the latter is also a major issue in seawater cooling towers. Biofouling can significantly hamper the efficiency of cooling towers. The most popular methods used in cooling treatment to control biofouling are disinfection by chlorination. However, the disadvantages of chlorination are formation of harmful disinfection byproducts in the presence of high organic loading and safety concerns in the storage of chlorine gas. In this study, the research focuses on biofouling control in seawater cooling towers by investigating two different approaches. The first strategy addresses the use of alternative oxidants (i.e. ozone micro-bubbles and chlorine dioxide) in treatment of cooling towers. The second strategy investigates removing nutrients in seawater using granular activated carbon filter column and ultrafiltration to prevent the growth of microorganisms. Laboratory bench-scale tests in terms of temperature, cycle of concentration, dosage, etc. indicated that, at lower oxidant dosages (total residual oxidant (TRO) equivalent = 0.1 mg/l Cl2), chlorine dioxide had a better disinfection effect than chlorine and ozone. The performance of oxidizing biocides at pilot scale, operating at assorted conditions, showed that for the disinfectants tested, ozone could remove 95 % bioactivity of total number of bacteria and algae followed by chlorine dioxide at 85%, while conventional chlorine dosing only gave 60% reduction in bioactivities

  9. Mini-review: Assessing the drivers of ship biofouling management--aligning industry and biosecurity goals.

    Science.gov (United States)

    Davidson, Ian; Scianni, Christopher; Hewitt, Chad; Everett, Richard; Holm, Eric; Tamburri, Mario; Ruiz, Gregory

    2016-01-01

    Biofouling exerts a frictional and cost penalty on ships and is a direct cause of invasion by marine species. These negative consequences provide a unifying purpose for the maritime industry and biosecurity managers to prevent biofouling accumulation and transfer, but important gaps exist between these sectors. This mini-review examines the approach to assessments of ship biofouling among sectors (industry, biosecurity and marine science) and the implications for existing and emerging management of biofouling. The primary distinctions between industry and biosecurity in assessment of vessels biofouling revolve around the resolution of biological information collected and the specific wetted surface areas of primary concern to each sector. The morphological characteristics of biofouling and their effects on propulsion dynamics are of primary concern to industry, with an almost exclusive focus on the vertical sides and flat bottom of hulls and an emphasis on antifouling and operational performance. In contrast, the identity, biogeography, and ecology of translocated organisms is of highest concern to invasion researchers and biosecurity managers and policymakers, especially as it relates to species with known histories of invasion elsewhere. Current management practices often provide adequate, although not complete, provision for hull surfaces, but niche areas are well known to enhance biosecurity risk. As regulations to prevent invasions emerge in this arena, there is a growing opportunity for industry, biosecurity and academic stakeholders to collaborate and harmonize efforts to assess and manage biofouling of ships that should lead to more comprehensive biofouling solutions that promote industry goals while reducing biosecurity risk and greenhouse gas emissions.

  10. Early non-destructive biofouling detection and spatial distribution: Application of oxygen sensing optodes

    KAUST Repository

    Farhat, Nadia; Staal, Marc; Siddiqui, Amber; Borisov, S.M.; Bucs, Szilard; Vrouwenvelder, Johannes S.

    2015-01-01

    The spatial and quantitative information on biological activity will lead to better understanding of the biofouling processes, contributing to the development of more effective biofouling control strategies.

  11. Biofouling Control in Spiral-Wound Membrane Systems: Impact of Feed Spacer Modification and Biocides

    KAUST Repository

    Siddiqui, Amber

    2016-12-01

    High-quality drinking water can be produced with membrane-based filtration processes like reverse osmosis and nanofiltration. One of the major problems in these membrane systems is biofouling that reduces the membrane performance, increasing operational costs. Current biofouling control strategies such as pre-treatment, membrane modification, and chemical cleaning are not sufficient in all cases. Feed spacers are thin (0.8 mm), complex geometry meshes that separate membranes in a module. The main objective of this research was to evaluate whether feed spacer modification is a suitable strategy to control biofouling. Membrane fouling simulator studies with six feed spacers showed differences in biofouled spacer performance, concluding that (i) spacer geometry influences biofouling impact and (ii) biofouling studies are essential for evaluation of spacer biofouling impact. Computed tomography (CT) was found as a suitable technique to obtain three-dimensional (3D) measurements of spacers, enabling more representative mathematical modeling of hydraulic behavior of spacers in membrane systems. A strategy for developing, characterizing, and testing of spacers by numerical modeling, 3D printing of spacers and experimental membrane fouling simulator studies was developed. The combination of modeling and experimental testing of 3D printed spacers is a promising strategy to develop advanced spacers aiming to reduce the impact of biofilm formation on membrane performance and to improve the cleanability of spiral-wound membrane systems.

  12. Experimental studies on the effect of different metallic substrates on marine biofouling.

    Science.gov (United States)

    Vedaprakash, L; Dineshram, R; Ratnam, Krupa; Lakshmi, K; Jayaraj, K; Mahesh Babu, S; Venkatesan, R; Shanmugam, A

    2013-06-01

    In the wake of adoption of the resolution by the International Maritime Organization to control biofouling on vessels, which is recognized as a major vector for transfer of invasive species, this study attempts to create a baseline data on major hard-shelled biofouling organisms in the harbour waters. This study was primarily focused towards understanding the biofouling and corrosion pattern on various metals and their performance under immersed condition in a marine environment, at 0.3 and 3.0m depths. Furthermore, the study attempts to understand the surface dependent characteristics of barnacle base plate and its adhesion strength. Barnacle, mussels and oysters were the major fouling organisms accounting for 72.33% of the variation. Stainless steel and Titanium panels showed the highest average biofouling load of 176.36 and 168.35 g/300 cm(2), respectively. The variance in biofouling between metals and depths was highly significant at p<0.001 and p<0.01, respectively. Morphology of barnacle base plate interfacial surface varied between metals. Barnacles with 8-9 mm base diameter showed the maximum adhesion strength in shear of 6.86±0.95 kPa. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Air bubbles induce a critical continuous stress to prevent marine biofouling accumulation

    Science.gov (United States)

    Belden, Jesse; Menesses, Mark; Dickenson, Natasha; Bird, James

    2017-11-01

    Significant shear stresses are needed to remove established hard fouling organisms from a ship hull. Given that there is a link between the amount of time that fouling accumulates and the stress required to remove it, it is not surprising that more frequent grooming requires less shear stress. One approach to mitigate marine biofouling is to continuously introduce a curtain of air bubbles under a submerged surface; it is believed that this aeration exploits the small stresses induced by rising bubbles to continuously prevent accumulation. Although curtains of rising bubbles have successfully prevented biofouling accumulation, it is unclear if a single stream of bubbles could maintain a clean surface. In this talk, we show that single bubble stream aeration can prevent biofouling accumulation in regions for which the average wall stress exceeds approximately 0.01 Pa. This value is arrived at by comparing observations of biofouling growth and prevention from field studies with laboratory measurements that probe the associated flow fields. We also relate the spatial and temporal characteristics of the flow to the size and frequency of the rising bubbles, which informs the basic operating conditions required for aeration to continuously prevent biofouling accumulation.

  14. Effects of biofouling on the sinking behavior of microplastics

    Science.gov (United States)

    Kaiser, David; Kowalski, Nicole; Waniek, Joanna J.

    2017-12-01

    Although plastic is ubiquitous in marine systems, our current knowledge of transport mechanisms is limited. Much of the plastic entering the ocean sinks; this is intuitively obvious for polymers such as polystyrene (PS), which have a greater density than seawater, but lower density polymers like polyethylene (PE) also occur in sediments. Biofouling can cause large plastic objects to sink, but this phenomenon has not been described for microplastics microplastic particles in estuarine and coastal waters to determine how biofouling changes their sinking behavior. Sinking velocities of PS increased by 16% in estuarine water (salinity 9.8) and 81% in marine water (salinity 36) after 6 weeks of incubation. Thereafter sinking velocities decreased due to lower water temperatures and reduced light availability. Biofouling did not cause PE to sink during the 14 weeks of incubation in estuarine water, but PE started to sink after six weeks in coastal water when sufficiently colonized by blue mussels Mytilus edulis, and its velocity continued to increase until the end of the incubation period. Sinking velocities of these PE pellets were similar irrespective of salinity (10 vs. 36). Biofilm composition differed between estuarine and coastal stations, presumably accounting for differences in sinking behavior. We demonstrate that biofouling enhances microplastic deposition to marine sediments, and our findings should improve microplastic transport models.

  15. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-06-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  16. Impact of spacer thickness on biofouling in forward osmosis.

    Science.gov (United States)

    Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

    2014-06-15

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo; Bucs, Szilard; Li, Z.; AbuGhdeeb, M.; Amy, Gary L.; Vrouwenvelder, Johannes S.

    2014-01-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  18. Biofouling of Cr-Nickel Spray Coated Films on Steel Surfaces

    International Nuclear Information System (INIS)

    Yoshida, Kento; Kanematsu, Hideyuki; Kuroda, Daisuke; Ikigai, Hajime; Kogo, Takeshi; Yokoyama, Seiji

    2012-01-01

    Nowadays, corrosion of metals brings us serious economic loss and it often reaches several percentage of GNP. Particularly the marine corrosion was serious and the counter measure was very hard to be established, since the number of factors is huge and complicated. One of the complicated factors in marine corrosion is biofouling. Biofouling was classified into two main categories, microfouling and macrofouling. The former is composed of biofilm formation mainly. Marine bacteria are attached to material surfaces, seeking for nutrition in oligotrophic environment and they excrete polysaccharide to form biofilm on metal surfaces. Then larger living matters are attached on the biofilms to develop biofouling on metal surfaces, which often lead loss and failures of metals in marine environments. From the viewpoint of corrosion protection and maintenance of marine structures, biofouling should be mitigated as much as possible. In this study, we applied spray coating to steels and investigated if chromium-nickel spray coating could mitigate the biofouling, being compared with the conventional aluminium-zinc spray coating in marine environments. The specimens used for this investigation are aluminium, zinc, aluminium-zinc, stacked chromium/nickel and those films were formed on carbon steel (JIS SS400). And the pores formed by spray coating were sealed by a commercial reagent for some specimens. All of those specimens were immersed into sea water located at Marina Kawage (854-3, Chisato, Tsu, Mie Prefecture) in Ise Bay for two weeks. The depth of the specimen was two meter from sea water surface and the distance was always kept constant, since they were suspended from the floating pier. The temperature in sea water changed from 10 to 15 degrees Celsius during the immersion test. The biofouling behavior was investigated by low vacuum SEM (Hitachi Miniscope TM1000) and X-ray fluorescent analysis. When the spray coated specimens with and without sealing agents were compared

  19. Do biological-based strategies hold promise to biofouling control in MBRs?

    KAUST Repository

    Malaeb, Lilian

    2013-10-01

    Biofouling in membrane bioreactors (MBRs) remains a primary challenge for their wider application, despite the growing acceptance of MBRs worldwide. Research studies on membrane fouling are extensive in the literature, with more than 200 publications on MBR fouling in the last 3 years; yet, improvements in practice on biofouling control and management have been remarkably slow. Commonly applied cleaning methods are only partially effective and membrane replacement often becomes frequent. The reason for the slow advancement in successful control of biofouling is largely attributed to the complex interactions of involved biological compounds and the lack of representative-for-practice experimental approaches to evaluate potential effective control strategies. Biofouling is driven by microorganisms and their associated extra-cellular polymeric substances (EPS) and microbial products. Microorganisms and their products convene together to form matrices that are commonly treated as a black box in conventional control approaches. Biological-based antifouling strategies seem to be a promising constituent of an effective integrated control approach since they target the essence of biofouling problems. However, biological-based strategies are in their developmental phase and several questions should be addressed to set a roadmap for translating existing and new information into sustainable and effective control techniques. This paper investigates membrane biofouling in MBRs from the microbiological perspective to evaluate the potential of biological-based strategies in offering viable control alternatives. Limitations of available control methods highlight the importance of an integrated anti-fouling approach including biological strategies. Successful development of these strategies requires detailed characterization of microorganisms and EPS through the proper selection of analytical tools and assembly of results. Existing microbiological/EPS studies reveal a number of

  20. Biofouling investigation in membrane filtration systems using Optical Coherence Tomography (OCT)

    KAUST Repository

    Fortunato, Luca

    2017-10-01

    Biofouling represents the main problem in membrane filtration systems. Biofouling arises when the biomass growth negatively impacts the membrane performance parameters (i.e. flux decrease and feed channel pressure drop). Most of the available techniques for characterization of biofouling involve membrane autopsies, providing information ex-situ destructively at the end of the process. OCT, is non-invasive imaging technique, able to acquire scans in-situ and non-destructively. The objective of this study was to evaluate the suitability of OCT as in-situ and non-destructive tool to gain a better understanding of biofouling behavior in membrane filtration systems. The OCT was employed to study the fouling behavior in two different membrane configurations: (i) submerged flat sheet membrane and (ii) spacer filled channel. Through the on-line acquisition of OCT scans and the study of the biomass morphology, it was possible to relate the impact of the fouling on the membrane performance. The on-line monitoring of biofilm formation on a flat sheet membrane was conducted in a gravity-driven submerged membrane bioreactor (SMBR) for 43 d. Four different phases were observed linking the variations in permeate flux with changes in biofilm morphology. Furthermore, the biofilm morphology was used in computational fluid dynamics (CFD) simulation to better understand the role of biofilm structure on the filtration mechanisms. The time-resolved OCT analysis was employed to study the biofouling development at the early stage. Membrane coverage and average biofouling layer thickness were found to be linearly correlated with the permeate flux pattern. An integrated characterization methodology was employed to characterize the fouling on a flat sheet membrane, involving the use of OCT as first step followed by membrane autopsies, revealing the presence of a homogeneous layer on the surface. In a spacer filled channel a 3D OCT time series analysis of biomass development under

  1. Biofouling in forward osmosis systems: An experimental and numerical study.

    Science.gov (United States)

    Bucs, Szilárd S; Valladares Linares, Rodrigo; Vrouwenvelder, Johannes S; Picioreanu, Cristian

    2016-12-01

    This study evaluates with numerical simulations supported by experimental data the impact of biofouling on membrane performance in a cross-flow forward osmosis (FO) system. The two-dimensional numerical model couples liquid flow with solute transport in the FO feed and draw channels, in the FO membrane support layer and in the biofilm developed on one or both sides of the membrane. The developed model was tested against experimental measurements at various osmotic pressure differences and in batch operation without and with the presence of biofilm on the membrane active layer. Numerical studies explored the effect of biofilm properties (thickness, hydraulic permeability and porosity), biofilm membrane surface coverage, and biofilm location on salt external concentration polarization and on the permeation flux. The numerical simulations revealed that (i) when biofouling occurs, external concentration polarization became important, (ii) the biofilm hydraulic permeability and membrane surface coverage have the highest impact on water flux, and (iii) the biofilm formed in the draw channel impacts the process performance more than when formed in the feed channel. The proposed mathematical model helps to understand the impact of biofouling in FO membrane systems and to develop possible strategies to reduce and control biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Biofouling in forward osmosis systems: An experimental and numerical study

    KAUST Repository

    Bucs, Szilard

    2016-09-20

    This study evaluates with numerical simulations supported by experimental data the impact of biofouling on membrane performance in a cross-flow forward osmosis (FO) system. The two-dimensional numerical model couples liquid flow with solute transport in the FO feed and draw channels, in the FO membrane support layer and in the biofilm developed on one or both sides of the membrane. The developed model was tested against experimental measurements at various osmotic pressure differences and in batch operation without and with the presence of biofilm on the membrane active layer. Numerical studies explored the effect of biofilm properties (thickness, hydraulic permeability and porosity), biofilm membrane surface coverage, and biofilm location on salt external concentration polarization and on the permeation flux. The numerical simulations revealed that (i) when biofouling occurs, external concentration polarization became important, (ii) the biofilm hydraulic permeability and membrane surface coverage have the highest impact on water flux, and (iii) the biofilm formed in the draw channel impacts the process performance more than when formed in the feed channel. The proposed mathematical model helps to understand the impact of biofouling in FO membrane systems and to develop possible strategies to reduce and control biofouling. © 2016 Elsevier Ltd

  3. Biofouling of spiral wound membrane systems

    NARCIS (Netherlands)

    Vrouwenvelder, J.S.

    2009-01-01

    Biofouling of spiral wound membrane systems High quality drinking water can be produced with membrane filtration processes like reverse osmosis (RO) and nanofiltration (NF). Because the global demand for fresh clean water is increasing, these membrane technologies will increase in importance in the

  4. The effect of vessel speed on the survivorship of biofouling organisms at different hull locations.

    Science.gov (United States)

    Coutts, Ashley D M; Piola, Richard F; Taylor, Michael D; Hewitt, Chad L; Gardner, Jonathan P A

    2010-07-01

    This study used a specially designed MAGPLATE system to quantify the en route survivorship and post-voyage recovery of biofouling assemblages subjected to short voyages (biofouling organisms amongst hull locations, biofouling cover and richness were markedly reduced on faster vessels relative to slower craft. Therefore, the potential inoculum size of non-indigenous marine species and richness is likely to be reduced for vessels that travel at faster speeds (> 14 knots), which is likely to also reduce the chances of successful introductions. Despite this, the magnitude of introductions from biofouling on fast vessels can be considered minor, especially for species richness where 90% of source-port species were recorded at destinations.

  5. The impact and control of biofouling in marine aquaculture: a review.

    Science.gov (United States)

    Fitridge, Isla; Dempster, Tim; Guenther, Jana; de Nys, Rocky

    2012-01-01

    Biofouling in marine aquaculture is a specific problem where both the target culture species and/or infrastructure are exposed to a diverse array of fouling organisms, with significant production impacts. In shellfish aquaculture the key impact is the direct fouling of stock causing physical damage, mechanical interference, biological competition and environmental modification, while infrastructure is also impacted. In contrast, the key impact in finfish aquaculture is the fouling of infrastructure which restricts water exchange, increases disease risk and causes deformation of cages and structures. Consequently, the economic costs associated with biofouling control are substantial. Conservative estimates are consistently between 5-10% of production costs (equivalent to US$ 1.5 to 3 billion yr(-1)), illustrating the need for effective mitigation methods and technologies. The control of biofouling in aquaculture is achieved through the avoidance of natural recruitment, physical removal and the use of antifoulants. However, the continued rise and expansion of the aquaculture industry and the increasingly stringent legislation for biocides in food production necessitates the development of innovative antifouling strategies. These must meet environmental, societal, and economic benchmarks while effectively preventing the settlement and growth of resilient multi-species consortia of biofouling organisms.

  6. Exploring the mechanisms of rising bubbles in marine biofouling prevention

    Science.gov (United States)

    Menesses, Mark; Belden, Jesse; Dickenson, Natasha; Bird, James

    2015-11-01

    Fluid motion, such as flow past a ship, is known to inhibit the growth of marine biofouling. Bubbles rising along a submerged structure also exhibit this behavior, which is typically attributed to buoyancy induced flow. However, the bubble interface may also have a direct influence on inhibiting growth that is independent of the surrounding flow. Here we aim to decouple these two mechanisms through a combination of field and laboratory experiments. In this study, a wall jet and a stream of bubbles are used to create two flows near a submerged solid surface where biofouling occurs. The flow structure characteristics were recorded using PIV. This experimental analysis allows for us to compare the efficacy of each flow relative to its flow parameters. Exploration of the mechanisms at play in the prevention of biofouling by use of rising bubbles provides a foundation to predict and optimize this antifouling technique under various conditions.

  7. The Effect of Hull Biofouling on Parameters Characterising Ship Propulsion System Efficiency

    Directory of Open Access Journals (Sweden)

    Tarełko Wiesła

    2015-01-01

    Full Text Available One of most important issues concerning technical objects is the increase of their operating performance. For a ship this performance mainly depends on the efficiency of its main pro-pulsion system and the resistance generated during its motion on water. The overall ship re-sistance, in turn, mainly depends on the hull friction resistance, closely related with the pres-ence of different types of roughness on the hull surface, including underwater part biofouling. The article analyses the effect of hull biofouling on selected parameters characterising the efficiency of the ship propulsion system with adjustable propeller. For this purpose a two-year research experiment was performed on a sailing vessel during its motor navigation phases. Based on the obtained results, three groups of characteristics were worked out for different combinations of engine rotational speed and adjustable propeller pitch settings. The obtained results have revealed that the phenomenon of underwater hull biofouling affects remarkably the parameters characterising propulsion system efficiency. In particular, the development of the biofouling layer leads to significant reduction of the speed of navigation.

  8. Biofouling in capillary and spiral wound membranes facilitated by marine algal bloom

    DEFF Research Database (Denmark)

    Villacorte, L.O.; Ekowati, Y.; Calix-Ponce, H.N.

    2017-01-01

    blooms. The tendency of AOM from bloom-forming marine algae to adhere to membranes and its ability to enhance biofilm growth were measured using atomic force microscopy, flow cytometry, liquid chromatography and accelerated membrane biofouling experiments. Adhesion force measurements indicate that AOM......Algal-derived organic matter (AOM), particularly transparent exopolymer particles, has been suspected to facilitate biofilm development in membrane systems (e.g., seawater reverse osmosis). This study demonstrates the possible role of AOM on biofouling in membrane systems affected by marine algal...... biodegradable nutrients. The abovementioned findings indicate that AOM facilitates the onset of membrane biofouling primarily as a conditioning platform and to some extent as a nutrient source for biofilm-forming bacteria....

  9. An Investigation of Low Biofouling Copper-charged Membranes

    Science.gov (United States)

    Asapu, Sunitha

    Water is essential for the survival of life on Earth, but pollutants in water can cause dangerous diseases and fatalities. The need for purified water has been increasing with increasing world population; however, natural sources of water such as rivers, lakes and streams, are progressively falling shorter and shorter of meeting water needs. The provision of clean, drinkable water to people is a key factor for the development of novel and alternative water purification technologies, such as membrane separations. Nanofiltration (NF) is a membrane separations technology that purifies water from lower quality sources, such as brackish water, seawater and wastewater. During the filtration of such sources, materials that are rejected by the membrane may accumulate on the surface of the membrane to foul it. Such materials include organic and inorganic matter, colloids, salts and microorganisms. The former four can often be controlled via pretreatment; however, the accumulation of microorganisms is more problematic to membranes. Biofouling is the accumulation and growth of microorganisms on the surface of membranes and on feed spacers. After attachment, microorganisms excrete extracellular polymeric substances (EPS), which form a matrix around the organism's outer surface as biofilm. These biofilms are detrimental and result in irreversible membrane fouling. Copper and silver ions inactivate the bacterial cells and prevent the DNA replication in microbial cells. Previous studies using copper-charged feed spacers have shown the ability of copper to control biofouling without a significant amount of copper leaching from copper-charged polypropylene (PP) feed spacers during crossflow filtration. Also, filtration using unmodified speed facers experienced almost 70% flux decline, while filtration using copper-charged feed spacers displayed only 25% flux decline. These intriguing results led to the hypothesis that the polymer chemistry could be extrapolated to produce membranes

  10. Biofouling in water systems--cases, causes and countermeasures.

    Science.gov (United States)

    Flemming, H-C

    2002-09-01

    Biofouling is referred to as the unwanted deposition and growth of biofilms. This phenomenon can occur in an extremely wide range of situations, from the colonisation of medical devices to the production of ultra-pure, drinking and process water and the fouling of ship hulls, pipelines and reservoirs. Although biofouling occurs in such different areas, it has a common cause, which is the biofilm. Biofilms are the most successful form of life on Earth and tolerate high amounts of biocides. For a sustainable anti-fouling strategy, an integrated approach is suggested which includes the analysis of the fouling situation, a selection of suitable components from the anti-fouling menu and an effective and representative monitoring of biofilm development.

  11. Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Stephen W.; James, Darryl L. (Texas Tech University, Lubbock, TX); Hibbs, Michael R.; Jones, Howland D. T.; Hart, William Eugene; Khalsa, Siri Sahib; Altman, Susan Jeanne; Clem, Paul Gilbert; Elimelech, Menachem (Yale University, New Haven, CT); Cornelius, Christopher James; Sanchez, Andres L. (LMATA Government Services LLC, Albuquerque, NM); Noek, Rachael M.; Ho, Clifford Kuofei; Kang, Seokatae (Yale University, New Haven, CT); Sun, Amy Cha-Tien; Adout, Atar (Yale University, New Haven, CT); McGrath, Lucas K. (LMATA Government Services LLC, Albuquerque, NM); Cappelle, Malynda A.; Cook, Adam W.

    2009-12-01

    Biofouling, the unwanted growth of biofilms on a surface, of water-treatment membranes negatively impacts in desalination and water treatment. With biofouling there is a decrease in permeate production, degradation of permeate water quality, and an increase in energy expenditure due to increased cross-flow pressure needed. To date, a universal successful and cost-effect method for controlling biofouling has not been implemented. The overall goal of the work described in this report was to use high-performance computing to direct polymer, material, and biological research to create the next generation of water-treatment membranes. Both physical (micromixers - UV-curable epoxy traces printed on the surface of a water-treatment membrane that promote chaotic mixing) and chemical (quaternary ammonium groups) modifications of the membranes for the purpose of increasing resistance to biofouling were evaluated. Creation of low-cost, efficient water-treatment membranes helps assure the availability of fresh water for human use, a growing need in both the U. S. and the world.

  12. Chlorination for biofouling control in power plant cooling water system - a review

    International Nuclear Information System (INIS)

    Satpathy, K.K.; Ruth Nithila, S.D.

    2008-01-01

    Fresh water is becoming a rare commodity day by day and thus power plant authorities are turning into sea to make use of the copious amount of seawater available at an economical rate for condenser cooling. Unfortunately, biofouling; the growth and colonization of marine organisms affect the smooth operation of power plant cooling water systems. This is more so, if the plant is located in tropical climate having clean environment, which enhances the variety and density of organisms. Thus, biofouling needs to be controlled for efficient operation of the power plant. Biocide used for biofouling control is decided based on three major criteria viz: it should be economically, operationally and environmentally acceptable to the power plant authorities. Chlorine among others stands out on the top and meets all the above requirements in spite of a few shortcomings. Therefore it is no wonder that still chlorine rules the roost and chlorination remains the most common method of biofouling control in power plant cooling water system all over the world. Although, it is easier said than done, a good amount of R and D work is essential before a precise chlorination regime is put into pragmatic use. This paper discusses in details the chemistry of chlorination such as chlorine demand, chlorine decay, break point chlorination, speciation of chlorine residual and role of temperature and ammonia on chlorination in biofouling control. Moreover, targeted and pulse chlorination are also discussed briefly. (author)

  13. Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators

    KAUST Repository

    Siddiqui, Amber; Lehmann, S.; Bucs, Szilard; Fresquet, M.; Fel, L.; Prest, E.I.E.C.; Ogier, J.; Schellenberg, C.; van Loosdrecht, M.C.M.; Kruithof, J.C.; Vrouwenvelder, Johannes S.

    2016-01-01

    Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems

  14. The role of "inert" surface chemistry in marine biofouling prevention.

    Science.gov (United States)

    Rosenhahn, Axel; Schilp, Sören; Kreuzer, Hans Jürgen; Grunze, Michael

    2010-05-07

    The settlement and colonization of marine organisms on submerged man-made surfaces is a major economic problem for many marine industries. The most apparent detrimental effects of biofouling are increased fuel consumption of ships, clogging of membranes and heat exchangers, disabled underwater sensors, and growth of biofoulers in aquaculture systems. The presently common-but environmentally very problematic-way to deal with marine biofouling is to incorporate biocides, which use biocidal products in the surface coatings to kill the colonizing organisms, into the surface coatings. Since the implementation of the International Maritime Organization Treaty on biocides in 2008, the use of tributyltin (TBT) is restricted and thus environmentally benign but effective surface coatings are required. In this short review, we summarize the different strategies which are pursued in academia and industry to better understand the mechanisms of biofouling and to develop strategies which can be used for industrial products. Our focus will be on chemically "inert" model surface coatings, in particular oligo- and poly(ethylene glycol) (OEG and PEG) functionalized surface films. The reasons for choosing this class of chemistry as an example are three-fold: Firstly, experiments on spore settlement on OEG and PEG coatings help to understand the mechanism of non-fouling of highly hydrated interfaces; secondly, these studies defy the common assumption that surface hydrophilicity-as measured by water contact angles-is an unambiguous and predictive tool to determine the fouling behavior on the surface; and thirdly, choosing this system is a good example for "interfacial systems chemistry": it connects the behavior of unicellular marine organisms with the antifouling properties of a hydrated surface coating with structural and electronic properties as derived from ab initio quantum mechanical calculations using the electronic wave functions of oxygen, hydrogen, and carbon. This short

  15. Acoustically excited encapsulated microbubbles and mitigation of biofouling

    KAUST Repository

    Qamar, Adnan; Fortunato, Luca; Leiknes, TorOve

    2017-01-01

    Provided herein is a universally applicable biofouling mitigation technology using acoustically excited encapsulated microbubbles that disrupt biofilm or biofilm formation. For example, a method of reducing biofilm formation or removing biofilm in a

  16. Automated Image Analysis of Offshore Infrastructure Marine Biofouling

    Directory of Open Access Journals (Sweden)

    Kate Gormley

    2018-01-01

    Full Text Available In the UK, some of the oldest oil and gas installations have been in the water for over 40 years and have considerable colonisation by marine organisms, which may lead to both industry challenges and/or potential biodiversity benefits (e.g., artificial reefs. The project objective was to test the use of an automated image analysis software (CoralNet on images of marine biofouling from offshore platforms on the UK continental shelf, with the aim of (i training the software to identify the main marine biofouling organisms on UK platforms; (ii testing the software performance on 3 platforms under 3 different analysis criteria (methods A–C; (iii calculating the percentage cover of marine biofouling organisms and (iv providing recommendations to industry. Following software training with 857 images, and testing of three platforms, results showed that diversity of the three platforms ranged from low (in the central North Sea to moderate (in the northern North Sea. The two central North Sea platforms were dominated by the plumose anemone Metridium dianthus; and the northern North Sea platform showed less obvious species domination. Three different analysis criteria were created, where the method of selection of points, number of points assessed and confidence level thresholds (CT varied: (method A random selection of 20 points with CT 80%, (method B stratified random of 50 points with CT of 90% and (method C a grid approach of 100 points with CT of 90%. Performed across the three platforms, the results showed that there were no significant differences across the majority of species and comparison pairs. No significant difference (across all species was noted between confirmed annotations methods (A, B and C. It was considered that the software performed well for the classification of the main fouling species in the North Sea. Overall, the study showed that the use of automated image analysis software may enable a more efficient and consistent

  17. Biofouling of inlet pipes affects water quality in running seawater aquaria and compromises sponge cell proliferation.

    Science.gov (United States)

    Alexander, Brittany E; Mueller, Benjamin; Vermeij, Mark J A; van der Geest, Harm H G; de Goeij, Jasper M

    2015-01-01

    Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed to equal in situ conditions, but may change due to the presence of biofouling organisms. Significantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium) were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and filter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the aquaria system, we investigated the influence of the presence and absence of the biofouling community on the functioning of the filter-feeding sponge Halisarca caerulea, by determining its choanocyte (filter cell) proliferation rates. We found a 34% increase in choanocyte proliferation rates following the replacement of the inlet pipe (i.e., removal of the biofouling community). This indicates that the physiological functioning of the sponge was compromised due to suboptimal food conditions within the aquarium resulting from the presence of the biofouling organisms in the inlet pipe. This study has implications for the husbandry and performance of experiments with marine organisms in running seawater aquaria systems. Inlet pipes should be checked regularly, and replaced if necessary, in order to avoid excessive biofouling and to approach in situ water quality.

  18. Quorum quenching bacteria can be used to inhibit the biofouling of reverse osmosis membranes.

    Science.gov (United States)

    Oh, Hyun-Suk; Tan, Chuan Hao; Low, Jiun Hui; Rzechowicz, Miles; Siddiqui, Muhammad Faisal; Winters, Harvey; Kjelleberg, Staffan; Fane, Anthony G; Rice, Scott A

    2017-04-01

    Over the last few decades, significant efforts have concentrated on mitigating biofouling in reverse osmosis (RO) systems, with a focus on non-toxic and sustainable strategies. Here, we explored the potential of applying quorum quenching (QQ) bacteria to control biofouling in a laboratory-scale RO system. For these experiments, Pantoea stewartii was used as a model biofilm forming organism because it was previously shown to be a relevant wastewater isolate that also forms biofilms in a quorum sensing (QS) dependent fashion. A recombinant Escherichia coli strain, which can produce a QQ enzyme, was first tested in batch biofilm assays and significantly reduced biofilm formation by P. stewartii. Subsequently, RO membranes were fouled with P. stewartii and the QQ bacterium was introduced into the RO system using two different strategies, direct injection and immobilization within a cartridge microfilter. When the QQ bacterial cells were directly injected into the system, N-acylhomoserine lactone signals were degraded, resulting in the reduction of biofouling. Similarly, the QQ bacteria controlled biofouling when immobilized within a microfilter placed downstream of the RO module to remove QS signals circulating in the system. These results demonstrate the proof-of-principle that QQ can be applied to control biofouling of RO membranes and may be applicable for use in full-scale plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Does Chlorination of Seawater Reverse Osmosis Membranes Control Biofouling?

    KAUST Repository

    Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

    2015-01-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full–scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  20. Does Chlorination of Seawater Reverse Osmosis Membranes Control Biofouling?

    KAUST Repository

    Khan, Muhammad Tariq

    2015-04-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full–scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  1. Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

    Science.gov (United States)

    Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-02-01

    There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Biofouling of Water Treatment Membranes: A Review of the Underlying Causes, Monitoring Techniques and Control Measures

    Directory of Open Access Journals (Sweden)

    Felicity A. Roddick

    2012-11-01

    Full Text Available Biofouling is a critical issue in membrane water and wastewater treatment as it greatly compromises the efficiency of the treatment processes. It is difficult to control, and significant economic resources have been dedicated to the development of effective biofouling monitoring and control strategies. This paper highlights the underlying causes of membrane biofouling and provides a review on recent developments of potential monitoring and control methods in water and wastewater treatment with the aim of identifying the remaining issues and challenges in this area.

  3. Selective suppression of in situ proliferation of scyphozoan polyps by biofouling

    International Nuclear Information System (INIS)

    Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

    2017-01-01

    An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7–8 months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. - Highlights: • Biofouling selectively controls in situ proliferation of scyphozoan polyps • The contribution

  4. Biofouling of inlet pipes affects water quality in running seawater aquaria and compromises sponge cell proliferation

    Directory of Open Access Journals (Sweden)

    Brittany E. Alexander

    2015-12-01

    Full Text Available Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed to equal in situ conditions, but may change due to the presence of biofouling organisms. Significantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and filter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the aquaria system, we investigated the influence of the presence and absence of the biofouling community on the functioning of the filter-feeding sponge Halisarca caerulea, by determining its choanocyte (filter cell proliferation rates. We found a 34% increase in choanocyte proliferation rates following the replacement of the inlet pipe (i.e., removal of the biofouling community. This indicates that the physiological functioning of the sponge was compromised due to suboptimal food conditions within the aquarium resulting from the presence of the biofouling organisms in the inlet pipe. This study has implications for the husbandry and performance of experiments with marine organisms in running seawater aquaria systems. Inlet pipes should be checked regularly, and replaced if necessary, in order to avoid excessive biofouling and to approach in situ water quality.

  5. Prospects and constraints in biofouling control at Madras Atomic Power Plant: a historical perspective

    International Nuclear Information System (INIS)

    Azariah, Jayapaul; Nair, K.V.K.

    1995-01-01

    The paper describes the various aspects of Madras Atomic Power Station -its prospects and constraints in biofouling control. It reviews the achievements in biofouling control. It also includes current studies on barnacles and mussels, suspended particulate matter as an antifoulant, flow conditions and larval settlement and biofilm and larval adhesion along with recommendations. (V.R.). 21 refs

  6. Novel Self-Cleaning Surfaces for Biofouling Prevention, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — One of the most problematic issues that facing efficient water reclamation processes for long duration space missions is biofilm growth and biofouling on RO membrane...

  7. Effect of ship hull form on the resistance penalty from biofouling.

    Science.gov (United States)

    Oliveira, Dinis; Larsson, Ann I; Granhag, Lena

    2018-03-01

    Hull biofouling is a well-known problem for the shipping industry, leading to increased resistance and fuel consumption. Considering that the effects of hull form on resistance are known to be higher for a less slender hull, it is hypothesised in this paper that the effect of biofouling roughness on resistance is also dependent on the hull form. To test this hypothesis, previously reported full-scale numerical results on a containership are re-analysed. Form effects on roughness penalties, corresponding to K ΔCT  = 0.058 ± 0.025, are observed at a low speed (19 knots, Re s  = 2.29 × 10 9 ), which are however cancelled out by traditionally neglected roughness effects on wave-making resistance at a higher speed (24 knots, Re s  = 2.89 × 10 9 ). It is concluded that hull form effects on biofouling penalties can be significant at low speeds, though not generalisable for higher speeds, namely when wave-making resistance corresponds to ≥ 29% of total resistance.

  8. Monitoring biofouling in the seawater tunnel of a coastal power station

    International Nuclear Information System (INIS)

    Sasikumar, N.

    1994-01-01

    Water level difference (head loss) between the seawater intake and the forebay was used to determine the biofouling growth in the cooling-water tunnel of Madras atomic power station, India. During 1986-87, due to biofouling growth in the tunnel, the head loss dropped beyond the permissible limits required for operation of the power plant. The head loss showed an improvement during 1988 and 1989, after exomotive chlorination was adopted instead of shock chlorination. Fouling biomass estimated from the head loss showed a heavy biomass build-up of 535.52 ± 102 tonnes in the tunnel during 1992. The head loss showed a seasonal pattern, very similar to the settlement pattern of foulants in the coastal waters, with maximum values during summer months. On the basis of head-loss data, a suitable chlorination practice has been recommended to the power station. The experience suggested that a continuous monitoring of head loss is a simple and reliable method of estimating and controlling biofouling in power-plant cooling-water tunnels. (author)

  9. Bivalve fouling of nuclear power plant service-water systems. Volume 2. Current status of biofouling surveillance and control techniques

    International Nuclear Information System (INIS)

    Daling, P.M.; Johnson, K.I.

    1985-03-01

    This report describes the current status of techniques for detection and control of cooling-water system fouling by bivalve mollusks at nuclear power plants. The effectiveness of these techniques is evaluated on the basis of information gathered from a literature review and in interviews with nuclear power plant personnel. Biofouling detection techniques examined in this report include regular maintenance, in-service inspection, and testing. Generally, these methods have been inadequate for detecting biofouling. Recommendations for improving biofouling detection capabilities are presented. Biofouling prevention (or control) methods that are examined in this report include intake screen systems, thermal treatment, preventive maintenance, chemical treatment alternatives, and antifoulant coatings. Recommendations for improving biofouling control methods at operating nuclear power plants are presented. Additional techniques that could be implemented at future power plants or that require further research are also described

  10. Biofouling and barnacle adhesion data for fouling-release coatings subjected to static immersion at seven marine sites

    Digital Repository Service at National Institute of Oceanography (India)

    Swain, G.; Anil, A.C.; Baier, R; Chia, F.-S.; Conte, E.; Cook, A.; Hadfield, M.; Haslbeck, E.; Holm, E.; Kavanagh, C.; Kohrs, D.; Kovach, B.; Lee, C.; Mazzella, L.; Meyer, A.E.; Qian, P.-Y.; Sawant, S.S.; Schultz, M.; Sigurdsson, J.; Smith, C.; Soo, L.; Terlizzi, A.; Wagh, A.; Zimmerman, R; Zupo, V.

    Little is known about the performance of fouling release coatings at different geographical locations. An investigation was designed to measure the differences in biofouling and biofouling adhesion strength on three known silicone formulations...

  11. Multivariate analysis of attachment of biofouling organisms in response to material surface characteristics.

    Science.gov (United States)

    Gatley-Montross, Caitlyn M; Finlay, John A; Aldred, Nick; Cassady, Harrison; Destino, Joel F; Orihuela, Beatriz; Hickner, Michael A; Clare, Anthony S; Rittschof, Daniel; Holm, Eric R; Detty, Michael R

    2017-12-29

    Multivariate analyses were used to investigate the influence of selected surface properties (Owens-Wendt surface energy and its dispersive and polar components, static water contact angle, conceptual sign of the surface charge, zeta potentials) on the attachment patterns of five biofouling organisms (Amphibalanus amphitrite, Amphibalanus improvisus, Bugula neritina, Ulva linza, and Navicula incerta) to better understand what surface properties drive attachment across multiple fouling organisms. A library of ten xerogel coatings and a glass standard provided a range of values for the selected surface properties to compare to biofouling attachment patterns. Results from the surface characterization and biological assays were analyzed separately and in combination using multivariate statistical methods. Principal coordinate analysis of the surface property characterization and the biological assays resulted in different groupings of the xerogel coatings. In particular, the biofouling organisms were able to distinguish four coatings that were not distinguishable by the surface properties of this study. The authors used canonical analysis of principal coordinates (CAP) to identify surface properties governing attachment across all five biofouling species. The CAP pointed to surface energy and surface charge as important drivers of patterns in biological attachment, but also suggested that differentiation of the surfaces was influenced to a comparable or greater extent by the dispersive component of surface energy.

  12. Plasma deposition of silver nanoparticles on ultrafiltration membranes: antibacterial and anti-biofouling properties.

    Science.gov (United States)

    Cruz, Mercedes Cecilia; Ruano, Gustavo; Wolf, Marcus; Hecker, Dominic; Vidaurre, Elza Castro; Schmittgens, Ralph; Rajal, Verónica Beatriz

    2015-02-01

    A novel and versatile plasma reactor was used to modify Polyethersulphone commercial membranes. The equipment was applied to: i) functionalize the membranes with low-temperature plasmas, ii) deposit a film of poly(methyl methacrylate) (PMMA) by Plasma Enhanced Chemical Vapor Deposition (PECVD) and, iii) deposit silver nanoparticles (SNP) by Gas Flow Sputtering. Each modification process was performed in the same reactor consecutively, without exposure of the membranes to atmospheric air. Scanning electron microscopy and transmission electron microscopy were used to characterize the particles and modified membranes. SNP are evenly distributed on the membrane surface. Particle fixation and transport inside membranes were assessed before- and after-washing assays by X-ray photoelectron spectroscopy depth profiling analysis. PMMA addition improved SNP fixation. Plasma-treated membranes showed higher hydrophilicity. Anti-biofouling activity was successfully achieved against Gram-positive ( Enterococcus faecalis ) and -negative ( Salmonella Typhimurium) bacteria. Therefore, disinfection by ultrafiltration showed substantial resistance to biofouling. The post-synthesis functionalization process developed provides a more efficient fabrication route for anti-biofouling and anti-bacterial membranes used in the water treatment field. To the best of our knowledge, this is the first report of a gas phase condensation process combined with a PECVD procedure in order to deposit SNP on commercial membranes to inhibit biofouling formation.

  13. Submarine Biofouling Control- Chlorination DATS Study at Pearl Harbor

    National Research Council Canada - National Science Library

    Wegand, John

    2001-01-01

    The intent of this document is to sumarize the chlorination studies performed at Naval Station, Pearl Harbor in support of biofouling control initiatives for the submarine community, as requested by NAVSEA 92T...

  14. Mitigation of membrane biofouling by d-amino acids: Effect of bacterial cell-wall property and d-amino acid type.

    Science.gov (United States)

    Wang, Si-Yu; Sun, Xue-Fei; Gao, Wen-Jing; Wang, Yi-Fu; Jiang, Bei-Bei; Afzal, Muhammad Zaheer; Song, Chao; Wang, Shu-Guang

    2018-04-01

    Development of novel approaches for biofouling mitigation is of crucial importance for membrane-based technologies. d-amino acids (d-AAs) have been proposed as a potential strategy to mitigate biofouling. However, the effect of bacterial cell-wall properties and d-AAs type on biofouling mitigation remains unclear. This study assesses the effect of d-AAs type on membrane biofouling control, towards Gram positive (G+) and Gram negative (G-) bacteria. Three kinds of d-AAs were found to inhibit both G+ and G- bacterial attachment in short-term attachment and dead-end filtration experiments. The existence of d-AAs reduces extracellular polysaccharides and proteins on the membrane, which may decrease membrane biofouling. Cross-flow filtration tests further indicated that d-AAs could effectively reduce membrane biofouling. The permeate flux recovery post chemical cleaning, improved for both P. aeruginosa and B. subtilis treated with d-AAs. The results obtained from this study enable better understanding of the role of d-AAs species on bacterial adhesion and biofilm formation. This may provide a new way to regulate biofilm formation by manipulating the species of d-AAs membrane systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Monitoring biofouling communities could reduce impacts to mussel aquaculture by allowing synchronisation of husbandry techniques with peaks in settlement.

    Science.gov (United States)

    Sievers, Michael; Dempster, Tim; Fitridge, Isla; Keough, Michael J

    2014-02-01

    Fouling organisms in bivalve aquaculture cause significant economic losses for the industry. Managing biofouling is typically reactive, and involves time- and labour-intensive removal techniques. Mussel spat settlement and biofouling were documented over 20 months at three mussel farms within Port Phillip Bay (PPB), Australia to determine if knowledge of settlement patterns could assist farmers in avoiding biofouling. Mussel spat settlement was largely confined to a 2-month period at one farm. Of the problematic foulers, Ectopleura crocea settlement varied in space and time at all three farms, whilst Ciona intestinalis and Pomatoceros taeniata were present predominantly at one farm and exhibited more distinct settlement periods. Within PPB, complete avoidance of biofouling is impossible. However, diligent monitoring may help farmers avoid peaks in detrimental biofouling species and allow them to implement removal strategies such as manual cleaning, and postpone grading and re-socking practices, until after these peaks.

  16. Early non-destructive biofouling detection in spiral wound RO Membranes using a mobile earth's field NMR

    KAUST Repository

    Fridjonsson, E.O.; Vogt, S.J.; Vrouwenvelder, Johannes S.; Johns, M.L.

    2015-01-01

    We demonstrate the use of Earth's field (EF) Nuclear Magnetic Resonance (NMR) to provide early non-destructive detection of active biofouling of a commercial spiral wound reverse osmosis (RO) membrane module. The RO membrane module was actively biofouled to different extents, by the addition of biodegradable nutrients to the feed stream, as revealed by a subtle feed-channel pressure drop increase. Easily accessible EF NMR parameters (signal relaxation parameters T1, T2 and the total NMR signal modified to be sensitive to stagnant fluid only) were measured and analysed in terms of their ability to detect the onset of biofouling. The EF NMR showed that fouling near the membrane module entrance significantly distorted the flow field through the whole membrane module. The total NMR signal is shown to be suitable for non-destructive early biofouling detection of spiral wound membrane modules, it was readily deployed at high (operational) flow rates, was particularly sensitive to flow field changes due to biofouling and could be deployed at any position along the membrane module axis. In addition to providing early fouling detection, the mobile EF NMR apparatus could also be used to (i) evaluate the production process of spiral wound membrane modules, and (ii) provide an in-situ determination of module cleaning process efficiency.

  17. Effect of different commercial feed spacers on biofouling of reverse osmosis membrane systems: A numerical study

    KAUST Repository

    Bucs, Szilard

    2014-06-01

    Feed spacers and hydrodynamics have been found relevant for the impact of biofouling on performance in reverse osmosis (RO) and nanofiltration (NF) membrane systems.The objectives of this study on biofouling development were to determine the impact of (i) linear flow velocity and bacterial cell load, (ii) biomass location and (iii) various feed spacer geometries as applied in practice as well as a modified geometry spacer.A three-dimensional mathematical model for biofouling of feed spacer channels including hydrodynamics, solute mass transport and biofilm formation was developed in COMSOL Multiphysics and MATLAB software.Results of this study indicate that the feed channel pressure drop increase caused by biofilm formation can be reduced by using thicker and/or modified feed spacer geometry and/or a lower flow rate in the feed channel. The increase of feed channel pressure drop by biomass accumulation is shown to be strongly influenced by the location of biomass. Results of numerical simulations are in satisfactory agreement with experimental data, indicating that this micro-scale mechanistic model is representative for practice. The developed model can help to understand better the biofouling process of spiral-wound RO and NF membrane systems and to develop strategies to reduce and control biofouling. © 2013 Elsevier B.V.

  18. Effect of different commercial feed spacers on biofouling of reverse osmosis membrane systems: A numerical study

    KAUST Repository

    Bucs, Szilard; Radu, Andrea I.; Lavric, Vasile; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

    2014-01-01

    Feed spacers and hydrodynamics have been found relevant for the impact of biofouling on performance in reverse osmosis (RO) and nanofiltration (NF) membrane systems.The objectives of this study on biofouling development were to determine the impact of (i) linear flow velocity and bacterial cell load, (ii) biomass location and (iii) various feed spacer geometries as applied in practice as well as a modified geometry spacer.A three-dimensional mathematical model for biofouling of feed spacer channels including hydrodynamics, solute mass transport and biofilm formation was developed in COMSOL Multiphysics and MATLAB software.Results of this study indicate that the feed channel pressure drop increase caused by biofilm formation can be reduced by using thicker and/or modified feed spacer geometry and/or a lower flow rate in the feed channel. The increase of feed channel pressure drop by biomass accumulation is shown to be strongly influenced by the location of biomass. Results of numerical simulations are in satisfactory agreement with experimental data, indicating that this micro-scale mechanistic model is representative for practice. The developed model can help to understand better the biofouling process of spiral-wound RO and NF membrane systems and to develop strategies to reduce and control biofouling. © 2013 Elsevier B.V.

  19. Early non-destructive biofouling detection in spiral wound RO Membranes using a mobile earth's field NMR

    KAUST Repository

    Fridjonsson, E.O.

    2015-04-20

    We demonstrate the use of Earth\\'s field (EF) Nuclear Magnetic Resonance (NMR) to provide early non-destructive detection of active biofouling of a commercial spiral wound reverse osmosis (RO) membrane module. The RO membrane module was actively biofouled to different extents, by the addition of biodegradable nutrients to the feed stream, as revealed by a subtle feed-channel pressure drop increase. Easily accessible EF NMR parameters (signal relaxation parameters T1, T2 and the total NMR signal modified to be sensitive to stagnant fluid only) were measured and analysed in terms of their ability to detect the onset of biofouling. The EF NMR showed that fouling near the membrane module entrance significantly distorted the flow field through the whole membrane module. The total NMR signal is shown to be suitable for non-destructive early biofouling detection of spiral wound membrane modules, it was readily deployed at high (operational) flow rates, was particularly sensitive to flow field changes due to biofouling and could be deployed at any position along the membrane module axis. In addition to providing early fouling detection, the mobile EF NMR apparatus could also be used to (i) evaluate the production process of spiral wound membrane modules, and (ii) provide an in-situ determination of module cleaning process efficiency.

  20. Gravity-driven membrane filtration as pretreatment for seawater reverse osmosis: linking biofouling layer morphology with flux stabilization.

    Science.gov (United States)

    Akhondi, Ebrahim; Wu, Bing; Sun, Shuyang; Marxer, Brigit; Lim, Weikang; Gu, Jun; Liu, Linbo; Burkhardt, Michael; McDougald, Diane; Pronk, Wouter; Fane, Anthony G

    2015-03-01

    In this study gravity-driven membrane (GDM) ultrafiltration is investigated for the pretreatment of seawater before reverse osmosis (RO). The impacts of temperature (21 ± 1 and 29 ± 1 °C) and hydrostatic pressure (40 and 100 mbar) on dynamic flux development and biofouling layer structure were studied. The data suggested pore constriction fouling was predominant at the early stage of filtration, during which the hydrostatic pressure and temperature had negligible effects on permeate flux. With extended filtration time, cake layer fouling played a major role, during which higher hydrostatic pressure and temperature improved permeate flux. The permeate flux stabilized in a range of 3.6 L/m(2) h (21 ± 1 °C, 40 mbar) to 7.3 L/m(2) h (29 ± 1 °C, 100 mbar) after slight fluctuations and remained constant for the duration of the experiments (almost 3 months). An increase in biofouling layer thickness and a variable biofouling layer structure were observed over time by optical coherence tomography and confocal laser scanning microscopy. The presence of eukaryotic organisms in the biofouling layer was observed by light microscopy and the microbial community structure of the biofouling layer was analyzed by sequences of 16S rRNA genes. The magnitude of permeate flux was associated with the combined effect of the biofouling layer thickness and structure. Changes in the biofouling layer structure were attributed to (1) the movement and predation behaviour of the eukaryotic organisms which increased the heterogeneous nature of the biofouling layer; (2) the bacterial debris generated by eukaryotic predation activity which reduced porosity; (3) significant shifts of the dominant bacterial species over time that may have influenced the biofouling layer structure. As expected, most of the particles and colloids in the feed seawater were removed by the GDM process, which led to a lower RO fouling potential. However, the dissolved organic carbon in the

  1. The biofilm ecology of microbial biofouling, biocide resistance and corrosion

    Energy Technology Data Exchange (ETDEWEB)

    White, D.C. [Univ. of Tennessee, Knoxville, TN (United States). Center for Environmental Biotechnology]|[Oak Ridge National Lab., TN (United States). Environmental Science Div.; Kirkegaard, R.D.; Palmer, R.J. Jr.; Flemming, C.A.; Chen, G.; Leung, K.T.; Phiefer, C.B. [Univ. of Tennessee, Knoxville, TN (United States). Center for Environmental Biotechnology; Arrage, A.A. [Univ. of Tennessee, Knoxville, TN (United States). Center for Environmental Biotechnology]|[Microbial Insights, Inc., Rockford, TN (United States)

    1997-06-01

    In biotechnological or bioremediation processes it is often the aim to promote biofilm formation, and maintain active, high density biomass. In other situations, biofouling can seriously restrict effective heat transport, membrane processes, and potentate macrofouling with loss of transportation efficiency. In biotechnological or bioremediation processes it is often the aim to promote biofilm formation, and maintain active, high density biomass. In other situations, biofouling can seriously restrict effective heat transport, membrane processes, and potentate macrofouling with loss of transportation efficiency. Heterogeneous distribution of microbes and/or their metabolic activity can promote microbially influenced corrosion (MIC) which is a multibillion dollar problem. Consequently, it is important that biofilm microbial ecology be understood so it can be manipulated rationally. It is usually simple to select organisms that form biofilms by flowing a considerably dilute media over a substratum, and propagating the organisms that attach. To examine the biofilm most expeditiously, the biomass accumulation, desquamation, and metabolic activities need to be monitored on-line and non-destructively. This on-line monitoring becomes even more valuable if the activities can be locally mapped in time and space within the biofilm. Herein the authors describe quantitative measures of microbial biofouling, the ecology of pathogens in drinking water distributions systems, and localization of microbial biofilms and activities with localized MIC.

  2. Measuring a critical stress for continuous prevention of marine biofouling accumulation with aeration.

    Science.gov (United States)

    Menesses, Mark; Belden, Jesse; Dickenson, Natasha; Bird, James

    2017-10-01

    When cleaning the hull of a ship, significant shear stresses are needed to remove established biofouling organisms. Given that there exists a link between the amount of time that fouling accumulates and the stress required to remove it, it is not surprising that more frequent grooming requires less shear stress. Yet, it is unclear if there is a minimum stress needed to prevent the growth of macrofouling in the limit of continuous grooming. This manuscript shows that single bubble stream aeration provides continuous grooming and prevents biofouling accumulation in regions where the average wall stress exceeds ~0.01 Pa. This value was found by comparing observations of biofouling growth from field studies with complementary laboratory measurements that probe the associated flow fields. These results suggest that aeration and other continuous grooming systems must exceed a wall stress of 0.01 Pa to prevent macrofouling accumulation.

  3. Nitric oxide treatment for the control of reverse osmosis membrane biofouling.

    Science.gov (United States)

    Barnes, Robert J; Low, Jiun Hui; Bandi, Ratnaharika R; Tay, Martin; Chua, Felicia; Aung, Theingi; Fane, Anthony G; Kjelleberg, Staffan; Rice, Scott A

    2015-04-01

    Biofouling remains a key challenge for membrane-based water treatment systems. This study investigated the dispersal potential of the nitric oxide (NO) donor compound, PROLI NONOate, on single- and mixed-species biofilms formed by bacteria isolated from industrial membrane bioreactor and reverse osmosis (RO) membranes. The potential of PROLI NONOate to control RO membrane biofouling was also examined. Confocal microscopy revealed that PROLI NONOate exposure induced biofilm dispersal in all but two of the bacteria tested and successfully dispersed mixed-species biofilms. The addition of 40 μM PROLI NONOate at 24-h intervals to a laboratory-scale RO system led to a 92% reduction in the rate of biofouling (pressure rise over a given period) by a bacterial community cultured from an industrial RO membrane. Confocal microscopy and extracellular polymeric substances (EPS) extraction revealed that PROLI NONOate treatment led to a 48% reduction in polysaccharides, a 66% reduction in proteins, and a 29% reduction in microbial cells compared to the untreated control. A reduction in biofilm surface coverage (59% compared to 98%, treated compared to control) and average thickness (20 μm compared to 26 μm, treated compared to control) was also observed. The addition of PROLI NONOate led to a 22% increase in the time required for the RO module to reach its maximum transmembrane pressure (TMP), further indicating that NO treatment delayed fouling. Pyrosequencing analysis revealed that the NO treatment did not significantly alter the microbial community composition of the membrane biofilm. These results present strong evidence for the application of PROLI NONOate for prevention of RO biofouling. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. Remediating biofouling of reverse osmosis membranes

    International Nuclear Information System (INIS)

    Siler, J.L.

    1991-01-01

    Several potential additives and the use of influent pH adjustment were examined to remediated the biofouling problem of the ETF reverse osmosis (RO) system. Tests were conducted with simulated RO feed containing salt, metal hydroxides and bacteria. The addition of sodium hexametaphosphate (SHMP), sodium bisulfite, and adjusting the influent pH to 3 were each successful in reducing the RO biofouling. Little or no benefit was found from the use of a biofilm remover (Filmtec Alkaline Cleaner) or the use of surfactants (Surfynol or sodium lauryl sulfate). In addition, Surfynol use resulted in irreversible fouling and necessitated membrane replacement. At the water recoveries used in the ETF (>90%), sodium bisulfite addition resulted in the recovery of 70--90% of the flux and almost complete restoration of the DF to prefouled conditions. Based on the bench-scale tests completed, IWT would recommend that sodium bisulfite addition be tested at the ETF. This testing would involve optimizing the amount of bisulfite required. In addition, it is recommended that the addition of SHMP or influent pH adjustment be evaluated since the relative differences in labscale tests were small and scale-up effects could be present. The ETF operating permit allows each to be added

  5. Variation in biofouling on different species of Indian timbers

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Wagh, A.B.

    Biofouling on twenty species of wood exposed in waters of Mormugao Harbour, Goa, India have been presented. Macrofouling biomass varied from species to species. Maximum biomass was recorded on Artocarpus chaplasha (4 kg/m2) and minimum on Hopea...

  6. Biofouling Organisms in the Field and for the Classroom.

    Science.gov (United States)

    Stout, Prentice K.

    1983-01-01

    Biofouling organisms are marine organisms that affix themselves to navigational buoys, floating docks, and pilings. Techniques for collecting these organisms for classroom use are described. General background information on the organisms and a list of common species are included. (JN)

  7. Biofouling and corrosion studies. Final report, Part I, May 1, 1976-December 1977

    Energy Technology Data Exchange (ETDEWEB)

    Mahalingam, L. M.

    1978-01-01

    Three sets of biofouling experiments were conducted. Two of these sets were done in the Pacific Ocean at Keahole Point, Hawaii, and one was in the Caribbean at St. Croix, Virgin Islands. Data and results from these experiments are presented and discussed. Heat transfer, biological, and metallurgical measurements are presented. A brief account of the data analysis procedures, and an assessment of the hardware performance are given. Recommendations are made to improve the quality of the current efforts in the OTEC Biofouling, Corrosion and Materials program.

  8. Impact of feed spacer and membrane modification by hydrophilic, bactericidal and biocidal coating on biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The influence of polydopamine- and polydopamine-. graft-poly(ethylene glycol)-coated feed spacers and membranes, copper-coated feed spacers, and commercially-available biostatic feed spacers on biofouling has been studied in membrane fouling simulators. Feed spacers and membranes applied in practical membrane filtration systems were used; biofouling development was monitored by feed channel pressure drop increase and biomass accumulation. Polydopamine and polydopamine-. g-PEG are hydrophilic surface modification agents expected to resist protein and bacterial adhesion, while copper feed spacer coatings and biocides infused in feed spacers are expected to restrict biological growth. Our studies showed that polydopamine and polydopamine-. g-PEG coatings on feed spacers and membranes, copper coatings on feed spacers, and a commercial biostatic feed spacer did not have a significant impact on feed channel pressure drop increase and biofilm accumulation as measured by ATP and TOC content. The studied spacer and membrane modifications were not effective for biofouling control; it is doubtful that feed spacer and membrane modification, in general, may be effective for biofouling control regardless of the type of applied coating. © 2012 Elsevier B.V.

  9. Amplified recruitment pressure of biofouling organisms in commercial salmon farms: potential causes and implications for farm management.

    Science.gov (United States)

    Bloecher, Nina; Floerl, Oliver; Sunde, Leif Magne

    2015-01-01

    The development of biofouling on finfish aquaculture farms presents challenges for the industry, but the factors underlying nuisance growths are still not well understood. Artificial settlement surfaces were used to examine two possible explanations for high rates of biofouling in Norwegian salmon farms: (1) increased propagule release during net cleaning operations, resulting in elevated recruitment rates; and (2) potential reservoir effects of farm surfaces. The presence of salmon farms was associated with consistently and substantially (up to 49-fold) elevated recruitment rates. Temporal patterns of recruitment were not driven by net cleaning. Resident populations of biofouling organisms were encountered on all submerged farm surfaces. Calculations indicate that a resident population of the hydroid Ectopleura larynx, a major biofouling species, could release between 0.3 × 10(9) and 4.7 × 10(9) larvae per farm annually. Such resident populations could form propagule reservoirs and be one explanation for the elevated recruitment pressure at salmon farms.

  10. Selective suppression of in situ proliferation of scyphozoan polyps by biofouling.

    Science.gov (United States)

    Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

    2017-01-30

    An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Biofouling evaluation in the seawater cooling circuit of an operating coastal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, P.S.; Veeramani, P.; Ershath, M.I.M.; Venugopalan, V.P. [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamil Nadu (India)

    2010-07-01

    Chlorination is the most commonly used method of biofouling control in cooling water systems of coastal power stations. In the present study, we report results of extensive sampling in different sections of the cooling water system of an operating power station undertaken during three consecutive maintenance shutdowns. The power plant employed continuous low level chlorination (0.2 ± 0.1 mg L{sup -1} TRO) with twice-a-week booster dosing (0.4 ± 0.1 mg L-1 TRO for 8 hours). In addition, the process seawater heat exchangers received supplementary dosing of bromide treatment (0.2 ± 0.1 mg L{sup -1} TRO for 1 hour in every 8 h shift). Biofouling samples were collected from the cooling water conduits, heat exchanger water boxes, pipelines, heated discharge conduits and outfall section during the annual maintenance shutdown of the plant in the years 2007, 2008 and 2009. Simultaneous monitoring of biofouling on test coupons in coastal waters enabled direct comparison of fouling situation on test panels and that in the cooling system. The data showed significant reduction in biofouling inside the cooling circuit as compared to the coastal waters. However, significant amount of fouling was still evident at several places, indicating inadequacy of the biocide treatment regime. The maximum load of 31.3 kg m{sup 2} y{sup -1} was observed in the conduits leading to the process seawater heat exchangers (PSW-HX) and the minimum of 1.3 kg m{sup 2} y{sup -1} was observed in the outfall section. Fouling loads of 12.2 - 14.7 kg m{sup 2} y{sup -1} were observed in the concrete conduits feeding the main condensers. Bromide treatment ahead of the PSW-HX could marginally reduce the fouling load in the downstream section of the dosing point; the HX inlets still showed good biofouling. Species diversity across the cooling water system showed the pre-condenser section to be dominated by green mussels (Perna viridis), pearl oysters (Pinctada sp.) and edible oysters (Crassostrea sp

  12. Biofouling evaluation in the seawater cooling circuit of an operating coastal power plant

    International Nuclear Information System (INIS)

    Murthy, P.S.; Veeramani, P.; Ershath, M.I.M.; Venugopalan, V.P.

    2010-01-01

    Chlorination is the most commonly used method of biofouling control in cooling water systems of coastal power stations. In the present study, we report results of extensive sampling in different sections of the cooling water system of an operating power station undertaken during three consecutive maintenance shutdowns. The power plant employed continuous low level chlorination (0.2 ± 0.1 mg L -1 TRO) with twice-a-week booster dosing (0.4 ± 0.1 mg L-1 TRO for 8 hours). In addition, the process seawater heat exchangers received supplementary dosing of bromide treatment (0.2 ± 0.1 mg L -1 TRO for 1 hour in every 8 h shift). Biofouling samples were collected from the cooling water conduits, heat exchanger water boxes, pipelines, heated discharge conduits and outfall section during the annual maintenance shutdown of the plant in the years 2007, 2008 and 2009. Simultaneous monitoring of biofouling on test coupons in coastal waters enabled direct comparison of fouling situation on test panels and that in the cooling system. The data showed significant reduction in biofouling inside the cooling circuit as compared to the coastal waters. However, significant amount of fouling was still evident at several places, indicating inadequacy of the biocide treatment regime. The maximum load of 31.3 kg m 2 y -1 was observed in the conduits leading to the process seawater heat exchangers (PSW-HX) and the minimum of 1.3 kg m 2 y -1 was observed in the outfall section. Fouling loads of 12.2 - 14.7 kg m 2 y -1 were observed in the concrete conduits feeding the main condensers. Bromide treatment ahead of the PSW-HX could marginally reduce the fouling load in the downstream section of the dosing point; the HX inlets still showed good biofouling. Species diversity across the cooling water system showed the pre-condenser section to be dominated by green mussels (Perna viridis), pearl oysters (Pinctada sp.) and edible oysters (Crassostrea sp.), whereas the post-condenser section and heat

  13. Bioinspired nanocoatings for biofouling prevention by photocatalytic redox reactions.

    Science.gov (United States)

    Sathe, Priyanka; Laxman, Karthik; Myint, Myo Tay Zar; Dobretsov, Sergey; Richter, Jutta; Dutta, Joydeep

    2017-06-15

    Aquaculture is a billion dollar industry and biofouling of aquaculture installations has heavy economic penalties. The natural antifouling (AF) defence mechanism of some seaweed that inhibits biofouling by production of reactive oxygen species (ROS) inspired us to mimic this process by fabricating ZnO photocatalytic nanocoating. AF activity of fishing nets modified with ZnO nanocoating was compared with uncoated nets (control) and nets painted with copper-based AF paint. One month experiment in tropical waters showed that nanocoatings reduce abundances of microfouling organisms by 3-fold compared to the control and had higher antifouling performance over AF paint. Metagenomic analysis of prokaryotic and eukaryotic fouling organisms using next generation sequencing platform proved that nanocoatings compared to AF paint were not selectively enriching communities with the resistant and pathogenic species. The proposed bio-inspired nanocoating is an important contribution towards environmentally friendly AF technologies for aquaculture.

  14. Green Materials Science and Engineering Reduces Biofouling: Approaches for Medical and Membrane-based Technologies

    Directory of Open Access Journals (Sweden)

    Kerianne M Dobosz

    2015-03-01

    Full Text Available Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety.

  15. Biofouling in forward osmosis systems: An experimental and numerical study

    KAUST Repository

    Bucs, Szilard; Valladares Linares, Rodrigo; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

    2016-01-01

    This study evaluates with numerical simulations supported by experimental data the impact of biofouling on membrane performance in a cross-flow forward osmosis (FO) system. The two-dimensional numerical model couples liquid flow with solute

  16. Pectinatella magnifica (Leidy, 1851) (Bryozoa, Phylactolaemata), a biofouling bryozoan recently introduced to China

    Science.gov (United States)

    Wang, Baoqiang; Wang, Hongzhu; Cui, Yongde

    2017-07-01

    Freshwater biofouling threatens a variety of human activities, from the supply of water and energy to recreation. Several species of freshwater bryozoans are notorious for clogging pipes and filters but have been relatively poorly studied to date. We report, for the first time, a biofouling species of freshwater bryozoan, Pectinatella magnifica (Leidy, 1851), from several freshwater rivers, lakes and ponds in China. A complete description, national distribution and the fouling problems are provided. Exactly how Pectinatella magnifica arrived in China remains unclear, but anthropochory and zoochory are considered to be important dispersal pathways.

  17. Role of Diatoms in marine biofouling

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A; Patil, J.S..; Mitbavkar, S.; DeCosta, P.M.; DeSilva, S.; Hegde, S.; Naik, R.

    . Ltd., New Delhi, pp. 293-6. de Nys, R., Leya, T., Maximilien, R., Afsar, A., Nair, P. S. R. & Steinberg, P. D. 1996. The need for standardized broad scale bioassay testing: a case study using the red alga Laurencia rigida. Biofouling 10:213-24. de...-1 Content-Type text/plain; charset=ISO-8859-1 Recent Advances on Applied Aspects of Indian Marine Algae with Reference to Global Scenario, Volume 1, A. Tewari (Ed.), 2006 Central Salt & Marine Chemicals Research Institute Role of Diatoms...

  18. Assessment of the anti-biofouling potentials of a copper iodide-doped nylon mesh.

    Science.gov (United States)

    Sato, Tetsuya; Fujimori, Yoshie; Nakayama, Tsuruo; Gotoh, Yasuo; Sunaga, Yoshihiko; Nemoto, Michiko; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2012-08-01

    We propose a copper iodide (CuI)-doped nylon mesh prepared using polyiodide ions as a precursor toward anti-biofouling polymer textile. The CuI-doped nylon mesh was subjected to the prevention of biofouling in marine environments. The attachment of the marine organisms was markedly inhibited on the CuI-doped nylon mesh surface until 249 days. Scanning electron microscopy-energy dispersive X-ray analysis indicated that copper compounds were maintained in the nylon mesh after the field experiment, although copper content in the nylon mesh was reduced. Therefore, the copper ions slowly dissolved from nylon mesh will contribute to the long-term prevention of biofouling. Furthermore, electron spin resonance analysis revealed the generation of reactive oxygen species (ROS) from CuI-doped nylon mesh after the field experiment. One of the possibilities for toxic action of copper ions will be the direct effect of Cu+ -induced ROS on biofilm forming on nylon mesh surface. The proposed polymer textile can be applied to fishing and aquafarming nets, mooring rope for ship, or silt fence to restrict polluted water in marine environments.

  19. Removing vessels from the water for biofouling treatment has the potential to introduce mobile non-indigenous marine species.

    Science.gov (United States)

    Coutts, Ashley D M; Valentine, Joseph P; Edgar, Graham J; Davey, Adam; Burgess-Wilson, Bella

    2010-09-01

    Vessels found contaminated with biofouling non-indigenous marine species are predominantly removed from the water and treated in vessel maintenance facilities (i.e., slipways, travel lifts and dry-docks). Using pre-fouled settlement plates to simulate a vessel's removal from the water for treatment, we demonstrate that a range of mobile organisms (including non-indigenous marine species) may be lost to the marine environment as a consequence of this process. We also determined that different levels of biofouling (primary, secondary and tertiary) and emersion durations (0.5, 5 and 15 min) affected the abundance and composition of mobile taxa lost to the marine environment. Primary biofouling plates lost 3.2% of total animals, secondary plates lost 19.8% and tertiary plates lost 8.2%, while hanging duration had only minor effects. The results suggest that removing vessels contaminated with biofouling non-indigenous marine species from the water for treatment may not be as biosecure as is currently recognised. Copyright 2010 Elsevier Ltd. All rights reserved.

  20. Biofouling control of industrial seawater cooling towers

    KAUST Repository

    Al-Bloushi, Mohammed

    2017-01-01

    In this study, the research focuses on biofouling control in seawater cooling towers by investigating two different approaches. The first strategy addresses the use of alternative oxidants (i.e. ozone micro-bubbles and chlorine dioxide) in treatment of cooling towers. The second strategy investigates removing nutrients in seawater using granular activated carbon filter column and ultrafiltration to prevent the growth of microorganisms. Laboratory bench-scale tests in terms of temperature, cycle of concentration, dosage, etc. indicated that, at lower oxidant dosages (total residual oxidant (TRO) equivalent = 0.1 mg/l Cl2), chlorine dioxide had a better disinfection effect than chlorine and ozone. The performance of oxidizing biocides at pilot scale, operating at assorted conditions, showed that for the disinfectants tested, ozone could remove 95 % bioactivity of total number of bacteria and algae followed by chlorine dioxide at 85%, while conventional chlorine dosing only gave 60% reduction in bioactivities. Test results of GAC bio-filter showed that around 70 % removal of total organic carbon in the seawater feed was achieved and was effective in keeping the microbial growth to a minimum. The measured results from this study enable designers of seawater cooling towers to manage the biofouling problems when such cooling towers are extrapolated to a pilot scale.

  1. Epibiotic pressure contributes to biofouling invader success.

    Science.gov (United States)

    Leonard, Kaeden; Hewitt, Chad L; Campbell, Marnie L; Primo, Carmen; Miller, Steven D

    2017-07-12

    Reduced competition is a frequent explanation for the success of many introduced species. In benthic marine biofouling communities, space limitation leads to high rates of overgrowth competition. Some species can utilise other living organisms as substrate (epibiosis), proffering a competitive advantage for the epibiont. Additionally, some species can prevent or reduce epibiotic settlement on their surfaces and avoid being basibionts. To test whether epibiotic pressure differs between native and introduced species, we undertook ex situ experiments comparing bryozoan larval settlement to determine if introduced species demonstrate a greater propensity to settle as epibionts, and a reduced propensity to be basibionts, than native species. Here we report that introduced species opportunistically settle on any space (bare, native, or introduced), whereas native species exhibit a strong tendency to settle on and near other natives, but avoid settling on or near introduced basibionts. In addition, larvae of native species experience greater larval wastage (mortality) than introduced species, both in the presence and absence of living substrates. Introduced species' ability to settle on natives as epibionts, and in turn avoid epibiosis as basibionts, combined with significantly enhanced native larval wastage, provides a comprehensive suite of competitive advantages contributing to the invasion success of these biofouling species.

  2. Biofouling on artificial substrata in Muscat waters

    Directory of Open Access Journals (Sweden)

    Sergey Dobretsov

    2015-01-01

    Full Text Available Macro-fouling communities developed on acrylic, aluminum, wood and fiberglass panels were investigated after 4 months exposure in Marina Bandar al Rawdah and Marina Shangri La. Wet weight of biofouling was about 2-fold higher in Marina Bandar Rawdah and different communities were formed on the front and back sides of the panels. Differences between communities on different materials were less pronounced. In the second study, wet weight and community composition of macro-fouling communities on ceramic tiles at the depth of 1 m and 5 m in Marina Bandar al Rawdah were investigated. During 2008 – 2010, there were no differences between biomass of communities, while in 2011 biomass of macro-fouling was higher on tiles at 5 m. In December 2008 the minimal weight (0 kg/m2 and in September 2011 the maximal weight (26.3 kg/m2 of macro-fouling communities were recorded. In total, 27 invertebrate fouling species were found, which mostly (33% belonged to phylum Ectoprocta. Three invasive bryozoan (Bugula neritina, Zoobotryon verticillatum and Schizoporella errata and one invasive tunicate (Ciona intestinalis species were observed. Overall, this study indicates high biofouling pressure in Muscat marinas and suggests necessity of future studies of fouling communities in Oman waters.

  3. ANTI-BIOFOULING BY DEGRADATION OF POLYMERS

    Institute of Scientific and Technical Information of China (English)

    Chun-feng Ma; Hong-jun Yang; Guang-zhao Zhang

    2012-01-01

    Copolymers of methyl methacrylate (MMA) and acrylate terminated poly(ethylene oxide-co-ethylene carbonate)(PEOC) macromonomer (PEOCA) were synthesized,and the degradation of the polymers was investigated by use of quartz crystal microbalance with dissipation (QCM-D).It is shown that the polymeric surface exhibits degradation in seawater depending on the content of the side chains.Field tests in seawater show that the surface constructed by the copolymer can effectively inhibit marine biofouling because it can be self-renewed due to degradation of the copolymer.

  4. Biofouling community composition across a range of environmental conditions and geographical locations suitable for floating marine renewable energy generation.

    Science.gov (United States)

    Macleod, Adrian K; Stanley, Michele S; Day, John G; Cook, Elizabeth J

    2016-01-01

    Knowledge of biofouling typical of marine structures is essential for engineers to define appropriate loading criteria in addition to informing other stakeholders about the ecological implications of creating novel artificial environments. There is a lack of information regarding biofouling community composition (including weight and density characteristics) on floating structures associated with future marine renewable energy generation technologies. A network of navigation buoys were identified across a range of geographical areas, environmental conditions (tidal flow speed, temperature and salinity), and deployment durations suitable for future developments. Despite the perceived importance of environmental and temporal factors, geographical location explained the greatest proportion of the observed variation in community composition, emphasising the importance of considering geography when assessing the impact of biofouling on device functioning and associated ecology. The principal taxa associated with variation in biofouling community composition were mussels (Mytilus edulis), which were also important when determining loading criteria.

  5. Development of a setup to enable stable and accurate flow conditions for membrane biofouling studies

    KAUST Repository

    Bucs, Szilard

    2015-07-10

    Systematic laboratory studies on membrane biofouling require experimental conditions that are well defined and representative for practice. Hydrodynamics and flow rate variations affect biofilm formation, morphology, and detachment and impacts on membrane performance parameters such as feed channel pressure drop. There is a suite of available monitors to study biofouling, but systems to operate monitors have not been well designed to achieve an accurate, constant water flow required for a reliable determination of biomass accumulation and feed channel pressure drop increase. Studies were done with membrane fouling simulators operated in parallel with manual and automated flow control, with and without dosage of a biodegradable substrate to the feedwater to enhance biofouling rate. High flow rate variations were observed for the manual water flow system (up to ≈9%) compared to the automatic flow control system (<1%). The flow rate variation in the manual system was strongly increased by biofilm accumulation, while the automatic system maintained an accurate and constant water flow in the monitor. The flow rate influences the biofilm accumulation and the impact of accumulated biofilm on membrane performance. The effect of the same amount of accumulated biomass on the pressure drop increase was related to the linear flow velocity. Stable and accurate feedwater flow rates are essential for biofouling studies in well-defined conditions in membrane systems. © 2015 Balaban Desalination Publications. All rights reserved.

  6. Use of rhamnolipid biosurfactant for membrane biofouling prevention and cleaning.

    Science.gov (United States)

    Kim, Lan Hee; Jung, Yongmoon; Kim, Sung-Jo; Kim, Chang-Min; Yu, Hye-Weon; Park, Hee-Deung; Kim, In S

    2015-01-01

    Rhamnolipids were evaluated as biofouling reducing agents in this study. The permeability of the bacterial outer membrane was increased by rhamnolipids while the growth rate of Pseudomonas aeruginosa was not affected. The surface hydrophobicity was increased through the release of lipopolysaccharides and extracellular polymeric substances from the outer cell membrane. Rhamnolipids were evaluated as agents for the prevention and cleaning of biofilms. A high degree of biofilm detachment was observed when the rhamnolipids were used as a cleaning agent. In addition, effective biofilm reduction occurred when rhamnolipids were applied to various species of Gram-negative bacteria isolated from seawater samples. Biofilm reduction using rhamnolipids was comparable to commercially available surfactants. In addition, 20% of the water flux was increased after rhamnolipid treatment (300 μg ml(-1), 6 h exposure time) in a dead-end filtration system. Rhamnolipids appear to have promise as biological agents for reducing membrane biofouling.

  7. Do biological-based strategies hold promise to biofouling control in MBRs?

    KAUST Repository

    Malaeb, Lilian; Le-Clech, Pierre; Vrouwenvelder, Johannes S.; Ayoub, George M.; Saikaly, Pascal

    2013-01-01

    . The reason for the slow advancement in successful control of biofouling is largely attributed to the complex interactions of involved biological compounds and the lack of representative-for-practice experimental approaches to evaluate potential effective

  8. Impaired Performance of Pressure-Retarded Osmosis due to Irreversible Biofouling.

    Science.gov (United States)

    Bar-Zeev, Edo; Perreault, François; Straub, Anthony P; Elimelech, Menachem

    2015-11-03

    Next-generation pressure-retarded osmosis (PRO) approaches aim to harness the energy potential of streams with high salinity differences, such as wastewater effluent and seawater desalination plant brine. In this study, we evaluated biofouling propensity in PRO. Bench-scale experiments were carried out for 24 h using a model wastewater effluent feed solution and simulated seawater desalination brine pressurized to 24 bar. For biofouling tests, wastewater effluent was inoculated with Pseudomonas aeruginosa and artificial seawater desalination plant brine draw solution was seeded with Pseudoalteromonas atlantica. Our results indicate that biological growth in the feed wastewater stream channel severely fouled both the membrane support layer and feed spacer, resulting in ∼50% water flux decline. We also observed an increase in the pumping pressure required to force water through the spacer-filled feed channel, with pressure drop increasing from 6.4±0.8 bar m(-1) to 15.1±2.6 bar m(-1) due to spacer blockage from the developing biofilm. Neither the water flux decline nor the increased pressure drop in the feed channel could be reversed using a pressure-aided osmotic backwash. In contrast, biofouling in the seawater brine draw channel was negligible. Overall, the reduced performance due to water flux decline and increased pumping energy requirements from spacer blockage highlight the serious challenges of using high fouling potential feed sources in PRO, such as secondary wastewater effluent. We conclude that PRO power generation using wastewater effluent and seawater desalination plant brine may become possible only with rigorous pretreatment or new spacer and membrane designs.

  9. Anti-biofouling function of amorphous nano-Ta2O5 coating for VO2-based intelligent windows

    Science.gov (United States)

    Li, Jinhua; Guo, Geyong; Wang, Jiaxing; Zhou, Huaijuan; Shen, Hao; Yeung, Kelvin W. K.

    2017-04-01

    From environmental and health perspectives, the acquisition of a surface anti-biofouling property holds important significance for the usability of VO2 intelligent windows. Herein, we firstly deposited amorphous Ta2O5 nanoparticles on VO2 film by the magnetron sputtering method. It was found that the amorphous nano-Ta2O5 coating possessed a favorable anti-biofouling capability against Pseudomonas aeruginosa as an environmental microorganism model, behind which lay the mechanism that the amorphous nano-Ta2O5 could interrupt the microbial membrane electron transport chain and significantly elevate the intracellular reactive oxygen species (ROS) level. A plausible relationship was established between the anti-biofouling activity and physicochemical nature of amorphous Ta2O5 nanoparticles from the perspective of defect chemistry. ROS-induced oxidative damage gave rise to microbial viability loss. In addition, the amorphous nano-Ta2O5 coating can endow VO2 with favorable cytocompatibility with human skin fibroblasts. This study may provide new insights into understanding the anti-biofouling and antimicrobial actions of amorphous transition metal oxide nanoparticles, which is conducive to expanding their potential applications in environmental fields.

  10. Effect of water temperature on biofouling development in reverse osmosis membrane systems

    KAUST Repository

    Farhat, Nadia; Vrouwenvelder, Johannes S.; van Loosdrecht, Mark C.M.; Bucs, Szilard; Staal, Marc

    2016-01-01

    temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high

  11. Biofouling of reverse-osmosis membranes during tertiary wastewater desalination: microbial community composition.

    Science.gov (United States)

    Al Ashhab, Ashraf; Herzberg, Moshe; Gillor, Osnat

    2014-03-01

    Reverse-osmosis (RO) desalination is frequently used for the production of high-quality water from tertiary treated wastewater (TTWW). However, the RO desalination process is often hampered by biofouling, including membrane conditioning, microbial adhesion, and biofilm growth. The vast majority of biofilm exploration concentrated on the role of bacteria in biofouling neglecting additional microbial contributors, i.e., fungi and archaea. To better understand the RO biofouling process, bacterial, archaeal and fungal diversity was characterized in a laboratory-scale RO desalination plant exploring the TTWW (RO feed), the RO membrane and the RO feed tube biofilms. We sequenced 77,400 fragments of the ribosome small subunit-encoding gene (16S and 18S rRNA) to identify the microbial community members in these matrices. Our results suggest that the bacterial, archaeal but not fungal community significantly differ from the RO membrane biofouling layer to the feedwater and tube biofilm (P < 0.01). Moreover, the RO membrane supported a more diverse community compared to the communities monitored in the feedwater and the biofilm attached to the RO feedwater tube. The tube biofilm was dominated by Actinobacteria (91.2 ± 4.6%), while the Proteobacteria phylum dominated the feedwater and RO membrane (at relative abundance of 92.3 ± 4.4% and 71.5 ± 8.3%, respectively), albeit comprising different members. The archaea communities were dominated by Crenarchaeota (53.0 ± 6.9%, 32.5 ± 7.2% and 69%, respectively) and Euryarchaeota (43.3 ± 6.3%, 23.2 ± 4.8% and 24%, respectively) in all three matrices, though the communities' composition differed. But the fungal communities composition was similar in all matrices, dominated by Ascomycota (97.6 ± 2.7%). Our results suggest that the RO membrane is a selective surface, supporting unique bacterial, and to a lesser extent archaeal communities, yet it does not select for a fungal community. Copyright © 2013

  12. Chemical composition influence of cement based mortars on algal biofouling

    Science.gov (United States)

    Estelle, Dalod; Alexandre, Govin; Philippe, Grosseau; Christine, Lors; René, Guyonnet; Denis, Damidot

    2013-04-01

    The main cause of building-facade biodegradation is the growth of microorganisms. This phenomenon depends on several parameters such as the geographical situation, the environmental conditions and the surface state of the substrate. Several researches have been devoted to the study of the effect of porosity and roughness on the biofouling of stones and mortars. However, none of them have addressed the influence of the mortar chemistry on the microorganism growth kinetic. The main objective of this study is to highlight the influence of the mortar chemistry in relationship with its physical properties on biological weathering. Earlier work showed a good resistance of Calcium Aluminate Cements to biodeterioration by acidogenic bacteria (Thiobacillus) and fungi (Alternaria alternata, Aspergillus Niger and Coniosporium uncinatum). In order to characterize the influence of the mortar chemistry on biofouling, two Portland cements and two alumina cements are used. Among micro-organisms able to grow, green algae are most involved in the aesthetic deterioration of facades. Indeed, they can colonize any type of media and can be a source of nutrients for other micro-organisms such as fungi. The green algae Klebsormidium flaccidum is chosen because of its representativeness. It is indeed the species the most frequently identified and isolated from samples taken on sites. The biofouling kinetic is followed on samples exposed outdoor and on samples tested in a laboratory bench which consists in spraying an algae culture on mortar specimens. The results obtained by in situ trials are compared with the results obtained on the laboratory bench. The microorganism growth kinetic is measured by image analysis. To improve the detection of algae on the surface of the cementitious samples, the raw image is converted in the YIQ color space. Y, I and Q correspond respectively to luminance, in-phase, and quadrature. On the Q channel, the areas covered by algae and the areas of clean mortar

  13. Biofouling Prevention of Ancient Brick Surfaces by TiO2-Based Nano-Coatings

    Directory of Open Access Journals (Sweden)

    Lorenzo Graziani

    2015-07-01

    Full Text Available Brick constitutes a significant part of the construction materials used in historic buildings around the world. This material was used in Architectural Heritage for structural scope, and even for building envelopes. Thus, components made of clay brick were subjected to weathering for a long time, and this causes their deterioration. One of the most important causes for deterioration is biodeterioration caused by algae and cyanobacteria. It compromises the aesthetical properties, and, at a later stage, the integrity of the elements. In fact, traditional products used for the remediation/prevention of biofouling do not ensure long-term protection, and they need re-application over time. The use of nanotechnology, especially the use of photocatalytic products for the prevention of organic contamination of building façades is increasing. In this study, TiO2-based photocatalytic nano-coatings were applied to ancient brick, and its efficiency towards biofouling was studied. A composed suspension of algae and cyanobacteria was sprinkled on the bricks’ surface for a duration of twelve weeks. Digital Image Analysis and colorimetric measurements were carried out to evaluate algal growth on specimens’ surfaces. Results show that photocatalytic nano-coating was able to inhibit biofouling on bricks’ surfaces. In addition, substrata (their porosity and roughness clearly influences the adhesion of algal cells.

  14. Modeling the effect of spacers and biofouling on forward osmosis performance

    KAUST Repository

    Mosqueira Santillán, María José

    2014-11-01

    Currently, the most utilized desalination technology is reverse osmosis (RO), where a membrane is used as a physical barrier to separate the salts from the seawater, using high hydraulic pressure as driving force. A major problem in RO systems is biofouling, caused by severe growth of bacterial biofilms. Both, the need of an external energy input, as well as biofouling, impose a high cost on RO operation. Forward osmosis (FO) is an alternative membrane process that uses an osmotic pressure difference as driving force. FO uses a concentrated draw solution to generate high osmotic pressure, which extracts water across a semi permeable membrane from a feed solution. One of the main advantages of FO is the limited amount of external energy required to extract water from the feed solution. The objective of this research is the assessment of the impact of spacers, separating the membrane sheets, and biofouling on the FO system performance. This type of studies allow the optimization of membrane devices and operational conditions. For this, a two dimensional numerical model for FO systems was developed using computational fluid dynamics (CFD). This model allowed the evaluation of the impact of (i) spacers and (ii) biofilm, and (iii) the combined impact of spacers and biofilm on the performance of FO systems. The results obtained showed that the presence of spacers improved the performance of FO systems. Cavity configuration spacer gave the higher water flux across the membrane in clean systems; whereas for biofouled systems, the submerged configuration showed a better performance. In absence of spacers, the thickness or amount of biofilm is inversely proportional with the water flux. Furthermore, membrane surface coverage of the biofilm is more important than the amount of biofilm in terms of the impact on the performance. The numerical model can be adapted with other parameters (e.g. membrane and spacer thickness, feed and draw solution, solution concentration, etc.) to

  15. Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: A novel platform for eco-friendly biofouling mitigation

    NARCIS (Netherlands)

    Wibisono, Y.; Yandi, Wetra; Golabi, Mohsen; Nugraha, Roni; Cornelissen, Emile R.; Kemperman, Antonius J.B.; Ederth, Thomas; Nijmeijer, Dorothea C.

    2015-01-01

    Biofouling is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a hydrogel-coated feed spacer and two-phase flow cleaning. Neutral

  16. Effect of water temperature on biofouling development in reverse osmosis membrane systems

    KAUST Repository

    Farhat, Nadia

    2016-07-14

    Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water.

  17. Bacterial communities associated with biofouling materials used in bench-scale hydrocarbon bioremediation.

    Science.gov (United States)

    Al-Mailem, Dina; Kansour, Mayada; Radwan, Samir

    2015-03-01

    Biofouling material samples from the Arabian (Persian) Gulf, used as inocula in batch cultures, brought about crude oil and pure-hydrocarbon removal in a mineral medium. Without any added nitrogen fertilizers, the hydrocarbon-removal values were between about 10 and 50 %. Fertilization with NaNO3 alone or together with a mixture of the vitamins thiamine, pyridoxine, vitamin B12, biotin, riboflavin, and folic acid increased the hydrocarbon-removal values, to reach 90 %. Biofouling material samples harbored total bacteria in the magnitude of 10(7) cells g(-1), about 25 % of which were hydrocarbonoclastic. These numbers were enhanced by NaNO3 and vitamin amendment. The culture-independent analysis of the total bacterioflora revealed the predominance of the gammaproteobacterial genera Marinobacter, Acinetobacter, and Alcanivorax, the Flavobacteriia, Flavobacterium, Gaetbulibacter, and Owenweeksia, and the Alphaproteobacteria Tistrella, Zavarzinia, and others. Most of those bacteria are hydrocarbonoclastic. Culture-dependent analysis of hydrocarbonoclastic bacteria revealed that Marinobacter hydrocarbonoclasticus, Dietzia maris, and Gordonia bronchialis predominated in the fouling materials. In addition, each material had several more-specific hydrocarbonoclastic species, whose frequencies were enhanced by NaNO3 and vitamin fertilization. The same samples of fouling materials were used in four successive crude-oil-removal cycles without any dramatic loss of their hydrocarbon-removal potential nor of their associated hydrocarbonoclastic bacteria. In the fifth cycle, the oil-removal value was reduced by about 50 % in only one of the studied samples. This highlights how firmly biofouling materials were immobilizing the hydrocarbonoclastic bacteria.

  18. Bioinspiration-the solution for biofouling control?

    International Nuclear Information System (INIS)

    Ralston, Emily; Swain, Geoffrey

    2009-01-01

    Most surfaces in the marine environment, both biotic and abiotic, are subject to biofouling. This has significant consequences for the safe and efficient conduct of marine activities. There is a pressing need to develop environmentally and economically acceptable methods to control the problem. In nature most plants and animals have evolved techniques that prevent or limit the process of fouling. These include chemical, physical, mechanical and behavioral responses. This paper reviews the knowledge with respect to natural antifouling methods, discusses similarities between natural mechanisms and existing antifouling technology and identifies potential future bioinspired approaches for the prevention of hull fouling specifically as they apply to US Navy requirements

  19. It's a wrap: encapsulation as a management tool for marine biofouling.

    Science.gov (United States)

    Atalah, Javier; Brook, Rosemary; Cahill, Patrick; Fletcher, Lauren M; Hopkins, Grant A

    2016-01-01

    Encapsulation of fouled structures is an effective tool for countering incursions by non-indigenous biofoulers. However, guidelines for the implementation of encapsulation treatments are yet to be established. This study evaluated the effects of temperature, biomass, community composition, treatment duration and the biocide acetic acid on biofoulers. In laboratory trials using the model organisms Ciona spp. and Mytilus galloprovincialis, increasing the temperature or biomass speeded up the development of a toxic environment. Total mortality for Ciona spp. occurred within 72 and 24 h at 10 and 19°C, respectively. M. galloprovincialis survived up to 18 days, with high biomass increasing mortality at 10°C only. In a field study, three-month-old and four-year-old communities were encapsulated with and without acetic acid. Mortality took up to 10 days for communities encapsulated without acetic acid, compared to 48 h with acetic acid. The insights gained from this study will be useful in developing standardised encapsulation protocols.

  20. Vessel generator noise as a settlement cue for marine biofouling species.

    Science.gov (United States)

    McDonald, J I; Wilkens, S L; Stanley, J A; Jeffs, A G

    2014-01-01

    Underwater noise is increasing globally, largely due to increased vessel numbers and international ocean trade. Vessels are also a major vector for translocation of non-indigenous marine species which can have serious implications for biosecurity. The possibility that underwater noise from fishing vessels may promote settlement of biofouling on hulls was investigated for the ascidian Ciona intestinalis. Spatial differences in biofouling appear to be correlated with spatial differences in the intensity and frequency of the noise emitted by the vessel's generator. This correlation was confirmed in laboratory experiments where C. intestinalis larvae showed significantly faster settlement and metamorphosis when exposed to the underwater noise produced by the vessel generator. Larval survival rates were also significantly higher in treatments exposed to vessel generator noise. Enhanced settlement attributable to vessel generator noise may indicate that vessels not only provide a suitable fouling substratum, but vessels running generators may be attracting larvae and enhancing their survival and growth.

  1. Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: a novel platform for eco-friendly biofouling mitigation.

    Science.gov (United States)

    Wibisono, Yusuf; Yandi, Wetra; Golabi, Mohsen; Nugraha, Roni; Cornelissen, Emile R; Kemperman, Antoine J B; Ederth, Thomas; Nijmeijer, Kitty

    2015-03-15

    Biofouling is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a hydrogel-coated feed spacer and two-phase flow cleaning. Neutral (polyHEMA-co-PEG10MA), cationic (polyDMAEMA) and anionic (polySPMA) hydrogels have been successfully grafted onto polypropylene (PP) feed spacers via plasma-mediated UV-polymerization. These coatings maintained their chemical stability after 7 days incubation in neutral (pH 7), acidic (pH 5) and basic (pH 9) environments. Anti-biofouling properties of these coatings were evaluated by Escherichia coli attachment assay and nanofiltration experiments at a TMP of 600 kPag using tap water with additional nutrients as feed and by using optical coherence tomography. Especially the anionic polySPMA-coated PP feed spacer shows reduced attachment of E. coli and biofouling in the spacer-filled narrow channels resulting in delayed biofilm growth. Employing this highly hydrophilic coating during removal of biofouling by two-phase flow cleaning also showed enhanced cleaning efficiency, feed channel pressure drop and flux recoveries. The strong hydrophilic nature and the presence of negative charge on polySPMA are most probably responsible for the improved antifouling behavior. A combination of polySPMA-coated PP feed spacers and two-phase flow cleaning therefore is promising and an environmentally friendly approach to control biofouling in NF/RO systems employing spiral-wound membrane modules. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Spatial heterogeneity of biofouling under different cross-flow velocities in reverse osmosis membrane systems

    KAUST Repository

    Farhat, Nadia

    2016-09-06

    The spatially heterogeneous distribution of biofouling in spiral wound membrane systems restricts (i) the water distribution over the membrane surface and therefore (ii) the membrane-based water treatment. The objective of the study was to assess the spatial heterogeneity of biofilm development over the membrane fouling simulator (MFS) length (inlet and outlet part) at three different cross-flow velocities (0.08, 0.12 and 0.16 m/s). The MFS contained sheets of membrane and feed spacer and simulated the first 0.20 m of spiral-wound membrane modules where biofouling accumulates the most in practice. In-situ non-destructive oxygen imaging using planar optodes was applied to determine the biofilm spatially resolved activity and heterogeneity.

  3. Application of fluorescently labelled lectins for the study of polysaccharides in biofilms with a focus on biofouling of nanofiltration membranes

    Directory of Open Access Journals (Sweden)

    Patrick Di Martino

    2016-07-01

    Full Text Available The biofilm state is the dominant microbial lifestyle in nature. A biofilm can be defined as cells organised as microcolonies embedded in an organic polymer matrix of microbial origin living at an interface between two different liquids, air and liquid, or solid and liquid. The biofilm matrix is made of extracellular polymeric substances, polysaccharides being considered as the major structural components of the matrix. Fluorescently labelled lectins have been widely used to stain microbial extracellular glycoconjugates in natural and artificial environments, and to study specific bacterial species or highly complex environments. Biofilm development at the membrane surface conducting to biofouling is one of the major problems encountered during drinking water production by filtration. Biofouling affects the durability and effectiveness of filtration membranes. Biofouling can be reduced by pretreatments in order to control two key parameters of water, the bioavailable organic matter concentration and the concentration of live bacteria. Nanofiltration (NF is a high technology process particularly suited to the treatment of surface waters to produce drinking water that is highly sensitive to biofouling. The development of strategies for fouling prevention and control requires characterizing the fouling material composition and organisation before and after NF membrane cleaning. The aim of this review is to present basics of biofilm analyses after staining with fluorescently labelled lectins and to focus on the use of fluorescent lectins and confocal laser scanning microscopy to analyse NF membrane biofouling.

  4. Performance assessment of oxidants as a biocide for biofouling control in industrial seawater cooling towers

    KAUST Repository

    Al-Bloushi, Mohammed; Saththasivam, Jayaprakash; Jeong, Sanghyun; Amy, Gary L.; Leiknes, TorOve

    2017-01-01

    Biofouling can significantly hamper the efficiency of seawater cooling towers. The aim of this study was to investigate the effectiveness of alternative oxidants (i.e. ozone (O3) and chlorine dioxide (ClO2)) comparing with commonly being used chlorine in biofouling control. Effects of cycle of concentration, temperature and oxidant dosage along with residual decay and kinetics were studied. Even at lower oxidant dosage (total residual oxidant equivalent=0.1mg/L Cl2), ClO2 showed a better disinfection effect compared to chlorine and O3. Results of bench-scale studies will be helpful in the selection of appropriate oxidant for seawater cooling tower operation.

  5. Performance assessment of oxidants as a biocide for biofouling control in industrial seawater cooling towers

    KAUST Repository

    Al-Bloushi, Mohammed

    2017-10-14

    Biofouling can significantly hamper the efficiency of seawater cooling towers. The aim of this study was to investigate the effectiveness of alternative oxidants (i.e. ozone (O3) and chlorine dioxide (ClO2)) comparing with commonly being used chlorine in biofouling control. Effects of cycle of concentration, temperature and oxidant dosage along with residual decay and kinetics were studied. Even at lower oxidant dosage (total residual oxidant equivalent=0.1mg/L Cl2), ClO2 showed a better disinfection effect compared to chlorine and O3. Results of bench-scale studies will be helpful in the selection of appropriate oxidant for seawater cooling tower operation.

  6. Application of DBNPA dosage for biofouling control in spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber; Pinel, I.; Prest, E.I.; Bucs, Szilard; van Loosdrecht, M.C.M.; Kruithof, J.C.; Vrouwenvelder, Johannes S.

    2017-01-01

    in MFS was quantified by adenosine triphosphate (ATP) and total organic carbon (TOC) analysis. Continuous dosage of DBNPA (1 mg/L) prevented pressure drop increase and biofilm accumulation in the MFSs during a run time of 7 d, showing that biofouling can

  7. Biofouling in capillary and spiral wound membranes facilitated by marine algal bloom

    NARCIS (Netherlands)

    Villacorte, L.O.; Ekowati, Y.; Calix-Ponce, H.N.; Kisielius, V.; Kleijn, J.M.; Vrouwenvelder, J.S.; Schippers, J.C.; Kennedy, M.D.

    2017-01-01

    Algal-derived organic matter (AOM), particularly transparent exopolymer particles, has been suspected to facilitate biofilm development in membrane systems (e.g., seawater reverse osmosis). This study demonstrates the possible role of AOM on biofouling in membrane systems affected by marine algal

  8. In-situ Non-destructive Studies on Biofouling Processes in Reverse Osmosis Membrane Systems

    KAUST Repository

    Farhat, Nadia

    2016-01-01

    biofouling detection methods are mainly destructive, such as membrane autopsies, where biofilm samples can be contaminated, damaged and resulting in biofilm structural changes. The objective of this study was to test whether transparent luminescent planar

  9. Biofouling on Reservoir in Sea Water

    Science.gov (United States)

    Yoon, H.; Eom, C.; Kong, M.; Park, Y.; Chung, K.; Kim, B.

    2011-12-01

    The organisms which take part in marine biofouling are primarily the attached or sessile forms occurring naturally in the shallower water along the coast [1]. This is mainly because only those organisms with the ability to adapt to the new situations created by man can adhere firmly enough to avoid being washed off. Chemical and microbiological characteristics of the fouling biofilms developed on various surfaces in contact with the seawater were made. The microbial compositions of the biofilm communities formed on the reservoir polymer surfaces were tested for. The quantities of the diverse microorganisms in the biofilm samples developed on the prohibiting polymer reservoir surface were larger when there was no concern about materials for special selection for fouling. To confirm microbial and formation of biofilm on adsorbents was done CLSM (Multi-photon Confocal Laser Scanning Microscope system) analysis. Microbial identified using 16S rRNA. Experiment results, five species which are Vibrio sp., Pseudoalteromonas, Marinomonas, Sulfitobacter, and Alteromonas discovered to reservoir formed biofouling. There are some microorganism cause fouling and there are the others control fouling. The experimental results offered new specific information, concerning the problems in the application of new material as well as surface coating such as anti-fouling coatings. They showed the important role microbial activity in fouling and corrosion of the surfaces in contact with the any seawater. Acknowledgement : This research was supported by the national research project titled "The Development of Technology for Extraction of Resources Dissolved in Seawater" of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Land, Transport and Maritime Affairs. References [1] M. Y. Diego, K. Soren, and D. J. Kim. Prog. Org. Coat. 50, (2004) p.75-104.

  10. Biomimicking micropatterned surfaces and their effect on marine biofouling.

    Science.gov (United States)

    Brzozowska, Agata M; Parra-Velandia, Fernando J; Quintana, Robert; Xiaoying, Zhu; Lee, Serina S C; Chin-Sing, Lim; Jańczewski, Dominik; Teo, Serena L-M; Vancso, Julius G

    2014-08-05

    When synthetic materials are submerged in marine environments, dissolved matter and marine organisms attach to their surfaces by a process known as marine fouling. This phenomenon may lead to diminished material performance with detrimental consequences. Bioinspired surface patterning and chemical surface modifications present promising approaches to the design of novel functional surfaces that can prevent biofouling phenomena. In this study, we report the synergistic effects of surface patterns, inspired by the marine decapod crab Myomenippe hardwickii in combination with chemical surface modifications toward suppressing marine fouling. M. hardwickii is known to maintain a relatively clean carapace although the species occurs in biofouling communities of tropical shallow subtidal coastal waters. Following the surface analysis of selected specimens, we designed hierarchical surface microtopographies that replicate the critical features observed on the crustacean surface. The micropatterned surfaces were modified with zwitterionic polymer brushes or with layer-by-layer deposited polyelectrolyte multilayers to enhance their antifouling and/or fouling-release potential. Chemically modified and unmodified micropatterned surfaces were subjected to extensive fouling tests, including laboratory assays against barnacle settlement and algae adhesion, and field static immersion tests. The results show a statistically significant reduction in settlement on the micropatterned surfaces as well as a synergistic effect when the microtopographies are combined with grafted polymer chains.

  11. Influence of the chemical composition, heat and surface treatment in the biofouling of austenitic stainless steels

    International Nuclear Information System (INIS)

    Sarro, M. I.; Aleman, O.; Moreno, D. A.; Roso, M.; Ranninger, C.

    2004-01-01

    The main objective of this study was to analyse the biofouling processes in the kinds of stainless steels used normally in industry (UNS S30400, UNS S30403 and UNS S31600), with different surface treatments after grinding and polishing. The study was developed using two microscopy techniques. Scanning Electron Microscopy (SEM was used to evaluate the microorganisms distribution in the materials, and Epi fluorescence Microscopy was used to evaluate the viability of cells in the biofilm. The results revealed the influence of the material, heat treatment, surface treatment and roughness in the biofouling processes in the stainless steel assays. (Author) 33 refs

  12. Effect of water temperature on biofouling development in reverse osmosis membrane systems.

    Science.gov (United States)

    Farhat, N M; Vrouwenvelder, J S; Van Loosdrecht, M C M; Bucs, Sz S; Staal, M

    2016-10-15

    Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Triclosan-immobilized polyamide thin film composite membranes with enhanced biofouling resistance

    Science.gov (United States)

    Park, Sang-Hee; Hwang, Seon Oh; Kim, Taek-Seung; Cho, Arah; Kwon, Soon Jin; Kim, Kyoung Taek; Park, Hee-Deung; Lee, Jung-Hyun

    2018-06-01

    We report on a strategy to improve biofouling resistance of a polyamide (PA) thin-film composite (TFC) reverse osmosis (RO) membrane via chemically immobilizing triclosan (TC), known as a common organic biocide, on its surface. To facilitate covalent attachment of TC on the membrane surface, TC was functionalized with amine moiety to prepare aminopropyl TC. Then, the TC-immobilized TFC (TFC-TC) membranes were fabricated through a one-step amide formation reaction between amine groups of aminopropyl TC and acyl chloride groups present on the PA membrane surface, which was confirmed by high-resolution XPS. Strong stability of the immobilized TC was also confirmed by a hydraulic washing test. Although the TFC-TC membrane showed slightly reduced separation performance compared to the pristine control, it still maintained a satisfactory RO performance level. Importantly, the TFC-TC membrane exhibited excellent antibacterial activity against both gram negative (E. coli and P. aeruginosa) and gram positive (S. aureus) bacteria along with greatly enhanced resistance to biofilm formation. Our immobilization approach offers a robust and relatively benign strategy to control biofouling of functional surfaces, films and membranes.

  14. Semisubmersible oil platforms: understudied and potentially major vectors of biofouling-mediated invasions.

    Science.gov (United States)

    Yeo, Darren C J; Ahyong, Shane T; Lodge, David M; Ng, Peter K L; Naruse, Tohru; Lane, David J W

    2010-01-01

    Biofouling has long been recognised as a major pathway for the introduction of non-indigenous species. This study records the decapods and stomatopod crustaceans fouling a semisubmersible oil platform dry docked for hull cleaning in Jurong Port, Singapore. Of the 25 species of decapods identified, 13 were non-indigenous and represent new records to Singapore waters. Of these, the crabs Glabropilumnus seminudus and Carupa tenuipes are known to be invasive in other parts of the world. The stomatopod, Gonodactylaceus randalli, is the first mantis shrimp recorded in a biofouling community. The richness and diversity of this fouling community, consisting of many vagile species, highlights the difference between platforms and ships. With the expansion of maritime oil and gas exploration, the threat posed by an expanded fleet of semisubmersible oil platforms translocating non-indigenous fouling communities across biogeographical boundaries is very serious. Scientists, policy-makers, and stakeholders should turn their attention to this growing problem.

  15. Mini-review: Inhibition of biofouling by marine microorganisms.

    Science.gov (United States)

    Dobretsov, Sergey; Abed, Raeid M M; Teplitski, Max

    2013-01-01

    Any natural or artificial substratum exposed to seawater is quickly fouled by marine microorganisms and later by macrofouling species. Microfouling organisms on the surface of a substratum form heterogenic biofilms, which are composed of multiple species of heterotrophic bacteria, cyanobacteria, diatoms, protozoa and fungi. Biofilms on artificial structures create serious problems for industries worldwide, with effects including an increase in drag force and metal corrosion as well as a reduction in heat transfer efficiency. Additionally, microorganisms produce chemical compounds that may induce or inhibit settlement and growth of other fouling organisms. Since the last review by the first author on inhibition of biofouling by marine microbes in 2006, significant progress has been made in the field. Several antimicrobial, antialgal and antilarval compounds have been isolated from heterotrophic marine bacteria, cyanobacteria and fungi. Some of these compounds have multiple bioactivities. Microorganisms are able to disrupt biofilms by inhibition of bacterial signalling and production of enzymes that degrade bacterial signals and polymers. Epibiotic microorganisms associated with marine algae and invertebrates have a high antifouling (AF) potential, which can be used to solve biofouling problems in industry. However, more information about the production of AF compounds by marine microorganisms in situ and their mechanisms of action needs to be obtained. This review focuses on the AF activity of marine heterotrophic bacteria, cyanobacteria and fungi and covers publications from 2006 up to the end of 2012.

  16. Biofouling of reverse osmosis membranes used in river water purification for drinking purposes: analysis of microbial populations.

    Science.gov (United States)

    Chiellini, Carolina; Iannelli, Renato; Modeo, Letizia; Bianchi, Veronica; Petroni, Giulio

    2012-01-01

    Biofouling in water treatment processes represents one of the most frequent causes of plant performance decline. Investigation of clogged membranes (reverse osmosis membranes, microfiltration membranes and ultrafiltration membranes) is generally performed on fresh membranes. In the present study, a multidisciplinary autopsy of a reverse osmosis membrane (ROM) was conducted. The membrane, which was used in sulfate-rich river water purification for drinking purposes, had become inoperative after 6 months because of biofouling and was later stored for 18 months in dry conditions before analysis. SSU rRNA gene library construction, clone sequencing, T-RFLP, light microscope, and scanning electron microscope (SEM) observations were used to identify the microorganisms present on the membrane and possibly responsible for biofouling at the time of removal. The microorganisms were mainly represented by bacteria belonging to the phylum Actinobacteria and by a single protozoan species belonging to the Lobosea group. The microbiological analysis was interpreted in the context of the treatment plant operations to hypothesize as to the possible mechanisms used by microorganisms to enter the plant and colonize the ROM surface.

  17. In situ observation of the growth of biofouling layer in osmotic membrane bioreactors by multiple fluorescence labeling and confocal laser scanning microscopy.

    Science.gov (United States)

    Yuan, Bo; Wang, Xinhua; Tang, Chuyang; Li, Xiufen; Yu, Guanghui

    2015-05-15

    Since the concept of the osmotic membrane bioreactor (OMBR) was introduced in 2008, it has attracted growing interests for its potential applications in wastewater treatment and reclamation; however, the fouling mechanisms of forward osmosis (FO) membrane especially the development of biofouling layer in the OMBR are not yet clear. Here, the fouled FO membranes were obtained from the OMBRs on days 3, 8 and 25 in sequence, and then the structure and growing rule of the biofouling layer formed on the FO membrane samples were in-situ characterized by multiple fluorescence labeling and confocal laser scanning microscopy (CLSM). CLSM images indicated that the variations in abundance and distribution of polysaccharides, proteins and microorganisms in the biofouling layer during the operation of OMBRs were significantly different. Before the 8th day, their biovolume dramatically increased. Subsequently, the biovolumes of β-d-glucopyranose polysaccharides and proteins continued increasing and leveled off after 8 days, respectively, while the biovolumes of α-d-glucopyranose polysaccharides and microorganisms decreased. Extracellular polymeric substances (EPS) played a significant role in the formation and growth of biofouling layer, while the microorganisms were seldom detected on the upper fouling layer after 3 days. Based on the results obtained in this study, the growth of biofouling layer on the FO membrane surface in the OMBR could be divided into three stages. Initially, EPS was firstly deposited on the FO membrane surface, and then microorganisms associated with EPS located in the initial depositing layer to form clusters. After that, the dramatic increase of the clusters of EPS and microorganisms resulted in the quick growth of biofouling layer during the flux decline of the OMBR. However, when the water flux became stable in the OMBR, some microorganisms and EPS would be detached from the FO membrane surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Impact of reverse nutrient diffusion on membrane biofouling in fertilizer-drawn forward osmosis

    KAUST Repository

    Li, Sheng; Kim, Youngjin; Chekli, Laura; Phuntsho, Sherub; Shon, Ho Kyong; Leiknes, TorOve; Ghaffour, NorEddine

    2017-01-01

    Biofouling in fertilizer-drawn forward osmosis (FDFO) for water reuse was investigated by spiking pure bacteria species Pseudomonas aeruginosa PAO1+GFP and using three different fertilizers KNO3, KCl and KH2PO4 as draw solutions. The performance

  19. Combined impact of quorum quenching and backwashing on biofouling control in a semi-pilot scale mbr treating real wastewater

    International Nuclear Information System (INIS)

    Hasnain, G.; Khan, S.J.; Arshad, M.Z.; Abdullah, H.Y.

    2017-01-01

    This study demonstrates the combined effect of quorum quenching (QQ) and backwashing on biofouling control in MBR treating real wastewater. The quorum quenching mechanism is an emerging biological technique using Rhodococcus sp. entrapped in polymer coated sodium alginate beads whereas, backwashing is a distinguished physical technique for biofouling control. Two parallel semi-pilot scale MBRs i.e., QQ-MBR (quorum quenching MBR) with cell-entrapping beads (CEBs) and C-MBR (conventional MBR) with vacant CEBs at 0.5% effective volume of the bioreactor, were monitored for comparative performance evaluation. In the first phase, both the MBRs were operated without backwashing having operational cycle of eight min filtration and two min relaxation and in the second phase; MBRs were operated with backwashing having operation cycle of eight min filtration, one min relaxation and one min backwashing. QQ-MBR-with backwashing exhibited greater biofouling control capability and elongated filtration duration with respect to QQ-MBR without backwashing. Comparatively less soluble EPS concentrations were detected in QQ-MBR as compare to C-MBR in both modes of operation while backwashing contributed to retard the rapid increase in trans-membrane pressure (TMP) also known as TMP jump. Study reveals the novelty of successful application of combined influence of permeate backflushing technique and QQ (anti-biofouling) strategy in MBR and potential use for full scale applications. (author)

  20. Investigations into the Settlement and Attachment of Biofouling Marine Invertebrates

    Science.gov (United States)

    2015-12-17

    attachment of biofouling marine invertebrates 5a. CONTRACT NUMBER N00014-12-1 -0432 5b. GRANT NUMBER n/a 5c. PROGRAM ELEMENT NUMBER n/a 6...larval settlement in a variety of marine invertebrate species, including B. neritina. Light also inhibits B. neritina larval settlement, yet the...underlying mechanisms by which light and adrenergic compounds exert their effects on larvae are largely unknown. Octopamine is considered the invertebrate

  1. Application of monochloramine for wastewater reuse: Effect on biostability during transport and biofouling in RO membranes

    KAUST Repository

    Farhat, Nadia

    2018-02-23

    The rising demand for clean and safe water has increased the interest in advanced wastewater treatment and reuse. Reverse osmosis (RO) can provide reliable and high-quality water from treated wastewater. Biofouling inevitably occurs, certainly with wastewater effluents, resulting in RO performance decline and operational problems. Chlorination of feed water has been commonly applied to limit biological growth. However, chlorine use may lead to a loss of membrane integrity of RO systems. In this study the potential of monochloramine as an alternative for chlorine was studied by (i) evaluating the biological stability of a full-scale wastewater membrane bioreactor (MBR) effluent during transport over 13 km to a full-scale RO plant and (ii) assessing the biofouling control potential in membrane fouling simulator (MFS) and pilot-scale RO installation. Microbial water analysis was performed on samples taken at several locations in the full-scale water reuse system (MBR effluent, during transport, and at the RO inlet and outlet) using a suite of tools including heterotrophic plate counts (HPC), adenosine triphosphate (ATP), flow cytometry (FCM), and 16 S rRNA gene pyrosequencing. Growth potential tests were used to evaluate the effect of monochloramine presence and absence on bacterial growth. Results showed limited changes in the microbial water quality in the presence of monochloramine. MFS studies showed that membrane biofouling could be effectively repressed by monochloramine over prolonged time periods. The normalized salt passage in a pilot RO system with monochloramine dosage was constant over a one year period (data of last 130 days presented), demonstrating that no membrane damage occurred. From this study, it can be concluded that monochloramine dosage in wastewater applications is effective in controlling biofouling in RO systems and maintaining a monochloramine residual during water transport provides biologically stable water.

  2. Effect of microbial community structure on organic removal and biofouling in membrane adsorption bioreactor used in seawater pretreatment

    KAUST Repository

    Jeong, Sanghyun; Cho, Kyungjin; Bae, Hyokwan; Keshvardoust, Pejhman; Rice, Scott A.; Vigneswaran, Saravanamuthu; Lee, Seockheon; Leiknes, TorOve

    2016-01-01

    Membrane bioreactors (MBRs) were operated on-site for 56 d with different powdered activated carbon (PAC) dosages of 0, 1.5 and 5.0 g/L to pretreat seawater for reverse osmosis desalination. It was hypothesized that PAC would stimulate adsorption and biological degradation of organic compounds. The microbial communities responsible for biofouling on microfiltration (MF) membranes and biological organic removal in MBR were assessed using terminal restriction fragment length polymorphism fingerprinting and 454-pyrosequencing. The PAC addition improved assimilable organic carbon removal (53-59%), and resulted in reduced biofouling development on MF (> 50%) with only a marginal development in trans-membrane pressure. Interestingly, the bacterial community composition was significantly differentiated by the PAC addition. Cyanobacterium, Pelagibaca and Maricoccus were dominant in the PAC-free conditions, while Thiothrix and Sphingomonas were presumably responsible for the better reactor performances in PAC-added conditions. In contrast, the archaeal communities were consistent with predominance of Candidatus Nitrosopumilus. These data therefore show that the addition of PAC can improve MBR performance by developing different bacterial species, controlling AOC and associated biofouling on the membranes.

  3. Effect of microbial community structure on organic removal and biofouling in membrane adsorption bioreactor used in seawater pretreatment

    KAUST Repository

    Jeong, Sanghyun

    2016-03-03

    Membrane bioreactors (MBRs) were operated on-site for 56 d with different powdered activated carbon (PAC) dosages of 0, 1.5 and 5.0 g/L to pretreat seawater for reverse osmosis desalination. It was hypothesized that PAC would stimulate adsorption and biological degradation of organic compounds. The microbial communities responsible for biofouling on microfiltration (MF) membranes and biological organic removal in MBR were assessed using terminal restriction fragment length polymorphism fingerprinting and 454-pyrosequencing. The PAC addition improved assimilable organic carbon removal (53-59%), and resulted in reduced biofouling development on MF (> 50%) with only a marginal development in trans-membrane pressure. Interestingly, the bacterial community composition was significantly differentiated by the PAC addition. Cyanobacterium, Pelagibaca and Maricoccus were dominant in the PAC-free conditions, while Thiothrix and Sphingomonas were presumably responsible for the better reactor performances in PAC-added conditions. In contrast, the archaeal communities were consistent with predominance of Candidatus Nitrosopumilus. These data therefore show that the addition of PAC can improve MBR performance by developing different bacterial species, controlling AOC and associated biofouling on the membranes.

  4. Effect of organic on chemical oxidation for biofouling control in pilot-scale seawater cooling towers

    KAUST Repository

    Al-Bloushi, Mohammed

    2017-09-14

    Due to the scarcity of potable water in many regions of the world, the demand for seawater as an alternative evaporative cooling medium in cooling towers (CTs) has increased significantly in recent years. Seawater make-up in CTs is deemed the most feasible because of its unlimited supply in the coastal areas of Gulf and Red Sea. However, the seawater CTs have higher challenges greatly mitigating their performances because it is an open system where biofouling and bio-corrosion occurring within the fillers and piping of recirculation systems. Their pilot-scale CTs were constructed to assess the performance of three types of oxidizing biocides or oxidants, namely chlorine, chlorine dioxide (ClO2) and ozone, for biofouling control. The test results showed that the addition of organic (5mg/L of methanol (MeOH)) increased the bacterial growth in CT basin. All oxidants were effective in keeping the microbial growth to the minimum. Oxidation increased the oxidation-reduction potential (ORP) level from 270 to 600mV. Total residual oxidant (TRO) was increased with oxidation but it was slightly increased with organic addition. Other parameters including pH, dissolved oxygen (DO), conductivity levels were not changed. However, higher formation of disinfection by-products (DBPs) was detected with chlorination and ozonation. This indicates the organic level should be limited in the oxidation for biofouling control in seawater CTs.

  5. Effect of organic on chemical oxidation for biofouling control in pilot-scale seawater cooling towers

    KAUST Repository

    Al-Bloushi, Mohammed; Saththasivam, Jayaprakash; Jeong, Sanghyun; Amy, Gary L.; Leiknes, TorOve

    2017-01-01

    Due to the scarcity of potable water in many regions of the world, the demand for seawater as an alternative evaporative cooling medium in cooling towers (CTs) has increased significantly in recent years. Seawater make-up in CTs is deemed the most feasible because of its unlimited supply in the coastal areas of Gulf and Red Sea. However, the seawater CTs have higher challenges greatly mitigating their performances because it is an open system where biofouling and bio-corrosion occurring within the fillers and piping of recirculation systems. Their pilot-scale CTs were constructed to assess the performance of three types of oxidizing biocides or oxidants, namely chlorine, chlorine dioxide (ClO2) and ozone, for biofouling control. The test results showed that the addition of organic (5mg/L of methanol (MeOH)) increased the bacterial growth in CT basin. All oxidants were effective in keeping the microbial growth to the minimum. Oxidation increased the oxidation-reduction potential (ORP) level from 270 to 600mV. Total residual oxidant (TRO) was increased with oxidation but it was slightly increased with organic addition. Other parameters including pH, dissolved oxygen (DO), conductivity levels were not changed. However, higher formation of disinfection by-products (DBPs) was detected with chlorination and ozonation. This indicates the organic level should be limited in the oxidation for biofouling control in seawater CTs.

  6. Acoustically excited encapsulated microbubbles and mitigation of biofouling

    KAUST Repository

    Qamar, Adnan

    2017-08-31

    Provided herein is a universally applicable biofouling mitigation technology using acoustically excited encapsulated microbubbles that disrupt biofilm or biofilm formation. For example, a method of reducing biofilm formation or removing biofilm in a membrane filtration system is provided in which a feed solution comprising encapsulated microbubbles is provided to the membrane under conditions that allow the encapsulated microbubbles to embed in a biofilm. Sonication of the embedded, encapsulated microbubbles disrupts the biofilm. Thus, provided herein is a membrane filtration system for performing the methods and encapsulated microbubbles specifically selected for binding to extracellular polymeric substances (EFS) in a biofilm.

  7. Stopping AI-2 chatter by means of an indigenous bacterium ( Acinetobacter sp. DKY-1): A new anti-biofouling strategy in an MBR for wastewater treatment.

    Science.gov (United States)

    Lee, Kibaek; Kim, Yea-Won; Lee, Seonki; Lee, Sang Hyun; Nahm, Chang Hyun; Kwon, Hyeokpil; Park, Pyung-Kyu; Choo, Kwang-Ho; Koyuncu, Ismail; Drews, Anja; Lee, Chung-Hak; Lee, Jung-Kee

    2018-05-01

    Bacterial quorum quenching (QQ) by means of degrading signaling molecules has been applied to anti-biofouling strategy in a membrane bioreactor (MBR) for wastewater treatment. However, the target signaling molecules have been limited to N-acyl homoserine lactones participating in intra-species quorum sensing. Here, an approach to disrupt autoinducer-2 (AI-2) signaling molecules participating in inter-species quorum sensing, was pursued as a next-generation anti-biofouling strategy in an MBR for wastewater treatment. We isolated an indigenous QQ bacterium ( Acinetobacter sp. DKY-1) that can attenuate the expression of quorum sensing (QS) response through inactivation of autoinducer-2 signaling molecule, 4,5-dihydroxy-2,3-pentanedione (DPD) among four kinds of autoinducer-2 QS bacteria. DKY-1 released AI-2 QQ compound(s), which was verified to be hydrophilic with a molecular weight biofouling. This new approach, combining molecular biology with wastewater engineering, could enlarge the range of QQ-MBR for anti-biofouling and energy savings in the field of wastewater treatment.

  8. Membrane biofouling characterization: effects of sample preparation procedures on biofilm structure and the microbial community

    KAUST Repository

    Xue, Zheng; Lu, Huijie; Liu, Wen-Tso

    2014-01-01

    Ensuring the quality and reproducibility of results from biofilm structure and microbial community analysis is essential to membrane biofouling studies. This study evaluated the impacts of three sample preparation factors (ie number of buffer rinses

  9. Modelling of the impact of biofouling on hydrodynamics downstream of a tidal turbine

    Science.gov (United States)

    Bennis, A. C.; Rivier, A.; Dauvin, J. C.

    2016-02-01

    Biological organisms, like barnacles, mussels or bryozoans, colonize rapidly an immersed surface and could form a thickness until several centimeters on it. This biofouling could modify hydrodynamics around tidal turbine by increasing drag and hence resistance and could be detrimental to the performance of turbine (e.g. Orme et al., 2001; Khor and Xiao, 2011). Our work focuses on modifications of vortices downstream of a tidal turbine due to biofouling using CFD. Fixed biological organisms are solved explicitly by the model and are considered by modifying the blade profile. Firstly an airfoil colonized by barnacles is modelled for various fouling height and spacing and results are compared to experimental and simulated data (Orme et al., 2001; Khor and Xiao, 2011) in order to assess the capacity of the model to reproduce the flow around a blade with biofouling. Then a Darrieus vertical axis tidal turbine is modelled using a dynamic mesh. Configuration with smooth clean blades is assessed by comparison with experiments and simulations made by Roa (2011) and Bossard (2012). Biological organisms with various heights, spacing and shapes are fixed on blades and wakes downstream of clean and colonized tidal turbine are compared. Vorticity fields around the tidal turbine are clearly modified when blades are colonized. Samples will be taken from location where farms are planned to be built (Alderney Race/Raz Blanchard) to characterize more precisely the characteristics of species which are liable to fix on tidal turbine.Reference:Bossard (2012). Doctoral dissertation, Université de Grenoble.Khor & Xiao. (2011). Ocean Eng, 38(10), 1065-1079. Orme et al. (2001). Marine Renewable Energy Conference, Newcastle.Roa (2011).Doctoral dissertation, Université de Grenoble.

  10. Marine Biofouling of Surfaces: Morphology, and Nanomechanics of Barnacle Cyprid Adhesion Proteins by AFM

    NARCIS (Netherlands)

    Phang, In Yee

    2008-01-01

    The understanding of biointerfaces in contact with seawater is crucially important in tackling the problems of marine biofouling. Such biointerfaces involve the bioadhesives used by marine organisms to attach temporary or permanently to the surfaces immersed in water. The aim of this Thesis is to

  11. Compositional Similarities and Differences between Transparent Exopolymer Particles (TEP) from two Marine Bacteria and two Marine Algae: Significance to Surface Biofouling

    KAUST Repository

    Li, Sheng

    2015-06-12

    Transparent-exopolymer-particles (TEP) have been recently identified as a significant contributor to surface biofouling, such as on reverse osmosis (RO) membranes. TEP research has mainly focused on algal TEP/TEP precursors while limited investigations have been conducted on those released by bacteria. In this study, TEP/TEP precursors derived from both algae and bacteria were isolated and then characterized to investigate their similarities and/or differences using various advanced analytical techniques, thus providing a better understanding of their potential effect on biofouling. Bacterial TEP/TEP precursors were isolated from two species of marine bacteria (Pseudidiomarina homiensis and Pseudoalteromonas atlantica) while algal TEP/TEP precursors were isolated from two marine algae species (Alexandrium tamarense and Chaetoceros affinis). Results indicated that both isolated bacterial and algal TEP/TEP precursors were associated with protein-like materials, and most TEP precursors were high-molecular-weight biopolymers. Furthermore all investigated algal and bacterial TEP/TEP precursors showed a lectin-like property, which can enable them to act as a chemical conditioning layer and to agglutinate bacteria. This property may enhance surface biofouling. However, both proton nuclear magnetic resonance (NMR) spectra and the nitrogen/carbon (N/C) ratios suggested that the algal TEP/TEP precursors contained much less protein content than the bacterial TEP/TEP precursors. This difference may influence their initial deposition and further development of surface biofouling.

  12. Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water.

    Science.gov (United States)

    Chien, S H; Hsieh, M K; Li, H; Monnell, J; Dzombak, D; Vidic, R

    2012-02-01

    Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ∕h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m∕s), and air mass velocity (3660 kg∕h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

  13. Biofouling community pattern on various metallic surfaces in the coastal waters of Kalpakkam, Southwestern Bay of Bengal

    International Nuclear Information System (INIS)

    Sahu, Gouri; Satpathy, K.K.; Mohanty, A.K.; Bindu, V.K.

    2015-01-01

    Biofouling causes great operational hazard in different marine installations across the globe. And the expenditure incurred on combating biofouling is astounding. It is reported that shut down of a 235 MW (e) power station due to fouling, costs about 170 lakhs (at Rs. 3.00 per kw/h) per day. Because of this economic implication, biofouling has been a thrust area of study for the marine researchers. To assess the biofouling pattern, metallic surfaces are the best options because of their extensive use at various installations in the marine environment. Hence, knowledge on qualitative and quantitative aspects of biofouling with respect to metal surfaces is of great value to design an efficient fouling control strategy. Keeping this in mind, nine types of metal (SS-316, SS-304, MS, Titanium, Admiralty Brass, Aluminum Brass, Copper, Monel and Cupro-nickel) panels (12 x 9 x 0.1 cm) were exposed to coastal water of Kalpakkam from MAPS jetty at a depth of 2 m below the lowest low tide. Results indicated that copper based panels were found to be foul-free except monel. Although, fouling settlement was encountered on monel, the adherence was weak. Non-copper based metals showed 100% area coverage with high population density. However, in case of MS, due to exfoliation of corrosion deposits, unevenness in fouling colonization at later stages of development took place, though the early settlement was unaffected by initial corrosion. As expected, Titanium showed high rate of fouling growth along with high fouling diversity compared to other non-copper based metals. Absence of specific foulants such as, crustaceans and algae on Titanium surface reported by others was not observed during our study. The information on Titanium would be handy for Prototype Fast Breeder Reactor (PFBR) cooling water system wherein, the same has been selected as condenser and process water heat exchanger material. For non-copper based alloys including monel the fouling load ranged from 18 to 40 g

  14. Chlorine dioxide as biocide to prevent biofouling in the hydro technical structures at KKNPP

    International Nuclear Information System (INIS)

    Ganesh, S.; Selvaraj, S.; Balasubramanian, M.R.; Selvavinayagam, P.; Sundar, R.S.

    2008-01-01

    Chlorination is envisaged in the sea water systems of KKNPP to control macro and micro bio-fouling of underwater structures and equipments. KKNPP intake and the fore bay structures are shown in detail. The sodium hypo chlorite required for chlorination is produced in the electro chlorination plant at site by the electrolysis of sea water. It is added in the sea water at the intake structure, tunnels and fore bay on continuous as well as periodic basis. The sea water to chlorination plant is supplied by the pumps located at the main pump house. Chlorination of sea water system by electro-chlorination is possible only after pump house flooding and commissioning of electro-chlorination plant. So for the period from breach of temporary dyke till commissioning of electro chlorination plant, chlorination by temporary method has to be done to prevent the bio-fouling of underwater structures and equipments. The flooding of the pump house subsequent to breach of temporary dyke is done

  15. Development of a setup to enable stable and accurate flow conditions for membrane biofouling studies

    KAUST Repository

    Bucs, Szilard; Farhat, Nadia; Siddiqui, Amber; Valladares Linares, Rodrigo; Radu, Andrea; Kruithof, Joop C.; Vrouwenvelder, Johannes S.

    2015-01-01

    on membrane performance parameters such as feed channel pressure drop. There is a suite of available monitors to study biofouling, but systems to operate monitors have not been well designed to achieve an accurate, constant water flow required for a reliable

  16. Biofouling on Coated Carbon Steel in Cooling Water Cycles Using Brackish Seawater

    Directory of Open Access Journals (Sweden)

    Pauliina Rajala

    2016-11-01

    Full Text Available Water cooling utilizing natural waters is typically used for cooling large industrial facilities such as power plants. The cooling water cycles are susceptible to biofouling and scaling, which may reduce heat transfer capacity and enhance corrosion. The performance of two fouling-release coatings combined with hypochlorite treatment were studied in a power plant utilizing brackish sea water from the Baltic Sea for cooling. The effect of hypochlorite as an antifouling biocide on material performance and species composition of microfouling formed on coated surfaces was studied during the summer and autumn. Microfouling on surfaces of the studied fouling-release coatings was intensive in the cooling water cycle during the warm summer months. As in most cases in a natural water environment the fouling consisted of both inorganic fouling and biofouling. Chlorination decreased the bacterial number on the surfaces by 10–1000 fold, but the efficacy depended on the coating. In addition to decreasing the bacterial number, the chlorination also changed the microbial species composition, forming the biofilm on the surfaces of two fouling-release coatings. TeknoTar coating was proven to be more efficient in combination with the hypochlorite treatment against microfouling under these experimental conditions.

  17. Effects and recovery of biofouling communities impacted by a controlled Orimulsion spill

    International Nuclear Information System (INIS)

    Schiazza, J. La; Rodriguez-Grau, J.; Losada, F.

    1995-01-01

    Biofouling communities are a naturally occurring array of marine sessile organisms having brief periods of larval stages during their early development. Herein, this paper evaluates the usefulness of these organisms as in situ bioindicators of environmental stress caused by a controlled Orimulsion spill, monitoring changes of some ecological variables as response indicators. To this end, artificial substrates (plates) were placed at a coastal sector of Venezuela. After recruitment and development of the organisms during 105 days, the plates were impacted with Orimulsion in tanks during 95 minutes and returned to their original recruiting site, where they remained for 60 days. Biological response and recovery assessment were followed at 7, 28 and 60 days after exposure. Other biological indicators of stress showed no differences between both experimental groups. An important observation was a faster recolonization of some species during the recovery process, attributed to an increased spatial heterogeneity provided by the already existing sessile organisms. The overall conclusion is that biofouling has a high recovery capacity and despite an actual acute disturbance, these community indicators returned to a biological equilibrium within less than 60 days of the post exposure period

  18. Application of monochloramine for wastewater reuse: Effect on biostability during transport and biofouling in RO membranes

    KAUST Repository

    Siddiqui, Amber; Loubineaud, E.; Prest, E.I.E.C.; El Chakhtoura, Joline; Salles, C.; Bucs, Szilard; Trampé , J.; Van den Broek, W.B.P.; Van Agtmaal, J.M.C.; Van Loosdrecht, M.C.M.; Kruithof, J.C.; Vrouwenvelder, Johannes S.

    2018-01-01

    The rising demand for clean and safe water has increased the interest in advanced wastewater treatment and reuse. Reverse osmosis (RO) can provide reliable and high-quality water from treated wastewater. Biofouling inevitably occurs, certainly

  19. Biocorrosion and biofouling of metals and alloys of industrial usage. Present state of the art at the beginning of the new millennium

    OpenAIRE

    Videla, H. A.

    2003-01-01

    An overview on the present state of the art on Biocorrosion and Biofouling of metals and alloys of industrial usage is offered on the basis of the experience gathered in our laboratory over 25 years of research. The key concepts to understand the main effects of microorganisms on metal decay are briefly discussed. New trends in monitoring and control strategies to mitigate biocorrosion and biofouling deleterious effects are also described. Several relevant cases of biocorrosion studied by our...

  20. Online monitoring of biofouling using coaxial stub resonator technique

    Directory of Open Access Journals (Sweden)

    N.A. Hoog

    2015-03-01

    Analysis of the biofilm and the stub resonator signal, both as function of time, indicates that the sensor allows detection of early stages of biofilm formation. In addition, the sensor signal clearly discriminates between the first stages of biofilm formation (characterized by separated, individual spots of bacterial growth on the glass beads and the presence of a nearly homogeneous biofilm later on in time. Model simulations based on the transmission line theory predict a shift of the sensor response in the same direction and order of magnitude as observed in the biofouling experiments, thereby confirming the operating principle of the sensor.

  1. Super Duplex Stainless Steel Surfaces and their Effects on Marine Biofouling

    OpenAIRE

    Falk, Adrian

    2017-01-01

    Some of the world’s most ancient, but still viable, organisms have since the beginning of maritime caused problems for the industry. The problems affect both the longlivety and efficiency of ships which is caused by the mere presence of organisms attached to the ship hulls. The organisms, called biofoulers, causes problems with longlivety related to moisture and crevice corrosion which break down the hull material. The problem regarding efficiency of the ship is related to the added hydrodyna...

  2. Comparisons of Flow Patterns over a Hierarchical and a Non-hierarchical Surface in Relation to Biofouling Control

    Directory of Open Access Journals (Sweden)

    Bin Ahmad Fawzan Mohammed Ridha

    2018-01-01

    Full Text Available Biofouling can be defined as unwanted deposition and development of organisms on submerged surfaces. It is a major problem as it causes water contamination, infrastructures damage and increase in maintenance and operational cost especially in the shipping industry. There are a few methods that can prevent this problem. One of the most effective methods which is using chemicals particularly Tributyltin has been banned due to adverse effects on the environment. One of the non-toxic methods found to be effective is surface modification which involves altering the surface topography so that it becomes a low-fouling or a non-stick surface to biofouling organisms. Current literature suggested that non-hierarchical topographies has lower antifouling performance compared to hierarchical topographies. It is still unclear if the effects of the flow on these topographies could have aided in their antifouling properties. This research will use Computational Fluid Dynamics (CFD simulations to study the flow on these two topographies which also involves comparison study of the topographies used. According to the results obtained, it is shown that hierarchical topography has higher antifouling performance compared to non-hierarchical topography. This is because the fluid characteristics at the hierarchical topography is more favorable in controlling biofouling. In addition, hierarchical topography has higher wall shear stress distribution compared to non-hierarchical topography

  3. Improving the reliability of open-cycle water systems: Application of biofouling surveillance and control techniques to sediment and corrosion fouling at nuclear power plants

    International Nuclear Information System (INIS)

    Johnson, K.I.; Neitzel, D.A.

    1987-03-01

    Biofouling surveillance and control techniques are evaluated for their applicability to sediment and corrosion fouling and suggestions are given to improve their effectiveness. Alternate techniques to better detect and control sedimentation and corrosion are also evaluated. Environmental conditions that allow biofouling, sedimentation, and corrosion to occur are summarized. A correlation between sediment and corrosion is identified and the causes are described. Environmental regulations, especially those in the Clean Water Act of 1977, are reviewed to identify those that may limit or prevent the use of surveillance and control techniques described in this report. Flow velocity is the major design factor that determines whether or not biofouling, sedimentation, and corrosion will occur. Monitoring flow conditions can provide early warning of conditions that will allow fouling to occur. Visual inspection is the most common and most effective technique for identifying the cause and extent of fouling in the open-cycle water system. Most biofouling control techniques in current use are not effective against sediment and corrosion. Frequent, high-velocity flushing of cooling loops may effectively remove sediment and reduce under-sediment corrosion. Alternate biocide treatments such as targeted chlorination or the use of ozone or 2,2-dibromo-3-nitrilo propionamide (DBNPA) may also be effective in reducing under-sediment corrosion

  4. Nanocomposite strategies for limiting medical and marine biofouling

    Science.gov (United States)

    Cooper, Scott Patrick

    Microorganisms affect many aspects of human life. When microorganisms colonize a surface, the resulting microbial community is called a biofilm. Biofilms can negatively affect human health and productivity. Osteomyelitis is caused by biofilms of bacteria attached to the bone. These biofilms pose a threat to human life and lead to the loss of healthy tissue. Biofilms attached to marine vessels decrease the fuel economy of ships, resulting in a significant economic cost. There is a need to develop new materials which eradicate and prevent biofouling. Nanocomposites and mixed-phase organic/inorganic materials are presented in various embodiments as a means to limit biofouling. Antibiotic-filled microspheres are created to improve the treatment of osteomyelitis. These microspheres consist of bioactive glass and poly(n-vinylpyrrolidone) (PVP) or gelatin. Bioactive glasses have historically been shown to promote the regeneration of bone. Sol-gel chemistry is used to make the bioactive glass component, in this case a calcium silicate. The low temperature of the reaction allows organic molecules such as drugs and polymers to be blended with the glass. The catalyst used during the sol-gel reaction affects the structure and composition of the microspheres. Base catalysis leads to microspheres that exhibit behavior indicative of a nanocomposite structure. Acid catalysis produces microspheres that appear to exist as more as a mixed phase between silica and PVP. These structures directly affect the stability of the microspheres in simulated body fluid (SBF): base-catalyzed microspheres degrade within the first day in SBF, while acid-catalyzed microspheres are stable for at least one week. The morphology of acid-catalyzed microspheres is directly affected by the following compositional parameters: molecular weight of PVP, concentration of PVP, and concentration of calcium. Solid, hollow, and core/shell morphologies are produced by adjusting these parameters. These morphologies

  5. Membrane biofouling in a wastewater nitrification reactor: microbial succession from autotrophic colonization to heterotrophic domination

    KAUST Repository

    Lu, Huijie

    2015-10-22

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles.

  6. Development of anti-biofouling methods for gate facilities

    International Nuclear Information System (INIS)

    Fukuoka, Mari; Akamine, Kenichi; Iai, Yuuichi; Takatoo, Norihiro; Fukushima, Noriaki

    2016-01-01

    In the maintenance and management of gate facilities, a large sum of money and labor are required to remove and clean organisms that attach themselves to the facilities. That is why we developed two anti-biofouling systems, one that uses a weak electric current and another that uses ultrasonic waves. We carried out basic examinations and actual environment examinations to verify the effects of these methods. As a result, it has been confirmed that these methods effectively anti-foul the parts they are applied to, and that they can be used on gate facilities. In the future, we will evaluate their adaptability to aqueducts, such as those used in thermal and nuclear power plants, and marine structures, such as floating breakwaters, in addition to gate facilities. (author)

  7. On the Modelling of Algal Biofouling Growth on Nano-TiO2 Coated and Uncoated Limestones and Sandstones

    Directory of Open Access Journals (Sweden)

    Lorenzo Graziani

    2018-02-01

    Full Text Available Algal biofouling on archaeological and historic materials, as well as in modern building façade, is a common phenomenon that occurs when microorganisms of various nature adhere to the material, forming biological stains and patinas. It can significantly deteriorate the aesthetic and even mechanical quality of historic and archaeological artifacts. Thus, predicting the colonization progress of algae on treated and untreated materials can be helpful to establish appropriate schedules and methods of maintenance. In this way, the aim of this research was to modelize the algal colonization on nano-TiO2 coated and uncoated stone surfaces, usually found in historic and archaeological artifacts, by following Avrami’s theory. Particular attention was paid on correlating the model with some properties of the substrate, like roughness and porosity. Biofouling was tested on two sandstones and three limestone with different intrinsic characteristics (porosity, roughness by means of an accelerated lab-scale test. A suspension of green alga Chlorella mirabilis and cyanobacteria Chroococcidiopsis fissurarum was used as biofouling. Digital image analysis was carried out in order to find the attachment rate and the growth of algal spots. Results show that the attachment specific rate increased linearly with time, and the assumption of a constant growth rate was acceptable. A good agreement between the simulation and the experimental results was obtained with a maximum error of 0.59%.

  8. Development of a functionalized coating for inhibition of marine corrosion and biofouling

    Science.gov (United States)

    Gittens, Jeanette Elizabeth

    The financial loss incurred by corrosion of metals in the marine environment has led to a need to develop effective, economic and environmentally friendly methods of protection. Traditional methods of counteracting the development of surface biofilms and biofouling within aqueous environments have involved implementing chemical biocides, often with a deleterious effect on non-target organisms. Sol gel coating technology offers a convenient route for immobilizing functional additives, such as inhibitors or, in the case of this study, biologically active microorganisms. Paenibacillus polymyxa biofilms inhibit the corrosion of metal substrates and this strain has the advantage of forming endospores can withstand the solvent and acid concentrations required in sol-gel formulation. Encapsulation of viable P. polymyxa endospores within the sol-gel matrix allowed germination on exposure to nutrients, when germinating endospores and vegetative cells were seen after fluorescence microscopy to be distributed throughout the coating. Laboratory electrochemical impedance tests were used to characterize the corrosion behaviour of the endospore-containing (biotic) sol-gel coating in comparison to an abiotic (no endospores) sol-gel only coating and one containing non-viable (killed) endospores. The technology enabled manipulation of the sol-gel formulation and the method of application to produce biotic sol-gel with enhanced corrosion inhibition properties on aluminium alloy. Field trials in a marine environment confirmed the corrosion protecting properties of the biotic coating and that the biotic coatings inhibited macroscopic biofouling for at least 29 weeks relative to the controls without encapsulated live endospores. Production of polymyxin by the encapsulated bacteria, which was proposed as a mechanism by which they inhibit MIC, was less than 1 mug per ml and below the threshold of detection by liquid chromatography mass spectrometry and antimicrobial bioassay. Microcosm

  9. In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

    KAUST Repository

    Fortunato, Luca; Leiknes, TorOve

    2017-01-01

    Membrane systems for water purification can be seriously hampered by biofouling. The use of optical coherence tomography (OCT) to investigate biofilms in membrane systems has recently increased due to the ability to do the characterization in

  10. Compositional Similarities and Differences between Transparent Exopolymer Particles (TEP) from two Marine Bacteria and two Marine Algae: Significance to Surface Biofouling

    KAUST Repository

    Li, Sheng; Winters, Harvey; Villacorte, L.O.; Ekowati, Y.; Emwas, Abdul-Hamid M.; Kennedy, M.D.; Amy, Gary L.

    2015-01-01

    indicated that both isolated bacterial and algal TEP/TEP precursors were associated with protein-like materials, and most TEP precursors were high-molecular-weight biopolymers. Furthermore all investigated algal and bacterial TEP/TEP precursors showed a lectin-like property, which can enable them to act as a chemical conditioning layer and to agglutinate bacteria. This property may enhance surface biofouling. However, both proton nuclear magnetic resonance (NMR) spectra and the nitrogen/carbon (N/C) ratios suggested that the algal TEP/TEP precursors contained much less protein content than the bacterial TEP/TEP precursors. This difference may influence their initial deposition and further development of surface biofouling.

  11. Membrane biofouling in a wastewater nitrification reactor: Microbial succession from autotrophic colonization to heterotrophic domination.

    Science.gov (United States)

    Lu, Huijie; Xue, Zheng; Saikaly, Pascal; Nunes, Suzana P; Bluver, Ted R; Liu, Wen-Tso

    2016-01-01

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles. Copyright © 2015 Elsevier Ltd. All

  12. Ups and downs in the ocean. Modelling the effect of biofouling on the vertical transport of microplastics

    NARCIS (Netherlands)

    Kooi, M.; Nes, van E.H.; Scheffer, M.; Koelmans, A.A.

    2017-01-01

    Recent studies suggest size-selective removal of small plastic particles from the ocean surface, an observation that remains unexplained. We studied one of the hypotheses regarding this size-selective removal: the formation of a biofilm on the microplastics (biofouling). We developed the first

  13. Ups and Downs in the Ocean: Effects of Biofouling on Vertical Transport of Microplastics.

    Science.gov (United States)

    Kooi, Merel; Nes, Egbert H van; Scheffer, Marten; Koelmans, Albert A

    2017-07-18

    Recent studies suggest size-selective removal of small plastic particles from the ocean surface, an observation that remains unexplained. We studied one of the hypotheses regarding this size-selective removal: the formation of a biofilm on the microplastics (biofouling). We developed the first theoretical model that is capable of simulating the effect of biofouling on the fate of microplastic. The model is based on settling, biofilm growth, and ocean depth profiles for light, water density, temperature, salinity, and viscosity. Using realistic parameters, the model simulates the vertical transport of small microplastic particles over time, and predicts that the particles either float, sink to the ocean floor, or oscillate vertically, depending on the size and density of the particle. The predicted size-dependent vertical movement of microplastic particles results in a maximum concentration at intermediate depths. Consequently, relatively low abundances of small particles are predicted at the ocean surface, while at the same time these small particles may never reach the ocean floor. Our results hint at the fate of "lost" plastic in the ocean, and provide a start for predicting risks of exposure to microplastics for potentially vulnerable species living at these depths.

  14. Comparing Biofouling Control Treatments for Use on Aquaculture Nets

    Directory of Open Access Journals (Sweden)

    Geoffrey Swain

    2014-12-01

    Full Text Available Test panels comprised of uncoated, copper coated and silicone coated 7/8'' (22 mm mesh knitted nylon net were evaluated to compare their properties and the effectiveness to prevent biofouling. This paper describes test procedures that were developed to quantify the performance in terms of antifouling, cleanability, drag and cost. The copper treatment was the most effective at controlling fouling, however, the silicone treated nets were the easiest to clean. The drag forces on the net were a function of twine diameter, twine roughness and fouling. After immersion, the uncoated nets had the most drag followed by the silicone and copper treatments. The cost of applying silicone to nets is high; however, improved formulations may provide a non-toxic alternative to control fouling.

  15. Corrosion and biofouling resistance evaluation of 90-10 copper-nickel

    Energy Technology Data Exchange (ETDEWEB)

    Powell, Carol [Consultant to Copper Development Association, UK, Square Covert, Caynham, Ludlow, Shropshire (United Kingdom)

    2004-07-01

    Copper-nickel alloys for marine use were developed for naval applications in the early part of the 20. century with a view to improving the corrosion resistance of condenser tubes and seawater piping. They still enjoy widespread use today not only for many navies but also in commercial shipping, floating production, storage and off loading vessels (FPSOs), and in multistage flash desalination. The two popular alloys contain 90% or 70% copper and differ in strength and maximum sea water velocity levels they can handle but it is the 90-10 copper-nickel (CuNi10Fe1Mn) which is the more economic and extensively used. An additional benefit of this alloy is its high resistance to biofouling: in recent years this has led to sheathing developments particularly for structures and boat hulls. This paper provides a review of the corrosion and biofouling resistance of 90-10 copper-nickel based on laboratory test data and documented experience of the alloy in marine environments. Particular attention is given to exposure trials over 8 years in Langstone Harbour, UK, which have recently been completed by Portsmouth University on behalf of the Nickel Institute. These examined four sheathing products; plate and foil as well as two composite products with rubber backing. The latter involved copper-nickel granules and slit sheet. The trial results are consistent with the behaviour of the alloy in the overall review. There is an inherent high resistance to marine biofouling when freely exposed. Prolonged exposure to quiet conditions can result in some growth of marine organisms but this is loosely attached and can readily be removed by wiping or a light scraping. The good corrosion resistance of 90-10 copper-nickel in sea water is also confirmed and associated with the formation of a thin, complex, protective and predominantly cuprous oxide surface film, which forms and matures naturally on exposure to seawater. Sound initial oxide film formation is also known to help protect against

  16. Prevention and protection of the effects of biocorrosion and biofouling minimizing the environmental impact

    OpenAIRE

    Gómez de Saravia, S. G.; Guiamet, P. S.; Videla, H. A.

    2003-01-01

    Biocorrosion and biofouling processes are mediated by microorganisms adhered to the metal surfaces or embedded in a gelatinous matrix called biofilm. Biofilms affect the interaction between metals and the environment not only in deleterious processes like corrosion but also in several biological processes applied to materials recovery and handling. The growth of the microorganisms capable to induce biocorrosion is conditioned by favorable environmental conditions. However, the chemical agents...

  17. Effects of poly-ether B on proteome and phosphoproteome expression in biofouling Balanus amphitrite cyprids

    KAUST Repository

    Dash, Swagatika

    2012-04-01

    Biofouling is ubiquitous in marine environments, and the barnacle Balanus amphitrite is one of the most recalcitrant and aggressive biofoulers in tropical waters. Several natural antifoulants that were claimed to be non-toxic have been isolated in recent years, although the mechanism by which they inhibit fouling is yet to be investigated. Poly-ether B has shown promise in the non-toxic inhibition of larval barnacle attachment. Hence, in this study, multiplex two-dimensional electrophoresis (2-DE) was applied in conjunction with mass spectrometry to investigate the effects of poly-ether B on barnacle larvae at the molecular level. The cyprid proteome response to poly-ether B treatment was analyzed at the total proteome and phosphoproteome levels, with 65 protein and 19 phosphoprotein spots found to be up- or down-regulated. The proteins were found to be related to energy-metabolism, oxidative stress, and molecular chaperones, thus indicating that poly-ether B may interfere with the redox-regulatory mechanisms governing the settlement of barnacle larvae. The results of this study demonstrate the usefulness of the proteomic technique in revealing the working mechanisms of antifouling compounds. © 2012 Copyright Taylor and Francis Group, LLC.

  18. Assessing the use of Low Voltage UV-light Emitting Miniature LEDs for Marine Biofouling Control

    Science.gov (United States)

    2016-07-01

    of that required to drive traditional UV mercury lamps . Secondly, given their small size and relatively low cost, UV LEDs provide ease of maintenance...UNCLASSIFIED UNCLASSIFIED Assessing the use of Low Voltage UV -light Emitting Miniature LEDs for Marine Biofouling Control Richard...settling organisms. The introduction of miniature UV light emitting diodes ( LEDs ) as a light source enables them to be embedded into thin, flexible

  19. Microsphere erosion in outer hydrogel membranes creating macroscopic porosity to counter biofouling-induced sensor degradation.

    Science.gov (United States)

    Vaddiraju, S; Wang, Y; Qiang, L; Burgess, D J; Papadimitrakopoulos, F

    2012-10-16

    Biofouling and tissue inflammation present major challenges toward the realization of long-term implantable glucose sensors. Following sensor implantation, proteins and cells adsorb on sensor surfaces to not only inhibit glucose flux but also signal a cascade of inflammatory events that eventually lead to permeability-reducing fibrotic encapsulation. The use of drug-eluting hydrogels as outer sensor coatings has shown considerable promise to mitigate these problems via the localized delivery of tissue response modifiers to suppress inflammation and fibrosis, along with reducing protein and cell absorption. Biodegradable poly (lactic-co-glycolic) acid (PLGA) microspheres, encapsulated within a poly (vinyl alcohol) (PVA) hydrogel matrix, present a model coating where the localized delivery of the potent anti-inflammatory drug dexamethasone has been shown to suppress inflammation over a period of 1-3 months. Here, it is shown that the degradation of the PLGA microspheres provides an auxiliary venue to offset the negative effects of protein adsorption. This was realized by: (1) the creation of fresh porosity within the PVA hydrogel following microsphere degradation (which is sustained until the complete microsphere degradation) and (2) rigidification of the PVA hydrogel to prevent its complete collapse onto the newly created void space. Incubation of the coated sensors in phosphate buffered saline (PBS) led to a monotonic increase in glucose permeability (50%), with a corresponding enhancement in sensor sensitivity over a 1 month period. Incubation in serum resulted in biofouling and consequent clogging of the hydrogel microporosity. This, however, was partially offset by the generated macroscopic porosity following microsphere degradation. As a result of this, a 2-fold recovery in sensor sensitivity for devices with microsphere/hydrogel composite coatings was observed as opposed to similar devices with blank hydrogel coatings. These findings suggest that the use of

  20. Biocorrosion and biofouling of metals and alloys of industrial usage. present state of the art at the beginning of the new millennium

    International Nuclear Information System (INIS)

    Videla, H. A.

    2003-01-01

    An overview on the present state of the art on Biocorrosion and Biofouling of metals and alloys of industrial usage is offered on the basis of the experience gathered in our laboratory over 25 years of research. The key concepts to understand the main effects of microorganisms on metal decay are briefly discussed. new trends in monitoring and control strategies to mitigate biocorrosion and biofouling deleterious effects are also described. Several relevant cases of biocorrosion studied by our research group are successively described: i) biocorrosion of aluminum and its alloys by fungal contaminants of jet fuels; ii) Sulfate-reducing bacteria SRB induced corrosion of steel; iii) biocorrosion and biofouling interactions in the marine environment: iv) monitoring strategies for assessing biocorrosion in industrial water systems; v) microbial inhibition of corrosion; vi) use and limitations of electrochemical techniques for evaluating biocorrosion effects. The future perspective of the field is made considering the potential of innovative techniques in microscopy (environmental scanning electron microscopy, confocal scanning laser microscopy, atomic force microscopy), new spectroscopy techniques used for the study of corrosion products and biofilms (energy dispersion X-ray analysis, X-ray photoelectron spectroscopy, electron microprobe analysis) and electrochemistry (electrochemical impedance spectroscopy, electrochemical noise analysis. (Author) 53 refs

  1. Biocorrosion and biofouling of metals and alloys of industrial usage. present state of the art at the beginning of the new millennium

    Energy Technology Data Exchange (ETDEWEB)

    Videla, H. A.

    2003-07-01

    An overview on the present state of the art on Biocorrosion and Biofouling of metals and alloys of industrial usage is offered on the basis of the experience gathered in our laboratory over 25 years of research. The key concepts to understand the main effects of microorganisms on metal decay are briefly discussed. new trends in monitoring and control strategies to mitigate biocorrosion and biofouling deleterious effects are also described. Several relevant cases of biocorrosion studied by our research group are successively described: i) biocorrosion of aluminum and its alloys by fungal contaminants of jet fuels; ii) Sulfate-reducing bacteria SRB induced corrosion of steel; iii) biocorrosion and biofouling interactions in the marine environment: iv) monitoring strategies for assessing biocorrosion in industrial water systems; v) microbial inhibition of corrosion; vi) use and limitations of electrochemical techniques for evaluating biocorrosion effects. The future perspective of the field is made considering the potential of innovative techniques in microscopy (environmental scanning electron microscopy, confocal scanning laser microscopy, atomic force microscopy), new spectroscopy techniques used for the study of corrosion products and biofilms (energy dispersion X-ray analysis, X-ray photoelectron spectroscopy, electron microprobe analysis) and electrochemistry (electrochemical impedance spectroscopy, electrochemical noise analysis. (Author) 53 refs.

  2. Dynamic surface deformation of silicone elastomers for management of marine biofouling: laboratory and field studies using pneumatic actuation.

    Science.gov (United States)

    Shivapooja, Phanindhar; Wang, Qiming; Szott, Lizzy M; Orihuela, Beatriz; Rittschof, Daniel; Zhao, Xuanhe; López, Gabriel P

    2015-01-01

    Many strategies have been developed to improve the fouling release (FR) performance of silicone coatings. However, biofilms inevitably build on these surfaces over time. Previous studies have shown that intentional deformation of silicone elastomers can be employed to detach biofouling species. In this study, inspired by the methods used in soft-robotic systems, controlled deformation of silicone elastomers via pneumatic actuation was employed to detach adherent biofilms. Using programmed surface deformation, it was possible to release > 90% of biofilm from surfaces in both laboratory and field environments. A higher substratum strain was required to remove biofilms accumulated in the field environment as compared with laboratory-grown biofilms. Further, the study indicated that substratum modulus influences the strain needed to de-bond biofilms. Surface deformation-based approaches have potential for use in the management of biofouling in a number of technological areas, including in niche applications where pneumatic actuation of surface deformation is feasible.

  3. The application of nitric oxide to control biofouling of membrane bioreactors.

    Science.gov (United States)

    Luo, Jinxue; Zhang, Jinsong; Barnes, Robert J; Tan, Xiaohui; McDougald, Diane; Fane, Anthony G; Zhuang, Guoqiang; Kjelleberg, Staffan; Cohen, Yehuda; Rice, Scott A

    2015-05-01

    A novel strategy to control membrane bioreactor (MBR) biofouling using the nitric oxide (NO) donor compound PROLI NONOate was examined. When the biofilm was pre-established on membranes at transmembrane pressure (TMP) of 88-90 kPa, backwashing of the membrane module with 80 μM PROLI NONOate for 45 min once daily for 37 days reduced the fouling resistance (Rf ) by 56%. Similarly, a daily, 1 h exposure of the membrane to 80 μM PROLI NONOate from the commencement of MBR operation for 85 days resulted in reduction of the TMP and Rf by 32.3% and 28.2%. The microbial community in the control MBR was observed to change from days 71 to 85, which correlates with the rapid TMP increase. Interestingly, NO-treated biofilms at 85 days had a higher similarity with the control biofilms at 71 days relative to the control biofilms at 85 days, indicating that the NO treatment delayed the development of biofilm bacterial community. Despite this difference, sequence analysis indicated that NO treatment did not result in a significant shift in the dominant fouling species. Confocal microscopy revealed that the biomass of biopolymers and microorganisms in biofilms were all reduced on the PROLI NONOate-treated membranes, where there were reductions of 37.7% for proteins and 66.7% for microbial cells, which correlates with the reduction in TMP. These results suggest that NO treatment could be a promising strategy to control biofouling in MBRs. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  4. Anti-biofouling 3D porous systems: the blend effect of oxazoline-based oligomers on chitosan scaffolds.

    Science.gov (United States)

    Correia, Vanessa G; Coelho, Margarida; Barroso, Telma; Raje, Vivek P; Bonifácio, Vasco D B; Casimiro, Teresa; Pinho, Mariana G; Aguiar-Ricardo, Ana

    2013-01-01

    The production, characterization and anti-biofouling activity of 3D porous scaffolds combining different blends of chitosan and oxazoline-based antimicrobial oligomers is reported. The incorporation of ammonium quaternized oligo(2-oxazoline)s into the composition of the scaffold enhances the stability of the chitosan scaffold under physiological conditions as well as its ability to repel protein adsorption. The blended scaffolds showed mean pore sizes in the range of 18-32 μm, a good pore interconnectivity and high porosity, as well as a large surface area, ultimate key features for anti-biofouling applications. Bovine serum albumin (BSA) adhesion profiles showed that the composition of the scaffolds plays a critical role in the chitosan-oligooxazoline system. Oligobisoxazoline-enriched scaffolds (20% w/w, CB8020) decreased protein adsorption (BSA) by up to 70%. Moreover, 1 mg of CB8020 was able to kill 99.9% of Escherichia coli cells upon contact, demonstrating its potential as promising material for production of tailored non-fouling 3D structures to be used in the construction of novel devices with applications in the biomedical field and water treatment processes.

  5. Effect of biological and coagulation pre-treatments to control organic and biofouling potential components of ultrafiltration membrane in the treatment of lake water.

    Science.gov (United States)

    Pramanik, Biplob Kumar; Kajol, Annaduzzaman; Suja, Fatihah; Md Zain, Shahrom

    2017-03-01

    Biological aerated filter (BAF), sand filtration (SF), alum and Moringa oleifera coagulation were investigated as a pre-treatment for reducing the organic and biofouling potential component of an ultrafiltration (UF) membrane in the treatment of lake water. The carbohydrate content was mainly responsible for reversible fouling of the UF membrane compared to protein or dissolved organic carbon (DOC) content. All pre-treatment could effectively reduce these contents and led to improve the UF filterability. Both BAF and SF markedly led to improvement in flux than coagulation processes, and alum gave greater flux than M. oleifera. This was attributed to the effective removal and/or breakdown of high molecular weight (MW) organics by biofilters. BAF led to greater improvement in flux than SF, due to greater breakdown of high MW organics, and this was also confirmed by the attenuated total reflection-Fourier transform infrared spectroscopy analysis. Coagulation processes were ineffective in removing biofouling potential components, whereas both biofilters were very effective as shown by the reduction of low MW organics, biodegradable dissolved organic carbon and assimilable organic carbon contents. This study demonstrated the potential of biological pre-treatments for reducing organic and biofouling potential component and thus improving flux for the UF of lake water treatment.

  6. Biofouling inhibition in MBR by Rhodococcus sp. BH4 isolated from real MBR plant.

    Science.gov (United States)

    Oh, Hyun-Suk; Kim, Sang-Ryoung; Cheong, Won-Suk; Lee, Chung-Hak; Lee, Jung-Kee

    2013-12-01

    It has been reported that an indigenous quorum quenching bacterium, Rhodococcus sp. BH4, which was isolated from a real plant of membrane bioreactor (MBR) has promising potential to control biofouling in MBR. However, little is known about quorum quenching mechanisms by the strain BH4. In this study, various characteristics of strain BH4 were investigated to elucidate its behavior in more detail in the mixed liquor of MBR. The N-acyl homoserine lactone hydrolase (AHL-lactonase) gene of strain BH4 showed a high degree of identity to qsdA in Rhodococcus erythropolis W2. The LC-ESI-MS analysis of the degradation product by strain BH4 confirmed that it inactivated AHL activity by hydrolyzing the lactone bond of AHL. It degraded a wide range of N-acyl homoserine lactones (AHLs), but there was a large difference in the degradation rate of each AHL compared to other reported AHL-lactonase-producing strains belonging to Rhodococcus genus. Its quorum quenching activity was confirmed not only in the Luria-Bertani medium, but also in the synthetic wastewater. Furthermore, the amount of strain BH4 encapsulated in the vessel as well as the material of the vessel substantially affected the quorum quenching activity of strain BH4, which provides useful information, particularly for the biofouling control in a real MBR plant from an engineering point of view.

  7. Desiccation as a mitigation tool to manage biofouling risks: trials on temperate taxa to elucidate factors influencing mortality rates.

    Science.gov (United States)

    Hopkins, Grant A; Prince, Madeleine; Cahill, Patrick L; Fletcher, Lauren M; Atalah, Javier

    2016-01-01

    The desiccation tolerance of biofouling taxa (adults and early life-stages) was determined under both controlled and 'realistic' field conditions. Adults of the ascidian Ciona spp. died within 24 h. Mortality in the adult blue mussel Mytilus galloprovincialis occurred within 11 d under controlled conditions, compared with 7 d when held outside. The Pacific oyster Crassostrea gigas was the most desiccation-tolerant taxon tested (up to 34 d under controlled conditions). Biofouling orientated to direct sunlight showed faster mortality rates for all the taxa tested. Mortality in Mytilus juveniles took up to 24 h, compared with 8 h for Ciona, with greater survival at the higher temperature (18.5°C) and humidity (~95% RH) treatment combination. This study demonstrated that desiccation can be an effective mitigation method for a broad range of fouling taxa, especially their early life-stages. Further work is necessary to assess risks from other high-risk species such as algae and cyst forming species.

  8. Biocorrosion and biofouling of metals and alloys of industrial usage. Present state of the art at the beginning of the new millennium

    Directory of Open Access Journals (Sweden)

    Videla, H. A.

    2003-12-01

    Full Text Available An overview on the present state of the art on Biocorrosion and Biofouling of metals and alloys of industrial usage is offered on the basis of the experience gathered in our laboratory over 25 years of research. The key concepts to understand the main effects of microorganisms on metal decay are briefly discussed. New trends in monitoring and control strategies to mitigate biocorrosion and biofouling deleterious effects are also described. Several relevant cases of biocorrosion studied by our research group are successively described: i biocorrosion of aluminum and its alloys by fungal contaminants of jet fuels; ii Sulfate-reducing bacteria SRB induced corrosion of steel; iii biocorrosion and biofouling interactions in the marine environment; iv monitoring strategies for assessing biocorrosion in industrial water systems; v microbial inhibition of corrosion; vi use and limitations of electrochemical techniques for evaluating biocorrosion effects. The future perspective of the field is made considering the potential of innovative techniques in microscopy (environmental scanning electron microscopy, confocal scanning laser microscopy, atomic force microscopy, new spectroscopical techniques used for the study of corrosion products and biofilms (energy dispersion X-ray analysis, X-ray photoelectron spectroscopy, electron microprobe analysis and electrochemistry (electrochemical impedance spectroscopy, electrochemical noise analysis.

    Se ofrece una revisión del estado actual del conocimiento sobre Biocorrosión y Biofouling de metales y aleaciones de uso industrial basada en la experiencia desarrollada en nuestro laboratorio durante 25 años de investigación en el área. Se discuten brevemente los conceptos clave necesarios para entender los principales efectos de los microorganismos en el deterioro de los metales. También se presentan las nuevas tendencias seguidas para el monitoreo y las nuevas estrategias de control para mitigar

  9. Tracing biofouling to the structure of the microbial community and its metabolic products: a study of the three-stage MBR process.

    Science.gov (United States)

    Gao, Dawen; Fu, Yuan; Ren, Nanqi

    2013-11-01

    The biofouling characteristics of a sequential anoxic/aerobic-membrane bioreactor (A/O MBR) were analyzed during the three-stage process (fast-slow-fast transmembrane pressure (TMP) increasing). The results indicated: during the stage 1 (before day 1), the microbial communities in the activated sludge (AS), cake sludge (CS) and biofilm (BF) were similar to each other, and the adsorption of microbes and the metabolic products was the main factor that led to TMP increase; during the stage 2 (between day 1 and day 7), the cake layer begun to form and the TMP continued to rise gradually at a reduced rate compared to stage 1, at this point a characteristic microbial community colonized the CS with microorganisms such as Saprospiraceae and Comamonadaceae thriving on the membrane surface (BF) probably due to greater nutrient availability, and the predominance of these species in the microbial population led to the accumulation of biofouling metabolic products in the CS, which resulted in membrane fouling and the associated rise in TMP; during the final stage (after day 7), the biofilm had matured, and the activity of anaerobes stimulated cake compaction. The statistical analysis showed a correlation between the TMP changing rate and the carbonhydrates of soluble microbial products (SMPc) content in the CS. When the SMPc concentration rose slowly there was a low level of biofouling. However, when the SMPc accumulating rate was greater, it resulted in the more severe biofouling associated with the TMP jump. Furthermore, the correlation coefficient for the TMP increase and protein concentrations of extracellular polymeric substances (EPSp) in the CS was highly significant. The cluster analysis suggested that the AS microbial community remained stable during the three TMP change stages, while the CS and BF community were changed accompanied with the TMP change. The interaction between the microbial communities and the metabolic products lead to the significant correlation

  10. Environmentally Benign and Permanent Modifications to Prevent Biofouling on Marine and Hydrokinetic Devices

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Zhang

    2012-04-19

    Semprus Biosciences is developing environmentally benign and permanent modifications to prevent biofouling on Marine and Hydrokinetic (MHK) devices. Biofouling, including growth on external surfaces by bacteria, algae, barnacles, mussels, and other marine organisms, accumulate quickly on MHK devices, causing mechanical wear and changes in performance. Biofouling on crucial components of hydrokinetic devices, such as rotors, generators, and turbines, imposes substantial mass and hydrodynamic loading with associated efficiency loss and maintenance costs. Most antifouling coatings leach toxic ingredients, such as copper and tributyltin, through an eroding process, but increasingly stringent regulation of biocides has led to interest in the development of non-biocidal technologies to control fouling. Semprus Biosciences research team is developing modifications to prevent fouling from a broad spectrum of organisms on devices of all shapes, sizes, and materials for the life of the product. The research team designed and developed betaine-based polymers as novel underwater coatings to resist the attachment of marine organisms. Different betaine-based monomers and polymers were synthesized and incorporated within various coating formulations. The formulations and application methods were developed on aluminum panels with required adhesion strength and mechanical properties. The coating polymers were chemically stable under UV, hydrolytic and oxidative environments. The sulfobetaine formulations are applicable as nonleaching and stable underwater coatings. For the first time, coating formulations modified with highly packed sulfobetaine polymers were prepared and demonstrated resistance to a broad spectrum of marine organisms. Assays for comparing nonfouling performance were developed to evaluate protein adsorption and bacteria attachment. Barnacle settlement and removal were evaluated and a 60-day field test was performed. Silicone substrates including a commercial

  11. Biofouling-resilient nanoporous gold electrodes for DNA sensing.

    Science.gov (United States)

    Daggumati, Pallavi; Matharu, Zimple; Wang, Ling; Seker, Erkin

    2015-09-01

    Electrochemical nucleic acid sensors are promising tools for point-of-care diagnostic platforms with their facile integration with electronics and scalability. However, nucleic acid detection in complex biological fluids is challenging as biomolecules nonspecifically adsorb on the electrode surface and adversely affect the sensor performance by obscuring the transport of analytes and redox species to the electrode. We report that nanoporous gold (np-Au) electrodes, prepared by a microfabrication-compatible self-assembly process and functionalized with DNA probes, enabled detection of target DNA molecules (10-200 nM) in physiologically relevant complex media (bovine serum albumin and fetal bovine serum). In contrast, the sensor performance was compromised for planar gold electrodes in the same conditions. Hybridization efficiency decreased by 10% for np-Au with coarser pores revealing a pore-size dependence of sensor performance in biofouling conditions. This nanostructure-dependent functionality in complex media suggests that the pores with the optimal size and geometry act as sieves for blocking the biomolecules from inhibiting the surfaces within the porous volume while allowing the transport of nucleic acid analytes and redox molecules.

  12. Biofouling on buoyant marine plastics: An experimental study into the effect of size on surface longevity

    International Nuclear Information System (INIS)

    Fazey, Francesca M.C.; Ryan, Peter G.

    2016-01-01

    Recent estimates suggest that roughly 100 times more plastic litter enters the sea than is found floating at the sea surface, despite the buoyancy and durability of many plastic polymers. Biofouling by marine biota is one possible mechanism responsible for this discrepancy. Microplastics (<5 mm in diameter) are more scarce than larger size classes, which makes sense because fouling is a function of surface area whereas buoyancy is a function of volume; the smaller an object, the greater its relative surface area. We tested whether plastic items with high surface area to volume ratios sank more rapidly by submerging 15 different sizes of polyethylene samples in False Bay, South Africa, for 12 weeks to determine the time required for samples to sink. All samples became sufficiently fouled to sink within the study period, but small samples lost buoyancy much faster than larger ones. There was a direct relationship between sample volume (buoyancy) and the time to attain a 50% probability of sinking, which ranged from 17 to 66 days of exposure. Our results provide the first estimates of the longevity of different sizes of plastic debris at the ocean surface. Further research is required to determine how fouling rates differ on free floating debris in different regions and in different types of marine environments. Such estimates could be used to improve model predictions of the distribution and abundance of floating plastic debris globally. - Highlights: • We tested how fragment size affects the rate of buoyancy loss at sea due to biofouling for two low-density plastic polymers. • We found a strong direct relationship between fragment size and surface longevity. • Our longevity estimates ranged from 17 days for the thinnest microplastics to 66 days for thicker macroplastics. • Our results provide the first estimates of the longevity of different sizes of plastic debris at the ocean surface. • The results could be used to improve model predictions of the

  13. Impact of reverse nutrient diffusion on membrane biofouling in fertilizer-drawn forward osmosis

    KAUST Repository

    Li, Sheng

    2017-05-31

    Biofouling in fertilizer-drawn forward osmosis (FDFO) for water reuse was investigated by spiking pure bacteria species Pseudomonas aeruginosa PAO1+GFP and using three different fertilizers KNO3, KCl and KH2PO4 as draw solutions. The performance of FO process for treating synthetic wastewater was assessed and their influence on the membrane fouling and in particular biofouling was evaluated relative to the type of different fertilizers used and their rates of reverse diffusion. FO performances using KNO3 as draw solute exhibited severer flux decline (63%) than when using KCl (45%) and KH2PO4 (30%). Membrane autopsy indicated that the mass of organic foulants and biomass on fouled membrane surface using KNO3 as draw solute (947.5mg/m2 biopolymers, 72µm biofilm thickness and 53.3mg/m2 adenosine triphosphate) were significantly higher than that using KCl (450mg/m2 biopolymers, 33µm biofilm thickness and 28.2mg/m2 ATP) and KH2PO4 (440mg/m2 biopolymers, 35µm biofilm thickness and 33.5mg/m2 ATP). This higher flux decline is likely related to the higher reverse diffusion of KNO3 (19.8g/m2/h) than KCl (5.1g/m2/h) and KH2PO4 (3.7g/m2/h). The reverse diffused potassium could promote the organics and bacterial adhesion on FO membrane via charge screening effect and compression of electrical double layer. Moreover, reverse diffused nitrate provided increased N:P nutrient ratio was favorable for the bacteria to grow on the feed side of the FO membrane.

  14. Advanced Monitoring and Characterization of Biofouling in Gravity-driven Membrane Filtration

    KAUST Repository

    Wang, Yiran

    2016-05-01

    Gravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) technologies. It operates at a low pressure by gravity, requiring a minimal energy. Thus, it exhibits a great potential for a decentralized system, conducting household in developing and transition countries. Biofouling is a universal problem in almost all membrane filtration applications, leading to the decrease in flux or the increase in transmembrane pressure depending on different operation mode. Air scoring or regular membrane cleaning has been utilized for fouling mitigation, which requires increased energy consumption as well as complicated operations. Besides, repeating cleaning will trigger the deterioration of membranes and shorten their lifetime, elevating cost expenditures accordingly. In this way, GDM filtration stands out from conventional MBR technologies in a long-term operation with relative stable flux, which has been observed in many studies. The objective of this study was to monitor the biofilm development on a flat sheet membrane submerged in a GDM reactor with constant gravitational pressure. Morphology of biofilm layer in a fixed position was acquired by an in-situ and on-line OCT (optical coherence tomography) scanning at regular intervals for both visual investigation and structure analysis. The calculated thickness and roughness were compared to the variation of flux, fouling resistance and permeate quality, showing expected consistency. At the end of experiment, the morphology of entire membrane surface was scanned and recorded by OCT. Membrane autopsy was carried out for biofilm composition analysis by total organic carbon (TOC) and liquid chromatography with organic carbon detection (LC-OCD). In addition, biomass concentration was obtained by flow cytometer and adenosine tri-phosphate (ATP) method. The data of biofilm components indicated a homogeneous biofilm structure formed after a long-term running of the GDM system, based on the morphology

  15. Coral-associated bacteria, quorum sensing disrupters, and the regulation of biofouling.

    Science.gov (United States)

    Golberg, Karina; Pavlov, Valentina; Marks, Robert S; Kushmaro, Ariel

    2013-01-01

    Marine biofouling, the settlement of microorganisms and macroorganisms on structures submerged in seawater, although economically detrimental, is a successful strategy for survival in hostile environments, where coordinated bacterial communities establish biofilms via the regulation of quorum sensing (QS) communication systems. The inhibition of QS activity among bacteria isolated from different coral species was investigated to gain further insight into its potency in the attenuation, or even the prevention, of undesirable biofouling on marine organisms. It is hypothesized that coral mucus/microorganism interactions are competitive, suggesting that the dominant communities secrete QS disruptive compounds. One hundred and twenty bacterial isolates were collected from healthy coral species and screened for their ability to inhibit QS using three bioreporter strains. Approximately 12, 11, and 24% of the isolates exhibited anti-QS activity against Escherichia coli pSB1075, Chromobacterium violaceum CV026, and Agrobacterium tumefaciens KYC55 indicator strains, respectively. Isolates with positive activity against the bioluminescent monitor strains were scanned via a cytotoxic/genotoxic, E. coli TV1061 and DPD2794 antimicrobial panel. Isolates detected by C. violaceum CV026 and A. tumefaciens KYC55 reporter strains were tested for their ability to inhibit the growth of these reporter strains, which were found to be unaffected. Tests of the Favia sp. coral isolate Fav 2-50-7 (>98% similarity to Vibrio harveyi) for its ability to attenuate the formation of biofilm showed extensive inhibitory activity against biofilms of Pseudomonas aeruginosa and Acinetobacter baumannii. To ascertain the stability and general structure of the active compound, cell-free culture supernatants exposed to an increasing temperature gradient or to digestion by proteinase K, were shown to maintain potent QS attenuation and the ability to inhibit the growth of biofilms. Mass spectrometry confirmed

  16. Control of biofouling on titanium condenser tubes with the use of electroless copper plating

    International Nuclear Information System (INIS)

    Anandkumar, B.; George, R.P.; Kamachi Mudali, U.; Ramachandran, D.

    2015-01-01

    In sea water environments titanium condenser tubes face serious issues of biofouling and biomineralization. Electroless plating of nanocopper film is attempted inside the tubes for the control of biofilm formation. Using advanced techniques like AFM, SEM, and XPS, electroless copper plated flat Ti specimens were characterized. Examination of Cu coated Ti surfaces using AFM and SEM showed more reduction in the microroughness compared to anodized Ti surface. Cu 2p 3/2 peak in XPS spectral analysis showed the shift in binding energy inferring the reduction of the hydroxide to metallic copper. Tubular specimens were exposed to sea water up to three months and withdrawn at monthly intervals to evaluate antibacterial activity and long term stability of the coating. Total viable counts and epifluorescence microscopy analyses showed two orders decrease in bacterial counts on copper coated Ti specimens when compared to as polished control Ti specimens. Molecular biology techniques like DGGE and protein expression analysis system were done to get insight into the community diversity and copper tolerance of microorganisms. DGGE gel bands clearly showed the difference in the bacterial diversity inferring from the 16S rRNA gene fragments (V3 regions). Protein analysis showed distinct protein spots appearing in electroless copper coated Ti biofilm protein samples in addition to protein spots common to both the biofilms of Cu coated and as polished Ti. The results indicated copper accumulating proteins in copper resistant bacterial species of biofilm. Reduced microroughness of the surface and toxic copper ions resulted in good biofouling control even after three months exposure to sea water. (author)

  17. Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: A novel platform for eco-friendly biofouling mitigation

    NARCIS (Netherlands)

    Wibisono, Yusuf; Yandi, Wetra; Golabi, Mohsen; Nugraha, Roni; Cornelissen, Emile; Kemperman, A.J.B.; Ederth, Thomas; Nijmeijer, Kitty

    2015-01-01

    ng is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a Hydrogel-coated feed spacer and two-phase flow cleaning. Neutral (polyHEMA-co-PEG10MA),

  18. Laser damage to marine plankton and its application to checking biofouling and invasion by aquatic species: a laboratory study.

    Science.gov (United States)

    Nandakumar, Kanavillil; Obika, Hideki; Sreekumari, Kurissery; Utsumi, Akihiro; Ooie, Toshihiko; Yano, Tetsuo

    2009-01-01

    In this laboratory study, the ability of low-power pulsed laser irradiation to kill planktonic organisms in a flowing water system was examined, thus, to test the possibility of using this technique as a water treatment strategy to reduce biofouling growth in condenser tubes of power plants and to reduce bioinvasion via the ballast water of ships. Two flow rates (4.6 and 9.0 l h(-1)) were tested on three planktonic organisms: two marine centric diatoms viz. Skeletonema costatum and Chaetoceros gracilis and a dinoflagellate, Heterocapsa circularisquama. A low-power pulsed laser irradiation at 532 nm with a fluence of 0.1 J cm(-2) from a frequency-doubled Nd:YAG laser was used as the irradiation source. The laser irradiation resulted in a heavy mortality of the test cells. The mortality observed was >90% for S. costatum and H. circularisqama and >70% for C. gracilis. The results suggest that laser irradiation has the potential to act as a water treatment strategy to reduce biofouling of condenser tubes in power plants as well as to reduce species invasion via the ballast water of ships.

  19. Principles of Biofouling Protection in Marine Sponges: A Model for the Design of Novel Biomimetic and Bio-inspired Coatings in the Marine Environment?

    NARCIS (Netherlands)

    Müller, W.E.G.; Wang, X.; Proksch, P.; Perry, C.C.; Osinga, R.; Gardères, J.; Schröder, H.C.

    2013-01-01

    The process of biofouling of marine structures and substrates, such as platforms or ship hulls, proceeds in multiple steps. Soon after the formation of an initial conditioning film, formed via the adsorption of organic particles to natural or manmade substrates, a population of different bacterial

  20. Effect of vessel voyage speed on survival of biofouling organisms: implications for translocation of non-indigenous marine species.

    Science.gov (United States)

    Coutts, Ashley D M; Piola, Richard F; Hewitt, Chad L; Connell, Sean D; Gardner, Jonathan P A

    2010-01-01

    This study experimentally determined the effect of different vessel voyage speeds (5, 10 and 18 knots = 2.6, 5.1 and 9.3 ms(-1), respectively) and morphological characteristics including growth form (solitary or colonial), profile (erect or encrusting) and structure (soft, hard or flexible) on the survival of a range of common biofouling organisms. A custom built hydrodynamic keel attached to the bottom of a 6 m aluminium powerboat was used to subject pre-fouled settlement plates for this purpose. Vessel speeds of 5 and 10 knots had little effect on the species richness of biofouling assemblages tested, however richness decreased by 50% following 18 knots treatments. Species percentage cover decreased with increasing speed across all speed treatments and this decrease was most pronounced at 10 and 18 knots, with cover reduced by 24 and 85% respectively. Survival was greatest for organisms with colonial, encrusting, hard and/or flexible morphological characteristics, and this effect increased with increasing speed. This study suggests that there is predictive power in forecasting future introductions if we can understand the extent to which such traits explain the world-wide distributions of non-indigenous species. Future introductions are a certainty and can only provide an increasing source of new information on which to test the validity of these predications.

  1. Mitigation of Membrane Biofouling in MBR Using a Cellulolytic Bacterium, Undibacterium sp. DM-1, Isolated from Activated Sludge.

    Science.gov (United States)

    Nahm, Chang Hyun; Lee, Seonki; Lee, Sang Hyun; Lee, Kibaek; Lee, Jaewoo; Kwon, Hyeokpil; Choo, Kwang-Ho; Lee, Jung-Kee; Jang, Jae Young; Lee, Chung-Hak; Park, Pyung-Kyu

    2017-03-28

    Biofilm formation on the membrane surface results in the loss of permeability in membrane bioreactors (MBRs) for wastewater treatment. Studies have revealed that cellulose is not only produced by a number of bacterial species but also plays a key role during formation of their biofilm. Hence, in this study, cellulase was introduced to a MBR as a cellulose-induced biofilm control strategy. For practical application of cellulase to MBR, a cellulolytic ( i.e ., cellulase-producing) bacterium, Undibacterium sp. DM-1, was isolated from a lab-scale MBR for wastewater treatment. Prior to its application to MBR, it was confirmed that the cell-free supernatant of DM-1 was capable of inhibiting biofilm formation and of detaching the mature biofilm of activated sludge and cellulose-producing bacteria. This suggested that cellulase could be an effective anti-biofouling agent for MBRs used in wastewater treatment. Undibacterium sp. DM-1-entrapping beads ( i.e ., cellulolytic-beads) were applied to a continuous MBR to mitigate membrane biofouling 2.2-fold, compared with an MBR with vacant-beads as a control. Subsequent analysis of the cellulose content in the biofilm formed on the membrane surface revealed that this mitigation was associated with an approximately 30% reduction in cellulose by cellulolytic-beads in MBR.

  2. Surface Functionalization of Polyethersulfone Membrane with Quaternary Ammonium Salts for Contact-Active Antibacterial and Anti-Biofouling Properties

    Directory of Open Access Journals (Sweden)

    Xiao Hu

    2016-05-01

    Full Text Available Biofilm is a significant cause for membrane fouling. Antibacterial-coated surfaces can inhibit biofilm formation by killing bacteria. In this study, polyethersulfone (PES microfiltration membrane was photografted by four antibiotic quaternary ammonium compounds (QACs separately, which were synthesized from dimethylaminoethyl methacrylate (DMAEMA by quaternization with butyl bromide (BB, octyl bromide (OB, dodecyl bromide (DB, or hexadecyl bromide (HB. XPS, ATR-FTIR, and SEM were used to confirm the surfaces’ composition and morphology. After modification, the pores on PES-g-DMAEMA-BB and PES-g-DMAEMA-OB were blocked, while PES-g-DMAEMA-DB and PES-g-DMAEMA-HB were retained. We supposed that DMAEMA-BB and DMAEMA-OB aggregated on the membrane surface due to the activities of intermolecular or intramolecular hydrogen bonds. Bacteria testing found the antibacterial activities of the membranes increased with the length of the substituted alkyl chain. Correspondingly, little bacteria were observed on PES-g-DMAEMA-DB and PES-g-DMAEMA-HB by SEM. The antifouling properties were investigated by filtration of a solution of Escherichia coli. Compared with the initial membrane, PES-g-DMAEMA-DB and PES-g-DMAEMA-HB showed excellent anti-biofouling performance with higher relative flux recovery (RFR of 88.3% and 92.7%, respectively. Thus, surface functionalization of the PES membrane with QACs can prevent bacteria adhesion and improve the anti-biofouling activity by the contact-active antibacterial property.

  3. Control of biofouling on reverse osmosis polyamide membranes modified with biocidal nanoparticles and antifouling polymer brushes

    KAUST Repository

    Rahaman, Md. Saifur

    2014-01-01

    Thin-film composite (TFC) polyamide reverse osmosis (RO) membranes are prone to biofouling due to their inherent physicochemical surface properties. In order to address the biofouling problem, we have developed novel surface coatings functionalized with biocidal silver nanoparticles (AgNPs) and antifouling polymer brushes via polyelectrolyte layer-by-layer (LBL) self-assembly. The novel surface coating was prepared with polyelectrolyte LBL films containing poly(acrylic acid) (PAA) and poly(ethylene imine) (PEI), with the latter being either pure PEI or silver nanoparticles coated with PEI (Ag-PEI). The coatings were further functionalized by grafting of polymer brushes, using either hydrophilic poly(sulfobetaine) or low surface energy poly(dimethylsiloxane) (PDMS). The presence of both LBL films and sulfobetaine polymer brushes at the interface significantly increased the hydrophilicity of the membrane surface, while PDMS brushes lowered the membrane surface energy. Overall, all surface modifications resulted in significant reduction of irreversible bacterial cell adhesion. In microbial adhesion tests with E. coli bacteria, a normalized cell adhesion in the range of only 4 to 16% on the modified membrane surfaces was observed. Modified surfaces containing silver nanoparticles also exhibited strong antimicrobial activity. Membranes coated with LBL films of PAA/Ag-PEI achieved over 95% inactivation of bacteria attached to the surface within 1 hour of contact time. Both the antifouling and antimicrobial results suggest the potential of using these novel surface coatings in controlling the fouling of RO membranes. © The Royal Society of Chemistry 2014.

  4. Mitigation of membrane biofouling by a quorum quenching bacterium for membrane bioreactors.

    Science.gov (United States)

    Ham, So-Young; Kim, Han-Shin; Cha, Eunji; Park, Jeong-Hoon; Park, Hee-Deung

    2018-06-01

    In this study, a quorum-quenching (QQ) bacterium named HEMM-1 was isolated at a membrane bioreactor (MBR) plant. HEMM-1 has diplococcal morphology and 99% sequence identity to Enterococcus species. The HEMM-1 cell-free supernatant (CFS) showed higher QQ activities than the CFS of other QQ bacteria, mostly by degrading N-acyl homoserine lactones (AHLs) with short acyl chains. Instrumental analyses revealed that HEMM-1 CFS degraded AHLs via lactonase activity. Under static, flow, and shear conditions, the HEMM-1 CFS was effective in reducing bacterial and activated-sludge biofilms formed on membrane surfaces. In conclusion, the HEMM-1 isolate is a QQ bacterium applicable to the control of biofouling in MBRs via inhibition of biofilm formation on membrane surfaces. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Use of ceragenins to create novel biofouling resistant water-treatment membranes.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Altman, Susan Jeanne; Feng, Yanshu (Brigham Young University, Provo, UT); Savage, Paul B. (Brigham Young University, Provo, UT); Pollard, Jacob (Brigham Young University, Provo, UT); Sanchez, Andres L. (LMATA, Albuquerque, NM); Fellows, Benjamin D.; Jones, Howland D. T.; McGrath, Lucas K. (LMATA, Albuquerque, NM)

    2008-12-01

    Scoping studies have demonstrated that ceragenins, when linked to water-treatment membranes have the potential to create biofouling resistant water-treatment membranes. Ceragenins are synthetically produced molecules that mimic antimicrobial peptides. Evidence includes measurements of CSA-13 prohibiting the growth of and killing planktonic Pseudomonas fluorescens. In addition, imaging of biofilms that were in contact of a ceragenin showed more dead cells relative to live cells than in a biofilm that had not been treated with a ceragenin. This work has demonstrated that ceragenins can be attached to polyamide reverse osmosis (RO) membranes, though work needs to improve the uniformity of the attachment. Finally, methods have been developed to use hyperspectral imaging with multivariate curve resolution to view ceragenins attached to the RO membrane. Future work will be conducted to better attach the ceragenin to the RO membranes and more completely test the biocidal effectiveness of the ceragenins on the membranes.

  6. The effect of feed salinity on the biofouling dynamics of seawater desalination.

    Science.gov (United States)

    Yang, Hui-Ling; Pan, Jill R; Huang, Chihpin; Lin, Justin Chun-Te

    2011-05-01

    A persistent cell labeling dye and a novel microbial counting method were used to explore the effects of salinity on a microbial population in a reverse osmosis (RO) desalination system, and these clearly distinguished microbial cell multiplication from cell adherence. The results indicated that microbial multiplication is more active at the front of a seawater RO pressure vessel, while adhesion dominates the back of the vessel. A severe reduction in RO permeate flux and total dissolved solid (TDS) rejection were detected at low salinity, attributed to marked cell multiplication and release of extracellular polymeric substances, whilst a relatively stable flux was observed at medium and high salinity. The results from PCR-DGGE revealed the variation in microbial species distribution on the membrane with salinity. The results imply the critical role of membrane modification in biofouling mitigation in the desalination process.

  7. Preparation and performance of biofouling resistant PAN/chitosan hollow fiber membranes.

    Science.gov (United States)

    Shanthana Lakshmi, D; Jaiswar, Santlal; Saxena, Mayank; Tasselli, Franco; Raval, Hiren D

    2017-07-01

    The preparation of polyacrylonitrile (PAN) hollow fiber (HF) membranes has been carried out by dry-jet wet spinning. PAN HF membranes were coated with chitosan biopolymers 2 wt% by dip coating and further crosslinked by chemical reagents (Tri sodium polyphosphate). PAN HF (Virgin) and PAN/chitosan coated membrane were characterized by SEM and tested for water flux. Proteins Pepsin, Albumin, and Clay of 1000 ppm concentration were tested for separation efficiency. In addition, bacterial species Escherichia coli and Bacillus subtilis were tested for fouling control efficiency and found out that PAN/chitosan membranes were quite superior to virgin PAN fibers. The adhesion of bacterial cells on the surface of the hollow fiber membranes assessed through alcian blue staining and SEM analysis. It was observed that PAN/chitosan membranes (310A and 310C) possessed best antibacterial activities (based on SEM results), qualifying them as a very promising candidates for anti-biofouling coatings.

  8. Influence of the chemical composition, heat and surface treatment in the biofouling of austenitic stainless steels; Influencia de la composicion quimica, del tratamiento termico y del acabado supreficial en el bioensuciamiento de aceros inoxidables austeniticos

    Energy Technology Data Exchange (ETDEWEB)

    Sarro, M. I.; Aleman, O.; Moreno, D. A.; Roso, M.; Ranninger, C.

    2004-07-01

    The main objective of this study was to analyse the biofouling processes in the kinds of stainless steels used normally in industry (UNS S30400, UNS S30403 and UNS S31600), with different surface treatments after grinding and polishing. The study was developed using two microscopy techniques. Scanning Electron Microscopy (SEM) was used to evaluate the microorganisms distribution in the materials, and Epi fluorescence Microscopy was used to evaluate the viability of cells in the biofilm. The results revealed the influence of the material, heat treatment, surface treatment and roughness in the biofouling processes in the stainless steel assays. (Author) 33 refs.

  9. Evidence of compositional and ultrastructural shifts during the development of calcareous tubes in the biofouling tubeworm, Hydroides elegans.

    Science.gov (United States)

    Chan, Vera Bin San; Vinn, Olev; Li, Chaoyi; Lu, Xingwen; Kudryavtsev, Anatoliy B; Schopf, J William; Shih, Kaimin; Zhang, Tong; Thiyagarajan, Vengatesen

    2015-03-01

    The serpulid tubeworm, Hydroides elegans, is an ecologically and economically important species whose biology has been fairly well studied, especially in the context of larval development and settlement on man-made objects (biofouling). Nevertheless, ontogenetic changes associated with calcareous tube composition and structures have not yet been studied. Here, the ultrastructure and composition of the calcareous tubes built by H. elegans was examined in the three early calcifying juvenile stages and in the adult using XRD, FTIR, ICP-OES, SEM and Raman spectroscopy. Ontogenetic shifts in carbonate mineralogy were observed, for example, juvenile tubes contained more amorphous calcium carbonate and were predominantly aragonitic whereas adult tubes were bimineralic with considerably more calcite. The mineral composition gradually shifted during the tube development as shown by a decrease in Sr/Ca and an increase of Mg/Ca ratios with the tubeworm's age. The inner tube layer contained calcite, whereas the outer layer contained aragonite. Similarly, the tube complexity in terms of ultrastructure was associated with development. The sequential appearance of unoriented ultrastructures followed by oriented ultrastructures may reflect the evolutionary history of serpulid tube biominerals. As aragonitic structures are more susceptible to dissolution under ocean acidification (OA) conditions but are more difficult to be removed by anti-fouling treatments, the early developmental stages of the tubeworms may be vulnerable to OA but act as the important target for biofouling control. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Effectiveness of Devices to Monitor Biofouling and Metals Deposition on Plumbing Materials Exposed to a Full-Scale Drinking Water Distribution System

    OpenAIRE

    Ginige, Maneesha P.; Garbin, Scott; Wylie, Jason; Krishna, K. C. Bal

    2017-01-01

    A Modified Robbins Device (MRD) was installed in a full-scale water distribution system to investigate biofouling and metal depositions on concrete, high-density polyethylene (HDPE) and stainless steel surfaces. Bulk water monitoring and a KIWA monitor (with glass media) were used to offline monitor biofilm development on pipe wall surfaces. Results indicated that adenosine triphosphate (ATP) and metal concentrations on coupons increased with time. However, bacterial diversities decreased. Th...

  11. Revealing Amphiphilic Nanodornains of Anti-Biofouling Polymer Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Amadei, CA; Yang, R; Chiesa, M; Gleason, KK; Santos, S

    2014-04-09

    Undesired bacterial adhesion and biofilm formation on wetted surfaces leads to significant economic and environmental costs in various industries. Amphiphilic coatings with molecular hydrophilic and hydrophobic patches can mitigate such biofouling effectively in an environmentally friendly manner. The coatings are synthesized by copolymerizing (Hydroxyethyl)methacrylate and perfluorodecylacrylate via initiated chemical vapor deposition (iCVD). In previous studies, the size of the patches was estimated to be similar to 1.4-1.75 nm by fitting protein adsorption data to a theoretical model. However, no direct observations of the molecular heterogeneity exist and therefore the origin of the fouling resistance of amphiphilic coatings remains unclear. Here, the amphiphilic nature is investigated by amplitude modulation atomic force microscopy (AM-AFM). High-resolution images obtained by penetrating and oscillating the AFM tip under the naturally present water layer with sub-nanometer amplitudes reveal, for the first time, the existence of amphiphilic nanodomains (1-2 nm(2)). Compositional heterogeneity at the nanoscale is further corroborated by a statistical analysis on the data obtained with dynamic AM-AFM force spectroscopy. Variations in the long range attractive forces, responsible for water affinity, are also identified. These nanoscopic results on the polymers wettability are also confirmed by contact angle measurements (i.e., static and dynamic). The unprecedented ability to visualize the amphiphilic nanodomains as well as sub-nanometer crystalline structures provides strong evidence for the existence of previously postulated nanostructures, and sheds light on the underlying antifouling mechanism of amphiphilic chemistry.

  12. Biofouling of reverse-osmosis membranes under different shear rates during tertiary wastewater desalination: microbial community composition.

    Science.gov (United States)

    Al Ashhab, Ashraf; Gillor, Osnat; Herzberg, Moshe

    2014-12-15

    We investigated the influence of feed-water shear rate during reverse-osmosis (RO) desalination on biofouling with respect to microbial community composition developed on the membrane surface. The RO membrane biofilm's microbial community profile was elucidated during desalination of tertiary wastewater effluent in a flat-sheet lab-scale system operated under high (555.6 s(-1)), medium (370.4 s(-1)), or low (185.2 s(-1)) shear rates, corresponding to average velocities of 27.8, 18.5, and 9.3 cm s(-1), respectively. Bacterial diversity was highest when medium shear was applied (Shannon-Weaver diversity index H' = 4.30 ± 0.04) compared to RO-membrane biofilm developed under lower and higher shear rates (H' = 3.80 ± 0.26 and H' = 3.42 ± 0.38, respectively). At the medium shear rate, RO-membrane biofilms were dominated by Betaproteobacteria, whereas under lower and higher shear rates, the biofilms were dominated by Alpha- and Gamma- Proteobacteria, and the latter biofilms also contained Deltaproteobacteria. Bacterial abundance on the RO membrane was higher at low and medium shear rates compared to the high shear rate: 8.97 × 10(8) ± 1.03 × 10(3), 4.70 × 10(8) ± 1.70 × 10(3) and 5.72 × 10(6) ± 2.09 × 10(3) copy number per cm(2), respectively. Interestingly, at the high shear rate, the RO-membrane biofilm's bacterial community consisted mainly of populations known to excrete high amounts of extracellular polymeric substances. Our results suggest that the RO-membrane biofilm's community composition, structure and abundance differ in accordance with applied shear rate. These results shed new light on the biofouling phenomenon and are important for further development of antibiofouling strategies for RO membranes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Polysulfobetaine films prepared by electrografting technique for reduction of biofouling on electroconductive surfaces

    International Nuclear Information System (INIS)

    Stach, Marek; Kronekova, Zuzana; Kasak, Peter; Kollar, Jozef; Pentrak, Martin; Micusik, Matej; Chorvat, Dusan; Nunney, Tim S.; Lacik, Igor

    2011-01-01

    The sulfobetaine films were prepared on stainless steel and golden surfaces. In the first step, the poly(2-(dimethylamino)ethyl methacrylate) film was created by employing the electrografting polymerization technique. In the second step, this film was modified to polysulfobetaine, i.e. the polymer film bearing the zwitterionic groups. The presence of the electrografted film and its modification were determined by contact angle measurements, infrared spectroscopy in reflectance mode and X-ray photoelectron spectroscopy. The prepared films were homogeneous with the thickness from about 5 to 26 nm as determined by X-ray photoelectron spectroscopy. The atomic force microscopy measurements showed the increase of surface roughness upon the surface coating. In vitro tests using adherent RAT-2 fibroblast cells and fluorescently labelled bovine serum albumin proteins showed that prepared polysulfobetaine films can be used in applications requiring the resistance against cell attachment and biofouling.

  14. Development and testing of a transparent membrane biofouling monitor

    KAUST Repository

    Dreszer, C.; Flemming, Hans Curt; Wexler, Adam D.; Zwijnenburg, Arie; Kruithof, Joop C.; Vrouwenvelder, Johannes S.

    2014-01-01

    A modified version of the membrane fouling simulator (MFS) was developed for assessment of (i) hydraulic biofilm resistance, (ii) performance parameters feed-channel pressure drop and transmembrane pressure drop, and (iii) in situ spatial visual and optical observations of the biofilm in the transparent monitor, e.g. using optical coherence tomography. The flow channel height equals the feed spacer thickness enabling operation with and without feed spacer. The effective membrane surface area was enlarged from 80 to 200 cm2 by increasing the monitor width compared to the standard MFS, resulting in larger biomass amounts for analysis. By use of a microfiltration membrane (pore size 0.05 μm) in the monitor salt concentration polarization is avoided, allowing operation at low pressures enabling accurate measurement of the intrinsic hydraulic biofilm resistance. Validation tests on e.g. hydrodynamic behavior, flow field distribution, and reproducibility showed that the small-sized monitor was a representative tool for membranes used in practice under the same operating conditions, such as spiral-wound nanofiltration and reverse osmosis membranes. Monitor studies with and without feed spacer use at a flux of 20 L m-2 h-1 and a cross-flow velocity of 0.1 m s-1 clearly showed the suitability of the monitor to determine hydraulic biofilm resistance and for controlled biofouling studies. © 2013 Balaban Desalination Publications. All rights reserved.

  15. Development and testing of a transparent membrane biofouling monitor

    KAUST Repository

    Dreszer, C.

    2014-01-02

    A modified version of the membrane fouling simulator (MFS) was developed for assessment of (i) hydraulic biofilm resistance, (ii) performance parameters feed-channel pressure drop and transmembrane pressure drop, and (iii) in situ spatial visual and optical observations of the biofilm in the transparent monitor, e.g. using optical coherence tomography. The flow channel height equals the feed spacer thickness enabling operation with and without feed spacer. The effective membrane surface area was enlarged from 80 to 200 cm2 by increasing the monitor width compared to the standard MFS, resulting in larger biomass amounts for analysis. By use of a microfiltration membrane (pore size 0.05 μm) in the monitor salt concentration polarization is avoided, allowing operation at low pressures enabling accurate measurement of the intrinsic hydraulic biofilm resistance. Validation tests on e.g. hydrodynamic behavior, flow field distribution, and reproducibility showed that the small-sized monitor was a representative tool for membranes used in practice under the same operating conditions, such as spiral-wound nanofiltration and reverse osmosis membranes. Monitor studies with and without feed spacer use at a flux of 20 L m-2 h-1 and a cross-flow velocity of 0.1 m s-1 clearly showed the suitability of the monitor to determine hydraulic biofilm resistance and for controlled biofouling studies. © 2013 Balaban Desalination Publications. All rights reserved.

  16. Biofouling of granite-rapakivi in St. Petersburg monuments and in the quarry in Russia and Finland

    Science.gov (United States)

    Vlasov, Dmitry; Panova, Elena; Alampieva, Elena; Olhovaya, Elena; Popova, Tatyana; Vlasov, Alexey; Zelenskaya, Marina

    2013-04-01

    Granite-rapakivi was widely used in the architecture of St. Petersburg: the facades of buildings, embankments of rivers and canals, bridges, sculptural monuments, pedestals, facing the metro stations. This stone is rapidly destroyed due to the peculiarities of its structure. Biofouling of granite is insufficiently studied. Cause the destruction of granite can be bacteria, microscopic algae, fungi, mosses, lichens, higher plants, invertebrates and vertebrates. They often form specific lithobiotic communities that contribute to the destruction of granite-rapakivi. The objects of research were monuments of St. Petersburg (granite sculpture, facades, facing embankments) as well as granite-rapakivi quarries in Russia and Finland, where the stone was quarried for use in St. Petersburg. Sampling was carried out from the most typical biofouling sites. Different methods were applied for the study of damaged granite: petrographic analysis, light and scanning electron microscopy, methods for detection and identification of microorganisms, X-ray microprobe analysis. As result the main forms of granite destruction were described: fractures, ovoid weathering, granular disintegration, surface films, crusts and layers, pitting and fouling. Lichens, mosses, herbaceous and micromycetes were dominated on the granite-rapakivi in quarries. For example, in a Monferran quarry (Virolahti region) the complicated lithobiotic community was revealed. It included 30 species of micromycetes, 31 species of lichens, 10 species of moss. Bacteriological analysis showed the dominance of bacteria Bacillus, and actinomycetes in microbial biofilms. More than 100 species of plants were found on the granite embankments in St. Petersburg. They were confined to the cracks, seams of granite blocks. Plants and mosses were common to the granite embankments of rivers and canals in the central (historical) part of the city. Dimensions of mosses depend on the area of the deepening which they occupy. The most

  17. 2D Gel-Based Multiplexed Proteomic Analysis during Larval Development and Metamorphosis of the Biofouling Polychaete Tubeworm Hydroides elegans

    KAUST Repository

    Zhang, Yu; Sun, Jin; Xiao, Kang; Arellano, Shawn M.; Thiyagarajan, Vengatesen; Qian, Pei Yuan

    2010-01-01

    Larval settlement and metamorphosis of a common biofouling polychaete worm, Hydroides elegans, involve remarkable structural and physiological changes during this pelagic to sessile habitat shift. The endogenous protein molecules and post-translational modifications that drive this larval transition process are not only of interest to ecologists but also to the antifouling paint industry, which aims to control the settlement of this biofouling species on man-made structures (e.g., ship hulls). On the basis of our recent proteomic studies, we hypothesize that rapid larval settlement of H. elegans could be mediated through changes in phosphorylation status of proteins rather than extensive de novo synthesis of proteins. To test this hypothesis, 2D gel-based multiplexed proteomics technology was used to monitor the changes in protein expression and phosphorylation status during larval development and metamorphosis of H. elegans. The protein expression profiles of larvae before and after they reached competency to attach and metamorphose were similar in terms of major proteins, but the percentage of phosphorylated proteins increased from 41% to 49% after competency. Notably, both the protein and phosphoprotein profiles of the metamorphosed individuals (adult) were distinctly different from that of the larvae, with only 40% of the proteins phosphorylated in the adult stage. The intensity ratio of all phosphoprotein spots to all total protein spots was also the highest in the competent larval stage. Overall, our results indicated that the level of protein phosphorylation might play a crucial role in the initiation of larval settlement and metamorphosis. © 2010 American Chemical Society.

  18. 2D Gel-Based Multiplexed Proteomic Analysis during Larval Development and Metamorphosis of the Biofouling Polychaete Tubeworm Hydroides elegans

    KAUST Repository

    Zhang, Yu

    2010-09-03

    Larval settlement and metamorphosis of a common biofouling polychaete worm, Hydroides elegans, involve remarkable structural and physiological changes during this pelagic to sessile habitat shift. The endogenous protein molecules and post-translational modifications that drive this larval transition process are not only of interest to ecologists but also to the antifouling paint industry, which aims to control the settlement of this biofouling species on man-made structures (e.g., ship hulls). On the basis of our recent proteomic studies, we hypothesize that rapid larval settlement of H. elegans could be mediated through changes in phosphorylation status of proteins rather than extensive de novo synthesis of proteins. To test this hypothesis, 2D gel-based multiplexed proteomics technology was used to monitor the changes in protein expression and phosphorylation status during larval development and metamorphosis of H. elegans. The protein expression profiles of larvae before and after they reached competency to attach and metamorphose were similar in terms of major proteins, but the percentage of phosphorylated proteins increased from 41% to 49% after competency. Notably, both the protein and phosphoprotein profiles of the metamorphosed individuals (adult) were distinctly different from that of the larvae, with only 40% of the proteins phosphorylated in the adult stage. The intensity ratio of all phosphoprotein spots to all total protein spots was also the highest in the competent larval stage. Overall, our results indicated that the level of protein phosphorylation might play a crucial role in the initiation of larval settlement and metamorphosis. © 2010 American Chemical Society.

  19. Marine biofouling and its implications in the use of seawater as a heat transfer fluid in Madras Atomic Power Station

    International Nuclear Information System (INIS)

    Nair, K.V.K.; Venugopalan, V.P.

    1996-01-01

    Even though the problem of fouling is quite severe in the tropics because of rich diversity of species and longer periods available for breeding activity, most of the literature is from the temperate waters. In this paper, an attempt is made to illustrate the potential of biofouling to compromise the economical operation of coastal power plants by taking Madras Atomic Power Station (MAPS) as an example. The significance of acquiring information on biological aspects of the fouling species in successfully combating the problems is also highlighted. 3 refs., 3 tabs., 1 fig

  20. Control of biofouling by xanthine oxidase on seawater reverse osmosis membranes from a desalination plant: enzyme production and screening of bacterial isolates from the full-scale plant.

    Science.gov (United States)

    Nagaraj, V; Skillman, L; Li, D; Xie, Z; Ho, G

    2017-07-01

    Control of biofouling on seawater reverse osmosis (SWRO) membranes is a major challenge as treatments can be expensive, damage the membrane material and often biocides do not remove the polymers in which bacteria are embedded. Biological control has been largely ignored for biofouling control. The objective of this study was to demonstrate the effectiveness of xanthine oxidase enzyme against complex fouling communities and then identify naturally occurring bacterial strains that produce the free radical generating enzyme. Initially, 64 bacterial strains were isolated from different locations of the Perth Seawater Desalination Plant. In our preceding study, 25/64 isolates were selected from the culture collection as models for biofouling studies, based on their prevalence in comparison to the genomic bacterial community. In this study, screening of these model strains was performed using a nitroblue tetrazolium assay in the presence of hypoxanthine as substrate. Enzyme activity was measured by absorbance. Nine of 25 strains tested positive for xanthine oxidase production, of which Exiguobacterium from sand filters and Microbacterium from RO membranes exhibited significant levels of enzyme production. Other genera that produced xanthine oxidase were Marinomonas, Pseudomonas, Bacillus, Pseudoalteromonas and Staphylococcus. Strain variations were observed between members of the genera Microbacterium and Bacillus. Xanthine oxidase, an oxidoreductase enzyme that generates reactive oxygen species, is endogenously produced by many bacterial species. In this study, production of the enzyme by bacterial isolates from a full-scale desalination plant was investigated for potential use as biological control of membrane fouling in seawater desalination. We have previously demonstrated that free radicals generated by a commercially available xanthine oxidase in the presence of a hypoxanthine substrate, effectively dispersed biofilm polysaccharides on industrially fouled membranes

  1. Prevention and protection of the effects of biocorrosion and biofouling minimizing the environmental impact

    Directory of Open Access Journals (Sweden)

    Gómez de Saravia, S. G.

    2003-12-01

    Full Text Available Biocorrosion and biofouling processes are mediated by microorganisms adhered to the metal surfaces or embedded in a gelatinous matrix called biofilm. Biofilms affect the interaction between metals and the environment not only in deleterious processes like corrosion but also in several biological processes applied to materials recovery and handling. The growth of the microorganisms capable to induce biocorrosion is conditioned by favorable environmental conditions. However, the chemical agents generally used to prevent or protect metallic structures from biocorrosion are highly toxic and after use can have a negative impact on the environment. Four different approaches developed in our laboratory to prevent and control biocorrosion but minimizing the environmental impact, are successively presented in this paper: a the use of ozone as an environmentally friend biocide for cooling water systems; b the assay of the effectiveness of natural biocides on planktonic and sessile bacteria; c the potential use of film forming corrosion inhibitors; d the use of innovative preventing substances.

    Los procesos de biocorrosión y biofouling están mediados por microorganismos que adhieren a las superficies metálicas embebidos en una matriz gelatinosa llamada biofilm. Los biofilms afectan a la interacción entre metales y el medio ambiente, no solo a través de procesos deletéreos tales como la corrosión sino, también, en el manipuleo de diversos materiales. El crecimiento de los microorganismos capaces de inducir biocorrosión esta condicionado por un medio ambiente favorable. Sin embargo, generalmente, los agentes químicos usados para prevenir o proteger las estructuras metálicas de la biocorrosión son altamente tóxicos y su uso puede tener un impacto negativo para el ambiente. En este trabajo se presentan cuatro vías diferentes, desarrolladas en nuestro laboratorio, para prevenir y controlar la biocorrosión minimizando el impacto

  2. Prevención y protección de los efectos de la biocorrosión y el biofouling con mínimo impacto ambiental

    OpenAIRE

    Saravia, Sandra Gómez de; Guiamet, Patricia; Videla, Héctor A.

    2003-01-01

    Biocorrosion and biofouling processes are mediated by microorganisms adhered to the metal surfaces or embedded in a gelatinous matrix called biofilm. Biofilms affect the interaction between metals and the environment not only in deleterious processes like corrosion but also in several biological processes applied to materials recovery and handling. The growth of the microorganisms capable to induce biocorrosion is conditioned by favorable environmental conditions. However, the chemical agents...

  3. Cross-species induction of antimicrobial compounds, biosurfactants and quorum-sensing inhibitors in tropical marine epibiotic bacteria by pathogens and biofouling microorganisms.

    Science.gov (United States)

    Dusane, Devendra H; Matkar, Pratiek; Venugopalan, Valayam P; Kumar, Ameeta Ravi; Zinjarde, Smita S

    2011-03-01

    Enhancement or induction of antimicrobial, biosurfactant, and quorum-sensing inhibition property in marine bacteria due to cross-species and cross-genera interactions was investigated. Four marine epibiotic bacteria (Bacillus sp. S3, B. pumilus S8, B. licheniformis D1, and Serratia marcescens V1) displaying antimicrobial activity against pathogenic or biofouling fungi (Candida albicans CA and Yarrowia lipolytica YL), and bacteria (Pseudomonas aeruginosa PA and Bacillus pumilus BP) were chosen for this study. The marine epibiotic bacteria when co-cultivated with the aforementioned fungi or bacteria showed induction or enhancement in antimicrobial activity, biosurfactant production, and quorum-sensing inhibition. Antifungal activity against Y. lipolytica YL was induced by co-cultivation of the pathogens or biofouling strains with the marine Bacillus sp. S3, B. pumilus S8, or B. licheniformis D1. Antibacterial activity against Ps. aeruginosa PA or B. pumilus BP was enhanced in most of the marine isolates after co-cultivation. Biosurfactant activity was significantly increased when cells of B. pumilus BP were co-cultivated with S. marcescens V1, B. pumilus S8, or B. licheniformis D1. Pigment reduction in the quorum-sensing inhibition indicator strain Chromobacterium violaceum 12472 was evident when the marine strain of Bacillus sp. S3 was grown in the presence of the inducer strain Ps. aeruginosa PA, suggesting quorum-sensing inhibition. The study has important ecological and biotechnological implications in terms of microbial competition in natural environments and enhancement of secondary metabolite production.

  4. Assessment of biofouling community development on test panels submerged in Kudankulam coast with special reference to the Nuclear Power Project

    International Nuclear Information System (INIS)

    Satheesh, S.; Wesley, S. Godwin

    2008-01-01

    Biofouling is known to be one of the common problems in cooling water systems of power plants and several incidents of plant shutdown have been reported from various parts of the world. The settlement of marine organisms on an exposed hard surface depends obviously on the species, which are naturally present at a given site as well as their ability to attach and grow on that surface. Information on the organisms forming the fouling complex is necessary in view of the damages they cause to various marine structures and for devising protective measures. The present paper reports the results of the investigations of biofouling carried out for a period of two years from November 2003 to October 2004 at Kudankulam coast where a mega nuclear power project is under construction. Wooden test panels (10x10x3 cm) were fitted to a raft and submerged in the coastal waters. Total fouling biomass, thickness, coverage and community composition were analysed from the panels. Barnacles, mussels, ascidians, polychaetes, amphipods and seaweeds were the common fouling groups settled on the test panels. The total biomass reached to a maximum of 69.9 g.dm -2 (dry weight) after 330 days of exposure. The fouling thickness reached a maximum of 42.3 mm after 225 days of exposure. Results also showed a strong temporal variation in the fouling community recruitment. Based on the observations, Kudankulam coast could be categorized as a moderate fouling station mainly due to the low abundance of mussels in this region. (author)

  5. Growth behaviors of bacteria in biofouling cake layer in a dead-end microfiltration system.

    Science.gov (United States)

    Chao, Yuanqing; Zhang, Tong

    2011-01-01

    The growth behaviors of three bacterial species, i.e. Escherichia coli, Pseudomonas putida and Aquabaculum hongkongensis, in biofouling cake layer (attached form) were investigated using an unstirred dead-end continuous microfiltration system, and were compared with those in suspended form. Results showed that all the three bacteria had larger average growth rates in suspended form than in attached form under high substrates levels. Under oligotrophic conditions, the average growth rates in the attached form were faster than those in the suspended form, especially for A. hongkongensis. The growth behaviors analysis presented the same results due to all the tested bacteria had higher maximum growth rate and saturation constant in suspended form than attached form, indicating the dominant growth mode would be shifted from attached form to suspended form with substrate concentration increase. Finally, total filtration resistance determined in the experiments increased significantly with the bacterial growth in filtration system. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Membrane biofouling characterization: effects of sample preparation procedures on biofilm structure and the microbial community

    KAUST Repository

    Xue, Zheng

    2014-07-15

    Ensuring the quality and reproducibility of results from biofilm structure and microbial community analysis is essential to membrane biofouling studies. This study evaluated the impacts of three sample preparation factors (ie number of buffer rinses, storage time at 4°C, and DNA extraction method) on the downstream analysis of nitrifying biofilms grown on ultrafiltration membranes. Both rinse and storage affected biofilm structure, as suggested by their strong correlation with total biovolume, biofilm thickness, roughness and the spatial distribution of EPS. Significant variations in DNA yields and microbial community diversity were also observed among samples treated by different rinses, storage and DNA extraction methods. For the tested biofilms, two rinses, no storage and DNA extraction with both mechanical and chemical cell lysis from attached biofilm were the optimal sample preparation procedures for obtaining accurate information about biofilm structure, EPS distribution and the microbial community. © 2014 © 2014 Taylor & Francis.

  7. On microalgal settlements and the sluggish development of marine biofouling in Port Blair waters, Andamans.

    Science.gov (United States)

    Eashwar, M; Nallathambi, T; Kuberaraj, K

    2008-01-01

    Settlement of microalgae was investigated on Perspex, aluminium and zinc coupons immersed in Port Blair Bay waters for over 3 months. Commencement of fouling was exceptionally slow, and few microalgae were found until 14 days. Settlement occurred thereafter, and 47 microalgal species contributed to the fouling. The dominant forms belonged to the genera Navicula and Nitzschia, whereas Coscinodiscus eccentricus, Gyrosigma balticum and Trichodesmium erythraeum also accounted for high proportions of the settlements. The dominance of Nitzschia sigma was particularly marked on zinc coupons, suggesting an ability by the organism to resist toxicity. Settlement of both centric and pennate diatoms was observed in the early and mid periods, and absolute dominance of the pennate diatoms subsequently. The fouling mass was low even after 103 days, and it is speculated that strong ultraviolet radiation might be the prime reason for the sluggish development of marine biofouling in these oceanic island waters.

  8. Influence of Electric Fields on Biofouling of Carbonaceous Electrodes.

    Science.gov (United States)

    Pandit, Soumya; Shanbhag, Sneha; Mauter, Meagan; Oren, Yoram; Herzberg, Moshe

    2017-09-05

    Biofouling commonly occurs on carbonaceous capacitive deionization electrodes in the process of treating natural waters. Although previous work reported the effect of electric fields on bacterial mortality for a variety of medical and engineered applications, the effect of electrode surface properties and the magnitude and polarity of applied electric fields on biofilm development has not been comprehensively investigated. This paper studies the formation of a Pseudomonas aeruginosa biofilm on a Papyex graphite (PA) and a carbon aerogel (CA) in the presence and the absence of an electric field. The experiments were conducted using a two-electrode flow cell with a voltage window of ±0.9 V. The CA was less susceptible to biofilm formation compared to the PA due to its lower surface roughness, lower hydrophobicity, and significant antimicrobial properties. For both positive and negative applied potentials, we observed an inverse relationship between biofilm formation and the magnitude of the applied potential. The effect is particularly strong for the CA electrodes and may be a result of cumulative effects between material toxicity and the stress experienced by cells at high applied potentials. Under the applied potentials for both electrodes, high production of endogenous reactive oxygen species (ROS) was indicative of bacterial stress. For both electrodes, the elevated specific ROS activity was lowest for the open circuit potential condition, elevated when cathodically and anodically polarized, and highest for the ±0.9 V cases. These high applied potentials are believed to affect the redox potential across the cell membrane and disrupt redox homeostasis, thereby inhibiting bacterial growth.

  9. Physicochemical properties and membrane biofouling of extra-cellular polysaccharide produced by a Micrococcus luteus strain.

    Science.gov (United States)

    Feng, Lei; Li, Xiufen; Song, Ping; Du, Guocheng; Chen, Jian

    2014-07-01

    The physicochemical properties of the extra-cellular polysaccharide (EPS) produced by a Micrococcus luteus strain, a dominating strain isolated from membrane biofouling layer, were determined in this study. The EPS isolated from this strain was measured to have an average molecular weight of 63,540 Da and some typical polysaccharide absorption peaks in Fourier transform infrared spectrum. Monosaccharide components of the EPS contained rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose in a molar ratio of 0.2074:0.0454:0.0262:0.0446:1.7942:1.2086:0.4578. Pseudo plastic properties were also observed for the EPS through the rheological measurement. The EPS was further characterized for its behavior to cause membrane flux decline. The results showed that both flux declines for polyvinylidenefluoride (PVDF) and polypropylene membranes became more severe as EPS feed concentration increased. A higher irreversible fouling for the PVDF membrane suggested that the EPS had the larger fouling potential to this microfiltration membrane.

  10. Metagenomes reveal microbial structures, functional potentials, and biofouling-related genes in a membrane bioreactor.

    Science.gov (United States)

    Ma, Jinxing; Wang, Zhiwei; Li, Huan; Park, Hee-Deung; Wu, Zhichao

    2016-06-01

    Metagenomic sequencing was used to investigate the microbial structures, functional potentials, and biofouling-related genes in a membrane bioreactor (MBR). The results showed that the microbial community in the MBR was highly diverse. Notably, function analysis of the dominant genera indicated that common genes from different phylotypes were identified for important functional potentials with the observation of variation of abundances of genes in a certain taxon (e.g., Dechloromonas). Despite maintaining similar metabolic functional potentials with a parallel full-scale conventional activated sludge (CAS) system due to treating the identical wastewater, the MBR had more abundant nitrification-related bacteria and coding genes of ammonia monooxygenase, which could well explain its excellent ammonia removal in the low-temperature period. Furthermore, according to quantification of the genes involved in exopolysaccharide and extracellular polymeric substance (EPS) protein metabolism, the MBR did not show a much different potential in producing EPS compared to the CAS system, and bacteria from the membrane biofilm had lower abundances of genes associated with EPS biosynthesis and transport compared to the activated sludge in the MBR.

  11. Membrane bioreactor wastewater treatment plants reveal diverse yeast and protist communities of potential significance in biofouling.

    Science.gov (United States)

    Liébana, Raquel; Arregui, Lucía; Belda, Ignacio; Gamella, Luis; Santos, Antonio; Marquina, Domingo; Serrano, Susana

    2015-01-01

    The yeast community was studied in a municipal full-scale membrane bioreactor wastewater treatment plant (MBR-WWTP). The unexpectedly high diversity of yeasts indicated that the activated sludge formed a suitable environment for them to proliferate, with cellular concentrations of 2.2 ± 0.8 × 10(3) CFU ml(-1). Sixteen species of seven genera were present in the biological reactor, with Ascomycetes being the most prevalent group (93%). Most isolates were able to grow in a synthetic wastewater medium, adhere to polyethylene surfaces, and develop biofilms of variable complexity. The relationship between yeast populations and the protists in the MBR-WWTP was also studied, revealing that some protist species preyed on and ingested yeasts. These results suggest that yeast populations may play a role in the food web of a WWTP and, to some extent, contribute to membrane biofouling in MBR systems.

  12. Superhydrophobic PVDF and PVDF-HFP nanofibrous mats with antibacterial and anti-biofouling properties

    Energy Technology Data Exchange (ETDEWEB)

    Spasova, M.; Manolova, N. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria); Markova, N. [Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 26, BG-1113 Sofia (Bulgaria); Rashkov, I., E-mail: rashkov@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria)

    2016-02-15

    Graphical abstract: - Highlights: • New PVDF and PVDF-HFP nanofibers decorated with ZnO nanoparticles and a model drug. • The nanofibrous materials were fabricated by one-pot electrospinning. • The obtained materials are superhybrophobic and possess antibacterial properties. - Abstract: Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug – 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.

  13. Influence of elastomeric seal plate surface chemistry on interface integrity in biofouling-prone systems: Evaluation of a hydrophobic "easy-release" silicone-epoxy coating for maintaining water seal integrity of a sliding neoprene/steel interface

    Science.gov (United States)

    Andolina, Vincent L.

    The scientific hypothesis of this work is that modulation of the properties of hard materials to exhibit abrasion-reducing and low-energy surfaces will extend the functional lifetimes of elastomeric seals pressed against them in abrasive underwater systems. The initial motivation of this work was to correct a problem noted in the leaking of seals at major hydropower generating facilities subject to fouling by abrasive zebra mussel shells and extensive corrosion. Similar biofouling-influenced problems can develop at seals in medical devices and appliances from regulators in anesthetic machines and SCUBA diving oxygen supply units to autoclave door seals, injection syringe gaskets, medical pumps, drug delivery components, and feeding devices, as well as in food handling equipment like pasteurizers and transfer lines. Maritime and many other heavy industrial seal interfaces could also benefit from this coating system. Little prior work has been done to elucidate the relationship of seal plate surface properties to the friction and wear of elastomeric seals during sliding contacts of these articulating materials, or to examine the secondary influence of mineralized debris within the contacting interfaces. This investigation utilized the seal materials relevant to the hydropower application---neoprene elastomer against carbon steel---with and without the application of a silicone-epoxy coating (WearlonRTM 2020.98) selected for its wear-resistance, hydrophobicity, and "easy-release" capabilities against biological fouling debris present in actual field use. Analytical techniques applied to these materials before and after wear-producing processes included comprehensive Contact Angle measurements for Critical Surface Tension (CA-CST) determination, Scanning Electron Microscopic inspections, together with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and X-Ray Fluorescence (XRF) measurements for determination of surface texture and inorganic composition, Multiple

  14. Metabarcoding improves detection of eukaryotes from early biofouling communities: implications for pest monitoring and pathway management.

    Science.gov (United States)

    Zaiko, Anastasija; Schimanski, Kate; Pochon, Xavier; Hopkins, Grant A; Goldstien, Sharyn; Floerl, Oliver; Wood, Susanna A

    2016-07-01

    In this experimental study the patterns in early marine biofouling communities and possible implications for surveillance and environmental management were explored using metabarcoding, viz. 18S ribosomal RNA gene barcoding in combination with high-throughput sequencing. The community structure of eukaryotic assemblages and the patterns of initial succession were assessed from settlement plates deployed in a busy port for one, five and 15 days. The metabarcoding results were verified with traditional morphological identification of taxa from selected experimental plates. Metabarcoding analysis identified > 400 taxa at a comparatively low taxonomic level and morphological analysis resulted in the detection of 25 taxa at varying levels of resolution. Despite the differences in resolution, data from both methods were consistent at high taxonomic levels and similar patterns in community shifts were observed. A high percentage of sequences belonging to genera known to contain non-indigenous species (NIS) were detected after exposure for only one day.

  15. Biofouling behavior and performance of forward osmosis membranes with bioinspired surface modification in osmotic membrane bioreactor.

    Science.gov (United States)

    Li, Fang; Cheng, Qianxun; Tian, Qing; Yang, Bo; Chen, Qianyuan

    2016-07-01

    Forward osmosis (FO) has received considerable interest for water and energy related applications in recent years. Biofouling behavior and performance of cellulose triacetate (CTA) forward osmosis membranes with bioinspired surface modification via polydopamine (PD) coating and poly (ethylene glycol) (PEG) grafting (PD-g-PEG) in a submerged osmotic membrane bioreactor (OMBR) were investigated in this work. The modified membranes exhibited lower flux decline than the pristine one in OMBR, confirming that the bioinspired surface modification improved the antifouling ability of the CTA FO membrane. The result showed that the decline of membrane flux related to the increase of the salinity and MLSS concentration of the mixed liquid. It was concluded that the antifouling ability of modified membranes ascribed to the change of surface morphology in addition to the improvement of membrane hydrophilicity. The bioinspired surface modifications might improve the anti-adhesion for the biopolymers and biocake. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Aquatic biofouling prevention by electrically charged nanocomposite polymer thin film membranes.

    Science.gov (United States)

    de Lannoy, Charles-François; Jassby, David; Gloe, Katie; Gordon, Alexander D; Wiesner, Mark R

    2013-03-19

    Electrically conductive polymer-nanocomposite (ECPNC) tight nanofiltration (NF) thin film membranes were demonstrated to have biofilm-preventing capabilities under extreme bacteria and organic material loadings. A simple route to the creation and application of these polyamide-carbon nanotube thin films is also reported. These thin films were characterized with SEM and TEM as well as FTIR to demonstrate that the carbon nanotubes are embedded within the polyamide and form ester bonds with trimesoyl chloride, one of the monomers of polyamide. These polymer nanocomposite thin film materials boast high electrical conductivity (∼400 S/m), good NaCl rejection (>95%), and high water permeability. To demonstrate these membranes' biofouling capabilities, we designed a cross-flow water filtration vessel with insulated electrical leads connecting the ECPNC membranes to an arbitrary waveform generator. In all experiments, conducted in highly bacterially contaminated LB media, flux tests were run until fluxes decreased by 45 ± 3% over initial flux. Biofilm-induced, nonreversible flux decline was observed in all control experiments and a cross-flow rinse with the feed solution failed to induce flux recovery. In contrast, flux decrease for the ECPNC membranes with an electric potential applied to their surface was only caused by deposition of bacteria rather than bacterial attachment, and flux was fully recoverable following a short rinse with the feed solution and no added cleaning agents. The prevention of biofilm formation on the ECPNC membranes was a long-term effect, did not decrease with use, and was highly reproducible.

  17. Biofouling leads to reduced shell growth and flesh weight in the cultured mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Sievers, Michael; Fitridge, Isla; Dempster, Tim; Keough, Michael J

    2013-01-01

    Competitive interactions between cultured mussels and fouling organisms may result in growth and weight reductions in mussels, and compromised aquaculture productivity. Mussel ropes were inoculated with Ciona intestinalis, Ectopleura crocea or Styela clava, and growth parameters of fouled and unfouled Mytilus galloprovincialis were compared after two months. Small mussels (≈ 50 mm) fouled by C. intestinalis and E. crocea were 4.0 and 3.2% shorter in shell length and had 21 and 13% reduced flesh weight, respectively, compared to the controls. Large mussels (≈ 68 mm) fouled by S. clava, C. intestinalis and E. crocea were 4.4, 3.9 and 2.1% shorter than control mussels, respectively, but flesh weights were not significantly reduced. A series of competitive feeding experiments indicated that S. clava and C. intestinalis did not reduce mussels' food consumption, but that E. crocea, through interference competition, did. Fouling by these species at the densities used here reduced mussel growth and flesh weight, likely resulting in economic losses for the industry, and requires consideration when developing biofouling mitigation strategies.

  18. Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

    International Nuclear Information System (INIS)

    Rajabi, Hamid; Ghaemi, Negin; Madaeni, Sayed S.; Daraei, Parisa; Khadivi, Mohammad Ali; Falsafi, Monir

    2014-01-01

    Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling

  19. Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

    Energy Technology Data Exchange (ETDEWEB)

    Rajabi, Hamid [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Department of Civil Engineering, Razi University, 67149 Kermanshah (Iran, Islamic Republic of); Ghaemi, Negin, E-mail: negin_ghaemi@kut.ac.ir [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Madaeni, Sayed S. [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Daraei, Parisa [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Khadivi, Mohammad Ali [Friedrich-Alexander University, Erlangen-Nuremberg, Egerland Strasse 3, D-91058 Erlangen (Germany); Falsafi, Monir [Department of Chemistry, Faculty of Science, Razi University, 67149 Kermanshah (Iran, Islamic Republic of)

    2014-09-15

    Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling.

  20. Comparison of glassy carbon and boron doped diamond electrodes: Resistance to biofouling

    Energy Technology Data Exchange (ETDEWEB)

    Trouillon, Raphael, E-mail: raphael.trouillon06@imperial.ac.u [Department of Bioengineering, Imperial College London, Royal School of Mines Building, London SW7 2AZ (United Kingdom); O' Hare, Danny [Department of Bioengineering, Imperial College London, Royal School of Mines Building, London SW7 2AZ (United Kingdom)

    2010-09-01

    Carbon based electrodes are widely used for in vivo and in vitro electrochemical studies. In particular, monoamine neurochemistry has been investigated using carbon microfibre electrodes. Similarly, glassy carbon (GC) is the preferred material for many biochemical applications, such as electrochemical detection in chromatography. More recently, boron doped diamond (BDD) has been utilized for biosensing, as its carbon sp{sup 3} structure is expected to provide better resistance to analyte fouling. However, the main factor limiting the use of electrochemical sensors for biological studies is the effect of the biological matrix. Indeed, in vivo or in situ measurements expose the sensor to a complex matrix of proteins, which adsorb on the sensing surface and interfere with the electrochemical measurements. Here, we compare the performance of three carbon based electrodes: GC, GC with low surface oxides and BDD. The redox species ruthenium(III) hexaammine (outer-sphere), ferrocyanide (surface sensitive) and the biologically significant dopamine have been investigated in protein and blood-mimicking matrices. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to examine the effect of spectator molecules and reaction products on electrode mechanisms. Our results show that BDD generally exhibits the best performance for most conditions and reactions and should therefore be preferred for measurements in biologically fouling environments. Furthermore, surface oxides seem also to improve resistance of the GC electrode to biofouling.

  1. Comparison of glassy carbon and boron doped diamond electrodes: Resistance to biofouling

    International Nuclear Information System (INIS)

    Trouillon, Raphael; O'Hare, Danny

    2010-01-01

    Carbon based electrodes are widely used for in vivo and in vitro electrochemical studies. In particular, monoamine neurochemistry has been investigated using carbon microfibre electrodes. Similarly, glassy carbon (GC) is the preferred material for many biochemical applications, such as electrochemical detection in chromatography. More recently, boron doped diamond (BDD) has been utilized for biosensing, as its carbon sp 3 structure is expected to provide better resistance to analyte fouling. However, the main factor limiting the use of electrochemical sensors for biological studies is the effect of the biological matrix. Indeed, in vivo or in situ measurements expose the sensor to a complex matrix of proteins, which adsorb on the sensing surface and interfere with the electrochemical measurements. Here, we compare the performance of three carbon based electrodes: GC, GC with low surface oxides and BDD. The redox species ruthenium(III) hexaammine (outer-sphere), ferrocyanide (surface sensitive) and the biologically significant dopamine have been investigated in protein and blood-mimicking matrices. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to examine the effect of spectator molecules and reaction products on electrode mechanisms. Our results show that BDD generally exhibits the best performance for most conditions and reactions and should therefore be preferred for measurements in biologically fouling environments. Furthermore, surface oxides seem also to improve resistance of the GC electrode to biofouling.

  2. Acetylcholinesterase in Biofouling Species: Characterization and Mode of Action of Cyanobacteria-Derived Antifouling Agents.

    Science.gov (United States)

    Almeida, Joana R; Freitas, Micaela; Cruz, Susana; Leão, Pedro N; Vasconcelos, Vitor; Cunha, Isabel

    2015-07-24

    Effective and ecofriendly antifouling (AF) compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE) activity as an effect and/or mode of action of promising AF compounds, since AChE inhibitors were found to inhibit invertebrate larval settlement. To pursue this objective, in vitro quantification of AChE activity under the effect of several cyanobacterial strain extracts as potential AF agents was performed along with in vivo AF (anti-settlement) screening tests. Pre-characterization of different cholinesterases (ChEs) forms present in selected tissues of important biofouling species was performed to confirm the predominance of AChE, and an in vitro AF test using pure AChE activity was developed. Eighteen cyanobacteria strains were tested as source of potential AF and AChE inhibitor agents. Results showed effectiveness in selecting promising eco-friendly AF agents, allowing the understanding of the AF biochemical mode of action induced by different compounds. This study also highlights the potential of cyanobacteria as source of AF agents towards invertebrate macrofouling species.

  3. Acetylcholinesterase in Biofouling Species: Characterization and Mode of Action of Cyanobacteria-Derived Antifouling Agents

    Directory of Open Access Journals (Sweden)

    Joana R. Almeida

    2015-07-01

    Full Text Available Effective and ecofriendly antifouling (AF compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE activity as an effect and/or mode of action of promising AF compounds, since AChE inhibitors were found to inhibit invertebrate larval settlement. To pursue this objective, in vitro quantification of AChE activity under the effect of several cyanobacterial strain extracts as potential AF agents was performed along with in vivo AF (anti-settlement screening tests. Pre-characterization of different cholinesterases (ChEs forms present in selected tissues of important biofouling species was performed to confirm the predominance of AChE, and an in vitro AF test using pure AChE activity was developed. Eighteen cyanobacteria strains were tested as source of potential AF and AChE inhibitor agents. Results showed effectiveness in selecting promising eco-friendly AF agents, allowing the understanding of the AF biochemical mode of action induced by different compounds. This study also highlights the potential of cyanobacteria as source of AF agents towards invertebrate macrofouling species.

  4. In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

    KAUST Repository

    Fortunato, Luca

    2017-01-13

    Membrane systems for water purification can be seriously hampered by biofouling. The use of optical coherence tomography (OCT) to investigate biofilms in membrane systems has recently increased due to the ability to do the characterization in-situ and non-destructively The OCT biofilm thickness map is presented for the first time as a tool to assess biofilm spatial distribution on a surface. The map allows the visualization and evaluation of the biofilm formation and growth in membrane filtration systems through the use of a false color scale. The biofilm development was monitored with OCT to evaluate the suitability of the proposed approach. A 3D time series analysis of biofilm development in a spacer filled channel representative of a spiral-wound membrane element was performed. The biofilm thickness map enables the time-resolved and spatial-resolved evaluation and visualization of the biofilm deposition pattern in-situ non-destructively.

  5. Thermal treatment as a method to control transfers of invasive biofouling species via vessel sea chests.

    Science.gov (United States)

    Piola, Richard F; Hopkins, Grant A

    2012-08-01

    This study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. In laboratory trials, three temperature regimes (37.5°C for 60 min, 40°C for 30min and 42.5°C for 20 min) were tested on a range of temperate taxa commonly found in sea chests. Field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. During laboratory trials, 100% mortality was achieved across all three treatments for the majority of taxa; the exceptions being the barnacle Elminius modestus and the oyster Crassostrea gigas. Temperature tolerance limits observed in the laboratory were successfully replicated under simulated sea chest conditions; however, a failure to achieve even heat distribution was an obstacle to achieving uniform mortality. This study provides guidance on the temperature/exposure parameters required for vessels plying temperate latitudes, and demonstrates that heated seawater has potential for controlling biofouling in vessel sea chests. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Marine bio-fouling of different alloys exposed to continuous flowing fresh seawater by electrochemical impedance spectroscopy

    Directory of Open Access Journals (Sweden)

    Khalid Al-Muhanna

    2016-07-01

    Full Text Available The petroleum industry and desalination plants suffer from marine bio-fouling problems that have a major role in the stimulation of the corrosion process. Thus, the aim of this study was to investigate the effect of the micro and the macro-organisms, on the corrosion behavior of different alloys used in Kuwait’s industries. The alloys used in this study were; sanicro 28, stainless steel 316L, Cu–Ni 70–30, and titanium. The electrochemical impedance spectroscopy was used in this study in order to determine the corrosion susceptibility of different alloys exposed to continuous fresh seawater. This was achieved by calculating the charge transfer resistance of the metal surface and the resistance of the solution. The total exposure time of the tests was about 180 days. The visual inspection of the tested samples, showed a bio-film formation on the surface of these samples. Also, it was observed that the stainless steel 316, sanicro 28, Cu–Ni 70–30, and titanium alloys exhibited good corrosion resistance.

  7. Geochemistry and microbiology of iron-related well-screen encrustation and aquifer biofouling in Suffolk County, Long Island, New York

    Science.gov (United States)

    Walter, D.A.

    1997-01-01

    Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of several production wells in Suffolk County, N.Y., and has forced the Suffolk County Water Authority to adopt a costly well-reconditioning and replacement program. The specific-capacity declines are the result of the precipitation of iron oxyhydroxides and the growth of iron bacteria on the well screens and in the pore spaces of the surrounding formation. Mineralogic and chemical analyses indicate that the inorganic part of the encrusting material consists primarily of amorphous ferric hydroxide (Fe(OH)3 ); minor components of the material include goethite (FeOOH), hematite (Fe2 O 3 ), and quartz (SiO 2 ). The weight percent of ferric hydroxide in the material ranged from 32.3 to 98.6 percent and averaged 64.3 percent. Equilibrium modeling indicated that during pumping the well waters were supersaturated with respect to goethite, hematite, magnetite, and quartz and were under-saturated with respect to ferric hydroxide. Theoretical Eh values computed for the ferrous/ferric-iron redox couple and the oxygen/water redox couple averaged 390 millivolts and 810 millivolts, respectively, indicating that the waters were in a state of redox disequilibrium. The disequilibrium condition arises from the mixing of ground water with a low dissolved-oxygen concentration with oxygenated ground water during operation of the well. The low pH of the ground water contributes to the disequilibrium condition by slowing the rate of iron oxidation after the introduction of oxygen. Chemical and mineralogical data indicate that most of the encrusting material in the wells was deposited while the wells were shut down, probably in response to the use of treated water of higher pH to keep pump turbines wet while the wells were not in operation; the increased pH of water in the static water column increases the rate of ferrous-iron oxidation and causes the well water to become increasingly

  8. Design, Fabrication, and In Vitro Testing of an Anti-biofouling Glaucoma Micro-shunt.

    Science.gov (United States)

    Harake, Ryan S; Ding, Yuzhe; Brown, J David; Pan, Tingrui

    2015-10-01

    Glaucoma, one of the leading causes of irreversible blindness, is a progressive neurodegenerative disease. Chronic elevated intraocular pressure (IOP), a prime risk factor for glaucoma, can be treated by aqueous shunts, implantable devices, which reduce IOP in glaucoma patients by providing alternative aqueous outflow pathways. Although initially effective at delaying glaucoma progression, contemporary aqueous shunts often lead to numerous complications and only 50% of implanted devices remain functional after 5 years. In this work, we introduce a novel micro-device which provides an innovative platform for IOP reduction in glaucoma patients. The device design features an array of parallel micro-channels to provide precision aqueous outflow resistance control. Additionally, the device's microfluidic channels are composed of a unique combination of polyethylene glycol materials in order to provide enhanced biocompatibility and resistance to problematic channel clogging from biofouling of aqueous proteins. The microfabrication process employed to produce the devices results in additional advantages such as enhanced device uniformity and increased manufacturing throughput. Surface characterization experimental results show the device's surfaces exhibit significantly less non-specific protein adsorption compared to traditional implant materials. Results of in vitro flow experiments verify the device's ability to provide aqueous resistance control, continuous long-term stability through 10-day protein flow testing, and safety from risk of infection due to bacterial ingression.

  9. Principles of biofouling protection in marine sponges: a model for the design of novel biomimetic and bio-inspired coatings in the marine environment?

    Science.gov (United States)

    Müller, Werner E G; Wang, Xiaohong; Proksch, Peter; Perry, Carole C; Osinga, Ronald; Gardères, Johan; Schröder, Heinz C

    2013-08-01

    The process of biofouling of marine structures and substrates, such as platforms or ship hulls, proceeds in multiple steps. Soon after the formation of an initial conditioning film, formed via the adsorption of organic particles to natural or man-made substrates, a population of different bacterial taxa associates under the formation of a biofilm. These microorganisms communicate through a complex quorum sensing network. Macro-foulers, e.g., barnacles, then settle and form a fouling layer on the marine surfaces, a process that globally has severe impacts both on the economy and on the environment. Since the ban of tributyltin, an efficient replacement of this antifouling compound by next-generation antifouling coatings that are environmentally more acceptable and also showing longer half-lives has not yet been developed. The sponges, as sessile filter-feeder animals, have evolved antifouling strategies to protect themselves against micro- and subsequent macro-biofouling processes. Experimental data are summarized and suggest that coating of the sponge surface with bio-silica contributes to the inhibition of the formation of a conditioning film. A direct adsorption of the surfaces by microorganisms can be impaired through poisoning the organisms with direct-acting secondary metabolites or toxic peptides. In addition, first, compounds from sponges have been identified that interfere with the anti-quorum sensing network. Sponge secondary metabolites acting selectively on diatom colonization have not yet been identified. Finally, it is outlined that direct-acting secondary metabolites inhibiting the growth of macro-fouling animals and those that poison the multidrug resistance pump are available. It is concluded that rational screening programs for inhibitors of the complex and dynamic problem of biofilm production, based on multidisciplinary studies and using sponges as a model, are required in the future.

  10. Interrupting a multi-species bioinvasion vector: the efficacy of in-water cleaning for removing biofouling on obsolete vessels.

    Science.gov (United States)

    Davidson, Ian C; McCann, Linda D; Sytsma, Mark D; Ruiz, Gregory M

    2008-09-01

    Vector management is the primary method for reducing and preventing nonindigenous species (NIS) invasions and their ecological and economic consequences. This study was the first to examine the efficacy of in-water scrubbing using a submersible cleaning and maintenance platform (SCAMP) to prevent invertebrate species transfers from a heavily fouled obsolete vessel. Initially, prior to treatment, 37 species were recorded in a biofouling matrix that reached 30cm depth in some locations. The bryozoan Conopeum chesapeakensis, and bivalves Mytilopsis leucophaeata and Ischadium recurvum, were dominant sessile species that created structure, supporting mobile biota that included crabs and the associated parasitic barnacle Loxothylacus panopae. Scrubbing had the effect of significantly reducing organism extent and the number of species per sample, but a substantial and diverse (30 species) residual fouling community remained across the entire vessel. Further assessments of management options are needed to prevent potentially damaging NIS transfers. Additional measures taken within an integrated vector management (IVM) strategy may further improve invasion prevention measures.

  11. Factors influencing the en route survivorship and post-voyage growth of a common ship biofouling organism, Bugula neritina.

    Science.gov (United States)

    Schimanski, Kate B; Piola, Richard F; Goldstien, Sharyn J; Floerl, Oliver; Grandison, Clare; Atalah, Javier; Hopkins, Grant A

    2016-09-01

    The likelihood that viable non-indigenous biofouling species will survive a voyage on a vessel is influenced by a range of factors, including the speed, duration, and route of the voyage and the amount of time the vessel spends in port. In this study, a land-based dynamic flow device was used to test the effect of recruit age, vessel speed and voyage duration on the survivorship and growth of the bryozoan Bugula neritina. In the experiment, one-week-old recruits had a higher likelihood (100%) of surviving voyages than older (one-month-old, 90%) or younger (one-day-old, 79%) recruits, but survival was not influenced by vessel speed (6 and 18 knots) or voyage duration (two and eight days). The results suggest that the non-indigenous species B. neritina can be effectively transferred at a range of ages but one-week-old recruits are more likely to survive the translocation process and survive in the recipient environment.

  12. Biofouling growth in cold estuarine waters and evaluation of some chitosan and copper anti-fouling paints.

    Science.gov (United States)

    Pelletier, Emilien; Bonnet, Claudie; Lemarchand, Karine

    2009-07-14

    Ecological concerns about antifouling paints containing non-green tin and copper compounds have highlighted the need for environmentally friendly alternatives. We report here a field test conducted in estuarine waters over two months designed to evaluate the efficiency of a number of active natural and man-made chemical ingredients added into a silicon-polyurethane marine paint. Early steps of biofouling in cold seawater of the St. Lawrence Estuary (Canada) were observed. Analyses, including dry biomass, flow cytometry and spectrofluorimetry, demonstrated a short-term antibacterial action of chitosan-based paints although no significant anti-algal action was observed. Cuprous oxide paints were efficient against bacteria and algae invasion in the first two weeks, especially those with added organic biocides such as isothiazolone and copper pyrithione. However, the overall dry biomass and chlorophyll a content were similar for all chitosan-and copper-based paints after 63 days. Microscopic observations revealed variation in the highly diverse benthic diatom population including species Navicula, Melosira, Cocconeis, Nitshzcia, Fragilaria and Amphora. Results suggest no real long-term efficiency for tested antifouling paints and highlight a particular need for green antifouling ingredients that are active under northern estuarine conditions.

  13. Biofouling Growth in Cold Estuarine Waters and Evaluation of Some Chitosan and Copper Anti-Fouling Paints

    Directory of Open Access Journals (Sweden)

    Karine Lemarchand

    2009-07-01

    Full Text Available Ecological concerns about antifouling paints containing non-green tin and copper compounds have highlighted the need for environmentally friendly alternatives. We report here a field test conducted in estuarine waters over two months designed to evaluate the efficiency of a number of active natural and man-made chemical ingredients added into a silicon-polyurethane marine paint. Early steps of biofouling in cold seawater of the St. Lawrence Estuary (Canada were observed. Analyses, including dry biomass, flow cytometry and spectrofluorimetry, demonstrated a short-term antibacterial action of chitosan-based paints although no significant anti-algal action was observed. Cuprous oxide paints were efficient against bacteria and algae invasion in the first two weeks, especially those with added organic biocides such as isothiazolone and copper pyrithione. However, the overall dry biomass and chlorophyll a content were similar for all chitosan- and copper-based paints after 63 days. Microscopic observations revealed variation in the highly diverse benthic diatom population including species Navicula, Melosira, Cocconeis, Nitshzcia, Fragilaria and Amphora. Results suggest no real long-term efficiency for tested antifouling paints and highlight a particular need for green antifouling ingredients that are active under northern estuarine conditions.

  14. Biofouling likely serves as a major mode of dispersal for the polychaete tubeworm Hydroides elegans as inferred from microsatellite loci.

    Science.gov (United States)

    Pettengill, J B; Wendt, D E; Schug, M D; Hadfield, M G

    2007-01-01

    The polychaete tubeworm Hydroides elegans (Haswell) is a biofouling species with relatively limited larval dispersal. Four highly polymorphic microsatellite loci were used to make inferences about the migration and global population structure of 137 individuals from seven sub-populations located in the Atlantic, Pacific, and Indian Oceans and in the Mediterranean Sea. The results of the genetic analyses suggest minimal population sub-structure (F(st) = 0.09). Estimates of pairwise F(st) and migration rates using the coalescent-based method of MIGRATE suggest that there is little genetic differentiation between certain populations. Variation in relatedness among pairs of populations is consistent with a suite of local and global factors. The most likely explanation for close genetic relatedness among certain populations over such vast distances is the regular and consistent transport of adults and larvae on the hulls and in the ballast water of ships, respectively.

  15. Effect of flow velocity, substrate concentration and hydraulic cleaning on biofouling of reverse osmosis feed channels

    KAUST Repository

    Radu, Andrea I.

    2012-04-01

    A two-dimensional mathematical model coupling fluid dynamics, salt and substrate transport and biofilm development in time was used to investigate the effects of cross-flow velocity and substrate availability on biofouling in reverse osmosis (RO)/nanofiltration (NF) feed channels. Simulations performed in channels with or without spacer filaments describe how higher liquid velocities lead to less overall biomass amount in the channel by increasing the shear stress. In all studied cases at constant feed flow rate, biomass accumulation in the channel reached a steady state. Replicate simulation runs prove that the stochastic biomass attachment model does not affect the stationary biomass level achieved and has only a slight influence on the dynamics of biomass accumulation. Biofilm removal strategies based on velocity variations are evaluated. Numerical results indicate that sudden velocity increase could lead to biomass sloughing, followed however by biomass re-growth when returning to initial operating conditions. Simulations show particularities of substrate availability in membrane devices used for water treatment, e.g., the accumulation of rejected substrates at the membrane surface due to concentration polarization. Interestingly, with an increased biofilm thickness, the overall substrate consumption rate dominates over accumulation due to substrate concentration polarization, eventually leading to decreased substrate concentrations in the biofilm compared to bulk liquid. © 2012 Elsevier B.V.

  16. Evaluation of pre-treatment technologies for phosphorous removal from drinking water to mitigate membrane biofouling

    Science.gov (United States)

    Frolova, M.; Tihomirova, K.; Mežule, L.; Rubulis, J.; Gruškeviča, K.; Juhna, T.

    2017-10-01

    Membranes are widely used for the treatment of various solutions. However, membrane fouling remains the limiting factor for their usage, setting biofouling as the most severe type of it. Therefore, the production of biologically stable water prior to membranes is important. Since lack of phosphorus may hinder the growth of microorganisms, the aim of this research is to evaluate the effect of microbially available phosphorus (MAP) removal via affordable water pre-treatment methods (adsorption, biofiltration, electrocoagulation) on bacterial growth. Four cylindrical reactors were installed at an artificially recharged groundwater station. Further temperature influence and carbon limitation were tested for biofiltration technology. The amount of MAP and total cell count was measured by flow cytometry. The results showed that at lower temperatures electrocoagulation performed the best, resulting in complete MAP removal (detection limit 6.27x10-3μg P l-1). Sorbent demonstrated MAP removal of 70-90%. Biomass did not have any noteworthy results at +8°C, however, at +19°C MAP removal of around 80% was achieved. Main conclusions obtained within this study are: (i) tested technologies effectively eliminate MAP levels; (ii) temperature has a significant effect on MAP removal in a bioreactor, (iii) multi-barrier approach might be necessary for better P limitation that might prolong operating time of a membrane.

  17. Effectiveness of Devices to Monitor Biofouling and Metals Deposition on Plumbing Materials Exposed to a Full-Scale Drinking Water Distribution System.

    Science.gov (United States)

    Ginige, Maneesha P; Garbin, Scott; Wylie, Jason; Krishna, K C Bal

    2017-01-01

    A Modified Robbins Device (MRD) was installed in a full-scale water distribution system to investigate biofouling and metal depositions on concrete, high-density polyethylene (HDPE) and stainless steel surfaces. Bulk water monitoring and a KIWA monitor (with glass media) were used to offline monitor biofilm development on pipe wall surfaces. Results indicated that adenosine triphosphate (ATP) and metal concentrations on coupons increased with time. However, bacterial diversities decreased. There was a positive correlation between increase of ATP and metal deposition on pipe surfaces of stainless steel and HDPE and no correlation was observed on concrete and glass surfaces. The shared bacterial diversity between bulk water and MRD was less than 20% and the diversity shared between the MRD and KIWA monitor was only 10%. The bacterial diversity on biofilm of plumbing material of MRD however, did not show a significant difference suggesting a lack of influence from plumbing material during early stage of biofilm development.

  18. Effectiveness of Devices to Monitor Biofouling and Metals Deposition on Plumbing Materials Exposed to a Full-Scale Drinking Water Distribution System.

    Directory of Open Access Journals (Sweden)

    Maneesha P Ginige

    Full Text Available A Modified Robbins Device (MRD was installed in a full-scale water distribution system to investigate biofouling and metal depositions on concrete, high-density polyethylene (HDPE and stainless steel surfaces. Bulk water monitoring and a KIWA monitor (with glass media were used to offline monitor biofilm development on pipe wall surfaces. Results indicated that adenosine triphosphate (ATP and metal concentrations on coupons increased with time. However, bacterial diversities decreased. There was a positive correlation between increase of ATP and metal deposition on pipe surfaces of stainless steel and HDPE and no correlation was observed on concrete and glass surfaces. The shared bacterial diversity between bulk water and MRD was less than 20% and the diversity shared between the MRD and KIWA monitor was only 10%. The bacterial diversity on biofilm of plumbing material of MRD however, did not show a significant difference suggesting a lack of influence from plumbing material during early stage of biofilm development.

  19. Enhanced biofouling resistance of polyethersulfone membrane surface modified with capsaicin derivative and itaconic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Gao, Xueli, E-mail: gxl_ouc@126.com [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Wang, Qun; Sun, Haijing; Wang, Xiaojuan [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Gao, Congjie, E-mail: gaocjie@ouc.edu.cn [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China)

    2015-11-30

    Graphical abstract: - Highlights: • PES membrane was modified with a capsaicin derivative. • UV-assisted graft polymerization was carried out on membrane surface. • The capsaicin derivative modified membrane shows better antibiofouling property. - Abstract: The culprit of biofouling is the reproduction of viable microorganisms on the membrane surface. Recently, functionalization of membrane surface with natural antibacterial agents has drawn great attention. This work presents the fabrication of antibiofouling polyethersulfone (PES) ultrafiltration (UF) membranes by UV-assisted photo grafting of capsaicin derivative (N-(4-hydroxy-3-methoxy-benzyl)-acrylamide, HMBA) and itaconic acid (IA) on the surface of PES membrane. Results of FTIR-ATR, water static contact angle (WSCA) and atomic force microscopy (AFM) analysis confirmed the successful grafting of HMBA and IA on the membrane surface. We investigated the antifouling and antibacterial properties of these membranes using BSA and Escherichia coli as the test model, respectively. During a 150-min test, the modified membranes show much lower flux decline (42.7% for PES-g-1H0I, 22.2% for PES-g-1H1I and 7.7% for PES-g-1H5I) when compared with the pristine membrane (flux declined by 77%). The modified membranes exhibit excellent antibacterial activity (nearly 100%) when UV irradiation time was 6 min. The morphological study suggested that the E. coli on the pristine membrane showed a regular and smooth surface while that on the modified membrane was disrupted, which validated the antibacterial activity of the modified membranes.

  20. Enhanced biofouling resistance of polyethersulfone membrane surface modified with capsaicin derivative and itaconic acid

    International Nuclear Information System (INIS)

    Wang, Jian; Gao, Xueli; Wang, Qun; Sun, Haijing; Wang, Xiaojuan; Gao, Congjie

    2015-01-01

    Graphical abstract: - Highlights: • PES membrane was modified with a capsaicin derivative. • UV-assisted graft polymerization was carried out on membrane surface. • The capsaicin derivative modified membrane shows better antibiofouling property. - Abstract: The culprit of biofouling is the reproduction of viable microorganisms on the membrane surface. Recently, functionalization of membrane surface with natural antibacterial agents has drawn great attention. This work presents the fabrication of antibiofouling polyethersulfone (PES) ultrafiltration (UF) membranes by UV-assisted photo grafting of capsaicin derivative (N-(4-hydroxy-3-methoxy-benzyl)-acrylamide, HMBA) and itaconic acid (IA) on the surface of PES membrane. Results of FTIR-ATR, water static contact angle (WSCA) and atomic force microscopy (AFM) analysis confirmed the successful grafting of HMBA and IA on the membrane surface. We investigated the antifouling and antibacterial properties of these membranes using BSA and Escherichia coli as the test model, respectively. During a 150-min test, the modified membranes show much lower flux decline (42.7% for PES-g-1H0I, 22.2% for PES-g-1H1I and 7.7% for PES-g-1H5I) when compared with the pristine membrane (flux declined by 77%). The modified membranes exhibit excellent antibacterial activity (nearly 100%) when UV irradiation time was 6 min. The morphological study suggested that the E. coli on the pristine membrane showed a regular and smooth surface while that on the modified membrane was disrupted, which validated the antibacterial activity of the modified membranes.

  1. Surface Charges and Shell Crosslinks Each Play Significant Roles in Mediating Degradation, Biofouling, Cytotoxicity and Immunotoxicity for Polyphosphoester-based Nanoparticles

    Science.gov (United States)

    Elsabahy, Mahmoud; Zhang, Shiyi; Zhang, Fuwu; Deng, Zhou J.; Lim, Young H.; Wang, Hai; Parsamian, Perouza; Hammond, Paula T.; Wooley, Karen L.

    2013-11-01

    The construction of nanostructures from biodegradable precursors and shell/core crosslinking have been pursued as strategies to solve the problems of toxicity and limited stability, respectively. Polyphosphoester (PPE)-based micelles and crosslinked nanoparticles with non-ionic, anionic, cationic, and zwitterionic surface characteristics for potential packaging and delivery of therapeutic and diagnostic agents, were constructed using a quick and efficient synthetic strategy, and importantly, demonstrated remarkable differences in terms of cytotoxicity, immunotoxicity, and biofouling properties, as a function of their surface characteristics and also with dependence on crosslinking throughout the shell layers. For instance, crosslinking of zwitterionic micelles significantly reduced the immunotoxicity, as evidenced from the absence of secretions of any of the 23 measured cytokines from RAW 264.7 mouse macrophages treated with the nanoparticles. The micelles and their crosslinked analogs demonstrated lower cytotoxicity than several commercially-available vehicles, and their degradation products were not cytotoxic to cells at the range of the tested concentrations. PPE-nanoparticles are expected to have broad implications in clinical nanomedicine as alternative vehicles to those involved in several of the currently available medications.

  2. Organic carbon movement through two SWRO facilities from source water to pretreatment to product with relevance to membrane biofouling

    KAUST Repository

    Alshahri, Abdullah Hassan Mohammed

    2016-12-29

    The presence of algae, bacteria, various fractions of natural organic matter (NOM), and transparent exopolymer particles (TEP) in the raw water, after each pretreatment process and in the permeate and concentrate streams, were measured at two SWRO plants to assess biofouling potential. It was found that the most significant process controlling the concentration of algae, bacteria, and the biopolymer and humic substances was the intake type with the subsurface intake discharge showing significant reductions. The mixed media filtration process was marginally useful in removing some TOC and NOM, but had little effect on TEP removal. Some bacterial regrowth may be occurring in the cartridge filters, but the evidence is inconsistent. Significant quantities of the biopolymer and humic substance concentrations were found to be retained in the membranes, but the concentrations were significantly greater in the facility using an open-ocean intake. Bacteria and TEP were found in the permeate stream, which may document bacterial regrowth and TEP production downstream of the membrane process. Measurements of the organic carbon passage through SWRO facilities can be successfully used to evaluate pretreatment process effectiveness and to make SWRO plant operational improvements.

  3. The anti-biofouling behavior of high voltage pulse electric field (HPEF) mediated by carbon fiber composite coating in seawater.

    Science.gov (United States)

    Feng, Tiantian; Wu, Jinyi; Chai, Ke; Yang, Pengpeng

    2018-04-25

    One of the most important research areas in the marine industry is to investigate new and effective anti-biofouling technologies. In this study, high voltage pulse electric field (HPEF) mediated by carbon fiber (CF) composite coating was utilized to prevent the fouling of bacteria, microalgae and barnacle larvae in seawater. The plate count, 2, 3, 5-triphenyl-tetrazolium chloride (TTC) reduction assay and neutral red (NR) staining and larval motility detection showed that the inactivation rates were at the highest levels, which reached 99.1%, 99.9%, 99.7%, 98.7% and 85% respectively for Pseudomonas sp., Vibrio sp., iron bacteria, Navicula sp. and the second stage nauplii of Balanus reticulatus, under the HPEF with 19 kV pulse amplitude, 23.15 kHz frequency and 0.5 duty cycle. The field-emission scanning electron microscopy (FE-SEM) of Navicula sp. revealed that the HPEF brought about the cell lysis and the cell organic matter release on the coating, which could be the mechanism of the inactivation by the HPEF. Additionally, the FE-SEM and Raman spectroscopy indicated that the HPEF hardly damaged the coating. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Biofouling patterns in spacer filled channels: High resolution imaging for characterization of heterogeneous biofilms

    KAUST Repository

    Staal, Marc

    2017-08-15

    Biofilms develop in heterogeneous patterns at a µm scale up to a cm scale, and patterns become more pronounced when biofilms develop under complex hydrodynamic flow regimes. Spatially heterogeneous biofilms are especially known in spiral wound reverse osmosis (RO) and nanofiltration (NF) membrane filtration systems used for desalination and wastewater reuse to produce high quality (drinking) water. These spiral wound membrane modules contain mesh-like spacer structures used to create an intermembrane space and improve water mixing. Spacers create inhomogeneous water flow patterns resulting in zones favouring biofilm growth, possibly leading to biofouling thus hampering water production. Oxygen sensing planar optodes were used to visualize variations in oxygen decrease rates (ODR). ODR is an indication of biofilm activity. In this study, ODR images of multiple repetitive spacer areas in a membrane fouling simulator were averaged to produce high resolution, low noise ODR images. Averaging 40 individual spacer areas improved the ODR distribution image significantly and allowed comparison of biofilm patterning over a spacer structure at different positions in an RO filter. This method clearly showed that most active biofilm accumulated on and in direct vicinity of the spacer. The averaging method was also used to calculate the deviation of ODR patterning from individual spacer areas to the average ODR pattern, proposing a new approach to determine biofilm spatial heterogeneity. This study showed that the averaging method can be applied and that the improved, averaged ODR images can be used as an analytical, in-situ, non-destructive method to assess and quantify the effect of membrane installation operational parameters or different spacer geometries on biofilm development in spiral wound membrane systems characterized by complex hydrodynamic conditions.

  5. Early Detection of Biofouling on Water Purification Membranes by Ambient Ionization Mass Spectrometry Imaging.

    Science.gov (United States)

    Jakka Ravindran, Swathy; Kumar, Ramesh; Srimany, Amitava; Philip, Ligy; Pradeep, Thalappil

    2018-01-02

    By direct analysis of water purification membranes using ambient ionization mass spectrometry, an attempt has been made to understand the molecular signatures of bacterial fouling. Membrane based purification methods are used extensively in water treatment, and a major challenge for them is biofouling. The buildup of microbes and their extracellular polymeric matrix clog the purification membranes and reduce their efficiency. To understand the early stages of bacterial fouling on water purification membranes, we have used desorption electrospray ionization mass spectrometry (DESI MS), where ion formation occurs in ambient conditions and the ionization event is surface sensitive. Biosurfactants at the air-water interface generated by microorganisms as a result of quorum sensing, influence the water-membrane interface and are important for the bacterial attachment. We show that these biosurfactants produced by bacteria can be indicator molecular species signifying initiation of biofilms on membrane surfaces, demonstrated by specific DESI MS signatures. In Pseudomonas aeruginosa, one of the best studied models for biofilm formation, this process is mediated by rhamnolipids forewarning bacterial fouling. Species dependent variation of such molecules can be used for the precise identification of the microorganisms, as revealed by studies on P. aeroginosa (ATCC 25619). The production of biosurfactants is tightly regulated at the transcriptional level by the quorum-sensing (QS) response. Thus, secretion of these extracellular molecules across the membrane surface allows rapid screening of the biofilm community. We show that, the ambient ionization mass spectrometry can detect certain toxic heavy metals present in water, using surfactant-metal complexes as analytes. We believe that such studies conducted on membranes in various input water streams will help design suitable membrane processes specific to the input streams.

  6. Effects of prolonged entanglement in discarded fishing gear with substantive biofouling on the health and behavior of an adult shortfin mako shark, Isurus oxyrinchus.

    Science.gov (United States)

    Wegner, Nicholas C; Cartamil, Daniel P

    2012-02-01

    A mature male shortfin mako, Isurus oxyrinchus, was captured with a three-strand twisted natural fiber rope wrapped around the body causing deep abrasions, scoliosis of the back, and undernourishment. Fifty-two pelagic peduculate barnacles from four species were found fouling on the rope. Assuming larval settlement occurred following entanglement, barnacle growth-rate data suggest the rope had been around the shark for at least 150 days. However, the onset of severe scoliosis (likely linked to the increased constriction of the rope with growth and the added drag induced by biofouling) indicates that this rope may have been in place much longer. Following removal of the rope, a pop-up satellite archival tag was attached to the shark to assess post-release health. The resulting 54 days of tag deployment data show that despite its injuries, the shark survived, and following an initial stress period, exhibited movement patterns characteristic of healthy makos. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Corrosion and biofouling on the non-heat-exchanger surfaces of an ocean thermal energy conversion power plant: a survey

    Energy Technology Data Exchange (ETDEWEB)

    Castelli, V.J. (ed.)

    1979-05-01

    Of the many foreseeable problems confronting economical ocean thermal energy conversion operation, two major items are the deterioration of the structural and functional components, which prevents efficient operation, and the biofouling of the surfaces, which adds excess weight to the floating ocean platform. The techniques required for effective long-term control of deterioration and corrosion have been investigated actively for many years, and successful solutions for most situations have been developed. For the most part, these solutions can be directly transferred to the ocean thermal energy conversion plant. The majority of problems in these areas are expected to be associated with scale-up and will require some advanced development due to the immensity of the ocean thermal energy conversion platform. Current antifouling control systems are not effective for long-term fouling prevention. Commercially available antifouling coatings are limited to a 3-year service life in temperate waters, and even shorter in tropical waters. However, underwater cleaning techniques and some fouling-control systems presently being used by conventional power plants may find utility on an ocean thermal energy conversion plant. In addition, some recent major advances in long-term antifouling coatings sponsored by the Navy may be applicable to ocean thermal energy conversion. 132 references.

  8. Automated DNA extraction platforms offer solutions to challenges of assessing microbial biofouling in oil production facilities.

    Science.gov (United States)

    Oldham, Athenia L; Drilling, Heather S; Stamps, Blake W; Stevenson, Bradley S; Duncan, Kathleen E

    2012-11-20

    The analysis of microbial assemblages in industrial, marine, and medical systems can inform decisions regarding quality control or mitigation. Modern molecular approaches to detect, characterize, and quantify microorganisms provide rapid and thorough measures unbiased by the need for cultivation. The requirement of timely extraction of high quality nucleic acids for molecular analysis is faced with specific challenges when used to study the influence of microorganisms on oil production. Production facilities are often ill equipped for nucleic acid extraction techniques, making the preservation and transportation of samples off-site a priority. As a potential solution, the possibility of extracting nucleic acids on-site using automated platforms was tested. The performance of two such platforms, the Fujifilm QuickGene-Mini80™ and Promega Maxwell®16 was compared to a widely used manual extraction kit, MOBIO PowerBiofilm™ DNA Isolation Kit, in terms of ease of operation, DNA quality, and microbial community composition. Three pipeline biofilm samples were chosen for these comparisons; two contained crude oil and corrosion products and the third transported seawater. Overall, the two more automated extraction platforms produced higher DNA yields than the manual approach. DNA quality was evaluated for amplification by quantitative PCR (qPCR) and end-point PCR to generate 454 pyrosequencing libraries for 16S rRNA microbial community analysis. Microbial community structure, as assessed by DGGE analysis and pyrosequencing, was comparable among the three extraction methods. Therefore, the use of automated extraction platforms should enhance the feasibility of rapidly evaluating microbial biofouling at remote locations or those with limited resources.

  9. Prevention of Biofouling in Hydrocarbons by Antimicrobial Vessel and Pipeline Coating for Cost Savings and an Increase in Safety and Reliability

    Directory of Open Access Journals (Sweden)

    Maximilian Lackner

    2013-04-01

    Full Text Available Hydrocarbons are prone to bacterial and fungal contamination. Bacteria and fungi live and proliferate in water droplets within the fuels and on surfaces surrounding them. This can cause corrosion in oil exploration and production, clogging of fuel lines in aviation and higher emissions in diesel combustion engines to state few examples. State-of-the-art is the addition of biocides to fuels, which is associated with several disadvantages like costs and environmental burden. A novel technology to prevent biofouling in hydrocarbons is presented here. By applying an anti-microbial coating to the surfaces of hydrocarbon processing units, pipelines, and fuel containers, microbial growth can effectively be reduced. The coating can be a paint or varnish, for instance, epoxy resin as already used in aircraft fuel tanks to today. It contains transition metal oxides, thus an acidic surface is produced. This acidic surface was shown to eliminate up to 109 colony forming units per milliliter (CFU.ml-1 of bacteria of the species of agrobacterium tumefaciens and others in diesel, kerosene, and biodiesel, where other anti-microbial coatings based on silver did not perform. The technology has the potential to bring huge cost savings to the oil and gas industry, alongside an increase in safety and equipment reliability.

  10. Biofouling potential and material reactivity in a simulated water distribution network supplied with stormwater recycled via managed aquifer recharge.

    Science.gov (United States)

    Gonzalez, Dennis; Tjandraatmadja, Grace; Barry, Karen; Vanderzalm, Joanne; Kaksonen, Anna H; Dillon, Peter; Puzon, Geoff J; Sidhu, Jatinder; Wylie, Jason; Goodman, Nigel; Low, Jason

    2016-11-15

    The injection of stormwater into aquifers for storage and recovery during high water demand periods is a promising technology for augmenting conventional water reserves. Limited information exists regarding the potential impact of aquifer treated stormwater in distribution system infrastructure. This study describes a one year pilot distribution pipe network trial to determine the biofouling potential for cement, copper and polyvinyl chloride pipe materials exposed to stormwater stored in a limestone aquifer compared to an identical drinking water rig. Median alkalinity (123 mg/L) and colour (12 HU) in stormwater was significantly higher than in drinking water (82 mg/L and 1 HU) and pipe discolouration was more evident for stormwater samples. X-ray Diffraction and Fluorescence analyses confirmed this was driven by the presence of iron rich amorphous compounds in more thickly deposited sediments also consistent with significantly higher median levels of iron (∼0.56 mg/L) in stormwater compared to drinking water (∼0.17 mg/L). Water type did not influence biofilm development as determined by microbial density but faecal indicators were significantly higher for polyvinyl chloride and cement exposed to stormwater. Treatment to remove iron through aeration and filtration would reduce the potential for sediment accumulation. Operational and verification monitoring parameters to manage scaling, corrosion, colour, turbidity and microbial growth in recycled stormwater distribution networks are discussed. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  11. Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

    Science.gov (United States)

    Natalio, Filipe; André, Rute; Hartog, Aloysius F.; Stoll, Brigitte; Jochum, Klaus Peter; Wever, Ron; Tremel, Wolfgang

    2012-08-01

    Marine biofouling--the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls--is an expensive problem that is currently without an environmentally compatible solution. Biofouling leads to increased hydrodynamic drag, which, in turn, causes increased fuel consumption and greenhouse gas emissions. Tributyltin-free antifouling coatings and paints based on metal complexes or biocides have been shown to efficiently prevent marine biofouling. However, these materials can damage the environment through metal leaching (for example, of copper and zinc) and bacteria resistance. Here, we show that vanadium pentoxide nanowires act like naturally occurring vanadium haloperoxidases to prevent marine biofouling. In the presence of bromide ions and hydrogen peroxide, the nanowires catalyse the oxidation of bromide ions to hypobromous acid (HOBr). Singlet molecular oxygen (1O2) is formed and this exerts strong antibacterial activity, which prevents marine biofouling without being toxic to marine biota. Vanadium pentoxide nanowires have the potential to be an alternative approach to conventional anti-biofouling agents.

  12. Micro- and macrofouling in the OTEC program: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R; Benson, P H

    1980-06-01

    The mechanism of formation and environmental factors affecting marine biofouling are reviewed. Methods of biofouling assessment, known and potential biofouling impacts upon plant performance, and control measures applicable to OTEC are also discussed. Areas of uncertainty and the needs for continuing R and D effort to resolve such issues are indicated.

  13. Copper and copper-nickel alloys as zebra mussel antifoulants

    Energy Technology Data Exchange (ETDEWEB)

    Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

    1996-04-01

    Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

  14. A preliminary assessment of biofouling and non-indigenous marine species associated with commercial slow-moving vessels arriving in New Zealand.

    Science.gov (United States)

    Hopkins, Grant A; Forrest, Barrie M

    2010-07-01

    Vessel traffic is the primary pathway for non-indigenous marine species introductions to New Zealand, with hull fouling recognised as being an important mechanism. This article describes hull fouling on seven slow-moving commercial vessels sampled over a 1 year period. Sampling involved the collection of images and fouling specimens from different hull locations using a standardised protocol developed to assess vessel biofouling in New Zealand. A total of 29 taxa was identified by expert taxonomists, of which 24% were indigenous to New Zealand and 17% non-indigenous. No first records to New Zealand were reported, however 59% of species were classified as 'unknown' due to insufficient taxonomic resolution. The extent of fouling was low compared to that described for other slow-movers. Fouling cover, biomass and richness were on average 17.1% (SE = 1.8%), 5.2 g (SE = 1.1 g) and 0.8 (SE = 0.07) per photoquadrat (200 x 200 mm), respectively. The fouling extent was lowest on the main hull areas where the antifouling paint was in good condition. In contrast, highest levels of fouling were associated with dry-docking support strips and other niche areas of the hull where the paint condition was poor. Future studies should target vessels from a broader range of bioregions, including vessels that remain idle for extended periods (ie months) between voyages, to increase understanding of the biosecurity risks posed by international commercial slow-movers.

  15. Spatially-resolved in-situ quantification of biofouling using optical coherence tomography (OCT) and 3D image analysis in a spacer filled channel

    KAUST Repository

    Fortunato, Luca

    2016-11-21

    The use of optical coherence tomography (OCT) to investigate biomass in membrane systems has increased with time. OCT is able to characterize the biomass in-situ and non-destructively. In this study, a novel approach to process three-dimensional (3D) OCT scans is proposed. The approach allows obtaining spatially-resolved detailed structural biomass information. The 3D biomass reconstruction enables analysis of the biomass only, obtained by subtracting the time zero scan to all images. A 3D time series analysis of biomass development in a spacer filled channel under representative conditions (cross flow velocity) for a spiral wound membrane element was performed. The flow cell was operated for five days with monitoring of ultrafiltration membrane performance: feed channel pressure drop and permeate flux. The biomass development in the flow cell was detected by OCT before a performance decline was observed. Feed channel pressure drop continuously increased with increasing biomass volume, while flux decline was mainly affected in the initial phase of biomass accumulation. The novel OCT imaging approach enabled the assessment of spatial biomass distribution in the flow cell, discriminating the total biomass volume between the membrane, feed spacer and glass window. Biomass accumulation was stronger on the feed spacer during the early stage of biofouling, impacting the feed channel pressure drop stronger than permeate flux.

  16. Comparison of Alcian blue and total carbohydrate assays for quantitation of transparent exopolymer particles (TEP) in biofouling studies.

    Science.gov (United States)

    Li, Xu; Skillman, Lucy; Li, Dan; Ela, Wendell P

    2018-04-15

    Transparent exopolymer particles (TEP) and their precursors are gel-like acidic polysaccharide particles. Both TEP precursors and TEP have been identified as causal factors in fouling of desalination and water treatment systems. For comparison between studies, it is important to accurately measure the amount and fouling capacity of both components. However, the accuracy and recovery of the currently used Alcian blue based TEP measurement of different surrogates and different size fractions are not well understood. In this study, we compared Alcian blue based TEP measurements with a total carbohydrate assay method. Three surrogates; xanthan gum, pectin and alginic acid; were evaluated at different salinities. Total carbohydrate concentrations of particulates (>0.4 μm) and their precursors (10 kDa) varied depending on water salinity and method of recovery. As xanthan gum is the most frequently used surrogate in fouling studies, TEP concentration is expressed as xanthan gum equivalents (mg XG eq /L) in this study. At a salinity of 35 mg/L sea salt, total carbohydrate assays showed a much higher particulate TEP fraction for alginic acid (38%) compared to xanthan gum (9%) and pectin (12%). The concentrations of particulate TEP therefore may only represent ∼10% of the total mass; while precursor TEP represents ∼80% of the total TEP. This highlights the importance of reporting both particulate and precursor TEP for membrane biofouling studies. The calculated concentrations of TEP and their precursors in seawater samples are also highly dependent on type of surrogate and resulting calibration factor. A linear correlation between TEP recovery and calibration factor was demonstrated in this study for all three surrogates. The relative importance and accuracy of measurement method, particulate size, surrogate type, and recovery are described in detail in this study. Copyright © 2017. Published by Elsevier Ltd.

  17. An anaerobic-aerobic sequential batch process with simultaneous methanogenesis and short-cut denitrification for the treatment of marine biofoulings.

    Science.gov (United States)

    Akizuki, S; Toda, T

    2018-04-01

    Although combination of denitritation and methanogenesis for wastewater treatment has been widely investigated, an application of this technology to solid waste treatment has been rarely studied. This study investigated an anaerobic-aerobic batch system with simultaneous denitritation-methanogenesis as an effective treatment for marine biofoulings, which is a major source of intermittently discharged organic solid wastes. Preliminary NO 2 - -exposed sludge was inoculated to achieve stable methanogenesis process without NO 2 - inhibition. Both high NH 4 + -N removal of 99.5% and high NO 2 - -N accumulation of 96.4% were achieved on average during the nitritation step. Sufficient CH 4 recovery of 101 L-CH 4 kg-COD -1 was achieved, indicating that the use of NO 2 - -exposed sludge is effective to avoid NO 2 - inhibition on methanogenesis. Methanogenesis was the main COD utilization pathway when the substrate solubilization occurred actively, while denitritation was the main when solubilization was limited because of substrate shortage. The results showed a high COD removal efficiency of 96.0% and a relatively low nitrogen removal efficiency of 64.4%. Fitting equations were developed to optimize the effluent exchange ratio. The estimated results showed that the increase of effluent exchange ratio during the active solubilization period increased the nitrogen removal efficiency but decreased CH 4 content in biogas. An appropriate effluent exchange ratio with high anaerobic effluent quality below approximately 120 mg-N L -1 as well as sufficient CH 4 gas quality which can be used as fuel for gas engine generator was achieved by daily effluent exchange of 80% during the first week and 5% during the subsequent 8 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Assessing the port to port risk of vessel movements vectoring non-indigenous marine species within and across domestic Australian borders.

    Science.gov (United States)

    Campbell, Marnie L; Hewitt, Chad L

    2011-07-01

    Biofouling of vessels is implicated as a high risk transfer mechanism of non-indigenous marine species (NIMS). Biofouling on international vessels is managed through stringent border control policies, however, domestic biofouling transfers are managed under different policies and legislative arrangements as they cross internal borders. As comprehensive guidelines are developed and increased compliance of international vessels with 'clean hull' expectations increase, vessel movements from port to port will become the focus of biosecurity management. A semi-quantitative port to port biofouling risk assessment is presented that evaluates the presence of known NIMS in the source port and determines the likelihood of transfer based on the NIMS association with biofouling and environmental match between source and receiving ports. This risk assessment method was used to assess the risk profile of a single dredge vessel during three anticipated voyages within Australia, resulting in negligible to low risk outcomes. This finding is contrasted with expectations in the literature, specifically those that suggest slow moving vessels pose a high to extreme risk of transferring NIMS species.

  19. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.; Wexler, A. D.; Bucs, Szilard; Dreszer, C.; Zwijnenburg, A.; Flemming, H. C.; Kruithof, J. C.; Vrouwenvelder, Johannes S.

    2015-01-01

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies

  20. Effects of cathodic polarisation on carbohydrate metabolism in Amphora coffeaeformis, a marine fouling diatom

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; McCarrol, D.; Evans, L.V.; Edyvean, R.G.J.

    stream_size 15 stream_content_type text/plain stream_name Biofouling_7_171.pdf.txt stream_source_info Biofouling_7_171.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  1. Carbohydrate production by Amphora coffeaeformis, marine fouling diatom

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Evans, L.; Edyvean, R.G.J.

    stream_size 11 stream_content_type text/plain stream_name biofouling_7_81.pdf.txt stream_source_info biofouling_7_81.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  2. Exopolysaccharide production by Vibrio fischeri, a fouling marine bacterium

    Digital Repository Service at National Institute of Oceanography (India)

    Rodrigues, C.L; Bhosle, N.B.

    stream_size 8 stream_content_type text/plain stream_name Biofouling_4_301.pdf.txt stream_source_info Biofouling_4_301.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  3. Molecular characterization, biofilm analysis and experimental biofouling study of Fusarium isolates from recent cases of fungal keratitis in New York State

    Directory of Open Access Journals (Sweden)

    Samsonoff William A

    2007-01-01

    Full Text Available Abstract Background To characterize Fusarium isolates from recent cases of fungal keratitis in contact lens wearers, and to investigate fungal association with MoistureLoc solution. Methods We studied six fungal isolates from recent cases of keratitis in New York State. The isolates were characterized by nucleotide sequencing and phylogenetic analyses of multiple genes, and then typed using minisatellite and microsatellite probes. Experimental fungal biofilm formation was tested by standard methods. MoistureLoc solutions were tested in biofouling studies for their efficacy in elimination of Fusarium contamination. Results Fusarium solani – corneal ulcers (2 isolates, lens case (1 isolate, and F. oxysporum – corneal ulcer (1 isolate, eye (1 isolate, were recovered from five patients. An opened bottle of MoistureLoc solution provided by a patient also yielded F. solani. Two distinct genotypes of F. solani as well as of F. oxysporum were present in the isolated strains. Remarkably, F. solani strains from the lens case and lens solution in one instance were similar, based on phylogenetic analyses and molecular typing. The solution isolate of F. solani formed biofilm on contact lenses in control conditions, but not when co-incubated with MoistureLoc solution. Both freshly opened and 3-month old MoistureLoc solutions effectively killed F. solani and F. oxysporum, when fungal contamination was simulated under recommended lens treatment regimen (4-hr. However, simulation of inappropriate use (15 – 60 min led to the recovery of less than 1% of original inoculum of F. solani or F. oxysporum. Conclusion Temporary survival of F. solani and F. oxysporum in MoistureLoc suggested that improper lens cleaning regimen could be a possible contributing factor in recent infections.

  4. Actiniarian Sea anemone fauna of India

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.

    stream_size 11 stream_content_type text/plain stream_name Mar_Biofouling_Power_Plants_1990_218.pdf.txt stream_source_info Mar_Biofouling_Power_Plants_1990_218.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  5. Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communities.

    Science.gov (United States)

    Brown, Norah E M; Milazzo, Marco; Rastrick, Samuel P S; Hall-Spencer, Jason M; Therriault, Thomas W; Harley, Christopher D G

    2018-01-01

    Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO 2 at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO 2 change and, if high pCO 2 is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO 2 stress, or are worsened by departures from prior high pCO 2 conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO 2 gradient to assess the importance of the timing and duration of high pCO 2 exposure (i.e., discrete events at different stages of successional development vs. continuous exposure) on patterns of colonization and succession in a benthic fouling community. We show that succession at the acidified site was initially delayed (less community change by 8 weeks) but then caught up over the next 4 weeks. These changes in succession led to homogenization of communities maintained in or transplanted to acidified conditions, and altered community structure in ways that reflected both short- and longer-term acidification history. These community shifts are likely a result of interspecific variability in response to increased pCO 2 and changes in species interactions. High pCO 2 altered biofilm development, allowing serpulids to do best at the acidified site by the end of the experiment, although early (pretransplant) negative effects of pCO 2 on recruitment of these worms were still detectable. The ascidians Diplosoma sp. and Botryllus sp. settled later and were more tolerant to acidification. Overall, transient and persistent acidification-driven changes in the biofouling community, via both past and more recent exposure, could have important

  6. Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

    Directory of Open Access Journals (Sweden)

    L. Vanysacker

    2013-01-01

    Full Text Available Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development.

  7. Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

    Science.gov (United States)

    Vanysacker, L.; Denis, C.; Declerck, P.; Piasecka, A.; Vankelecom, I. F. J.

    2013-01-01

    Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development. PMID:23986906

  8. Development of biofilm on materials exposed in coastal waters near to a desalination plant intake at Kudankulam, east coast of India

    International Nuclear Information System (INIS)

    Satheesh, S.; Godwin Wesly, S.

    2007-01-01

    Full text: Biofouling is a major problem in power plant cooling systems, desalination plants and navigation etc. As biofouling is a site specific problem, studies on the various aspects of biofouling to a particular region is necessary for taking better antifouling strategy. This study was carried out at Kudankulam coastal waters, with an objective to analyse the process of biofilm formation and its further succession on Perspex test panels. The development of biofilm was observed over a period of 14 days during January and September 2005. Results indicated that the biofilm formation was initiated by bacteria, followed by diatom and macro algal spores. Psuedomonas and Desulphovibrio were the predominant bacterial genera observed during the initial 48 hours of panel exposure. Diatom community was dominated by restricted number of genera such as Navicula, Nitzschia and Amphora. The hydrobiological parameters such as temperature, salinity, dissolved oxygen, phosphate, nitrite and nitrate were examined in the context of biofouling activity in the coastal waters

  9. Microfouling on biocidal and non-biocidal antifouling coatings

    Directory of Open Access Journals (Sweden)

    Thirumahal Muthukrishnan

    2015-01-01

    Full Text Available Although antifouling marine paints have been used to prevent biofouling, not much is known about their effectiveness in preventing attachment of microorganisms. The current study aims at estimating the abundance of bacteria within biofilms developed on various commercial antifouling coatings in Marina Bandar Rowdha and Marina Shangri La, Oman. Coatings tested included Pettit #1863 and #1792, West Marine #11046620, #5566252 and #10175206, Hempel Hard Racing #76484, Hempel Olympic #86950, Hempasil X3 and International YBA920. All coatings were applied on clean plastic slides. Slides without any coating were used as controls. Microbial biofilms were harvested after 2, 7 and 14 days of biofouling. Bacterial density was estimated using epifluorescence microscopy. There was a significant difference between the various treatments (coatings and control after 2, 7 and 14 days of biofouling. Although there were significant differences between both locations after 2 and 14 days of biofouling, no significant difference was observed after 7 days of biofouling at both locations. At Shangri La, the lowest bacterial density was found on International YBA920, Pettit #1792 and Hempasil X3 after 2 days, 7 days and 14 days respectively in comparison to the control treatments. However at Bandar Rowdha, International YBA920 showed the lowest bacterial density after 2 days while West Marine #10175206 showed the lowest bacterial density after both 7 days and 14 days of biofouling in comparison to the control treatment. The differential performance of tested antifouling coatings may be attributed to several factors including varying environmental conditions, difference in microfouling communities, time of exposure and physical and chemical properties of antifouling coating.

  10. A new diatom growth inhibition assay using the XTT colorimetric method.

    Science.gov (United States)

    Jiang, Weina; Akagi, Takuya; Suzuki, Hidekazu; Takimoto, Ayaka; Nagai, Hiroshi

    2016-01-01

    Marine biofouling, which leads to significant operational stress and economic damage on marine infrastructures, is a major problem in marine related industries. Currently, the most common way to avoid marine biofouling involves the use of biocidal products in surface coatings. However, the need for environmentally friendly antibiofouling compounds has increased rapidly with the recent global prohibition of harmful antifoulants, such as tributyltin (TBT). In particular, periphytic diatoms have been shown to contribute significantly to biofilms, which play an important role in biofouling. Therefore, inhibiting the proliferation of fouling diatoms is a very important step in the prevention of marine biofouling. In this study, we developed a new, rapid, accurate, and convenient growth inhibition assay using the XTT colorimetric method to prevent the growth of the fouling periphytic diatom, Nitzschia amabilis Hidek. Suzuki (replaced synonym, Nitzschia laevis Hustedt). The feasibility of this method was verified by determining the growth inhibition activities of two standard photosynthetic inhibitors, DCMU and CuSO4. However, neither inhibitor had any cytotoxic activities at the range of concentrations tested. Moreover, this method was applied by screening and purification of herbicidic but non-cytotoxic compounds from cyanobacteria extracts. Our results demonstrate the utility of this newly established growth inhibition assay for the identification of marine anti-biofouling compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Involvement of reactive oxygen species in the electrochemical inhibition of barnacle (Amphibalanus amphitrite) settlement

    Science.gov (United States)

    Rodolfo E. Perez-Roa; Marc A. Anderson; Dan Rittschof; Christopher G. Hunt; Daniel R. Noguera

    2009-01-01

    The role of reactive oxygen species (ROS) in electrochemical biofouling inhibition was investigated using a series of abiotic tests and settlement experiments with larvae of the barnacle Amphibalanus amphitrite, a cosmopolitan fouler. Larval settlement, a measure of biofouling potential, was reduced from 43% ± 14% to 5% ± 6% upon the application of...

  12. Bacterial Growth on Chitosan-Coated Polypropylene Textile

    Science.gov (United States)

    Erben, D.; Hola, V.; Jaros, J.; Rahel, J.

    2012-01-01

    Biofouling is a problem common in all systems where microorganisms and aqueous environment meet. Prevention of biofouling is therefore important in many industrial processes. The aim of this study was to develop a method to evaluate the ability of material coating to inhibit biofilm formation. Chitosan-coated polypropylene nonwoven textile was prepared using dielectric barrier discharge plasma activation. Resistance of the textile to biofouling was then tested. First, the textile was submerged into a growth medium inoculated with green fluorescein protein labelled Pseudomonas aeruginosa. After overnight incubation at 33°C, the textile was observed using confocal laser scanning microscopy for bacterial enumeration and biofilm structure characterisation. In the second stage, the textile was used as a filter medium for prefiltered river water, and the pressure development on the in-flow side was measured to quantify the overall level of biofouling. In both cases, nontreated textile samples were used as a control. The results indicate that the chitosan coating exhibits antibacterial properties. The developed method is applicable for the evaluation of the ability to inhibit biofilm formation. PMID:23724330

  13. Determination of Adsorption Capacity and Kinetics of Amidoxime-Based Uranium Adsorbent Braided Material in Unfiltered Seawater Using a Flume Exposure System

    International Nuclear Information System (INIS)

    Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.; Park, Jiyeon; Bonheyo, George T.; Jeters, Robert T.; Schlafer, Nicholas J.; Wood, Jordana R.

    2015-01-01

    PNNL has developed a recirculating flume system for exposing braided adsorbent material to natural seawater under realistic temperature and flow-rate exposure conditions. The flumes are constructed of transparent acrylic material; they allow external light to pass into the flumes and permit photosynthetic growth of naturally present marine organisms (biofouling). Because the system consists of two flumes, replicate experiments can be conducted in which one of the flumes can be manipulated relative to the other. For example, one flume can be darkened to eliminate light exposure by placing a black tarp over the flume such that dark/light experiments can be conducted. Alternatively, two different braided adsorbents can be exposed simultaneously with no potential cross contamination issues. This report describes the first use of the PNNL flume system to study the impact of biofouling on adsorbent capacity. Experiments were conducted with the ORNL AI8 braided adsorbent material in light-exposed and darkened flumes for a 42-day exposure experiment. The major objective of this effort is to develop a system for the exposure of braided adsorbent material to unfiltered seawater, and to demonstrate the system by evaluating the performance of adsorption material when it is exposed to natural marine biofouling as it would be when the technology is used in the marine environment. Exposures of amidoxime-based polymeric braid adsorbents prepared by Oak Ridge Natural Laboratory (ORNL) were exposed to ambient seawater at 20°C in a flume system. Adsorption kinetics and adsorption capacity were assessed using time series determinations of uranium adsorption and one-site ligand saturation modeling. Biofouling in sunlight surface seawater has the potential to significantly add substantial biogenic mass to adsorption material when it is exposed for periods greater than 21 days. The observed biomass increase in the light flume was approximately 80% of the adsorbent mass after 42 days

  14. Determination of Adsorption Capacity and Kinetics of Amidoxime-Based Uranium Adsorbent Braided Material in Unfiltered Seawater Using a Flume Exposure System

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Park, Jiyeon [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Bonheyo, George T. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Jeters, Robert T. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Schlafer, Nicholas J. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.

    2015-08-31

    PNNL has developed a recirculating flume system for exposing braided adsorbent material to natural seawater under realistic temperature and flow-rate exposure conditions. The flumes are constructed of transparent acrylic material; they allow external light to pass into the flumes and permit photosynthetic growth of naturally present marine organisms (biofouling). Because the system consists of two flumes, replicate experiments can be conducted in which one of the flumes can be manipulated relative to the other. For example, one flume can be darkened to eliminate light exposure by placing a black tarp over the flume such that dark/light experiments can be conducted. Alternatively, two different braided adsorbents can be exposed simultaneously with no potential cross contamination issues. This report describes the first use of the PNNL flume system to study the impact of biofouling on adsorbent capacity. Experiments were conducted with the ORNL AI8 braided adsorbent material in light-exposed and darkened flumes for a 42-day exposure experiment. The major objective of this effort is to develop a system for the exposure of braided adsorbent material to unfiltered seawater, and to demonstrate the system by evaluating the performance of adsorption material when it is exposed to natural marine biofouling as it would be when the technology is used in the marine environment. Exposures of amidoxime-based polymeric braid adsorbents prepared by Oak Ridge Natural Laboratory (ORNL) were exposed to ambient seawater at 20°C in a flume system. Adsorption kinetics and adsorption capacity were assessed using time series determinations of uranium adsorption and one-site ligand saturation modeling. Biofouling in sunlight surface seawater has the potential to significantly add substantial biogenic mass to adsorption material when it is exposed for periods greater than 21 days. The observed biomass increase in the light flume was approximately 80% of the adsorbent mass after 42 days

  15. Effect of Silver or Copper Nanoparticles-Dispersed Silane Coatings on Biofilm Formation in Cooling Water Systems

    Science.gov (United States)

    Ogawa, Akiko; Kanematsu, Hideyuki; Sano, Katsuhiko; Sakai, Yoshiyuki; Ishida, Kunimitsu; Beech, Iwona B.; Suzuki, Osamu; Tanaka, Toshihiro

    2016-01-01

    Biofouling often occurs in cooling water systems, resulting in the reduction of heat exchange efficiency and corrosion of the cooling pipes, which raises the running costs. Therefore, controlling biofouling is very important. To regulate biofouling, we focus on the formation of biofilm, which is the early step of biofouling. In this study, we investigated whether silver or copper nanoparticles-dispersed silane coatings inhibited biofilm formation in cooling systems. We developed a closed laboratory biofilm reactor as a model of a cooling pipe and used seawater as a model for cooling water. Silver or copper nanoparticles-dispersed silane coating (Ag coating and Cu coating) coupons were soaked in seawater, and the seawater was circulated in the laboratory biofilm reactor for several days to create biofilms. Three-dimensional images of the surface showed that sea-island-like structures were formed on silane coatings and low concentration Cu coating, whereas nothing was formed on high concentration Cu coatings and low concentration Ag coating. The sea-island-like structures were analyzed by Raman spectroscopy to estimate the components of the biofilm. We found that both the Cu coating and Ag coating were effective methods to inhibit biofilm formation in cooling pipes. PMID:28773758

  16. Characterization of Membrane Foulants in Full-scale and Lab-scale Membrane Bioreactors for Wastewater Treatment and Reuse

    KAUST Repository

    Matar, Gerald

    2015-12-01

    Membrane bioreactors (MBRs) offer promising solution for wastewater treatment and reuse to address the problem of water scarcity. Nevertheless, this technology is still facing challenges associated with membrane biofouling. This phenomenon has been mainly investigated in lab-scale MBRs with little or no insight on biofouling in full-scale MBR plants. Furthermore, the temporal dynamics of biofouling microbial communities and their extracellular polymeric substances (EPS) are less studied. Herein, a multidisciplinary approach was adopted to address the above knowledge gaps in lab- and full-scale MBRs. In the full-scale MBR study, 16S rRNA gene pyrosequencing with multivariate statistical analysis revealed that the early and mature biofilm communities from five full-scale MBRs differed significantly from the source community (i.e. activated sludge), and random immigration of species from the source community was unlikely to shape the community structure of biofilms. Also, a core biofouling community was shared between the five MBR plants sampled despite differences in their operating conditions. In the lab-scale MBR studies, temporal dynamics of microbial communities and their EPS products were monitored on different hydrophobic and hydrophilic membranes during 30 days. At the early stages of filtration (1 d), the same early colonizers belonging to the class Betaproteobacteria were identified on all the membranes. However, their relative abundance decreased on day 20 and 30, and sequence reads belonging to the phylum Firmicutes and Chlorobi became dominant on all the membranes on day 20 and 30. In addition, the intrinsic membrane characteristic did not select any specific EPS fractions at the initial stages of filtration and the same EPS foulants developed with time on the hydrophobic and hydrophilic membranes. Our results indicated that the membrane surface characteristics did not select for specific biofouling communities or EPS foulants, and the same early

  17. Functionalizing aluminum substrata by quaternary ammonium for antifouling performances

    Science.gov (United States)

    He, Xiaoyan; Suo, Xinkun; Bai, Xiuqin; Yuan, Chengqing; Li, Hua

    2018-05-01

    Due to the great loss induced by biofouling, developing new strategies for combating biofouling has attracted extensive attention. Quaternary ammonium salts are potent cationic antimicrobials used in consumer products and their use for surface immobilization could create a contact-active antimicrobial layer. Here we report the facile preparation of a contact-active antifouling coating by tethering polyethyleneimine (PEI) onto flat/nanostructured aluminum surface by hydrogen bonding between PEI and AlOOH. Quaternized PEI (QPEI) is obtained through quaternization reactions. Biofouling testing suggests excellent antifouling performances of the samples by declining the adhesion of 95% Phaeodactylum tricornutum and 98% of Chlorella pyrenoidosa. The antifouling properties of PEI/QPEI are attributed predominately to their hydrophilic and antimicrobial nature. The technical route of PEI/QPEI surface grafting shows great potential for modifying marine infrastructures for enhanced antifouling performances.

  18. Fouling communities and degradation of archeological metals in the coastal sea of the Southwestern Gulf of Mexico.

    Science.gov (United States)

    López Garrido, Pedro H; González-Sánchez, J; Escobar Briones, Elva

    2015-01-01

    Corrosion and biofouling phenomena of cast iron and brass were evaluated under natural conditions to determine the degradation process of archeological artifacts. Field exposure studies of experimental materials were conducted over 15 months at an offshore position in the sea of Campeche in the Gulf of Mexico. Corrosion was determined by gravimetric measurements. The community structure of the benthic assemblage inhabiting the surfaces of both materials was evaluated. A total of 53 species was identified. The community in both cases was composed of a small number of species. Encrusting, attached and erect life forms were dominant on iron. Attached life forms were dominant on brass. Biofouling produced a decrease in the weight loss measurements of cast iron samples. Biofouling provided a beneficial factor for in situ preservation of iron archeological artifacts in wreck sites.

  19. An overall view on corrosion and bio-fouling problems in sea water cooling systems at MAPS

    International Nuclear Information System (INIS)

    Satyanarayanan, V.; Umapathy, P.; Bhaskaran, R.; Nagarajan, J.; Pradeep, Jeena; Krishna Rao, K.S.

    2008-01-01

    MAPS is a twin unit-220 MWe Pressurised Heavy Water Reactor (PHWR) nuclear power station using seawater as cooling medium in main steam condensers and in the Process Sea Water Heat Exchangers (PSWHXs). The seawater system consists of intake structure, submarine tunnel, fore-bay and pump house, travelling water screens, associated pumps and piping, heat-exchangers and out-fall structure. The horseshoe type submarine tunnel of length 468 metres and diameter 3.85 metres carrying ∼ 1.3 lakh m 3 /hr seawater from the intake structure to the pump house is lined with special concrete of 225 mm thickness. The major portion of piping carrying seawater is made of concrete and coal-tar based epoxy coated mild steel. Some portions of the mild steel pipes were gunnited and coated with araldite to minimise corrosion and fouling. The tubes of the condensers and the PSWHXs are of aluminium brass and the tube sheets are of aluminium bronze. The water boxes are rubber-lined with 3 mm thick neoprene and 2% magnesium iron sacrificial anodes are also provided in the water boxes to minimise corrosion. Plastic inserts are installed at the inlets of the tubes to prevent damage due to impingement attack and erosion. Ferrous sulphate dosing is being carried out to minimize the corrosion of aluminium brass tubes. Biofouling control (both Micro/Macro) is effected by gaseous chlorination at the rate of 30 - 40 Kg/hr for ∼ 20 hrs daily with residuals of 0.20 ppm. Further, booster dose (Liquid chlorine injection through evaporator) is given twice a week with a residual of ∼ 0.50 ppm and the dose required for this treatment is met by using evaporators. The major marine species identified in the intake and forebay were large barnacles and green mussels whereas the species identified in the PSWHXs were small size Barnacles (B. Reticulatus, 3 - 4 mm in size) and Mussels ( M.Striatulus, 5 - 8 mm in size). The main condensers are being cleaned during planned outages whereas it is not possible to

  20. Bio-inspired Design Approached Antifouling Strategies

    Science.gov (United States)

    Fitzsimons, L.; Chapman, J.; Lawlor, A.; Regan, F.

    2012-04-01

    Biofouling exists as the undesirable accumulation of flora and fauna on a given substrate when immersed into an aquatic media. Its presence causes a range of deleterious effects for anyone faced in tackling the problem, which is more than often financially testing. Generally, the initial biofouling stage is stochastic and the attachment of microorganisms held fast in biofilm matrices is irreversible. Stability of the biofilm occurs when exopolymeric substances (EPS) are produced forming a protective surrounding, allowing the cohered microorganisms to colonise and thrive upon the surface. Therefore, if this initial stage of biofilm development can be prevented then it could be possible to prevent subsequent macro events that ensue. Environmental monitoring is one area that faces this challenge and forms the impetus of the work presented herein. In order to improve a monitoring device's lifetime, surface coatings with biocidal agents are applied to counteract these steps. This work shows the development of a range of novel materials, which demonstrate the ability to counteract and inhibit the initial stages of biofouling for monitoring devices. Natural bio-inspired surfaces have been developed using nano-functionalised coatings. All materials are tested in the field and positive results in reducing the biofouling challenge are demonstrated. The results from the deployment of antifouling materials, together with real-time, long-term water quality data from the test site are also shown.

  1. Quantitative measurement and visualization of biofilm O 2 consumption rates in membrane filtration systems

    KAUST Repository

    Prest, Emmanuelle I E C

    2012-03-01

    There is a strong need for techniques enabling direct assessment of biological activity of biofouling in membrane filtration systems. Here we present a new quantitative and non-destructive method for mapping O 2 dynamics in biofilms during biofouling studies in membrane fouling simulators (MFS). Transparent planar O 2 optodes in combination with a luminescence lifetime imaging system were used to map the two-dimensional distribution of O 2 concentrations and consumption rates inside the MFS. The O 2 distribution was indicative for biofilm development. Biofilm activity was characterized by imaging of O 2 consumption rates, where low and high activity areas could be clearly distinguished. The spatial development of O 2 consumption rates, flow channels and stagnant areas could be determined. This can be used for studies on concentration polarization, i.e. salt accumulation at the membrane surface resulting in increased salt passage and reduced water flux. The new optode-based O 2 imaging technique applied to MFS allows non-destructive and spatially resolved quantitative biological activity measurements (BAM) for on-site biofouling diagnosis and laboratory studies. The following set of complementary tools is now available to study development and control of biofouling in membrane systems: (i) MFS, (ii) sensitive pressure drop measurement, (iii) magnetic resonance imaging, (iv) numerical modelling, and (v) biological activity measurement based on O 2 imaging methodology. © 2011 Elsevier B.V.

  2. Biodiversity characterisation and hydrodynamic consequences of marine fouling communities on marine renewable energy infrastructure in the Orkney Islands Archipelago, Scotland, UK.

    Science.gov (United States)

    Want, Andrew; Crawford, Rebecca; Kakkonen, Jenni; Kiddie, Greg; Miller, Susan; Harris, Robert E; Porter, Joanne S

    2017-08-01

    As part of ongoing commitments to produce electricity from renewable energy sources in Scotland, Orkney waters have been targeted for potential large-scale deployment of wave and tidal energy converting devices. Orkney has a well-developed infrastructure supporting the marine energy industry; recently enhanced by the construction of additional piers. A major concern to marine industries is biofouling on submerged structures, including energy converters and measurement instrumentation. In this study, the marine energy infrastructure and instrumentation were surveyed to characterise the biofouling. Fouling communities varied between deployment habitats; key species were identified allowing recommendations for scheduling device maintenance and preventing spread of invasive organisms. A method to measure the impact of biofouling on hydrodynamic response is described and applied to data from a wave-monitoring buoy deployed at a test site in Orkney. The results are discussed in relation to the accuracy of the measurement resources for power generation. Further applications are suggested for future testing in other scenarios, including tidal energy.

  3. Thin Film Polyamide Membranes with Photoresponsive Antibacterial Activity

    KAUST Repository

    Duong, Phuoc H. H.

    2017-08-09

    Membranes containing a photosensitizer molecule as part of the selective layer are proposed with demonstrated anti-biofouling activity. For the membrane preparation, mixtures of an amine-functionalized photosensitizer molecule, (5,10,15,20-(tetra-4-aminophenyl)porphyrin) and m-phenylene diamine (MPD) reacted with trimesoyl chloride (TMC) by interfacial polymerization to form thin polyamide films on top of an asymmetric porous support. A highly permeable membrane (35.4 Lm−2h−1bar−1) with 99 % rejection of Brilliant Blue R (826 g/mol) was obtained using 0.25 wt% porphyrin and 0.75 wt% MPD as amine monomers. Under visible light exposure, singlet oxygen (1O2) is generated in the porphyrin containing-polyamide film, reaching the bacteria in the feed by diffusion and enhancing the biofouling resistance and anti-microbial activity. Anti-biofouling and anti-microbial photoactivity in solution are demonstrated on Staphylococcus aureus at different porphyrin concentrations and light exposure time.

  4. Thin Film Polyamide Membranes with Photoresponsive Antibacterial Activity

    KAUST Repository

    Duong, Phuoc H. H.; Hong, Pei-Ying; Musteata, Valentina-Elena; Peinemann, Klaus-Viktor; Nunes, Suzana Pereira

    2017-01-01

    Membranes containing a photosensitizer molecule as part of the selective layer are proposed with demonstrated anti-biofouling activity. For the membrane preparation, mixtures of an amine-functionalized photosensitizer molecule, (5,10,15,20-(tetra-4-aminophenyl)porphyrin) and m-phenylene diamine (MPD) reacted with trimesoyl chloride (TMC) by interfacial polymerization to form thin polyamide films on top of an asymmetric porous support. A highly permeable membrane (35.4 Lm−2h−1bar−1) with 99 % rejection of Brilliant Blue R (826 g/mol) was obtained using 0.25 wt% porphyrin and 0.75 wt% MPD as amine monomers. Under visible light exposure, singlet oxygen (1O2) is generated in the porphyrin containing-polyamide film, reaching the bacteria in the feed by diffusion and enhancing the biofouling resistance and anti-microbial activity. Anti-biofouling and anti-microbial photoactivity in solution are demonstrated on Staphylococcus aureus at different porphyrin concentrations and light exposure time.

  5. Evaluating the effect of different draw solutes in a baffled osmotic membrane bioreactor-microfiltration using optical coherence tomography with real wastewate

    KAUST Repository

    Pathak, Nirenkumar

    2018-05-03

    This study investigated the performance of an integrated osmotic and microfiltration membrane bioreactor for real sewage employing baffles in the reactor. To study the biofouling development on forward osmosis membranes optical coherence tomography (OCT) technique was employed. On-line monitoring of biofilm growth on a flat sheet cellulose triacetate forward osmosis (CTA-FO) membrane was conducted for 21 days. Further, the process performance was evaluated in terms of water flux, organic and nutrient removal, microbial activity in terms of soluble microbial products (SMP) and extracellular polymeric substance (EPS), and floc size. The measured biofouling layer thickness was in the order sodium chloride (NaCl) > ammonium sulfate (SOA) > potassium dihydrogen phosphate (KH2PO4). Very high organic removal (96.9±0.8 %) and reasonably good nutrient removal efficiency (85.2±1.6 % TN) was achieved. The sludge characteristics and biofouling layer thickness suggest that less EPS and higher floc size were the governing factors for less fouling.

  6. Efficiency of copper and cupronickel substratum to resist development of diatom biofilms

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Anil, A.C.

    Incorporated, pp. 445-486 French, M.S., Evans, L.V., 1988. The effects of copper and zinc on growth of the fouling diatoms Amphora and Amphiprora. Biofouling. 1, 3-18 Fitridge, I., Dempster, T., Guenther, J., de Nys, R., 2012. The impact and control...–694. Muthukrishnan et al. 2014Muthukrishnan, T., Abed, R.M.M., Dobretsov, S., Kidd, B., Finnie, A.A., 2014. Long-term microfouling on commercial biocidal fouling control coatings. Biofouling. 30(10), 1155-1164. Parsons TR, Maita Y, Lalli CM (1984) A manual...

  7. A System-Wide Approach to Identify the Mechanisms of Barnacle Attachment: Toward the Discovery of New Antifouling Compounds

    KAUST Repository

    Al-Aqeel, Sarah

    2015-11-01

    Biofouling is a significant economic problem, particularly for marine and offshore oil industries. The acorn barnacle (Amphibalanus (Balanus) amphitrite) is the main biofouling organism in marine environments. Environmental conditions, the physiology of the biofouling organism, the surrounding microbial community, and the properties of the substratum can all influence the attachment of biofouling organisms to substrates. My dissertation investigated the biological processes involved in B. amphitrite development and attachment in the unique environment of the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41‰. I profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI, and cyprid) and identified 65,784 expressed contigs and 1387 expressed proteins by quantitative proteomics. During the planktonic stage, genes related to osmotic stress, salt stress, the hyperosmotic response, and the Wnt signaling pathway were strongly up-regulated, hereas genes related to the MAPK pathway, lipid metabolism, and cuticle development were down-regulated. In the transition from the nauplius VI to cyprid stages, there was up-regulation of genes involved in blood coagulation, cuticle development, and eggshell formation, and down-regulation of genes in the nitric oxide pathway, which stimulates the swimming and feeding responses of marine invertebrates. This system-wide integrated approach elucidated the development and attachment pathways important in B. amphitrite. Enzymes and metabolites in these pathways are potential molecular targets for the development of new antifouling compounds.

  8. Iron in the aquifer system of Suffolk County, New York, 1990–98

    Science.gov (United States)

    Brown, Craig J.; Walter, Donald A.; Colabufo, Steven

    1999-01-01

    High concentrations of dissolved iron in ground water contribute to the biofouling of public-supply wells, and the treatment and remediation of biofouling are costly. Water companies on Long Island, N.Y., spend several million dollars annually to recondition, redevelop, and replace supply wells and distribution lines; treat dissolved iron with sequestering agents or by filtration; and respond to iron-related complaints by customers. This report summarizes the results of studies done by the U.S. Geological Survey, in cooperation with the Suffolk County Water Authority, to characterize the geochemistry and microbiology of iron in the aquifer system of Suffolk County. This information should be helpful for the siting and operation of supply wells.Concentrations of dissolved iron in Long Island's ground water, and the frequency of iron biofouling of wells, are highest in ground-water-discharge zones, particularly near the south shore. Ground water along a deep north-south flowpath of the Magothy aquifer in southwestern Suffolk County becomes anaerobic (oxygen deficient) and Fe(III) reducing at a distance of 8 to 10 kilometers south of the ground-water divide, and this change coincides with the downgradient increase in dissolved iron concentrations. The distribution of organic carbon, and the distribution and local variations in reactivity of Fe(III), in Magothy aquifer sediments have resulted in localized differences in redox microenvironments. For example, Fe(III)-reducing zones are associated with anaerobic conditions, where relatively large amounts of Fe(III) oxyhydroxide grain coatings are present, whereas sulfate-reducing zones are associated with lignite-rich lenses of silt and clay and appear to have developed in response to the depletion of available Fe(III) oxyhydroxides. The sulfate-reducing zones are characterized by relatively low concentrations of dissolved iron (resulting from iron-disulfide precipitation) and may be large enough to warrant water

  9. Biological control of biofilms on membranes by metazoans.

    Science.gov (United States)

    Klein, Theresa; Zihlmann, David; Derlon, Nicolas; Isaacson, Carl; Szivak, Ilona; Weissbrodt, David G; Pronk, Wouter

    2016-01-01

    Traditionally, chemical and physical methods have been used to control biofouling on membranes by inactivating and removing the biofouling layer. Alternatively, the permeability can be increased using biological methods while accepting the presence of the biofouling layer. We have investigated two different types of metazoans for this purpose, the oligochaete Aelosoma hemprichi and the nematode Plectus aquatilis. The addition of these grazing metazoans in biofilm-controlled membrane systems resulted in a flux increase of 50% in presence of the oligochaetes (Aelosoma hemprichi), and a flux increase of 119-164% in presence of the nematodes (Plectus aquatilis) in comparison to the control system operated without metazoans. The change in flux resulted from (1) a change in the biofilm structure, from a homogeneous, cake-like biofilm to a more heterogeneous, porous structure and (2) a significant reduction in the thickness of the basal layer. Pyrosequencing data showed that due to the addition of the predators, also the community composition of the biofilm in terms of protists and bacteria was strongly affected. The results have implications for a range of membrane processes, including ultrafiltration for potable water production, membrane bioreactors and reverse osmosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Natural cleaning of the black-lip pearl oyster Pinctada margaritifera by butterflyfishes (Chaetodon) in French Polynesia

    Science.gov (United States)

    Bertucci, Frédéric; Legraverant, Yohann; Berthe, Cécile; Brooker, Rohan M.; Lo, Cédrik; Lecchini, David

    2016-12-01

    Biofouling increases the operational and economic costs associated with pearl production. As current procedures for reducing oyster biofouling can be detrimental to survival and growth and may pollute the surrounding environment developing alternative, biologically-mediated, methods could potentially increase both production and ecological sustainability. With this in mind, the present study investigated natural cleaning of black-lipped pearl oysters, Pinctada margaritifera, by butterflyfishes (Chaetodon). The feeding behaviour of six butterflyfish species was examined at Rangiroa Atoll, French Polynesia: Chaetodon auriga, Chaetodon citrinellus, Chaetodon ephippium, Chaetodon lunulatus, Chaetodon trifascialis and Chaetodon ulietensis. All species cleaned the surface of pearl oysters by removing epibionts (from 16% to 40% of total biomass), although dietary variation may explain different cleaning efficiencies. Generalist omnivores (C. auriga, C. citrinellus, C. ephippium and C. ulietensis) were the most efficient cleaners (% cleaning range: 26-40% of total biomass). Within this group, C. ephippium removed the most biomass (average of 41%) targeting algae and anemones. However, C. auriga targeted the most diverse range of epibionts, removing significant amounts of algae, sponges, tunicates, and anemones. These results suggest that foraging by butterflyfishes can substantially reduce biofouling on economically-important tropical bivalves.

  11. Hydrodynamic cavitation to prevent legionella and scaling; Hydrodynamische cavitatie voorkomt legionella en kalk

    Energy Technology Data Exchange (ETDEWEB)

    Van Baarle, D. (ed.)

    2006-03-15

    To prevent biofouling, legionella, scaling and corrosion in heat exchangers or cooling systems chemicals are added to the process and the cooling water. An alternative is the use of so-called hydrodynamic cavitation. [Dutch] Om biofouling, kalkaanslag en corrosie tegen te gaan, worden chemicalien aan proces en koelwater toegevoegd. Er is nu ook een chemicalienvrij mechanisch alternatief om legionellavorming, corrosie en kalkafzet tegen te gaan: hydrodynamische cavitatie. Door water in een vortex-stroom te leiden ontstaan er cavitatiekrachten die (legionella)bacterieen doden en CaCO{sub 3} omvormen tot filtreerbare colloiden. Doordat het in het water aanwezige kalk niet neerslaat, verbeter de prestatie van de warmtewisselaars.

  12. Bacterial colonization of metallic surfaces exposed in marine environment. Use of bacterial lipids

    International Nuclear Information System (INIS)

    Guezennec, Jean

    1986-01-01

    Addressing fouling and more particularly biofouling phenomena occurring notably on structures in marine environment, this research thesis first describes the fouling phenomenon (components, sequences of biofouling development, bio-film chemical composition). The author reports the study of the composition of the biological veil (microbiological methods, presentation of the different components), addresses the various types of lipids (bacterial markers and others). Then, after a presentation of the experimental equipment and methods (test cells, sample preparation, gas phase chromatography, hydrogenation and bromination, mass spectrometry), the author discusses the influence of different parameters such as the substrate type, speed, season, chlorination, and correlation with thermal transfer [fr

  13. Testing animal-assisted cleaning prior to transplantation in coral reef restoration.

    Science.gov (United States)

    Frias-Torres, Sarah; van de Geer, Casper

    2015-01-01

    Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment) site and the nursery (control) site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores) consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals.

  14. Testing animal-assisted cleaning prior to transplantation in coral reef restoration

    Directory of Open Access Journals (Sweden)

    Sarah Frias-Torres

    2015-09-01

    Full Text Available Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment site and the nursery (control site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals.

  15. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: Formation, structure, detachment and impact of flux change

    KAUST Repository

    Dreszer, C.; Wexler, Adam D.; Drusová , S.; Overdijk, T.; Zwijnenburg, Arie; Flemming, Hans Curt; Kruithof, Joop C.; Vrouwenvelder, Johannes S.

    2014-01-01

    Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s-1) and permeate flux (20 L m-2h-1).In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m-2h-1). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure.Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.

  16. Testing animal-assisted cleaning prior to transplantation in coral reef restoration

    Science.gov (United States)

    van de Geer, Casper

    2015-01-01

    Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment) site and the nursery (control) site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores) consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals. PMID:26468440

  17. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: Formation, structure, detachment and impact of flux change

    KAUST Repository

    Dreszer, C.

    2014-12-01

    Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s-1) and permeate flux (20 L m-2h-1).In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m-2h-1). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure.Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.

  18. Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization

    KAUST Repository

    Wang, Yiran; Fortunato, Luca; Jeong, Sanghyun; Leiknes, TorOve

    2017-01-01

    Gravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) configurations. It operates at an ultra-low pressure by gravity, requiring a minimal energy. The objective of this study was to understand the performance of GDM filtration system and characterize the biofouling formation on a flat sheet membrane. This submerged GDM reactor was operated at constant gravitational pressure in treating of two different concentrations of secondary wastewater effluent. Morphology of biofilm layer was acquired by an in-situ and on-line optical coherence tomography (OCT) scanning in a fixed position at regular intervals. The thickness and roughness calculated from OCT images were related to the variation of flux, fouling resistance and permeate quality. At the end of experiment, fouling was quantified by total organic carbon (TOC) and adenosine tri-phosphate (ATP) method. Confocal laser scanning microscopy (CLSM) was also applied for biofouling morphology observation. The biofouling formed on membrane surface was mostly removed by physical cleaning confirmed by contact angle measurement before and after cleaning. This demonstrated that fouling on the membrane under ultra-low pressure operation was highly reversible. The superiority and sustainability of GDM in both flux maintaining and long-term operation with production of high quality effluent was demonstrated.

  19. Assessing Bioinspired Topographies for their Antifouling Potential Control Using Computational Fluid Dynamics (CFD

    Directory of Open Access Journals (Sweden)

    Ling Jacky

    2018-01-01

    Full Text Available Biofouling is the accumulation of unwanted material on surfaces submerged or semi submerged over an extended period. This study investigates the antifouling performance of a new bioinspired topography design. A shark riblets inspired topography was designed with Solidworks and CFD simulations were antifouling performance. The study focuses on the fluid flow velocity, the wall shear stress and the appearance of vortices are to be noted to determine the possible locations biofouling would most probably occur. The inlet mass flow rate is 0.01 kgs-1 and a no-slip boundary condition was applied to the walls of the fluid domain. Simulations indicate that Velocity around the topography averaged at 7.213 x 10-3 ms-1. However, vortices were observed between the gaps. High wall shear stress is observed at the peak of each topography. In contrast, wall shear stress is significantly low at the bed of the topography. This suggests the potential location for the accumulation of biofouling. Results show that bioinspired antifouling topography can be improved by reducing the frequency of gaps between features. Linear surfaces on the topography should also be minimized. This increases the avenues of flow for the fluid, thus potentially increasing shear stresses with surrounding fluid leading to better antifouling performance.

  20. A tuneable switch for controlling environmental degradation of bioplastics: addition of isothiazolinone to polyhydroxyalkanoates.

    Directory of Open Access Journals (Sweden)

    Catherine Anne Woolnough

    Full Text Available Controlling the environmental degradation of polyhydroxybutyrate (PHB and polyhydroxyvalerate (P(HB-co-HV bioplastics would expand the range of their potential applications. Combining PHB and P(HB-co-HV films with the anti-fouling agent 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOI, <10% w/w restricted microbial colonisation in soil, but did not significantly affect melting temperature or the tensile strength of films. DCOI films showed reduced biofouling and postponed the onset of weight loss by up to 100 days, a 10-fold increase compared to unmodified films where the microbial coverage was significant. In addition, the rate of PHA-DCOI weight loss, post-onset, reduced by about 150%; in contrast a recorded weight loss of only 0.05% per day for P(HB-co-HV with a 10% DCOI loading was observed. This is in stark contrast to the unmodified PHB film, where a recorded weight loss of only 0.75% per day was made. The 'switch' that initiates film weight loss, and its subsequent reduced rate, depended on the DCOI loading to control biofouling. The control of biofouling and environmental degradation for these DCOI modified bioplastics increases their potential use in biodegradable applications.

  1. A novel assessment of the traction forces upon settlement of two typical marine fouling invertebrates using PDMS micropost arrays

    Directory of Open Access Journals (Sweden)

    Kang Xiao

    2018-01-01

    Full Text Available Marine biofouling poses a severe threat to maritime and aquaculture industries. To prevent the attachment of marine biofouling organisms on man-made structures, countless cost and effort was spent annually. In particular, most attention has been paid on the development of efficient and environmentally friendly fouling-resistant coatings, as well as larval settlement mechanism of several major biofouling invertebrates. In this study, polydimethylsiloxane (PDMS micropost arrays were utilized as the settlement substrata and opposite tractions were identified during early settlement of the barnacle Amphibalanus amphitrite and the bryozoan Bugula neritina. The settling A. amphitrite pushed the periphery microposts with an average traction force of 376.2 nN, while settling B. neritina pulled the periphery microposts with an average traction force of 205.9 nN. These micropost displacements are consistent with the body expansion of A. amphitrite during early post-settlement metamorphosis stage and elevation of wall epithelium of B. neritina during early pre-ancestrula stage, respectively. As such, the usage of micropost array may supplement the traditional histological approach to indicate the early settlement stages or even the initiation of larval settlement of marine fouling organisms, and could finally aid in the development of automatic monitoring platform for the real-time analysis on this complex biological process.

  2. Graphene-coated hollow fiber membrane as the cathode in anaerobic electrochemical membrane bioreactors – Effect of configuration and applied voltage on performance and membrane fouling

    KAUST Repository

    Werner, Craig M.

    2015-12-22

    Electrically conductive, graphene-coated hollow-fiber porous membranes were used as cathodes in anaerobic electrochemical membrane bioreactors (AnEMBRs) operated at different applied voltages (0.7 V and 0.9 V) using a new rectangular reactor configuration, compared to a previous tubular design (0.7 V). The onset of biofouling was delayed and minimized in rectangular reactors operated at 0.9 V, compared to those at 0.7 V due to higher rates of hydrogen production. Maximum transmembrane pressures for the rectangular reactor were only 0.10 bar (0.7 V) or 0.05 bar (0.9 V) after 56 days of operation, compared to 0.46 bar (0.7 V) for the tubular reactor after 52 days. The thickness of the membrane biofouling layer was approximately 0.4 µm for rectangular reactors and 4 µm for the tubular reactor. Higher permeate quality (TSS = 0.05 mg/L) was achieved in the rectangular AnEMBR than the tubular AnEMBR (TSS = 17 mg/L), likely due to higher current densities that minimized the accumulation of cells in suspension. These results show that the new rectangular reactor design, which had increased rates of hydrogen production, successfully delayed the onset of cathode biofouling and improved reactor performance.

  3. Graphene-coated hollow fiber membrane as the cathode in anaerobic electrochemical membrane bioreactors – Effect of configuration and applied voltage on performance and membrane fouling

    KAUST Repository

    Werner, Craig M.; Katuri, Krishna; Rao, Hari Ananda; Chen, Wei; Lai, Zhiping; Logan, Bruce E.; Amy, Gary L.; Saikaly, Pascal

    2015-01-01

    Electrically conductive, graphene-coated hollow-fiber porous membranes were used as cathodes in anaerobic electrochemical membrane bioreactors (AnEMBRs) operated at different applied voltages (0.7 V and 0.9 V) using a new rectangular reactor configuration, compared to a previous tubular design (0.7 V). The onset of biofouling was delayed and minimized in rectangular reactors operated at 0.9 V, compared to those at 0.7 V due to higher rates of hydrogen production. Maximum transmembrane pressures for the rectangular reactor were only 0.10 bar (0.7 V) or 0.05 bar (0.9 V) after 56 days of operation, compared to 0.46 bar (0.7 V) for the tubular reactor after 52 days. The thickness of the membrane biofouling layer was approximately 0.4 µm for rectangular reactors and 4 µm for the tubular reactor. Higher permeate quality (TSS = 0.05 mg/L) was achieved in the rectangular AnEMBR than the tubular AnEMBR (TSS = 17 mg/L), likely due to higher current densities that minimized the accumulation of cells in suspension. These results show that the new rectangular reactor design, which had increased rates of hydrogen production, successfully delayed the onset of cathode biofouling and improved reactor performance.

  4. Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization

    KAUST Repository

    Wang, Yiran

    2017-04-21

    Gravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) configurations. It operates at an ultra-low pressure by gravity, requiring a minimal energy. The objective of this study was to understand the performance of GDM filtration system and characterize the biofouling formation on a flat sheet membrane. This submerged GDM reactor was operated at constant gravitational pressure in treating of two different concentrations of secondary wastewater effluent. Morphology of biofilm layer was acquired by an in-situ and on-line optical coherence tomography (OCT) scanning in a fixed position at regular intervals. The thickness and roughness calculated from OCT images were related to the variation of flux, fouling resistance and permeate quality. At the end of experiment, fouling was quantified by total organic carbon (TOC) and adenosine tri-phosphate (ATP) method. Confocal laser scanning microscopy (CLSM) was also applied for biofouling morphology observation. The biofouling formed on membrane surface was mostly removed by physical cleaning confirmed by contact angle measurement before and after cleaning. This demonstrated that fouling on the membrane under ultra-low pressure operation was highly reversible. The superiority and sustainability of GDM in both flux maintaining and long-term operation with production of high quality effluent was demonstrated.

  5. The efficacy of sewage influent-isolated bacteriophages on Pseudomonas aeruginosa in a mixed-species biofilm

    KAUST Repository

    Yap, Scott

    2016-01-01

    The growth of environmentally persistent biofilms in cooling towers causes several associated problems, including microbiologically-induced corrosion (MIC) and biofouling. Current chemical control methods are not only ineffective against biofilms

  6. Chlorine Dioxide: The State of Science, Regulatory, Environmental Issues, and Case Histories

    National Research Council Canada - National Science Library

    Burton, Dennis

    2001-01-01

    The use of chlorine by electric utilities and other surface water users to inhibit biofouling and the chlorination of wastewater by POTWs to eliminate the discharge of pathogenic organisms are widespread practices...

  7. Development of Improved Membranes for ROWPU Spiral-Wound Elements

    National Research Council Canada - National Science Library

    Riley, R

    2001-01-01

    .... They are: poor lack of chemical stability to oxidants such as chlorine, high fouling rates due to membrane surface roughness and high bacterial attachment counts on the membrane surface leading to biofouling...

  8. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

    Science.gov (United States)

    Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-01-01

    Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  9. Investigation of coal combustion by-product utilization for oyster reef development in Texas bay waters

    International Nuclear Information System (INIS)

    Baker, W.B. Jr.; Ray, S.M.; Landry, A.M. Jr.

    1991-01-01

    Houston Lighting and Power Company (HL and P), Texas A and M University at Galveston and JTM Industries, Inc. initiated research in May 1988 and coordinated it with state and federal resource protection agencies to investigate the use of certain HL and P coal combustion by-products (CCBP) for enhancing and creating oyster reefs. Initial research involved determining and optimum mix design based on compressive strength, leaching potential, biofouling success, and cost. CCBP material was found to exceed compressive strength criterion (300 psi for at sign 14 days) and was not a significant leaching source. Candidate mix designs and oyster shell controls were exposed to hatchery-reared oyster larvae to determine spat setability and biofouling success. Larvae setting on CCBP substrate developed into spat and grew at a rate comparable to that for larvae on controls. Since all candidate mix designs exhibited excellent biofouling, an optimum design was chosen based on strength and material cost factors. Chemical analyses conducted to determine materials did not significantly contribute to the trace element load in oysters. Development of oyster cultch material was initiated with input from commercial 2.5 to 7.6 cm (1 to 3 inch) diameter pellets which are irregularly shaped and rough textured. These pellets greatly enhance water circulation, provide maximum setting potential for oyster larvae, and maximize the surface area to volume potential of the CCBP material

  10. Inhibition of Cariogenic Plaque Formation on Root Surface with Polydopamine-Induced-Polyethylene Glycol Coating

    Directory of Open Access Journals (Sweden)

    May Lei Mei

    2016-05-01

    Full Text Available Root caries prevention has been a challenge for clinicians due to its special anatomical location, which favors the accumulation of dental plaque. Researchers are looking for anti-biofouling material to inhibit bacterial growth on exposed root surfaces. This study aimed to develop polydopamine-induced-polyethylene glycol (PEG and to study its anti-biofouling effect against a multi-species cariogenic biofilm on the root dentine surface. Hydroxyapatite disks and human dentine blocks were divided into four groups for experiments. They received polydopamine-induced-PEG, PEG, polydopamine, or water application. Contact angle, quartz crystal microbalance, and Fourier transform infrared spectroscopy were used to study the wetting property, surface affinity, and an infrared spectrum; the results indicated that PEG was induced by polydopamine onto a hydroxyapatite disk. Salivary mucin absorption on hydroxyapatite disks with polydopamine-induced-PEG was confirmed using spectrophotometry. The growth of a multi-species cariogenic biofilm on dentine blocks with polydopamine-induced-PEG was assessed and monitored by colony-forming units, confocal laser scanning microscopy, and scanning electron microscopy. The results showed that dentine with polydopamine-induced-PEG had fewer bacteria than other groups. In conclusion, a novel polydopamine-induced-PEG coating was developed. Its anti-biofouling effect inhibited salivary mucin absorption and cariogenic biofilm formation on dentine surface and thus may be used for the prevention of root dentine caries.

  11. FOULING ORGANISMS OF BUOYS WITHIN MAKHACHKALA SEAPORT

    Directory of Open Access Journals (Sweden)

    C. N. Imachova

    2011-01-01

    Full Text Available It is investigated biofouling buoys within Makhachkala seaport. Seasonal dynamics of development of community, structure species and trophic structure is revealed. It is established vertical zonality in distribution of fouling.

  12. Underwater adhesion: The barnacle way

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.

    . Understanding of the molecular mechanisms of adhesion, that is bioadhesive bond formation and curing, is essential to develop a more rational approach in designing fouling- release coatings. Silicone biofouling release coatings have been shown...

  13. Sulfobetaine-based polymer brushes in marine environment: Is there an effect of the polymerizable group on the antifouling performance?

    NARCIS (Netherlands)

    Quintana, R.; Janczewski, D.; Vasantha, V.A.; Jana, S.; Lee, S.S.C.; Parra-Velandia, F.J.; Guo, S.; Parthiban, A.; Teo, S.L-M.; Vancso, Gyula J.

    2014-01-01

    Three different zwitterionic polymer brush coatings for marine biofouling control were prepared bysurface-initiated atom transfer radical polymerization (ATRP) of sulfobetaine-based monomers includingmethacrylamide (SBMAm), vinylbenzene (SBVB) and vinylimidazolium (SBVI). None of these brush

  14. Antifouling efficacy of a controlled depletion paint formulation with acetophenone

    Directory of Open Access Journals (Sweden)

    Sangmok Jung

    2017-12-01

    Full Text Available Biofouling is an inevitable problem that occurs continually on marine fishing vessels and other small crafts. The nature of the antifouling (AF coatings used to prevent biofouling on these small vessels is of great environmental concern. Therefore, the efficacy of a non-toxic AF candidate, acetophenone, was evaluated in preliminary laboratory assays using marine bacteria, diatom and Ulva spores. At a low concentration of 100 μg cm–2 of acetophenone, spore attachment of a green fouling alga was significantly reduced (p < 0.01. Similarly, 40% acetophenone coatings significantly inhibited diatom attachment. This new non-toxic AF agent was incorporated into controlled depletion paint (CDP. Fouling coverage (%, biomass, and fouling resistance (% were estimated. On CDP coatings made with acetophenone (40%, a significant decrease in fouling biomass was estimated (p < 0.01.

  15. Evolution and accumulation of organic foulants on hydrophobic and hydrophilic membrane surfaces in a submerged membrane bioreactor

    KAUST Repository

    Matar, Gerald

    2015-09-07

    Membrane surface modification is attracting more attention to mitigate biofouling in membrane bioreactors (MBRs). Five membranes differing in chemistry and hydrophobic/hydrophilic potential were run in parallel in a lab-scale MBR under the same conditions. Membranes were sampled after 1, 10, 20 and 30 days of MBR operation with synthetic wastewater. Subsequently, accumulated organic foulants were characterised using several chemical analytical tools. Results showed similar development of organic foulants with time, illustrating that membrane surface chemistry did not affect the selection of specific organic foulants. Multivariate analysis showed that biofilm samples clustered according to the day of sampling. The composition of organic foulants shifted from protein-like substances towards humics and polysaccharides-like substances. We propose that to control biofouling in MBRs, one should focus less on the membrane surface chemistry.

  16. Seawater-Soluble Pigments and Their Potential Use in Self-Polishing Antifouling Paints: Simulation-based Screening Tool

    DEFF Research Database (Denmark)

    Kiil, Søren; Dam-Johansen, Kim; Erik Weinell, Claus

    2002-01-01

    This work concerns the on-going development of efficient and environmentally friendly antifouling paints for biofouling control on large ocean-going ships. It is illustrated how a detailed mathematical model for a self-polishing antifouling paint exposed to seawater can be used as a product...... solubility and seawater diffusivity of dissolved pigment species have a significant influence on the polishing and leaching behaviour of a typical self-polishing paint system. The pigment size distribution, on the other hand, only has a minor influence on the paint-seawater interaction. Simulations also...... indicate that only compounds which are effective against biofouling at very low seawater concentrations are useful as active antifouling paint ingredients. The need for model verification and exploration of practical issues, subsequent a given pigment has been found of interest, is discussed. The model...

  17. Microfouling inhibitors from the Indian gorgonian Subergorgia reticulata (Ellis and Solander, 1786)

    Digital Repository Service at National Institute of Oceanography (India)

    LimnaMol, V.P.; Abhilash, K.R.; Raveendran, T.V.; Parameswaran, P.S.

    Antifouling research currently focuses on greener ways of biofouling control in view of the International Maritime Organisation (IMO) imposed regulations on toxic biocides Microfouling, the initial phase of fouling, is an important target to prevent...

  18. Role of conspecific cues and sugars in the settlement of cyprids of the barnacle, Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.

    . 4912. References Bielecki, J., Chan, B.K.K., Høeg, J.T. & Sari, A. (2009). Antennular sensory organs in cyprids of balanomorphan cirripedes: standardizing terminology using Megabalanus rosa. Biofouling 25, 203–214. Bruce,A.,Dennis...

  19. Quantitative measurement and visualization of biofilm O 2 consumption rates in membrane filtration systems

    KAUST Repository

    Prest, Emmanuelle I E C; Staal, Marc J.; Kü hl, Michael; van Loosdrecht, Mark C.M.; Vrouwenvelder, Johannes S.

    2012-01-01

    There is a strong need for techniques enabling direct assessment of biological activity of biofouling in membrane filtration systems. Here we present a new quantitative and non-destructive method for mapping O 2 dynamics in biofilms during

  20. Soft contact lens biomaterials from bioinspired phospholipid polymers.

    Science.gov (United States)

    Goda, Tatsuro; Ishihara, Kazuhiko

    2006-03-01

    Soft contact lens (SCL) biomaterials originated from the discovery of a poly(2-hydroxyethyl methacrylate) (poly[HEMA])-based hydrogel in 1960. Incorporation of hydrophilic polymers into poly(HEMA) hydrogels was performed in the 1970-1980s, which brought an increase in the equilibrium water content, leading to an enhancement of the oxygen permeability. Nowadays, the poly(HEMA)-based hydrogels have been applied in disposable SCL. At the same time, high oxygen-permeable silicone hydrogels were produced, which made it possible to continually wear SCL. Recently, numerous trials for improving the water wettability of silicone hydrogels have been performed. However, little attention has been paid to improving their anti-biofouling properties and biocompatibility. Since biomimetic phospholipid polymers possess excellent anti-biofouling properties and biocompatibility they have the potential to play a valuable role in the surface modification of the silicone hydrogel. The representative phospholipid polymers containing a 2-methacryloyloxyethyl phosphorylcholine (MPC) unit suppressed nonspecific protein adsorption, increased cell compatibility and contributed to blood compatible biomaterials. The MPC polymer coating on the silicone hydrogel improved its water wettability and biocompatibility, while maintaining high oxygen permeability compared with the original silicone hydrogel. Furthermore, the newly prepared phospholipid-type intermolecular crosslinker made it possible to synthesize a 100% phospholipid polymer hydrogel that can enhance the anti-biofouling properties and biocompatibility. In this review, the authors discuss how polymer hydrogels should be designed in order to obtain a biocompatible SCL and future perspectives.

  1. Studies on the variations in the settlement of macrofoulants in Kalpakkam coastal waters, east coast of India

    International Nuclear Information System (INIS)

    Sahu, Gouri; Prasad, M.V.R.; Satpathy, K.K.; Biswas, S.; Selvanaygam, M.

    2008-01-01

    Biofouling studies in the coastal waters of Kalpakkam were carried out with an aim to delineate the present seasonal succession and fouling potential of macrofoulants, the dominant species and their breeding period. Three series (weekly, monthly and cumulative at 30 d interval observations) of teak wood panels were exposed to coastal waters from a jetty. A marked variation was observed in the colonization of the biofoulers on the weekly panels during the present study. The highest and lowest numbers of organisms observed were 136 and 1 per sq. cm respectively. Dominance of barnacles (12.4 - 99 %) on weekly panels was found throughout the study period. A climax community of green mussels (Perna viridis) was observed in the cumulative observations. Biofouling biomass of weekly panels varied between 1 and 11 g. (100 cm) -2 , however, a steep increase in biomass was observed in 28 d (77 g. (100 cm) -2 ), 56 d (97 g. (100 cm) -2 ), 112 d (185 g. (100 cm) -2 ) and 150 d (648 g. (100 cm) -2 ) old panels. In the present study, the biomass values found to be significantly higher than those of the earlier reported values (33 and 52 g. (100 cm) -2 in 43 d and 128 d exposure respectively). Interestingly, a visible shift in the peak settlement period of green mussels (Perna viridis) was observed in the present investigation, as compared to the earlier study. (author)

  2. Characteristics of Microorganism's Fouling on Lithium Adsorbents in Okgye Harbor, Gangneung, Korea

    Science.gov (United States)

    Kim, J.; Yoon, H.; Kong, M.; Yoon, B.; Ryu, J.; Chung, K.; Kim, B.

    2013-12-01

    Marine microorganisms bring about serious ramification for nautical industry such as marine construction. Interaction of bacteria and phytoplankton causes biofouling to marine environments. To understand the marine microorganism's reaction on the inorganic surface, the experimental work carried out in pilot plant for lithium recovery field at Okgye Harbor, Gangneung, Korea through seasonal interval. To inquiry into the surface's effect for lithium recovery adsorbents by bacterial communities and phytoplankton, disk type inorganic adsorbents were immersed in same site at depth of 5 m for 7 days, 14 days and 21 days. Culturable marine bacteria were isolated and identified by 16S rRNA sequencing. Also, size and shape of marine organisms and the adsorption circumstance were investigated by SEM and CLSM (confocal laser scanning microscope). At longer exposure time of adsorbents, increase the bacterial number of individual. Vibrio sp., represented dominant species of biofouling after 21 days and marine phytoplankton increased 7 times after 7 days. Size of phytoplankton were about 50 ~ 100 μm in 0.25 mm2 area of lithium adsorbents. To increase lithium recovery rate of lithium adsorbents and to minimize the biofouling effects, it is necessary to conduct consistently field monitoring. Acknowledgments This research was supported by the national research project titled 'The Development of Technology for Extraction of Resources Dissolved in Seawater' of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Ocean and Fisheries.

  3. Characterization of Membrane Foulants in Full-scale and Lab-scale Membrane Bioreactors for Wastewater Treatment and Reuse

    KAUST Repository

    Matar, Gerald

    2015-01-01

    full-scale MBRs differed significantly from the source community (i.e. activated sludge), and random immigration of species from the source community was unlikely to shape the community structure of biofilms. Also, a core biofouling community was shared

  4. Multilayers of Fluorinated Amphiphilic Polyions for Marine Fouling Prevention

    NARCIS (Netherlands)

    Zhu, X.; Guo, S.; Janczewski, D.; Parra-Velandia, F.J.; Teo, S.L-M.; Vancso, Gyula J.

    2014-01-01

    Sequential layer-by-layer (LbL) deposition of polyelectrolytes followed by chemical cross-linking was investigated as a method to fabricate functional amphiphilic surfaces for marine biofouling prevention applications. A novel polyanion, grafted with amphiphilic perfluoroalkyl polyethylene glycol

  5. Stable isotopic analysis of Barnacle larvae and their faecal pellets to evaluate the ingested food

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Anil, A.C.

    Stable isotopes of carbon and nitrogen are useful in the evaluation of food web dynamics and have been used extensively in the feeding studies. Barnacles are dominant component of the intertidal and bio-fouling communities. Life cycle of barnacles...

  6. Development and characterization of 3D-printed feed spacers for spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber; Farhat, Nadia; Bucs, Szilard; Valladares Linares, Rodrigo; Picioreanu, Cristian; Kruithof, Joop C.; van Loosdrecht, Mark C.M.; Kidwell, James; Vrouwenvelder, Johannes S.

    2016-01-01

    suggested that the impact of spacers on hydraulics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating

  7. Use of timber in shipbuilding industry: Identification and analysis of timber from shipwrecks off Goa coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Tripati, S.; Sujatha, M.; Rao, R.V.; Rao, K.S.

    for construction of sea going ships, which could resist the action of waves, currents, marine biofouling, above all, it would bring joy and wealth. In order to locate the remains of ships, cargo and their history, maritime archaeological explorations were carried...

  8. Subsurface intakes for seawater reverse osmosis facilities: Capacity limitation, water quality improvement, and economics

    KAUST Repository

    Missimer, Thomas M.; Ghaffour, NorEddine; Dehwah, Abdullah; Rachman, Rinaldi; Maliva,, Robert G.; Amy, Gary L.

    2013-01-01

    % of bacteria, reduction in the concentrations of TOC and DOC, and virtual elimination of biopolymers and polysaccharides that cause organic biofouling of membranes. Economic analyses show that overall SWRO operating costs can be reduced by 5 to 30% by using

  9. Microbiologically Influenced Corrosion: Causative Organisms and Mechanisms

    Science.gov (United States)

    2012-01-31

    enviromental composition as a potential method for reversing microbiologically influenced corrosion, Corrosion (NAC’E) International. Houston. Texas...International fellow and associate editor for Biofouling, The Journal of Bioadhesion and Biofilm Research. J. Lee is a Materials and Corrosion Engineer

  10. INFLUENCE OF GROUNDWATER GEOCHEMISTRY ON THE LONG-TERM PERFORMANCE OF IN-SITU PERMEABLE REACTIVE BARRIERS CONTAINING ZERO-VALENT IRON

    Science.gov (United States)

    Reactive barriers that couple subsurface fluid flow with a passive chemical treatment zone are emerging, cost effective approaches for in-situ remediation of contaminated groundwater. Factors such as the build-up of surface precipitates, bio-fouling, and changes in subsurface tr...

  11. GEOCHEMISTRY OF SUBSURFACE REACTIVE BARRIERS FOR REMEDIATION OF CONTAMINATED GROUND WATER

    Science.gov (United States)

    Reactive barriers that couple subsurface fluid flow with a passive chemical treatment zone are emerging, cost effective approaches for in-situ remediation of contaminated groundwater. Factors such as the build-up of surface precipitates, bio-fouling, and changes in subsurface tr...

  12. Relaxation induced optical anisotropy during dynamic overshoot swelling of zwitterionic polymer films

    NARCIS (Netherlands)

    Ogieglo, Wojciech; de Grooth, Joris; Wormeester, Herbert; Wessling, Matthias; Nijmeijer, Dorothea C.; Benes, Nieck Edwin

    2013-01-01

    In-situ spectroscopic ellipsometry was used to investigate the swelling behavior of thin supported zwitterionic polymers based on sulfobetaine methacrylate and n-butylacrylate. This material represents an interesting class of zwitterionic polymers, with large potential in reduction of biofouling of

  13. Barnacles and their significance in biofouling

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Desai, D.V.; Khandeparker, L.; Gaonkar, C.A.

    as severely as delayed metamorphosis, which may ultimately influence juvenile and adult population dynamics in the field. The physiological condition of the cyprids is largely determined by their energy reserve (i.e. larval feeding history) and physiological... coated multiwells. As earlier hypothesized by (Yule and Walker 1987) that sugars in solution adsorb electrostatically through – OH groups to polar groups associated with the cypris temporary adhesive (CTA), the detection of AE and deposition of foot...

  14. Contact angle studies on PDMS surfaces fouled by bovine serum albumin

    CSIR Research Space (South Africa)

    Windvoel, VT

    2010-01-01

    Full Text Available Polydimethylsiloxane (PDMS) has a hydrophobic surface, forming a contact angle of around 110º with deionised water. It is due to its hydrophobic nature that the elastomer is prone to bio-fouling, such as non-specific adsorption of biomaterials like...

  15. Towards new membrane-based technologies for water treatment and reuse in the textile industry

    DEFF Research Database (Denmark)

    Petrinić, Irena; Hélix-Nielsen, Claus

    2014-01-01

    Textile wastewater represents challenging feed streams to be treated by membrane separation due to the complex composition and presence of reactive components. Here we first briefly present some characteristics of textile wastewater remediation where a key issue is (bio)fouling. We then present...

  16. Membrane technologies for water treatment and reuse in the textile industry

    DEFF Research Database (Denmark)

    Petrinić, I.; Bajraktari, Niada; Hélix-Nielsen, Claus

    2015-01-01

    technology for textile wastewater remediation. However, for all of these approaches the general issue of (bio)fouling represents a major obstacle for full-scale industrial implementation. Forward osmosis (FO) membranes have recently attracted considerable interest because the low fouling propensity of FO...

  17. Nove membranske tehnologije za obradu tekstilnih otpadnih voda i njihovu ponovnu uporabu

    DEFF Research Database (Denmark)

    Petrinić, Irena; Hélix-Nielsen, Claus

    2014-01-01

    Textile wastewater represents challenging feed streams to be treated by membrane separation due to the complex composition and presence of reactive components. Here we first briefly present some characteristics of textile wastewater remediation where a key issue is (bio)fouling. We then present...

  18. Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

    NARCIS (Netherlands)

    Natalio, F.; Andre, R.; Hartog, A.F.; Stoll, B.; Jochum, K.P.; Wever, R.; Tremel, W.

    2012-01-01

    Marine biofouling—the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls—is an expensive problem that is currently without an environmentally compatible solution1. Biofouling leads to increased hydrodynamic drag, which, in turn, causes

  19. Non-toxic, non-biocide-release antifouling coatings based on molecular structure design for marine applications

    NARCIS (Netherlands)

    Nurioglu, A.G.; Carvalho Esteves, de A.C.; With, de G.

    2015-01-01

    Marine biofouling generally refers to the undesirable accumulation of biological organisms on surfaces in contact with seawater. This natural phenomenon represents a major economic concern for marine industries, e.g. for ships and vessels, oil and wind-turbine sea-platforms, pipelines, water valves

  20. Bacterial community structure and variation in a full-scale seawater desalination plant for drinking water production

    NARCIS (Netherlands)

    Belila, A.; El-Chakhtoura, J.; Otaibi, N.; Muyzer, G.; Gonzalez-Gil, G.; Saikaly, P.E.; van Loosdrecht, M.C.M.; Vrouwenvelder, J.S.

    2016-01-01

    Microbial processes inevitably play a role in membrane-based desalination plants, mainly recognized as membrane biofouling. We assessed the bacterial community structure and diversity during different treatment steps in a full-scale seawater desalination plant producing 40,000 m3/d of drinking

  1. Natural antifouling compound production by microbes associated with marine macroorganisms — A review

    Directory of Open Access Journals (Sweden)

    Sathianeson Satheesh

    2016-05-01

    Full Text Available In the marine environment, all hard surfaces including marine macroorganims are colonized by microorganisms mainly from the surrounding environment. The microorganisms associated with marine macroorganisms offer tremendous potential for exploitation of bioactive metabolites. Biofouling is a continuous problem in marine sectors which needs huge economy for control and cleaning processes. Biotechnological way for searching natural product antifouling compounds gained momentum in recent years because of the environmental pollution associated with the use of toxic chemicals to control biofouling. While, natural product based antifoulants from marine organisms particularly sponges and corals attained significance due to their activities in field assays, collection of larger amount of organisms from the sea is not a viable one. The microorganisms associated with sponges, corals, ascidians, seaweeds and seagrasses showed strong antimicrobial and also antifouling activities. This review highlights the advances in natural product antifoulants research from microbes associated with marine organisms.

  2. Challenges for the Development of New Non-Toxic Antifouling Solutions

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Maréchal

    2009-10-01

    Full Text Available Marine biofouling is of major economic concern to all marine industries. The shipping trade is particularly alert to the development of new antifouling (AF strategies, especially green AF paint as international regulations regarding the environmental impact of the compounds actually incorporated into the formulations are becoming more and more strict. It is also recognised that vessels play an extensive role in invasive species propagation as ballast waters transport potentially threatening larvae. It is then crucial to develop new AF solutions combining advances in marine chemistry and topography, in addition to a knowledge of marine biofoulers, with respect to the marine environment. This review presents the recent research progress made in the field of new non-toxic AF solutions (new microtexturing of surfaces, foul-release coatings, and with a special emphasis on marine natural antifoulants as well as the perspectives for future research directions.

  3. A reliable sewage quality abnormal event monitoring system.

    Science.gov (United States)

    Li, Tianling; Winnel, Melissa; Lin, Hao; Panther, Jared; Liu, Chang; O'Halloran, Roger; Wang, Kewen; An, Taicheng; Wong, Po Keung; Zhang, Shanqing; Zhao, Huijun

    2017-09-15

    With closing water loop through purified recycled water, wastewater becomes a part of source water, requiring reliable wastewater quality monitoring system (WQMS) to manage wastewater source and mitigate potential health risks. However, the development of reliable WQMS is fatally constrained by severe contamination and biofouling of sensors due to the hostile analytical environment of wastewaters, especially raw sewages, that challenges the limit of existing sensing technologies. In this work, we report a technological solution to enable the development of WQMS for real-time abnormal event detection with high reliability and practicality. A vectored high flow hydrodynamic self-cleaning approach and a dual-sensor self-diagnostic concept are adopted for WQMS to effectively encounter vital sensor failing issues caused by contamination and biofouling and ensure the integrity of sensing data. The performance of the WQMS has been evaluated over a 3-year trial period at different sewage catchment sites across three Australian states. It has demonstrated that the developed WQMS is capable of continuously operating in raw sewage for a prolonged period up to 24 months without maintenance and failure, signifying the high reliability and practicality. The demonstrated WQMS capability to reliably acquire real-time wastewater quality information leaps forward the development of effective wastewater source management system. The reported self-cleaning and self-diagnostic concepts should be applicable to other online water quality monitoring systems, opening a new way to encounter the common reliability and stability issues caused by sensor contamination and biofouling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Earthworm-assisted bioremediation of petroleum hydrocarbon ...

    African Journals Online (AJOL)

    Ameh

    The use of earthworms (Eudrilus eugenia) for vermi-assisted bioremediation of petroleum hydrocarbon contaminated mechanic workshop soils ... not always result in complete neutrali- zation of pollutants (Yerushalmi et al., 2003). ..... Screening of biofouling activity in marine bacterial isolate from ship hull. Int. J. Environ. Sci.

  5. Costs and benefits to European shipping of ballast-water and hull-fouling treatment

    NARCIS (Netherlands)

    Fernandes, Jose A.; Santos, Lionel; Vance, Thomas; Fileman, Tim; Smith, David; Bishop, John D.D.; Viard, Frédérique; Queirós, Ana M.; Merino, Gorka; Buisman, Erik; Austen, Melanie C.

    2016-01-01

    Maritime transport and shipping are impacted negatively by biofouling, which can result in increased fuel consumption. Thus, costs for fouling reduction can be considered an investment to reduce fuel consumption. Anti-fouling measures also reduce the rate of introduction of non-indigenous species

  6. Antennular sensory organs in cyprids of balanomorphan cirripedes

    DEFF Research Database (Denmark)

    Bielecki, Jan; Chan, Benny K K; Høeg, Jens Thorvald

    2009-01-01

    is therefore important for understanding the events that culminate in biofouling by barnacles. There are at present no complete, standardised accounts of the structure of the cyprid antennules in thoracican barnacles, and moreover, the existing accounts vary in their use of terminology. This article describes...

  7. The greening of the coasts: review of the Perna viridis success story.

    NARCIS (Netherlands)

    Rajagopal, S.; Venugopalan, V.P.; Velde, G. van der; Jenner, H.A.

    2006-01-01

    The green mussel Perna viridis has been receiving a lot of attention from workers working in the research areas of intertidal ecology, aquaculture, pollution monitoring, biofouling, zoogeography and invasion biology. P. viridis is a remarkable species in terms of its ability to reach very high

  8. Comment on "Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds" by Savoca et al.

    NARCIS (Netherlands)

    dell'Ariccia, Gaia; Phillips, Richard A.; Franeker, van J.A.; Gaidet, Nicolas; Catrey, Paulo; Granadeiro, Jose P.; Ryan, Peter G.; Bonadonna, Franceso

    2017-01-01

    In their recent paper, Savoca and collaborators (2016) showed that plastic debris in the ocean may acquire a dimethyl sulfide (DMS) signature from biofouling developing on their surface. According to them, DMS emission may represent an olfactory trap for foraging seabirds, which explains patterns of

  9. Tight ceramic UF membrane as RO pre-treatment: The role of electrostatic interactions on phosphate rejection

    NARCIS (Netherlands)

    Shang, R.; Verliefde, A.R.D.; Hu, J.; Zeng, Z; Lu, L.; Lu, L.; Kemperman, Antonius J.B.; Deng, H.; Nijmeijer, Dorothea C.; Heijman, S.G.J.; Rietveld, L.C.

    2014-01-01

    Phosphate limitation has been reported as an effective approach to inhibit biofouling in reverse osmosis (RO) systems for water purification. The rejection of dissolved phosphate by negatively charged TiO2 tight ultrafiltration (UF) membranes (1 kDa and 3 kDa) was observed. These membranes can

  10. Artificial cilia for microparticle manipulation and anti-fouling

    NARCIS (Netherlands)

    Zhang, S.; Wang, Y.; den Toonder, J.M.J.

    2016-01-01

    The (bio-)fouling of surfaces submerged in liquid forms serious a problem for many applications. One inspiration to address this issue is the use of cilia which, in nature, are found very effective in particle manipulation. We have fabricated magnetically actuated artificial cilia (MAAC) using a

  11. In situ glass antifouling using Pt nanoparticle coating for periodic electrolysis of seawater

    Science.gov (United States)

    Xue, Yuxi; Zhao, Jin; Qiu, Ri; Zheng, Jiyong; Lin, Cunguo; Ma, Bojiang; Wang, Peng

    2015-12-01

    In situ electrochemical chlorination is a promising way to prohibit the biofouling on glass used for optical devices in seawater. To make this approach practical, a conductive glass should have low overpotential to generate Cl2, so that the electrical energy consumption, a critical issue for field application, will be low. Moreover, a long sustainability should also be taken into consideration from the application perspective. Following these criteria, we propose Pt/ITO surface to electrochemically generate Cl2, which immunizes biofouling for glass substrate. In this report, firstly, Pt nanoparticle/ITO is prepared via an electrodeposition approach. Secondly, electrocatalysis capability of Pt/ITO is elucidated, which shows the catalysis for Cl2 generation from NaCl solution and seawater has been sparked with Pt on the surface. Also, Pt/ITO is more sustainable and efficient than the bare ITO in natural seawater. Thirdly, the antifouling property is evaluated taking diatom as the target organism. Electrochemical chlorination on Pt/ITO can efficiently prevent the glass from fouling.

  12. Nanotechnology applications to desalination : a report for the joint water reuse & desalination task force.

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Patrick Vane; Mayer, Tom; Cygan, Randall Timothy

    2011-01-01

    Nanomaterials and nanotechnology methods have been an integral part of international research over the past decade. Because many traditional water treatment technologies (e.g. membrane filtration, biofouling, scale inhibition, etc.) depend on nanoscale processes, it is reasonable to expect one outcome of nanotechnology research to be better, nano-engineered water treatment approaches. The most immediate, and possibly greatest, impact of nanotechnology on desalination methods will likely be the development of membranes engineered at the near-molecular level. Aquaporin proteins that channel water across cell membranes with very low energy inputs point to the potential for dramatically improved performance. Aquaporin-laced polymer membranes and aquaporin-mimicking carbon nanotubes and metal oxide membranes developed in the lab support this. A critical limitation to widespread use of nanoengineered desalination membranes will be their scalability to industrial fabrication processes. Subsequent, long-term improvements in nanoengineered membranes may result in self-healing membranes that ideally are (1) more resistant to biofouling, (2) have biocidal properties, and/or (3) selectively target trace contaminants.

  13. Evaluation of the natural product antifoulant, zosteric acid, for preventing the attachment of quagga mussels--a preliminary study.

    Science.gov (United States)

    Ram, Jeffrey L; Purohit, Sonal; Newby, Bi-Min Zhang; Cutright, Teresa J

    2012-01-01

    The effectiveness of zosteric acid, a natural antifoulant from the marine seagrass Zostera marina, in preventing the attachment of quagga mussels, a biofouling bivalve, was investigated. Animals were exposed to water containing zosteric acid ranging from 0 to 1000 ppm, and their attachment to the container glass walls was tracked with time. 500 ppm zosteric acid was not effective at detaching animals that had already attached, but was able to prevent the attachment of most unattached animals for two days. The anti-fouling effect increased with higher concentration. Low concentrations (250 ppm and below) were not effective at preventing attachment; however, 1000 ppm zosteric acid prevented attachment of mussels for the first three days of zosteric acid exposure, and only 20% of the mussels were attached by day 4. In contrast, animals in control (no zosteric acid) solutions began to attach within one day. In conclusion, zosteric acid is an effective natural product deterrent of attachment of a biofouling bivalve.

  14. Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces.

    Science.gov (United States)

    Secker, T J; Pinchin, H E; Hervé, R C; Keevil, C W

    2015-01-01

    Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.

  15. Titanium condenser tubes--problems and their solutions for wider application to large surface condensers

    Energy Technology Data Exchange (ETDEWEB)

    Sato, S; Sugiyama, Y; Nagata, K; Namba, K; Shimono, M

    1978-01-01

    To meet the demand for high reliability condensers for thermal and nuclear power plants, especially for PWR plants, the condensers installed entirely with titanium tubes have been investigated and used. Some difficulties from conventional copper alloy tubes exist. Further investigations are necessary on three items: (1) tube vibration; (2) joining tubes to tube plate; (3) fouling (bio-fouling) control. Literature survey on the tube vibration suggests that the probability of tube vibration due to decreased stiffness of titanium tubes in comparison with conventional copper alloy tubes can be decreased by designing the proper span length between supports. Experiments on seal welding of tubes to a tube plate have successfully proved that pulsed TIG arc welding is applicable to get reliable and strong joints, even on site, by suitable countermeasures. Experiments on the fouling (bio-fouling) of titanium tubes in marine application reveal that the increased fouling of titanium tubes could be controlled by proper application of sponge ball cleaning.

  16. Utilization of artificial recharged effluent as makeup water for industrial cooling system: corrosion and scaling.

    Science.gov (United States)

    Wei, Liangliang; Qin, Kena; Zhao, Qingliang; Noguera, Daniel R; Xin, Ming; Liu, Chengcai; Keene, Natalie; Wang, Kun; Cui, Fuyi

    2016-01-01

    The secondary effluent from wastewater treatment plants was reused for industrial cooling water after pre-treatment with a laboratory-scale soil aquifer treatment (SAT) system. Up to a 95.3% removal efficiency for suspended solids (SS), 51.4% for chemical oxygen demand (COD), 32.1% for Cl(-) and 30.0% SO4(2-) were observed for the recharged secondary effluent after the SAT operation, which is essential for controlling scaling and corrosion during the cooling process. As compared to the secondary effluent, the reuse of the 1.5 m depth SAT effluent decreased the corrosion by 75.0%, in addition to a 55.1% decline of the scales/biofouling formation (with a compacted structure). The experimental results can satisfy the Chinese criterion of Design Criterion of the Industrial Circulating Cooling Water Treatment (GB 50050-95), and was more efficient than tertiary effluent which coagulated with ferric chloride. In addition, chemical structure of the scales/biofouling obtained from the cooling system was analyzed.

  17. Propagule pressure determines recruitment from a commercial shipping pier.

    Science.gov (United States)

    Hedge, Luke H; Johnston, Emma L

    2012-01-01

    Artificial structures associated with shipping and boating activities provide habitats for a diverse suite of non-indigenous marine species. Little is known about the proportion of invader success in nearby waters that is attributable to these structures. Areas close to piles, wharves and piers are likely to be exposed to increasing levels of propagule pressure, enhancing the recruitment of non-indigenous species. Recruitment of non-indigenous and native marine biofouling taxa were evaluated at different distances from a large commercial shipping pier. Since artificial structures also represent a desirable habitat for fish, how predation on marine invertebrates influences the establishment of non-indigenous and native species was also evaluated. The colonisation of several non-indigenous marine species declined rapidly with distance from the structure. Little evidence was found to suggest that predators have much influence on the colonisation success of marine sessile invertebrate species, non-indigenous or otherwise. It is suggested that propagule pressure, not predation, more strongly predicts establishment success in these biofouling assemblages.

  18. Antifouling and antibacterial polyketides from marine gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023.

    Science.gov (United States)

    Bao, Jie; Sun, Yu-Lin; Zhang, Xiao-Yong; Han, Zhuang; Gao, Hai-Chun; He, Fei; Qian, Pei-Yuan; Qi, Shu-Hua

    2013-04-01

    Two new polyketides, 6,8,5'6'-tetrahydroxy-3'-methylflavone (1) and paecilin C (2), together with six known analogs secalonic acid D (3), secalonic acid B (4) penicillixanthone A (5), emodin (6), citreorosein (7) and isorhodoptilometrin (8) were obtained from a broth of gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023. Compounds 1 and 6-8 had significant antifouling activity against Balanus amphitrite larvae settlement with EC50 values of 6.7, 6.1, 17.9 and 13.7 μg ml(-1), respectively, and 3-5 showed medium antibacterial activity against four tested bacterial strains. This was the first report of antibacterial activity of 3-5 against marine bacteria and antifouling activity of 6-8 against marine biofouling organism's larvae. The results indicated that gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023 strain could produce antifouling and antibacterial compounds that might aid the host gorgonian coral in protection against marine pathogen bacteria, biofouling organisms and other intruders.

  19. Succession and physiological health of freshwater microalgal fouling in a Tasmanian hydropower canal.

    Science.gov (United States)

    Perkins, Kathryn J; Andrewartha, Jessica M; McMinn, Andrew; Cook, Suellen S; Hallegraeff, Gustaaf M

    2010-08-01

    Freshwater microalgal biofouling in hydropower canals in Tarraleah, Tasmania, is dominated by a single diatom species, Gomphonema tarraleahae. The microfouling community is under investigation with the aim of reducing its impact on electricity generation. Species succession was investigated using removable glass slides. Fouled slides were examined microscopically and for chlorophyll a biomass. Chl a biomass increased steeply after 8 weeks (0.09-0.87 mg m(-2)), but increased much earlier on slides surrounded by a biofouled inoculum. Succession began with low profile diatoms such as Tabellaria flocculosa, progressing to stalked diatoms such as Gomphonema spp. and Cymbella aspera. Few chlorophytes and no filamentous algae were present. Pulse amplitude modulated fluorometry was used to measure the physiological health of fouling on the canal wall. Maximum quantum yield (F(v)/F(m)) measurements were consistently <0.18, indicating that the fouling mat consisted of dead or dying algae. The succession and physiological health of cells in the fouling community has broad implications for mitigation techniques used.

  20. Reaction rate estimation of controlled-release antifouling paint binders: Rosin-based systems

    DEFF Research Database (Denmark)

    Meseguer Yebra, Diego; Kiil, Søren; Dam-Johansen, Kim

    2005-01-01

    Biofouling on ship hulls is prevented by the use of antifouling (A/F) paints. Typically, sea water soluble rosin or rosin-derivatives are used as the primary means of adjusting the polishing rate of the current chemically active self-polishing paint systems to a suitable value. Previous studies h...

  1. Biofilms on Indwelling Urologic Devices: Microbes and Antimicrobial ...

    African Journals Online (AJOL)

    hanumantp

    Results: Both single and multi‑species BFs were formed on catheters, whereas mono‑bacterial BFs were exclusive on stents. Predominant organisms were. Pseudomonas ..... of biofouling until the colonized device is removed. Even after removal of a BF colonized-catheter, persistent organisms may re-colonize on the new ...

  2. Polymer-based and Polymer-templated Nanostructured Thermoelectric Devices

    Science.gov (United States)

    2014-07-23

    reduction of bio-fouling,32 finger-print resistant surfaces for flat- panel displays, cell-phones and sunglasses,33 drag reduction,34 developing...Broad Band Absorption Enhancement. Nano Lett 10, 3041-3046, doi:Doi 10.1021/Nl101510q (2010). 72 Baca, A. J. et al. Compact monocrystalline silicon

  3. Tight ceramic UF membrane as RO pre-treatment: the role of electrostatic interactions on phosphate rejection.

    Science.gov (United States)

    Shang, Ran; Verliefde, Arne R D; Hu, Jingyi; Zeng, Zheyi; Lu, Jie; Kemperman, Antoine J B; Deng, Huiping; Nijmeijer, Kitty; Heijman, Sebastiaan G J; Rietveld, Luuk C

    2014-01-01

    Phosphate limitation has been reported as an effective approach to inhibit biofouling in reverse osmosis (RO) systems for water purification. The rejection of dissolved phosphate by negatively charged TiO2 tight ultrafiltration (UF) membranes (1 kDa and 3 kDa) was observed. These membranes can potentially be adopted as an effective process for RO pre-treatment in order to constrain biofouling by phosphate limitation. This paper focuses on electrostatic interactions during tight UF filtration. Despite the larger pore size, the 3 kDa ceramic membrane exhibited greater phosphate rejection than the 1 kDa membrane, because the 3 kDa membrane has a greater negative surface charge and thus greater electrostatic repulsion against phosphate. The increase of pH from 6 to 8.5 led to a substantial increase in phosphate rejection by both membranes due to increased electrostatic repulsion. At pH 8.5, the maximum phosphate rejections achieved by the 1 kDa and 3 kDa membrane were 75% and 86%, respectively. A Debye ratio (ratio of the Debye length to the pore radius) is introduced in order to evaluate double layer overlapping in tight UF membranes. Threshold Debye ratios were determined as 2 and 1 for the 1 kDa and 3 kDa membranes, respectively. A Debye ratio below the threshold Debye ratio leads to dramatically decreased phosphate rejection by tight UF membranes. The phosphate rejection by the tight UF, in combination with chemical phosphate removal by coagulation, might accomplish phosphate-limited conditions for biological growth and thus prevent biofouling in the RO systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Microbial community analysis of fouled reverse osmosis membranes used in water recycling

    KAUST Repository

    Ayache, C.; Manes, Carmem Lara De O; Pidou, Marc; Croue, Jean-Philippe; Gernjak, Wolfgang

    2013-01-01

    Biofouling on RO membranes has major cost implications in water reclamation. In this study membranes and water samples were collected from a RO pilot-plant operated on two sites to study the differences in microbial communities in order to develop a better understanding of the biofouling. For the two sites studied, the examination of the front membrane of the first stage and the tail membrane of the second stage of the RO train using 16S rRNA gene-based molecular technique showed that bacteria were similar on both stages and no significant effect of the membrane location within the RO train on the biofilm development could be discerned. However, the comparison of the identified bacteria from membrane samples between the two sites showed that each site is specific, leading to a different composition of microbial communities. The different nutrient concentrations in the RO feed water due to the different biological pre-treatments are one potential explanation for the observed differences in the microbial communities. Seasonal variations also play a major role in the development of microbial communities as shown by the significant differences observed between the communities measured in the samples in winter and summer on the second site. The results did not show similarity between the species identified on the RO membranes and in the feed water. Hence, the relationship of microbial community between the water generated during the pre-treatment process and RO membranes is not obvious. From this study, results showed that there is an actual need to investigate the development of microbial communities on membrane surface in real conditions in order to suggest tailored solutions for biofouling control and removal. © 2013 Elsevier Ltd.

  5. Mini-review: novel non-destructivein situbiofilm characterization techniques in membrane systems

    KAUST Repository

    Valladares Linares, Rodrigo; Fortunato, Luca; Farhat, Nadia; Bucs, Szilard; Staal, M.; Fridjonsson, E.O.; Johns, M.L.; Vrouwenvelder, Johannes S.; Leiknes, TorOve

    2016-01-01

    Membrane systems are commonly used in the water industry to produce potable water and for advanced wastewater treatment. One of the major drawbacks of membrane systems is biofilm formation (biofouling), which results in an unacceptable decline in membrane performance. Three novel in situ biofouling characterization techniques were assessed: (i) optical coherence tomography (OCT), (ii) planar optodes, and (iii) nuclear magnetic resonance (NMR). The first two techniques were assessed using a biofilm grown on the surface of nanofiltration (NF) membranes using a transparent membrane fouling simulator that accurately simulates spiral wound modules, modified for in situ biofilm imaging. For the NMR study, a spiral wound reverse osmosis membrane module was used. Results show that these techniques can provide information to reconstruct the biofilm accurately, either with 2-D (OCT, planar optodes and NMR), or 3-D (OCT and NMR) scans. These non-destructive tools can elucidate the interaction of hydrodynamics and mass transport on biofilm accumulation in membrane systems. Oxygen distribution in the biofilm can be mapped and linked to water flow and substrate characteristics; insights on the effect of crossflow velocity, flow stagnation, and feed spacer presence can be obtained, and in situ information on biofilm structure, thickness, and spatial distribution can be quantitatively assessed. The combination of these novel non-destructive in situ biofilm characterization techniques can provide real-time observation of biofilm formation at the mesoscale. The information obtained with these tools could potentially be used for further improvement in the design of membrane systems and operational parameters to reduce impact of biofouling on membrane performance. © 2016 Balaban Desalination Publications. All rights reserved.

  6. Mini-review: novel non-destructivein situbiofilm characterization techniques in membrane systems

    KAUST Repository

    Valladares Linares, R.

    2016-05-12

    Membrane systems are commonly used in the water industry to produce potable water and for advanced wastewater treatment. One of the major drawbacks of membrane systems is biofilm formation (biofouling), which results in an unacceptable decline in membrane performance. Three novel in situ biofouling characterization techniques were assessed: (i) optical coherence tomography (OCT), (ii) planar optodes, and (iii) nuclear magnetic resonance (NMR). The first two techniques were assessed using a biofilm grown on the surface of nanofiltration (NF) membranes using a transparent membrane fouling simulator that accurately simulates spiral wound modules, modified for in situ biofilm imaging. For the NMR study, a spiral wound reverse osmosis membrane module was used. Results show that these techniques can provide information to reconstruct the biofilm accurately, either with 2-D (OCT, planar optodes and NMR), or 3-D (OCT and NMR) scans. These non-destructive tools can elucidate the interaction of hydrodynamics and mass transport on biofilm accumulation in membrane systems. Oxygen distribution in the biofilm can be mapped and linked to water flow and substrate characteristics; insights on the effect of crossflow velocity, flow stagnation, and feed spacer presence can be obtained, and in situ information on biofilm structure, thickness, and spatial distribution can be quantitatively assessed. The combination of these novel non-destructive in situ biofilm characterization techniques can provide real-time observation of biofilm formation at the mesoscale. The information obtained with these tools could potentially be used for further improvement in the design of membrane systems and operational parameters to reduce impact of biofouling on membrane performance. © 2016 Balaban Desalination Publications. All rights reserved.

  7. Microbial community analysis of fouled reverse osmosis membranes used in water recycling

    KAUST Repository

    Ayache, C.

    2013-06-01

    Biofouling on RO membranes has major cost implications in water reclamation. In this study membranes and water samples were collected from a RO pilot-plant operated on two sites to study the differences in microbial communities in order to develop a better understanding of the biofouling. For the two sites studied, the examination of the front membrane of the first stage and the tail membrane of the second stage of the RO train using 16S rRNA gene-based molecular technique showed that bacteria were similar on both stages and no significant effect of the membrane location within the RO train on the biofilm development could be discerned. However, the comparison of the identified bacteria from membrane samples between the two sites showed that each site is specific, leading to a different composition of microbial communities. The different nutrient concentrations in the RO feed water due to the different biological pre-treatments are one potential explanation for the observed differences in the microbial communities. Seasonal variations also play a major role in the development of microbial communities as shown by the significant differences observed between the communities measured in the samples in winter and summer on the second site. The results did not show similarity between the species identified on the RO membranes and in the feed water. Hence, the relationship of microbial community between the water generated during the pre-treatment process and RO membranes is not obvious. From this study, results showed that there is an actual need to investigate the development of microbial communities on membrane surface in real conditions in order to suggest tailored solutions for biofouling control and removal. © 2013 Elsevier Ltd.

  8. Determination of uptake kinetics (sampling rates) by lipid-containing semipermeable membrane devices (SPMDs) for polycyclic aromatic hydrocarbons (PAHs) in water

    Science.gov (United States)

    Huckins, J.N.; Petty, J.D.; Orazio, C.E.; Lebo, J.A.; Clark, R.C.; Gibson, V.L.; Gala, W.R.; Echols, K.R.

    1999-01-01

    The use of lipid-containing semipermeable membrane devices (SPMDs) is becoming commonplace, but very little sampling rate data are available for the estimation of ambient contaminant concentrations from analyte levels in exposed SPMDs. We determined the aqueous sampling rates (R(s)s; expressed as effective volumes of water extracted daily) of the standard (commercially available design) 1-g triolein SPMD for 15 of the priority pollutant (PP) polycyclic aromatic hydrocarbons (PAHs) at multiple temperatures and concentrations. Under the experimental conditions of this study, recovery- corrected R(s) values for PP PAHs ranged from ???1.0 to 8.0 L/d. These values would be expected to be influenced by significant changes (relative to this study) in water temperature, degree of biofouling, and current velocity- turbulence. Included in this paper is a discussion of the effects of temperature and octanol-water partition coefficient (K(ow)); the impacts of biofouling and hydrodynamics are reported separately. Overall, SPMDs responded proportionally to aqueous PAH concentrations; i.e., SPMD R(s) values and SPMD-water concentration factors were independent of aqueous concentrations. Temperature effects (10, 18, and 26 ??C) on Rs values appeared to be complex but were relatively small.The use of lipid-containing semipermeable membrane devices (SPMDs) is becoming commonplace, but very little sampling rate data are available for the estimation of ambient contaminant concentrations from analyte levels in exposed SPMDs. We determined the aqueous sampling rates (Rss; expressed as effective volumes of water extracted daily) of the standard (commercially available design) 1-g triolein SPMD for 15 of the priority pollutant (PP) polycyclic aromatic hydrocarbons (PAHs) at multiple temperatures and concentrations. Under the experimental conditions of this study, recovery-corrected Rs values for PP PAHs ranged from ???1.0 to 8.0 L/d. These values would be expected to be influenced by

  9. Progress Report Abstracts. Oceanic Biology Program.

    Science.gov (United States)

    1982-12-01

    consists of phototubes looking upward and downward, can be placed from subsurface to 200 m depth. It is connected to the laboratory via a hard wire link...Zelver, N., Dobb, D. E. and Nelson, C. R., "Influence of Bio- fouling and Biofouling Control Techniques on Corrosion of Copper- Nikel Tubes

  10. A passive apparatus for controlled-flux delivery of biocides: hydrogen peroxide as an example

    DEFF Research Database (Denmark)

    Olsen, Stefan Møller; Pedersen, L.T.; Dam-Johansen, Kim

    2010-01-01

    A new test method has been developed to estimate the required release rate of hydrogen peroxide (H2O2) to prevent marine biofouling. The technique exploits a well-defined concentration gradient of biocide across a cellulose acetate membrane. A controlled flux of H2O2, an environmentally friendly ...

  11. Biolog for the determination of diversity in microbial communities

    African Journals Online (AJOL)

    drinie

    2002-01-01

    Jan 1, 2002 ... be related to the functional diversity of the species present in the community. ... The hypothesis is that the more substrates utilised, the higher the diversity, due to the collective action of individual species. Any one organism will not necessarily utilise all the ..... biofouling control in industrial water systems.

  12. Establishment of a taxonomic and molecular reference collection to support the identification of species regulated by the Western Australian Prevention List for Introduced Marine Pests

    DEFF Research Database (Denmark)

    Dias, Joana P.; Fotedar, Seema; Muenoz, Julieta

    2017-01-01

    in IMP recognition in Australia. The reference collection is also useful in supporting the development of a variety of DNA-based detection strategies such as real-time PCR and metabarcoding of complex environmental samples (e.g. biofouling communities). The Prevention List is under regular review...... available to the biosecurity management community worldwide...

  13. The effect of environmental parameters on contaminant uptake By a ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    birds (Bedford and Zabik, 1973), benthic species. (Bedford et Zabik, 1973), or zooplankton (Leversee,. 1983) as ... The use of sessile species such as clams and mussels provides a time-integrated sample at one ... biofouling and a slow equilibrium rate between the polymer film and the water column limit its application as a ...

  14. Vessel Biofouling Prevention and Management Options Report

    Science.gov (United States)

    2015-03-01

    microorganism -containing biofilm (slime layer) which occurs on a marine surface under the right conditions. Biofilm growth can progress to a point where... biodegradable components, or non-biocidal alternatives; vessels that reside or operate >30 days in copper impaired ports or harbors shall consider alternatives...except for nontoxic, biodegradable types) or chemicals in the water is prohibited, as would be the creation of a cloud or plume generated by paint

  15. Biofouling of marbles by oxygenic photosynthetic microorganisms.

    Science.gov (United States)

    Karaca, Zeki; Öztürk, Ayten; Çolak, Emel

    2015-08-01

    Phototrophic microorganisms disfigure the surfaces of different types of stone. Stone structure is damaged by the activity of photoautotrophic and other microorganisms. However, to date few, investigations have been undertaken into the relationship between microorganisms and the properties of different types of marble. In this study, biological activity of photoautotrophic microorganisms on three types of marble (Yatagan White, Giallo Anticato and Afyon White) was investigated under laboratory conditions over a short period of time. The three types of marble supported the growth of phototrophic microbial communities on their outer and inner layers, turning their original colour from white to a yellowish green colour. The porosity of the marble types facilitated filamentous microbial growth in the presence of water. Scanning electron microscope analysis revealed the accumulation of aggregates such as small spherical, fibrillar, calcified globular bodies on the inner surfaces of the marbles. This suggests that the microscopic characteristics of particular marble types may stimulate the growth of certain types of microorganisms.

  16. Nanostructured Block Copolymer Coatings for Biofouling Inhibition

    Science.gov (United States)

    2015-06-30

    nm) High resolution vibrational sensitive images Figure 7 - The instrument provides best-in-world performance. The images are of a boron nitride...2 patents pending, publications and some trade secrets. The pure biocide has been tested by independent labs for toxicity to various mammals and...cash investments in Sylleta, which continue. In Figure 8 are the data on the toxicity of the active ingredient (biocide), which is surface tethered in

  17. Environmentally benign sol-gel antifouling and foul-releasing coatings.

    Science.gov (United States)

    Detty, Michael R; Ciriminna, Rosaria; Bright, Frank V; Pagliaro, Mario

    2014-02-18

    Biofouling on ships and boats, characterized by aquatic bacteria and small organisms attaching to the hull, is an important global issue, since over 80000 tons of antifouling paint is used annually. This biofilm, which can form in as little as 48 hours depending on water temperature, increases drag on watercraft, which greatly reduces their fuel efficiency. In addition, biofouling can lead to microbially induced corrosion (MIC) due to H2S formed by the bacteria, especially sulfate-reducing bacteria. When the International Maritime Organization (IMO) international convention banned the use of effective but environmentally damaging coatings containing tributyl tin in 2008, the development of clean and effective antifouling systems became more important than ever. New nonbiocidal coatings are now in high demand. Scientists have developed new polymers, materials, and biocides, including new elastomeric coatings that they have obtained by improving the original silicone (polydimethylsiloxane) formulation patented in 1975. However, the high cost of silicones, especially of fluoropolymer-modified silicones, has generally prevented their large-scale diffusion. In 2009, traditional antifouling coatings using cuprous oxide formulated in copolymer paints still represented 95% of the global market volume of anti-fouling paints. The sol-gel nanochemistry approach to functional materials has emerged as an attractive candidate for creating low fouling surfaces due to the unique structure and properties of silica-based coatings and of hybrid inorganic-organic silicas in particular. Sol-gel formulations easily bind to all types of surfaces, such as steel, fiberglass, aluminum, and wood. In addition, they can cure at room temperature and form thin glassy coatings that are markedly different from thick silicone elastomeric foul-releasing coatings. Good to excellent performance against biofouling, low cure temperatures, enhanced and prolonged chemical and physical stability, ease of

  18. Development of antifouling of electrochemical solid-state dissolved oxygen sensors based on nanostructured Cu0.4Ru3.4O7 + RuO2 sensing electrodes

    International Nuclear Information System (INIS)

    Zhuiykov, Serge; Kalantar-zadeh, Kourosh

    2012-01-01

    Tailoring nanostructured sensing electrode materials to high antifouling resistance has been one of the main priorities of the development of water quality sensors in the 21st century. Nanostructured Cu 0.4 Ru 3.4 O 7 + RuO 2 -SEs have been developed to address the bio-fouling problem. The change in Cu 0.4 Ru 3.4 O 7 + RuO 2 structural development being promoted by advances in nano- and micro-scale pattering. Nanostructured Cu 0.4 Ru 3.4 O 7 + RuO 2 -SEs with different mol% of Cu 2 O were screen-printed on alumina sensor substrates and were consequently subjected to a 3-month field trial at the Water Treatment Plant. Their structural and electrochemical properties before and after the experiment were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical cyclic voltammerty (CV) techniques. The relationship between dissolved oxygen (DO) and the sensor's potential difference was found to be relatively linear, with the maximum sensitivity of −46 mV per decade being achieved at 20 mol% Cu 2 O at 7.27 pH. Moreover, a 3-month field trial in the sewerage environment has shown that Cu 0.4 Ru 3.4 O 7 + RuO 2 -SE with 20 mol% of Cu 2 O possesses much higher defences against bio-fouling than the same SE with only 10 mol% of Cu 2 O. The super-hydrophobic property of the developed Cu 0.4 Ru 3.4 O 7 + RuO 2 complex oxide has been considered as one of the essential pre-requisites for high antifouling resistance. Multiple antifouling defence strategies from biomimetic to bio-inspired must be incorporated in further development of nanostructured oxide SE to solve problems of bio-fouling on the sensor's SE.

  19. Contribution of assimilable organic carbon to biological fouling in seawater reverse osmosis membrane treatment.

    Science.gov (United States)

    Weinrich, Lauren; LeChevallier, Mark; Haas, Charles N

    2016-09-15

    Biological fouling occurs on RO membranes when bacteria and nutrients are present in conditions that are conducive to growth and proliferation of the bacteria. Controlling microbial growth on the membranes is typically limited to biocide application (i.e., disinfectants) in seawater RO plants. However, biological growth and subsequent fouling has not been well-managed. Pretreatment has not been focused on nutrient limitation. This project used a biological assay, the assimilable organic carbon (AOC) test to evaluate pretreatment effects on the nutrient supply. The AOC test provided a useful surrogate measurement for the biodegradability or biofouling potential of RO feed water. Biofouling observed in controlled conditions at the bench- and pilot-scale resulted in statistically significant correlations between AOC and the operational effects caused by biofouling. Membrane fouling rates are observed through operational changes over time such as increased differential pressure between the membrane feed and concentrate locations and decreased permeate flux through the membrane. In full scale plants there were strong correlations when AOC was used as a predictor variable for increased differential pressure (0.28-0.55 bar from September-December 2012) and decreased specific flux (1.40 L per hour/(m(2) · bar)). Increased differential pressure was associated with RO membrane biological fouling when the median AOC was 50 μg/L during pilot testing. Conditions were also evaluated at the bench-scale using a flat sheet RO membrane. In a comparison test using 30 and 1000 μg/L AOC, fouling was detected on more portions of the membrane when AOC was higher. Biofilm and bacterial deposits were apparent from scanning electron microscope imaging and biomass measurements using ATP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Carapace surface architecture facilitates camouflage of the decorator crab Tiarinia cornigera.

    Science.gov (United States)

    Sanka, Immanuel; Suyono, Eko Agus; Rivero-Müller, Adolfo; Alam, Parvez

    2016-09-01

    This paper elucidates the unique setal morphology of the decorator crab Tiarinia cornigera, and further presents evidence to that setal morphology promotes micro-organism nucleation and adhesion. The carapace of this crab is covered by clusters of setae, each comprising a hollow acicular stem that is enveloped by a haystack-like structure. Using computational fluid dynamics, we find that these setae are responsible for manipulating water flow over the carapace surface. Micro-organisms in the sea water, nest in areas of flow stagnation and as a result, nucleate to and biofoul the setae by means of chemical adhesion. Attached micro-organisms secrete extracellular polymeric substances, which we deduce must also provide an additional element of chemical adhesion to mechanically interlocked mesoscopic and macroscopic biomatter. By coupling physical and chemical methods for adhesion, T. cornigera is able to hierarchically decorate its carapace. Our paper brings to light the unique decorator crab carapace morphology of T. cornigera; and furthermore evidences its function in micro-organism nucleation and adhesion. We show how this special carapace morphology directs and guides water flow to form nesting regions of water stagnation where micro-organisms can nucleate and adhere. In the literature, decorator crab carapaces are presumed to be able to mechanically interlock biomatter as camouflage using hook-like setal outgrowths. T. cornigera contrarily exhibits clusters of hay-stack like structures. By encouraging micro-organism adhesion to the carapace setae, T. cornigera is able to effectively attach biomatter using both chemical and physical principles of adhesion. T. cornigera essentially has a super-biofouling carapace surface, for at least micro-organisms. Our work will have an impact on researchers interested in biofouling, adhesion, biomedical and purification filter systems, and in the development of novel biomimetic surfaces with tailored properties. Copyright

  1. Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive compound through alteration of EPS and epiphytic bacteria

    Directory of Open Access Journals (Sweden)

    Claudia D. Infante

    2018-05-01

    Full Text Available Background: Marine ecosystems contain benthic microalgae and bacterial species that are capable of secreting extracellular polymeric substances (EPS, suggesting that settlement of these microorganisms can occur on submerged surfaces, a key part of the first stage of biofouling. Currently, anti-fouling treatments that help control this phenomenon involve the use of biocides or antifouling paints that contain heavy metals, which over a long period of exposure can spread to the environment. The bacterium Alteromonas sp. Ni1-LEM has an inhibitory effect on the adhesion of Nitzschia ovalis, an abundant diatom found on submerged surfaces. Results: We evaluated the effect of the bioactive compound secreted by this bacterium on the EPS of biofilms and associated epiphytic bacteria. Three methods of EPS extraction were evaluated to determine the most appropriate and efficient methodology based on the presence of soluble EPS and the total protein and carbohydrate concentrations. Microalgae were cultured with the bacterial compound to evaluate its effect on EPS secretion and variations in its protein and carbohydrate concentrations. An effect of the bacterial supernatant on EPS was observed by assessing biofilm formation and changes in the concentration of proteins and carbohydrates present in the biofilm. Conclusions: These results indicate that a possible mechanism for regulating biofouling could be through alteration of biofilm EPS and alteration of the epiphytic bacterial community associated with the microalga.How to cite: Infante, C.D., Castillo, F., Pérez, V., et al. Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive compound through alteration of EPS and epiphytic bacteria. Electron J Biotechnol 2018;33 https://doi.org/10.1016/j.ejbt.2018.03.002. Keywords: Anti-fouling, Benthic microalgae, Biofilm, Biofouling, Epiphytic bacterial community, EPS, Marine ecosystems, Metagenomic, Nitzschia ovalis, Settlement inhibition

  2. Impact of organic nutrient load on biomass accumulation, feed channel pressure drop increase and permeate flux decline in membrane systems

    KAUST Repository

    Bucs, Szilard

    2014-12-01

    The influence of organic nutrient load on biomass accumulation (biofouling) and pressure drop development in membrane filtration systems was investigated. Nutrient load is the product of nutrient concentration and linear flow velocity. Biofouling - excessive growth of microbial biomass in membrane systems - hampers membrane performance. The influence of biodegradable organic nutrient load on biofouling was investigated at varying (i) crossflow velocity, (ii) nutrient concentration, (iii) shear, and (iv) feed spacer thickness. Experimental studies were performed with membrane fouling simulators (MFSs) containing a reverse osmosis (RO) membrane and a 31 mil thick feed spacer, commonly applied in practice in RO and nanofiltration (NF) spiral-wound membrane modules. Numerical modeling studies were done with identical feed spacer geometry differing in thickness (28, 31 and 34 mil). Additionally, experiments were done applying a forward osmosis (FO) membrane with varying spacer thickness (28, 31 and 34 mil), addressing the permeate flux decline and biofilm development. Assessed were the development of feed channel pressure drop (MFS studies), permeate flux (FO studies) and accumulated biomass amount measured by adenosine triphosphate (ATP) and total organic carbon (TOC).Our studies showed that the organic nutrient load determined the accumulated amount of biomass. The same amount of accumulated biomass was found at constant nutrient load irrespective of linear flow velocity, shear, and/or feed spacer thickness. The impact of the same amount of accumulated biomass on feed channel pressure drop and permeate flux was influenced by membrane process design and operational conditions. Reducing the nutrient load by pretreatment slowed-down the biofilm formation. The impact of accumulated biomass on membrane performance was reduced by applying a lower crossflow velocity and/or a thicker and/or a modified geometry feed spacer. The results indicate that cleanings can be delayed

  3. Environmental impact of condenser effluents into coastal marine environments: need for continuous monitoring

    International Nuclear Information System (INIS)

    Venugopal, V.P.

    2015-01-01

    Electric plants working on the principle of steam-water cycle require large amounts of water for condenser cooling purpose. Nuclear power plants require, on an average, about 3m 3 cooling water per minute per megawatt of electricity generated. Owning to the scarcity of large sources of freshwater for cooling, newer power plants, particularly in water-stressed parts of the world, tend to get located in coastal regions, where they can make use of the abundant seawater. However, this also poses a problem, in terms of the biofouling potential of coastal marine environments. Sessile benthic organism, which are generally present as part of the coastal marine ecosystem, extend their habitat into the cooling water system of the power plant. It is often observed that massive growth of such fouling organisms may endanger normal operation of the cooling water system, unless appropriate control measures are adopted. Presence of calcareous organisms such as mussels and barnacles in the pre-condenser sections of the power plant is a common sight; but these organisms, when lodged inside condenser tubes, can not only reduce the heat transfer efficiency but also can cause localized corrosion and tube leakage, leading of ingress of seawater into the steam-water system. It is, therefore, important that appropriate control measures are adopted to discourage the growth of the organisms. However, this needs to be done in an environmentally sustainable manner, as the cooling water is ultimately discharged back into the sea. The presentation aims to give and overview of the biofouling problems generally encountered in a typical tropical coastal power station operating in India and the chemical control measures adopted and their effectiveness. The talk also throws light on the more recent advances in biofouling control such as surface modification and use of nanotechnology which, in the foreseeable future, may provide more lasting and environmentally sustainable solutions. (author)

  4. Byssus Structure and Protein Composition in the Highly Invasive Fouling Mussel Limnoperna fortunei

    Directory of Open Access Journals (Sweden)

    Shiguo Li

    2018-04-01

    Full Text Available Biofouling mediated by byssus adhesion in invasive bivalves has become a global environmental problem in aquatic ecosystems, resulting in negative ecological and economic consequences. Previous studies suggested that mechanisms responsible for byssus adhesion largely vary among bivalves, but it is poorly understood in freshwater species. Understanding of byssus structure and protein composition is the prerequisite for revealing these mechanisms. Here, we used multiple methods, including scanning electron microscope, liquid chromatography–tandem mass spectrometry, transcriptome sequencing, real-time quantitative PCR, inductively coupled plasma mass spectrometry, to investigate structure, and protein composition of byssus in the highly invasive freshwater mussel Limnoperna fortunei. The results indicated that the structure characteristics of adhesive plaque, proximal and distal threads were conducive to byssus adhesion, contributing to the high biofouling capacity of this species. The 3,4-dihydroxyphenyl-α-alanine (Dopa is a major post-transnationally modification in L. fortunei byssus. We identified 16 representative foot proteins with typical repetitive motifs and conserved domains by integrating transcriptomic and proteomic approaches. In these proteins, Lfbp-1, Lffp-2, and Lfbp-3 were specially located in foot tissue and highly expressed in the rapid byssus formation period, suggesting the involvement of these foot proteins in byssus production and adhesion. Multiple metal irons, including Ca2+, Mg2+, Zn2+, Al3+, and Fe3+, were abundant in both foot tissue and byssal thread. The heavy metals in these irons may be directly accumulated by L. fortunei from surrounding environments. Nevertheless, some metal ions (e.g., Ca2+ corresponded well with amino acid preferences of L. fortunei foot proteins, suggesting functional roles of these metal ions by interacting with foot proteins in byssus adhesion. Overall, this study provides structural and

  5. Airfoil-shaped micro-mixers for reducing fouling on membrane surfaces

    Science.gov (United States)

    Ho, Clifford K; Altman, Susan J; Clem, Paul G; Hibbs, Michael; Cook, Adam W

    2012-10-23

    An array of airfoil-shaped micro-mixers that enhances fluid mixing within permeable membrane channels, such as used in reverse-osmosis filtration units, while minimizing additional pressure drop. The enhanced mixing reduces fouling of the membrane surfaces. The airfoil-shaped micro-mixer can also be coated with or comprised of biofouling-resistant (biocidal/germicidal) ingredients.

  6. Contribution of Charges in Polyvinyl Alcohol Networks to Marine Antifouling.

    Science.gov (United States)

    Yang, Wufang; Lin, Peng; Cheng, Daocang; Zhang, Longzhou; Wu, Yang; Liu, Yupeng; Pei, Xiaowei; Zhou, Feng

    2017-05-31

    Semi-interpenetrated polyvinyl alcohol polymer networks (SIPNs) were prepared by integrating various charged components into polyvinyl alcohol polymer. Contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and tensile tests were used to characterize the physicochemical properties of the prepared SIPNs. To investigate the contribution of charges to marine antifouling, the adhesion behaviors of green algae Dunaliella tertiolecta and diatoms Navicula sp. in the laboratory and of the actual marine animals in field test were studied for biofouling assays. The results suggest that less algae accumulation densities are observed for neutral-, anionic-, and zwitterionic-component-integrated SIPNs. However, for the cationic SIPNs, despite the hydration shell induced by the ion-dipole interaction, the resistance to biofouling largely depends on the amount of cationic component because of the possible favorable electrostatic attraction between the cationic groups in SIPNs and the negatively charged algae. Considering that the preparation of novel nontoxic antifouling coating is a long-standing and cosmopolitan industrial challenge, the SIPNs may provide a useful reference for marine antifouling and some other relevant fields.

  7. Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

    Science.gov (United States)

    Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

    2016-01-01

    A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications. PMID:27381834

  8. Antifouling aptasensor for the detection of adenosine triphosphate in biological media based on mixed self-assembled aptamer and zwitterionic peptide.

    Science.gov (United States)

    Wang, Guixiang; Su, Xiaoli; Xu, Qingjun; Xu, Guiyun; Lin, Jiehua; Luo, Xiliang

    2018-03-15

    Direct detection of targets in complex biological media with conventional biosensors is an enormous challenge due to the nonspecific adsorption and severe biofouling. In this work, a facile strategy for sensitive and low fouling detection of adenosine triphosphate (ATP) is developed through the construction of a mixed self-assembled biosensing interface, which was composed of zwitterionic peptide (antifouling material) and ATP aptamer (bio-recognition element). The peptide and aptamer (both containing thiol groups) were simultaneously self-assembled onto gold electrode surface electrodeposited with gold nanoparticles. The developed aptasensor possessed high selectivity and sensitivity for ATP, and it showed a wide linear response range towards ATP from 0.1pM to 5nM. Owing to the presence of peptide with excellent antifouling property in the biosensing interface, the aptasensor can detect ATP in complex biological media with remarkably reduced biofouling or nonspecific adsorption effect. Moreover, it can directly detect ATP in 1% human whole blood without suffering from any significant interference, indicating its great potential for practical assaying of ATP in biological samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Gold nanoparticles and polyethylene glycols functionalized conducting polyaniline nanowires for ultrasensitive and low fouling immunosensing of alpha-fetoprotein.

    Science.gov (United States)

    Hui, Ni; Sun, Xiaotian; Song, Zhiling; Niu, Shuyan; Luo, Xiliang

    2016-12-15

    An ultrasensitive biosensor for alpha-fetoprotein was developed based on electrochemically synthesized polyaniline (PANI) nanowires, which were functionalized with gold nanoparticles (AuNPs) and polyethylene glycols (PEG). The prepared PEG/AuNPs/PANI composite, combining the electrical conductivity of the AuNPs/PANI with the robust antifouling ability of PEG, offered an ideal substrate for the development of low fouling electrochemical biosensors. Alpha-fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker, was used as a model analyte, and its antibody was immobilized on the PEG/AuNPs/PANI for the construction of the AFP immunosensor. Using the redox current of PANI as the sensing signal, in addition to the good biocompatibility of PEG/AuNPs and the anti-biofouling property of PEG, the developed immunosensor showed improved biosensing performances, such as wide linear range and ultralow detection limit (0.007pgmL(-1)). More importantly, it is label-free, reagentless and low fouling, making it capable of assaying AFP in real serum samples without suffering from significant interference or biofouling. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Nano and Microscale Topographies for the Prevention of Bacterial Surface Fouling

    Directory of Open Access Journals (Sweden)

    Mary V. Graham

    2014-01-01

    Full Text Available Bacterial surface fouling is problematic for a wide range of applications and industries, including, but not limited to medical devices (implants, replacement joints, stents, pacemakers, municipal infrastructure (pipes, wastewater treatment, food production (food processing surfaces, processing equipment, and transportation (ship hulls, aircraft fuel tanks. One method to combat bacterial biofouling is to modify the topographical structure of the surface in question, thereby limiting the ability of individual cells to attach to the surface, colonize, and form biofilms. Multiple research groups have demonstrated that micro and nanoscale topographies significantly reduce bacterial biofouling, for both individual cells and bacterial biofilms. Antifouling strategies that utilize engineered topographical surface features with well-defined dimensions and shapes have demonstrated a greater degree of controllable inhibition over initial cell attachment, in comparison to undefined, texturized, or porous surfaces. This review article will explore the various approaches and techniques used by researches, including work from our own group, and the underlying physical properties of these highly structured, engineered micro/nanoscale topographies that significantly impact bacterial surface attachment.

  11. Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

    Science.gov (United States)

    Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

    2016-07-01

    A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications.

  12. Field results of antifouling techniques for optical instruments

    Science.gov (United States)

    Strahle, W.J.; Hotchkiss, F.S.; Martini, Marinna A.

    1998-01-01

    An anti-fouling technique is developed for the protection of optical instruments from biofouling which leaches a bromide compound into a sample chamber and pumps new water into the chamber prior to measurement. The primary advantage of using bromide is that it is less toxic than the metal-based antifoulants. The drawback of the bromide technique is also discussed.

  13. Microbiologically influenced corrosion in the service water system of a test reactor

    International Nuclear Information System (INIS)

    Subba Rao, T.; Venugopalan, V.P.; Nair, K.V.K.

    1995-01-01

    This paper addresses the biofouling and corrosion problems in the service water system of a test reactor. Results of microbiological, electron microscopic and chemical analyses of water and deposit samples indicate the role of bacteria in the corrosion process. The primary role played by iron oxidising bacteria is emphasised. (author). 7 refs., 2 figs., 1 tab

  14. The Antifouling of ACLW-CAR Based on Ultrasonic Cleaner

    Science.gov (United States)

    Zhang, Guohua; Liu, Shixuan; Qin, Qingliang

    2017-10-01

    Equipped with ACLW-CAR, the buoy provided effective technical platform for on-site rapid monitoring of the chlorophyll and turbidity. Performance index and usage in the ocean buoy of ACLW-CAR was introduced. Ultrasonic cleaning method in seawater was developed for preventing ACLW-CAR from biofouling. Marine chlorophyll and turbidity data can serve for oceanographic research and marine resource exploitation.

  15. Zebra Mussel Chemical Control Guide, Version 2.0

    Science.gov (United States)

    2015-07-01

    are biodegradable , some detoxification or deactivation may be required to meet state and Federal discharge requirements. See the topic “Adjuvant...information. Adjuvant/Detoxicant/Deactivant Use Although most molluscicides are biodegradable , some detoxification or deactivation may be required to... microorganisms in commercial and industrial water systems. It also is an effective molluscicide and can prevent biofouling by mollusks (Martin et al. 1993a

  16. Controlling Biofouling in Seawater Reverse Osmosis Membrane Systems

    NARCIS (Netherlands)

    Dhakal, N.

    2017-01-01

    Seawater desalination is a rapidly growing coastal industry that is increasingly threatened by algal blooms. Depending on the severity of algal blooms, desalination systems may be forced to shut down because of clogging and/or poor feed water quality. To maintain stable operation and provide good

  17. Monitorizing nitinol alloy surface reactions for biofouling studies

    International Nuclear Information System (INIS)

    Dinu, C.Z.; Dinca, V.C.; Soare, S.; Moldovan, A.; Smarandache, D.; Scarisoareanu, N.; Barbalat, A.; Birjega, R.; Dinescu, M.; DiStefano, V. Ferrari

    2007-01-01

    Growth and deposition of unwanted bacteria on implant metal alloys affect their use as biomedical samples. Monitoring any bacterial biofilm accumulation will provide early countermeasures. For a reliable antifouling strategy we prepared nitinol (NiTi) thin films on Ti-derived substrates by using a pulsed laser deposition (PLD) method. As the microstructure of Ti-alloy is dictated by the tensile strength, fatigue and the fracture toughness we tested the use of hydrogen as an alloying element. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) investigated the crystalline structure, chemical composition and respectively the surface morphology of the nitinol hydrogen and hydrogen-free samples. Moreover, the alloys were integrated and tested using a cellular metric and their responses were systematic evaluated and quantified. Our attractive approach is meant to select the suitable components for an effective and trustworthy anti-fouling strategy. A greater understanding of such processes should lead to novel and effective control methods that would improve in the future implant stability and capabilities

  18. Biofouling in reverse and forward osmosis membrane systems

    NARCIS (Netherlands)

    Bucs, S.S.

    2017-01-01

    Global freshwater demand has significantly increased over the past century and continued growth is expected in the coming century. Since more than 97 percent of the water in the world is seawater, desalination technologies have the potential to solve the fresh water crisis. Currently, the most used

  19. Processes And Apparatus For Inhibiting Membrane Bio-fouling

    KAUST Repository

    Missimer, Thomas M.

    2012-12-20

    Certain embodiments are directed to a process and apparatus for cleaning and/or regeneration of permeable or semipermeable membranes comprising modulating pressure of a feed stream feeding the permeable or semipermeable membrane and providing intermittent pressure pulses for cleaning and/or regeneration of the permeable or semipermeable membrane.

  20. Prevention of biofouling and biocorrosion in reactor systems

    International Nuclear Information System (INIS)

    Mathur, A.K.; Shivananda, S.R.

    1995-01-01

    Formaldehyde even at 500 μl/l concentration can prevent the growth of bacteria, algae and fungi in thermal reactors there by stopping the chances of biocorrosion and plugging of the pipe lines. (author). 5 refs., 1 fig

  1. Processes And Apparatus For Inhibiting Membrane Bio-fouling

    KAUST Repository

    Missimer, Thomas M.; Ng, Kim Choon; Amy, Gary

    2012-01-01

    Certain embodiments are directed to a process and apparatus for cleaning and/or regeneration of permeable or semipermeable membranes comprising modulating pressure of a feed stream feeding the permeable or semipermeable membrane and providing intermittent pressure pulses for cleaning and/or regeneration of the permeable or semipermeable membrane.

  2. Fluorogel Elastomers with Tunable Transparency, Elasticity, Shape-Memory, and Antifouling Properties**

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Xi; Dunn, Stuart; Kim, Philseok; Duffy, Meredith; Alvarenga, Jack; Aizenberg, Joanna

    2014-04-22

    Omniphobic fluorogel elastomers were prepared by photocuring perfluorinated acrylates and a perfluoropolyether crosslinker. By tuning either the chemical composition or the temperature that control the crystallinity of the resulting polymer chains, a broad range of optical and mechanical properties of the fluorogel can be achieved. After infusing with fluorinated lubricants, the fluorogels showed excellent resistance to wetting by various liquids and anti-biofouling behavior, while maintaining cytocompatiblity.

  3. Fluorogel Elastomers with Tunable Transparency, Elasticity, ShapeMemory, and Antifouling Properties**

    Energy Technology Data Exchange (ETDEWEB)

    Yao, X; Dunn, SS; Kim, P; Duffy, M; Alvarenga, J; Aizenberg, J

    2014-03-18

    Omniphobic fluorogel elastomers were prepared by photocuring perfluorinated acrylates and a perfluoropolyether crosslinker. By tuning either the chemical composition or the temperature that control the crystallinity of the resulting polymer chains, a broad range of optical and mechanical properties of the fluorogel can be achieved. After infusing with fluorinated lubricants, the fluorogels showed excellent resistance to wetting by various liquids and anti-biofouling behavior, while maintaining cytocompatiblity.

  4. The Institute of Biological Engineering 2013 Annual Conference

    Science.gov (United States)

    2014-10-30

    Spores Liju Yang, North Carolina Central University 5:30 pm The Effects of the Electrical Double Layer on Giant Ionic Currents through Single Walled...unexpectedly, urease activity (Maeda et al., 2008) (Sakamoto, 1998). Thus, the trends in FFA production may be related to the effects of lipid...surfaces and coatings that proved to show efficient release (> 90 %) of tenaciously adhered biofouling layers and organisms. The results successfully

  5. Cooling water treatment for heavy water project (Paper No. 6.9)

    International Nuclear Information System (INIS)

    Valsangkar, H.N.

    1992-01-01

    With minor exceptions, water is the preferred industrial medium for the removal of unwanted heat from process systems. The application of various chemical treatments is required to protect the system from water related and process related problems of corrosion, scale and deposition and biofouling. The paper discusses the cooling water problems for heavy water industries along with the impact caused by associated fertilizer units. (author). 6 figs

  6. Fungi and their role in corals and coral reef ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Ravindran, J.

    fungal hyphae have on corals, their mechanism of penetration and the role their enzymes play in this process. 3.2. Fungi as pathogens in reef ecosystems Besides natural disasters and climate warming, diseases have contributed to coral decline... defence mechanisms against predation, biofouling, diseases, environmental perturbations and other stressors. These chemicals are either synthesized by the organisms themselves or their endobiontic microorganisms. If these valuable compounds...

  7. Antifouling processes and toxicity effects of antifouling paints on marine environment. A review.

    Science.gov (United States)

    Amara, Intissar; Miled, Wafa; Slama, Rihab Ben; Ladhari, Neji

    2018-01-01

    The production infrastructure in aquaculture invariably is a complex assortment of submerged components with cages, nets, floats and ropes. Cages are generally made from polyamide or high density polyethylene (PEHD). All of these structures serve as surfaces for biofouling. However, cage nets and supporting infrastructure offer fouling organisms thousands of square meters of multifilament netting. That's why, before immersing them in seawater, they should be coated with an antifouling agent. It helps to prevent net occlusion and to increase its lifespan. Biofouling in marine aquaculture is a specific problem and has three main negative effects. It causes net occlusion and so restricts water and oxygen exchange. Besides, the low dissolved oxygen levels from poor water exchange increases the stress levels of fish, lowers immunity and increases vulnerability to disease. Also, the extra weight imposed by fouling causes cage deformation and structural fatigue. The maintenance and loss of equipment cause the increase of production costs for the industry. Biocides are chemical substances that can prohibit or kill microorganisms responsible for biofouling. The expansion of the aquaculture industry requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. Unfortunately, the use of biocides in the aquatic environment has proved to be harmful as it has toxic effects on the marine environment. The most commonly used biocides in antifouling paints are Tributyltin (TBT), Chlorothalonil, Dichlofluanid, Sea-Nine 211, Diuron, Irgarol 1051 and Zinc Pyrithione. Restrictions were imposed on the use of TBT, that's why organic booster biocides were recently introduced. The replacement products are generally based on copper metal oxides and organic biocides. This paper provides an overview of the effects of antifouling biocides on aquatic organisms. It will focus on the eight booster biocides in

  8. Improving the antimicrobial properties of titanium condenser material by surface modification using nanotechnology

    International Nuclear Information System (INIS)

    George, Rani P.; Dash, S.; Krishnan, R.; Kamruddin, M.; Kalavathi, S.; Tyagi, A.K.; Manoharan, N.; Dayal, R.K.; Vishwakarma, Vinita; Theresa, Josephine

    2008-01-01

    Biofouling is one of the major problems faced by condenser materials of power plants using seawater for cooling. Fouling control strategies in condensers include a combination of mechanical and chemical treatments like sponge ball cleaning, back washing and chlorination. In general, numerous studies have shown that no routine treatment regime can successfully keep the condenser tube clean over a period extending to years. Surface properties of the substratum influence initial adhesion and growth of bacterial cells on materials, modification of the surface for mitigating microbial attachment is the need of the hour. Metal nanoparticles are known to exhibit enhanced physical and chemical properties when compared to their bulk counter parts because of their high surface to volume ratios. Metals like copper are very toxic to microorganisms and effectively kill most of the microbes by blocking the respiratory enzyme. Copper alloys with their excellent resistance to biofouling are used extensively for marine applications. However, they are prone to localized corrosion initiation and consequently are getting replaced by extremely corrosion resistant titanium. Still, the inertness and biocompatibility of titanium makes it very susceptible to biofouling. Hence, this study attempts to use nano technology methods of surface modification of titanium using thin film of copper and also multilayers and bilayers of copper and nickel. This is aimed at improving the antimicrobial properties of this condenser pipe material. These nano structured thin films have been grown on titanium substrate using pulsed DC magnetron-sputtering and pulsed laser deposition. The thin films were characterized using Atomic Force Microscopy (AFM), Glancing Incidence X-ray Diffraction (GIXRD) and scanning electron microscopy (SEM with EDAX analysis). Antimicrobial properties were evaluated by exposure studies in seawater and bacterial cultures and by post exposure analysis using culture and

  9. Transport of microplastics in coastal seas

    Science.gov (United States)

    Zhang, Hua

    2017-12-01

    Microplastic pollution of the marine environment has received increasing attention from scientists, the public, and policy makers over the last few years. Marine microplastics predominantly originate near the coast and can remain in the nearshore zone for some time. However, at present, there is little understanding of the fate and transport of microplastics in coastal regions. This paper provides a comprehensive overview of the physical processes involved in the movement of microplastics from estuaries to the continental shelf. The trajectory and speed of microplastics are controlled by their physical characteristics (density, size, and shape) and ocean dynamic conditions (wind, waves, tides, thermohaline gradients, and the influence of benthic sediments). Microplastic particles can be subjected to beaching, surface drifting, vertical mixing, and biofouling, as well as bed-load and suspended load transport processes, until reaching terminal deposition on beaches, in coastal marshes, in benthic sediments or until they are carried by ocean currents to subtropical convergence zones. The dynamic interaction of released microplastics with the shoreline is regulated by onshore/offshore transport, which is impacted by the source location as well as the geometry, vegetation, tidal regime, and wave direction. Wind and wave conditions dominate surface drifting of buoyant particles through Ekman drift, windage, and Stokes drift mechanisms. Neustic microplastic particles travel in the subsurface because of vertical mixing through wind-driven Langmuir circulation and heat cycling. Increasing accumulation of microplastics in benthic sediments needs to be quantitatively explored in terms of biofouling, deposition, entrainment, and transport dynamics. Further studies are required to understand the following: 1) the primary parameters (e.g., windage, terminal velocity, diffusivity, critical shear stress) that determine microplastic transport in different pathways; 2) dynamic

  10. Self-Cleaning Coatings and Materials for Decontaminating Field-Deployable Land and Water-Based Optical Systems

    Science.gov (United States)

    Ryan, Robert; Underwood, Lauren; Holekamp, Kara; May, George; Spiering, Bruce; Davis, Bruce

    2011-01-01

    This technology exploits the organic decomposition capability and hydrophilic properties of the photocatalytic material titanium dioxide (TiO2), a nontoxic and non-hazardous substance, to address contamination and biofouling issues in field-deployed optical sensor systems. Specifically, this technology incorporates TiO2 coatings and materials applied to, or integrated as a part of, the optical surfaces of sensors and calibration sources, including lenses, windows, and mirrors that are used in remote, unattended, ground-based (land or maritime) optical sensor systems. Current methods used to address contamination or biofouling of these optical surfaces in deployed systems are costly, toxic, labor intensive, and non-preventative. By implementing this novel technology, many of these negative aspects can be reduced. The functionality of this innovative self-cleaning solution to address the problem of contamination or biofouling depends on the availability of a sufficient light source with the appropriate spectral properties, which can be attained naturally via sunlight or supplemented using artificial illumination such as UV LEDs (light emitting diodes). In land-based or above-water systems, the TiO2 optical surface is exposed to sunlight, which catalyzes the photocatalytic reaction, facilitating both the decomposition of inorganic and organic compounds, and the activation of superhydrophilic properties. Since underwater optical surfaces are submerged and have limited sunlight exposure, supplementary UV light sources would be required to activate the TiO2 on these optical surfaces. Nighttime operation of land-based or above-water systems would require this addition as well. For most superhydrophilic self-cleaning purposes, a rainwater wash will suffice; however, for some applications an attached rainwater collector/ dispenser or other fresh water dispensing system may be required to wash the optical surface and initiate the removal of contaminates. Deployment of this

  11. Distribution of butyltins in waters and sediments of the Mandovi and Zuari estuaries, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Garg, A.; Meena, R; Bhosle, N.B.

    ., Philips, I. R., & Hawker, D. W. (2004). Sorption and desorption behaviour of tributyltin with natural sediments. Environmental Science Technology, 38, 6694-6700. CCME (1992). Canadian water quality guidelines: Canadian Council of Ministers..., agrichemicals and in glass coatings (Bhosle 2006). The predominant source of organotins in the marine waters is related to their use as biocides in antifouling paints, especially tributyltin (TBT). In order to control biofouling about 70% of the worlds...

  12. An Assessment of Alternative Diesel Fuels: Microbiological Contamination and Corrosion Under Storage Conditions

    Science.gov (United States)

    2010-08-01

    and B20) In experiments with additions of distilled water, all fuels supported biofilm formation Changes in the water pH did not correlate with...ULSD) and blends of ULSD and B100 (B5 and B20). In experiments with additions of distilled water, all fuels supported biofilm formation . Changes in...corrosion; diesel; biodiesel; biofouling; MIC; carbon steel ; aluminum; stainless steel Introduction Microbial contamination of hydrocarbon fuels

  13. Adsorption of alginate and albumin on aluminum coatings inhibits adhesion of Escherichia coli and enhances the anti-corrosion performances of the coatings

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaoyan; Liu, Yi; Huang, Jing; Chen, Xiuyong; Ren, Kun; Li, Hua, E-mail: lihua@nimte.ac.cn

    2015-03-30

    Graphical abstract: - Highlights: • Adsorption behaviors of alginate and albumin on Al coatings were investigated at molecular level. • The adsorption inhibits effectively the colonization of Escherichia coli bacteria. • The adsorption alters the wettability of the Al coatings. • The conditioning layer enhances anti-corrosion performances of the Al coatings. - Abstract: Thermal-sprayed aluminum coatings have been extensively used as protective layers against corrosion for steel structures in the marine environment. The corrosion usually deteriorates from marine biofouling, yet the mechanism of accelerated corrosion of the coatings remains elusive. As the first stage participating in biofouling process, adsorption of molecules plays critical roles in mediating formation of biofilm. Here, we report at molecular level the adsorption behaviors of albumin and marine polysaccharide on arc-sprayed aluminum coatings and their influence on adhesion of Escherichia coli. The adsorption of alginate and albumin was characterized by infrared spectra analyses and atomic force microscopic observation. The adsorption inhibits effectively adhesion of the bacteria. Further investigation indicates that alginate/albumin altered the hydrophilicity/hydrophobicity of the coatings instead of impacting the survival of the bacteria to decline their adhesion. The conditioning layer composed of the molecules enhances anti-corrosion performances of the coatings.

  14. Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions

    Directory of Open Access Journals (Sweden)

    Pauliina Rajala

    2016-06-01

    Full Text Available Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials’ degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V, super austenitic stainless steel (254SMO and epoxy-coated carbon steel (Intershield Inerta160 were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10–1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating.

  15. Assessing the Antimicrobial Activity of Polyisoprene Based Surfaces

    Directory of Open Access Journals (Sweden)

    Hope Badawy

    2015-02-01

    Full Text Available There has been an intense research effort in the last decades in the field of biofouling prevention as it concerns many aspects of everyday life and causes problems to devices, the environment, and human health. Many different antifouling and antimicrobial materials have been developed to struggle against bacteria and other micro- and macro-organism attachment to different surfaces. However the “miracle solution” has still to be found. The research presented here concerns the synthesis of bio-based polymeric materials and the biological tests that showed their antifouling and, at the same time, antibacterial activity. The raw material used for the coating synthesis was natural rubber. The polyisoprene chains were fragmented to obtain oligomers, which had reactive chemical groups at their chain ends, therefore they could be modified to insert polymerizable and biocidal groups. Films were obtained by radical photopolymerization of the natural rubber derived oligomers and their structure was altered, in order to understand the mechanism of attachment inhibition and to increase the efficiency of the anti-biofouling action. The adhesion of three species of pathogenic bacteria and six strains of marine bacteria was studied. The coatings were able to inhibit bacterial attachment by contact, as it was verified that no detectable leaching of toxic molecules occurred.

  16. Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions.

    Science.gov (United States)

    Rajala, Pauliina; Bomberg, Malin; Huttunen-Saarivirta, Elina; Priha, Outi; Tausa, Mikko; Carpén, Leena

    2016-06-15

    Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials' degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V), super austenitic stainless steel (254SMO) and epoxy-coated carbon steel (Intershield Inerta160) were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10-1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating.

  17. Monitoring and toxicity evaluation of phytoplankton on lithium manganese oxide adsorbents at lithium recovery pilot plant field.

    Science.gov (United States)

    Yoon, H. O.; Kim, J. A.; Kim, J. C.; Chung, K. S.; Ryu, J. H.

    2015-12-01

    For recovery of rare mineral resources such as lithium or boron from seawater, the lithium adsorbent material have been made by Korea Institute of Geoscience and Mineral Resources (KIGAM) and pilot plant was conducted in Okgye Harbor, Gangneung, Korea. The application of lithium adsorbent in pilot plant, it is important to consider the impact on the marine environment. Especially phytoplankton communities are important marine microorganism to represent marine primary product. At the same time, phytoplankton is possible to induce the decrease of lithium recovery rate due to cause of biofouling to surfaces of lithium adsorbents. Therefore long-term and periodic monitoring of phytoplankton is necessary to understand the environmental impact and biofouling problems near the lithium pilot plant. The abundance and biomass of phytoplankton have been evaluated through monthly interval sampling from February 2013 to May 2015. Abundance and species diversity of phytoplankton went up to summer from winter. When lithium adsorbents were immersing to seawater, eco-toxicities of released substances were determined using Microtox with bioluminescence bacteria Vibrio fischeri. The adsorbents were soaked in sterilized seawater and aeration for 1, 3, 5, 7, 10 and 14 days intervals under controlled temperature. Maximum EC50 concentration was 61.4% and this toxicity was showed in more than 10 days exposure.

  18. OCEAN THERMAL ENERGY CONVERSION (OTEC) PROGRAMMATIC ENVIRONMENTAL ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Sands, M. D.

    1980-01-01

    This programmatic environmental analysis is an initial assessment of OTEC technology considering development, demonstration and commercialization; it is concluded that the OTEC development program should continue because the development, demonstration, and commercialization on a single-plant deployment basis should not present significant environmental impacts. However, several areas within the OTEC program require further investigation in order to assess the potential for environmental impacts from OTEC operation, particularly in large-scale deployments and in defining alternatives to closed-cycle biofouling control: (1) Larger-scale deployments of OTEC clusters or parks require further investigations in order to assess optimal platform siting distances necessary to minimize adverse environmental impacts. (2) The deployment and operation of the preoperational platform (OTEC-1) and future demonstration platforms must be carefully monitored to refine environmental assessment predictions, and to provide design modifications which may mitigate or reduce environmental impacts for larger-scale operations. These platforms will provide a valuable opportunity to fully evaluate the intake and discharge configurations, biofouling control methods, and both short-term and long-term environmental effects associated with platform operations. (3) Successful development of OTEC technology to use the maximal resource capabilities and to minimize environmental effects will require a concerted environmental management program, encompassing many different disciplines and environmental specialties.

  19. Microfouling development on artificial substrates deployed in the central Red Sea

    Directory of Open Access Journals (Sweden)

    Ahmed A. Balqadi

    2018-04-01

    Full Text Available Summary: Microfouling is the initial step in the growth of biofouling on hard substrata submerged in marine waters. In this study, microfouling development on nylon nets submerged in the central Red Sea coast of Saudi Arabia was analyzed during the winter and summer seasons for a period of 5 days each. The results showed a well-established biofilm community on nylon nets submerged for 24 h, with bacteria and diatoms being the primary colonizers. Protein was the major organic component of the biofilm that developed on the nylon nets during the winter and summer seasons. Navicula spp., Nitzschia spp., Cylindrotheca spp., and Pluerosigma spp. were the dominant diatom species settled on the nylon nets. Pseudoalteromonas shioyasakiensis, Planomicrobium sp., Vibrio harveyi and Pseudoalteromonas rubra were the dominant bacteria isolated from the nylon nets. While the abundance of bacteria showed a positive correlation with the nutrient concentration of the biofilm during both winter and summer seasons, diatom density exhibited a significant positive relationship with the biofilm nutrients during the winter season only. The results also revealed significant seasonal variations in the abundance of microfouling organisms and accumulation of nutrients on nylon nets. Keywords: Biofilm, Biofouling, Nutrient cycling, Diatom, Larval settlement, Red Sea

  20. Marketing netcoatings for aquaculture.

    Science.gov (United States)

    Martin, Robert J

    2014-10-17

    Unsustainable harvesting of natural fish stocks is driving an ever growing marine aquaculture industry. Part of the aquaculture support industry is net suppliers who provide producers with nets used in confining fish while they are grown to market size. Biofouling must be addressed in marine environments to ensure maximum product growth by maintaining water flow and waste removal through the nets. Biofouling is managed with copper and organic biocide based net coatings. The aquaculture industry provides a case study for business issues related to entry of improved fouling management technology into the marketplace. Several major hurdles hinder entry of improved novel technologies into the market. The first hurdle is due to the structure of business relationships. Net suppliers can actually cut their business profits dramatically by introducing improved technologies. A second major hurdle is financial costs of registration and demonstration of efficacy and quality product with a new technology. Costs of registration are prohibitive if only the net coatings market is involved. Demonstration of quality product requires collaboration and a team approach between formulators, net suppliers and farmers. An alternative solution is a vertically integrated business model in which the support business and product production business are part of the same company.

  1. Introduction to the symposium--barnacle biology: essential aspects and contemporary approaches.

    Science.gov (United States)

    Zardus, John D

    2012-09-01

    Barnacles have evolved a number of specialized features peculiar for crustaceans: they produce a calcified, external shell; they exhibit sexual strategies involving dioecy and androdioecy; and some have become internal parasites of other Crustacea. The thoroughly sessile habit of adults also belies the highly mobile and complex nature of their larval stages. Given these and other remarkable innovations in their natural history, it is perhaps not surprising that barnacles present a spectrum of opportunities for study. This symposium integrates research on barnacles in the areas of larval biology, biofouling, reproduction, biogeography, speciation, population genetics, ecological genomics, and phylogenetics. Pioneering comparisons are presented of metamorphosis among barnacles from three major lineages. Biofouling is investigated from the perspectives of biochemical and biomechanical mechanisms. Tradeoffs in reproductive specializations are scrutinized through theoretical modeling and empirical validation. Patterns of endemism and diversity are delineated in Australia and intricate species boundaries in the genus Chthamalus are elucidated for the Indo-Pacific. General methodological concerns with population expansion studies in crustaceans are highlighted using barnacle models. Data from the first, draft barnacle genome are employed to examine location-specific selection. Lastly, barnacle evolution is framed in a deep phylogenetic context and hypothetical origins of defined characters are outlined and tested.

  2. Adsorption of alginate and albumin on aluminum coatings inhibits adhesion of Escherichia coli and enhances the anti-corrosion performances of the coatings

    International Nuclear Information System (INIS)

    He, Xiaoyan; Liu, Yi; Huang, Jing; Chen, Xiuyong; Ren, Kun; Li, Hua

    2015-01-01

    Graphical abstract: - Highlights: • Adsorption behaviors of alginate and albumin on Al coatings were investigated at molecular level. • The adsorption inhibits effectively the colonization of Escherichia coli bacteria. • The adsorption alters the wettability of the Al coatings. • The conditioning layer enhances anti-corrosion performances of the Al coatings. - Abstract: Thermal-sprayed aluminum coatings have been extensively used as protective layers against corrosion for steel structures in the marine environment. The corrosion usually deteriorates from marine biofouling, yet the mechanism of accelerated corrosion of the coatings remains elusive. As the first stage participating in biofouling process, adsorption of molecules plays critical roles in mediating formation of biofilm. Here, we report at molecular level the adsorption behaviors of albumin and marine polysaccharide on arc-sprayed aluminum coatings and their influence on adhesion of Escherichia coli. The adsorption of alginate and albumin was characterized by infrared spectra analyses and atomic force microscopic observation. The adsorption inhibits effectively adhesion of the bacteria. Further investigation indicates that alginate/albumin altered the hydrophilicity/hydrophobicity of the coatings instead of impacting the survival of the bacteria to decline their adhesion. The conditioning layer composed of the molecules enhances anti-corrosion performances of the coatings

  3. In-situ assessment of biofilm formation in submerged membrane system using optical coherence tomography and computational fluid dynamics

    KAUST Repository

    Fortunato, Luca

    2016-09-09

    This paper introduces a novel approach to study the biofouling development on gravity driven submerged membrane bioreactor (SMBR). The on-line monitoring of biofilm formation on a flat sheet membrane was conducted non-destructively using optical coherence tomography (OCT), allowing the in-situ investigation of the biofilm structure for 43 d. The OCT enabled to obtain a time-lapse of biofilm development on the membrane under the continuous operation. Acquired real-time information on the biofilm structure related to the change in the flux profile confirming the successful monitoring of the dynamic evolution of the biofouling layer. Four different phases were observed linking the permeate flux with the change of biofilm morphology. In particular, a stable flux of 2.1±0.1 L/m2 h was achieved with the achievement of steady biofilm morphology after 30 d of operation. Biofilm descriptors, such as thickness, biofilm area, macro-porosity and roughness (absolute and relative), were calculated for each OCT acquired scans. Interestingly, relative roughness was correlated with the flux decrease. Furthermore, the precise biofilm morphology obtained from the OCT scans was used in computational fluid dynamics (CFD) simulation to better understand the role of biofilm structure on the filtration mechanism. © 2016 Elsevier B.V.

  4. Calibration procedure for Slocum glider deployed optical instruments.

    Science.gov (United States)

    Cetinić, Ivona; Toro-Farmer, Gerardo; Ragan, Matthew; Oberg, Carl; Jones, Burton H

    2009-08-31

    Recent developments in the field of the autonomous underwater vehicles allow the wide usage of these platforms as part of scientific experiments, monitoring campaigns and more. The vehicles are often equipped with sensors measuring temperature, conductivity, chlorophyll a fluorescence (Chl a), colored dissolved organic matter (CDOM) fluorescence, phycoerithrin (PE) fluorescence and spectral volume scattering function at 117 degrees, providing users with high resolution, real time data. However, calibration of these instruments can be problematic. Most in situ calibrations are performed by deploying complementary instrument packages or water samplers in the proximity of the glider. Laboratory calibrations of the mounted sensors are difficult due to the placement of the instruments within the body of the vehicle. For the laboratory calibrations of the Slocum glider instruments we developed a small calibration chamber where we can perform precise calibrations of the optical instruments aboard our glider, as well as sensors from other deployment platforms. These procedures enable us to obtain pre- and post-deployment calibrations for optical fluorescence instruments, which may differ due to the biofouling and other physical damage that can occur during long-term glider deployments. We found that biofouling caused significant changes in the calibration scaling factors of fluorescent sensors, suggesting the need for consistent and repetitive calibrations for gliders as proposed in this paper.

  5. The Department of Defense Statement on the Defense Energy Technology Program by Ruth M. Davis Deputy Under Secretary of Defense for Research and Advanced Technology before the Research and Development subcommittee of the Committee on Armed Services of the United States House of Representatives 96th Congress, First Session,

    Science.gov (United States)

    1979-04-05

    aircraft through engine efficiency improvements. o In other Air Force sponsored research, the KC-135 winglet program is anticipated to result in a 15...percent reduction in drag and a 5 percent improvement in overall aerodynamic efficiency, which will result in a 37.6 million-gallon annual fuel...removal of biofouling from underwater hull surfaces, and the Air Force program to reduce aircraft drag through the use of winglets and by modifying the win

  6. Underwater Ship Husbandry Discharges

    Science.gov (United States)

    2011-11-01

    which entered into force in September of 2008, prohibits the use of harmful organotins such as tributyltin ( TBT ) in AFCs used on international...States. The use of TBT AFCs is explicitly prohibited under the VGP, and vessels must remove such coatings or paint over them to prevent toxic ...to hull husbandry include (1) the discharge of toxic chemicals used as biocides in AFCs and (2) biofouling as a vector for aquatic nuisance species

  7. Field study of the long-term release of block copolymers from fouling-release coatings

    DEFF Research Database (Denmark)

    Noguer, Albert Camós; Olsen, A.; Hvilsted, Søren

    2017-01-01

    The addition of block copolymers (i.e. oils) is a common technique to enhance the biofouling-resistance properties of poly(dimethylsiloxane) (PDMS)-based fouling-release coatings. These copolymers diffuse from the bulk to the surface of the coating, thus modifying the properties of the surface an...... fouling-release coatings. Finally, the potential of long-term field-studies is discussed, as compared to short-term laboratory experiments usually performed within fouling-release coatings studies....

  8. Making the Best of a Pest: The Potential for Using Invasive Zebra Mussel (Dreissena Polymorpha) Biomass as a Supplement to Commercial Chicken Feed

    OpenAIRE

    McLaughlan, Claire; Rose, Paul; Aldridge, David C.

    2014-01-01

    Invasive non-native species frequently occur in very high densities. Where such invaders present an economic or ecological nuisance this biomass is typically removed and landfill is the most common destination, which is undesirable from both an economic and ecological perspective. The zebra mussel, Dreissena polymorpha, has invaded large parts of Europe and North America, and is routinely removed from raw water systems where it creates a biofouling nuisance. We investigated the suitability...

  9. Instrument packages to study long-term sediment transport processes in a shallow bay

    Science.gov (United States)

    Strahle, William J.; Martini, Marinna A.; Davis, Ray E.

    1994-01-01

    Pressure and near-surface and near-bottom measurements of current, temperature, salinity and light transmission were required in Mobile Bay, a 3 m deep estuary on the Gulf of Mexico. This environment presented several obstacles to obtaining long term observations. Boat traffic, soft estuary bottom, heavy biofouling, rapid sample rates and large data storage were overcome by using instrumentation techniques that are applicable to other estuary systems. Nearly two years of continuous data was collected.

  10. Use of Treated Municipal Wastewater as Power Plant Cooling System Makeup Water: Tertiary Treatment versus Expanded Chemical Regimen for Recirculating Water Quality Management

    Energy Technology Data Exchange (ETDEWEB)

    David Dzombak; Radisav Vidic; Amy Landis

    2012-06-30

    Treated municipal wastewater is a common, widely available alternative source of cooling water for thermoelectric power plants across the U.S. However, the biodegradable organic matter, ammonia-nitrogen, carbonate and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and life cycle costs of implementing tertiary treatment of secondary treated municipal wastewater prior to use in recirculating cooling systems. The study comprised bench- and pilot-scale experimental studies with three different tertiary treated municipal wastewaters, and life cycle costing and environmental analyses of various tertiary treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three tertiary treated wastewaters studied were: secondary treated municipal wastewater subjected to acid addition for pH control (MWW_pH); secondary treated municipal wastewater subjected to nitrification and sand filtration (MWW_NF); and secondary treated municipal wastewater subjected nitrification, sand filtration, and GAC adsorption (MWW_NFG). Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated municipal wastewater in power plant cooling systems. The ability to control scaling, in particular, was found to be significantly enhanced with tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4-5 ppm TTA), however, which was the case for all of the tertiary treated waters. For MWW_NF treated water, the removal of ammonia by

  11. Biofouling and Design of a Biomimetic Hull-Grooming Tool

    Science.gov (United States)

    2007-09-14

    have barred the use of organotin compounds such as tributyltin ( TBT ) and copper-based paints, which are currently used by the Navy and have become...copper into the water, killing the fouling organisms. There is new research in biomimetic polymers that deter fouling, but are non- toxic . These polymers...is new research in biomimetic polymers that deter fouling, but are non- toxic . These polymers are rigidly attached to the hull surface extending

  12. Marine biofouling resistance of polyurethane with biodegradation and hydrolyzation.

    Science.gov (United States)

    Xu, Wentao; Ma, Chunfeng; Ma, Jielin; Gan, Tiansheng; Zhang, Guangzhao

    2014-03-26

    We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.

  13. Online monitoring of biofouling using coaxial stub resonator technique

    NARCIS (Netherlands)

    Hoog-Antonyuk, N.A.; Mayer, M.J.J.; Miedema, H.; Olthuis, Wouter; Tomaszweska, A.A.; Paulitsch-Fuchs, A.H.; van den Berg, Albert

    Here we demonstrate the proof-of-principle that a coaxial stub resonator can be used to detect early stages of biofilm formation. After promising field tests using a stub resonator with a stainless steel inner conductor as sensitive element, the sensitivity of the system was improved by using a

  14. Biomimicking micropatterned surfaces and their effect on marine biofouling

    NARCIS (Netherlands)

    Brzozowska, Agata M.; Parra-Velandia, Fernando J.; Quintana, Robert; Xiaoying, Zhu; Lee, Serina Siew Chen; Chin-Sing, Lim; Jańczewski, Dominik; Teo, Serena Lay Ming; Vancso, Julius G.

    2014-01-01

    When synthetic materials are submerged in marine environments, dissolved matter and marine organisms attach to their surfaces by a process known as marine fouling. This phenomenon may lead to diminished material performance with detrimental consequences. Bioinspired surface patterning and chemical

  15. Impact of biofouling on corrosion resistance of reinforced concrete

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, B.T.; Gajendragad, M.R.; Ranganna, G.; Wagh, A.B.; Sudhakaran, T.

    the structure from deterioration; a nonuniform deposit can lead to severe localized pitting corrosion. To study this cylindrical reinforced concrete electrodes were exposed to seawater. They were periodically removed and examined for the presence of fouling...

  16. Biofouling Removal and Protein Detection Using a Hypersonic Resonator.

    Science.gov (United States)

    Pan, Shuting; Zhang, Hongxiang; Liu, Wenpeng; Wang, Yanyan; Pang, Wei; Duan, Xuexin

    2017-08-25

    Nonspecific binding (NSB) is a general issue for surface based biosensors. Various approaches have been developed to prevent or remove the NSBs. However, these approaches either increased the background signals of the sensors or limited to specific transducers interface. In this work, we developed a hydrodynamic approach to selectively remove the NSBs using a microfabricated hypersonic resonator with 2.5 gigahertz (GHz) resonant frequency. The high frequency device facilitates generation of multiple controlled microvortexes which then create cleaning forces at the solid-liquid interfaces. The competitive adhesive and cleaning forces have been investigated using the finite element method (FEM) simulation, identifying the feasibility of the vortex-induced NSB removal. NSB proteins have been selectively removed experimentally both on the surface of the resonator and on other substrates which contact the vortexes. Thus, the developed hydrodynamic approach is believed to be a simple and versatile tool for NSB removal and compatible to many sensor systems. The unique feature of the hypersonic resonator is that it can be used as a gravimetric sensor as well; thus a combined NSB removal and protein detection dual functional biosensor system is developed.

  17. Treatment of Biofouling in Internal Seawater Systems - Phase 2

    National Research Council Canada - National Science Library

    Lewis, John A; Dimas, Jim

    2007-01-01

    .... Mussels are of particular concern. In this study, a range of chemicals, including vinegar, detergents, disinfectants, bleach, descalers, pipework treatments and freshwater, were tested on the southern Australian blue mussel, Mytilus...

  18. Corrosion and Biofouling of OTEC System Surfaces - Design Factors

    Science.gov (United States)

    1978-11-01

    condition between different areas on a given member can lead to accelerated attack by a differential envirornment cell . These differences can be...resistance. As shown in Figure 1, -. gal- vanic cell is essentially a battery/load system. When the intermetallic resistance, R1 , or the environmental...members of a couple should be maximized when possible. Also, insulating or high resistance F bushings, etc., can reduce or el4 !.minate galvanic corrosion

  19. Innovative coatings and surface modification of titanium for sea water condenser applications

    International Nuclear Information System (INIS)

    George, R.P.; Anandkumar, B.; Vanithakumari, S.C.; Kamachi Mudali, U.

    2016-01-01

    Effectiveness of cooling water systems in various power plants to maintain highest electrical energy output per tonne of fuel is important as part of good energy management. Cooling water systems of nuclear power plants using seawater for cooling comes under constant attack from the marine and sea water environment. Many metallic components and civil structures in the cooling water systems like bridges, intake wells, intake pipes, pump house wells, water boxes, condenser pipes are subjected to severe fouling and corrosion which limits the service life and availability of power plants. The experience with a coastal water cooled power plant at Kalpakkam (MAPS), India, showed that chlorination and screening control macrofouling to a great extend by controlling protozoans, invertebrates, algae and fungi. However 90% of marine bacteria are resistant to such control measures, and they cause microfouling of condenser pipes leading to poor heat transfer and microbially influenced corrosion (MIC) failures. Titanium is used as condenser for Indian nuclear power plants employing sea water cooling, including the PFBR at Kalpakkam. Though titanium is excellent with respect to corrosion behavior under sea water conditions, its biocompatible nature results in biofouling and MIC during service. Therefore innovative antifouling coatings and surface modification techniques for titanium condenser applications in seawater and marine environments are the need of the hour. Extensive investigations were carried out by different methods including nanostructuring of surfaces for making them antibacterial. The microroughness of titanium was produced by repeated pickling and polishing which by itself reduced microbial adhesion. To utilize photocatalytic activity for antibacterial property, anodization of titanium surfaces followed by heat treatment was adopted and this also has controlled microbial fouling. Electroless plating of nanofilm of copper-nickel alloy decreased biofouling of

  20. Epifauna dynamics at an offshore foundation--implications of future wind power farming in the North Sea.

    Science.gov (United States)

    Krone, Roland; Gutow, Lars; Joschko, Tanja J; Schröder, Alexander

    2013-04-01

    In the light of the introduction of thousands of large offshore wind power foundations into the North Sea within the next decades, this manuscript focuses on the biofouling processes and likely reef effects. The study explores the macrozoobenthos (biofouling) colonization at an offshore platform which is comparable to offshore wind turbine foundations. A total of 183 single samples were taken and the parameters water depth and time were considered comparing biofouling masses and communities. The blue mussel Mytilus edulis, Anthozoa and the Amphipoda Jassa spp. were the dominant species. The community from the 1 m zone and those from the 5 and 20-28 m zones can clearly be differentiated. The 10 m zone community represents the transition between the M. edulis dominated 1 m and 5 m zones and the Anthozoa dominated 20-28 m zone. In the future offshore wind farms, thousands of wind turbine foundations will provide habitat for a hard bottom fauna which is otherwise restricted to the sparse rocky habitats scattered within extensive sedimentary soft bottoms of the German Bight. However, offshore wind power foundations cannot be considered natural rock equivalents as they selectively increase certain natural hard bottom species. The surface of the construction (1280 m²) was covered by an average of 4300 kg biomass. This foundation concentrates on its footprint area (1024 m²) 35 times more macrozoobenthos biomass than the same area of soft bottom in the German exclusive economic zone (0.12 kg m(-2)), functioning as a biomass hotspot. Concerning the temporal biomass variation, we assume that at least 2700 kg biomass was exported on a yearly basis. 345 × 10(4) single mussel shells of different sizes were produced during the study period. It is anticipated that the M. edulis abundance will increase in the North Sea due to the expansion of the offshore wind farm development. This will result in the enhanced production of secondary hard substrate (mussel shells

  1. Development and characterization of 3D-printed feed spacers for spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber

    2016-01-02

    Feed spacers are important for the impact of biofouling on the performance of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane systems. The objective of this study was to propose a strategy for developing, characterizing, and testing of feed spacers by numerical modeling, three-dimensional (3D) printing of feed spacers and experimental membrane fouling simulator (MFS) studies. The results of numerical modeling on the hydraulic behavior of various feed spacer geometries suggested that the impact of spacers on hydraulics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating that modeling can serve as first step in spacer characterization. An experimental comparison study of a feed spacer currently applied in practice and a 3D printed feed spacer with the same geometry showed (i) similar hydraulic behavior, (ii) similar pressure drop development with time and (iii) similar biomass accumulation during MFS biofouling studies, indicating that 3D printing technology is an alternative strategy for development of thin feed spacers with a complex geometry. Based on the numerical modeling results, a modified feed spacer with low pressure drop was selected for 3D printing. The comparison study of the feed spacer from practice and the modified geometry 3D printed feed spacer established that the 3D printed spacer had (i) a lower pressure drop during hydraulic testing, (ii) a lower pressure drop increase in time with the same accumulated biomass amount, indicating that modifying feed spacer geometries can reduce the impact of accumulated biomass on membrane performance. The combination of numerical modeling of feed spacers and experimental testing of 3D printed feed spacers is a promising strategy (rapid, low cost and representative) to develop advanced feed spacers aiming to reduce the impact of biofilm formation on

  2. Non-Leaching, Benign Antifouling Multilayer Polymer Coatings for Marine Applications

    Science.gov (United States)

    2010-03-01

    oriented. It is caused by the accumulation and settlement of barnacles, macroalgae, microbial slimes, and other micro and macro scale organisms on man...figure 12) (10, 11). Glass test slides for biofouling tests of the green alga Ulva were soaked in a 30 mL tank of recirculating deionized water at...on the experimental coatings was compared with the settlement rates of the controls. Barnacles are then cultivated to a mature size (over two to four

  3. Highly Specific Binding on Antifouling Zwitterionic Polymer-Coated Microbeads as Measured by Flow Cytometry.

    Science.gov (United States)

    van Andel, Esther; de Bus, Ian; Tijhaar, Edwin J; Smulders, Maarten M J; Savelkoul, Huub F J; Zuilhof, Han

    2017-11-08

    Micron- and nano-sized particles are extensively used in various biomedical applications. However, their performance is often drastically hampered by the nonspecific adsorption of biomolecules, a process called biofouling, which can cause false-positive and false-negative outcomes in diagnostic tests. Although antifouling coatings have been extensively studied on flat surfaces, their use on micro- and nanoparticles remains largely unexplored, despite the widespread experimental (specifically, clinical) uncertainties that arise because of biofouling. Here, we describe the preparation of magnetic micron-sized beads coated with zwitterionic sulfobetaine polymer brushes that display strong antifouling characteristics. These coated beads can then be equipped with recognition elements of choice, to enable the specific binding of target molecules. First, we present a proof of principle with biotin-functionalized beads that are able to specifically bind fluorescently labeled streptavidin from a complex mixture of serum proteins. Moreover, we show the versatility of the method by demonstrating that it is also possible to functionalize the beads with mannose moieties to specifically bind the carbohydrate-binding protein concanavalin A. Flow cytometry was used to show that thus-modified beads only bind specifically targeted proteins, with minimal/near-zero nonspecific protein adsorption from other proteins that are present. These antifouling zwitterionic polymer-coated beads, therefore, provide a significant advancement for the many bead-based diagnostic and other biosensing applications that require stringent antifouling conditions.

  4. Multifunctional methacrylate-based coatings for glass and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pospiech, Doris, E-mail: pospiech@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Jehnichen, Dieter [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Starke, Sandra; Müller, Felix [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Technische Universität Dresden, Organic Chemistry of Polymers, Dresden (Germany); Bünker, Tobias [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Wollenberg, Anne [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Technische Universität Dresden, Organic Chemistry of Polymers, Dresden (Germany); Häußler, Liane; Simon, Frank; Grundke, Karina; Oertel, Ulrich [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Opitz, Michael; Kruspe, Rainer [IDUS Biologisch Analytisches Umweltlabor GmbH, Ottendorf-Okrilla (Germany)

    2017-03-31

    Highlights: • New methacrylate-based copolymers synthesized by free radical polymerization. • Comonomer AAMA was able to complex Cu (II) ions in solvent annealing procedure. • Coatings had efficient anti-biofouling efficacy. - Abstract: In order to prevent freshwater biofouling glass and metal surfaces were coated with novel transparent methacrylate-based copolymers. The multifunctionality of the copolymers, such as adhesion to the substrate, surface polarity, mechanical long-term stability in water, and ability to form metal complexes was inserted by the choice of suitable comonomers. The monomer 2-acetoacetoxy ethyl methacrylate (AAMA) was used as complexing unit to produce copper(II) complexes in the coating’s upper surface layer. The semifluorinated monomer 1H,1H,2H,2H-perfluorodecyl methacrylate was employed to adjust the surface polarity and wettability. Comprehensive surface characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that surface compositions and properties can be easily adjusted by varying the concentrations of the comonomers. The formation of copper(II) complexes along the copolymer chains and their stability against washing out with plenty of water was proven by XPS. Copolymers containing semifluorinated comonomers significantly inhibited the growth of Achnanthidium species. Copolymers with copper-loaded AAMA-sequences were able to reduce both the growth of Achnanthidium spec. and Staphylococcus aureus.

  5. Control of invasive marine invertebrates: an experimental evaluation of the use of low salinity for managing pest corals (Tubastraea spp.).

    Science.gov (United States)

    Moreira, Patrícia L; Ribeiro, Felipe V; Creed, Joel C

    2014-01-01

    This study investigated the use of low salinity as a killing agent for the invasive pest corals Tubastraea coccinea and Tubastraea tagusensis (Dendrophylliidae). Experiments investigated the efficacy of different salinities, the effect of colony size on susceptibility and the influence of length of exposure. Experimental treatments of colonies were carried out in aquaria. Colonies were then fixed onto experimental plates and monitored in the field periodically over a period of four weeks. The killing effectiveness of low salinity depended on the test salinity and the target species, but was independent of colony size. Low salinity was fast acting and prejudicial to survival: discoloration, necrosis, fragmenting and sloughing, exposure of the skeleton and cover by biofoulers occurred post treatment. For T. tagusensis, 50% mortality (LC50) after three days occurred at eight practical salinity units (PSU); for T. coccinea the LC50 was 2 PSU. Exposure to freshwater for 45-120 min resulted in 100% mortality for T. tagusensis, but only the 120 min period was 100% effective in killing T. coccinea. Freshwater is now routinely used for the post-border management of Tubastraea spp. This study also provides insights as to how freshwater may be used as a routine biosecurity management tool when applied pre-border to shipping vectors potentially transporting non-indigenous marine biofouling species.

  6. Estudio de casos Aislamiento de bacterias del hierro y azufre como productoras de biodeterioro o corrosión anaeróbica en tuberías y daño a otros materiales

    Directory of Open Access Journals (Sweden)

    Virginia Montero Campos

    Full Text Available Los procesos de biodeterioro son reconocidos actualmente como una de las mayores causas de deterioro en superficies de diversos materiales, queafectan a una gran cantidad y diversos tipos de industrias. Una superficie metálica en contacto con agua o tierra experimenta una serie de cambios biológicos e inorgánicos que constituyen el fouling. La posterior secuencia de cambios biológicos es debido a la adherencia irreversible de diferentes tipos de microorganismos sobre el metal a través del material polimérico extracelular, constituyendo ello, el biofouling. La biocorrosión y el biofouling de las superficies se deben a procesos biológicos y electroquímicos que ocurren mediante la participación de microorganismos adheridos a las superficies a través de biofilmes. Estas películas biológicas modifican las condiciones de la interfase metal/solución, formando una barrera al contacto entre el metal o material y el medio circundante, se considera que la corrosión microbiológica transcurre entonces sobre una superficie modificada con características fisicoquímicas y biológicas muy particulares y condicionadas, donde no se puede interpretar con los mismos parámetros de un proceso de corrosión inorgánica.

  7. Transcriptome and Proteome Studies Reveal Candidate Attachment Genes during the Development of the Barnacle Amphibalanus Amphitrite

    KAUST Repository

    Al-Aqeel, Sarah; Ryu, Tae Woo; Zhang, Huoming; Chandramouli, Kondethimmanahalli; Ravasi, Timothy

    2016-01-01

    The acorn barnacle, Balanus amphitrite, is the main biofouling organism in marine environments. In the present study we profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI, and cyprid) from the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41%. We identified 65,784 expressed contigs, and a total of 1387 expressed proteins measured by quantitative proteomics. We found that osmotic stress, salt stress, hyperosmotic response and the Wnt signaling pathway were strongly up-regulated during the planktonic stage, while the MAPK pathway, lipid metabolism, and cuticle development genes were down-regulated. In the transition stage between the nauplius VI and the cyprid, genes that are involved in blood coagulation, cuticle development and eggshell formation were highly up-regulated, while the nitric oxide pathway, which stimulates the swimming and feeding response in marine invertebrates, was down-regulated. We are able to report for the first time that sound sensory system proteins are highly abundant in the nauplius VI stage, implying that these proteins are good targets for the development of new antifouling compounds. The results presented here together with the new genome-wide datasets for a non-model specie represent an important resource for the study of biofouling and development. Proteomics data are available via ProteomeXchange with identifier PXD004679.

  8. Synthesis and extracellular accumulation of silver nanoparticles by employing radiation-resistant Deinococcus radiodurans, their characterization, and determination of bioactivity

    Directory of Open Access Journals (Sweden)

    Kulkarni RR

    2015-01-01

    Full Text Available Rasika R Kulkarni, Nayana S Shaiwale, Dileep N Deobagkar, Deepti D Deobagkar Molecular Biology Research Laboratory, Center of Advanced Studies, Department of Zoology, University of Pune, Pune, India Abstract: There has been rapid progress in exploring microorganisms for green synthesis of nanoparticles since microbes show extraordinary diversity in terms of species richness and niche localization. Microorganisms are easy to culture using relatively inexpensive and simple nutrients under varied conditions of temperature, pressure, pH, etc. In this work, Deinococcus radiodurans that possesses the ability to withstand extremely high radiation and desiccation stress has been employed for the synthesis of silver nanoparticles (AgNPs. D. radiodurans was able to accumulate AgNPs in medium under various conditions, and process optimization was carried out with respect to time, temperature, pH, and concentration of silver salt. AgNPs were characterized using UV/vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The microbially synthesized AgNPs exhibited good antimicrobial activity against both Gram-negative and Gram-positive organisms and anti-biofouling activity. Their ability to inhibit growth and proliferation of cancer cell line was also examined, and it could be seen that AgNPs synthesized using D. radiodurans exhibited excellent anticancer activity. Keywords: Deinococcus radiodurans, silver nanoparticles, anticancer, radiation resistance, antibacterial, anti-biofouling 

  9. Multifunctional methacrylate-based coatings for glass and metal surfaces

    International Nuclear Information System (INIS)

    Pospiech, Doris; Jehnichen, Dieter; Starke, Sandra; Müller, Felix; Bünker, Tobias; Wollenberg, Anne; Häußler, Liane; Simon, Frank; Grundke, Karina; Oertel, Ulrich; Opitz, Michael; Kruspe, Rainer

    2017-01-01

    Highlights: • New methacrylate-based copolymers synthesized by free radical polymerization. • Comonomer AAMA was able to complex Cu (II) ions in solvent annealing procedure. • Coatings had efficient anti-biofouling efficacy. - Abstract: In order to prevent freshwater biofouling glass and metal surfaces were coated with novel transparent methacrylate-based copolymers. The multifunctionality of the copolymers, such as adhesion to the substrate, surface polarity, mechanical long-term stability in water, and ability to form metal complexes was inserted by the choice of suitable comonomers. The monomer 2-acetoacetoxy ethyl methacrylate (AAMA) was used as complexing unit to produce copper(II) complexes in the coating’s upper surface layer. The semifluorinated monomer 1H,1H,2H,2H-perfluorodecyl methacrylate was employed to adjust the surface polarity and wettability. Comprehensive surface characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that surface compositions and properties can be easily adjusted by varying the concentrations of the comonomers. The formation of copper(II) complexes along the copolymer chains and their stability against washing out with plenty of water was proven by XPS. Copolymers containing semifluorinated comonomers significantly inhibited the growth of Achnanthidium species. Copolymers with copper-loaded AAMA-sequences were able to reduce both the growth of Achnanthidium spec. and Staphylococcus aureus.

  10. Anti-corrosive and anti-microbial properties of nanocrystalline Ni-Ag coatings

    Energy Technology Data Exchange (ETDEWEB)

    Raghupathy, Y.; Natarajan, K.A.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in

    2016-04-15

    Graphical abstract: - Highlights: • Electrodeposition yielded phase-segregated, nanocrystalline Ni-Ag coatings. • Ni-Ag alloys exhibited smaller Ni crystals compared to pure Ni. • Ultra fine Ni grains of size 12–14 nm favoured Ni-Ag solid solution. • Nanocrystalline Ag resisted bio-fouling by Sulphate Reducing bacteria. • Ni-Ag outperformed pure Ni in corrosion and bio-corrosion tests. - Abstract: Anti-corrosive and anti-bacterial properties of electrodeposited nanocrystalline Ni-Ag coatings are illustrated. Pure Ni, Ni-7 at.% Ag, & Ni-14 at.% Ag coatings were electrodeposited on Cu substrate. Coating consisted of Ni-rich and Ag-rich solid solution phases. With increase in the Ag content, the corrosion resistance of the Ni-Ag coating initially increased and then decreased. The initial increase was due to the Ni-Ag solid solution. The subsequent decrease was due to the increased galvanic coupling between the Ag-rich and Ni-rich phases. For all Ag contents, the corrosion resistance of the Ni-Ag coating was higher than the pure Ni coating. Exposure to Sulphate Reducing Bacteria (SRB) revealed that the extent of bio-fouling decreased with increase in the Ag content. After 2 month exposure to SRB, the Ni-Ag coatings demonstrated less loss in corrosion resistance (58% for Ni-7 at.% Ag and 20% for Ni-14 at.% Ag) when compared pure Ni coating (115%).

  11. Transcriptome and proteome studies reveal candidate attachment genes during the development of the barnacle Amphibalanus Amphitrite

    Directory of Open Access Journals (Sweden)

    Sarah Al-Aqeel

    2016-09-01

    Full Text Available The acorn barnacle, Balanus amphitrite, is the main biofouling organism in marine environments. In the present study we profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI and cyprid from the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41‰. We identified 65,784 expressed contigs, and a total of 1,387 expressed proteins measured by quantitative proteomics. We found that osmotic stress, salt stress, hyperosmotic response and the Wnt signaling pathway were strongly up-regulated during the planktonic stage, while the MAPK pathway, lipid metabolism, and cuticle development genes were down-regulated. In the transition stage between the nauplius VI and the cyprid, genes that are involved in blood coagulation, cuticle development and eggshell formation were highly up-regulated, while the nitric oxide pathway, which stimulates the swimming and feeding response in marine invertebrates, was down-regulated. We are able to report for the first time that sound sensory system proteins are highly abundant in the nauplius VI stage, implying that these proteins are good targets for the development of new antifouling compounds. The results presented here together with the new genome-wide datasets for a non-model specie represent an important resource for the study of biofouling and development.

  12. A novel approach for UV-patterning with binary polymer brushes.

    Science.gov (United States)

    Li, Lifu; Nakaji-Hirabayashi, Tadashi; Kitano, Hiromi; Ohno, Kohji; Saruwatari, Yoshiyuki; Matsuoka, Kazuyoshi

    2018-01-01

    A mixed self-assembled monolayer (SAM) of an initiator (3-(2-bromo-2-isobutyryloxy)propyl triethoxysilane) for atom transfer radical polymerization (ATRP) and an agent (6-(triethoxysilyl)hexyl 2-(((methylthio)carbonothioyl)thio)-2-phenylacetate) for reversible addition-fragmentation chain transfer (RAFT) polymerization was constructed on the surface of a silicon wafer or glass plate by a silane coupling reaction. When a UV light at 254nm was irradiated at the mixed SAM through a photomask, the surface density of the bromine atom at the end of BPE in the irradiated region was drastically reduced by UV-driven scission of the BrC bond, as observed by X-ray photoelectron spectroscopy. Consequently, the surface-initiated (SI)-ATRP of 2-ethylhexyl methacrylate (EHMA) was used to easily construct the poly(EHMA) (PEHMA) brush domain. Subsequently, SI-RAFT polymerization of a zwitterionic vinyl monomer, carboxymethyl betaine (CMB), was performed. Using the sequential polymerization, the PCMB and PEHMA brush domains on the solid substrate could be very easily patterned. Patterning proteins and cells with the binary polymer brush is expected because the PCMB brush indicated strong suppression of protein adsorption and cell adhesion, and the PEHMA brush had non-polar properties. This technique is very simple and useful for regulating the shape and size of bio-fouling and anti-biofouling domains on solid surfaces. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Construction and validation of a long-channel membrane test cell for representative monitoring of performance and characterization of fouling over the length of spiral-wound membrane modules

    KAUST Repository

    Siebdrath, Nadine

    2017-12-03

    A long-channel membrane test cell (LCMTC) with the same length as full-scale elements was developed to simulate performance and fouling in nanofiltration and reverse osmosis spiral-wound membrane modules (SWMs). The transparent LCMTC enabled simultaneous monitoring of SWM performance indicators: feed channel pressure drop, permeate flux and salt passage. Both permeate flux and salt passage were monitored over five sections of the test cell and were related to the amount and composition of the accumulated foulant in these five sections, illustrating the unique features of the test cell. Validation experiments at various feed pressures showed the same flow profile and the same hydraulic behaviour as SWMs used in practice, confirming the representativeness and suitability of the test cell to study SWM operation and fouling. The importance to apply feed spacers matching the flow channel height in test cell systems was demonstrated. Biofouling studies showed that the dosage of a biodegradable substrate to the feed of the LCMTC accelerated the gradual decrease of membrane performance and the accumulation of biomass on the spacer and membrane sheets. The strongest permeate flux decline and the largest amount of accumulated biomass was found in the first 18 cm of the test cell. The LCMTC showed to be suitable to study the impact of biofilm development and biofouling control strategies under representative conditions for full-scale membrane elements.

  14. Transcriptome and Proteome Studies Reveal Candidate Attachment Genes during the Development of the Barnacle Amphibalanus Amphitrite

    KAUST Repository

    Al-Aqeel, Sarah

    2016-09-21

    The acorn barnacle, Balanus amphitrite, is the main biofouling organism in marine environments. In the present study we profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI, and cyprid) from the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41%. We identified 65,784 expressed contigs, and a total of 1387 expressed proteins measured by quantitative proteomics. We found that osmotic stress, salt stress, hyperosmotic response and the Wnt signaling pathway were strongly up-regulated during the planktonic stage, while the MAPK pathway, lipid metabolism, and cuticle development genes were down-regulated. In the transition stage between the nauplius VI and the cyprid, genes that are involved in blood coagulation, cuticle development and eggshell formation were highly up-regulated, while the nitric oxide pathway, which stimulates the swimming and feeding response in marine invertebrates, was down-regulated. We are able to report for the first time that sound sensory system proteins are highly abundant in the nauplius VI stage, implying that these proteins are good targets for the development of new antifouling compounds. The results presented here together with the new genome-wide datasets for a non-model specie represent an important resource for the study of biofouling and development. Proteomics data are available via ProteomeXchange with identifier PXD004679.

  15. Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling.

    Science.gov (United States)

    Iorhemen, Oliver Terna; Hamza, Rania Ahmed; Tay, Joo Hwa

    2016-06-15

    The membrane bioreactor (MBR) has emerged as an efficient compact technology for municipal and industrial wastewater treatment. The major drawback impeding wider application of MBRs is membrane fouling, which significantly reduces membrane performance and lifespan, resulting in a significant increase in maintenance and operating costs. Finding sustainable membrane fouling mitigation strategies in MBRs has been one of the main concerns over the last two decades. This paper provides an overview of membrane fouling and studies conducted to identify mitigating strategies for fouling in MBRs. Classes of foulants, including biofoulants, organic foulants and inorganic foulants, as well as factors influencing membrane fouling are outlined. Recent research attempts on fouling control, including addition of coagulants and adsorbents, combination of aerobic granulation with MBRs, introduction of granular materials with air scouring in the MBR tank, and quorum quenching are presented. The addition of coagulants and adsorbents shows a significant membrane fouling reduction, but further research is needed to establish optimum dosages of the various coagulants/adsorbents. Similarly, the integration of aerobic granulation with MBRs, which targets biofoulants and organic foulants, shows outstanding filtration performance and a significant reduction in fouling rate, as well as excellent nutrients removal. However, further research is needed on the enhancement of long-term granule integrity. Quorum quenching also offers a strong potential for fouling control, but pilot-scale testing is required to explore the feasibility of full-scale application.

  16. Construction and validation of a long-channel membrane test cell for representative monitoring of performance and characterization of fouling over the length of spiral-wound membrane modules

    KAUST Repository

    Siebdrath, Nadine; Ding, Wei; Pietsch, Elisabeth; Kruithof, Joop; Uhl, Wolfgang; Vrouwenvelder, Johannes S.

    2017-01-01

    A long-channel membrane test cell (LCMTC) with the same length as full-scale elements was developed to simulate performance and fouling in nanofiltration and reverse osmosis spiral-wound membrane modules (SWMs). The transparent LCMTC enabled simultaneous monitoring of SWM performance indicators: feed channel pressure drop, permeate flux and salt passage. Both permeate flux and salt passage were monitored over five sections of the test cell and were related to the amount and composition of the accumulated foulant in these five sections, illustrating the unique features of the test cell. Validation experiments at various feed pressures showed the same flow profile and the same hydraulic behaviour as SWMs used in practice, confirming the representativeness and suitability of the test cell to study SWM operation and fouling. The importance to apply feed spacers matching the flow channel height in test cell systems was demonstrated. Biofouling studies showed that the dosage of a biodegradable substrate to the feed of the LCMTC accelerated the gradual decrease of membrane performance and the accumulation of biomass on the spacer and membrane sheets. The strongest permeate flux decline and the largest amount of accumulated biomass was found in the first 18 cm of the test cell. The LCMTC showed to be suitable to study the impact of biofilm development and biofouling control strategies under representative conditions for full-scale membrane elements.

  17. Measurement of Near-Surface Salinity, Temperature and Directional Wave Spectra using a Novel Wave-Following, Lagrangian Surface Contact Buoy

    Science.gov (United States)

    Boyle, J. P.

    2016-02-01

    Results from a surface contact drifter buoy which measures near-surface conductivity ( 10 cm depth), sea state characteristics and near-surface water temperature ( 2 cm depth) are described. This light (righting. It has a small above-surface profile and low windage, resulting in near-Lagrangian drift characteristics. It is autonomous, with low power requirements and solar panel battery recharging. Onboard sensors include an inductive toroidal conductivity probe for salinity measurement, a nine-degrees-of-freedom motion package for derivation of directional wave spectra and a thermocouple for water temperature measurement. Data retrieval for expendable, ocean-going operation uses an onboard Argos transmitter. Scientific results as well as data processing algorithms are presented from laboratory and field experiments which support qualification of buoy platform measurements. These include sensor calibration experiments, longer-term dock-side biofouling experiments during 2013-2014 and a series of short-duration ocean deployments in the Gulf Stream in 2014. In addition, a treatment method will be described which appears to minimize the effects of biofouling on the inductive conductivity probe when in coastal surface waters. Due to its low cost and ease of deployment, scores, perhaps hundreds of these novel instruments could be deployed from ships or aircraft during process studies or to provide surface validation for satellite-based measurements, particularly in high precipitation regions.

  18. Inhibition of biofilm formation by D-tyrosine: Effect of bacterial type and D-tyrosine concentration.

    Science.gov (United States)

    Yu, Cong; Li, Xuening; Zhang, Nan; Wen, Donghui; Liu, Charles; Li, Qilin

    2016-04-01

    D-Tyrosine inhibits formation and triggers disassembly of bacterial biofilm and has been proposed for biofouling control applications. This study probes the impact of D-tyrosine in different biofilm formation stages in both G+ and G- bacteria, and reveals a non-monotonic correlation between D-tyrosine concentration and biofilm inhibition effect. In the attachment stage, cell adhesion was studied in a flow chamber, where D-tyrosine caused significant reduction in cell attachment. Biofilms formed by Pseudomonas aeruginosa and Bacillus subtilis were characterized by confocal laser scanning microscopy as well as quantitative analysis of cellular biomass and extracellular polymeric substances. D-Tyrosine exhibited strong inhibitive effects on both biofilms with an effective concentration as low as 5 nM; the biofilms responded to D-tyrosine concentration change in a non-monotonic, bi-modal pattern. In addition, D-tyrosine showed notable and different impact on EPS production by G+ and G- bacteria. Extracellular protein was decreased in P. aeruginosa biofilms, but increased in those of B. subtilis. Exopolysaccharides production by P. aeruginosa was increased at low concentrations and reduced at high concentrations while no impact was found in B. subtilis. These results suggest that distinct mechanisms are at play at different D-tyrosine concentrations and they may be species specific. Dosage of D-tyrosine must be carefully controlled for biofouling control applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Algal epibiosis on Megabalanus tintinnabulum and its role in segregation of the Balanus amphitrite population

    Digital Repository Service at National Institute of Oceanography (India)

    Eswaran, R.; Khandeparker, L.

    & BPA were maintained on ZMA and BPA slants as described by Konya et al. (1995). The isolated bacteria (Table I) were identified following ‘Bergey’s manual of systematic bacteriology (Holt et al. 1994) and manual for the identification of medical... of barnacle settlement pheromones. Biofouling, 15, 57–71. Cowan S.T. (1974) Cowan and steel’s manual for the identification of medical bacteria. 2nd edition, Cambridge University press, Cambridge: 238pp. Desai D.V., Anil A.C. (2005) Recruitment...

  20. Hydroacoustic Antifouling Systems

    OpenAIRE

    D'Hoore, S.; De Vuyst, T.; De Vos, L.; Dobbelaere, A.

    2017-01-01

    Biofouling has a major impact on the global shipping industry. The fouling demands extensive efforts to clean the fouled vessels, increases the expenses for the shipping companies and worsens a number of environmental problems, such as carbon dioxide emissions due to increased drag, or the transport of organisms outside their habitat. In the past, toxic paints were found to be the solution for this problem. The ban of TBT (tributyltin), because of its negative impact on the environment, has l...