WorldWideScience

Sample records for technlogies reverse osmosis

  1. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  2. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  3. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  4. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  5. Reverse osmosis water purification system

    Science.gov (United States)

    Ahlstrom, H. G.; Hames, P. S.; Menninger, F. J.

    1986-01-01

    A reverse osmosis water purification system, which uses a programmable controller (PC) as the control system, was designed and built to maintain the cleanliness and level of water for various systems of a 64-m antenna. The installation operates with other equipment of the antenna at the Goldstone Deep Space Communication Complex. The reverse osmosis system was designed to be fully automatic; with the PC, many complex sequential and timed logic networks were easily implemented and are modified. The PC monitors water levels, pressures, flows, control panel requests, and set points on analog meters; with this information various processes are initiated, monitored, modified, halted, or eliminated as required by the equipment being supplied pure water.

  6. Reverse-osmosis membranes by plasma polymerization

    Science.gov (United States)

    Hollahan, J. R.; Wydeven, T.

    1972-01-01

    Thin allyl amine polymer films were developed using plasma polymerization. Resulting dry composite membranes effectively reject sodium chloride during reverse osmosis. Films are 98% sodium chloride rejective, and 46% urea rejective.

  7. Rotating Reverse-Osmosis for Water Purification

    Science.gov (United States)

    Lueptow, RIchard M.

    2004-01-01

    A new design for a water-filtering device combines rotating filtration with reverse osmosis to create a rotating reverse- osmosis system. Rotating filtration has been used for separating plasma from whole blood, while reverse osmosis has been used in purification of water and in some chemical processes. Reverse- osmosis membranes are vulnerable to concentration polarization a type of fouling in which the chemicals meant not to pass through the reverse-osmosis membranes accumulate very near the surfaces of the membranes. The combination of rotating filtration and reverse osmosis is intended to prevent concentration polarization and thereby increase the desired flux of filtered water while decreasing the likelihood of passage of undesired chemical species through the filter. Devices based on this concept could be useful in a variety of commercial applications, including purification and desalination of drinking water, purification of pharmaceutical process water, treatment of household and industrial wastewater, and treatment of industrial process water. A rotating filter consists of a cylindrical porous microfilter rotating within a stationary concentric cylindrical outer shell (see figure). The aqueous suspension enters one end of the annulus between the inner and outer cylinders. Filtrate passes through the rotating cylindrical microfilter and is removed via a hollow shaft. The concentrated suspension is removed at the end of the annulus opposite the end where the suspension entered.

  8. On the potential of forward osmosis to energetically outperform reverse osmosis desalination

    OpenAIRE

    McGovern, Ronan Killian; Lienhard, John H.

    2014-01-01

    We provide a comparison of the theoretical and actual energy requirements of forward osmosis and reverse osmosis seawater desalination. We argue that reverse osmosis is significantly more energy efficient and that forward osmosis research efforts would best be fully oriented towards alternate applications. The underlying reason for the inefficiency of forward osmosis is the draw-dilution step, which increases the theoretical and actual energy requirements for draw regeneration. As a consequen...

  9. 21 CFR 177.2550 - Reverse osmosis membranes.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Reverse osmosis membranes. 177.2550 Section 177... Components of Articles Intended for Repeated Use § 177.2550 Reverse osmosis membranes. Substances identified in paragraph (a) of this section may be safely used as reverse osmosis membranes intended for use...

  10. Boron Removal in Seawater Reverse Osmosis System

    KAUST Repository

    Rahmawati, Karina

    2011-07-01

    Reverse osmosis successfully proves to remove more than 99% of solute in seawater, providing fresh water supply with satisfied quality. Due to some operational constraints, however, some trace contaminants removal, such as boron, cannot be achieved in one pass system. The stringent criterion for boron from World Health Organization (WHO) and Saudi Arabia local standard (0.5 mg/l) is hardly fulfilled by single pass sea water reverse osmosis (SWRO) plants. Some design processes have been proposed to deal with boron removal, but they are not economically efficient due to high energy and chemical consumption. The objective of this study was to study boron removal by different reverse osmosis membranes in two pH conditions, with and without antiscalant addition. Thus, it was expected to observe the possibility of operating single pass system and necessity to operate two pass system using low energy membrane. Five membrane samples were obtained from two different manufacturers. Three types of feed water pH were used, pH 8, pH 10, and pH 10 with antiscalant addition. Experiment was conducted in parallel to compare membrane performance from two manufacturers. Filtration was run with fully recycle mode for three days. Sample of permeate and feed were taken every 12 hours, and analyzed for their boron and TDS concentration. Membrane samples were also tested for their surface charge. The results showed that boron rejection increases as the feed pH increases. This was caused by dissociation of boric acid to negatively charged borate ion and more negatively charged membrane surface at elevated pH which enhance boron rejection. This study found that single pass reverse osmosis system, with and without elevating the pH, may not be possible to be applied because of two reasons. First, permeate quality in term of boron, does not fulfill WHO and local Saudi Arabia regulations. Second, severe scaling occurs due to operation in alkaline condition, since Ca and Mg concentration are

  11. A Reverse Osmosis System for an Advanced Separation Process Laboratory.

    Science.gov (United States)

    Slater, C. S.; Paccione, J. D.

    1987-01-01

    Focuses on the development of a pilot unit for use in an advanced separations process laboratory in an effort to develop experiments on such processes as reverse osmosis, ultrafiltration, adsorption, and chromatography. Discusses reverse osmosis principles, the experimental system design, and some experimental studies. (TW)

  12. Open-source CFD model for optimization of forward osmosis and reverse osmosis membrane modules

    DEFF Research Database (Denmark)

    Gruber, Mathias Felix; Aslak, Ulf; Hélix-Nielsen, Claus

    2016-01-01

    Osmotic membrane separation processes are based on using semi-permeable membranes to remove solutes from a given feed solution. This can happen either as Reverse Osmosis (RO) where a hydraulic pressure is applied to drive separation across the membrane, or as Forward Osmosis (FO) where osmotic pr...

  13. Reverse osmosis desalination: water sources, technology, and today's challenges.

    Science.gov (United States)

    Greenlee, Lauren F; Lawler, Desmond F; Freeman, Benny D; Marrot, Benoit; Moulin, Philippe

    2009-05-01

    Reverse osmosis membrane technology has developed over the past 40 years to a 44% share in world desalting production capacity, and an 80% share in the total number of desalination plants installed worldwide. The use of membrane desalination has increased as materials have improved and costs have decreased. Today, reverse osmosis membranes are the leading technology for new desalination installations, and they are applied to a variety of salt water resources using tailored pretreatment and membrane system design. Two distinct branches of reverse osmosis desalination have emerged: seawater reverse osmosis and brackish water reverse osmosis. Differences between the two water sources, including foulants, salinity, waste brine (concentrate) disposal options, and plant location, have created significant differences in process development, implementation, and key technical problems. Pretreatment options are similar for both types of reverse osmosis and depend on the specific components of the water source. Both brackish water and seawater reverse osmosis (RO) will continue to be used worldwide; new technology in energy recovery and renewable energy, as well as innovative plant design, will allow greater use of desalination for inland and rural communities, while providing more affordable water for large coastal cities. A wide variety of research and general information on RO desalination is available; however, a direct comparison of seawater and brackish water RO systems is necessary to highlight similarities and differences in process development. This article brings to light key parameters of an RO process and process modifications due to feed water characteristics.

  14. Rotating Reverse Osmosis for Wastewater Reuse

    Science.gov (United States)

    Lueptow, Richard M.; Yoon, Yeomin; Pederson, Cynthia

    2004-01-01

    Our previous work established the concept of a low-pressure rotating reverse osmosis membrane system. The rotation of the cylindrical RO filter produces shear and Taylor vortices in the annulus of the device that decrease the concentration polarization and fouling commonly seen with conventional RO filtration techniques. A mathematical model based on the film theory and the solution-diffusion model agrees well with the experimental results obtained using this first generation prototype. However, based on the model, the filtrate flux and contaminant rejection depend strongly on the transmembrane pressure. Therefore, the goal of our current work is to improve the flux of the device by increasing the transmembrane pressure by a factor of 3 to 4. In addition, the rejections for a wider variety of inorganic and organic compounds typically found in space mission wastewater are measured.

  15. Application of reverse osmosis membrane system for treatment of ...

    African Journals Online (AJOL)

    Application of reverse osmosis membrane system for treatment of effluent in textile knitted fabric dyeing. ... African Journal of Biotechnology ... The textile industry consumes a vast quantity of water and generates an equally vast quantity of ...

  16. Mass transfer properties of chlorinated aromatic polyamide reverse osmosis membranes

    OpenAIRE

    Ettori, Axel; Gaudichet-Maurin, Emmanuelle; Aimar, Pierre; Causserand, Christel

    2012-01-01

    International audience; Water (A) and solute (B) permeability of aromatic polyamide (PA) reverse osmosis membranes (RO) were monitored under varying applied pressure, solute nature and concentration to assess their evolution after exposure of the membrane to free chlorine. Above a threshold value of 400 ppm h HOCl water permeability was influenced by permeation conditions during both filtration of ultrapure water (UP water) and reverse osmosis of salts performed sequentially. Water permeabili...

  17. High pressure rotating reverse osmosis for long term space missions

    Science.gov (United States)

    Christensen Pederson, Cynthia Lynn

    Rotating reverse osmosis, which uses reverse osmosis to purify water and rotating filtration to improve the efficacy of filtration, has great potential for wastewater recycling on a long term space mission. Previous investigations of a proof-of-concept device indicated that the most efficient method to improve rotating reverse osmosis performance is to increase the operational pressure. Thus, a second generation device and fluid circuit were designed, fabricated, and tested to permit high pressure operation for long time periods. The design overcame several obstacles including membrane attachment, rotating seal design, and fluid and pressure management. A theoretical model of rotating reverse osmosis was modified to properly account for the flow conditions in the new design. Tests lasting a week were conducted with a variety of model wastewaters. Significant fouling and a decrease in flux were observed after three days of testing regardless of the operational parameters. A semi-empirical model, the fouling potential, was added to the theoretical model to account for the fouling. This allowed the simulation of 48 hour cleaning cycles that significantly increased the flux of the device. Experimental investigation of the rotational speed and concentrate flow rate indicated that an increase in either parameter decreased the fouling slightly. A week long test of a wastewater ersatz with a biocide did not exhibit a decrease in flux around day three that otherwise occurred. Therefore, biofouling was identified as the primary mechanism of fouling. Rotating reverse osmosis was compared with conventional spiral wound reverse osmosis and displayed increased rejection under dead end filtration conditions. The rotating device exhibited similar rejection and increased flux compared to a tubular reverse osmosis device previously used in a NASA wastewater recovery system. The integration of the rotating device into a NASA water recovery management system was evaluated. Lastly, a

  18. Novel technologies for reverse osmosis concentrate treatment: a review.

    Science.gov (United States)

    Joo, Sung Hee; Tansel, Berrin

    2015-03-01

    Global water shortages due to droughts and population growth have created increasing interest in water reuse and recycling and, concomitantly, development of effective water treatment processes. Pressured membrane processes, in particular reverse osmosis, have been adopted in water treatment industries and utilities despite the relatively high operational cost and energy consumption. However, emerging contaminants are present in reverse osmosis concentrate in higher concentrations than in the feed water, and have created challenges for treatment of the concentrate. Further, standards and guidelines for assessment and treatment of newly identified contaminants are currently lacking. Research is needed regarding the treatment and disposal of emerging contaminants of concern in reverse osmosis concentrate, in order to develop cost-effective methods for minimizing potential impacts on public health and the environment. This paper reviews treatment options for concentrate from membrane processes. Barriers to emerging treatment options are discussed and novel treatment processes are evaluated based on a literature review. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The concentrating of alizarin using a reverse osmosis process

    Directory of Open Access Journals (Sweden)

    S. S. MADAENI

    2005-02-01

    Full Text Available Membrane technologies in general and reverse osmosis in particular have been employed for the concentrating of solutions. In this study, the concentrating of a heat sensitive alizarin extracted from madder root was realized using an FT30 reverse osmosis membrane. The effects of cross flow velocity, transmembrane pressure and pH on the flux and rejection were studied. Increasing the transmembrane pressure increased the flux while the rejection was constant. At pH 7–8, the highest flux was achieved. This study showed that reverse osmosis is the process of choice for the concentrating of alizarin solutions. The optimum operating conditions were 1.0 m/s crossflow velocity, 16 bars transmembrane pressure and pH 7. The system was tested for 12 h without severe fouling problems.

  20. Hybrid membrane system for desalination and wastewater treatment: Integrating forward osmosis and low pressure reverse osmosis

    NARCIS (Netherlands)

    Valladares Linares, R.

    2014-01-01

    Since more than 97% of the water in the world is seawater, desalination technologies have the potential to solve the fresh water crisis. The most used desalination technology nowadays is seawater reverse osmosis (SWRO), where a membrane is used as a physical barrier to separate the salts from the wa

  1. Hybrid membrane system for desalination and wastewater treatment: Integrating forward osmosis and low pressure reverse osmosis

    NARCIS (Netherlands)

    Valladares Linares, R.

    2014-01-01

    Since more than 97% of the water in the world is seawater, desalination technologies have the potential to solve the fresh water crisis. The most used desalination technology nowadays is seawater reverse osmosis (SWRO), where a membrane is used as a physical barrier to separate the salts from the

  2. Improvement of water desalination technologies in reverse osmosis plants

    Science.gov (United States)

    Vysotskii, S. P.; Konoval'chik, M. V.; Gul'ko, S. E.

    2017-07-01

    The strengthening of requirements for the protection of surface-water sources and increases in the cost of reagents lead to the necessity of using membrane (especially, reverse osmosis) technologies of water desalination as an alternative to ion-exchange technologies. The peculiarities of using reverse osmosis technologies in the desalination of waters with an increased salinity have been discussed. An analogy has been made between the dependence of the adsorptive capacity of ion-exchange resins on the reagent consumption during ion exchange and the dependence of the specific ion flux on the voltage in the electrodialysis and productivity of membrane elements on the excess of the pressure of source water over the osmotic pressure in reverse osmosis. It has been proposed to regulate the number of water desalination steps in reverse osmosis plants, which makes it possible to flexibly change the productivity of equipment and the level of desalinization, depending on the requirements for the technological process. It is shown that the selectivity of reverse osmotic membranes with respect to bivalent ions (calcium, magnesium, and sulfates) is approximately four times higher than the selectivity with respect to monovalent ions (sodium and chlorine). The process of desalination in reverse osmosis plants depends on operation factors, such as the salt content and ion composition of source water, the salt content of the concentrate, and the temperatures of solution and operating pressure, and the design features of devices, such as the length of the motion of the desalination water flux, the distance between membranes, and types of membranes and turbulators (spacers). To assess the influence of separate parameters on the process of reverse osmosis desalination of water solutions, we derived criteria equations by compiling problem solution matrices on the basis of the dimensional method, taking into account the Huntley complement. The operation of membrane elements was

  3. Troubleshooting at Reverse Osmosis performance decrease

    Energy Technology Data Exchange (ETDEWEB)

    Soons, Jan [KEMA (Netherlands)

    2011-07-01

    There are several causes for a decrease in Reverse Osmosis (RO) membrane performance each of which requiring actions to tackle the possible cause. Two of the main factors affecting the performance of the system are the feed quality (poor feed quality can lead to fouling of the membranes) and the operational conditions (including the maximum allowed pressure, minimum cleaning frequencies and types, recovery rate etc, which should be according to the design conditions). If necessary, pre-treatment will be applied in order to remove the fouling agents from the influent, reduce scaling (through the addition of anti-scalants) and for the protection of the membranes (for example, sodium metabisulphite addition for the removal of residual chlorine which can harm the membranes). Fouling is not strictly limited to the use of surface water as feed water, also relatively clean water sources will, over time, lead to organic and inorganic fouling when cleaning is not optimum. When fouling occurs, the TransMembrane Pressure (TMP) increases and more energy will be needed to produce the same amount of product water. Also, the cleaning rate will increase, reducing the production rate and increasing the chemical consumption and the produced waste streams. Furthermore, the quality of the effluent will decrease (lower rejection rates at higher pressures) and the lifetime of the membranes will decrease. Depending on the type of fouling different cleaning regimes will have to be applied: acidic treatment for inorganic fouling, the addition of bases against organic fouling. Therefore, it is very important to have a clear view of the type of fouling that is occurring, in order to apply the correct treatment methods. Another important aspect to be kept in mind is that the chemistry of the water - in the first place ruled by the feed water composition - can change during passage of the modules, in particular in cases where the RO system consists of two or more RO trains, and where the

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

    Science.gov (United States)

    Maddah, Hisham; Chogle, Aman

    2016-10-01

    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.

  5. International overview of seawater desalination plant by reverse osmosis technology

    OpenAIRE

    Kangwen, Shu

    2012-01-01

    In a world faced with increased urbanization, population growth, climate change and degradation of water supplies, the importance of a reliable source of technology to provide fresh water emphasizes the importance of seawater desalination. Over the years a variety of seawater desalination methods have been developed throughout the world. The most common technologies available for desalination around the world are membrane reverse osmosis (RO), thermal distillation (TD) and electrodialysis ...

  6. Reverse osmosis membrane of high urea rejection properties. [water purification

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T. J. (Inventor)

    1980-01-01

    Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

  7. Real-Time Monitoring of Reverse Osmosis Membrane Integrity

    OpenAIRE

    Surawanvijit, Sirikarn

    2015-01-01

    Reverse osmosis (RO) membrane desalination is the primary technology for seawater and brackish water desalination, agricultural drainage desalting, as well as municipal wastewater recycling for potable water reuse applications. RO membranes achieve high salt rejection (>95%) and in principle should provide a complete physical barrier to nanosize pathogens (e.g., waterborne enteric viruses). However, in the presence of imperfections and/or membrane damage, membrane breaches as small as 20-30 n...

  8. Development and Extension of Seawater Desalination by Reverse Osmosis

    Institute of Scientific and Technical Information of China (English)

    高从堦

    2003-01-01

    Seawater desalination has been people's fond dream since ancient times, the dream isnow becoming a reality. This paper presents a brief development history of reverse osmosis. Muchattention was paid to innovative development in membranes, modules, equipments and appliedtechnology, including asymmetric and composite membranes, spiral-wound element and hollow fibermodule, energy recovery equipments and different technological processes. The extension of reverseosmosis, such as desalination, pre-concentration, integrated processes and nanofiltration, is alsobriefly mentioned.

  9. International overview of seawater desalination plant by reverse osmosis technology

    OpenAIRE

    Kangwen, Shu

    2012-01-01

    In a world faced with increased urbanization, population growth, climate change and degradation of water supplies, the importance of a reliable source of technology to provide fresh water emphasizes the importance of seawater desalination. Over the years a variety of seawater desalination methods have been developed throughout the world. The most common technologies available for desalination around the world are membrane reverse osmosis (RO), thermal distillation (TD) and electrodialysis ...

  10. IMPACTS OF REVERSE OSMOSIS ON SOUTHEAST MILK MARKETS

    OpenAIRE

    Schiek, William A.; Babb, Emerson M.

    1989-01-01

    The Southeast is a net importer of milk and milk products. Milk must be imported from other regions at certain times of the year. Reverse osmosis (RO) is a new processing technology which could significantly reduce milk transportation costs between regions by removing half the water from raw milk prior to shipment. A network flow algorithm, which incorporates federal milk orders and solves for the least cost procurement pattern, was used to assess the impact of RO on southeast milk marketing ...

  11. Modeling pH variation in reverse osmosis.

    Science.gov (United States)

    Nir, Oded; Bishop, Noga Fridman; Lahav, Ori; Freger, Viatcheslav

    2015-12-15

    The transport of hydronium and hydroxide ions through reverse osmosis membranes constitutes a unique case of ionic species characterized by uncommonly high permeabilities. Combined with electromigration, this leads to complex behavior of permeate pH, e.g., negative rejection, as often observed for monovalent ions in nanofiltration of salt mixtures. In this work we employed a rigorous phenomenological approach combined with chemical equilibrium to describe the trans-membrane transport of hydronium and hydroxide ions along with salt transport and calculate the resulting permeate pH. Starting from the Nernst-Planck equation, a full non-linear transport equation was derived, for which an approximate solution was proposed based on the analytical solution previously developed for trace ions in a dominant salt. Using the developed approximate equation, transport coefficients were deduced from experimental results obtained using a spiral wound reverse osmosis module operated under varying permeate flux (2-11 μm/s), NaCl feed concentrations (0.04-0.18 M) and feed pH values (5.5-9.0). The approximate equation agreed well with the experimental results, corroborating the finding that diffusion and electromigration, rather than a priori neglected convection, were the major contributors to the transport of hydronium and hydroxide. The approach presented here has the potential to improve the predictive capacity of reverse osmosis transport models for acid-base species, thereby improving process design/control.

  12. Behaviour of RO98pHt polyamide membrane in reverse osmosis and low reverse osmosis conditions for phenol removal.

    Science.gov (United States)

    Hidalgo, A M; León, G; Gómez, M; Murcia, M D; Gómez, E; Gómez, J L

    2011-10-01

    Phenolic compounds and their derivatives are very common pollutants in wastewaters. Among the methods described for their removal, pressure-driven membrane processes are considered as a reliable alternative. Our research group has previously studied phenol removal in reverse osmosis (RO) conditions and obtained very low rejection percentages. Subsequently, when low reverse osmosis (LRO) conditions were studied, the organic rejection percentages improved. To further our knowledge in this respect, the main objective of this work was to study the behaviour of the polyamide thin-film composite membrane RO98pHt used for phenol removal in RO and LRO conditions. The influence of different operating pressures, phenol feed concentrations and pH on permeate flux and phenol rejection was studied. Low reverse osmosis conditions led to higher phenol rejection percentages in all the assayed conditions, suggesting that other factors related to the molecular characteristics of the organic molecules, such as solubility, acidity and hydrogen bonding capacity, play an important role in the rejection percentage attained. As expected, permeate flux was greater in RO conditions.

  13. Characterization of Hemodialysis Reverse Osmosis Wastewater From Yazd Educational Hospitals

    Directory of Open Access Journals (Sweden)

    Mohammad Saleh Ali-Taleshi

    2016-05-01

    Full Text Available This paper evaluates the technical feasibility of reusing hemodialysis reverse osmosis wastewater from educational hospitals in Yazd, Iran, as an alternative water source. For this study, from October to December 2013, hemodialysis reverse osmosis wastewater samples were obtained from two dialysis facilities and analyzed for biochemical oxygen demand (BOD, chemical oxygen demand (COD, pH, and electrical conductivity (EC using standard methods. Furthermore, concentrations of heavy metals such as Ag, Ba, Cd, Cu, Pb, Se, and Zn were calculated. Results were analyzed using the one sample t-test and independent t-test in SPSS 16 software. Mean concentrations of Ag, Ba, Cd, Cu, Fe, Pb, Se, and Zn in the hemodialysis reverse osmosis wastewater were 0.0960, 0.0611, 0.0186, 0.3381, 0.2153, 0.2212, 0.4196, and 0.0667 mg/L at S. Dr. Rahnamoon hospital, and 0.0963, 0.0849, 0.0177, 0.2942, 0.2160, 0.1827, 0.3420, and 0.0867 mg/L at S. Sadoughi hospital, respectively. The results also showed that the important challenges for reusing hemodialysis wastewater were its high EC and the presence of some elements, such as Se and Pb. Unlike Se and Pb, the concentrations of the other parameters were below discharge emission standards. Because of the large volumes of water used in hemodialysis, it is important to study the potential for reusing or recycling it. Through evaluation of the technical feasibility of hemodialysis wastewater reuse, this study draws attention to this neglected issue, especially in hemodialysis therapy.

  14. Removal of chromium from wastewater by reverse osmosis

    Science.gov (United States)

    Çimen, Aysel

    2015-07-01

    Removal of chromium from wastewaters has been studied and the optimal process conditions were determined. The reverse osmosis (RO) technique, the sea water high rejection (SWHR) and high rejection brackish water (AG, SE, and SG) membranes were used. The chromium rejection depended on membrane type, pH of the feed water and operating pressure. The removal of chromium was most effective when the feed water pH 3. The rejection efficiency of the membranes increased in the order AG > SWHR > SG > SE. RO method can be efficiently used (with >91% rejection) for the removal of chromium from wastewater of chromium coating processes.

  15. Heuristic analysis of brackishwater treatment by reverse osmosis process

    OpenAIRE

    Ahmed, S

    1990-01-01

    Treatment of brackish water and sea water with the help of reverse osmosis process is feasible and a viable solution to meet the fresh water deficiency in an arid region. Total dissolved solids can be reduced to a level acceptable for drinking water. High purity water for industrial uses can also be obtained with the application of the RO process. Useful materials may also be recovered from the reject water. RO plants of various sizes (both large and small) have been in operation successfully...

  16. Optimization of membrane elements' array in industrial reverse osmosis units

    Science.gov (United States)

    Bobinkin, V. V.; Larionov, S. Yu.; Panteleev, A. A.; Shapovalov, D. A.; Shilov, M. M.

    2015-10-01

    It is stated that membrane elements, due to axial concentration and flow exhaustion during filtration, work in different operation conditions that differ according to various characteristics. Designing of multistage units is based on technical characteristics' identity of all membrane elements. It is explored that the difference in individual characteristics of membrane elements can take place. This can essentially affect the operation characteristics of a whole industrial unit. Particularly, it could lead to degradation of the permeate quality and the unit performance. Research on packaging the membrane elements in reverse osmosis units has shown that a simple replacement of membrane elements without the consideration of the individual characteristics can degrade the performance characteristics and affect the constancy of the unit operation. An optimization system of membrane elements' array was suggested to solve these problems and to upgrade the performance of reverse osmosis plants. The first step of the system is determination of individual characteristics of membrane elements. For the calculations using the individualized data, it is suggested to use the method of approximate calculation and the balance equations for water flows (source water, permeate, and retentate), and for the concentrations of the dissolved solids. The suggested optimization system of a membrane elements' array allowed the configuration of the membrane elements in the housings of one stage in such a way that the symmetry of the flows and of the pressure difference was achieved. The optimum value of the performance and the selectivity was achieved considering the hydraulic characteristics in one stage.

  17. Reverse osmosis and nanofiltration of biologically treated leachate.

    Science.gov (United States)

    Kuusik, Aare; Pachel, Karin; Kuusik, Argo; Loigu, Enn; Tang, Walter Z

    2014-01-01

    Experiments of nano-filtration (NF) and reverse osmosis (RO) were conducted to remove most pollutants from the biological treated leachate. For example, the purified permeate after reverse osmosis treatment with spiral membranes reached effluent water quality as follows: COD of 57 mg O2/l, BOD7 of 35 mg O2/l, and suspended solid of 1 mg/l which satisfies the discharge standards in Estonia. For both RO and NF, conductivity can be reduced by 91% from 6.06 to 0.371 mS/cm by RO and 99% from 200 to 1 mS/cm by NF. To test the service life of the RO spiral membranes, the process was able to reduce chemical oxygen demand (COD) and biological oxygen demand (BOD) of biologically treated leachate by 97.9% and 93.2% even after 328 and 586 hours, respectively. However, only 39.0% and 21.7% reductions of Ptot and Ntot were achieved. As a result, neither RO (spiral membranes process) nor NF was able to reduce the total nitrogen (TN) to the required discharge limit of 15 mg/l.

  18. Comparison of the removal of hydrophobic trace organic contaminants by forward osmosis and reverse osmosis.

    Science.gov (United States)

    Xie, Ming; Nghiem, Long D; Price, William E; Elimelech, Menachem

    2012-05-15

    We compared the rejection behaviours of three hydrophobic trace organic contaminants, bisphenol A, triclosan and diclofenac, in forward osmosis (FO) and reverse osmosis (RO). Using erythritol, xylose and glucose as inert reference organic solutes and the membrane pore transport model, the mean effective pore size of a commercial cellulose-based FO membrane was estimated to be 0.74 nm. When NaCl was used as the draw solute, at the same water permeate flux of 5.4 L/m(2) h (or 1.5 μm/s), the adsorption of all three compounds to the membrane in the FO mode was consistently lower than that in the RO mode. Rejection of bisphenol A and diclofenac were higher in the FO mode compared to that in the RO mode. Because the molecular width of triclosan was larger than the estimated mean effective membrane pore size, triclosan was completely rejected by the membrane and negligent difference between the FO and RO modes could be observed. The difference in the separation behaviour of these hydrophobic trace organics in the FO (using NaCl the draw solute) and RO modes could be explained by the phenomenon of retarded forward diffusion of solutes. The reverse salt flux of NaCl hinders the pore diffusion and subsequent adsorption of the trace organic compounds within the membrane. The retarded forward diffusion effect was not observed when MgSO(4) and glucose were used as the draw solutes. The reverse flux of both MgSO(4) and glucose was negligible and thus both adsorption and rejection of BPA in the FO mode were identical to those in the RO mode. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  19. Role of Reverse Divalent Cation Diffusion in Forward Osmosis Biofouling.

    Science.gov (United States)

    Xie, Ming; Bar-Zeev, Edo; Hashmi, Sara M; Nghiem, Long D; Elimelech, Menachem

    2015-11-17

    We investigated the role of reverse divalent cation diffusion in forward osmosis (FO) biofouling. FO biofouling by Pseudomonas aeruginosa was simulated using pristine and chlorine-treated thin-film composite polyamide membranes with either MgCl2 or CaCl2 draw solution. We related FO biofouling behavior-water flux decline, biofilm architecture, and biofilm composition-to reverse cation diffusion. Experimental results demonstrated that reverse calcium diffusion led to significantly more severe water flux decline in comparison with reverse magnesium permeation. Unlike magnesium, reverse calcium permeation dramatically altered the biofilm architecture and composition, where extracellular polymeric substances (EPS) formed a thicker, denser, and more stable biofilm. We propose that FO biofouling was enhanced by complexation of calcium ions to bacterial EPS. This hypothesis was confirmed by dynamic and static light scattering measurements using extracted bacterial EPS with the addition of either MgCl2 or CaCl2 solution. We observed a dramatic increase in the hydrodynamic radius of bacterial EPS with the addition of CaCl2, but no change was observed after addition of MgCl2. Static light scattering revealed that the radius of gyration of bacterial EPS with addition of CaCl2 was 20 times larger than that with the addition of MgCl2. These observations were further confirmed by transmission electron microscopy imaging, where bacterial EPS in the presence of calcium ions was globular, while that with magnesium ions was rod-shaped.

  20. Life cycle cost of a hybrid forward osmosis – low pressure reverse osmosis system for seawater desalination and wastewater recovery

    KAUST Repository

    Valladares Linares, Rodrigo

    2015-10-19

    In recent years, forward osmosis (FO) hybrid membrane systems have been investigated as an alternative to conventional high-pressure membrane processes (i.e. reverse osmosis (RO)) for seawater desalination and wastewater treatment and recovery. Nevertheless, their economic advantage in comparison to conventional processes for seawater desalination and municipal wastewater treatment has not been clearly addressed. This work presents a detailed economic analysis on capital and operational expenses (CAPEX and OPEX) for: i) a hybrid forward osmosis – low-pressure reverse osmosis (FO-LPRO) process, ii) a conventional seawater reverse osmosis (SWRO) desalination process, and iii) a membrane bioreactor – reverse osmosis – advanced oxidation process (MBR-RO-AOP) for wastewater treatment and reuse. The most important variables affecting economic feasibility are obtained through a sensitivity analysis of a hybrid FO-LPRO system. The main parameters taken into account for the life cycle costs are the water quality characteristics (similar feed water and similar water produced), production capacity of 100,000 m3 d−1 of potable water, energy consumption, materials, maintenance, operation, RO and FO module costs, and chemicals. Compared to SWRO, the FO-LPRO systems have a 21% higher CAPEX and a 56% lower OPEX due to savings in energy consumption and fouling control. In terms of the total water cost per cubic meter of water produced, the hybrid FO-LPRO desalination system has a 16% cost reduction compared to the benchmark for desalination, mainly SWRO. Compared to the MBR-RO-AOP, the FO-LPRO systems have a 7% lower CAPEX and 9% higher OPEX, resulting in no significant cost reduction per m3 produced by FO-LPRO. Hybrid FO-LPRO membrane systems are shown to have an economic advantage compared to current available technology for desalination, and comparable costs with a wastewater treatment and recovery system. Based on development on FO membrane modules, packing density, and

  1. Poly/vinyl alcohol/ membranes for reverse osmosis

    Science.gov (United States)

    Katz, M. G.; Wydeven, T., Jr.

    1981-01-01

    A description is presented of the results of studies of the water and salt transport properties of PVA membranes, taking into account radiation crosslinked PVA membranes, diffusive salt permeability through PVA membranes, and heat treated PVA membranes. The experimental findings support an occurrence of independent water, and salt permeation processes. It is suggested that the salt permeation is governed by a solution-diffusion transport mechanism. The preparation of thin skinned, asymmetric PVA membranes is also discussed. The employed method has a certain similarity to the classical phase inversion method, which is widely applied in the casting of asymmetric reverse osmosis membranes. Instead of using a gelling bath composed of a nonsolvent for the membrane material and miscible with the solvent from which the membrane is cast, a 'complexing' bath is used, which is a solution of a complexing agent in water.

  2. Algal blooms: an emerging threat to seawater reverse osmosis desalination

    KAUST Repository

    Villacorte, Loreen O.

    2014-08-04

    Seawater reverse osmosis (SWRO) desalination technology has been rapidly growing in terms of installed capacity and global application over the last decade. An emerging threat to SWRO application is the seasonal proliferation of microscopic algae in seawater known as algal blooms. Such blooms have caused operational problems in SWRO plants due to clogging and poor effluent quality of the pre-treatment system which eventually forced the shutdown of various desalination plants to avoid irreversible fouling of downstream SWRO membranes. This article summarizes the current state of SWRO technology and the emerging threat of algal blooms to its application. It also highlights the importance of studying the algal bloom phenomena in the perspective of seawater desalination, so proper mitigation and preventive strategies can be developed in the near future. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  3. Poly/vinyl alcohol/ membranes for reverse osmosis

    Science.gov (United States)

    Katz, M. G.; Wydeven, T., Jr.

    1981-01-01

    A description is presented of the results of studies of the water and salt transport properties of PVA membranes, taking into account radiation crosslinked PVA membranes, diffusive salt permeability through PVA membranes, and heat treated PVA membranes. The experimental findings support an occurrence of independent water, and salt permeation processes. It is suggested that the salt permeation is governed by a solution-diffusion transport mechanism. The preparation of thin skinned, asymmetric PVA membranes is also discussed. The employed method has a certain similarity to the classical phase inversion method, which is widely applied in the casting of asymmetric reverse osmosis membranes. Instead of using a gelling bath composed of a nonsolvent for the membrane material and miscible with the solvent from which the membrane is cast, a 'complexing' bath is used, which is a solution of a complexing agent in water.

  4. Molecular dynamics study of a polymeric reverse osmosis membrane.

    Energy Technology Data Exchange (ETDEWEB)

    Harder, E.; Walters, D. E.; Bodnar, Y. D.; Faibish, R. S.; Roux, B. (Nuclear Engineering Division); (Univ. of Chicago); (Rosalind Franklin Univ. of Medicine and Science)

    2009-07-30

    Molecular dynamics (MD) simulations are used to investigate the properties of an atomic model of an aromatic polyamide reverse osmosis membrane. The monomers forming the polymeric membrane are cross-linked progressively on the basis of a heuristic distance criterion during MD simulations until the system interconnectivity reaches completion. Equilibrium MD simulations of the hydrated membrane are then used to determine the density and diffusivity of water within the membrane. Given a 3 MPa pressure differential and a 0.125 {micro}m width membrane, the simulated water flux is calculated to be 1.4 x 10{sup -6} m/s, which is in fair agreement with an experimental flux measurement of 7.7 x 10{sup -6} m/s.

  5. Separation performance and interfacial properties of nanocomposite reverse osmosis membranes

    KAUST Repository

    Pendergast, MaryTheresa M.

    2013-01-01

    Four different types of nanocomposite reverse osmosis (RO) membranes were formed by interfacial polymerization of either polyamide (PA) or zeolite A-polyamide nanocomposite (ZA-PA) thin films over either pure polysulfone (PSf) or zeolite A-polysulfone nanocomposite (ZA-PSf) support membranes cast by wet phase inversion. All three nanocomposite membranes exhibited superior separation performance and interfacial properties relative to hand-cast TFC analogs including: (1) smoother, more hydrophilic surfaces (2) higher water permeability and salt rejection, and (3) improved resistance to physical compaction. Less compaction occurred for membranes with nanoparticles embedded in interfacially polymerized coating films, which adds further proof that flux decline associated with physical compaction is influenced by coating film properties in addition to support membrane properties. The new classes of nanocomposite membrane materials continue to offer promise of further improved RO membranes for use in desalination and advanced water purification. © 2011 Elsevier B.V.

  6. Validation of 3D simulations of reverse osmosis membrane biofouling.

    Science.gov (United States)

    Pintelon, Thomas R R; Creber, Sarah A; von der Schulenburg, Daniel A Graf; Johns, Michael L

    2010-07-01

    The increasing demand for drinking water and its stricter quality requirements have resulted in an exponentially expanding industry of membrane filtration processes. Currently, reverse osmosis (RO) is the most common method of desalination, able to produce water that is virtually free of pollutants and pathogenic micro-organisms. Biofouling of these devices however is a significant limitation. Here we present a 3D simulation of RO membrane biofouling based on a lattice Boltzmann (LB) platform that we subsequently favorably compare with experimental data. This data consists of temporally (and spatially) resolved velocity measurements acquired for a RO membrane using magnetic resonance techniques. The effect of biofilm cohesive strength on system pressure drop is then explored; weaker biomass is observed to have a reduced impact on pressure drop (per unit biomass accumulated).

  7. Chemical treatment of commercial reverse osmosis membranes for use in FO

    Science.gov (United States)

    Commercially available reverse osmosis (RO) membranes – SW30HR, BW30, and AG – were chemically treated for use in forward osmosis (FO). Nitric acid, phosphoric acid, sulfuric acid, ethanol, and ethanol–acid–water ternary solutions were employed for the treatment. All three membra...

  8. Chemical treatment of commercial reverse osmosis membranes for use in FO

    Science.gov (United States)

    Commercially available reverse osmosis (RO) membranes – SW30HR, BW30, and AG – were chemically treated for use in forward osmosis (FO). Nitric acid, phosphoric acid, sulfuric acid, ethanol, and ethanol–acid–water ternary solutions were employed for the treatment. All three membra...

  9. Solar Desalination System Model for Sizing of Photovoltaic Reverse Osmosis (PVRO)

    KAUST Repository

    Habib, Abdulelah

    2015-06-28

    The focus of this paper is to optimize the solar energy utilization in the water desalination process. Due to variable nature of solar energy, new system design is needed to address this challenge. Here, reverse osmosis units, as the electrical loads, are considered as an ON/OFF units to track these solar energy variations. Reverse osmosis units are different in sizes and numbers. Various combinations of reverse osmosis units in size and capacity provide different water desalination system performances. To assess each scenario of reverse osmosis units, the total capital cost and operation and maintenance (O&M) cost are considered. The implemented optimization algorithm search all of the possible scenarios to find the best solution. This paper deploys the solar irradiance data which is provided from west coast (Red Sea) of Saudi Arabia for model construction and optimization algorithm implementation.

  10. REMOVAL OF CHLORINATED AND BROMINATED ALKANES FROM DRINKING WATER USING REVERSE OSMOSIS

    Science.gov (United States)

    Membrane use in water treatment has historically focused on desalination. With the development of new membrane materials, attention began to focus on reverse osmosis and pervaporation as alternatives to traditional water treatment processes. This paper addresses the use of reve...

  11. REMOVAL OF CHLORINATED AND BROMINATED ALKANES FROM DRINKING WATER USING REVERSE OSMOSIS

    Science.gov (United States)

    Membrane use in water treatment has historically focused on desalination. With the development of new membrane materials, attention began to focus on reverse osmosis and pervaporation as alternatives to traditional water treatment processes. This paper addresses the use of reve...

  12. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    T.M. Whitworth; Liangxiong Li

    2002-09-15

    This report describes work performed during the second year of the project ''Modified reverse osmosis system for treatment of produced waters.'' We performed two series of reverse osmosis experiments using very thin bentonite clay membranes compacted to differing degrees. The first series of 10 experiments used NaCl solutions with membranes that ranged between 0.041 and 0.064mm in thickness. Our results showed compaction of such ultra-thin clay membranes to be problematic. The thickness of the membranes was exceeded by the dimensional variation in the machined experimental cell and this is believed to have resulted in local bypassing of the membrane with a resultant decrease in solute rejection efficiency. In two of the experiments, permeate flow was varied as a percentage of the total flow to investigate results of changing permeate flow on solute rejection. In one experiment, the permeate flow was varied between 2.4 and 10.3% of the total flow with no change in solute rejection. In another experiment, the permeate flow was varied between 24.6 and 52.5% of the total flow. In this experiment, the solute rejection rate decreased as the permeate occupied greater fractions of the total flow. This suggests a maximum solute rejection efficiency for these clay membranes for a permeate flow of between 10.3 and 24.6% of the total; flow. Solute rejection was found to decrease with increasing salt concentration and ranged between 62.9% and 19.7% for chloride and between 61.5 and 16.8% for sodium. Due to problems with the compaction procedure and potential membrane bypassing, these rejection rates are probably not the upper limit for NaCl rejection by bentonite membranes. The second series of four reverse osmosis experiments was conducted with a 0.057mm-thick bentonite membrane and dilutions of a produced water sample with an original TDS of 196,250 mg/l obtained from a facility near Loco Hill, New Mexico, operated by an independent. These experiments

  13. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    T.M. Whitworth; Liangxiong Li

    2002-09-15

    This report describes work performed during the first year of the project ''Modified Reverse Osmosis System for Treatment of Produced Waters.'' This research project has two objectives. The first objective is to test the use of clay membranes in the treatment of produced waters by reverse osmosis. The second objective is to test the ability of a system patented by the New Mexico Tech Research Foundation to remove salts from reverse osmosis waste streams as a solid. We performed 12 experiments using clay membranes in cross-flow experimental cells. We found that, due to dispersion in the porous frit used adjacent to the membrane, the concentration polarization layer seems to be completely (or nearly completely) destroyed at low flow rates. This observation suggests that clay membranes used with porous frit material many reach optimum rejection rates at lower pumping rates than required for use with synthetic membranes. The solute rejection efficiency decreases with increasing solution concentration. For the membranes and experiments reported here, the rejection efficiency ranged from 71% with 0.01 M NaCl solution down to 12% with 2.3 M NaCl solution. More compacted clay membranes will have higher rejection capabilities. The clay membranes used in our experiments were relatively thick (approximately 0.5 mm). The active layer of most synthetic membranes is only 0.04 {micro}m (0.00004 mm), approximately 1250 times thinner than the clay membranes used in these experiments. Yet clay membranes as thin as 12 {micro}m have been constructed (Fritz and Eady, 1985). Since Darcy's law states that the flow through a material of constant permeability is inversely proportional to it's the material's thickness, then, based on these experimental observations, a very thin clay membrane would be expected to have much higher flow rates than the ones used in these experiments. Future experiments will focus on testing very thin clay membranes. The

  14. Study of different pretreatments for reverse osmosis reclamation of a petrochemical secondary effluent.

    Science.gov (United States)

    Benito-Alcázar, C; Vincent-Vela, M C; Gozálvez-Zafrilla, J M; Lora-García, J

    2010-06-15

    Conventionally treated petrochemical wastewaters contain substantial quantities of hazardous pollutants. In addition, wastewater reuse is being enhanced as a consequence of the shortage of fresh water. Advanced petrochemical wastewater treatment for water reuse will reduce hazardous pollutants discharges as well as water consumption. Reverse osmosis is a suitable technology to obtain pure water. This work studies the adequacy of different pretreatments applied to a petrochemical secondary effluent to produce a suitable feeding for reverse osmosis treatment. The permeate obtained can be used in the petrochemical industry for different processes. In this work, several experiments (granulated activated carbon filtration, ultrafiltration, nanofiltration and granulated activated carbon filtration coupled with nanofiltration) were performed to improve the conventional pretreatment. Total organic carbon, chemical oxygen demand, turbidity and silt density index were used to evaluate water quality for reverse osmosis feeding. In granulated activated carbon filtration, all the measured parameters but silt density index indicated a good filtrate quality to feed reverse osmosis membranes. Although the ultrafiltration permeate obtained was suitable for reverse osmosis, nanofiltration and granulated activated carbon filtration coupled with NF provided a better effluent quality for reverse osmosis than the other pretreatments studied. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Biofouling and microbial communities in membrane distillation and reverse osmosis.

    Science.gov (United States)

    Zodrow, Katherine R; Bar-Zeev, Edo; Giannetto, Michael J; Elimelech, Menachem

    2014-11-18

    Membrane distillation (MD) is an emerging desalination technology that uses low-grade heat to drive water vapor across a microporous hydrophobic membrane. Currently, little is known about the biofilms that grow on MD membranes. In this study, we use estuarine water collected from Long Island Sound in a bench-scale direct contact MD system to investigate the initial stages of biofilm formation. For comparison, we studied biofilm formation in a bench-scale reverse osmosis (RO) system using the same feedwater. These two membrane desalination systems expose the natural microbial community to vastly different environmental conditions: high temperatures with no hydraulic pressure in MD and low temperature with hydraulic pressure in RO. Over the course of 4 days, we observed a steady decline in bacteria concentration (nearly 2 orders of magnitude) in the MD feed reservoir. Even with this drop in planktonic bacteria, significant biofilm formation was observed. Biofilm morphologies on MD and RO membranes were markedly different. MD membrane biofilms were heterogeneous and contained several colonies, while RO membrane biofilms, although thicker, were a homogeneous mat. Phylogenetic analysis using next-generation sequencing of 16S rDNA showed significant shifts in the microbial communities. Bacteria representing the orders Burkholderiales, Rhodobacterales, and Flavobacteriales were most abundant in the MD biofilms. On the basis of the results, we propose two different regimes for microbial community shifts and biofilm development in RO and MD systems.

  16. Seawater reverse osmosis desalination and (harmful) algal blooms

    KAUST Repository

    Villacorte, Loreen O.

    2015-03-01

    This article reviews the occurrence of HABs in seawater, their effects on the operation of seawater reverse osmosis (SWRO) plants, the indicators for quantifying/predicting these effects, and the pretreatment strategies for mitigating operational issues during algal blooms. The potential issues in SWRO plants during HABs are particulate/organic fouling of pretreatment systems and biological fouling of RO membranes, mainly due to accumulation of algal organic matter (AOM). The presence of HAB toxins in desalinated water is also a potential concern but only at very low concentrations. Monitoring algal cell density, AOM concentrations and membrane fouling indices is a promising approach to assess the quality of SWRO feedwater and performance of the pretreatment system. When geological condition is favourable, subsurface intake can be a robust pretreatment for SWRO during HABs. Existing SWRO plants with open intake and are fitted with granular media filtration can improve performance in terms of capacity and product water quality, if preceded by dissolved air flotation or sedimentation. However, the application of advanced pretreatment using ultrafiltration membrane with in-line coagulation is often a better option as it is capable of maintaining stable operation and better RO feed water quality during algal bloom periods with significantly lower chemical consumption.

  17. Does chlorination of seawater reverse osmosis membranes control biofouling?

    Science.gov (United States)

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

    2015-07-01

    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.

  18. Kinetic study of seawater reverse osmosis membrane fouling

    KAUST Repository

    Khan, Muhammad

    2013-10-01

    Reverse osmosis (RO) membrane fouling is not a static state but a dynamic phenomenon. The investigation of fouling kinetics and dynamics of change in the composition of the foulant mass is essential to elucidate the mechanism of fouling and foulant-foulant interactions. The aim of this work was to study at a lab scale the fouling process with an emphasis on the changes in the relative composition of foulant material as a function of operating time. Fouled membrane samples were collected at 8 h, and 1, 2, and 4 weeks on a lab-scale RO unit operated in recirculation mode. Foulant characterization was performed by CLSM, AFM, ATR-FTIR, pyrolysis GC-MS, and ICP-MS techniques. Moreover, measurement of active biomass and analysis of microbial diversity were performed by ATP analysis and DNA extraction, followed by pyro-sequencing, respectively. A progressive increase in the abundance of almost all the foulant species was observed, but their relative proportion changed over the age of the fouling layer. Microbial population in all the membrane samples was dominated by specific groups/species belonging to Proteobacteria and Actinobacteria phyla; however, similar to abiotic foulant, their relative abundance also changed with the biofilm age. © 2013 American Chemical Society.

  19. Permeability of uncharged organic molecules in reverse osmosis desalination membranes.

    Science.gov (United States)

    Dražević, Emil; Košutić, Krešimir; Svalina, Marin; Catalano, Jacopo

    2017-06-01

    Reverse osmosis (RO) membranes are primarily designed for removal of salts i.e. for desalination of brackish and seawater, but they have also found applications in removal of organic molecules. While it is clear that steric exclusion is the dominant removal mechanism, the fundamental explanation for how and why the separation occurs remains elusive. Until recently there was no strong microscopic evidences elucidating the structure of the active polyamide layers of RO membranes, and thus they have been conceived as "black boxes"; or as an array of straight capillaries with a distribution of radii; or as polymers with a small amount of polymer free domains. The knowledge of diffusion and sorption coefficients is a prerequisite for understanding the intrinsic permeability of any organic solute in any polymer. At the same time, it is technically challenging to accurately measure these two fundamental parameters in very thin (20-300 nm) water-swollen active layers. In this work we have measured partition and diffusion coefficients and RO permeabilities of ten organic solutes in water-swollen active layers of two types of RO membranes, low (SWC4+) and high flux (XLE). We deduced from our results and recent microscopic studies that the solute flux of organic molecules in polyamide layer of RO membranes occurs in two domains, dense polymer (the key barrier layer) and the water filled domains. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Reverse osmosis brine for phosphorus recovery from source separated urine.

    Science.gov (United States)

    Tian, Xiujun; Wang, Guotian; Guan, Detian; Li, Jiuyi; Wang, Aimin; Li, Jin; Yu, Zhe; Chen, Yong; Zhang, Zhongguo

    2016-12-01

    Phosphorus (P) recovery from waste streams has recently been recognized as a key step in the sustainable supply of this indispensable and non-renewable resource. The feasibility of using brine from a reverse osmosis (RO) membrane unit treating cooling water as a precipitant for P recovery from source separated urine was evaluated in the present study. P removal efficiency, process parameters and precipitate properties were investigated in batch and continuous flow experiments. More than 90% of P removal was obtained from both undiluted fresh and hydrolyzed urines by mixing with RO brine (1:1, v/v) at a pH over 9.0. Around 2.58 and 1.24 Kg of precipitates could be recovered from 1 m(3) hydrolyzed and fresh urine, respectively, and the precipitated solids contain 8.1-19.0% of P, 10.3-15.2% of Ca, 3.7-5.0% of Mg and 0.1-3.5% of ammonium nitrogen. Satisfactory P removal performance was also achieved in a continuous flow precipitation reactor with a hydraulic retention time of 3-6 h. RO brine could be considered as urinal and toilet flush water despite of a marginally higher precipitation tendency than tap water. This study provides a widely available, low - cost and efficient precipitant for P recovery in urban areas, which will make P recovery from urine more economically attractive. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Reverse osmosis for wash water recovery in space vehicles.

    Science.gov (United States)

    Lawrence, R. W.; Saltonstall, C. W., Jr.

    1973-01-01

    Tests were carried out on both synthetic and real wash water derived from clothes laundry to determine the utility of reverse osmosis in recovering the water for recycle use. A blend membrane made from cellulose di- and triacetates, and a cross-linked cellulose acetate/methacrylate were evaluated. Both were found acceptable. A number of detergents were evaluated, including a cationic detergent, sodium dodecyl sulfate, potassium palmitate, and sodium dodecylbenzenesulfonate. The tests were all made at a temperature of 165 F to minimize microbial growth. Long-term (15 to 30 day) runs were made at 600 and 400 psi on laundry water which was pretreated either by alum addition and sand filtration or by filtration only through 0.5 micron filters. A 30-day run was made using a 2-in. diameter by 22-in. long spiral module at 400 psig with filtering as the pretreatment. The membrane fouling by colloidal matter was found to be controllable. The unit produced initially 55 gal/day and 27 gal/day after 30 days.

  2. Molecular level water and solute transport in reverse osmosis membranes

    Science.gov (United States)

    Lueptow, Richard M.; Shen, Meng; Keten, Sinan

    2015-11-01

    The water permeability and rejection characteristics of six solutes, methanol, ethanol, 2-propanol, urea, Na+, and Cl-, were studied for a polymeric reverse osmosis (RO) membrane using non-equilibrium molecular dynamics simulations. Results indicate that water flux increases with an increasing fraction of percolated free volume in the membrane polymer structure. Solute molecules display Brownian motion and hop from pore to pore as they pass through the membrane. The solute rejection depends on both the size of the solute molecule and the chemical interaction of the solute with water and the membrane. When the open spaces in the polymeric structure are such that solutes have to shed at least one water molecule from their solvation shell to pass through the membrane molecular structure, the water-solute pair interaction energy governs solute rejection. Organic solutes more easily shed water molecules than ions to more readily pass through the membrane. Hydrogen-bonding sites for molecules like urea also lead to a higher rejection. These findings underline the importance of the solute's solvation shell and solute-water-membrane chemistry in solute transport and rejection in RO membranes. Funded by the Institute for Sustainability and Energy at Northwestern with computing resources from XSEDE (NSF grant ACI-1053575).

  3. Thinning of reverse osmosis membranes by ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Hong, E-mail: menghong@mail.buct.edu.cn; Gong, Beibei; Geng, Tao; Li, Chunxi

    2014-02-15

    In this study, ionic liquids (ILs) were used to thin out the dense layer and, in turn, tune the surface properties and separation performance of commercial aromatic polyamide reverse osmosis membranes. It was observed that the structure of the ILs and dipping time had a strong impact on the dense layer thickness and morphology. This can be understood in terms of the dissolubility and interaction force between ILs and the organic membrane surface, such as hydrogen bonding and π–π interactions. Among the ILs synthesized, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) showed the most promising thinning effects. It was observed that the thickness of the dense layer on the surface decreased from 127 to 67 nm after dipping treatment with [BMIM]Cl for 24 h. The water flux was enhanced by 20% at the expense of a slight decline of salt rejection. AFM, contact angle and zeta potential analyses suggest that the surface hydrophilicity and electronegativity increased, while the roughness decreased, which improved the anti-fouling properties.

  4. Thinning of reverse osmosis membranes by ionic liquids

    Science.gov (United States)

    Meng, Hong; Gong, Beibei; Geng, Tao; Li, Chunxi

    2014-02-01

    In this study, ionic liquids (ILs) were used to thin out the dense layer and, in turn, tune the surface properties and separation performance of commercial aromatic polyamide reverse osmosis membranes. It was observed that the structure of the ILs and dipping time had a strong impact on the dense layer thickness and morphology. This can be understood in terms of the dissolubility and interaction force between ILs and the organic membrane surface, such as hydrogen bonding and π-π interactions. Among the ILs synthesized, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) showed the most promising thinning effects. It was observed that the thickness of the dense layer on the surface decreased from 127 to 67 nm after dipping treatment with [BMIM]Cl for 24 h. The water flux was enhanced by 20% at the expense of a slight decline of salt rejection. AFM, contact angle and zeta potential analyses suggest that the surface hydrophilicity and electronegativity increased, while the roughness decreased, which improved the anti-fouling properties.

  5. Experimentation with a reverse osmosis plant powered by renewable energies

    Energy Technology Data Exchange (ETDEWEB)

    Segura, L.; Gomez, A. [Las Palmas de Gran Canaria Univ., Las Palmas (Spain). Dept. of Process Engineering; Nuez, I. [Las Palmas de Gran Canaria Univ., Las Palmas (Spain). Dept. of Electronic and Automatic Engineering

    2006-07-01

    This paper described a set of tests conducted in a reverse osmosis plant powered by renewable energy sources. Variations on feed flow, reject flow, recovery and power consumption were investigated. The plant has a production of over 115 m{sup 3} per day. During the experiments, the plant was required to operate at variable loading conditions. An energy recovery system was then developed to operate effectively with the observed variable load conditions. The system was incorporated within the reject flow system and was comprised of a Pelton turbine matched to the axis of an asynchronous energy generator. The system was designed to avoid making changes to the actual hydraulic circuit of the plant. Recovery system failures did not necessitate plant stoppages during the testing period. Simulations conducted to assess the energy system showed that optimal performance of the plant was between 16 and 18 kW with a working pressure of between 57 to 67 bars. Results also suggested that installing the system in the evacuation brine line would maximize the use of kinetic energy. It was concluded that energy recovery systems are ideal for use in seawater installations where functioning pressure levels are high. 14 refs., 1 tab., 5 figs.

  6. Rejection mechanisms for contaminants in polymeric reverse osmosis membranes

    CERN Document Server

    Shen, Meng; Lueptow, Richard M

    2016-01-01

    Despite the success of reverse osmosis (RO) for water purification, the molecular-level physico-chemical processes of contaminant rejection are not well understood. Here we carry out NEMD simulations on a model polyamide RO membrane to understand the mechanisms of transport and rejection of both ionic and neutral contaminants in water. We observe that the rejection changes non-monotonously with ion sizes. In particular, the rejection of urea, 2.4 A radius, is higher than ethanol, 2.6 A radius, and the rejections for organic solutes, 2.2-2.8 A radius, are lower than Na+, 1.4 A radius, or Cl-, 2.3 A radius. We show that this can be explained in terms of the solute accessible intermolecular volume in the membrane and the solute-water pair interaction energy. If the smallest open spaces in the membrane's molecular structure are all larger than the hydrated solute, then the solute-water pair interaction energy does not matter. However, when the open spaces in the polymeric structure are such that solutes have to s...

  7. 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.

  8. Life cycle cost of a hybrid forward osmosis - low pressure reverse osmosis system for seawater desalination and wastewater recovery.

    Science.gov (United States)

    Valladares Linares, R; Li, Z; Yangali-Quintanilla, V; Ghaffour, N; Amy, G; Leiknes, T; Vrouwenvelder, J S

    2016-01-01

    In recent years, forward osmosis (FO) hybrid membrane systems have been investigated as an alternative to conventional high-pressure membrane processes (i.e. reverse osmosis (RO)) for seawater desalination and wastewater treatment and recovery. Nevertheless, their economic advantage in comparison to conventional processes for seawater desalination and municipal wastewater treatment has not been clearly addressed. This work presents a detailed economic analysis on capital and operational expenses (CAPEX and OPEX) for: i) a hybrid forward osmosis - low-pressure reverse osmosis (FO-LPRO) process, ii) a conventional seawater reverse osmosis (SWRO) desalination process, and iii) a membrane bioreactor - reverse osmosis - advanced oxidation process (MBR-RO-AOP) for wastewater treatment and reuse. The most important variables affecting economic feasibility are obtained through a sensitivity analysis of a hybrid FO-LPRO system. The main parameters taken into account for the life cycle costs are the water quality characteristics (similar feed water and similar water produced), production capacity of 100,000 m(3) d(-1) of potable water, energy consumption, materials, maintenance, operation, RO and FO module costs, and chemicals. Compared to SWRO, the FO-LPRO systems have a 21% higher CAPEX and a 56% lower OPEX due to savings in energy consumption and fouling control. In terms of the total water cost per cubic meter of water produced, the hybrid FO-LPRO desalination system has a 16% cost reduction compared to the benchmark for desalination, mainly SWRO. Compared to the MBR-RO-AOP, the FO-LPRO systems have a 7% lower CAPEX and 9% higher OPEX, resulting in no significant cost reduction per m(3) produced by FO-LPRO. Hybrid FO-LPRO membrane systems are shown to have an economic advantage compared to current available technology for desalination, and comparable costs with a wastewater treatment and recovery system. Based on development on FO membrane modules, packing density, and

  9. Obtaining water with a high degree of purity by using reverse osmosis

    Directory of Open Access Journals (Sweden)

    Nicolae Chirilă

    2011-12-01

    Full Text Available In this paper, we used the method of reverse osmosis in order to obtain water with a high degree of purity. For this aim, we used the TKA 20-120ECO device. We completed physic-chemical determinations for the water of supply, as well as for the water obtained after the osmosis process. The results that we obtained are relevant and interesting.

  10. Forward osmosis for the treatment of reverse osmosis concentrate from water reclamation: process performance and fouling control.

    Science.gov (United States)

    Kazner, C; Jamil, S; Phuntsho, S; Shon, H K; Wintgens, T; Vigneswaran, S

    2014-01-01

    While high quality water reuse based on dual membrane filtration (membrane filtration or ultrafiltration, followed by reverse osmosis) is expected to be progressively applied, treatment and sustainable management of the produced reverse osmosis concentrate (ROC) are still important issues. Forward osmosis (FO) is a promising technology for maximising water recovery and further dewatering ROC so that zero liquid discharge is produced. Elevated concentrations of organic and inorganic compounds may act as potential foulants of the concentrate desalting system, in that they consist of, for example, FO and a subsequent crystallizer. The present study investigated conditions under which the FO system can serve as concentration phase with the focus on its fouling propensity using model foulants and real ROC. Bulk organics from ROC consisted mainly of humic acids (HA) and building blocks since wastewater-derived biopolymers were retained by membrane filtration or ultrafiltration. Organic fouling of the FO system by ROC-derived bulk organics was low. HA was only adsorbed moderately at about 7% of the initial concentration, causing a minor flux decline of about 2-4%. However, scaling was a major impediment to this process if not properly controlled, for instance by pH adjustment or softening.

  11. Response of foraminifera to a reverse osmosis briny discharge

    Science.gov (United States)

    Small, Richard Eustace Aiken

    Reverse osmosis water treatment plants are becoming the preferred means of generating potable water for many eastern North Carolina communities. At these facilities, reject brine solutions---sometimes containing up to 10 times the initial concentration of dissolved solids---are created and often discharged into estuarine waters. Several state and federal agencies have expressed concern over the potential ecological impacts this wastewater could have on these sensitive environments. Monitoring of a brine discharge site in Currituck County, North Carolina revealed significantly higher conductivity values within ~50 m of the point source. One group of organisms that have proven useful in other studies for monitoring impact of anthropogenic pollution in estuaries is Foraminifera. Foraminifera are abundant microorganisms that are widespread in most marginal-marine and marine environments; nevertheless, individual taxa are highly selective of their habitat. Nearly all species build shells (tests) that are preserved in coastal sediments, allowing for reconstruction of previous marine conditions. Species abundance data was collected from surface and sub-surface samples taken in the area surrounding the brine point source. Two taxa (Ammobaculites spp. and Ammotium sp.) accounted for 98.5% of all normalized specimens. Abundance is significantly less in the sub-surface samples (Student's t-test, p<0.0001), likely due to taphonomic effects. Abundance does not appear correlated with discharge of the wastewater; instead, natural parameters appear to affect abundance in an assemblage to a greater degree. Species distribution is similar in surface and sub-surface samples. Foraminiferal diversity is significantly less near the discharge based on one sample collected within 5 m of the discharge site; samples at greater distances do not appear affected. Loss of diversity within a few meters of the discharge site is consistent with previous studies, but more data would be needed to

  12. A novel hybrid process of reverse electrodialysis and reverse osmosis for low energy seawater desalination and brine management

    NARCIS (Netherlands)

    Li, W.; Krantz, W.B.; Cornelissen, E.R.; Post, J.W.; Verliefde, A.R.D.; Tang, C.Y.

    2013-01-01

    This paper introduces a novel concept for a hybrid desalination system that combines reverse electrodialysis (RED) and reverse osmosis (RO) processes. In this hybrid process the RED unit harvests the energy in the form of electricity from the salinity gradient between a highly concentrated solution

  13. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    Robert L. Lee; Junghan Dong

    2004-06-03

    This final report of ''Modified Reverse Osmosis System for Treatment of Produced Water,'' DOE project No. DE-FC26-00BC15326 describes work performed in the third year of the project. Several good results were obtained, which are documented in this report. The compacted bentonite membranes were replaced by supported bentonite membranes, which exhibited the same salt rejection capability. Unfortunately, it also inherited the clay expansion problem due to water invasion into the interlayer spaces of the compacted bentonite membranes. We noted that the supported bentonite membrane developed in the project was the first of its kind reported in the literature. An {alpha}-alumina-supported MFI-type zeolite membrane synthesized by in-situ crystallization was fabricated and tested. Unlike the bentonite clay membranes, the zeolite membranes maintained stability and high salt rejection rate even for a highly saline solution. Actual produced brines from gas and oil fields were then tested. For gas fields producing brine, the 18,300 ppm TDS (total dissolved solids) in the produced brine was reduced to 3060 ppm, an 83.3% rejection rate of 15,240 ppm salt rejection. For oilfield brine, while the TDS was reduced from 181,600 ppm to 148,900 ppm, an 18% rejection rate of 32,700 ppm reduction, the zeolite membrane was stable. Preliminary results show the dissolved organics, mainly hydrocarbons, did not affect the salt rejection. However, the rejection of organics was inconclusive at this point. Finally, the by-product of this project, the {alpha}-alumina-supported Pt-Co/Na Y catalytic zeolite membrane was developed and demonstrated for overcoming the two-step limitation of nonoxidation methane (CH{sub 4}) conversion to higher hydrocarbons (C{sub 2+}) and hydrogen (H{sub 2}). Detailed experiments to obtain quantitative results of H{sub 2} generation for various conditions are now being conducted. Technology transfer efforts included five manuscripts submitted to

  14. Environmental concerns of desalinating seawater using reverse osmosis.

    Science.gov (United States)

    Tularam, Gurudeo Anand; Ilahee, Mahbub

    2007-08-01

    This Critical Review on environmental concerns of desalination plants suggests that planning and monitoring stages are critical aspects of successful management and operation of plants. The site for the desalination plants should be selected carefully and should be away from residential areas particularly for forward planning for possible future expansions. The concerning issues identified are noise pollution, visual pollution, reduction in recreational fishing and swimming areas, emission of materials into the atmosphere, the brine discharge and types of disposal methods used are the main cause of pollution. The reverse osmosis (RO) method is the preferred option in modern times especially when fossil fuels are becoming expensive. The RO has other positives such as better efficiency (30-50%) when compared with distillation type plants (10-30%). However, the RO membranes are susceptible to fouling and scaling and as such they need to be cleaned with chemicals regularly that may be toxic to receiving waters. The input and output water in desalination plants have to be pre and post treated, respectively. This involves treating for pH, coagulants, Cl, Cu, organics, CO(2), H(2)S and hypoxia. The by-product of the plant is mainly brine with concentration at times twice that of seawater. This discharge also includes traces of various chemicals used in cleaning including any anticorrosion products used in the plant and has to be treated to acceptable levels of each chemical before discharge but acceptable levels vary depending on receiving waters and state regulations. The discharge of the brine is usually done by a long pipe far into the sea or at the coastline. Either way the high density of the discharge reaches the bottom layers of receiving waters and may affect marine life particularly at the bottom layers or boundaries. The longer term effects of such discharge concentrate has not been documented but it is possible that small traces of toxic substances used in the

  15. RO-75: a FORTRAN code for calculation and design optimization of reverse osmosis seawater desalination plants

    Energy Technology Data Exchange (ETDEWEB)

    Glueckstern, P.; Reed, S.A.; Wilson, J.V.

    1976-11-01

    The reverse osmosis process has been used extensively for the conversion of brackish waters to potable water. The process is now nearing commercialization as a means for the conversion of seawater. The computer program (RO-75) is a Fortran code for the optimizatin of the design and economics of seawater reverse osmosis plants. The examples described are based on currently available, commercial membrane modules and prevailing prices. However, the code is very flexible and can be used to optimize plants utilizing future technological improvements and different economic parameters.

  16. Concentration of pineapple juice by reverse osmosis: physicochemical characteristics and consumer acceptance

    OpenAIRE

    Daniel Simões Couto; Lourdes Maria Corrêa Cabral; Virgínia Martins da Matta; Rosires Deliza; Daniela De Grandi Castro Freitas

    2011-01-01

    Reverse osmosis has been used for the concentration of fruit juices with promising considering the quality of the obtained products. The objective of this study was to concentrate single strength pineapple juice by reverse osmosis. The concentration was carried out with polyamide composite membranes in a 0.65 m² plate and frame module at 60 bar transmembrane pressure at 20 °C. The permeate flux was 17 L.hm-2. The total soluble solid content of the juice increased from 11 to 31 °Brix correspon...

  17. Particulate and organic matter fouling of seawater reverse osmosis systems: Characterization, modelling and applications

    NARCIS (Netherlands)

    Salinas Rodriguez, S.G.

    2011-01-01

    Particulate/colloidal and organic fouling in seawater reverse osmosis (SWRO) systems results in flux decline, higher energy costs, increased salt passage, increased cleaning frequency, and use of chemicals. In practice, indices like SDI and MFI are used to assess particulate fouling, but they are pe

  18. The transport of Hydronium and Hydroxide Ions through Reverse Osmosis Membranes

    NARCIS (Netherlands)

    Kezia, K.; Lee, J.; Ogieglo, Wojciech; Hill, A.; Benes, Nieck Edwin; Kentish, S.E.

    2014-01-01

    It is important to understand the fundamental behaviour of reverse osmosis membranes under a range of pH and salinity conditions. In this work, experiments and modelling are used in a complementary manner to better understand these fundamentals. We find experimentally that both pH and salinity can

  19. Investigation of microbial adaptation to salinity variation for treatment of reverse osmosis concentrate by membrane bioreactor

    DEFF Research Database (Denmark)

    Jang, Duksoo; Moon, Chungman; Ahn, Kyuhong

    2014-01-01

    Even though reverse osmosis (RO) technologies are widely used for sustainable water reclamation, the control of concentrates containing a high concentration of dissolved matters originated from feed water should be considered. The effect of variations in salinity on biological wastewater treatmen...

  20. 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),

  1. A Mechanistic Study of Arsenic (III) Rejection by Reverse Osmosis and Nanofiltration Membranes

    Science.gov (United States)

    Suzuki, Tasuma

    2009-01-01

    Reverse osmosis/nanofiltration (RO/NF) membranes are capable to provide an effective barrier for a wide range of contaminants (including disinfection by-products precursors) in a single treatment step. However, solute rejection mechanisms by RO/NF membranes are not well understood. The lack of mechanistic information arises from experimental…

  2. Salinity-gradient power : Evaluation of pressure-retarded osmosis and reverse electrodialysis

    NARCIS (Netherlands)

    Post, Jan W.; Veerman, Joost; Hamelers, Hubertus V.M.; Euverink, Gerrit J.W.; Metz, Sybrand J.; Nymeijer, Kitty; Buisman, Cees J.N.

    2007-01-01

    A huge potential to obtain clean energy exists from mixing water streams with different salt concentrations. Two membrane-based energy conversion techniques are evaluated: pressure-retarded osmosis and reverse electrodialysis. From the literature, a comparison is not possible since the reported perf

  3. Gray water recycle: Effect of pretreatment technologies on low pressure reverse osmosis treatment

    Science.gov (United States)

    Gray water can be a valuable source of water when properly treated to reduce the risks associated with chemical and microbial contamination to acceptable levels for the intended reuse application. In this study, the treatment of gray water using low pressure reverse osmosis (RO) filtration after pre...

  4. A Mechanistic Study of Arsenic (III) Rejection by Reverse Osmosis and Nanofiltration Membranes

    Science.gov (United States)

    Suzuki, Tasuma

    2009-01-01

    Reverse osmosis/nanofiltration (RO/NF) membranes are capable to provide an effective barrier for a wide range of contaminants (including disinfection by-products precursors) in a single treatment step. However, solute rejection mechanisms by RO/NF membranes are not well understood. The lack of mechanistic information arises from experimental…

  5. A survey of structure characterization methods for ultrafiltration and reverse osmosis membranes

    NARCIS (Netherlands)

    Smolders, C.A.; Mulder, M.H.V.; Velden, van der P.M.

    1976-01-01

    Asymmetric membranes consist of a thin skin, which is permselective to certain molecules in solution, and a porous support, serving as a mechanical support layer and also as a transport layer for the permeate. Both in ultrafiltration and in hyperfiltration (reverse osmosis) asymmetric membranes are

  6. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation

    NARCIS (Netherlands)

    Vingerhoeds, M.H.; Nijenhuis, M.A.; Ruepert, N.; Bredie, W.L.P.; Kremer, S.

    2016-01-01

    Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from pe

  7. Adsorption of Phosphonate Antiscalant from Reverse Osmosis Membrane Concentrate onto Granular Ferric Hydroxide

    NARCIS (Netherlands)

    Boels, L.; Keesman, K.J.; Witkamp, G.J.

    2012-01-01

    Adsorptive removal of antiscalants offers a promising way to improve current reverse osmosis (RO) concentrate treatment processes and enables the reuse of the antiscalant in the RO desalination process. This work investigates the adsorption and desorption of the phosphonate antiscalant nitrilotris(m

  8. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation

    NARCIS (Netherlands)

    Vingerhoeds, M.H.; Nijenhuis, M.A.; Ruepert, N.; Bredie, W.L.P.; Kremer, S.

    2016-01-01

    Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from

  9. Fluidized beds as turbulence promoters in the concentration of food liquids by reverse osmosis

    NARCIS (Netherlands)

    Boer, de R.; Zomerman, J.J.; Hiddink, J.; Aufderheyde, J.; Swaay, van W.P.M.; Smolders, C.A.

    1980-01-01

    Fluidized beds offer a potential improvement of reverse osmosis processes for food liquids, less fouling of the membrane, and reduced energy consumption. Our experiments were concerned with tubular systems in which fluidized beds of glass, steel, and lead beads were used. Glass beads appeared to be

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

    NARCIS (Netherlands)

    Vrouwenvelder, J.S.; Manolarakis, S.A.; Hoek, van der J.P.; Paassen, van J.A.M.; Meer, van der W.G.J.; Agtmaal, van 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),

  11. Investigation of microbial communities on reverse osmosis membranes used for process water production

    NARCIS (Netherlands)

    Bereschenko, L.A.; Stams, A.J.M.; Heilig, G.H.J.; Euverink, G.J.W.; Nederlof, M.M.; Loosdrecht, M.C.M.

    2007-01-01

    In the present study, the diversity and the phylogenetic affiliation of bacteria in a biofouling layer on reverse osmosis (RO) membranes were determined. Fresh surface water was used as a feed in a membrane-based water purification process. Total DNA was extracted from attached cells from feed space

  12. Particulate and organic matter fouling of seawater reverse osmosis systems: Characterization, modelling and applications

    NARCIS (Netherlands)

    Salinas Rodriguez, S.G.

    2011-01-01

    Particulate/colloidal and organic fouling in seawater reverse osmosis (SWRO) systems results in flux decline, higher energy costs, increased salt passage, increased cleaning frequency, and use of chemicals. In practice, indices like SDI and MFI are used to assess particulate fouling, but they are

  13. Biofilm formation on reverse osmosis membranes is initiated and dominated by Sphingomonas spp

    NARCIS (Netherlands)

    Bereschenko, L.A.; Stams, A.J.M.; Euverink, G.J.W.; Loosdrecht, M.C.M.

    2010-01-01

    The initial formation and spatiotemporal development of microbial biofilm layers on surfaces of new and clean reverse osmosis (RO) membranes and feed-side spacers were monitored in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The feed water of th

  14. A survey of structure characterization methods for ultrafiltration and reverse osmosis membranes

    NARCIS (Netherlands)

    Smolders, C.A.; Mulder, M.H.V.; van der Velden, P.M.

    1976-01-01

    Asymmetric membranes consist of a thin skin, which is permselective to certain molecules in solution, and a porous support, serving as a mechanical support layer and also as a transport layer for the permeate. Both in ultrafiltration and in hyperfiltration (reverse osmosis) asymmetric membranes are

  15. Salinity-gradient power: Evaluation of pressure-retarded osmosis and reverse electrodialysis

    NARCIS (Netherlands)

    Post, J.W.; Veerman, J.; Hamelers, H.V.M.; Euverink, G.J.W.; Metz, S.J.; Nymeijer, K.; Buisman, C.J.N.

    2007-01-01

    A huge potential to obtain clean energy exists from mixing water streams with different salt concentrations. Two membrane-based energy conversion techniques are evaluated: pressure-retarded osmosis and reverse electrodialysis. From the literature, a comparison is not possible since the reported perf

  16. Application of pressure assisted forward osmosis for water purification and reuse of reverse osmosis concentrate from a water reclamation plant

    KAUST Repository

    Jamil, Shazad

    2016-07-26

    The use of forward osmosis (FO) is growing among the researchers for water desalination and wastewater treatment due to use of natural osmotic pressure of draw solute. In this study pressure assisted forward osmosis (PAFO) was used instead of FO to increase the water production rate. In this study a low concentration of draw solution (0.25 M KCl) was applied so that diluted KCl after PAFO operation can directly be used for fertigation. The performance of PAFO was investigated for the treatment of reverse osmosis concentrate (ROC) from a water reclamation plant. The water production in PAFO was increased by 9% and 29% at applied pressure of 2 and 4 bars, respectively, to feed side based on 90 h of experiments. Granular activated carbon (GAC) pretreatment and HCl softening were used to reduce organic fouling and scaling prior to application of PAFO. It reduced total organic carbon (TOC) and total inorganic carbon (TIC) by around 90% and 85%, respectively from untreated ROC. Subsequently, this led to an increase in permeate flux. In addition, GAC pretreatment adsorbed 12 out of 14 organic micropollutants tested from ROC to below detection limit. This application enabled to minimise the ROC volume with a sustainable operation and produced high quality and safe water for discharge or reuse. The draw solution (0.25 M KCl) used in this study was diluted to 0.14 M KCl, which is a suitable concentration (10 kg/m3) for fertigation, due to water transport from feed solution. © 2016 Elsevier B.V.

  17. Efficiently Combining Water Reuse and Desalination through Forward Osmosis-Reverse Osmosis (FO-RO) Hybrids: A Critical Review.

    Science.gov (United States)

    Blandin, Gaetan; Verliefde, Arne R D; Comas, Joaquim; Rodriguez-Roda, Ignasi; Le-Clech, Pierre

    2016-07-01

    Forward osmosis (FO) is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO) hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application) and water management challenges (proximity of wastewater and desalination plants), FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO) demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs) in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling.

  18. Addressing reverse osmosis fouling within water reclamation--a side-by-side comparison of low-pressure membrane pretreatments.

    Science.gov (United States)

    Kent, Fraser C; Farahbakhsh, Khosrow

    2011-06-01

    A tertiary membrane filtration (TMF) pilot operating on secondary effluent and a membrane bioreactor (MBR) were setup in a side-by-side study as pretreatments for two identical reverse osmosis pilot systems. The water quality of the permeate from both low-pressure membrane pretreatment systems and the fouling rate of the reverse osmosis systems were compared to assess the capabilities of the two low-pressure membrane pretreatments to prevent organic fouling of the reverse osmosis systems. Both pretreatment pilots were setup using typical operating conditions (i.e., solids retention time and mixed-liquor suspended solids). A consistent difference in water quality and reverse osmosis performance was demonstrated during the 12-month study. The MBR permeate consistently had significantly lower total organic carbon (TOC) and chemical oxygen demand concentrations, but higher color and specific UV absorbance compared with the permeate from the TMF pretreatment. The pretreatment with the MBR gave an average reverse osmosis fouling rate over the entire study (0.27 Lmh/bar.month) that was less than half of the value found for the reverse osmosis with TMF pretreatment (0.60 Lmh/bar.month). A correlation of reverse osmosis feed TOC concentration with average reverse osmosis fouling rate also was established, independent of the pretreatment method used. Results from a cleaning analysis, energy dispersive spectroscopy, and fourier transformed infrared reflectometry confirmed that the foulants were primarily organic in nature. It is concluded that, for this type of application and setup, MBR systems present an advantage over tertiary membrane polishing of secondary effluent for reverse osmosis pretreatment.

  19. Indirect desalination of Red Sea water with forward osmosis and low pressure reverse osmosis for water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-10-01

    The use of energy still remains the main component of the costs of desalting water. Forward osmosis (FO) can help to reduce the costs of desalination, and extracting water from impaired sources can be beneficial in this regard. Experiments with FO membranes using a secondary wastewater effluent as a feed water and Red Sea water as a draw solution demonstrated that the technology is promising. FO coupled with low pressure reverse osmosis (LPRO) was implemented for indirect desalination. The system consumes only 50% (~1.5 kWh/m3) of the energy used for high pressure seawater RO (SWRO) desalination (2.5-4 kWh/m3), and produces a good quality water extracted from the impaired feed water. Fouling of the FO membranes was not a major issue during long-term experiments over 14 days. After 10 days of continuous FO operation, the initial flux declined by 28%. Cleaning the FO membranes with air scouring and clean water recovered the initial flux by 98.8%. A cost analysis revealed FO per se as viable technology. However, a minimum average FO flux of 10.5 L/m2-h is needed to compete with water reuse using UF-LPRO, and 5.5 L/m2-h is needed to recover and desalinate water at less cost than SWRO. © 2011 Elsevier B.V.

  20. A Feasibility Study of Pressure Retarded Osmosis Power Generation System based on Measuring Permeation Volume using Reverse Osmosis Membrane

    Science.gov (United States)

    Enomoto, Hiroshi; Fujitsuka, Masashi; Hasegawa, Tomoyasu; Kuwada, Masatoshi; Tanioka, Akihiko; Minagawa, Mie

    Pressure Retarded Osmosis (PRO) power generation system is a hydroelectric power system which utilize permeation flow through a semi-permeable membrane. Permeation flow is generated by potential energy of salinity difference between sea water and fresh water. As membrane cost is expensive, permeation performance of membrane must be higher to realize PRO system. We have investigated Reverse Osmosis (RO) membrane products as semi-permeable membrane and measured permeation volume of a few products. Generation power by membrane area calculated from permeation volume is about 0.62W/m2. But by our improvements (more salt water volume, spacer of fresh water channel with a function of discharging concentrated salinity, extra low pressure type of membrane, washing support layer of membrane when generation power reduces to half), generation power may be 2.43W/m2. Then power system cost is about 4.1 million yen/kW. In addition, if support layer of membrane makes thinner and PRO system is applied to the equipment that pumping power on another purpose is avairable (wastewater treatment plant located at the seaside, thermal and nuclear power plant or sea water desalination plant), generation power may be more. By these improvements PRO system may be able to realize at the cost close to photovoltaic power system.

  1. Removal of radionuclides in drinking water by membrane treatment using ultrafiltration, reverse osmosis and electrodialysis reversal.

    Science.gov (United States)

    Montaña, M; Camacho, A; Serrano, I; Devesa, R; Matia, L; Vallés, I

    2013-11-01

    A pilot plant had been built to test the behaviour of ultrafiltration (UF), reverse osmosis (RO), and electrodialysis reversal (EDR) in order to improve the quality of the water supplied to Barcelona metropolitan area from the Llobregat River. This paper presents results from two studies to reduce natural radioactivity. The results from the pilot plant with four different scenarios were used to design the full-scale treatment plant built (SJD WTP). The samples taken at different steps of the treatment were analysed to determine gross alpha, gross beta and uranium activity. The results obtained revealed a significant improvement in the radiological water quality provided by both membrane techniques (RO and EDR showed removal rates higher than 60%). However, UF did not show any significant removal capacity for gross alpha, gross beta or uranium activities. RO was better at reducing the radiological parameters studied and this treatment was selected and applied at the full scale treatment plant. The RO treatment used at the SJD WTP reduced the concentration of both gross alpha and gross beta activities and also produced water of high quality with an average removal of 95% for gross alpha activity and almost 93% for gross beta activity at the treatment plant. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Forward Osmosis/Low Pressure Reverse Osmosis for Water Reuse: Removal of Organic Micropollutants, Fouling and Cleaning

    KAUST Repository

    Linares, Rodrigo

    2011-07-01

    Forward osmosis (FO) is a natural process in which a solution with high concentration of solutes is diluted when being in contact, through a semipermeable membrane, with a low concentration solution. This osmotic process has been demonstrated to be efficient to recover wastewater effluents while diluting a saline draw solution. Nevertheless, the study of the removal of micropollutants by FO is barely described in the literature. This research focuses on the removal of these substances spiked in a secondary wastewater effluent, while diluting water from the Red Sea, generating feed water that can be desalinated with a low pressure reverse osmosis (LPRO) system. Another goal of this work is to characterize the fouling of the FO membrane, and its effect on micropollutants rejection, as well as the membrane cleaning efficiency of different methods. When considering only FO with a clean membrane, the rejection of the hydrophilic neutral compounds was between 48.6% and 84.7%, for the hydrophobic neutrals the rejection ranged from 40.0% to 87.5%, and for the ionic compounds the rejections were between 92.9% and 96.5%. With a fouled membrane, the rejections were between 44.6% to 95.2%, 48.7% to 91.5% and 96.9% to 98.6%, respectively. These results suggest that, except for the hydrophilic neutral compounds, the rejection of the micropollutants is increased by the fouling layer, possibly due to the higher hydrophilicity of the FO fouled membrane compared to the clean one, the increased adsorption capacity and reduced mass transport capacity, membrane swelling, and the higher negative charge of the surface, related to the foulants. However, when coupled with low pressure reverse osmosis, the rejections for both, the clean and fouled membrane, increased above 98%. The fouling layer, after characterizing the wastewater effluent and the concentrated wastewater after the FO process, proved to be composed of biopolymers, which can be removed with air scouring during short periods

  3. Rejection of Emerging Organic Contaminants by Nanofiltration and Reverse Osmosis Membranes: Effects of Fouling, Modelling and Water Reuse

    NARCIS (Netherlands)

    Yangali Quintanilla, V.

    2010-01-01

    The book contains a description of the presence of micropollutants (medicines, hormones, pesticides) in surface water and shows that conventional water treatment poorly removes micropollutants. Nanofiltration and reverse osmosis are more appropriate technologies; however removals can vary depending

  4. Rejection of Emerging Organic Contaminants by Nanofiltration and Reverse Osmosis Membranes: Effects of Fouling, Modelling and Water Reuse

    NARCIS (Netherlands)

    Yangali Quintanilla, V.

    2010-01-01

    The book contains a description of the presence of micropollutants (medicines, hormones, pesticides) in surface water and shows that conventional water treatment poorly removes micropollutants. Nanofiltration and reverse osmosis are more appropriate technologies; however removals can vary depending

  5. Data on daily fluoride intake based on drinking water consumption prepared by household desalinators working by reverse osmosis process

    Directory of Open Access Journals (Sweden)

    Vahid Noroozi Karbasdehi

    2016-09-01

    Full Text Available In this data article, we evaluated the daily fluoride contents in 20 household desalinators working by reverse osmosis (RO1 Reverse Osmosis. process in Bushehr, Iran. The concentration levels of fluoride in inlet and outlet waters were determined by the standard SPADNS method using a spectrophotometer (M501 Single Beam Scanning UV/VIS, UK. The fluoride content in outlet waters were compared with EPA and WHO guidelines for drinking water.

  6. EFFICIENCY OF DOMESTIC REVERSE OSMOSIS IN REMOVAL OF TRIHALOMETHANES FROM DRINKING WATER

    Directory of Open Access Journals (Sweden)

    S. Mazloomi ، R. Nabizadeh ، S. Nasseri ، K. Naddafi ، S. Nazmara ، A. H. Mahvi

    2009-10-01

    Full Text Available The reaction of disinfectants with natural organic matters existing in water lead to the formation of Disinfection By-Products. Potentially hazardous and carcinogenic characteristics of trihalomethanes (THMs are recognized. Thus removal of THMs or its precursors are necessary for human health. The aim of this study was to study the efficiency of domestic reverse osmosis (RO in removal of trihalomethanes from drinking water. A pilot scale of RO system with Polyamide membrane as Spiral-Wound, Tape wrapping module was used. Feed solution was made by using of pure chloroform. The samples containing chloroform were analyzed using a gas chromatograph equipped with a flame ionization detector. By increasing the flow, the removal rate of chloroform decreased and with declining removal of EC, the removal of chloroform declined too. In this research, at the worst condition, the efficiency of the pilot scale reverse osmosis reached to 80 % removal of chloroform.

  7. Reverse osmosis filtration for space mission wastewater: membrane properties and operating conditions

    Science.gov (United States)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Reverse osmosis (RO) is a compact process that has potential for the removal of ionic and organic pollutants for recycling space mission wastewater. Seven candidate RO membranes were compared using a batch stirred cell to determine the membrane flux and the solute rejection for synthetic space mission wastewaters. Even though the urea molecule is larger than ions such as Na+, Cl-, and NH4+, the rejection of urea is lower. This indicates that the chemical interaction between solutes and the membrane is more important than the size exclusion effect. Low pressure reverse osmosis (LPRO) membranes appear to be most desirable because of their high permeate flux and rejection. Solute rejection is dependent on the shear rate, indicating the importance of concentration polarization. A simple transport model based on the solution-diffusion model incorporating concentration polarization is used to interpret the experimental results and predict rejection over a range of operating conditions. Grant numbers: NAG 9-1053.

  8. In situ characterization of fouling in reverse osmosis membranes using electrical impedance spectroscopy

    Science.gov (United States)

    Chilcott, Terry; Antony, Alice; Coster, Hans; Leslie, Greg

    2013-04-01

    Analytical solutions of the Nernst-Planck, Poisson and continuity equations for a membrane undergoing reverse osmosis in a cross-flow system reveal that the flow of alternating ionic charge induced in the membrane during impedance measurements is actively assisted by the flow of water. The actively driven current manifested "inductive" responses in impedance measurements of a Filmtec BW30 reverse osmosis membrane mounted in an Inphaze flat-bed cross-flow module after 16 hours of filtering a mineral salt solution seeded with CaCl2 and NaHCO3 at pressure of 900 kPa. Fitted transfer functions resolved conduction and capacitive properties of four membrane layers, diffusion/concentration phenomenon and a pseudo "inductor" shunted by a conductor. A 10-fold decrease in the shunt conductance correlated with smaller increases in the conductance values for the filtrate and membranous layers, and the onset of fouling diagnosed by a rapid increase in flux decline.

  9. MIMO Modeling Approach for a Small Photovoltaic Reverse Osmosis Desalination System

    Directory of Open Access Journals (Sweden)

    A.B Chaaben

    2011-01-01

    Full Text Available The most widely used desalination processes are based on membrane separation via reverse osmosis (RO which has become an important process for desalting seawater and cleaning brackish water. The use of these processes requires an efficient control system. Consequently, it is necessary to establish a dynamic model of the system with experimental validation. This paper deals with a new modelling approach of a small photovoltaic reverse osmosis (PV-RO desalination unit. The proposed model considers the unit as a Multi Input Multi Output (MIMO process. The relations between the output variables and the input variables are given by the use of empirical transfer matrix. A state model of the unit is also given. Some experimental results are presented to validate the proposed model. As result, the obtained unit model can be easily used for a process control loop implementation in order to assure an optimum operating condition and to reduce the water product cost.

  10. Reverse osmosis filtration for space mission wastewater: membrane properties and operating conditions

    Science.gov (United States)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Reverse osmosis (RO) is a compact process that has potential for the removal of ionic and organic pollutants for recycling space mission wastewater. Seven candidate RO membranes were compared using a batch stirred cell to determine the membrane flux and the solute rejection for synthetic space mission wastewaters. Even though the urea molecule is larger than ions such as Na+, Cl-, and NH4+, the rejection of urea is lower. This indicates that the chemical interaction between solutes and the membrane is more important than the size exclusion effect. Low pressure reverse osmosis (LPRO) membranes appear to be most desirable because of their high permeate flux and rejection. Solute rejection is dependent on the shear rate, indicating the importance of concentration polarization. A simple transport model based on the solution-diffusion model incorporating concentration polarization is used to interpret the experimental results and predict rejection over a range of operating conditions. Grant numbers: NAG 9-1053.

  11. Modeling of concentration polarization in a reverse osmosis channel with parabolic crossflow.

    Science.gov (United States)

    Liu, Cui; Morse, Audra; Rainwater, Ken; Song, Lianfa

    2014-01-01

    Concentration polarization in narrow reverse osmosis channels with parabolic crossflow was numerically simulated with finite different equations related to permeate velocity, crossflow velocity, average salt concentration, and wall salt concentration. A significant new theoretical development was the determination of two correction functions, F2 and F3, in the governing equation for average salt concentration. Simulations of concentration polarization under various conditions were then presented to describe the features of the new model as well as discussions about the differences of concentration polarizations of the more realistic parabolic flow with those when plug flow or shear flow was assumed. The situations in which the simpler models based on shear or plug flow can be used were indicated. Concentration polarization was also simulated for various conditions to show the applicability of the model and general features of concentration polarization in a narrow, long reverse osmosis channel.

  12. Reverse osmosis molecular differentiation of organic liquids using carbon molecular sieve membranes

    Science.gov (United States)

    Koh, Dong-Yeun; McCool, Benjamin A.; Deckman, Harry W.; Lively, Ryan P.

    2016-08-01

    Liquid-phase separations of similarly sized organic molecules using membranes is a major challenge for energy-intensive industrial separation processes. We created free-standing carbon molecular sieve membranes that translate the advantages of reverse osmosis for aqueous separations to the separation of organic liquids. Polymer precursors were cross-linked with a one-pot technique that protected the porous morphology of the membranes from thermally induced structural rearrangement during carbonization. Permeation studies using benzene derivatives whose kinetic diameters differ by less than an angstrom show kinetically selective organic liquid reverse osmosis. Ratios of single-component fluxes for para- and ortho-xylene exceeding 25 were observed and para- and ortho- liquid mixtures were efficiently separated, with an equimolar feed enriched to 81 mole % para-xylene, without phase change and at ambient temperature.

  13. AN ESTIMATE OF THE DETENTION IN THE PROCESS OF REVERSE OSMOSIS SEPARATION BIOLOGICAL SOLUTIONS BIOCHEMICAL INDUSTRIES

    Directory of Open Access Journals (Sweden)

    S. I. Lazarev

    2015-01-01

    Full Text Available Retained on a membrane solute in reverse osmosis separation of biological fluids at the surface of the membrane gradually accumulates and forms a boundary layer, where its concentration is higher than in the bulk. Increased concentration of solute in the solution at the membrane surface causes a diffusive flow of solids from the membrane surface into the bulk solution. After some time in the system t is a stationary state. A convective flow of solute to the membrane surface will be balanced by the sum of the fluxes of solute through the membrane and from the membrane surface into the bulk solution, i.e. in the case of concentration polarization is formed an edge of the diffusion layer. It is established that the concentration-polarization in reverse osmosis separation of the aqueous biological fluids biochemical production is influenced by the flow rate of solvent and the mass transfer coefficient. Experimental study allowed to characterize that by using the process of reverse osmosis can effectively divided, clear, and contaravati industrial solutions biochemical industries. Data at a rate of detention allow to evaluate the influence of concentration polarization on the efficiency of the reverse osmosis separation of industrial solutions. As a result of systematization and evaluation of experimental data and dependencies at a rate of detention found that with increasing the concentration, the rate of detention of solutes decreases. Based on the analysis and modification of the proposed equation for theoretical calculation of detention. Theoretical description of the coefficient detention accurately adequately calculated the modified equation N. V. Churaev, B. V. Deryaguin and V. M. Starov. The numerical values of the empirical coefficients, to calculate and predict the odds of arrest for a similar membrane separation processes industrial solutions. Values obtained correlation coefficients. The correlation coefficients specify that the rate of

  14. Composition and Variability of Biofouling Organisms in Seawater Reverse Osmosis Desalination Plants ▿ †

    OpenAIRE

    Zhang, Minglu; Jiang, Sunny; Tanuwidjaja, Dian; Voutchkov, Nikolay; Hoek, Eric M. V.; Cai, Baoli

    2011-01-01

    Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Ce...

  15. Particulate and organic matter fouling of seawater reverse osmosis systems: Characterization, modelling and applications

    OpenAIRE

    Salinas Rodriguez, S.G.

    2011-01-01

    Particulate/colloidal and organic fouling in seawater reverse osmosis (SWRO) systems results in flux decline, higher energy costs, increased salt passage, increased cleaning frequency, and use of chemicals. In practice, indices like SDI and MFI are used to assess particulate fouling, but they are performed at very high initial flux (> 1500 L/m2-h) and do not take into account the deposition of particles/colloids in RO systems. In this study, the Modified Fouling Index with ultrafiltration mem...

  16. Electrochemical treatment of concentrate from reverse osmosis of sanitary landfill leachate.

    Science.gov (United States)

    Labiadh, Lazhar; Fernandes, Annabel; Ciríaco, Lurdes; Pacheco, Maria José; Gadri, Abdellatif; Ammar, Salah; Lopes, Ana

    2016-10-01

    Conventional sanitary landfill leachate treatment has recently been complemented and, in some cases, completely replaced by reverse osmosis technology. Despite the good quality of treated water, the efficiency of the process is low and a large volume of reverse osmosis concentrate has to be either discharged or further treated. In this study, the use of anodic oxidation combined with electro-Fenton processes to treat the concentrate obtained in the reverse osmosis of sanitary landfill leachate was evaluated. The anodic oxidation pretreatment was performed in a pilot plant using an electrochemical cell with boron-doped diamond electrodes. In the electro-Fenton experiments, a boron-doped diamond anode and carbon-felt cathode were used, and the influence of the initial pH and iron concentration were studied. For the experimental conditions, the electro-Fenton assays performed at an initial pH of 3 had higher organic load removal levels, whereas the best nitrogen removal was attained when the electrochemical process was performed at the natural pH of 8.8. The increase in the iron concentration had an adverse impact on treatment under natural pH conditions, but it enhanced the nitrogen removal in the electro-Fenton assays performed at an initial pH of 3. The combined anodic oxidation and electro-Fenton process is useful for treating the reverse osmosis concentrate because it is effective at removing the organic load and nitrogen-containing species. Additionally, this process potentiates the increase in the biodegradability index of the treated effluent.

  17. Removal of Crotamiton from Reverse Osmosis Concentrate by a TiO2/Zeolite Composite Sheet

    OpenAIRE

    Qun Xiang; Shuji Fukahori; Naoyuki Yamashita; Hiroaki Tanaka; Taku Fujiwara

    2017-01-01

    Reverse osmosis (RO) concentrate from wastewater reuse facilities contains concentrated emerging pollutants, such as pharmaceuticals. In this research, a paper-like composite sheet consisting of titanium dioxide (TiO2) and zeolite was synthesized, and removal of the antipruritic agent crotamiton from RO concentrate was studied using the TiO2/zeolite composite sheet. The RO concentrate was obtained from a pilot-scale municipal secondary effluent reclamation plant. Effective immobilization of t...

  18. Composition and Variability of Biofouling Organisms in Seawater Reverse Osmosis Desalination Plants ▿ †

    OpenAIRE

    Zhang, Minglu; Jiang, Sunny; Tanuwidjaja, Dian; Voutchkov, Nikolay; Hoek, Eric M. V.; Cai, Baoli

    2011-01-01

    Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Ce...

  19. Particulate and organic matter fouling of seawater reverse osmosis systems: Characterization, modelling and applications

    OpenAIRE

    Salinas Rodriguez, S.G.

    2011-01-01

    Particulate/colloidal and organic fouling in seawater reverse osmosis (SWRO) systems results in flux decline, higher energy costs, increased salt passage, increased cleaning frequency, and use of chemicals. In practice, indices like SDI and MFI are used to assess particulate fouling, but they are performed at very high initial flux (> 1500 L/m2-h) and do not take into account the deposition of particles/colloids in RO systems. In this study, the Modified Fouling Index with ultrafiltration mem...

  20. Flux dependency of particulate/colloidal fouling in seawater reverse osmosis systems

    KAUST Repository

    Salinas Rodríguez, S. G.

    2012-01-01

    Fouling is the main operational problem in seawater reverse osmosis systems (SWRO). Particulate fouling is traditionally measured through the silt density index (SDI) and through the modified fouling index (MFI). In recent years, ultrafiltration membranes were used successfully at constant flux-MFI-UF-to measure particulate/colloidal fouling potential and tested in sea water applications. Furthermore, constant flux operation allows predicting the rate of fouling in RO systems. The objectives of this study are: (1) to measure the flux effect in MFI-UF with different membranes (100, 30 and 10 kDa) for raw seawater and pre-treated water before reverse osmosis in three different locations; (2) to study the particulate and colloidal fouling potential of seawater in reverse osmosis systems; (3) to project the increase in pressure due to cake resistance in reverse osmosis systems. In this research, flat ultrafiltration membranes (100, 50, 30 and 10 kDa) are used in a con- stant flux filtration mode to test and compare real seawaters from various locations (North and Mediterranean Sea) and from various full scale facilities including different pre-treatments (i.e., ultrafiltration and coagulation + dual media filtration). The operated fluxes range from 350 down to values close to real RO operation, 15l(m2h)-1. After each filtration test, the MFI-UF is calculated to assess the particulate fouling potential. The obtained results showed that: (1) the particulate and colloidal fouling potential is directly proportional to the applied flux during filtration. This proportionality is related to the compression of the cake deposit occurring at high flux values; (2) the higher the flux, the higher the required pressure, the less porous the cake and therefore the higher the specific cake resistance; (3) particulate and colloidal fouling potential of seawater is site specific and is influenced by pre-treatment. © 2012 Desalination Publications. All rights reserved.

  1. Concentration of pineapple juice by reverse osmosis: physicochemical characteristics and consumer acceptance

    Directory of Open Access Journals (Sweden)

    Daniel Simões Couto

    2011-12-01

    Full Text Available Reverse osmosis has been used for the concentration of fruit juices with promising considering the quality of the obtained products. The objective of this study was to concentrate single strength pineapple juice by reverse osmosis. The concentration was carried out with polyamide composite membranes in a 0.65 m² plate and frame module at 60 bar transmembrane pressure at 20 °C. The permeate flux was 17 L.hm-2. The total soluble solid content of the juice increased from 11 to 31 °Brix corresponding to a Volumetric Concentration Factor (VCF of 2.9. The concentration of soluble solids, total solids, and total acidity increased proportionally to FCV. The concentrated juice and three commercial concentrated pineapple juices were evaluated regarding preference and purchase intention by 79 pineapple juice consumers. The concentrated juice by reverse osmosis was the preferred among consumers. It can be concluded that this process may be considered an alternative to the pre-concentration of fruit juices.

  2. Separate and Concentrate Lactic Acid Using Combination of Nanofiltration and Reverse Osmosis Membranes

    Science.gov (United States)

    Li, Yebo; Shahbazi, Abolghasem; Williams, Karen; Wan, Caixia

    The processes of lactic acid production include two key stages, which are (a) fermentation and (b) product recovery. In this study, free cell of Bifidobacterium longum was used to produce lactic acid from cheese whey. The produced lactic acid was then separated and purified from the fermentation broth using combination of nanofiltration and reverse osmosis membranes. Nanofiltration membrane with a molecular weight cutoff of 100-400 Da was used to separate lactic acid from lactose and cells in the cheese whey fermentation broth in the first step. The obtained permeate from the above nanofiltration is mainly composed of lactic acid and water, which was then concentrated with a reverse osmosis membrane in the second step. Among the tested nanofiltration membranes, HL membrane from GE Osmonics has the highest lactose retention (97±1%). In the reverse osmosis process, the ADF membrane could retain 100% of lactic acid to obtain permeate with water only. The effect of membrane and pressure on permeate flux and retention of lactose/lactic acid was also reported in this paper.

  3. Efficiently Combining Water Reuse and Desalination through Forward Osmosis—Reverse Osmosis (FO-RO) Hybrids: A Critical Review

    OpenAIRE

    Gaetan Blandin; Verliefde, Arne R.D.; Joaquim Comas; Ignasi Rodriguez-Roda; Pierre Le-Clech

    2016-01-01

    Forward osmosis (FO) is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO) hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be ...

  4. Development and demonstration of a mobile reverse osmosis adsorption treatment system for environmental emergency clean-ups

    Energy Technology Data Exchange (ETDEWEB)

    1988-03-01

    A project was undertaken to develop and demonstrate a mobile reverse osmosis/adsorption system for treating water contaminated by organic chemicals. The system has two primary unit operations. The contaminated water is processed by reverse osmosis to produce a clean stream for discharge and a stream for further processing in which the organic contaminants have been concentrated up to 10 times their original concentration. The latter stream is treated in granular adsorbent columns where the contaminants are removed and an effluent suitable for discharge is produced. The contaminated water can be treated on-site and the contaminants can be removed from the site adsorbed on a relatively small amount of carbon. Field tests were conducted at two sites, one contaminated by leachate from a former chemical waste landfill and the other by drainage water from a petroleum and petrochemical transfer station. The 60-day demonstrations showed that reverse osmosis technology can be successfully used for treatment of water contaminated by toxic volatile organics and that granular activated carbon adsorption columns can be successfully used to remove those organics from the concentrate produced by reverse osmosis processing. However, the study also showed that the presence of significant quantities of suspended materials or Fe cause operational problems which limit the success of reverse osmosis processing under these conditions. These problems can be effectively addressed by adding an ultrafiltration pretreatment. 13 refs., 60 figs., 56 tabs.

  5. Hydrophilic, bactericidal nanoheater-enabled reverse osmosis membranes to improve fouling resistance.

    Science.gov (United States)

    Ray, Jessica R; Tadepalli, Sirimuvva; Nergiz, Saide Z; Liu, Keng-Ku; You, Le; Tang, Yinjie; Singamaneni, Srikanth; Jun, Young-Shin

    2015-06-03

    Polyamide (PA) semipermeable membranes typically used for reverse osmosis water treatment processes are prone to fouling, which reduces the amount and quality of water produced. By synergistically coupling the photothermal and bactericidal properties of graphene oxide (GO) nanosheets, gold nanostars (AuNS), and hydrophilic polyethylene glycol (PEG) on PA reverse osmosis membrane surfaces, we have dramatically improved fouling resistance of these membranes. Batch fouling experiments from three classes of fouling are presented: mineral scaling (CaCO3 and CaSO4), organic fouling (humic acid), and biofouling (Escherichia coli). Systematic analyses and a variety of complementary techniques were used to elucidate fouling resistance mechanisms from each layer of modification on the membrane surface. Both mineral scaling and organic fouling were significantly reduced in PA-GO-AuNS-PEG membranes compared to other membranes. The PA-GO-AuNS-PEG membrane was also effective in killing all near-surface bacteria compared to PA membranes. In the PA-GO-AuNS-PEG membrane, the GO nanosheets act as templates for in situ AuNS growth, which then facilitated localized heating upon irradiation by an 808 nm laser inactivating bacteria on the membrane surface. Furthermore, AuNS in the membrane assisted PEG in preventing mineral scaling on the membrane surface. In flow-through flux and foulant rejection tests, PA-GO-AuNS-PEG membranes performed better than PA membranes in the presence of CaSO4 and humic acid model foulants. Therefore, the newly suggested membrane surface modifications will not only reduce fouling from RO feeds, but can improve overall membrane performance. Our innovative membrane design reported in this study can significantly extend the lifetime and water treatment efficacy of reverse osmosis membranes to alleviate escalating global water shortage from rising energy demands.

  6. Reverse osmosis influence over the content of metals and organic acids in low alcoholic beverages

    Directory of Open Access Journals (Sweden)

    Andrieş Mitică Tiberiu

    2017-01-01

    Full Text Available Wine is defined as an alcoholic beverage resulted from fermentation of grape must, having ethanol content higher than 8.5% (v/v. Wine consumption has health benefits related to the high concentration of polyphenolic compounds with antioxidant activity and cardiovascular protection effects. However, the alcohol content restricts wine consumption, but wines with low-alcohol content can be obtained with the help of the dealcoholisation process, after it was produced through alcoholic fermentation. The purpose of this work is to evaluate the organic acid concentration, metal content and other physical-chemical parameters of low alcoholic beverages obtained from grape must by a process which involves reverse osmosis, mixing in a variable ratio the permeate and concentrate and then fermentation. For the experiments, a Muscat Ottonel grape must from Iaşi vineyard was used. There were ten variants of beverages (wines with low alcoholic concentration, by mixing known quantities of the two phases resulting from the reverse osmosis process. These beverages (wines had an alcoholic concentration starting from 2.5% (v/v in the first variant, up to 7% (v/v in the tenth variant. Alcoholic concentration varies for each variant by 0.5% (v/v. After fermentation in 50 L stainless steel tanks, the samples were filtered with 0.45μm sterile membrane and bottled in 0.75 L glass bottles. After 2 months of storage at constant temperature, the beverage samples were analyzed to determine the metal content (AAS method, organic acids concentration (HPLC method, and other physical-chemical characteristics (OIV standard methods. The results obtained indicate that the very complex physical-chemical composition of the low alcoholic beverages analyzed is influenced by the specific chemical composition of a given grape must, as well as by the use of products obtained from reverse osmosis.

  7. OPTIMASI DAN PEMODELAN PROSES RECOVER FLAVOR DARI LIMBAH CAIR INDUSTRI PENGOLAHAN RAJUNGAN DENGAN REVERSE OSMOSIS

    Directory of Open Access Journals (Sweden)

    Uju

    2009-04-01

    Full Text Available The waste water of blue crab pasteurization has potential in environmental pollution. It contained TSS of 206.5mg.1-1, BOD 7,092.6mg.1-1 and COD of 51,000mg.1-1. on the other hand, it also contains an interesting flavor compound, which composed of 0.23% non protein nitrogen and 17 amino acids where the highest was glutamic acid one. In this study, pre-filtration step using filter size 0.3 µ followed by reverse osmosis has been used to reduce these pollutions load and flavor compound recovery. During pre-filtration steps, TSS was reduced to 74.8% so turbidity decrased reased until 31%. After reverse osmosis process, BOD, and COD decreased more than 99%, and there was no amino acids detected in permeate stream. Factors that affect performance of reverse osmosis were transmembrane pressure, temperature and pH. The higher transmembrane pressure, temperature and pH resulted the higher the flux permeate. The use of higher temperature make flux increasing, eventually increasing transmembrane pressure make the flux increased only at transmembrane pressure less than 716 kPa. The protein rejection was influenced unsignifanctly by transmembrane pressure, temperature and pH. During concentrating flux declined exponentially by time function. At concentration factor 2.75 resulted 79% and 12% of increasing protein and NPN, respectively. The amino acids content can be increased 2−23 times of the origin. Even arginin and sistin, the amino acids that were undetectable initially, but they can bedetected at concentration of 0.0360 and 0.0250 (w/v respectively at the end of the process. Hidrolysis and fermentation process can increase the amino acid content 31−45 times

  8. Reverse osmosis for the recovery of boric acid from the primary coolant at nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Bártová, Šárka, E-mail: sarka.bartova@cvrez.cz [Research Centre Řež Ltd., Husinec-Řež 130, 250 68 Řež (Czech Republic); Kůs, Pavel [Research Centre Řež Ltd., Husinec-Řež 130, 250 68 Řež (Czech Republic); Skala, Martin [Research Centre Řež Ltd., Husinec-Řež 130, 250 68 Řež (Czech Republic); University of Chemical Technology, Prague, Department of Chemical Engineering, Technická 5, Prague 166 28 (Czech Republic); Vonková, Kateřina [Research Centre Řež Ltd., Husinec-Řež 130, 250 68 Řež (Czech Republic)

    2016-04-15

    Highlights: • RO membranes tested for boric acid recovery from primary coolant of nuclear power plants. • Scanning electron microscopy was used for the characterization of the membranes. • Lab scale experiments performed under various operation conditions. • We proposed configuration of and operation conditions for RO unit in nuclear power plant. - Abstract: At nuclear power plants (NPP), evaporators are used for the treatment of primary coolant and other liquid radioactive waste containing H{sub 3}BO{sub 3}. Because the operation of evaporators is expensive, a number of more cost-effective alternatives has been considered, one of which is reverse osmosis. We tested reverse osmosis modules from several manufactures on a batch laboratory apparatus. SEM images of the tested membranes were taken to distinguish the differences between the membranes. Water permeability through membranes was evaluated from the experiments with pure water. The experiments were performed with feed solutions containing various concentrations of H{sub 3}BO{sub 3} in a range commonly occurring in radioactive waste. The pH of the feed solutions ranged from 5.2 to 11.2. Our results confirmed that the pH of the feed solution plays the most important role in membrane separation efficiency of H{sub 3}BO{sub 3}. Certain modifications to the pH of the feed solution were needed to enable the tested membranes to concentrate the H{sub 3}BO{sub 3} in the retentate stream, separate from the pure water in the permeate stream. On this basis, we propose the configuration of and operational conditions for a reverse osmosis unit at NPP.

  9. The use of reverse osmosis at nuclear power plants. Replacement of evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Kus, Pavel; Bartova, Sarka; Kunesova, Katerina; Smejdova, Vladena; Vonkova, Katerina [Research Centre Rez, Husinec-Rez (Czech Republic). Technological Circuits

    2015-06-01

    Evaporators are being used in nuclear power plants for the treatment of primary coolant containing H3BO3 for neutron absorption and other components for adjusting water chemistry. The aim is to achieve a concentrated H3BO3 solution, which is further purified by ion exchangers and then recycled into the primary cycle. Operation of evaporators is expensive, therefore reverse osmosis was proposed as one promising alternative. A pilot-plant RO unit was used for the experiments performed with feed solution. The successful technology is now being implemented at Temelin NPP.

  10. Low-Fouling Antibacterial Reverse Osmosis Membranes via Surface Grafting of Graphene Oxide.

    Science.gov (United States)

    Huang, Xinwei; Marsh, Kristofer L; McVerry, Brian T; Hoek, Eric M V; Kaner, Richard B

    2016-06-15

    Azide-functionalized graphene oxide (AGO) was covalently anchored onto commercial reverse osmosis (RO) membrane surfaces via azide photochemistry. Surface modification was carried out by coating the RO membrane with an aqueous dispersion of AGO followed by UV exposure under ambient conditions. This simple process produces a hydrophilic, smooth, antibacterial membrane with limited reduction in water permeability or salt selectivity. The GO-RO membrane exhibited a 17-fold reduction in biofouling after 24 h of Escherichia coli contact and almost 2 times reduced BSA fouling after a 1 week cross-flow test compared to its unmodified counterpart.

  11. Domestic wash water reclamation for reuse as commode water supply using filtration: Reverse-osmosis separation technique

    Science.gov (United States)

    Hall, J. B., Jr.; Batten, C. E.; Wilkins, J. R.

    1974-01-01

    A combined filtration-reverse-osmosis water recovery system has been evaluated to determine its capability to reclaim domestic wash water for reuse as a commode water supply. The system produced water that met all chemical and physical requirements established by the U.S. Public Health Service for drinking water with the exception of carbon chloroform extractables, methylene blue active substances, and phenols. It is thought that this water is of sufficient quality to be reused as commode supply water. The feasibility of using a combined filtration and reverse-osmosis technique for reclaiming domestic wash water has been established. The use of such a technique for wash-water recovery will require a maintenance filter to remove solid materials including those less than 1 micron in size from the wash water. The reverse-osmosis module, if sufficiently protected from plugging, is an attractive low-energy technique for removing contaminants from domestic wash water.

  12. Analysis on Controlling the Scaling of Reverse Osmosis Membrane%反渗透膜结垢的控制分析

    Institute of Scientific and Technical Information of China (English)

    陈爱莲

    2014-01-01

    This paper introduced the reverse osmosis and its working principle, analyzed the reverse osmosis membrane scaling problem, and proposed some fouling prevention measures.%介绍反渗透及其工作原理,对反渗透膜结垢进行详细分析,并提出了预防结垢的措施。

  13. An investigation of desalination by nanofiltration, reverse osmosis and integrated (hybrid NF/RO) membranes employed in brackish water treatment.

    Science.gov (United States)

    Talaeipour, M; Nouri, J; Hassani, A H; Mahvi, A H

    2017-01-01

    As an appropriate tool, membrane process is used for desalination of brackish water, in the production of drinking water. The present study aims to investigate desalination processes of brackish water of Qom Province in Iran. This study was carried out at the central laboratory of Water and Wastewater Company of the studied area. To this aim, membrane processes, including nanofiltration (NF) and reverse osmosis (RO), separately and also their hybrid process were applied. Moreover, water physical and chemical parameters, including salinity, total dissolved solids (TDS), electric conductivity (EC), Na(+1) and Cl(-1) were also measured. Afterward, the rejection percent of each parameter was investigated and compared using nanofiltration and reverse osmosis separately and also by their hybrid process. The treatment process was performed by Luna domestic desalination device, which its membrane was replaced by two NF90 and TW30 membranes for nanofiltration and reverse osmosis processes, respectively. All collected brackish water samples were fed through membranes NF90-2540, TW30-1821-100(RO) and Hybrid (NF/RO) which were installed on desalination household scale pilot (Luna water 100GPD). Then, to study the effects of pressure on permeable quality of membranes, the simulation software model ROSA was applied. Results showed that percent of the salinity rejection was recorded as 50.21%; 72.82 and 78.56% in NF, RO and hybrid processes, respectively. During the study, in order to simulate the performance of nanofiltartion, reverse osmosis and hybrid by pressure drive, reverse osmosis system analysis (ROSA) model was applied. The experiments were conducted at performance three methods of desalination to remove physic-chemical parameters as percentage of rejections in the pilot plant are: in the NF system the salinity 50.21, TDS 43.41, EC 43.62, Cl 21.1, Na 36.15, and in the RO membrane the salinity 72.02, TDS 60.26, EC 60.33, Cl 43.08, Na 54.41. Also in case of the rejection

  14. Combined solar organic Rankine cycle with reverse osmosis desalination process: Energy, exergy, and cost evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Nafey, A.S.; Sharaf, M.A. [Department of Engineering Science, Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2010-11-15

    Organic Rankine cycles (ORC) have unique properties that are well suited to solar power generation. In this work design and performance calculations are performed using MatLab/SimuLink computational environment. The cycle consists of thermal solar collectors (Flat Plate Solar Collector (FPC), or Parabolic Trough Collector (PTC), or Compound Parabolic Concentrator (CPC)) for heat input, expansion turbine for work output, condenser unit for heat rejection, pump unit, and Reverse Osmosis (RO) unit. Reverse osmosis unit specifications used in this work is based on Sharm El-Shiekh RO desalination plant. Different working fluids such as: butane, isobutane, propane, R134a, R152a, R245ca, and R245fa are examined for FPC. R113, R123, hexane, and pentane are investigated for CPC. Dodecane, nonane, octane, and toluene are allocated for PTC. The proposed process units are modeled and show a good validity with literatures. Exergy and cost analysis are performed for saturation and superheated operating conditions. Exergy efficiency, total exergy destruction, thermal efficiency, and specific capital cost are evaluated for direct vapor generation (DVG) process. Toluene and Water achieved minimum results for total solar collector area, specific total cost and the rate of exergy destruction. (author)

  15. Toward a reverse osmosis membrane system for recycling space mission wastewater.

    Science.gov (United States)

    Lee, S; Lueptow, R M

    2000-01-01

    Essential to extended human exploration and utilization of space is providing a clean supply of potable water as well as water for washing. Recycling of space mission wastewater is necessary for long-term space missions due to the limited capacity of water storage. In this study, initial measurements toward a wastewater reclamation system that provides a clean water supply using reverse osmosis (RO) membranes have been made using stirred cell filtration experiments. Low-pressure reverse osmosis (LPRO) membranes were used to obtain high flux of permeate as well as high rejection. Detergent removal was above 99%, and dissolved salt removal was above 90% in single-pass treatment, while total organic carbon (TOC) removal was nearly 80%. Most problematic is nitrogen rejection, which was 74% at best. Comparison of feed water before and after urea hydrolysis shows that the rejection of nitrogen compounds can be increased to 95% by allowing urea hydrolysis to occur. The removal efficiency for nitrogen compounds was also improved by increasing the shear rate near membrane surface. As a result, the product water in two passes could meet the hygiene water requirements for human space missions, and the product water in three passes could meet potable water regulations with overall recovery of 77%. This study also suggests that dynamic rotating membrane filtration, which can produce a high shear rate, will be useful to increase the system recovery as well as pollutant rejection. Grant numbers: NAG9-1053

  16. Predicting and measurement of pH of seawater reverse osmosis concentrates

    KAUST Repository

    Waly, Tarek

    2011-10-01

    The pH of seawater reverse osmosis plants (SWRO) is the most influential parameter in determining the degree of supersaturation of CaCO3 in the concentrate stream. For this, the results of pH measurements of the concentrate of a seawater reverse osmosis pilot plant were compared with pH calculations based on the CO2-HCO3 --CO3 2- system equilibrium equations. Results were compared with two commercial software programs from membrane suppliers and also the software package Phreeqc. Results suggest that the real concentrate pH is lower than that of the feed and that none of the used programs was able to predict correctly real pH values. In addition, the effect of incorporating the acidity constant calculated for NaCl medium or seawater medium showed a great influence on the concentrate pH determination. The HCO3 - and CO3 2- equilibrium equation using acidity constants developed for seawater medium was the only method able to predict correctly the concentrate pH. The outcome of this study indicated that the saturation level of the concentrate was lower than previously anticipated. This was confirmed by shutting down the acid and the antiscalants dosing without any signs of scaling over a period of 12 months. © 2011 Elsevier B.V.

  17. Assessment of Silt Density Index (SDI) as Fouling Propensity Parameter in Reverse Osmosis Desalination

    KAUST Repository

    Rachman, Rinaldi

    2011-07-01

    Reverse osmosis operations are facing persistent fouling phenomenon that has challenged the integrity of these processes. Prediction of fouling potential by measuring a fouling index toward feed water is essential to ensure robust operation. Moreover, employing a reliable fouling index with good reproducibility and precision is necessary. Silt density index (SDI) is considered insufficient in terms of reliability and empirical theory, among other limitations. Nevertheless due its simplicity, SDI measurement is utilized extensively in RO desalination systems. The aim of this research is to assess the reliability of SDI. Methods include the investigation of different SDI membranes and study of the nature of the SDI filtration. Results demonstrate the existence of the membrane properties\\' variation within manufacturers, which then causes a lack of accuracy in fouling risk estimation. The nature of particles during SDI filtration provides information that particle concentration and size play a significant role on SDI quantification with substantial representation given by particles with size close to membrane nominal pore size. Moreover, turbidity assisted SDI measurements along with determination of UF pretreated and clean water fouling potential, establishes the indication of non-fouling related phenomena involved on SDI measurement such as a natural organic matter adsorption and hydrodynamic condition that alters during filtration. Additionally, it was found that the latter affects the sensitivity of SDI by being represented by some portions of SDI value. Keywords: Reverse Osmosis, Fouling index, Particulate Fouling, Silt Density Index (SDI), and Assessment of SDI.

  18. Surface modification of seawater desalination reverse osmosis membranes: Characterization studies & performance evaluation

    KAUST Repository

    Matin, Asif

    2014-06-01

    In this work we report surface modification of commercial reverse osmosis membranes by depositing ultrathin copolymer coatings, which could potentially enhance the biofouling resistance of RO membranes. Hydrophilic monomer hydroxyethyl methacrylate (HEMA) and a hydrophobic monomer, perfluorodecyl acrylate (PFDA) were copolymerized directly on the active layer of commercial aromatic polyamide reverse osmosis (RO) membranes using an initiated Chemical Vapor Deposition (iCVD) technique. Attenuated total reflective Fourier transform infrared spectra (ATR-FTIR) verified the successful modification of the membrane surfaces as a new FTIR adsorption band around 1730cm-1 corresponding to carbonyl groups in the copolymer film appeared after the deposition. X-ray Photoelectron spectroscopy (XPS) analysis also confirmed the presence of the copolymer film on the membrane surface by showing strong fluorine peaks emanating from the fluorinated alkyl side chains of the PFA molecules. Contact angle measurements with deionized water showed the modified membrane surfaces to be initially very hydrophobic but quickly assumed a hydrophilic character within few minutes. Atomic Force Microscopy (AFM) revealed that the deposited films were smooth and conformal as the surface topology of the underlying membrane surface remained virtually unchanged after the deposition. FESEM images of the top surface also showed that the typical ridge-and-valley structure associated with polyamide remained intact after the deposition. Short-term permeation tests using DI water and 2000ppm NaCl water showed that the deposited copolymer coatings had negligible effect on permeate water flux and salt rejection. © 2013 Elsevier B.V.

  19. Size fractionation characterisation of removed organics in reverse osmosis concentrates by ferric chloride.

    Science.gov (United States)

    Bagastyo, A Y; Keller, J; Batstone, D J

    2011-01-01

    Reverse osmosis membrane separation is the leading method for manufacturing potable purified water. It also produces a concentrate stream, namely reverse osmosis concentrates (ROC), with 10-20% of the water, and almost all other compounds. One method for further treating this stream is by coagulation with ferric chloride. This study evaluates removed organics in ROC treated with ferric chloride. Fractionation with ultrafiltration membranes allows separation of organics based on a nominal molecular weight. A stirred cell system was applied for serial fractionation to classify organic compounds into six groups of 10 kDa. The study found that raw ROC is rich in low molecular weight compounds (organics. These compounds include soluble microbial products (SMPs) and smaller humic and fulvic acids as indicated by fluorescence scanning. Conversely, colour was mostly contributed by medium to large molecules of humic and fulvic acids (> 0.5 kDa). Organics and colour were reduced in all molecular groups at an optimum treatment dose 1.48 mM FeCl3 and a pH of 5. However, ferric seemed to effectively remove colour in all size ranges while residual nitrogen was found mostly in the < 1 kDa sizes. Further, the fluorescence indicated that larger humic and fulvic acids were removed with considerable SMPs remaining in the < 0.5 kDa.

  20. Energy efficiency of batch and semi-batch (CCRO) reverse osmosis desalination.

    Science.gov (United States)

    Warsinger, David M; Tow, Emily W; Nayar, Kishor G; Maswadeh, Laith A; Lienhard V, John H

    2016-12-01

    As reverse osmosis (RO) desalination capacity increases worldwide, the need to reduce its specific energy consumption becomes more urgent. In addition to the incremental changes attainable with improved components such as membranes and pumps, more significant reduction of energy consumption can be achieved through time-varying RO processes including semi-batch processes such as closed-circuit reverse osmosis (CCRO) and fully-batch processes that have not yet been commercialized or modelled in detail. In this study, numerical models of the energy consumption of batch RO (BRO), CCRO, and the standard continuous RO process are detailed. Two new energy-efficient configurations of batch RO are analyzed. Batch systems use significantly less energy than continuous RO over a wide range of recovery ratios and source water salinities. Relative to continuous RO, models predict that CCRO and batch RO demonstrate up to 37% and 64% energy savings, respectively, for brackish water desalination at high water recovery. For batch RO and CCRO, the primary reductions in energy use stem from atmospheric pressure brine discharge and reduced streamwise variation in driving pressure. Fully-batch systems further reduce energy consumption by not mixing streams of different concentrations, which CCRO does. These results demonstrate that time-varying processes can significantly raise RO energy efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Evaluation of the use of reverse osmosis to eliminate natural radionuclides from water samples.

    Science.gov (United States)

    Nieto, Antonio; Palomo, Marta; Ruana, Josep; Peñalver, Alejandra; Aguilar, Carme; Borrull, Francesc

    2013-12-01

    The objective of drinking water treatment plants (DWTP) is to supply the population with tap water that is in optimal condition and in compliance with water quality regulations. In the DWTP of L'Ampolla (Tarragona, Spain), slightly high values of gross alpha activity and the amount of salts in the raw water have been observed. Conventional treatment has reduced these levels only minimally. This study tested a tertiary treatment based on reverse osmosis is tested in an industrial pilot plant (240 m3/day) The efficiency of this pilot plant to reduce the gross alpha and beta activities and the activity of some individual radioisotopes (U(238), U(234), U(235) and Ra(226)) was tested. Results showed that the elimination of alpha emitters was greater than 90%, whereas the elimination of beta emitters was about 35%. Overall, the data provided evidence that the pilot plant is effective for removing different radionuclides that can be present in the incoming water treated. Therefore, tertiary treatment based on reverse osmosis has a positive effect in water quality.

  2. Performances of nanofiltration and low pressure reverse osmosis membranes for desalination: characterization and modelling

    Science.gov (United States)

    Boussouga, Y. A.; Lhassani, A.

    2017-03-01

    The nanofiltration and the reverse osmosis processes are the most common techniques for the desalination of water contaminated by an excess of salts. In this present study, we were interested in the characterization of commercial, composite and asymmetric membranes of nanofiltration (NF90, NF270) and low pressure reverse osmosis (BW30LE). The two types of characterization that we opted for our study: (i) characterization of electrical proprieties, in terms of the surface charge of various membranes studied by the measurement of the streaming potential, (ii) hydrodynamic characterization in terms of hydraulic permeability with pure water, mass transfer and phenomenological parameters for each system membrane/salt using hydrodynamic approaches. The irreversible thermodynamics allowed us to model the observed retention Robs of salts (NaCl and Na2SO4) for the different membranes studied, to understand and to predict a good filtration with a membrane. A study was conducted on the type of mass transfer for each system membrane/salt: convection and diffusion. The results showed that all tested membranes are negatively charged for the solutions at neutral pH, this is explained by their material composition. The results also showed competitiveness between the different types of membranes. In view of that the NF remains effective in terms of selective retention with less energy consumption than LPRO.

  3. Salt transport properties of model reverse osmosis membranes using electrochemical impedance spectroscopy

    Science.gov (United States)

    Feldman, Kathleen; Chan, Edwin; Stafford, Gery; Stafford, Christopher

    With the increasing shortage of clean water, efficient purification technologies including membrane separations are becoming critical. The main requirement of reverse osmosis in particular is to maximize water permeability while minimizing salt permeability. Such performance optimization has typically taken place through trial and error approaches. In this work, key salt transport metrics are instead measured in model reverse osmosis membranes using electrochemical impedance spectroscopy (EIS). As shown previously, EIS can provide both the membrane resistance Rm and membrane capacitance Cm, with Rm directly related to salt permeability. The membranes are fabricated in a molecular layer by layer approach, which allows for control over such parameters as thickness, surface and bulk chemistry, and network geometry/connectivity. Rm, and therefore salt permeability, follows the expected trends with thickness and membrane area but shows unusual behavior when the network geometry is systematically varied. By connecting intrinsic material properties such as the salt permeability with macroscopic performance measures we can begin to establish design rules for improving membrane efficiency and facilitate the creation of next-generation separation membranes.

  4. STUDIES ON REVERSE OSMOSIS SEPARATION OF AQUEOUS ORGANIC SOLUTIONS BY PAA/PSF COMPOSITE MEMBRANE

    Institute of Scientific and Technical Information of China (English)

    Jun Fang; De-min Jia; Ji-cai Huang; Qun-hui Guo; Feng-lian Wu

    2000-01-01

    The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids,ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. It was found that the separation results for aliphatic alcohols, amines and aldehydes are satisfactory, the solute rejection (Ra) and the volume fluxes of solutions (Jr) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2%, 61.0%, 84.0% and 0.90×alcohols, amines and aldehydes, and the Ra for n-amyl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6%and 96.0%, respectively. Satisfactory separation results (Ra>70%) for ketones, esters, phenols and polyols have been obtained with the PAA/PSF composite membrane. The effect of operating pressure on the properties of reverse osmosis has also been investigated. Analysis of experimental data with Spiegler-Kedem's transport model has been carried out and the membrane constants such as reflection coefficient σ, solute and hydraulic permeabilities ω and Lp for several organic solutes have been obtained.

  5. Reducing the environmental impacts of reverse osmosis desalination by using brackish groundwater resources.

    Science.gov (United States)

    Muñoz, Ivan; Fernández-Alba, Amadeo Rodríguez

    2008-02-01

    The aim of the present work is to find out whether or not, and to what extent, the environmental impacts of reverse osmosis desalination are reduced when brackish groundwater is used instead of sea water. In order to answer this question, the Life-Cycle Assessment (LCA) methodology is used, and two water production plants are compared. The brackish groundwater scenario is based on a plant located in Almería (southern Spain), while the sea water scenario is based on literature data. Four impact categories and two environmental indicators, one of them related to brine discharge, are included. The results show that the key life-cycle issue of brackish groundwater desalination is electricity consumption, and since this is substantially reduced with regard to using sea water, the life-cycle impacts are found to be almost 50% lower. An uncertainty analysis based on Monte-Carlo simulation shows that these environmental savings are significant for all impact categories. Potential local impacts provoked by brine discharge are also found to be lower, due to a reduced content of salts. It is concluded that, when and wherever possible, exploitation of brackish groundwater resources should be assigned priority to sea water resources as an input for reverse osmosis desalination, although it must be taken into account that groundwater, as opposed to sea water, is a limited resource.

  6. Treatment of dairy effluent model solutions by nanofiltration and reverse osmosis

    Directory of Open Access Journals (Sweden)

    I. Kyrychuk

    2015-05-01

    Full Text Available Introduction. Dairy industry generates a large amount of wastewaters that have high concentrations and contain milk components. Membrane processes have been shown to be convenient for wastewater treatment recovering milk components present in wastewaters and producing treated water. Materials and methods. The experiments were carried out in an unstirred batch sell using nanofiltration membranes OPMN-P (ZAO STC “Vladipor”, Russian Federation and reverse osmosis membranes NanoRo, ZAO (“RM Nanotech”, Russian Federation. The model solutions of dairy effluents –diluted skim and whole milk were used. Results. The nanofiltration and reverse osmosis membranes showed the same permeate flux during the concentration of model solutions of dairy effluents. The reason of this was likely membrane fouling with feed components. The fouling indexes indicated the fouling factor that was higher for RO. The higher permeate quality was obtainedwith RO membranes. The NF permeate containing up to 0.4 g/L of lactose and 0.75 g/L of mineral salts can be discharged or after finishing trеatment (e.g. RO or other can be reused. The obtained NF and RO retentate corresponds to milk in composition and can be used for non-food applications or as feed supplement for animals. Conclusions.The studied RO and NF membranes can be used for concentration of dairy effluents at low pressure. They showed better performance and separation characteristics comparing with data of other membranes available in the literature.

  7. Inability of Microorganisms To Degrade Cellulose Acetate Reverse-Osmosis Membranes †

    Science.gov (United States)

    Ho, Leighton C. W.; Martin, David D.; Lindemann, William C.

    1983-01-01

    Operational cellulose acetate reverse-osmosis membranes were examined for evidence of biological degradation. Numerous fungi and bacteria were isolated by direct and enrichment techniques. When tested, most of the fungi were active cellulose degraders, but none of the bacteria were. Neither fungi nor bacteria were able to degrade cellulose acetate membrane in vitro, although many fungi were able to degrade cellulose acetate membrane after it had been deacetylated. Organisms did not significantly degrade powdered cellulose acetate in pure or mixed cultures as measured by reduction in acetyl content or intrinsic viscosity or production of reducing sugars. Organisms did not affect the performance of cellulose triacetate fibers when incubated with them. The inability of the organisms to degrade cellulose acetate was attributed to the high degree of acetate substitution of the cellulose polymer. The rate of salt rejection decline was strongly correlated with chlorination of feed water and inversely with densities of microorganisms. These data suggest that microbial degradation of operational cellulose acetate reverse-osmosis membranes is unlikely. PMID:16346192

  8. Comparison of methods for assessing reverse osmosis membrane treatment of shrimp process water.

    Science.gov (United States)

    Casani, Sandra; Hansen, Tina B; Christensen, Jakob; Knøchel, Susanne

    2005-04-01

    Interest in reuse of process water from the food industry has reinforced the importance of controlling and monitoring the effectiveness and reliability of treatment systems regarding removal of organic matter and microorganisms. The ability of adenosine triphosphate bioluminescence, conductivity, turbidometry, absorbance, and multichannel fluorescence spectroscopy for indirectly monitoring the integrity of a reverse osmosis membrane when treating process water recovered from peeling in a shrimp processing line was evaluated. This study demonstrated that reverse osmosis was capable of removing bacteria (ca. 7 log CFU ml(-1)) to the levels required by the regulatory authorities for water recycling within the same food unit operation. Adenosine triphosphate and turbidometry showed a higher sensitivity for detecting compromising conditions at the treatment system (0.1% concentration of feed in permeate) and a better correlation with the aerobic count at lower levels than the other methods investigated. The sensitivity for assessing membrane integrity of conductivity and multichannel fluorescence was 1% of feed in permeate. Impact of feed variations was best leveled out in the permeates for turbidity measurements. Multichannel fluorescence spectroscopy may require laborious calibration procedures and expertise regarding data analysis and interpretation of results, which are not always available in food industries. Absorbance did not respond to changes in membrane integrity and was not well correlated to the aerobic count because of the poor sensitivity of this method for these purposes.

  9. Model Predictive Control of the Reverse Osmosis Plant at AICA Laboratories

    Directory of Open Access Journals (Sweden)

    Ana Isabel González Santos

    2014-09-01

    Full Text Available Process control is an essential part of the desalination industry that requires to be controlled at theoptimum operating conditions to guarantee an increase in the life time of the plant and reduction of theunit product cost. Desalination is a highly complex process, so the majority of dynamic models are ofthe form of Multi-Inputs-Multi-Outputs (MIMO systems. Controlling a MIMO system is a complexoperation because of the interconnections between the inputs and the influence of each one of them onthe system outputs. In this paper, we present the MIMO dynamic model that was developed for a twostageReverse Osmosis (RO desalination system at AICA Laboratories. The purpose of this researchwas to apply a new control strategy to the system based on a Model Predictive Control (MPC algorithm.The control system proposed was simulated through computer by using Simulink/Matlab software.The simulation results show the efficiency of the proposed controller based on MPC strategy and canbe useful to increase knowledge in control processes in reverse osmosis desalination systems.

  10. Study of the effectiveness of polyamide reverse osmosis membranes in the recovery of Cr(III) in tanning. Estudio sobre la efectividad de las membranas de osmosis inversa de poliamida en la recuperacion de Cr(III) en curticion

    Energy Technology Data Exchange (ETDEWEB)

    Galan, M.; Gonzalez, C.; Llorens, J.; Mans, C. (Barcelona Univ., Tarragona (Spain). Dept. d' Enginyeria Quimica i Bioqumica)

    1992-12-01

    Laboratory experiments on reverse osmosis using water containing Cr2(SO4)3 and a Film Tech Corporation TW30-2514 membrane are described. The type of cell employed allowed the membrane's rejection of Cr(III) to be measured with a high degree of accuracy. Tests were carried out varying the Cr concentration, the pressure and the temperature. The results obtained have implications regarding the suitability of reverse osmosis in recovering Cr from tanning waste water. (Author)

  11. Bioluminescence-based method for measuring assimilable organic carbon in pretreatment water for reverse osmosis membrane desalination.

    Science.gov (United States)

    Weinrich, Lauren A; Schneider, Orren D; LeChevallier, Mark W

    2011-02-01

    A bioluminescence-based assimilable organic carbon (AOC) test was developed for determining the biological growth potential of seawater within the reverse osmosis desalination pretreatment process. The test uses Vibrio harveyi, a marine organism that exhibits constitutive luminescence and is nutritionally robust. AOC was measured in both a pilot plant and a full-scale desalination plant pretreatment.

  12. Ozone and biofiltration as an alternative to reverse osmosis for removing PPCPs and micropollutants from treated wastewater

    DEFF Research Database (Denmark)

    Lee, Carson; Howe, Kerry J.; Thomson, Bruce M.

    2012-01-01

    This pilot-scale research project investigated and compared the removal of pharmaceuticals and personal care products (PPCPs) and other micropollutants from treated wastewater by ozone/biofiltration and reverse osmosis (RO). The reduction in UV254 absorbance as a function of ozone dose correlated...

  13. Speech and Language Disorders in a Dialysis Encephalopathy Patient and the Effect of Desferrioxamine and Reverse-Osmosis Water Treatment.

    Science.gov (United States)

    Lehtihalmes, Matti; And Others

    Dialysis encephalopathy is a progressive neurological disorder occurring after long-term hemodialysis in some renal failure patients. Accumulation of aluminum in the brain is suspected as its cause, and the use of reverse osmosis of the dialysis water and administration of desferrioxamine to the patient have been successful in reducing the…

  14. Bioluminescence-Based Method for Measuring Assimilable Organic Carbon in Pretreatment Water for Reverse Osmosis Membrane Desalination ▿

    Science.gov (United States)

    Weinrich, Lauren A.; Schneider, Orren D.; LeChevallier, Mark W.

    2011-01-01

    A bioluminescence-based assimilable organic carbon (AOC) test was developed for determining the biological growth potential of seawater within the reverse osmosis desalination pretreatment process. The test uses Vibrio harveyi, a marine organism that exhibits constitutive luminescence and is nutritionally robust. AOC was measured in both a pilot plant and a full-scale desalination plant pretreatment. PMID:21148685

  15. Teaching Mass Transfer and Filtration Using Crossflow Reverse Osmosis and Nanofiltration: An Experiment for the Undergraduate Unit Operations Lab

    Science.gov (United States)

    Anastasio, Daniel; McCutcheon, Jeffrey

    2012-01-01

    A crossflow reverse osmosis (RO) system was built for a senior-level chemical engineering unit operations laboratory course. Intended to teach students mass transfer fundamentals related to membrane separations, students tested several commercial desalination membranes, measuring water flux and salt rejections at various pressures, flow rates, and…

  16. Teaching Mass Transfer and Filtration Using Crossflow Reverse Osmosis and Nanofiltration: An Experiment for the Undergraduate Unit Operations Lab

    Science.gov (United States)

    Anastasio, Daniel; McCutcheon, Jeffrey

    2012-01-01

    A crossflow reverse osmosis (RO) system was built for a senior-level chemical engineering unit operations laboratory course. Intended to teach students mass transfer fundamentals related to membrane separations, students tested several commercial desalination membranes, measuring water flux and salt rejections at various pressures, flow rates, and…

  17. Speech and Language Disorders in a Dialysis Encephalopathy Patient and the Effect of Desferrioxamine and Reverse-Osmosis Water Treatment.

    Science.gov (United States)

    Lehtihalmes, Matti; And Others

    Dialysis encephalopathy is a progressive neurological disorder occurring after long-term hemodialysis in some renal failure patients. Accumulation of aluminum in the brain is suspected as its cause, and the use of reverse osmosis of the dialysis water and administration of desferrioxamine to the patient have been successful in reducing the…

  18. Experience gained from operation of the reverse-osmosis plant at the Novosibirsk TETs-2 cogeneration station

    Science.gov (United States)

    Abramova, I. A.; Chernov, S. A.; Maikov, V. M.; Doineko, O. A.; Ustinov, B. V.; Vil'Ms, E. V.

    2008-05-01

    We present the main indicators characterizing the performance of the demineralizing plant comprising reverse-osmosis and ion-exchange equipment that produces makeup water for the boilers at the Novosibirsk TETs-2 cogeneration station for three years of plant operation.

  19. Effect of conventional chemical treatment on the microbial population in a biofouling layer of reverse osmosis systems

    NARCIS (Netherlands)

    Bereschenko, L.A.; Prummel, H.; Euverink, G.J.W.; Stams, A.J.M.; Loosdrecht, M.C.M. van

    2011-01-01

    The impact of conventional chemical treatment on initiation and spatiotemporal development of biofilms on reverse osmosis (RO) membranes was investigated in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The flow cells got the same feed (extensivel

  20. Effect of conventional chemical treatment on the microbial population in a biofouling layer of reverse osmosis systems

    NARCIS (Netherlands)

    Bereschenko, L.A.; Prummel, H.; Euverink, G.J.W.; Stams, A.J.M.; Loosdrecht, M.C.M. van

    2011-01-01

    The impact of conventional chemical treatment on initiation and spatiotemporal development of biofilms on reverse osmosis (RO) membranes was investigated in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The flow cells got the same feed (extensivel

  1. Economic Evaluation of a Hybrid Desalination System Combining Forward and Reverse Osmosis.

    Science.gov (United States)

    Choi, Yongjun; Cho, Hyeongrak; Shin, Yonghyun; Jang, Yongsun; Lee, Sangho

    2015-12-29

    This study seeks to evaluate the performance and economic feasibility of the forward osmosis (FO)-reverse osmosis (RO) hybrid process; to propose a guideline by which this hybrid process might be more price-competitive in the field. A solution-diffusion model modified with film theory was applied to analyze the effects of concentration polarization, water, and salt transport coefficient on flux, recovery, seawater concentration, and treated wastewater of the FO process of an FO-RO hybrid system. A simple cost model was applied to analyze the effects of flux; recovery of the FO process; energy; and membrane cost on the FO-RO hybrid process. The simulation results showed that the water transport coefficient and internal concentration polarization resistance are very important factors that affect performance in the FO process; however; the effect of the salt transport coefficient does not seem to be large. It was also found that the flux and recovery of the FO process, the FO membrane, and the electricity cost are very important factors that influence the water cost of an FO-RO hybrid system. This hybrid system can be price-competitive with RO systems when its recovery rate is very high, the flux and the membrane cost of the FO are similar to those of the RO, and the electricity cost is expensive. The most important thing in commercializing the FO process is enhancing performance (e.g.; flux and the recovery of FO membranes).

  2. Economic Evaluation of a Hybrid Desalination System Combining Forward and Reverse Osmosis

    Science.gov (United States)

    Choi, Yongjun; Cho, Hyeongrak; Shin, Yonghyun; Jang, Yongsun; Lee, Sangho

    2015-01-01

    This study seeks to evaluate the performance and economic feasibility of the forward osmosis (FO)–reverse osmosis (RO) hybrid process; to propose a guideline by which this hybrid process might be more price-competitive in the field. A solution-diffusion model modified with film theory was applied to analyze the effects of concentration polarization, water, and salt transport coefficient on flux, recovery, seawater concentration, and treated wastewater of the FO process of an FO-RO hybrid system. A simple cost model was applied to analyze the effects of flux; recovery of the FO process; energy; and membrane cost on the FO-RO hybrid process. The simulation results showed that the water transport coefficient and internal concentration polarization resistance are very important factors that affect performance in the FO process; however; the effect of the salt transport coefficient does not seem to be large. It was also found that the flux and recovery of the FO process, the FO membrane, and the electricity cost are very important factors that influence the water cost of an FO-RO hybrid system. This hybrid system can be price-competitive with RO systems when its recovery rate is very high, the flux and the membrane cost of the FO are similar to those of the RO, and the electricity cost is expensive. The most important thing in commercializing the FO process is enhancing performance (e.g.; flux and the recovery of FO membranes). PMID:26729176

  3. Phosphorus and water recovery by a novel osmotic membrane bioreactor-reverse osmosis system.

    Science.gov (United States)

    Luo, Wenhai; Hai, Faisal I; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2016-01-01

    An osmotic membrane bioreactor-reverse osmosis (OMBR-RO) hybrid system integrated with periodic microfiltration (MF) extraction was evaluated for simultaneous phosphorus and clean water recovery from raw sewage. In this hybrid system, the forward osmosis membrane effectively retained inorganic salts and phosphate in the bioreactor, while the MF membrane periodically bled them out for phosphorus recovery with pH adjustment. The RO process was used for draw solute recovery and clean water production. Results show that phosphorus recuperation from the MF permeate was most effective when the solution pH was adjusted to 10, whereby the recovered precipitate contained 15-20% (wt/wt) of phosphorus. Periodic MF extraction also limited salinity build-up in the bioreactor, resulting in a stable biological performance and an increase in water flux during OMBR operation. Despite the build-up of organic matter and ammonia in the draw solution, OMBR-RO allowed for the recovery of high quality reused water.

  4. Economic Evaluation of a Hybrid Desalination System Combining Forward and Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    Yongjun Choi

    2015-12-01

    Full Text Available This study seeks to evaluate the performance and economic feasibility of the forward osmosis (FO–reverse osmosis (RO hybrid process; to propose a guideline by which this hybrid process might be more price-competitive in the field. A solution-diffusion model modified with film theory was applied to analyze the effects of concentration polarization, water, and salt transport coefficient on flux, recovery, seawater concentration, and treated wastewater of the FO process of an FO-RO hybrid system. A simple cost model was applied to analyze the effects of flux; recovery of the FO process; energy; and membrane cost on the FO-RO hybrid process. The simulation results showed that the water transport coefficient and internal concentration polarization resistance are very important factors that affect performance in the FO process; however; the effect of the salt transport coefficient does not seem to be large. It was also found that the flux and recovery of the FO process, the FO membrane, and the electricity cost are very important factors that influence the water cost of an FO-RO hybrid system. This hybrid system can be price-competitive with RO systems when its recovery rate is very high, the flux and the membrane cost of the FO are similar to those of the RO, and the electricity cost is expensive. The most important thing in commercializing the FO process is enhancing performance (e.g.; flux and the recovery of FO membranes.

  5. Asymmetrical reverse vortex flow due to induced-charge electro-osmosis around carbon stacking structures

    Science.gov (United States)

    Sugioka, Hideyuki

    2011-05-01

    Broken symmetry of vortices due to induced-charge electro-osmosis (ICEO) around stacking structures is important for the generation of a large net flow in a microchannel. Following theoretical predictions in our previous study, we herein report experimental observations of asymmetrical reverse vortex flows around stacking structures of carbon posts with a large height (~110 μm) in water, prepared by the pyrolysis of a photoresist film in a reducing gas. Further, by the use of a coupled calculation method that considers boundary effects precisely, the experimental results, except for the problem of anomalous flow reversal, are successfully explained. That is, unlike previous predictions, the precise calculations here show that stacking structures accelerate a reverse flow rather than suppressing it for a microfluidic channel because of the deformation of electric fields near the stacking portions; these structures can also generate a large net flow theoretically in the direction opposite that of a previous prediction for a standard vortex flow. Furthermore, by solving the one-dimensional Poisson-Nernst-Plank (PNP) equations in the presence of ac electric fields, we find that the anomalous flow reversal occurs by the phase retardation between the induced diffuse charge and the tangential electric field. In addition, we successfully explain the nonlinearity of the flow velocity on the applied voltage by the PNP analysis. In the future, we expect to improve the pumping performance significantly by using stacking structures of conductive posts along with a low-cost process.

  6. Nanofiltration vs. reverse osmosis for the removal of emerging organic contaminants in water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-10-01

    Reverse osmosis (RO) in existing water reuse facilities is a water industry standard. However, that approach may be questioned taking into consideration that "tight" NF can be equal or "better" than RO. NF can achieve the same removals of RO membranes when dealing with emerging organic contaminants (pharmaceuticals, pesticides, endocrine disruptors and others). Experiments using 18 emerging contaminants were performed using membranes NF200 and NF90 at bench-scale units, and for a more complete study, results of NF and RO pilot and full-scale experiments where compared to our experimental results. The removal results showed that NF can remove many emerging contaminants. The average removal by tight NF was 82% for neutral contaminants and 97% for ionic contaminants. The average removal by RO was 85% for neutral contaminants and 99% for ionic contaminants. Aquifer recharge and recovery (ARR) followed by NF can effectively remove emerging contaminants with removals over 90% when loose NF membranes are used.

  7. Removal of bisphenol A (BPA) from water by various nanofiltration (NF) and reverse osmosis (RO) membranes.

    Science.gov (United States)

    Yüksel, Suna; Kabay, Nalan; Yüksel, Mithat

    2013-12-15

    The removal of an endocrine disrupting compound, bisphenol A (BPA), from model solutions by selected nanofiltration (NF) and reverse osmosis (RO) membranes was studied. The commercially available membranes NF 90, NF 270, XLE BWRO, BW 30 (Dow FilmTech), CE BWRO and AD SWRO (GE Osmonics) were used to compare their performances for BPA removal. The water permeability coefficients, rejection of BPA and permeate flux values were calculated for all membranes used. No significant changes in their BPA removal were observed for all tight polyamide based NF and RO membranes tested except for loose NF 270 membrane. The polyamide based membranes exhibited much better performance than cellulose acetate membrane for BPA removal. Almost a complete rejection (≥ 98%) for BPA was obtained with three polyamide based RO membranes (BW 30, XLE BWRO and AD SWRO). But cellulose acetate based CE BWRO membrane offered a low and variable (10-40%) rejection for BPA.

  8. Low-temperature distillation plants: a comparison with seawater reverse osmosis

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.

    1981-07-01

    Low-temperature distillation plants using large aluminum-alloy heat-transfer surfaces have reduced energy requirements to levels projected today for second-generation seawater reverse-osmosis (SWRO) plants. Less sensitive to feed contamination, and totally free from maintenance associated with a complex and critical feed-pretreatment system and periodic membrane replacements, the low-temperature distillation plants out-perform SWRO plants also by their higher-quality product, 2-10 ppM TDS versus 300 to 1000 ppM TDS. Energy requirements and operating costs for Low Temperature Vapor Compression (LT-VC) and Multi-Effect-Distillation (LT-MED) plants, in dual-purpose and various waste-heat-utilization schemes, are compared with those of SWRO plants. 10 references, 14 figures, 8 tables.

  9. Two-step optimization of pressure and recovery of reverse osmosis desalination process.

    Science.gov (United States)

    Liang, Shuang; Liu, Cui; Song, Lianfa

    2009-05-01

    Driving pressure and recovery are two primary design variables of a reverse osmosis process that largely determine the total cost of seawater and brackish water desalination. A two-step optimization procedure was developed in this paper to determine the values of driving pressure and recovery that minimize the total cost of RO desalination. It was demonstrated that the optimal net driving pressure is solely determined by the electricity price and the membrane price index, which is a lumped parameter to collectively reflect membrane price, resistance, and service time. On the other hand, the optimal recovery is determined by the electricity price, initial osmotic pressure, and costs for pretreatment of raw water and handling of retentate. Concise equations were derived for the optimal net driving pressure and recovery. The dependences of the optimal net driving pressure and recovery on the electricity price, membrane price, and costs for raw water pretreatment and retentate handling were discussed.

  10. Optimization of the Sequence of Washing Reverse Osmosis Membranes Used for Seawater Desalination

    Directory of Open Access Journals (Sweden)

    S. Gutierrez-Ruiz

    2017-04-01

    Full Text Available Seawater contains a number of organic and inorganic components that cause fouling of membranes when subjected to a process of reverse osmosis desalination. This fouling is one of the most important problems in the management of desalination plants, as it entails a significant loss in system performance. For membranes to be able to continue operating under appropriate conditions, they must undergo periodic cleaning protocols. This paper presents the results obtained when, subjecting a previously fouled aromatic polyamide membrane to different washing agents and using different concentrations of the same. Optimal concentrations of cleaning reagents were established. The results indicate that the performance of cleaning using a mixture of reagents, and alternating alkaline and acidic media, enabled maximum recovery of the membrane permeate flux (94.2 % and a significant reduction in the consumption of cleaning reagents.

  11. Evaluation of membrane bioreactor for advanced treatment of industrial wastewater and reverse osmosis pretreatment

    Science.gov (United States)

    2013-01-01

    The evaluation of a membrane bioreactor (MBR) for pretreatment of reverse osmosis (RO) in order to reuse and reclamation of industrial town wastewater treatment plant was investigated in this study. Performance of MBR effluent through water quality in term of parameters such as chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN) and total coliform (TC) were measured. Also Silt density index (SDI) was used as indicator for RO feed water. The results of this study demonstrated that MBR produce a high quality permeate water. Approximately 75%, 98%, 74% and 99.9% removal of COD, TSS, TN and TC were recorded, respectively. Also SDI of the permeate effluent from membrane was below 3 for most of the times. It means that pilot yield a high quality treated effluent from the membrane module which can be used as RO feed water. PMID:24355199

  12. Removal of fluoride and uranium by nanofiltration and reverse osmosis: a review.

    Science.gov (United States)

    Shen, Junjie; Schäfer, Andrea

    2014-12-01

    Inorganic contamination in drinking water, especially fluoride and uranium, has been recognized as a worldwide problem imposing a serious threat to human health. Among several treatment technologies applied for fluoride and uranium removal, nanofiltration (NF) and reverse osmosis (RO) have been studied extensively and proven to offer satisfactory results with high selectivity. In this review, a comprehensive summary and critical analysis of previous NF and RO applications on fluoride and uranium removal is presented. Fluoride retention is generally governed by size exclusion and charge interaction, while uranium retention is strongly affected by the speciation of uranium and size exclusion usually plays a predominant role for all species. Adsorption on the membrane occurs as some uranium species interact with membrane functional groups. The influence of operating conditions (pressure, crossflow velocity), water quality (concentration, solution pH), solute–solute interactions, membrane characteristics and membrane fouling on fluoride and uranium retention is critically reviewed.

  13. Dynamics of water and solute transport in polymeric reverse osmosis membranes via molecular dynamics simulations

    CERN Document Server

    Shen, Meng; Lueptow, Richard M

    2016-01-01

    The Angstrom-scale transport characteristics of water and six different solutes, methanol, ethanol, 2-propanol, urea, Na+, and Cl-, were studied for a polyamide reverse osmosis (RO) membrane, FT-30, using non-equilibrium molecular dynamics (NEMD) simulations. Results indicate that water transport increases with an increasing fraction of connected percolated free volume, or water-accessible open space, in the membrane polymer structure. This free volume is enhanced by the dynamic structure of the membrane at the molecular level as it swells when hydrated and vibrates due to molecular collisions allowing a continuous path connecting the opposite membrane surfaces. The tortuous paths available for transport of solutes result in Brownian motion of solute molecules and hopping from pore to pore as they pass through the polymer network structure of the membrane. The transport of alcohol solutes decreases for solutes with larger Van der Waals volume, which corresponds to less available percolated free volume, or sol...

  14. Reverse Osmosis Filter Use and High Arsenic Levels in Private Well Water

    Science.gov (United States)

    George, Christine M.; Smith, Allan H.; Kalman, David A.; Steinmaus, Craig M.

    2013-01-01

    Inorganic arsenic causes cancer, and millions of people worldwide are exposed to arsenic-contaminated water. Regulatory standards for arsenic levels in drinking water generally do not apply to private domestic wells. Reverse osmosis (RO) units commonly are used by well owners to reduce arsenic concentrations, but may not always be effective. In a survey of 102 homes in Nevada, 19 used RO devices. Pre- and post-RO filtration arsenic concentrations averaged 443 μg/l and 87 μg/l, respectively. The average absolute and percent reductions in arsenic concentrations after filtration were 356 μg/l and 79%, respectively. Postfiltration concentrations were higher than 10 μg/l in 10 homes and higher than 100 μg/l in 4 homes. These findings provide evidence that RO filters do not guarantee safe drinking water and, despite regulatory standards, some people continue to be exposed to very high arsenic concentrations. PMID:17867571

  15. Biological support media influence the bacterial biofouling community in reverse osmosis water reclamation demonstration plants.

    Science.gov (United States)

    Ferrera, Isabel; Mas, Jordi; Taberna, Elisenda; Sanz, Joan; Sánchez, Olga

    2015-01-01

    The diversity of the bacterial community developed in different stages of two reverse osmosis (RO) water reclamation demonstration plants designed in a wastewater treatment plant (WWTP) in Tarragona (Spain) was characterized by applying 454-pyrosequencing of the 16S rRNA gene. The plants were fed by secondary treated effluent to a conventional pretreatment train prior to the two-pass RO system. Plants differed in the material used in the filtration process, which was sand in one demonstration plant and Scandinavian schists in the second plant. The results showed the presence of a highly diverse and complex community in the biofilms, mainly composed of members of the Betaproteobacteria and Bacteroidetes in all stages, with the presence of some typical wastewater bacteria, suggesting a feed water origin. Community similarities analyses revealed that samples clustered according to filter type, highlighting the critical influence of the biological supporting medium in biofilm community structure.

  16. Evaluation of potential for reuse of industrial wastewater using metal-immobilized catalysts and reverse osmosis.

    Science.gov (United States)

    Choi, Jeongyun; Chung, Jinwook

    2015-04-01

    This report describes a novel technology of reusing the wastewater discharged from the display manufacturing industry through an advanced oxidation process (AOP) with a metal-immobilized catalyst and reverse osmosis (RO) in the pilot scale. The reclaimed water generated from the etching and cleaning processes in display manufacturing facilities was low-strength organic wastewater and was required to be recycled to secure a water source. For the reuse of reclaimed water to ultrapure water (UPW), a combination of solid-phase AOP and RO was implemented. The removal efficiency of TOC by solid-phase AOP and RO was 92%. Specifically, the optimal acid, pH, and H2O2 concentrations in the solid-phase AOP were determined. With regard to water quality and operating costs, the combination of solid-phase AOP and RO was superior to activated carbon/RO and ultraviolet AOP/anion polisher/coal carbon.

  17. Bacterial bioluminescence response to long-term exposure to reverse osmosis treated effluents from dye industries.

    Science.gov (United States)

    Ravindran, J; Manikandan, B; Shirodkar, P V; Francis, K X; Mani Murali, R; Vethamony, P

    2014-10-01

    The bacterial bioluminescence assay is one of the novel means for toxicity detection. The bioluminescence response of 2 marine bioluminescent bacteria was tested upon their long-term exposure to 9 different reverse osmosis (RO) rejects with varying chemical composition sampled from various dye industries. Bioluminescent bacteria were cultured in the RO reject samples, at different concentrations, and their growth rate and luminescence was measured for 24 h. The RO reject samples caused sublethal effects upon exposure and retarded the growth of bacteria, confirming their toxic nature. Further, continuation of the exposure showed that the initial luminescence, though reduced, recovered and increased beyond the control cultures irrespective of cell density, and finally decreased once again. The present study emphasizes the need of evolving a long-term exposure assay and shows that the method followed in this study is suitable to evaluate the toxicants that exert delayed toxicity, using lower concentrations of toxicants as well as coloured samples.

  18. Cleaning efficacy of hydroxypropyl-beta-cyclodextrin for biofouling reduction on reverse osmosis membranes.

    Science.gov (United States)

    Alayande, Abayomi Babatunde; Kim, Lan Hee; Kim, In S

    2016-01-01

    In this study, an environmentally friendly compound, hydroxypropyl-beta-cyclodextrin (HP-β-CD) was applied to clean reverse osmosis (RO) membranes fouled by microorganisms. The cleaning with HP-β-CD removed the biofilm and resulted in a flux recovery ratio (FRR) of 102%. As cleaning efficiency is sometimes difficult to determine using flux recovery data alone, attached bacterial cells and extracellular polymeric substances (EPS) were quantified after cleaning the biofouled membrane with HP-β-CD. Membrane surface characterization using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and atomic force microscopy (AFM) confirmed the effectiveness of HP-β-CD in removal of biofilm from the RO membrane surface. Finally, a comparative study was performed to investigate the competitiveness of HP-β-CD with other known cleaning agents such as sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA), Tween 20, rhamnolipid, nisin, and surfactin. In all cases, HP-β-CD was superior.

  19. Water permeability of nanoporous graphene at realistic pressures for reverse osmosis desalination

    Energy Technology Data Exchange (ETDEWEB)

    Cohen-Tanugi, David; Grossman, Jeffrey C. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-08-21

    Nanoporous graphene (NPG) shows tremendous promise as an ultra-permeable membrane for water desalination thanks to its atomic thickness and precise sieving properties. However, a significant gap exists in the literature between the ideal conditions assumed for NPG desalination and the physical environment inherent to reverse osmosis (RO) systems. In particular, the water permeability of NPG has been calculated previously based on very high pressures (1000–2000 bars). Does NPG maintain its ultrahigh water permeability under real-world RO pressures (<100 bars)? Here, we answer this question by drawing results from molecular dynamics simulations. Our results indicate that NPG maintains its ultrahigh permeability even at low pressures, allowing a permeate water flux of 6.0 l/h-bar per pore, or equivalently 1041 ± 20 l/m{sup 2}-h-bar assuming a nanopore density of 1.7 × 10{sup 13} cm{sup −2}.

  20. State of the reverse osmosis membrane of sea water corso plant desalination (Algiers)

    Science.gov (United States)

    Abdessemed, D.; Hamouni, S.; Nezzal, G.

    2009-11-01

    Seawater reverse osmosis (SWRO) desalination is being increasingly emphasized as a strategy for conservation of limited resources of freshwater. Although desalination has been developed for the last few decades, the SWRO operation is still affected by membrane fouling. The membrane fouling of SWRO has a significant impact on operation of desalination plants. We follow the evolution of the permeate conductivity during three months of the sea water Corso (Algiers) plant desalination. The purpose of this work is to conduct an autopsy of fouled membranes in seawater using the scanning electron microscopy (SEM) coupled by an analysis EDX. This membrane shows a change of the surface morphology, which justifies the abrupt increase in the conductivity of the permeate in May 2006. In order to identify the nature of the fouling deposit, we analysed this deposit by Xrays diffraction (XRD).

  1. Vanillin, a potential agent to prevent biofouling of reverse osmosis membrane.

    Science.gov (United States)

    Kappachery, Sajeesh; Paul, Diby; Yoon, Jeyong; Kweon, Ji Hyang

    2010-08-01

    Reverse osmosis (RO) membrane systems are widely used in water purification plants. Reduction in plant performance due to biofilm formation over the membrane is an inherent problem. As quorum sensing (QS) mechanisms of microorganisms have been reported to be involved in the formation of biofilm, ways are sought for quorum quenching (QQ) and thereby prevention of biofilm formation. In this study using a chemostat culture run for seven days in a CDC reactor it was found that a natural QQ compound, vanillin considerably suppressed bacterial biofilm formation on RO membrane. There was 97% reduction in biofilm surface coverage, when grown in the presence of vanillin. Similarly, the average thickness, total biomass and the total protein content of the biofilm that formed in the presence of vanillin were significantly less than that of the control. However vanillin had no effect on 1-day old pre-formed biofilm.

  2. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation

    DEFF Research Database (Denmark)

    Vingerhoeds, Monique H.; Nijenhuis-de Vries, Mariska A.; Ruepert, Nienke

    2016-01-01

    , permeate, and permeate with added minerals (40 or 120 mg Ca/L, added as CaCO3, and 4 or 24 mg Mg/L added as MgCl2), as well as commercially available bottled drinking waters, to span a relevant product space in which the remineralised samples could be compared. All samples were analysed with respect......Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from...... permeate. Both the nature and the concentrations of added minerals affect the taste of the water and in turn its acceptance by consumers. The aim of this study was to examine differences in taste between various remineralised drinking waters.Samples selected varied in mineral composition, i.e. tap water...

  3. Water permeability of nanoporous graphene at realistic pressures for reverse osmosis desalination

    Science.gov (United States)

    Cohen-Tanugi, David; Grossman, Jeffrey C.

    2014-08-01

    Nanoporous graphene (NPG) shows tremendous promise as an ultra-permeable membrane for water desalination thanks to its atomic thickness and precise sieving properties. However, a significant gap exists in the literature between the ideal conditions assumed for NPG desalination and the physical environment inherent to reverse osmosis (RO) systems. In particular, the water permeability of NPG has been calculated previously based on very high pressures (1000-2000 bars). Does NPG maintain its ultrahigh water permeability under real-world RO pressures (<100 bars)? Here, we answer this question by drawing results from molecular dynamics simulations. Our results indicate that NPG maintains its ultrahigh permeability even at low pressures, allowing a permeate water flux of 6.0 l/h-bar per pore, or equivalently 1041 ± 20 l/m2-h-bar assuming a nanopore density of 1.7 × 1013 cm-2.

  4. Desalination of Red Sea water using both electrodialysis and reverse osmosis as complementary methods

    Directory of Open Access Journals (Sweden)

    E.A. Abdel-Aal

    2015-03-01

    Full Text Available Desalination process separates nearly salt free water from sea or brackish water. So, desalination process is becoming a solution for water scarcity all over the world. Two membrane methods of water desalination namely electrodialysis (ED and reverse osmosis (RO are used in this study as complementary methods. The results show that both ED and RO can be used as integrated system. This system is economic and cost effective compared with each individual method provided using the ED system before the RO. In this study, it was approved that seawater can be used as it is an electrolyte. TDS of Red Sea water was decreased from 42070 ppm to 2177 ppm achieving 94.8% removal efficiency using ED for half of its optimum time. Total removal efficiency of 99.4% can be obtained using the combined system of ED and RO.

  5. Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

    Directory of Open Access Journals (Sweden)

    Irene Carrillo

    2011-01-01

    Full Text Available The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS, exposed to reverse osmosis water (RO used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP, potentiodynamic polarization (PP, and electrochemical impedance spectroscopy (EIS. The surface conditions were characterized by scanning electron microscopy (SEM and electron dispersive X-ray spectroscopy (EDS. The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

  6. Use of reverse osmosis membranes for the separation of lemongrass essential oil and supercritical CO2

    Directory of Open Access Journals (Sweden)

    L.A.V. Sarmento

    2004-06-01

    Full Text Available Although it is still used very little by industry, the process of essential oil extraction from vegetable matrices with supercritical CO2 is regarded as a potentially viable technique. The operation of separating the extract from the solvent is carried out by reducing the pressure in the system. Separation by membranes is an alternative that offers lower energy consumption and easier operation than traditional methods of separation. Combining the processes essential oil extraction with supercritical CO2 and separation by membranes permits the separation of solvent and oil without the need for large variations in extraction conditions. This results in a large energy savings in the case of solvent repressurisation and reuse. In this study, the effectiveness of reverse osmosis membranes in separating lemongrass essential oil from mixtures with supercritical CO2 was tested. The effects of feed oil concentration and transmembrane pressure on CO2 permeate flux and oil retention were studied for three membrane models.

  7. The effect of flow and chemical corrosion in reverse osmosis over desalinated water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jae [Chunnam National Univ., Gwangju (Korea, Republic of); Pak, Byung Gu [Doosan Heavy Industry Co., Tongyoung (Korea, Republic of)

    2015-12-15

    Desalinated water produced by a reverse osmosis (RO) filtering method forms about 22% of total production of desalinated water in the world. However, the RO environment is very corrosive due to the presence of various chemicals for water treatment and the flow of sand particles leading to corrosion. Recently, there has been much effort to substitute cheaper and more corrosion resistant stainless steels for copper based alloys as a valve material in RO. Nevertheless, the effects of chemicals and particles on the corrosion of stainless steels have rarely been studied. Erosion phenomenon was detected under the condition with the flow rate of more than 8ms{sup -1} in spite of the absence of sand particles. In seawater containing sand particles, the erosion in stainless steels was accelerated further.

  8. Effectiveness of Subsidies in Technology Adoption: A Case Study Involving Reverse Osmosis (RO Membrane Technology

    Directory of Open Access Journals (Sweden)

    Nur Laili

    2016-12-01

    Full Text Available Adoption of new technologies is a process that involves technological learning and penetration of new products into the market. Within the process of new technologies adoption, government usually intervened by providing incentives, in order to support the technology adoption to be succeed. This paper examines the effectiveness of incentives for the sustainability of reverse osmosis (RO membrane technology adoption. The study conducted through single case study on SWRO installation in Mandangin Island, East Java, Indonesia. Results of case study indentify the existence of government incentive in the form of direct subsidies to decrease the price of clean water. Although successful in reducing the price of water, but effectiveness of the subsidy on the sustainability of SWRO is still low, which is operates only 30% in a year. Further analysis shows that these subsidies actually be counter-productive to the sustainability of SWRO installation.

  9. Electrochemical treatment of iopromide under conditions of reverse osmosis concentrates--elucidation of the degradation pathway.

    Science.gov (United States)

    Lütke Eversloh, C; Henning, N; Schulz, M; Ternes, T A

    2014-01-01

    Application of reverse osmosis for the reuse of treated wastewater on the one hand offers a way to provide high quality effluent waters. On the other hand reverse osmosis concentrates exhibiting highly concentrated contaminants are produced simultaneously. Electrochemical treatment of those concentrates is regarded as one possible answer to the problem of their disposal into surface waters. Nevertheless, due to the diversity of direct and indirect degradation processes during electrolysis, special care has to be taken about the formation of toxic transformation products (TPs). In this study the electrochemical transformation of the X-ray contrast medium iopromide was investigated as a representative of biologically persistent compounds. For this purpose, anodic oxidation at boron doped diamond as well as cathodic reduction using a platinum electrode were considered. Kinetic analyses revealed a transformation of 100 μM iopromide with first order kinetic constants between 0.6 and 1.6 × 10(-4) s(-1) at the beginning and a subsequent increase of the reaction order due to the influence of secondary oxidants formed during electrolysis. Mineralization up to 96% was achieved after about 7.5 h. At shorter treatment times several oxidatively and reductively formed transformation products were detected, whereas deiodinated iopromide represented the major fraction. Nevertheless, the latter exhibited negligible toxicological relevance according to tests on vibrio fisheri. Additional experiments utilizing a divided cell setup enabled the elucidation of the transformation pathway, whereas emerging TPs could be identified by means of high resolution mass spectrometry and MS(n)-fragmentations. During electrolysis the iodine released from Iopromide was found to 90% as iodide and to 10% as iodate even in the open cell experiments, limiting the potential formation of toxic iodo-disinfection by-products. Chlorinated TPs were not found.

  10. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation.

    Science.gov (United States)

    Vingerhoeds, Monique H; Nijenhuis-de Vries, Mariska A; Ruepert, Nienke; van der Laan, Harmen; Bredie, Wender L P; Kremer, Stefanie

    2016-05-01

    Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from permeate. Both the nature and the concentrations of added minerals affect the taste of the water and in turn its acceptance by consumers. The aim of this study was to examine differences in taste between various remineralised drinking waters. Samples selected varied in mineral composition, i.e. tap water, permeate, and permeate with added minerals (40 or 120 mg Ca/L, added as CaCO3, and 4 or 24 mg Mg/L added as MgCl2), as well as commercially available bottled drinking waters, to span a relevant product space in which the remineralised samples could be compared. All samples were analysed with respect to their physical-chemical properties. Sensory profiling was done by descriptive analysis using a trained panel. Significant attributes included taste intensity, the tastes bitter, sweet, salt, metal, fresh and dry mouthfeel, bitter and metal aftertaste, and rough afterfeel. Total dissolved solids (TDS) was a major determinant of the taste perception of water. In general, lowering mineral content in drinking water in the range examined (from water from fresh towards bitter, dry, and rough sensations. In addition, perceived freshness of the waters correlated positively with calcium concentration. The greatest fresh taste was found for water with a TDS between 190 and 350 mg/L. Remineralisation of water after reverse osmosis can improve drinking quality significantly.

  11. Electrochemical oxidation of reverse osmosis concentrate on mixed metal oxide (MMO) titanium coated electrodes.

    Science.gov (United States)

    Bagastyo, Arseto Y; Radjenovic, Jelena; Mu, Yang; Rozendal, René A; Batstone, Damien J; Rabaey, Korneel

    2011-10-15

    Reverse osmosis (RO) membranes have been successfully applied around the world for wastewater reuse applications. However, RO is a physical separation process, and besides the clean water stream (permeate) a reverse osmosis concentrate (ROC) is produced, usually representing 15-25% of the feed water flow and containing the organic and inorganic contaminants at higher concentrations. In this study, electrochemical oxidation was investigated for the treatment of ROC generated during the reclamation of municipal wastewater effluent. Using laboratory-scale two-compartment electrochemical systems, five electrode materials (i.e. titanium coated with IrO2-Ta2O5, RuO2-IrO2, Pt-IrO2, PbO2, and SnO2-Sb) were tested as anodes in batch mode experiments, using ROC from an advanced water treatment plant. The best oxidation performance was observed for Ti/Pt-IrO2 anodes, followed by the Ti/SnO2-Sb and Ti/PbO2 anodes. The effectiveness of the treatment appears to correlate with the formation of oxidants such as active chlorine (i.e. Cl2/HClO/ClO-). As a result, electro-generated chlorine led to the abundant formation of harmful by-products such as trihalomethanes (THMs) and haloacetic acids (HAAs), particularly at Ti/SnO2-Sb and Ti/Pt-IrO2 anodes. The highest concentration of total HAAs (i.e. 2.7 mg L(-1)) was measured for the Ti/SnO2-Sb electrode, after 0.55 Ah L(-1) of supplied specific electrical charge. Irrespective of the used material, electrochemical oxidation of ROC needs to be complemented by a polishing treatment to alleviate the release of halogenated by-products. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Reverse osmosis, the solution for producing steam from highly saline water; Osmosis inversa, la solucion para la produccion de vapor con aguas de alta salinidad

    Energy Technology Data Exchange (ETDEWEB)

    Pujadas, A.

    2003-07-01

    Based on an exhaustive description of a particular example, the costs of installing an implementing various water treatment solutions for feeding a steam boiler are examined. When the characteristics of the water available indicate that it has a high saline content, i is possible to demonstrate the enormous technical, economic and environmental advantages of reducing its saline level by a system of reverse osmosis compared to the classical ion exchange resins. A list is given of the features to be taken into account in defining the equipment involved in treating the water for feeding steam boilers. (Author)

  13. Analysis of the Decline Rate of Reverse Osmosis Desalination%反渗透脱盐率下降问题分析

    Institute of Scientific and Technical Information of China (English)

    王少鹏; 李利娟

    2014-01-01

    Taking the working principle and application of reverse osmosis membrane areas as extension and on the base of the problem in the process of reverse osmosis in Henan Yuguang Co . LTD. the reverse osmosis desalting rate problem and analysis methods are discussed and the measure of abnormal avoid reverse osmosis system is put forward .%以反渗透膜的工作原理及应用领域作为引申,并结合河南豫光股份有限公司的反渗透运行过程中出现的情况,引出反渗透脱盐率下降问题的原因及分析方法,并提出避免反渗透系统异常的建议。

  14. Integrating tunable anion exchange with reverse osmosis for enhanced recovery during inland brackish water desalination.

    Science.gov (United States)

    Smith, Ryan C; SenGupta, Arup K

    2015-05-01

    For inland brackish water desalination by reverse osmosis or RO, concentrate or reject disposal poses a major challenge. However, enhanced recovery and consequent reduction in the reject volume using RO processes is limited by the solubility of ions present in the feedwater. One of the most common and stubborn precipitate formed during desalination is calcium sulfate. Reducing or eliminating the presence of sulfate would allow the process to operate at higher recoveries without threat to membrane scaling. In this research, this goal is accomplished by using an appropriate mixture of self-regenerating anion exchange resins that selectively remove and replace sulfate by chloride prior to the RO unit. Most importantly, the mixed bed of anion exchange resins is self-regenerated with the reject brine from the RO process, thus requiring no addition of external chemicals. The current work demonstrates the reversibility of the hybrid ion exchange and RO (HIX-RO) process with 80% recovery for a brackish water composition representative of groundwater in San Joaquin Valley in California containing approximately 5200 mg/L of total dissolved solids or TDS. Consequently, the reject volume can be reduced by 50% without the threat of sulfate scaling and use of antiscaling chemicals can be eliminated altogether. By appropriately designing or tuning the mixed bed of anion exchange resins, the process can be extended to nearly any composition of brackish water for enhanced recovery and consequent reduction in the reject volume.

  15. 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.

  16. Data on daily fluoride intake based on drinking water consumption prepared by household desalinators working by reverse osmosis process.

    Science.gov (United States)

    Karbasdehi, Vahid Noroozi; Dobaradaran, Sina; Esmaili, Abdolhamid; Mirahmadi, Roghayeh; Ghasemi, Fatemeh Faraji; Keshtkar, Mozhgan

    2016-09-01

    In this data article, we evaluated the daily fluoride contents in 20 household desalinators working by reverse osmosis (RO) process in Bushehr, Iran. The concentration levels of fluoride in inlet and outlet waters were determined by the standard SPADNS method using a spectrophotometer (M501 Single Beam Scanning UV/VIS, UK). The fluoride content in outlet waters were compared with EPA and WHO guidelines for drinking water.

  17. Waste treatment by reverse osmosis and membrane processing. (Latest citations from the NTIS bibliographic database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    The bibliography contains citations concerning the technology of reverse osmosis and membrane processing in sewage and industrial waste treatment. Citations discuss ultrafiltration, industrial water reuse, hazardous waste treatment, municipal wastes, and materials recovery. Waste reduction and recycling in electroplating, metal finishing, and circuit board manufacturing are considered. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  18. 反渗透预处理及膜清洗方法%Pretreatment and membrane cleaning of reverse osmosis

    Institute of Scientific and Technical Information of China (English)

    龚军军; 贾铭椿

    2000-01-01

    基于预处理和膜清洗对于反渗透RO(reverse osmosis)长期稳定运行的重要性,介绍了常规预处理方法及其改进、膜法预处理等预处理方法,以及各种新型的物理、化学膜清洗方法.

  19. A new class of draw solutions for minimizing reverse salt flux to improve forward osmosis desalination.

    Science.gov (United States)

    Nguyen, Hau Thi; Nguyen, Nguyen Cong; Chen, Shiao-Shing; Ngo, Huu Hao; Guo, Wenshan; Li, Chi-Wang

    2015-12-15

    The applications of forward osmosis (FO) have been hindered because of the lack of an optimal draw solution. The reverse salt flux from the draw solution not only reduces the water flux but also increases the cost of draw solute replenishment. Therefore, in this study, Tergitol NP7 and NP9 with a long straight carbon chain and low critical micelle concentration (CMC) were coupled with highly charged ethylenediaminetetraacetic acid (EDTA) as an innovative draw solution to minimize reverse salt diffusion in FO for the first time. The results showed that the lowest reverse salt flux of 0.067 GMH was observed when 0.1M EDTA-2Na coupled with 15mM NP7 was used as a draw solution and deionized water was used as a feed solution in FO mode (active layer facing with the feed solution). This is due to the hydrophobic interaction between the tails of NP7 and the FO membrane, thus creating layers on the membrane surface and constricting the FO membrane pores. Moreover, 1M EDTA-2Na coupled with 15mM NP7 is promising as an optimal draw solution for brackish water and sea water desalination. Average water fluxes of 7.68, 6.78, and 5.95 LMH were achieved when brackish water was used as a feed solution (5, 10, and 20g/L NaCl), and an average water flux of 3.81 LMH was achieved when sea water was used as a feed solution (35g/L NaCl). The diluted draw solution was recovered using a nanofiltration (NF-TS80) membrane with a high efficiency of 95% because of the high charge and large size of the draw solution.

  20. Evaluation of multivariate statistical analyses for monitoring and prediction of processes in an seawater reverse osmosis desalination plant

    Energy Technology Data Exchange (ETDEWEB)

    Kolluri, Srinivas Sahan; Esfahani, Iman Janghorban; Garikiparthy, Prithvi Sai Nadh; Yoo, Chang Kyoo [Kyung Hee University, Yongin (Korea, Republic of)

    2015-08-15

    Our aim was to analyze, monitor, and predict the outcomes of processes in a full-scale seawater reverse osmosis (SWRO) desalination plant using multivariate statistical techniques. Multivariate analysis of variance (MANOVA) was used to investigate the performance and efficiencies of two SWRO processes, namely, pore controllable fiber filterreverse osmosis (PCF-SWRO) and sand filtration-ultra filtration-reverse osmosis (SF-UF-SWRO). Principal component analysis (PCA) was applied to monitor the two SWRO processes. PCA monitoring revealed that the SF-UF-SWRO process could be analyzed reliably with a low number of outliers and disturbances. Partial least squares (PLS) analysis was then conducted to predict which of the seven input parameters of feed flow rate, PCF/SF-UF filtrate flow rate, temperature of feed water, turbidity feed, pH, reverse osmosis (RO)flow rate, and pressure had a significant effect on the outcome variables of permeate flow rate and concentration. Root mean squared errors (RMSEs) of the PLS models for permeate flow rates were 31.5 and 28.6 for the PCF-SWRO process and SF-UF-SWRO process, respectively, while RMSEs of permeate concentrations were 350.44 and 289.4, respectively. These results indicate that the SF-UF-SWRO process can be modeled more accurately than the PCF-SWRO process, because the RMSE values of permeate flowrate and concentration obtained using a PLS regression model of the SF-UF-SWRO process were lower than those obtained for the PCF-SWRO process.

  1. Use of water processed by reverse osmosis For vapor generation in tobacco industry

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Klimeck Gouvea

    2012-06-01

    Full Text Available This article presents a study due to the technical use of reverse osmosis to treat the boiler water for steam generation in a plant of tobacco processing in Santa Catarina, Brazil. The monitoring was conducted between the years 2006 to 2008, presenting the results concerning the improvement of water quality with emphasis on environmental and financial gains. Water quality can be observed by the reduction of 90% in silica content and 100% hardness, leading to a reduction of incrustation and corrosion of the system. Moreover, a reduction in the discharges water from the boiler volume reduced the water consumption by approximately 6,000 m3/year and also the consumption of chemicals used in wastewater treatment plant, with a reduction of 32.76 m3/day of effluents to treatment. The reducing of energy with natural gas for water heating replacement was almost 900,000 m3/year (19.45%, because of increased in heat exchange efficiency. The reducing in the CO2 emissions was in order of 1215,65 t/year. Finally, based on the achieved results obtained, can be possible to assume a reducing costs of production as a whole.

  2. Vacancy profile in reverse osmosis membranes studied by positron annihilation lifetime measurements and molecular dynamics simulations

    Science.gov (United States)

    Shimazu, A.; Goto, H.; Shintani, T.; Hirose, M.; Suzuki, R.; Kobayashi, Y.

    2013-06-01

    The positron annihilation technique using a slow positron beam can be used for the study of the vacancy profiles in typical reverse osmosis (RO) membranes. In this study, the vacancy profile in the polyamide membrane that exhibits a high permselectivity between ions and water was studied using the positron annihilation technique and molecular dynamics simulations. Ortho-positronium (o-Ps) lifetimes in the surface region of the membranes were evaluated by using a slow positron beam. The diffusion behavior of Na+ and water in the polyamides was simulated by molecular dynamics (MD) methods using the TSUBAME2 supercomputer at the Tokyo Institute of Technology and discussed with the vacancy profile probed by the o-Ps. The results suggested that the large hydration size of Na+ compared to the vacancy size in the polyamides contributes to the increased diffusivity selectivity of water/Na+ that is related to the NaCl desalination performance of the membrane. Both the hydration size of the ions and the vacancy size appeared to be significant parameters to discuss the diffusivity selectivity of water/ions in typical polyamide membranes.

  3. Solute transport model for trace organic neutral and charged compounds through nanofiltration and reverse osmosis membranes.

    Science.gov (United States)

    Kim, Tae-Uk; Drewes, Jörg E; Scott Summers, R; Amy, Gary L

    2007-09-01

    Rejection of trace organic compounds, including disinfection by-products (DBPs) and pharmaceutical active compounds (PhACs), by high-pressure membranes has become a focus of public interest internationally in both drinking water treatment and wastewater reclamation/reuse. The ability to simulate, or even predict, the rejection of these compounds by high-pressure membranes, encompassing nanofiltration (NF) and reverse osmosis (RO), will improve process economics and expand membrane applications. The objective of this research is to develop a membrane transport model to account for diffusive and convective contributions to solute transport and rejection. After completion of cross-flow tests and diffusion cell tests with target compounds, modeling efforts were performed in accordance with a non-equilibrium thermodynamic transport equation. Comparing the percentages of convection and diffusion contributions to transport, convection is dominant for most compounds, but diffusion is important for more hydrophobic non-polar compounds. Convection is also more dominant for looser membranes (i.e., NF). In addition, higher initial compound concentrations and greater J(0)/k ratios contribute to solute fluxes more dominated by convection. Given the treatment objective of compound rejection, compound transport and rejection trends are inversely related.

  4. Adsorption of phosphonate antiscalant from reverse osmosis membrane concentrate onto granular ferric hydroxide.

    Science.gov (United States)

    Boels, Luciaan; Keesman, Karel J; Witkamp, Geert-Jan

    2012-09-04

    Adsorptive removal of antiscalants offers a promising way to improve current reverse osmosis (RO) concentrate treatment processes and enables the reuse of the antiscalant in the RO desalination process. This work investigates the adsorption and desorption of the phosphonate antiscalant nitrilotris(methylenephosphonic acid) (NTMP) from RO membrane concentrate onto granular ferric hydroxide (GFH), a material that consists predominantly of akaganéite. The kinetics of the adsorption of NTMP onto GFH was predicted fairly well with two models that consider either combined film-pore or combined film-surface diffusion as the main mechanism for mass transport. It is also demonstrated that NTMP is preferentially adsorbed over sulfate by GFH at pH 7.85. The presence of calcium causes a transformation in the equilibrium adsorption isotherm from a Langmuir type to a Freundlich type with much higher adsorption capacities. Furthermore, calcium also increases the rate of adsorption substantially. GFH is reusable after regeneration with sodium hydroxide solution, indicating that NTMP can be potentially recovered from the RO concentrate. This work shows that GFH is a promising adsorbent for the removal and recovery of NTMP antiscalant from RO membrane concentrates.

  5. Subsurface intakes for seawater reverse osmosis facilities: Capacity limitation, water quality improvement, and economics

    KAUST Repository

    Missimer, Thomas M.

    2013-08-01

    The use of subsurface intake systems for seawater reverse osmosis (SWRO) desalination plants significantly improves raw water quality, reduces chemical usage and environmental impacts, decreases the carbon footprint, and reduces cost of treated water to consumers. These intakes include wells (vertical, angle, and radial type) and galleries, which can be located either on the beach or in the seabed. Subsurface intakes act both as intakes and as part of the pretreatment system by providing filtration and active biological treatment of the raw seawater. Recent investigations of the improvement in water quality made by subsurface intakes show lowering of the silt density index by 75 to 90%, removal of nearly all algae, removal of over 90% 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 subsurface intake systems. Although capital costs can be slightly to significantly higher compared to open-ocean intake system costs, a preliminary life-cycle cost analysis shows significant cost saving over operating periods of 10 to 30. years. © 2013 Elsevier B.V.

  6. Pseudomonas-related populations associated with reverse osmosis in drinking water treatment.

    Science.gov (United States)

    Sala-Comorera, Laura; Blanch, Anicet R; Vilaró, Carles; Galofré, Belén; García-Aljaro, Cristina

    2016-11-01

    Reverse osmosis membrane filtration technology (RO) is used to treat drinking water. After RO treatment, bacterial growth is still observed in water. However, it is not clear whether those microorganisms belong to species that can pose a health risk, such as Pseudomonas spp. The goal of this study is to characterize the bacterial isolates from a medium that is selective for Pseudomonas and Aeromonas which were present in the water fraction before and after the RO. To this end, isolates were recovered over two years and were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. They were then biochemically phenotyped and the population similarity indexes were calculated. The isolates were analysed for their capacity to form biofilms in vitro and antimicrobial susceptibility. There were significant differences between the microbial populations in water before and after RO. Furthermore, the structures of the populations analysed at the same sampling point were similar in different sampling campaigns. Some of the isolates had the capacity to form a biofilm and showed resistance to different antibiotics. A successful level filtration via RO and subsequent recolonization of the membrane with different species from those in the feed water was found. Pseudomonas aeruginosa was not recovered from among the isolates. This study increases the knowledge on the microorganisms present in water after RO treatment, with focus in one of the genus causing problems in RO systems associated with human health risk, Pseudomonas.

  7. Effect of water matrices on removal of veterinary pharmaceuticals by nanofiltration and reverse osmosis membranes

    Institute of Scientific and Technical Information of China (English)

    Davor Dolar; Arna Vukovi(c); Danijela A(a)perger; Kre(s)imir Ko(s)ulti(c)

    2011-01-01

    This study explored the removal of five veterinary pharmaceuticals (VPs) (sulfamethoxazole (SMETOX),trimethopfim (TMP),ciprofloxacin (CIPRO),dexamethasone (DEXA) and febantel (FEBA)) from different water matrices (Milli-Q water,model water,tap water and real pharmaceutical wastewater using four types of nanofiltration (NF) membranes (NF90,NF270,NF and HL) and two reverse osmosis (RO) membranes (LFC-1 and XLE).All VPs were added to different water matrices at a concentration of 10 mg/L.Rejections of VPs and water flux were measured.The rejection increased with increase of molecular weight.The highest rejections were obtained with RO membranes (LFC-1,XLE) and tight NF (NF90) membrane.In general,the rejection of VPs was higher in model water and tap water than in Milli-Q water,but the water flux was lower.This was mainly explained by ion adsorption inside the membranes pores.Narrower pore size counteracted the effect of presence of low concentration of natural organic matter (NOM) in tap water.The NOM was assumed to enhance the adsorption of VPs onto membrane surface,increased the size exclusion and electrostatic repulsion also appeared during the transport.Investigated water matrices had influence on water flux decline due to their complexity.

  8. Composition and Variability of Biofouling Organisms in Seawater Reverse Osmosis Desalination Plants ▿ †

    Science.gov (United States)

    Zhang, Minglu; Jiang, Sunny; Tanuwidjaja, Dian; Voutchkov, Nikolay; Hoek, Eric M. V.; Cai, Baoli

    2011-01-01

    Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Cellulophaga based on 16S rRNA gene sequencing analysis. The 16S rRNA gene clone library of the SWRO membrane biofilm showed that a filamentous bacterium, Leucothrix mucor, which belongs to the gammaproteobacteria, accounted for nearly 30% of the clone library, while the rest of the microorganisms (61.2% of the total clones) were related to the alphaproteobacteria. 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that bacteria colonizing the SWRO membrane represented a subportion of microbes in the source seawater; however, they were quite different from those colonizing the cartridge filter. The examination of five SWRO membranes from desalination plants located in different parts of the world showed that although the bacterial communities from the membranes were not identical to each other, some dominant bacteria were commonly observed. In contrast, bacterial communities in source seawater were significantly different based on location and season. Microbial profiles from 14 cartridge filters collected from different plants also revealed spatial trends. PMID:21551282

  9. Dynamic bacterial communities on reverse-osmosis membranes in a full-scale desalination plant.

    Science.gov (United States)

    Manes, C-L de O; West, N; Rapenne, S; Lebaron, P

    2011-01-01

    To better understand biofouling of seawater reverse osmosis (SWRO) membranes, bacterial diversity was characterized in the intake water, in subsequently pretreated water and on SWRO membranes from a full-scale desalination plant (FSDP) during a 9 month period. 16S rRNA gene fingerprinting and sequencing revealed that bacterial communities in the water samples and on the SWRO membranes were very different. For the different sampling dates, the bacterial diversity of the active and the total bacterial fractions of the water samples remained relatively stable over the sampling period whereas the bacterial community structure on the four SWRO membrane samples was significantly different. The richness and evenness of the SWRO membrane bacterial communities increased with usage time with an increase in the Shannon diversity index of 2.2 to 3.7. In the oldest SWRO membrane (330 days), no single operational taxonomic unit (OTU) dominated and the majority of the OTUs fell into the Alphaproteobacteria or the Planctomycetes. In striking contrast, a Betaproteobacteria OTU affiliated to the genus Ideonella was dominant and exclusively found in the membrane used for the shortest time (10 days). This suggests that bacteria belonging to this genus could be one of the primary colonizers of the SWRO membrane. Knowledge of the dominant bacterial species on SWRO membranes and their dynamics should help guide culture studies for physiological characterization of biofilm forming species.

  10. Composition and variability of biofouling organisms in seawater reverse osmosis desalination plants.

    Science.gov (United States)

    Zhang, Minglu; Jiang, Sunny; Tanuwidjaja, Dian; Voutchkov, Nikolay; Hoek, Eric M V; Cai, Baoli

    2011-07-01

    Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Cellulophaga based on 16S rRNA gene sequencing analysis. The 16S rRNA gene clone library of the SWRO membrane biofilm showed that a filamentous bacterium, Leucothrix mucor, which belongs to the gammaproteobacteria, accounted for nearly 30% of the clone library, while the rest of the microorganisms (61.2% of the total clones) were related to the alphaproteobacteria. 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that bacteria colonizing the SWRO membrane represented a subportion of microbes in the source seawater; however, they were quite different from those colonizing the cartridge filter. The examination of five SWRO membranes from desalination plants located in different parts of the world showed that although the bacterial communities from the membranes were not identical to each other, some dominant bacteria were commonly observed. In contrast, bacterial communities in source seawater were significantly different based on location and season. Microbial profiles from 14 cartridge filters collected from different plants also revealed spatial trends.

  11. Comparative pyrosequencing analysis of bacterial community change in biofilm formed on seawater reverse osmosis membrane.

    Science.gov (United States)

    Kim, In S; Lee, Jinwook; Kima, Sung-Jo; Yu, Hye-Weon; Jang, Am

    2014-01-01

    The change in bacterial community structure induced by bacterial competition and succession was investigated during seawater reverse osmosis (SWRO) in order to elucidate a possible link between the bacterial consortium on SWRO membranes and biofouling. To date, there has been no definitive characterization of the microbial diversity in SWRO in terms of distinguishing time-dependent changes in the richness or abundance of bacterial species. For bacterial succession within biofilms on the membrane surface, SWRO using a cross-flow filtration membrane test unit was operated for 5 and 100h, respectively. As results of the pyrosequencing analysis, bacterial communities differed considerably among seawater and the 5 and 100 h samples. From a total of 33,876 pyrosequences (using a 95% sequence similarity), there were less than 1% of shared species, confirming the influence of the operational time factor and lack of similarity of these communities. During SWRO operation, the abundance of Pseudomonas stutzeri BBSPN3 (GU594474) belonging to gamma-Proteobacteria suggest that biofouling of SWRO membrane might be driven by the dominant influence of a specific species. In addition, among the bacterial competition of five bacterial species (Pseudomonas aeruginosa, Bacillus sp., Rhodobacter sp., Flavobacterium sp., and Mycobacterium sp.) competing for bacterial colonization on the SWRO membrane surfaces, it was exhibited that Bacillus sp. was the most dominant. The dominant influences ofPseudomonas sp. and Bacillus sp. on biofouling during actual SWRO is decisive depending on higher removal efficiency of the seawater pretreatment.

  12. Changes in physicochemical and transport properties of a reverse osmosis membrane exposed to chloraminated seawater

    KAUST Repository

    Valentino, Lauren

    2015-02-17

    This study contributed to improving our understanding of how disinfectants, applied to control biofouling of reverse osmosis (RO) membranes, result in membrane performance degradation. We investigated changes in physicochemical properties and permeation performance of a RO membrane with fully aromatic polyamide (PA) active layer. Membrane samples were exposed to varying concentrations of monochloramine, bromide, and iodide in both synthetic and natural seawater. Elemental analysis of the membrane active layer by Rutherford backscattering spectrometry (RBS) revealed the incorporation of bromine and iodine into the polyamide. The kinetics of polyamide bromination were first order with respect to the concentration of the secondary oxidizing agent Br2 for the conditions investigated. Halogenated membranes were characterized after treatment with a reducing agent and heavy ion probes to reveal the occurrence of irreversible ring halogenation and an increase in carboxylic groups, the latter produced as a result of amide bond cleavage. Finally, permeation experiments revealed increases in both water permeability and salt passage as a result of oxidative damage.

  13. Reverse osmosis concentrate treatment by chemical oxidation and moving bed biofilm processes.

    Science.gov (United States)

    Vendramel, S M R; Justo, A; González, O; Sans, C; Esplugas, S

    2013-01-01

    In the present work, four oxidation techniques were investigated (O3, O3/UV, H2O2/O3, O3/H2O2/UV) to pre-treat reverse osmosis (RO) concentrate before treatment in a moving-bed biofilm reactor (MBBR) system. Without previous oxidation, the MBBR was able to remove a small fraction of the chemical oxygen demand (COD) (5-20%) and dissolved organic carbon (DOC) (2-15%). When the concentrate was previously submitted to oxidation, DOC removal efficiencies in the MBBR increased to 40-55%. All the tested oxidation techniques improved concentrate biodegradability. The concentrate treated by the combined process (oxidation and MBBR) presented residual DOC and COD in the ranges of 6-12 and 25-41 mg L(-1), respectively. Nitrification of the RO concentrate, pre-treated by oxidation, was observed in the MBBR. Ammonium removal was comprised between 54 and 79%. The results indicate that the MBBR was effective for the treatment of the RO concentrate, previously submitted to oxidation, generating water with an improved quality.

  14. Performance evaluation of reverse osmosis technology for selected antibiotics removal from synthetic pharmaceutical wastewater

    Directory of Open Access Journals (Sweden)

    Gholami Mitra

    2012-12-01

    Full Text Available Abstract This study addresses the possibility for low pressure reverse osmosis membrane (RE 2521, CSM process to serve as an alternative to remove selected antibiotics (ampicillin and amoxicillin from synthetic wastewater by changing operating conditions such as pH = 3, 6.5 and 10; Pressure = 9, 11 and13 (bar; antibiotic concentration = 10, 255 and 500(mg/L, and temperature = 20, 30 and 40°C. The experiment was designed based on Box-benken, which is a Response Surface methodology design (RSM, using Design Expert software. The concentration of antibiotics was measured by applying a UV-spectrophotometer (Cecil, at the wavelength of 254 nm. Results showed a range of rejection percentage from 73.52% to 99.36% and 75.1% to 98.8%, for amoxicillin and ampicillin, respectively. Considering the solute rejections and the membrane porosity show that the prevailing rejection mechanism of the examined antibiotics by the membrane was the size exclusion effect. The permeate flux for both of the antibiotics was 12–18.73 L/m2.h. Although the permeate flux and antibiotic rejection are influenced by operating pressure, pH, and temperature individually, the interaction between operating parameters did not have noticeable effects. According to the results obtained in this study, the application of RO membrane is recommended for the selected antibiotics to be removed to a considerable degree (up to 95%.

  15. Integrated Wireless Monitoring and Control System in Reverse Osmosis Membrane Desalination Plants

    Directory of Open Access Journals (Sweden)

    Al Haji Ahmad

    2015-01-01

    Full Text Available The operational processes of the Reverse Osmosis (RO membrane desalination plants require continuous monitoring through the constant attendance of operators to ensure proper productivity and minimize downtime and prevent membrane failure. Therefore, the plant must be equipped with a control system that monitors and controls the operational variables. Monitoring and controlling the affecting parameters are critical to the evaluation of the performance of the desalination plant, which will help the operator find and resolve problems immediately. Therefore, this paper was aimed at developing an RO unit by utilizing a wireless sensor network (WSN system. Hence, an RO pilot plant with a feed capacity of 1.2 m3/h was utilized, commissioned, and tested in Kuwait to assess and verify the performance of the integrated WSN in RO membrane desalination system. The investigated system allowed the operators to remotely monitor the operational process of the RO system. The operational data were smoothly recorded and monitored. Furthermore, the technical problems were immediately determined, which reduced the time and effort in rectifying the technical problems relevant to the RO performance. The manpower requirements of such treatment system were dramatically reduced by about 50%. Based on a comparison between manual and wireless monitoring operational processes, the availability of the integrated RO unit with a wireless monitoring was increased by 10%

  16. 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.

  17. 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.

  18. DRINKING WATER FROM DESALINATION OF SEAWATER: OPTIMIZATION OF REVERSE OSMOSIS SYSTEM OPERATING PARAMETERS

    Directory of Open Access Journals (Sweden)

    MARWAN M. SHAMEL

    2006-12-01

    Full Text Available This paper reports on the use of pilot scale membrane separation system coupled with another pilot scale plate heat exchanger to investigate the possibilities of sweetening seawater from Telok Kalong Beach, Terengganu, Malaysia. Reverse osmosis (RO membrane of a surface area of 0.5 m2 was used during the experimental runs. Experiments were conducted at different transmembrane pressures (TMP ranged from 40 to 55 bars, operation temperature ranged from 35 to 45oC, feed concentration (TDS ranged from 34900 to 52500 ppm and cross flow velocities ranged from 1.4 to 2.1 m/s. The result show that the flux values increased linearly with TMP as well as sodium ion rejection. Permeate flux values increased proportionally with the temperature and the later effect was more significant at high pressures. The temperature changing has also influenced the rejection of sodium ion. The minerals content especially NaCl and total dissolved solid (TDS in the drinking water produced in this research are conforming to the standards of World Health Organization (WHO.

  19. Multi-Response Optimization of Process Parameters for Imidacloprid Removal by Reverse Osmosis Using Taguchi Design.

    Science.gov (United States)

    Genç, Nevim; Doğan, Esra Can; Narcı, Ali Oğuzhan; Bican, Emine

    2017-05-01

      In this study, a multi-response optimization method using Taguchi's robust design approach is proposed for imidacloprid removal by reverse osmosis. Tests were conducted with different membrane type (BW30, LFC-3, CPA-3), transmembrane pressure (TMP = 20, 25, 30 bar), volume reduction factor (VRF = 2, 3, 4), and pH (3, 7, 11). Quality and quantity of permeate are optimized with the multi-response characteristics of the total dissolved solid (TDS), conductivity, imidacloprid, and total organic carbon (TOC) rejection ratios and flux of permeate. The optimized conditions were determined as membrane type of BW30, TMP 30 bar, VRF 3, and pH 11. Under these conditions, TDS, conductivity, imidacloprid, and TOC rejections and permeate flux were 97.50 97.41, 97.80, 98.00% and 30.60 L/m2·h, respectively. Membrane type was obtained as the most effective factor; its contribution is 64%. The difference between the predicted and observed value of multi-response signal/noise (MRSN) is within the confidence interval.

  20. Reverse osmosis integrity monitoring in water reuse: The challenge to verify virus removal - A review.

    Science.gov (United States)

    Pype, Marie-Laure; Lawrence, Michael G; Keller, Jurg; Gernjak, Wolfgang

    2016-07-01

    A reverse osmosis (RO) process is often included in the treatment train to produce high quality reuse water from treated effluent for potable purposes because of its high removal efficiency for salinity and many inorganic and organic contaminants, and importantly, it also provides an excellent barrier for pathogens. In order to ensure the continued protection of public health from pathogen contamination, monitoring RO process integrity is necessary. Due to their small sizes, viruses are the most difficult class of pathogens to be removed in physical separation processes and therefore often considered the most challenging pathogen to monitor. To-date, there is a gap between the current log credit assigned to this process (determined by integrity testing approved by regulators) and its actual log removal capability as proven in a variety of laboratory and pilot studies. Hence, there is a challenge to establish a methodology that more closely links to the theoretical performance. In this review, after introducing the notion of risk management in water reuse, we provide an overview of existing and potentially new RO integrity monitoring techniques, highlight their strengths and drawbacks, and debate their applicability to full-scale treatment plants, which open to future research opportunities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Biofilm Formation on Reverse Osmosis Membranes Is Initiated and Dominated by Sphingomonas spp.▿ †

    Science.gov (United States)

    Bereschenko, L. A.; Stams, A. J. M.; Euverink, G. J. W.; van Loosdrecht, M. C. M.

    2010-01-01

    The initial formation and spatiotemporal development of microbial biofilm layers on surfaces of new and clean reverse osmosis (RO) membranes and feed-side spacers were monitored in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The feed water of the RO system had been treated by the sequential application of coagulation, flocculation, sand filtration, ultrafiltration, and cartridge filtration processes. The design of the flow cells permitted the production of permeate under cross-flow conditions similar to those in spiral-wound RO membrane elements of the full-scale system. Membrane autopsies were done after 4, 8, 16, and 32 days of flow-cell operation. A combination of molecular (fluorescence in situ hybridization [FISH], denaturing gradient gel electrophoresis [DGGE], and cloning) and microscopic (field emission scanning electron, epifluorescence, and confocal laser scanning microscopy) techniques was applied to analyze the abundance, composition, architecture, and three-dimensional structure of biofilm communities. The results of the study point out the unique role of Sphingomonas spp. in the initial formation and subsequent maturation of biofilms on the RO membrane and feed-side spacer surfaces. PMID:20190090

  2. Reverse osmosis desalination of chitosan cross-linked graphene oxide/titania hybrid lamellar membranes

    Science.gov (United States)

    Deng, Hui; Sun, Penzhan; Zhang, Yingjiu; Zhu, Hongwei

    2016-07-01

    With excellent mass transport properties, graphene oxide (GO)-based lamellar membranes are believed to have great potential in water desalination. In order to quantify whether GO-based membranes are indeed suitable for reverse osmosis (RO) desalination, three sub-micrometer thick GO-based lamellar membranes: GO-only, reduced GO (RGO)/titania (TO) nanosheets and RGO/TO/chitosan (CTS) are prepared, and their RO desalination performances are evaluated in a home-made RO test apparatus. The photoreduction of GO by TO improves the salt rejection, which increases slowly with the membrane thickness. The RGO/TO/CTS hybrid membranes exhibit higher rejection rates of only about 30% (greater than threefold improvement compared with a GO-only membrane) which is still inferior compared to other commercial RO membranes. The low rejection rates mainly arise from the pressure-induced weakening of the ion-GO interlayer interactions. Despite the advantages of simple, low-cost preparation, high permeability and selectivity of GO-based lamellar membranes, as the current desalination performances are not high enough to afford practical application, there still remains a great challenge to realize high performance separation membranes for water desalination applications.

  3. Changes in physicochemical and transport properties of a reverse osmosis membrane exposed to chloraminated seawater.

    Science.gov (United States)

    Valentino, Lauren; Renkens, Tennie; Maugin, Thomas; Croué, Jean-Philippe; Mariñas, Benito J

    2015-02-17

    This study contributed to improving our understanding of how disinfectants, applied to control biofouling of reverse osmosis (RO) membranes, result in membrane performance degradation. We investigated changes in physicochemical properties and permeation performance of a RO membrane with fully aromatic polyamide (PA) active layer. Membrane samples were exposed to varying concentrations of monochloramine, bromide, and iodide in both synthetic and natural seawater. Elemental analysis of the membrane active layer by Rutherford backscattering spectrometry (RBS) revealed the incorporation of bromine and iodine into the polyamide. The kinetics of polyamide bromination were first order with respect to the concentration of the secondary oxidizing agent Br2 for the conditions investigated. Halogenated membranes were characterized after treatment with a reducing agent and heavy ion probes to reveal the occurrence of irreversible ring halogenation and an increase in carboxylic groups, the latter produced as a result of amide bond cleavage. Finally, permeation experiments revealed increases in both water permeability and salt passage as a result of oxidative damage.

  4. Performance Evaluation of Reverse Osmosis Technology for Selected Antibiotics Removal from Synthetic Pharmaceutical Wastewater

    Directory of Open Access Journals (Sweden)

    Mitra Gholami

    2012-12-01

    Full Text Available This study addresses the possibility for low pressure reverse osmosis membrane (RE 2521, CSM process to serve as an alternative to remove selected antibiotics (ampicillin and amoxicillin from synthetic wastewater by changing operating conditions such as pH = 3, 6.5 and 10; Pressure = 9, 11 and13 (bar; antibiotic concentration = 10, 255and 500(mg/L, and temperature = 20, 30 and 40°C. The experiment was designed based on Box-benken, which is a Response Surface methodology design (RSM, using Design Expert software. The concentration of antibiotics was measured by applying a UV-spectrophotometer (Cecil, at the wavelength of 254 nm. Results showed a range ofrejection percentage from 73.52% to 99.36% and 75.1% to 98.8%, for amoxicillin and ampicillin, respectively.Considering the solute rejections and the membrane porosity show that the prevailing rejection mechanism of the examined antibiotics by the membrane was the size exclusion effect. The permeate flux for both of the antibiotics was 12–18.73 L/m2.h. Although the permeate flux and antibiotic rejection are influenced by operating pressure, pH,and temperature individually, the interaction between operating parameters did not have noticeable effects. According to the results obtained in this study, the application of RO membrane is recommended for the selected antibiotics to be removed to a considerable degree (up to 95%.

  5. Effects of feed solution chemistry on low pressure reverse osmosis filtration of cesium and strontium.

    Science.gov (United States)

    Ding, Shiyuan; Yang, Yu; Huang, Haiou; Liu, Hengchen; Hou, Li-an

    2015-08-30

    The objective of this study was to identify the removal mechanisms of radionuclides by reverse osmosis (RO) membranes under conditions relevant to full-scale water treatment. For this purpose, the effects of feed solution chemistry on the removal of Cs and Sr by a low pressure RO system was investigated by systematically varying membrane surface charge, ionic composition, and organic matter concentrations. The results showed that the effects of solution chemistry on the filtration of Cs and Sr were related to their hydrated ionic radius, resulting in the predominance of the Donnan's effect and electrostatic interactions, respectively. Consequently, the rejection of Cs increased more pronouncedly than Sr with the increases of feed concentration. Due to the Donnan's effect, different anions decreased the rejection of Cs to different extents in accordance to the order of anions' radii as SO4(2-)>Cl(-)>NO3(-)>F(-). The variations in Sr rejection were influenced by the electrostatic interactions between Sr(2+) and the membrane. In addition, humic acid (HA) lowered the rejection of Cs and caused significant membrane flux decline, but did not change the rejection of Sr. Sr also aggravated HA fouling of the membrane. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Performance evaluation of reverse osmosis technology for selected antibiotics removal from synthetic pharmaceutical wastewater

    Science.gov (United States)

    2012-01-01

    This study addresses the possibility for low pressure reverse osmosis membrane (RE 2521, CSM) process to serve as an alternative to remove selected antibiotics (ampicillin and amoxicillin) from synthetic wastewater by changing operating conditions such as pH = 3, 6.5 and 10; Pressure = 9, 11 and13 (bar); antibiotic concentration = 10, 255 and 500(mg/L), and temperature = 20, 30 and 40°C. The experiment was designed based on Box-benken, which is a Response Surface methodology design (RSM), using Design Expert software. The concentration of antibiotics was measured by applying a UV-spectrophotometer (Cecil), at the wavelength of 254 nm. Results showed a range of rejection percentage from 73.52% to 99.36% and 75.1% to 98.8%, for amoxicillin and ampicillin, respectively. Considering the solute rejections and the membrane porosity show that the prevailing rejection mechanism of the examined antibiotics by the membrane was the size exclusion effect. The permeate flux for both of the antibiotics was 12–18.73 L/m2.h. Although the permeate flux and antibiotic rejection are influenced by operating pressure, pH, and temperature individually, the interaction between operating parameters did not have noticeable effects. According to the results obtained in this study, the application of RO membrane is recommended for the selected antibiotics to be removed to a considerable degree (up to 95%). PMID:23369431

  7. Downstream processing of reverse osmosis brine: Characterisation of potential scaling compounds.

    Science.gov (United States)

    Zaman, Masuduz; Birkett, Greg; Pratt, Christopher; Stuart, Bruce; Pratt, Steven

    2015-09-01

    Reverse osmosis (RO) brine produced at a full-scale coal seam gas (CSG) water treatment facility was characterized with spectroscopic and other analytical techniques. A number of potential scalants including silica, calcium, magnesium, sulphates and carbonates, all of which were present in dissolved and non-dissolved forms, were characterized. The presence of spherical particles with a size range of 10-1000 nm and aggregates of 1-10 microns was confirmed by transmission electron microscopy (TEM). Those particulates contained the following metals in decreasing order: K, Si, Sr, Ca, B, Ba, Mg, P, and S. Characterization showed that nearly one-third of the total silicon in the brine was present in the particulates. Further, analysis of the RO brine suggested supersaturation and precipitation of metal carbonates and sulphates during the RO process should take place and could be responsible for subsequently capturing silica in the solid phase. However, the precipitation of crystalline carbonates and sulphates are complex. X-ray diffraction analysis did not confirm the presence of common calcium carbonates or sulphates but instead showed the presence of a suite of complex minerals, to which amorphous silica and/or silica rich compounds could have adhered. A filtration study showed that majority of the siliceous particles were less than 220 nm in size, but could still be potentially captured using a low molecular weight ultrafiltration membrane.

  8. Novel Fouling-Reducing Coatings for Ultrafiltration, Nanofiltration, and Reverse Osmosis Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Benny Freeman

    2008-08-31

    Polymeric membranes could potentially be the most flexible and viable long-term strategy for treatment of produced water from oil and gas production. However, widespread use of membranes, including reverse osmosis (RO) membranes, for produced water purification is hindered due to fouling caused by the impurities present in the water. Fouling of RO membranes is likely caused by surface properties including roughness, hydrophilicity, and charge, so surface modification is the most widely considered approach to improve the fouling properties of current RO membranes. This project focuses on two main approaches to surface modification: coating and grafting. Hydrophilic coating and grafting materials based on poly(ethylene glycol) (PEG) are applied to commercial RO membranes manufactured by Dow FilmTec and GE. Crossflow filtration experiments are used to determine the fouling resistance of modified membranes, and compare their performance to that of unmodified commercial RO membranes. Grafting and coating are shown to be two alternative methods of producing modified membranes with improved fouling resistance.

  9. Contaminants of emerging concern in reverse osmosis brine concentrate from indirect/direct water reuse applications.

    Science.gov (United States)

    Romeyn, Travis R; Harijanto, Wesley; Sandoval, Sofia; Delagah, Saied; Sharbatmaleki, Mohamadali

    2016-01-01

    Water shortage is becoming more common due to droughts and global population increases resulting in the increasing popularity of water reuse to create new water sources. Reverse osmosis (RO) membrane systems are popular in these applications since they can produce drinking water quality effluent. Unfortunately, RO systems have the drawback of generating concentrate streams that contain contaminants rejected by the membrane including chemicals of emerging concern (CECs). CECs are chemicals such as hormones, steroids, pesticides, pharmaceuticals, and personal care products that are used for their intended purpose and then released into wastewater. CECs are believed to be detrimental to aquatic wildlife health and pose an unknown human health risk. This research gathered the existing knowledge on CEC presence in concentrate, available proven concentrate treatment methods, their CEC removal abilities, and current CEC regulations. It was found that 127 CECs have been measured in RO concentrate with 100 being detected at least once. The most potent treatment process available is UV/H2O2 as it offers the highest removal rates for the widest range of chemicals. The less expensive process of ozone/biologically activated carbon offers slightly lower removal abilities. This comprehensive report will provide the groundwork for better understanding, regulating and treating concentrate stream CECs.

  10. Permeability and selectivity of reverse osmosis membranes: correlation to swelling revisited.

    Science.gov (United States)

    Dražević, Emil; Košutić, Krešimir; Freger, Viatcheslav

    2014-02-01

    Membrane swelling governs both rejection of solutes and permeability of polymeric membranes, however very few data have been available on swelling in water of salt-rejecting reverse osmosis (RO) membranes. This study assesses swelling, thickness and their relation to water permeability for four commercial polyamide (PA) RO membranes (SWC4+, ESPA1, XLE and BW30) using atomic force microscopy (AFM) and attenuated total reflection Fourier transform IR spectroscopy (ATR-FTIR). ATR-FTIR offered a significantly improved estimate of the actual barrier thickness of PA, given AFM is biased by porosity ("fluffy parts") or wiggling of the active layer or presence of a coating layer. Thus obtained intrinsic permeability (permeability times thickness) and selectivity of aromatic polyamides plotted versus swelling falls well on a general trend, along with previously reported data on several common materials showing RO and NF selectivity. The observed general trend may be rationalized by viewing the polymers as a random composite medium containing molecularly small pores. The results suggest that the combination of a rigid low dielectric matrix, limiting the pore size, with multiple hydrophilic H-bonding sites may be a common feature of RO/NF membranes, allowing both high permeability and selectivity.

  11. Nuclide separation modeling through reverse osmosis membranes in radioactive liquid waste

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Sik [KEPCO Engineering and Construction, Gimcheon (Korea, Republic of)

    2015-12-15

    The aim of this work is to investigate the transport mechanism of radioactive nuclides through the reverse osmosis (RO) membrane and to estimate its effectiveness for nuclide separation from radioactive liquid waste. An analytical model is developed to simulate the RO separation, and a series of experiments are set up to confirm its estimated separation behavior. The model is based on the extended Nernst-Plank equation, which handles the convective flux, diffusive flux, and electromigration flux under electroneutrality and zero electric current conditions. The distribution coefficient which arises due to ion interactions with the membrane material and the electric potential jump at the membrane interface are included as boundary conditions in solving the equation. A high Peclet approximation is adopted to simplify the calculation, but the effect of concentration polarization is included for a more accurate prediction of separation. Cobalt and cesium are specifically selected for the experiments in order to check the separation mechanism from liquid waste composed of various radioactive nuclides and nonradioactive substances, and the results are compared with the estimated cobalt and cesium rejections of the RO membrane using the model. Experimental and calculated results are shown to be in excellent agreement. The proposed model will be very useful for the prediction of separation behavior of various radioactive nuclides by the RO membrane.

  12. Compositions and constituents of freshwater dissolved organic matter isolated by reverse osmosis.

    Science.gov (United States)

    Zhang, Yulong; Huang, Wen; Ran, Yong; Mao, Jingdong

    2014-08-15

    Dissolved organic matter (DOM) from riverine and lacustrine water was isolated using a reverse osmosis (RO) system. Solid-state (13)C nuclear magnetic resonance ((13)C NMR) was used to quantitatively evaluate the compositions and constituents of DOM, which are compared with previous investigations on marine DOM. Results indicated that concentration factor (CF) was a key metric controlling yield and sorption of DOM on the RO system. The sorption was likely non-selective, based on the (13)C NMR and δ(13)C analyses. Carbohydrates and lipids accounted for 25.0-41.5% and 30.2-46.3% of the identifiable DOM, followed by proteins (18.2-19.8%) and lignin (7.17-12.8%). The freshwater DOM contained much higher alkyl and aromatic C but lower alkoxyl and carboxyl C than marine DOM. The structural difference was not completely accounted for by using structure of high molecular weight (HMW) DOM, suggesting a size change involved in transformations of DOM during the transport from rivers to oceans.

  13. Effect of membrane bioreactor solids retention time on reverse osmosis membrane fouling for wastewater reuse.

    Science.gov (United States)

    Farias, Elizabeth L; Howe, Kerry J; Thomson, Bruce M

    2014-02-01

    The effect of the solids retention time (SRT) in a membrane bioreactor (MBR) on the fouling of the membranes in a subsequent reverse osmosis (RO) process used for wastewater reuse was studied experimentally using a pilot-scale treatment system. The MBR-RO pilot system was fed effluent from the primary clarifiers at a large municipal wastewater treatment plant. The SRT in the MBRs was adjusted to approximately 2, 10, and 20 days in three experiments. The normalized specific flux through the MBR and RO membranes was evaluated along with inorganic and organic constituents in the influent and effluent of each process. Increasing the SRT in the MBR led to an increase in the removal of bulk DOC, protein, and carbohydrates, as has been observed in previous studies. Increasing the SRT led to a decrease in the fouling of the MBR membranes, which is consistent with previous studies. However, the opposite trend was observed for fouling of the RO membranes; increasing the SRT of the MBR resulted in increased fouling of the RO membranes. These results indicate that the constituents that foul MBR membranes are not the same as those that foul RO membranes; to be an RO membrane foulant in a MBR-RO system, the constituents must first pass through the MBR membranes without being retained. Thus, an intermediate value of SRT may be best choice of operating conditions in an MBR when the MBR is followed by RO for wastewater reuse.

  14. Effect of gamma irradiation at intermediate doses on the performance of reverse osmosis membranes

    Science.gov (United States)

    Combernoux, Nicolas; Labed, Véronique; Schrive, Luc; Wyart, Yvan; Carretier, Emilie; Moulin, Philippe

    2016-07-01

    The goal of this study is to explain the degradation of Polyamide (PA) composite reverse osmosis membrane (RO) in function of the irradiation dose. Irradiations were performed with a gamma 60Co source in wet conditions and under oxygen atmosphere. For different doses of 0.2 and 0.5 MGy with a constant dose rate of 0.5 kGy h-1, RO membranes performances (NaCl retention, permeability) were studied before and after irradiation. ATR-FTIR, ion chromatography and gas chromatography were used to characterize structural modification. Results showed that the permeability of RO membranes irradiated at 0.2 MGy exhibited a small decrease, related to scissions of the PVA coating. However, retention did not change at this dose. At 0.5 MGy, permeability showed a large increase of a factor around 2 and retention began to decrease from 99% to 95%. Chromatography measurements revealed a strong link between permselectivity properties variation, ion leakage and oxygen consumption. Add to ATR-FTIR observations, these results emphasized that the cleavages of amide and ester bonds were observed at 0.5 MGy, more precisely the loss of hydrogen bonds between polyamide chains. By different analysis, modifications of the polysulfone layer occur until a dose of 0.2 MGy.

  15. Performance of landfill leachate treatment system with disc-tube reverse osmosis units

    Institute of Scientific and Technical Information of China (English)

    Yanping LIU; Xiujin LI; Baozhen WANG; Shuo LIU

    2008-01-01

    Reverse osmosis system with the disc-tube module (DT-RO) was applied to treat landfill leachate on full scale at the Changshengqiao Sanitary Landfill, Chongqing City, China. In the first six-mouth operation phase, the treatment performance of DT-RO system had been excel-lent and stable. The removal rate of chemical oxygen demand (COD), total organic carbon (TOC), electrical con-ductivity (EC), and ammonia nitrogen (NH3-N) reached 99.2-99.7%, 99.2%, 99.6%, and over 98%, respectively. The rejection of Ca2+,Ba2+, and Mg2+ was over 99.9%, respectively. Suspended solid (SS) was not detected in prod-uct water. Effective methods had been adopted to control membrane fouling, of which chemical cleaning is of utmost importance to guarantee the long smooth operation of the DT-RO system. The DT-RO system is cleaned in turns with Cleaner A and Cleaner C. At present, the 1st stage cleaning cycle by Cleaner A and Cleaner C is conducted every 100 and 500 h, respectively, depending on raw the water quality.

  16. Production of grape juice powder obtained by freeze-drying after concentration by reverse osmosis

    Directory of Open Access Journals (Sweden)

    Poliana Deyse Gurak

    2013-12-01

    Full Text Available This study aimed to evaluate the freeze-drying process for obtaining grape juice powder by reverse osmosis using 50% grape juice pre-concentrated (28.5 °Brix and 50% hydrocolloids (37.5% maltodextrin and 12.5% arabic gum. The morphology of the glassy food showed the absence of crystalline structure, which was the amorphous wall that protected the contents of the powder. The samples were stored in clear and dark containers at room temperature, evaluated for their physical (X-ray diffraction for 65 days and chemical (polyphenol content stability for 120 days. During the storage time in plastic vessels, samples remained physically stable (amorphous and the phenolic concentration was constant, indicating the potentiality of this technique to obtain a stable product with a high concentration of phenolic compounds. Therefore, the freeze-drying process promoted the encapsulation of concentrated grape juice increasing its stability and shelf life, as well as proving to be an applicable process to food industry

  17. Extending the life-cycle of reverse osmosis membranes: A review.

    Science.gov (United States)

    Coutinho de Paula, Eduardo; Amaral, Míriam Cristina Santos

    2017-05-01

    The reverse osmosis (RO) technology for desalination and demineralization serves the global water crisis context, both technically and economically, and its market is growing. However, RO membranes have a limited life-cycle and are often disposed of in landfills. The impacts caused by the disposal of thousands of tonnes per annum of RO membranes have grown dramatically around the world. Waste prevention should have a high priority and take effect before the end-of-life phase of a product is reached. In this review, a summary is presented of the main advances in the performance of the RO technology and the membrane lifespan. Afterwards, this paper reviews the most important relevant literature and summarizes the key findings of the research on reusing and recycling the discarded modules for the purpose of extending the life-cycle of the RO membranes. In addtion, there are some recent researches that indicated recycling RO membranes for use by the microfiltration or ultrafiltration separation processes is a promising solution to the disposal problem. However, there are many gaps and differences in procedures and results. This article also discusses and brings to light key parameters involved and controversies about oxidative treatment of discarded RO membranes.

  18. Nuclide separation modeling through reverse osmosis membranes in radioactive liquid waste

    Directory of Open Access Journals (Sweden)

    Byung-Sik Lee

    2015-12-01

    Full Text Available The aim of this work is to investigate the transport mechanism of radioactive nuclides through the reverse osmosis (RO membrane and to estimate its effectiveness for nuclide separation from radioactive liquid waste. An analytical model is developed to simulate the RO separation, and a series of experiments are set up to confirm its estimated separation behavior. The model is based on the extended Nernst–Plank equation, which handles the convective flux, diffusive flux, and electromigration flux under electroneutrality and zero electric current conditions. The distribution coefficient which arises due to ion interactions with the membrane material and the electric potential jump at the membrane interface are included as boundary conditions in solving the equation. A high Peclet approximation is adopted to simplify the calculation, but the effect of concentration polarization is included for a more accurate prediction of separation. Cobalt and cesium are specifically selected for the experiments in order to check the separation mechanism from liquid waste composed of various radioactive nuclides and nonradioactive substances, and the results are compared with the estimated cobalt and cesium rejections of the RO membrane using the model. Experimental and calculated results are shown to be in excellent agreement. The proposed model will be very useful for the prediction of separation behavior of various radioactive nuclides by the RO membrane.

  19. 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.

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

    KAUST Repository

    Farhat, N.M.

    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.

  1. 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.

  2. Impact of microfiltration treatment of secondary wastewater effluent on biofouling of reverse osmosis membranes.

    Science.gov (United States)

    Herzberg, Moshe; Berry, David; Raskin, Lutgarde

    2010-01-01

    The effects of microfiltration (MF) as pretreatment for reverse osmosis (RO) on biofouling of RO membranes were analyzed with secondary wastewater effluents. MF pretreatment reduced permeate flux decline two- to three-fold, while increasing salt rejection. Additionally, the oxygen uptake rate (OUR) in the biofouling layer of the RO membrane was higher for an RO system that received pretreated secondary wastewater effluent compared to a control RO system that received untreated secondary effluent, likely due to the removal of inert particulate/colloidal matter during MF. A higher cell viability in the RO biofilm was observed close to the membrane surface irrespective of pretreatment, which is consistent with the biofilm-enhanced concentration polarization effect. Bacterial 16S rRNA gene clone library analysis revealed dominant biofilm communities of Proteobacteria and Bacteroidetes under all conditions. The Cramer-von Mises test statistic showed that MF pretreatment did not significantly change the bacterial community structure of RO membrane biofilms, though it affected bacterial community structure of non-membrane-associated biofilms (collected from the feed tank wall). The finding that the biofilm community developed on the RO membrane was not influenced by MF pretreatment may imply that RO membranes select for a conserved biofilm community.

  3. Reverse osmosis plant maintenance and efficacy in chronic kidney disease endemic region in Sri Lanka.

    Science.gov (United States)

    Jayasumana, Channa; Ranasinghe, Omesh; Ranasinghe, Sachini; Siriwardhana, Imalka; Gunatilake, Sarath; Siribaddana, Sisira

    2016-11-01

    Chronic Interstitial Nephritis in Agricultural Communities (CINAC) causes major morbidity and mortality for farmers in North-Central province (NCP) of Sri Lanka. To prevent the CINAC, reverse osmosis (RO) plants are established to purify the water and reduce the exposure to possible nephrotoxins through drinking water. We assessed RO plant maintenance and efficacy in NCP. We have interviewed 10 RO plant operators on plant establishment, maintenance, usage and funding. We also measured total dissolved solids (TDS in ppm) to assess the efficacy of the RO process. Most RO plants were operated by community-based organizations. They provide clean and sustainable water source for many in the NCP for a nominal fee, which tends to be variable. The RO plant operators carry out RO plant maintenance. However, maintenance procedures and quality management practices tend to vary from an operator to another. RO process itself has the ability to lower the TDS of the water. On average, RO process reduces the TDS to 29 ppm. The RO process reduces the impurities in water available to many individuals within CINAC endemic regions. However, there variation in maintenance, quality management, and day-to-day care between operators can be a cause for concern. This variability can affect the quality of water produced by RO plant, its maintenance cost and lifespan. Thus, uniform regulation and training is needed to reduce cost of maintenance and increase the efficacy of RO plants.

  4. Demonstrating ultra-filtration and reverse osmosis performance using size exclusion chromatography.

    Science.gov (United States)

    Henderson, R K; Stuetz, R M; Khan, S J

    2010-01-01

    Advanced water treatment plants employing ultrafiltration (UF) and reverse osmosis (RO) membrane processes are frequently implemented for the production of high-quality recycled water. It is important that process performance is able to be quantified and assessed to ensure it is fit for purpose. This research utilizes size exclusion chromatography with organic carbon, organic nitrogen and UV(254) detection to determine the change in both DOC concentration and character through a UF/3 stage-RO pilot plant. It was determined that 97% of the influent DOC was removed on average to produce a water of less than 0.5 mg L(-1) as C. The UF process removed more than half of the biopolymer fraction, equating to 4.5% DOC removal, while the RO process generally removed all DOC except a small proportion of the low MW humics and acids and low MW neutral fraction. While not changing significantly in concentration, the Stage 3 RO permeate typically contained low concentrations of humic fraction, indicating a change in character and therefore a change in rejection mechanism. Overall, it was determined that while TOC monitoring is important in advanced water treatment systems, improved understanding of the character of the TOC present lends greater insight into the assessment of process performance.

  5. Treatment of vegetable oily wastewater using an integrated microfiltration-reverse osmosis system.

    Science.gov (United States)

    Yu, Xiaoli; Zhong, Zhaoxiang; Xing, Weihong

    2010-01-01

    Vegetable oil processing plants and catering trade often generate a large amount of oil-containing wastewater, which causes serious environmental problems. The objective of this work was to explore the feasibility of vegetable oil wastewater treatment with an integrated microfiltration-reverse osmosis (MF-RO) process. The influence of operational parameters on the separation behaviors were investigated in MF process. In MF continuous process the steady flux was around 90 (L/m(2) h) when the concentrated multiple reached 16, and the oil content in permeate was less than 12 mg/L. In the RO continuous process, antifouling membrane was used to treat permeate from the ceramic membrane process in order to improve the water quality. The RO process had a permeate flux of 24 (L/m(2) h) and water recovery rate of 95%. The permeate from the RO stage was free of oil, and its TOC and conductivity were less than 0.6 mg/L and 50 micros/cm, respectively. The results demonstrated that the two stage membrane process combining MF and RO is highly efficient in the treatment of oil-containing wastewater.

  6. Electro-oxidation of reverse osmosis concentrates generated in tertiary water treatment.

    Science.gov (United States)

    Pérez, G; Fernández-Alba, A R; Urtiaga, A M; Ortiz, I

    2010-05-01

    This work investigates the application of the electro-oxidation technology provided with boron doped diamond (BDD), an electrode material which has shown outstanding properties in oxidation of organic and inorganic compounds, for the treatment of reverse osmosis (RO) concentrates generated in tertiary wastewater treatment plants (WWTP). Chemical oxygen demand (COD), ammonium and several anions were measured during the electro-oxidation process, and the influence of the applied current density (20-200A/m(2)) was analysed on process kinetics. Analytical assessment showed that several emerging pollutants (pharmaceuticals, personal care products, stimulants, etc.) were presented both in the effluent of the secondary WWTP as well as in the RO concentrate. For this reason, a group of 10 emerging pollutants, those found with higher concentrations, was selected in order to test whether electro-oxidation can be also applied for their mitigation. In the removal of emerging pollutants the electrical current density in the range 20-100A/m(2) did not show influence likely due to the mass transfer resistance developed in the process when the oxidized solutes are present in such low concentrations. Their removal rates were fitted to first order expressions, and the apparent kinetic constants for the anodic oxidation of each compound were calculated. Finally, the formation of trihalomethanes (THMs) has been checked; concluding that after selecting the appropriate operational conditions the attained concentration is lower than the standards for drinking water established in European and EPA regulations.

  7. Isotope and ion selectivity in reverse osmosis desalination: geochemical tracers for man-made freshwater.

    Science.gov (United States)

    Kloppmann, Wolfram; Vengosh, Avner; Guerrot, Catherine; Millot, Romain; Pankratov, Irena

    2008-07-01

    A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.

  8. Investigations on the Suitability of Coated Steel Piping System for High Pressure Seawater Reverse Osmosis Application

    Science.gov (United States)

    Mobin, Mohammad

    2010-03-01

    This study deals with the investigations concerning with the suitability of coated steel piping system as an economically viable alternative to costly stainless steel piping for high pressure seawater reverse osmosis (SWRO) application. The piping system selected for investigation is a carbon steel piping coated internally and externally with thermoplastic coating (coating powder Plascoat PPA 571). The performance of thermoplastic coating was investigated by conducting SWRO pilot plant test, salt spray test, mechanical tests and testing of the coating under crevices (both in pilot plant and laboratory), and for leachable organics and inorganics (both in laboratory and pilot plant test). The testing of coating in the pilot plant resulted in the formation of some blisters on the internal surface of the pipes. The blisters were broken causing the corrosion of underneath steel. The coating showed a poor resistance to salt fog test. In general, the coating performed satisfactorily under the crevices but showed blistering on either side of the test panels. The adhesive strength of the coating was found to be poor; however, it showed good flexibility. The results of chemical analysis did not show the leaching of organic or inorganic pollutants from the coating.

  9. State of the art and review on the treatment technologies of water reverse osmosis concentrates.

    Science.gov (United States)

    Pérez-González, A; Urtiaga, A M; Ibáñez, R; Ortiz, I

    2012-02-01

    The growing demand for fresh water is partially satisfied by desalination plants that increasingly use membrane technologies and among them reverse osmosis to produce purified water. Operating with water recoveries from 35% to 85% RO plants generate huge volumes of concentrates containing all the retained compounds that are commonly discharged to water bodies and constitute a potentially serious threat to marine ecosystems; therefore there is an urgent need for environmentally friendly management options of RO brines. This paper gives an overview on the potential treatments to overcome the environmental problems associated to the direct discharge of RO concentrates. The treatment options have been classified according to the source of RO concentrates and the maturity of the technologies. For the sake of clarity three different sources of RO concentrates are differentiated i) desalination plants, ii) tertiary processes in WWTP, and iii) mining industries. Starting with traditional treatments such as evaporation and crystallization other technologies that have emerged in last years to reduce the volume of the concentrate before disposal and with the objective of achieving zero liquid discharge and recovery of valuable compounds from these effluents are also reviewed. Most of these emerging technologies have been developed at laboratory or pilot plant scale (see Table 1). With regard to RO concentrates from WWTP, the manuscript addresses recent studies that are mainly focused on reducing the organic pollutant load through the application of innovative advanced oxidation technologies. Finally, works that report the treatment of RO concentrates from industrial sources are analyzed as well.

  10. Characterisation and removal of recalcitrants in reverse osmosis concentrates from water reclamation plants.

    Science.gov (United States)

    Bagastyo, Arseto Y; Keller, Jurg; Poussade, Yvan; Batstone, Damien J

    2011-03-01

    Water reclamation plants frequently utilise reverse osmosis (RO), generating a concentrated reject stream as a by-product. The concentrate stream contains salts, and dissolved organic compounds, which are recalcitrant to biological treatment, and may have an environmental impact due to colour and embedded nitrogen. In this study, we characterise organic compounds in RO concentrates (ROC) and treated ROC (by coagulation, adsorption, and advanced oxidation) from two full-scale plants, assessing the diversity and treatability of colour and organic compounds containing nitrogen. One of the plants was from a coastal catchment, while the other was inland. Stirred cell membrane fractionation was applied to fractionate the treated ROC, and untreated ROC along with chemical analysis (DOC, DON, COD), colour, and fluorescence excitation-emission matrix (EEM) scans to characterise changes within each fraction. In both streams, the largest fraction contained 10 kDa molecules, with 17-34% of organic compounds as COD. Iron coagulation affected a wider size range, with better removal of organics (41-49% as COD) at the same molar dosage. As with iron, adsorption reduced organics of a broader size range, including organic nitrogen (26-47%). Advanced oxidation (UV/H2O2) was superior for complete decolourisation and provided superior organics removal (50-55% as COD).

  11. Use of horizontal subsurface flow constructed wetlands to treat reverse osmosis concentrate of rolling wastewater.

    Science.gov (United States)

    Xu, Jingcheng; Zhao, Gang; Huang, Xiangfeng; Guo, Haobo; Liu, Wei

    2017-03-04

    According to the characteristics of the reverse osmosis concentrate (ROC) generated from iron and steel company, we used three sets of parallel horizontal subsurface flow (HSF) constructed wetlands (CWs) with different plants and substrate layouts to treat the high-salinity wastewater. The plant growth and removal efficiencies under saline condition were evaluated. The evaluation was based entirely on routinely collected water quality data and the physical and chemical characteristics of the plants (Phragmites australis, Typha latifolia, Iris wilsonii, and Scirpus planiculmis). The principal parameters of concern in the effluent were chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP). The results showed that the CWs were able to remove COD, TN, and TP from ROC. S. planiculmis was not suitable for the treatment of high-saline wastewater. The sequence of metals accumulated in CW plants was K>Ca>Na>Mg>Zn>Cu. More than 70% of metals were accumulated in the aboveground of P. australis. The CW filled with gravel and manganese ore and planted with P. australis and T. latifolia had the best performance of pollutant removal, with average removal of 49.96%, 39.45%, and 72.01% for COD, TN, and TP, respectively. The effluent water quality met the regulation in China. These results suggested that HSF CW planted with P. australis and T. latifolia can be applied for ROC pollutants removal.

  12. Planning and Design of Seawater Reverse Osmosis Desalination Plants Marine Outfalls

    Science.gov (United States)

    Maalouf, S.; Yeh, W. W.

    2011-12-01

    Increasing demands for water in urban areas and agricultural zones in arid and semi-arid regions have urged planners and regulators to look for alternative renewable water sources. Worldwide, seawater reverse osmosis (SWRO) desalination plants have become an essential supply source for the production of fresh water in such regions. Disposal of their wastes, however, has not been fully and properly addressed. This study presents a strategy for the analysis and design of optimal disposal systems of hypersaline wastes that are generated by SWRO desalination plants. The study evaluates current disposal methods and recommends ways to effectively employ multiport marine outfalls for this purpose. Such outfalls emerged as reliable means for conveying wastes from process plants, to include wastewater treatment and power plants, into the coastal waters. Their proper use, however, in conjunction with SWRO desalination plants is still in its beginning stage, and much work needs to be done to employ them effectively. Therefore, the main objective of this research is to provide design engineers with effective procedures that meet environmental permitting requirements and restrictions, while ascertaining adequate hydrodynamic performance. The study is tested by employing a simulation model and examining its reliability under many parameter perturbation scenarios. This is further extended by providing a solution to the same problem using a heuristic approach.

  13. 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.

  14. Assessment of silt density index (SDI) as fouling propensity parameter in reverse osmosis (RO) desalination systems

    KAUST Repository

    Rachman, Rinaldi

    2013-01-01

    Due to its simplicity, silt density index (SDI) is extensively used in reverse osmosis systems despite its limitations in predicting membrane fouling. Employing a reliable fouling index with good reproducibility and precision is necessary. The aim of this investigation is to assess the reliability of SDI in order to understand the reasons for the low level of precision and accuracy. Different commercial SDI membranes and feed water quality were used in this study. Results showed the existence of membrane properties\\' variation within manufacturers, which then causes a lack of accuracy in fouling risk estimation. The nature of particles during SDI filtration provides information that particle concentration and size play a significant role in SDI quantification with substantial representation given by particles with size close to membrane nominal pore size. Moreover, turbidity-assisted SDI measurements along with determination of ultrafiltration permeate and clean water fouling potential, establish the indication of nonfouling-related phenomena involved on SDI measurement such as natural organic matter adsorption and hydrodynamic conditions that alters during filtration. Additionally, it was found that the latter affects the sensitivity of SDI by being represented by some portions of SDI values. © 2013 Desalination Publications.

  15. Removal of Crotamiton from Reverse Osmosis Concentrate by a TiO2/Zeolite Composite Sheet

    Directory of Open Access Journals (Sweden)

    Qun Xiang

    2017-07-01

    Full Text Available Reverse osmosis (RO concentrate from wastewater reuse facilities contains concentrated emerging pollutants, such as pharmaceuticals. In this research, a paper-like composite sheet consisting of titanium dioxide (TiO2 and zeolite was synthesized, and removal of the antipruritic agent crotamiton from RO concentrate was studied using the TiO2/zeolite composite sheet. The RO concentrate was obtained from a pilot-scale municipal secondary effluent reclamation plant. Effective immobilization of the two powders in the sheet made it easy to handle and to separate the photocatalyst and adsorbent from purified water. The TiO2/zeolite composite sheet showed excellent performance for crotamiton adsorption without obvious inhibition by other components in the RO concentrate. With ultraviolet irradiation, crotamiton was simultaneously removed through adsorption and photocatalysis. The photocatalytic decomposition of crotamiton in the RO concentrate was significantly inhibited by the water matrix at high initial crotamiton concentrations, whereas rapid decomposition was achieved at low initial crotamiton concentrations. The major degradation intermediates were also adsorbed by the composite sheet. This result provides a promising method of mitigating secondary pollution caused by the harmful intermediates produced during advanced oxidation processes. The cyclic use of the HSZ-385/P25 composite sheet indicated the feasibility of continuously removing crotamiton from RO concentrate.

  16. Selective removal of arsenic and monovalent ions from brackish water reverse osmosis concentrate.

    Science.gov (United States)

    Xu, Pei; Capito, Marissa; Cath, Tzahi Y

    2013-09-15

    Concentrate disposal and management is a considerable challenge for the implementation of desalination technologies, especially for inland applications where concentrate disposal options are limited. This study has focused on selective removal of arsenic and monovalent ions from brackish groundwater reverse osmosis (RO) concentrate for beneficial use and safe environmental disposal using in situ and pre-formed hydrous ferric oxides/hydroxides adsorption, and electrodialysis (ED) with monovalent permselective membranes. Coagulation with ferric salts is highly efficient at removing arsenic from RO concentrate to meet a drinking water standard of 10 μg/L. The chemical demand for ferric chloride however is much lower than ferric sulfate as coagulant. An alternative method using ferric sludge from surface water treatment plant is demonstrated as an efficient adsorbent to remove arsenic from RO concentrate, providing a promising low cost, "waste treat waste" approach. The monovalent permselective anion exchange membranes exhibit high selectivity in removing monovalent anions over di- and multi-valent anions. The transport of sulfate and phosphate through the anion exchange membranes was negligible over a broad range of electrical current density. However, the transport of divalent cations such as calcium and magnesium increases through monovalent permselective cation exchange membranes with increasing current density. Higher overall salt concentration reduction is achieved around limiting current density while higher normalized salt removal rate in terms of mass of salt per membrane area and applied energy is attained at lower current density because the energy unitization efficiency decreases at higher current density.

  17. Use of simulated evaporation to assess the potential for scale formation during reverse osmosis desalination

    Science.gov (United States)

    Huff, G.F.

    2004-01-01

    The tendency of solutes in input water to precipitate efficiency lowering scale deposits on the membranes of reverse osmosis (RO) desalination systems is an important factor in determining the suitability of input water for desalination. Simulated input water evaporation can be used as a technique to quantitatively assess the potential for scale formation in RO desalination systems. The technique was demonstrated by simulating the increase in solute concentrations required to form calcite, gypsum, and amorphous silica scales at 25??C and 40??C from 23 desalination input waters taken from the literature. Simulation results could be used to quantitatively assess the potential of a given input water to form scale or to compare the potential of a number of input waters to form scale during RO desalination. Simulated evaporation of input waters cannot accurately predict the conditions under which scale will form owing to the effects of potentially stable supersaturated solutions, solution velocity, and residence time inside RO systems. However, the simulated scale-forming potential of proposed input waters could be compared with the simulated scale-forming potentials and actual scale-forming properties of input waters having documented operational histories in RO systems. This may provide a technique to estimate the actual performance and suitability of proposed input waters during RO.

  18. Reverse osmosis desalination of chitosan cross-linked graphene oxide/titania hybrid lamellar membranes.

    Science.gov (United States)

    Deng, Hui; Sun, Penzhan; Zhang, Yingjiu; Zhu, Hongwei

    2016-07-08

    With excellent mass transport properties, graphene oxide (GO)-based lamellar membranes are believed to have great potential in water desalination. In order to quantify whether GO-based membranes are indeed suitable for reverse osmosis (RO) desalination, three sub-micrometer thick GO-based lamellar membranes: GO-only, reduced GO (RGO)/titania (TO) nanosheets and RGO/TO/chitosan (CTS) are prepared, and their RO desalination performances are evaluated in a home-made RO test apparatus. The photoreduction of GO by TO improves the salt rejection, which increases slowly with the membrane thickness. The RGO/TO/CTS hybrid membranes exhibit higher rejection rates of only about 30% (greater than threefold improvement compared with a GO-only membrane) which is still inferior compared to other commercial RO membranes. The low rejection rates mainly arise from the pressure-induced weakening of the ion-GO interlayer interactions. Despite the advantages of simple, low-cost preparation, high permeability and selectivity of GO-based lamellar membranes, as the current desalination performances are not high enough to afford practical application, there still remains a great challenge to realize high performance separation membranes for water desalination applications.

  19. Surface Modification of Commercial Aromatic Polyamide Reverse Osmosis Membranes by Crosslinking Treatments

    Institute of Scientific and Technical Information of China (English)

    WEI Xinyu; WANG Zhi; XU Jun; WANG Jixiao; WANG Shichang

    2013-01-01

    Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites (N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.

  20. Using nanocomposite materials technology to understand and control reverse osmosis membrane compaction

    KAUST Repository

    Pendergast, Mary Theresa M.

    2010-10-01

    Composite reverse osmosis (RO) membranes were formed by interfacial polymerization of polyamide thin films over pure polysulfone and nanocomposite-polysulfone support membranes. Nanocomposite support membranes were formed from amorphous non-porous silica and crystalline microporous zeolite nanoparticles. For each hand-cast membrane, water flux and NaCl rejection were monitored over time at two different applied pressures. Nanocomposite-polysulfone supported RO membranes generally had higher initial permeability and experienced less flux decline due to compaction than pure polysulfone supported membranes. In addition, observed salt rejection tended to increase as flux declined from compaction. Crosssectional SEM images verified significant reduction in thickness of pure polysulfone supports, whereas nanocomposites better resisted compaction due to enhanced mechanical stability imparted by the nanoparticles. A conceptual model was proposed to explain the mechanistic relationship between support membrane compaction and observed changes in water flux and salt rejection. As the support membrane compacts, skin layer pore constriction increased the effective path length for diffusion through the composite membranes, which reduced both water and salt permeability identically. However, experimental salt permeability tended to decline to a greater extent than water permeability; hence, the observed changes in flux and rejection might also be related to structural changes in the polyamide thin film. © 2010 Elsevier B.V. All rights reserved.

  1. Rapid novel test for the determination of biofouling potential on reverse osmosis membranes.

    Science.gov (United States)

    Manalo, Cervinia V; Ohno, Masaki; Okuda, Tetsuji; Nakai, Satoshi; Nishijima, Wataru

    2016-01-01

    A novel method was proposed to determine biofouling potential by direct analysis of a reverse osmosis (RO) membrane through fluorescence intensity analysis of biofilm formed on the membrane surface, thereby incorporating fouling tendencies of both feedwater and membrane. Evaluation of the biofouling potential on the RO membrane was done by accelerated biofilm formation through soaking of membranes in high biofouling potential waters obtained by adding microorganisms and glucose in test waters. The biofilm formed on the soaked membrane was quantified by fluorescence intensity microplate analysis. The soaking method's capability in detecting biofilm formation was confirmed when percentage coverage obtained through fluorescence microscopy and intensity values exhibited a linear correlation (R(2) = 0.96). Continuous cross-flow experiments confirmed the ability and reliability of the soaking method in giving biofouling potential on RO membranes when a good correlation (R(2) = 0.87) between intensity values of biofilms formed on the membrane during soaking and filtration conditions was obtained. Applicability of the test developed was shown when three commercially available polyamide (PA) RO membranes were assessed for biofouling potential. This new method can also be applied for the determination of biofouling potential in water with more than 3.6 mg L(-1) easily degradable organic carbon.

  2. Feasibility of supercritical CO₂ treatment for controlling biofouling in the reverse osmosis process.

    Science.gov (United States)

    Mun, Sungmin; Baek, Youngbin; Kim, Cholin; Lee, Youn-Woo; Yoon, Jeyong

    2012-01-01

    Physical cleaning and/or chemical cleaning have been generally used to control biofouling in the reverse osmosis (RO) process. However, conventional membrane cleaning methods to control biofouling are limited due to the generation of by-products and the potential for damage to the RO membranes. In this study, supercritical carbon dioxide (SC CO(2)) treatment, an environmentally friendly technique, was introduced to control biofouling in the RO process. SC CO(2) (100 bar at 35°C) treatment was performed after biofouling was induced on a commercial RO membrane using Pseudomonas aeruginosa PA01 GFP as a model bacterial strain. P. aeruginosa PA01 GFP biofilm cells were reduced on the RO membrane by >8 log within 30 min, and the permeate flux was sufficiently recovered in a laboratory-scale RO membrane system without any significant damage to the RO membrane. These results suggest that SC CO(2) treatment is a promising alternative membrane cleaning technique for biofouling in the RO process.

  3. Systematic analysis of micromixers to minimize biofouling on reverse osmosis membranes.

    Science.gov (United States)

    Altman, Susan J; McGrath, Lucas K; Jones, Howland D T; Sanchez, Andres; Noek, Rachel; Clem, Paul; Cook, Adam; Ho, Clifford K

    2010-06-01

    Micromixers, UV-curable epoxy traces printed on the surface of a reverse osmosis membrane, were tested on a cross-flow system to determine their success at reducing biofouling. Biofouling was quantified by measuring the rate of permeate flux decline and the median bacteria concentration on the surface of the membrane (as determined by fluorescence intensity counts due to nucleic acid stains as measured by hyperspectral imaging). The micromixers do not appear to significantly increase the pressure needed to maintain the same initial permeate flux and salt rejection. Chevrons helped prevent biofouling of the membranes in comparison with blank membranes. The chevron design controlled where the bacteria adhered to the membrane surface. However, blank membranes with spacers had a lower rate of permeate flux decline than the membranes with chevrons despite having greater bacteria concentrations on their surfaces. With better optimization of the micromixer design, the micromixers could be used to control where the bacteria will adhere to the surface and create a more biofouling resistant membrane that will help to drive down the cost of water treatment.

  4. Advanced treatment of the reverse osmosis concentrate produced during reclamation of municipal wastewater.

    Science.gov (United States)

    Dialynas, Emmanuel; Mantzavinos, Dionissios; Diamadopoulos, Evan

    2008-11-01

    The work investigated the treatment of the concentrate produced from the reverse osmosis treatment of an MBR effluent. Two conventional chemical processes, coagulation and activated carbon adsorption, and three advanced oxidation processes (electrochemical treatment, photocatalysis and sonolysis) were applied. Coagulation with alum gave dissolved organic carbon (DOC) removals up to 42%, while FeCl(3) achieved higher removals (52%) at lower molar doses. Adsorption with granular activated carbon showed the highest DOC removals up to 91.3% for 5 g/L. The adsorption isotherm was linear with a non-adsorbable organic fraction of around 1.2 mg/L DOC. The three oxidation methods employed, electrolytic oxidation over a boron-doped diamond electrode, UVA/TiO2 photocatalysis and sonolysis at 80 kHz, showed similar behavior: during the first few minutes of treatment there was a moderate removal of DOC followed by further oxidation at a very slow rate. Electrolytic oxidation was capable of removing up to 36% at 17.8A after 30 min of treatment, sonolysis removed up to 34% at 135W after 60 min, while photocatalysis was capable of removing up to 50% at 60 min.

  5. Coking wastewater treatment for industrial reuse purpose: combining biological processes with ultrafiltration, nanofiltration and reverse osmosis.

    Science.gov (United States)

    Jin, Xuewen; Li, Enchao; Lu, Shuguang; Qiu, Zhaofu; Sui, Qian

    2013-08-01

    A full-scale plant using anaerobic, anoxic and oxic processes (A1/A2/O), along with a pilot-scale membrane bioreactor (MBR), nanofiltration (NF) and reverse osmosis (RO) integrated system developed by Shanghai Baosteel Chemical Co. Ltd., was investigated to treat coking wastewater for industrial reuse over a period of one year. The removals reached 82.5% (COD), 89.6% (BOD), 99.8% (ammonium nitrogen), 99.9% (phenol), 44.6% (total cyanide (T-CN)), 99.7% (thiocyanide (SCN-)) and 8.9% (fluoride), during the A1/A2/O biological treatment stage, and all parameters were further reduced by over 96.0%, except for fluoride (86.4%), in the final discharge effluent from the currently operating plant. The pilot-scale MBR process reduced the turbidity to less than 0.65 NTU, and most of the toxic organic compounds were degraded or intercepted by the A1/A2/O followed MBR processes. In addition, parameters including COD, T-CN, total nitrogen, fluoride, chloride ion, hardness and conductivity were significantly reduced by the NF-RO system to a level suitable for industrial reuse, with a total water production ratio of 70.7%. However, the concentrates from the NF and RO units were highly polluted and should be disposed of properly or further treated before being discharged.

  6. Reverse osmosis concentrate treatment via a PAC-MF accumulative countercurrent adsorption process.

    Science.gov (United States)

    Zhao, Chunxia; Gu, Ping; Cui, Hangyu; Zhang, Guanghui

    2012-01-01

    Organic pollutants in reverse osmosis (RO) concentrates from wastewater reclamation are mainly comprised of low molecular weight biorefractory compounds. Generally, advanced oxidation methods for oxidizing these organics require a relatively high level of energy consumption. In addition, conventional adsorption removal methods require a large dose of activated carbon. However, the dose can be reduced if its full adsorption capacity can be used. Therefore, the combined technology of powdered activated carbon (PAC) adsorption and microfiltration (MF) membrane filtration was studied to develop a countercurrent two-stage adsorption process. A PAC accumulative adsorption prediction method was proposed based on the verification of a PAC multi-stage adsorption capacity equation. Moreover, the prediction method was amended for a more accurate prediction of the effluent quality because adsorption isotherm constants were affected by the initial adsorbate concentration. The required PAC dose for the accumulative countercurrent two-stage adsorption system was 0.6 g/L, whereas that of the conventional adsorption process was 1.05 g/L when the dilution factor(F) was 0.1 and the COD and DOC removal rates were set to 70% and 68.1%, respectively. Organic pollutants were satisfactorily removed with less consumption of PAC. Effluent from this combined technology can be further reclaimed by an RO process to improve the overall recovery rate to between 91.0% and 93.8% with both economic and environmental benefits.

  7. Distillery wastewater treatment by the membrane-based nanofiltration and reverse osmosis processes.

    Science.gov (United States)

    Nataraj, Sanna Kotrappanavar; Hosamani, Kallappa M; Aminabhavi, Tejraj M

    2006-07-01

    A hybrid nanofiltration (NF) and reverse osmosis (RO) pilot plant was used to remove the color and contaminants of the distillery spent wash. The feasibility of the membranes for treating wastewater from the distillery industry by varying the feed pressure (0-70 bar) and feed concentration was tested on the separation performance of thin-film composite NF and RO membranes. Color removal by NF and a high rejection of 99.80% total dissolved solids (TDS), 99.90% of chemical oxygen demand (COD) and 99.99% of potassium was achieved from the RO runs, by retaining a significant flux as compared to pure water flux, which shows that membranes were not affected by fouling during wastewater run. The pollutant level in permeates were below the maximum contaminant level as per the guidelines of the World Health Organization and the Central Pollution Control Board specifications for effluent discharge (less than 1,000 ppm of TDS and 500 ppm of COD).

  8. Comparison of tertiary treatment by nanofiltration and reverse osmosis for water reuse in denim textile industry.

    Science.gov (United States)

    Ben Amar, Nihel; Kechaou, Noura; Palmeri, John; Deratani, André; Sghaier, Ali

    2009-10-15

    The wastewaters resulting from different baths of a dyeing factory specialized in denim fabric are collected and treated by an activated sludge plant. This study investigated the coupling of activated sludge treatment with either nanofiltration (NF) or reverse osmosis (RO) to recycle water and reuse it in the process. We first conducted NF experiments with a HL membrane in different configurations: dead end and cross-flow for flat sheets and also in spiral wound form. Results on water permeation and salt rejection show that performances are configuration dependent. Then, for the study of the NF/RO textile wastewater treatment, experiments were conducted with spiral wound membranes in order to be closest to the industrial configuration. After analyzing the removal efficiencies of suspended solids and chemical oxygen demand (COD) of the treatment plant, we conducted NF experiments using an HL2514TF spiral wound membrane preceded by ultrafiltration (UF) treatment. We used as well an RO membrane (AG2514TF) to compare performances in water yield and quality for the same pumping costs. The results show that NF allows higher yield, while respecting the Tunisian standard of water reuse (CODreuse of the water in the process.

  9. Nanofiltration vs. reverse osmosis for the removal of emerging organic contaminants in water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-01-01

    Reverse osmosis (RO) in existing water reuse facilities is a water industry standard. However, that approach may be questioned taking into consideration that "tight" NF can be equal or "better" than RO. NF can achieve the same removals of RO membranes when dealing with emerging organic contaminants (pharmaceuticals, pesticides, endocrine disruptors and others). Experiments using 18 emerging contaminants were performed using membranes NF200 and NF90 at bench-scale units, and for a more complete study, results of NF and RO pilot and fullscale experiments where compared to our experimental results. The removal results showed that NF can remove many emerging contaminants. The average removal by tight NF was 82% for neutral contaminants and 97% for ionic contaminants. The average removal by RO was 85% for neutral contaminants and 99% for ionic contaminants. Aquifer recharge and recovery (ARR) followed by NF can effectively remove emerging contaminants with removals over 90% when loose NF membranes are used. © 2011 2011 Desalination Publications. All rights reserved.

  10. Membrane distillation for wastewater reverse osmosis concentrate treatment with water reuse potential

    KAUST Repository

    Naidu, Gayathri

    2016-11-29

    Membrane distillation (MD) was evaluated as a treatment option of wastewater reverse osmosis concentrate (WWROC) discharged from wastewater reclamation plants (WRPs). A direct contact MD (DCMD), at obtaining 85% water recovery of WWROC showed only 13–15% flux decline and produced good quality permeate (10–15 µS/cm, 99% ion rejection) at moderate feed temperature of 55 °C. Prevalent calcium carbonate (CaCO3) deposition on the MD membrane occurred in treating WWROC at elevated concentrations. The combination of low salinity and loose CaCO3 adhesion on the membrane did not significantly contribute to DCMD flux decline. Meanwhile, high organic content in WWROC (58–60 mg/L) resulted in a significant membrane hydrophobicity reduction (70% lower water contact angle than virgin membrane) attributed to low molecular weight organic adhesion onto the MD membrane. Granular activated carbon (GAC) pretreatment helped in reducing organic contents of WWROC by 46–50%, and adsorbed a range of hydrophobic and hydrophilic micropollutants. This ensured high quality water production by MD (micropollutants-free) and enhanced its reuse potential. The MD concentrated WWROC was suitable for selective ion precipitation, promising a near zero liquid discharge in WRPs.

  11. 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.

  12. Polishing Step Purification of High-Strength Wastewaters by Nanofiltration and Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    Jinxiang Zhou

    2016-03-01

    Full Text Available This article reports findings on the use of nanofiltration (NF and reverse osmosis (RO for secondary treatment of high-strength rendering facility wastewaters following an ultrafiltration step. These wastewaters present significant challenges to classical treatment technologies. Constant-pressure, direct-flow membrane filtration experiments were done to screen for flux and effluent water permeate quality of ten commercial NF and RO membranes. All membranes tested were effective in reducing total dissolved salts (TDS and chemical oxygen demand (COD; however, only two membranes (Koch MPF-34 and Toray 70UB gave sufficiently stable flux values to warrant longer term cross-flow filtration studies. Cross-flow flux measurements, scanning electron microscopy (SEM, X-ray dispersive spectroscopy (EDS, and attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR indicated that both membranes were eventually fouled by organic and inorganic foulants; however, the Toray 70UB RO membrane yielded a capacity of 1600 L/m2 prior to cleaning. A preliminary economic analysis compared the estimated costs of energy and consumables for a dual-stage UF/RO membrane process and dissolved air floatation (DAF and found membrane process costs could be less than about 40% of the current DAF process.

  13. Enhanced Wettability and Transport Control of Ultrafiltration and Reverse Osmosis Membranes with Grafted Polyelectrolytes.

    Science.gov (United States)

    Gao, Kai; Kearney, Logan T; Wang, Ruocun; Howarter, John A

    2015-11-11

    End-functionalized poly(acrylic acid) (PAA-silane) was synthesized with reversible addition-fragmentation chain-transfer (RAFT) polymerization and attached to both polysulfone ultrafiltration (UF) and polyamide reverse osmosis (RO) membranes through a nonimpairing, one-step grafting to approach in order to improve membrane surface wettability with minimal impact on membrane transport performance. After PAA grafting, composition and morphology changes on the membrane surface were characterized with Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Static contact angle on PAA grafted membranes exhibited an increase in surface hydrophilicity and hence a potential enhancement in antifouling performance. The native contact angle on the polysulfone membrane systems was 86° and was reduced to 24° after modification, while the polyamide film contact angle decreased from 58° to 25°. The PAA layer endowed the porous UF membrane with dynamic control over the permeability and selectivity through the manipulation of the solution pH. The UF membrane with a 35 nm average pore size displayed a 115% increase in flux when the contact solution was changed from pH 11 to pH 3. This effect was diminished to 70% and 32% as the average pore size decreased to 20 and 10 nm, respectively. Modified RO membranes displayed no reduction in membrane performance indicating that the underlying materials were unaffected by the modification environment or added polymer. Model polyamide and polysulfone surfaces were reacted with the PAA-silane inside a quartz crystal microbalance (QCM) to help inform the deposition behavior for the respective membrane chemistries.

  14. Osmotic versus conventional membrane bioreactors integrated with reverse osmosis for water reuse: Biological stability, membrane fouling, and contaminant removal.

    Science.gov (United States)

    Luo, Wenhai; Phan, Hop V; Xie, Ming; Hai, Faisal I; Price, William E; Elimelech, Menachem; Nghiem, Long D

    2017-02-01

    This study systematically compares the performance of osmotic membrane bioreactor - reverse osmosis (OMBR-RO) and conventional membrane bioreactor - reverse osmosis (MBR-RO) for advanced wastewater treatment and water reuse. Both systems achieved effective removal of bulk organic matter and nutrients, and almost complete removal of all 31 trace organic contaminants investigated. They both could produce high quality water suitable for recycling applications. During OMBR-RO operation, salinity build-up in the bioreactor reduced the water flux and negatively impacted the system biological treatment by altering biomass characteristics and microbial community structure. In addition, the elevated salinity also increased soluble microbial products and extracellular polymeric substances in the mixed liquor, which induced fouling of the forward osmosis (FO) membrane. Nevertheless, microbial analysis indicated that salinity stress resulted in the development of halotolerant bacteria, consequently sustaining biodegradation in the OMBR system. By contrast, biological performance was relatively stable throughout conventional MBR-RO operation. Compared to conventional MBR-RO, the FO process effectively prevented foulants from permeating into the draw solution, thereby significantly reducing fouling of the downstream RO membrane in OMBR-RO operation. Accumulation of organic matter, including humic- and protein-like substances, as well as inorganic salts in the MBR effluent resulted in severe RO membrane fouling in conventional MBR-RO operation. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  15. 反渗透复合膜最新研究进展%Progress on thin-film composite(TFC)reverse osmosis membrane

    Institute of Scientific and Technical Information of China (English)

    张所波; 张奇峰; 李胜海

    2013-01-01

    Reverse osmosis (RO) membranes have been widely used in seawater desalination,ultrapure water production,wastewater treatment,pharmaceutical and biological industries.The whole aromatic polyamide thin-film composite membrane (TFC) is the most successful reverse osmosis membrane nowadays.The performance of reverse osmosis membrane is decided by the physical structures and chemical properties of the ultra-thin polyamide layer.Progress on reverse osmosis composite membrane,including the formation process of interfacially polymerized composite membrane,novel monomers used for interfacial polymerization,the additives,nano hybrid reverse osmosis membrane,highly chlorine-tolerant reverse osmosis membrane and new characterization methods for reverse osmosis membranes are introduced briefly in this review.%反渗透膜在海水淡化、超纯水制备、污水处理、制药及生物技术等领域得到了广泛应用.目前,最成功的反渗透膜是通过界面聚合方法制备的以交联聚酰胺为分离皮层的复合膜.交联聚酰胺皮层的结构和性质对最终反渗透膜的分离性能起关键作用.本文简要介绍了界面聚合复合膜的形成过程和结构、新型界面聚合功能单体、界面聚合反应添加剂、纳米杂化反渗透复合膜、高耐氯氧化性反渗透膜,以及反渗透复合膜表征方法创新等方面的研究进展和发展趋势.

  16. Application of ceramic membranes for seawater reverse osmosis (SWRO) pre-treatment

    KAUST Repository

    Hamad, Juma

    2013-05-30

    Low-pressure (microfiltration/ultrafiltration (MF/UF)) membranes are being increasingly used as pre-treatment, prior to seawater reverse osmosis (SWRO). The objective of pre-treatment before reverse osmosis (RO) membranes is to remove undesirable and particulate fouling materials (algae, suspended and colloidal particles). Also, a pre-treatment barrier reduces organics and provides better feed water quality for RO membranes. MF and UF pre-treatment prior to SWRO provides Low Silt Density Index (SDI) values recommended for RO operation. Ceramic membranes are more attractive as they made of more chemically resistant materials, which allow for more stable operation and aggressive backwashing (BW) and cleaning. A pilot plant with a monolith ceramic MF membrane (0.1 μm pore size) from METAWATER was used to carry out the study. Red Sea water pumped from a distance of 700 m offshore from Thuwal (Kingdom of Saudi Arabia) was used as feed water. The pilot plant was operated automatically at constant flux of 150 LMH that involved BW, air flushing and forward flushing at the end of filtration cycle. Seawater permeates were used for hydraulic BW, while sodium hypochlorite, citric acid and sodium hydroxide were used for chemical cleaning (CIP) to restore the membrane permeability after use. Filtration cycles of 2.5 h were adopted for initial experiments. Aggressive BW flux of 1,800 LMH for 15 s, air flushing of 4 bars for 10 s and forward flushing of 300 LMH for 40 s were applied for regular membrane hydraulic cleaning. The increase of membrane resistances over time was monitored. Further studies were also performed by using Anopore ceramic membranes AAO100 (pore sizes of 0.1 μm) using a constant pressure bench-scale set-up. The feed water and permeate were analysed using an SDI unit, flow cytometre (FCM) and liquid chromatography with organic carbon detection (LC-OCD). The results showed that ceramic membrane filtration reduced the SDI15 of seawater from 6.1 to 2.1 which

  17. Removal of organic micro-pollutants (phenol, aniline and nitrobenzene) via forward osmosis (FO) process: Evaluation of FO as an alternative method to reverse osmosis (RO).

    Science.gov (United States)

    Cui, Yue; Liu, Xiang-Yang; Chung, Tai-Shung; Weber, Martin; Staudt, Claudia; Maletzko, Christian

    2016-03-15

    In this study, we have explored and compared the effectiveness of using (1) lab-fabricated forward osmosis (FO) membranes under both FO and reverse osmosis (RO) modes and (2) commercially available RO membranes under the RO mode for the removal of organic micro-pollutants. The lab-fabricated FO membranes are thin film composite (TFC) membranes consisting of a polyamide layer and a porous substrate cast from three different materials; namely, Matrimid, polyethersulfone (PESU) and sulfonated polyphenylene sulfone (sPPSU). The results show that the FO mode is superior to the RO mode in the removal of phenol, aniline and nitrobenzene from wastewater. The rejections of all three TFC membranes to all the three organic micro-pollutants under the FO processes are higher than 72% and can be even higher than 90% for aniline when a 1000 ppm aromatic aqueous solution and 1 M NaCl are employed as feeds. These performances outperform the results obtained from themselves and commercially available RO membranes under the RO mode. In addition, the rejection can be maintained even when treating a more concentrated feed solution (2000 ppm). The removal performance can be further enhanced by using a more concentrated draw solution (2 M). The water flux is almost doubled, and the rejection increment can reach up to 17%. Moreover, it was observed that annealing as a post-treatment would help compact the membrane selective layer and further enhance the separating efficiency. The obtained organic micro-pollutant rejections and water fluxes under various feasible operating conditions indicate that the FO process has potential to be a viable treatment for wastewater containing organic micro-pollutants.

  18. Removal of organic micro-pollutants (phenol, aniline and nitrobenzene) via forward osmosis (FO) process: Evaluation of FO as an alternative method to reverse osmosis (RO)

    KAUST Repository

    Cui, Yue

    2016-01-05

    In this study, we have explored and compared the effectiveness of using (1) lab-fabricated forward osmosis (FO) membranes under both FO and reverse osmosis (RO) modes and (2) commercially available RO membranes under the RO mode for the removal of organic micro-pollutants. The lab-fabricated FO membranes are thin film composite (TFC) membranes consisting of a polyamide layer and a porous substrate cast from three different materials; namely, Matrimid, polyethersulfone (PESU) and sulfonated polyphenylene sulfone (sPPSU). The results show that the FO mode is superior to the RO mode in the removal of phenol, aniline and nitrobenzene from wastewater. The rejections of all three TFC membranes to all the three organic micro-pollutants under the FO processes are higher than 72% and can be even higher than 90% for aniline when a 1000 ppm aromatic aqueous solution and 1 M NaCl are employed as feeds. These performances outperform the results obtained from themselves and commercially available RO membranes under the RO mode. In addition, the rejection can be maintained even when treating a more concentrated feed solution (2000 ppm). The removal performance can be further enhanced by using a more concentrated draw solution (2 M). The water flux is almost doubled, and the rejection increment can reach up to 17%. Moreover, it was observed that annealing as a post-treatment would help compact the membrane selective layer and further enhance the separating efficiency. The obtained organic micro-pollutant rejections and water fluxes under various feasible operating conditions indicate that the FO process has potential to be a viable treatment for wastewater containing organic micro-pollutants.

  19. Study of the effect of nanoparticles and surface morphology on reverse osmosis and nanofiltration membrane productivity.

    Science.gov (United States)

    Fang, Yuming; Duranceau, Steven J

    2013-08-15

    To evaluate the significance of reverse osmosis (RO) and nanofiltration (NF) surface morphology on membrane performance, productivity experiments were conducted using flat-sheet membranes and three different nanoparticles, which included SiO2, TiO2 and CeO2. In this study, the productivity rate was markedly influenced by membrane surface morphology. Atomic force microscopy (AFM) analysis of membrane surfaces revealed that the higher productivity decline rates associated with polyamide RO membranes as compared to that of a cellulose acetate NF membrane was due to the inherent ridge-and-valley morphology of the active layer. The unique polyamide active layer morphology was directly related to the surface roughness, and was found to contribute to particle accumulation in the valleys causing a higher flux decline than in smoother membranes. Extended RO productivity experiments using laboratory grade water and diluted pretreated seawater were conducted to compare the effect that different nanoparticles had on membrane active layers. Membrane flux decline was not affected by particle type when the feed water was laboratory grade water. On the other hand, membrane productivity was affected by particle type when pretreated diluted seawater served as feed water. It was found that CeO2 addition resulted in the least observable flux decline, followed by SiO2 and TiO2. A productivity simulation was conducted by fitting the monitored flux data into a cake growth rate model, where the model was modified using a finite difference method to incorporate surface thickness variation into the analysis. The ratio of cake growth term (k1) and particle back diffusion term (k2) was compared in between different RO and NF membranes. Results indicated that k2 was less significant for surfaces that exhibited a higher roughness. It was concluded that the valley areas of thin-film membrane surfaces have the ability to capture particles, limiting particle back diffusion.

  20. Spatial and temporal evolution of organic foulant layers on reverse osmosis membranes in wastewater reuse applications.

    Science.gov (United States)

    Farias, Elizabeth L; Howe, Kerry J; Thomson, Bruce M

    2014-07-01

    Advanced treatment to remove trace constituents and emerging contaminants is an important consideration for wastewater treatment for potable reuse, and reverse osmosis (RO) can be a suitable technology to provide the necessary level of treatment. However, membrane fouling by biological and organic matter is a concern. This research examined the development of the RO membrane fouling layer using a bench-scale membrane bioreactor operating at different solids retention times (SRTs), followed by a custom-designed RO test cell. The RO test cell contained stacked plates that sandwich five sheets of RO membrane material, which can be extracted for autopsy at separate times over the course of an experiment without disturbing the remaining membranes. The MBR-RO system was run continuously for 2 weeks at each SRT. The RO membranes were stained for live and dead cells, protein, and carbohydrate-like materials, and visualized using confocal laser scanning microscopy. Images of the stained foulant layers were obtained at different depths within the foulant layer at each time point for all SRT conditions. As the RO foulant layer developed, changes occurred in the distribution and morphology of the live cells and carbohydrates, but not the proteins. These trends were similar for all three SRT conditions tested. RO membrane fouling increased with increased MBR SRT, and the highest SRT had the highest ratios of live to dead cells and carbohydrate-like material to dead cells. The autopsied membranes were also analyzed for protein and carbohydrate content, and it was found that the carbohydrate concentration on the membranes after 14 days increased as the SRT increased.

  1. Designing cost-effective seawater reverse osmosis system under optimal energy options

    Energy Technology Data Exchange (ETDEWEB)

    Gilau, Asmerom M.; Small, Mitchell J. [Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2008-04-15

    Today, three billion people around the world have no access to clean drinking water and about 1.76 billion people live in areas already facing a high degree of water stress. This paper analyzes the cost-effectiveness of a stand alone small-scale renewable energy-powered seawater reverse osmosis (SWRO) system for developing countries. In this paper, we have introduced a new methodology; an energy optimization model which simulates hourly power production from renewable energy sources. Applying the model using the wind and solar radiation conditions for Eritrea, East Africa, we have computed hourly water production for a two-stage SWRO system with a capacity of 35 m{sup 3}/day. According to our results, specific energy consumption is about 2.33 kW h/m{sup 3}, which is a lower value than that achieved in most of the previous designs. The use of a booster pump, energy recovery turbine and an appropriate membrane, allows the specific energy consumption to be decreased by about 70% compared to less efficient design without these features. The energy recovery turbine results in a reduction in the water cost of about 41%. Our results show that a wind-powered system is the least cost and a PV-powered system the most expensive, with finished water costs of about 0.50 and 1.00/m{sup 3}, respectively. By international standards, for example, in China, these values are considered economically feasible. Detailed simulations of the RO system design, energy options, and power, water, and life-cycle costs are presented. (author)

  2. Using microbial desalination cells to reduce water salinity prior to reverse osmosis

    KAUST Repository

    Mehanna, Maha

    2010-01-01

    A microbial desalination cell (MDC) is a new method to reduce the salinity of one solution while generating electrical power from organic matter and bacteria in another (anode) solution. Substantial reductions in the salinity can require much larger volumes of the anode solution than the saline water, but any reduction of salinity will benefit the energy efficiency of a downstream reverse osmosis (RO) desalination system. We investigated here the use of an MDC as an RO pre-treatment method using a new type of air-cathode MDC containing three equally sized chambers. A single cycle of operation using a 1 g L -1 acetate solution reduced the conductivity of salt water (5 g L-1 NaCl) by 43 ± 6%, and produced a maximum power density of 480 mW m-2 with a coulombic efficiency of 68 ± 11%. A higher concentration of acetate (2 g L-1) reduced solution conductivity by 60 ± 7%, and a higher salt concentration (20 g L-1 NaCl) reduced solution conductivity by 50 ± 7%. The use of membranes with increased ion exchange capacities further decreased the solution conductivity by 63 ± 2% (20 g L-1 NaCl). These results demonstrate substantial (43-67%) desalination of water is possible using equal volumes of anode solution and salt water. These results show that MDC treatment could be used to substantially reduce salt concentrations and thus energy demands for downstream RO processing, while at the same time producing electrical power. © 2010 The Royal Society of Chemistry.

  3. Application of nanofiltration and reverse osmosis membranes to the salty and polluted surface water.

    Science.gov (United States)

    Koyuncu, I; Yazgan, M

    2001-01-01

    Nanofiltration (NF) (TFC-S) and reverse osmosis (RO) (TFC-HR) membranes were evaluated for the treatment of salty and polluted Kucukcekmece Lake used as a drinking water reservoir for the Istanbul City. A thin film composite type of spiral wound membrane (2 m2 area) was used. Experiments were conducted at different pressures, pH ranges and temperatures. Flowrate was about 300 l/h. The flux decreased with increasing pH. Highest rejections were obtained for all anionic and cationic ions in the pH range of 6.0-8.5. Several permeation runs were carried out for the pressure range of 6-12 bar for TFC-S and TFC-HR membranes. According to the Spiegler-Kedem model, the permeate flux (Jv) is linearly related to the applied hydraulic pressure (deltaP). Lp values were calculated by linear regression. Salt rejection was seen to increase with the increasing of operating pressure due to increase of solvent flux. Na+, Mg+2, Ca+2, Cl- and SO4(-2) rejections and z1 and z2 constants have been determined and z values of cations were in the order of zMg > zCa > zNa and similarly those of anions were in the order of zSO4 > zCl. The Spiegler-Kedem model was able to correlate well the experimental data by fitting different best values of P and sigma, respectively for all ions. Best fit values of P and sigma were obtained by regression of the data according to the model.

  4. N-nitrosamine rejection by reverse osmosis membranes: a full-scale study.

    Science.gov (United States)

    Fujioka, Takahiro; Khan, Stuart J; McDonald, James A; Roux, Annalie; Poussade, Yvan; Drewes, Jörg E; Nghiem, Long D

    2013-10-15

    This study aims to provide longitudinal and spatial insights to the rejection of N-nitrosamines by reverse osmosis (RO) membranes during sampling campaigns at three full-scale water recycling plants. Samples were collected at all individual filtration stages as well as at a cool and a warm weather period to elucidate the impact of recovery and feed temperature on the rejection of N-nitrosamines. N-nitrosodimethylamine (NDMA) was detected in all RO feed samples varying between 7 and 32 ng/L. Concentrations of most other N-nitrosamines in the feed solutions were determined to be lower than their detection limits (3-5 ng/L) but higher concentrations were detected in the feed after each filtration stage. As a notable exception, in one plant, N-nitrosomorpholine (NMOR) was observed at high concentrations in RO feed (177-475 ng/L) and permeate (34-76 ng/L). Overall rejection of NDMA among the three RO systems varied widely from 4 to 47%. Data presented here suggest that the feed temperature can influence rejection of NDMA. A considerable variation in NDMA rejection across the three RO stages (14-78%) was also observed. Overall NMOR rejections were consistently high ranging from 81 to 84%. On the other hand, overall rejection of N-nitrosodiethylamine (NDEA) varied from negligible to 53%, which was considerably lower than values reported in previous laboratory-scale studies. A comparison between results reported here and the literature indicates that there can be some discrepancy in N-nitrosamine rejection data between laboratory- and full-scale studies probably due to differences in water recoveries and operating conditions (e.g. temperature, membrane fouling, and hydraulic conditions). Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  5. 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

    2015-01-01

    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. PMID:25636842

  6. 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.

  7. Study of the Effect of Nanoparticles and Surface Morphology on Reverse Osmosis and Nanofiltration Membrane Productivity

    Science.gov (United States)

    Fang, Yuming; Duranceau, Steven J.

    2013-01-01

    To evaluate the significance of reverse osmosis (RO) and nanofiltration (NF) surface morphology on membrane performance, productivity experiments were conducted using flat-sheet membranes and three different nanoparticles, which included SiO2, TiO2 and CeO2. In this study, the productivity rate was markedly influenced by membrane surface morphology. Atomic force microscopy (AFM) analysis of membrane surfaces revealed that the higher productivity decline rates associated with polyamide RO membranes as compared to that of a cellulose acetate NF membrane was due to the inherent ridge-and-valley morphology of the active layer. The unique polyamide active layer morphology was directly related to the surface roughness, and was found to contribute to particle accumulation in the valleys causing a higher flux decline than in smoother membranes. Extended RO productivity experiments using laboratory grade water and diluted pretreated seawater were conducted to compare the effect that different nanoparticles had on membrane active layers. Membrane flux decline was not affected by particle type when the feed water was laboratory grade water. On the other hand, membrane productivity was affected by particle type when pretreated diluted seawater served as feed water. It was found that CeO2 addition resulted in the least observable flux decline, followed by SiO2 and TiO2. A productivity simulation was conducted by fitting the monitored flux data into a cake growth rate model, where the model was modified using a finite difference method to incorporate surface thickness variation into the analysis. The ratio of cake growth term (k1) and particle back diffusion term (k2) was compared in between different RO and NF membranes. Results indicated that k2 was less significant for surfaces that exhibited a higher roughness. It was concluded that the valley areas of thin-film membrane surfaces have the ability to capture particles, limiting particle back diffusion. PMID:24956946

  8. Removal of haloacetic acids from swimming pool water by reverse osmosis and nanofiltration.

    Science.gov (United States)

    Yang, Linyan; She, Qianhong; Wan, Man Pun; Wang, Rong; Chang, Victor W-C; Tang, Chuyang Y

    2017-06-01

    Recent studies report high concentrations of haloacetic acids (HAAs), a prevalent class of toxic disinfection by-products, in swimming pool water (SPW). We investigated the removal of 9 HAAs by four commercial reverse osmosis (RO) and nanofiltration (NF) membranes. Under typical SPW conditions (pH 7.5 and 50 mM ionic strength), HAA rejections were >60% for NF270 with molecular weight cut-off (MWCO) equal to 266 Da and equal or higher than 90% for XLE, NF90 and SB50 with MWCOs of 96, 118 and 152 Da, respectively, as a result of the combined effects of size exclusion and charge repulsion. We further included 7 neutral hydrophilic surrogates as molecular probes to resolve the rejection mechanisms. In the absence of strong electrostatic interaction (e.g., pH 3.5), the rejection data of HAAs and surrogates by various membranes fall onto an identical size-exclusion (SE) curve when plotted against the relative-size parameter, i.e., the ratio of molecular radius over membrane pore radius. The independence of this SE curve on molecular structures and membrane properties reveals that the relative-size parameter is a more fundamental SE descriptor compared to molecular weight. An effective molecular size with the Stokes radius accounting for size exclusion and the Debye length accounting for electrostatic interaction was further used to evaluate the rejection. The current study provides valuable insights on the rejection of trace contaminants by RO/NF membranes. Copyright © 2017. Published by Elsevier Ltd.

  9. Effects of feed solution chemistry on low pressure reverse osmosis filtration of cesium and strontium

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Shiyuan, E-mail: dingshiyuan@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Yang, Yu, E-mail: yangyu@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Huang, Haiou, E-mail: huanghaiou@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Liu, Hengchen, E-mail: 799599501@qq.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Hou, Li-an, E-mail: houlian678@hotmail.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing 100875 (China); Xi’an High-Tech Institute, No. 2, Tongxin Street, Baqiao District, Xi’an 710025 (China)

    2015-08-30

    Highlights: • A low pressure spiral wound RO membrane can reject Cs and Sr efficiently. • The rejection of Cs and Sr is dependent on feed pH and co-existing ions. • Donnan exclusion and electrostatic interaction govern the rejection of Cs and Sr. • The differences of filtration mechanism were influenced by the size of ions. • Sr could strengthen the irreversible membrane fouling resistance with HA. - Abstract: The objective of this study was to identify the removal mechanisms of radionuclides by reverse osmosis (RO) membranes under conditions relevant to full-scale water treatment. For this purpose, the effects of feed solution chemistry on the removal of Cs and Sr by a low pressure RO system was investigated by systematically varying membrane surface charge, ionic composition, and organic matter concentrations. The results showed that the effects of solution chemistry on the filtration of Cs and Sr were related to their hydrated ionic radius, resulting in the predominance of the Donnan’s effect and electrostatic interactions, respectively. Consequently, the rejection of Cs increased more pronouncedly than Sr with the increases of feed concentration. Due to the Donnan’s effect, different anions decreased the rejection of Cs to different extents in accordance to the order of anions’ radii as SO{sub 4}{sup 2−} > Cl{sup −} > NO{sub 3}{sup −} > F{sup −}. The variations in Sr rejection were influenced by the electrostatic interactions between Sr{sup 2+} and the membrane. In addition, humic acid (HA) lowered the rejection of Cs and caused significant membrane flux decline, but did not change the rejection of Sr. Sr also aggravated HA fouling of the membrane.

  10. Coking wastewater treatment for industrial reuse purpose: Combining biological processes with ultrafiltration, nanofiltration and reverse osmosis

    Institute of Scientific and Technical Information of China (English)

    Xuewen Jin; Enchao Li; Shuguang Lu; Zhaofu Qiu; Qian Sui

    2013-01-01

    A full-scale plant using anaerobic,anoxic and oxic processes (A1/A2/O),along with a pilot-scale membrane bioreactor (MBR),nanofiltration (NF) and reverse osmosis (RO) integrated system developed by Shanghai Baosteel Chemical Co.Ltd.,was investigated to treat coking wastewater for industrial reuse over a period of one year.The removals reached 82.5% (COD),89.6% (BOD),99.8% (ammonium nitrogen),99.9% (phenol),44.6% (total cyanide (T-CN)),99.7% (thiocyanide (SCN-)) and 8.9% (fluoride),during the A1/A2/O biological treatment stage,and all parameters were further reduced by over 96.0%,except for fluoride (86.4%),in the final discharge effluent from the currently operating plant.The pilot-scale MBR process reduced the turbidity to less than 0.65 NTU,and most of the toxic organic compounds were degraded or intercepted by the A1/A2/O followed MBR processes.In addition,parameters including COD,T-CN,total nitrogen,fluoride,chloride ion,hardness and conductivity were significantly reduced by the NF-RO system to a level suitable for industrial reuse,with a total water production ratio of 70.7%.However,the concentrates from the NF and RO units were highly polluted and should be disposed of properly or further treated before being discharged.

  11. Simultaneous nitrogen, phosphorous, and hardness removal from reverse osmosis concentrate by microalgae cultivation.

    Science.gov (United States)

    Wang, Xiao-Xiong; Wu, Yin-Hu; Zhang, Tian-Yuan; Xu, Xue-Qiao; Dao, Guo-Hua; Hu, Hong-Ying

    2016-05-01

    While reverse osmosis (RO) is a promising technology for wastewater reclamation, RO concentrate (ROC) treatment and disposal are important issues to consider. Conventional chemical and physical treatment methods for ROC present certain limitations, such as relatively low nitrogen and phosphorus removal efficiencies as well as the requirement of an extra process for hardness removal. This study proposes a novel biological approach for simultaneous removal of nitrogen, phosphorus, and calcium (Ca(2+)) and magnesium (Mg(2+)) ions from the ROC of municipal wastewater treatment plants by microalgal cultivation and algal biomass production. Two microalgae strains, Chlorella sp. ZTY4 and Scenedesmus sp. LX1, were used for batch cultivation of 14-16 days. Both strains grew well in ROC with average biomass production of 318.7 mg/L and lipid contents up to 30.6%, and nitrogen and phosphorus could be effectively removed with efficiencies of up to 89.8% and 92.7%, respectively. Approximately 55.9%-83.7% Ca(2+) could be removed from the system using the cultured strains. Mg(2+) removal began when Ca(2+) precipitation ceased, and the removal efficiency of the ion could reach up to 56.0%. The most decisive factor influencing Ca(2+) and Mg(2+) removal was chemical precipitation with increases in pH caused by algal growth. The results of this study provide a new biological approach for removing nitrogen, phosphorous, and hardness from ROC. The results suggest that microalgal cultivation presents new opportunities for applying an algal process to ROC treatment. The proposed approach serves dual purposes of nutrient and hardness reduction and production of lipid rich micro-algal biomass.

  12. Ozonation of reverse osmosis concentrate: kinetics and efficiency of beta blocker oxidation.

    Science.gov (United States)

    Benner, Jessica; Salhi, Elisabeth; Ternes, Thomas; von Gunten, Urs

    2008-06-01

    Reverse osmosis (RO) concentrate samples were obtained from a RO-membrane system that uses effluents of wastewater treatment plants (WWTP) as feed water for the production of drinking water. A number of different pharmaceuticals (e.g. antibiotics, contrast media, beta blockers) were found in the WWTP effluent as well as in the RO-concentrate. Overall, a concentration factor (feed:concentrate) of approximately 3-4 was measured. Beta blockers (acebutolol, atenolol, bisoprolol, celiprolol, metoprolol, propranolol, timolol) were found in the range of low ng/L to low microg/L. Because metoprolol and propranolol are classified as potentially toxic to aquatic organisms and all beta blocker molecules have moieties, which are reactive towards ozone (amine groups, activated aromatic rings), it was tested whether ozonation can be applied for their mitigation. Rate constants for the reaction of acebutolol, atenolol, metoprolol and propranolol with ozone and OH radicals were determined. At pH 7 acebutolol, atenolol and metoprolol react with ozone with an apparent second-order rate constant k(O)(3) of about 2,000 M(-1)s(-1), whereas propranolol reacts with approximately 10(5)M(-1)s(-1). The rate constants for the reaction of the selected compounds with OH radicals were determined to be 0.5-1.0 x 10(10)M(-1)s(-1). Experiments with RO concentrate showed that an ozone dose of only 5mg/L resulted in a quantitative removal of propranolol in 0.8s and 10mg O(3)/L oxidized 70% of metoprolol in only 1.2s. Tests with chlorinated and non-chlorinated WWTP effluent showed an increase of ozone stability but a decrease of hydroxyl radical exposure in the samples after chlorination. This may shift the oxidation processes towards direct ozone reactions and favor the degradation of compounds with high k(O)(3).

  13. Study of the Effect of Nanoparticles and Surface Morphology on Reverse Osmosis and Nanofiltration Membrane Productivity

    Directory of Open Access Journals (Sweden)

    Steven J. Duranceau

    2013-08-01

    Full Text Available To evaluate the significance of reverse osmosis (RO and nanofiltration (NF surface morphology on membrane performance, productivity experiments were conducted using flat-sheet membranes and three different nanoparticles, which included SiO2, TiO2 and CeO2. In this study, the productivity rate was markedly influenced by membrane surface morphology. Atomic force microscopy (AFM analysis of membrane surfaces revealed that the higher productivity decline rates associated with polyamide RO membranes as compared to that of a cellulose acetate NF membrane was due to the inherent ridge-and-valley morphology of the active layer. The unique polyamide active layer morphology was directly related to the surface roughness, and was found to contribute to particle accumulation in the valleys causing a higher flux decline than in smoother membranes. Extended RO productivity experiments using laboratory grade water and diluted pretreated seawater were conducted to compare the effect that different nanoparticles had on membrane active layers. Membrane flux decline was not affected by particle type when the feed water was laboratory grade water. On the other hand, membrane productivity was affected by particle type when pretreated diluted seawater served as feed water. It was found that CeO2 addition resulted in the least observable flux decline, followed by SiO2 and TiO2. A productivity simulation was conducted by fitting the monitored flux data into a cake growth rate model, where the model was modified using a finite difference method to incorporate surface thickness variation into the analysis. The ratio of cake growth term (k1 and particle back diffusion term (k2 was compared in between different RO and NF membranes. Results indicated that k2 was less significant for surfaces that exhibited a higher roughness. It was concluded that the valley areas of thin-film membrane surfaces have the ability to capture particles, limiting particle back diffusion.

  14. Effect of engineered environment on microbial community structure in biofilter and biofilm on reverse osmosis membrane

    KAUST Repository

    Jeong, Sanghyun

    2017-07-25

    Four dual media filters (DMFs) were operated in a biofiltration mode with different engineered environments (DMF I and II: coagulation with/without acidification and DMF III and IV: without/with chlorination). Designed biofilm enrichment reactors (BERs) containing the removable reverse osmosis (RO) coupons, were connected at the end of the DMFs in parallel to analyze the biofilm on the RO membrane by DMF effluents. Filtration performances were evaluated in terms of dissolved organic carbon (DOC) and assimilable organic carbon (AOC). Organic foulants on the RO membrane were also quantified and fractionized. The bacterial community structures in liquid (seawater and effluent) and biofilm (DMF and RO) samples were analyzed using 454-pyrosequencing. The DMF IV fed with the chlorinated seawater demonstrated the highest reductions of DOC including LMW-N as well as AOC among the other DMFs. The DMF IV was also effective in reducing organic foulants on the RO membrane surface. The bacterial community structure was grouped according to the sample phase (i.e., liquid and biofilm samples), sampling location (i.e., DMF and RO samples), and chlorination (chlorinated and non-chlorinated samples). In particular, the biofilm community in the DMF IV differed from the other DMF treatments, suggesting that chlorination exerted as stronger selective pressure than pH adjustment or coagulation on the biofilm community. In the DMF IV, several chemoorganotrophic chlorine-resistant biofilm-forming bacteria such as Hyphomonas, Erythrobacter, and Sphingomonas were predominant, and they may enhance organic carbon degradation efficiency. Diverse halophilic or halotolerant organic degraders were also found in other DMFs (i.e., DMF I, II, and III). Various kinds of dominant biofilm-forming bacteria were also investigated in RO membrane samples; the results provided possible candidates that cause biofouling when DMF process is applied as the pretreatment option for the RO process.

  15. Rejection of emerging organic micropollutants in nanofiltration-reverse osmosis membrane applications.

    Science.gov (United States)

    Xu, Pei; Drewes, Jörg E; Bellona, Christopher; Amy, Gary; Kim, Tae-Uk; Adam, Marc; Heberer, Thomas

    2005-01-01

    The rejection of emerging trace organics by a variety of commercial reverse osmosis (RO), nanofiltration (NF), and ultra-low-pressure RO (ULPRO) membranes was investigated using TFC-HR, NF-90, NF-200, TFC-SR2, and XLE spiral membrane elements (Koch Membrane Systems, Wilmington, Massachusetts) to simulate operational conditions for drinking-water treatment and wastewater reclamation. In general, the presence of effluent organic matter (EfOM) improved the rejection of ionic organics by tight NF and RO membranes, as compared to a type-II water matrix (adjusted by ionic strength and hardness), likely as a result of a decreased negatively charged membrane surface. Rejection of ionic pharmaceutical residues and pesticides exceeded 95% by NF-90, XLE, and TFC-HR membranes and was above 89% for the NF-200 membrane. Hydrophobic nonionic compounds, such as bromoform and chloroform, exhibited a high initial rejection, as a result of both hydrophobic-hydrophobic solute-membrane interactions and steric exclusion, but rejection decreased significantly after 10 hours of operation because of partitioning of solutes through the membranes. This resulted in a partial removal of disinfection byproducts by the RO membrane TFC-HR. In a type-II water matrix, the effect of increasing feed water recoveries on rejection of hydrophilic ionic and nonionic compounds was compound-dependent and not consistent for different membranes. The presence of EfOM, however, could neutralize the effect of hydrodynamic operating condition on rejection performance. The ULPRO and tight NF membranes were operated at lower feed pressure, as compared to the TFC-HR, and provided a product water quality similar to a conventional RO membrane, regarding trace organics of interest.

  16. 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.

  17. Role of membrane fouling substances on the rejection of N-nitrosamines by reverse osmosis.

    Science.gov (United States)

    Fujioka, Takahiro; Kodamatani, Hitoshi; Aizawa, Hidenobu; Gray, Stephen; Ishida, Kenneth P; Nghiem, Long D

    2017-07-01

    The impact of fouling substances on the rejection of four N-nitrosamines by a reverse osmosis (RO) membrane was evaluated by characterizing individual organic fractions in a secondary wastewater effluent and deploying a novel high-performance liquid chromatography-photochemical reaction-chemiluminescence (HPLC-PR-CL) analytical technique. The HPLC-PR-CL analytical technique allowed for a systematic examination of the correlation between the fouling level and the permeation of N-nitrosamines in the secondary wastewater effluent and synthetic wastewaters through an RO membrane. Membrane fouling caused by the secondary wastewater effluent led to a notable decrease in the permeation of N-nitrosodimethylamine (NDMA) while a smaller but nevertheless discernible decrease in the permeation of N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) was also observed. Fluorescence spectrometry analysis revealed that major foulants in the secondary wastewater effluent were humic and fulvic acid-like substances. Analysis using the size exclusion chromatography technique also identified polysaccharides and proteins as additional fouling substances. Thus, further examination was conducted using solutions containing model foulants (i.e., sodium alginate, bovine serum albumin, humic acid and two fulvic acids). Similar to the secondary wastewater effluent, membrane fouling with fulvic acid solutions resulted in a decrease in N-nitrosamine permeation. In contrast, membrane fouling with the other model foulants resulted in a negligible impact on N-nitrosamine permeation. Overall, these results suggest that the impact of fouling on the permeation of N-nitrosamines by RO is governed by specific small organic fractions (e.g. fulvic acid-like organics) in the secondary wastewater effluent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Preparation and water desalination properties of POSS-polyamide nanocomposite reverse osmosis membranes

    KAUST Repository

    Duan, Jintang

    2015-01-01

    The application of nanotechnology to thin-film nanocomposites (TFN) is a new route to enhance membrane performance in water desalination. Here, the potential of polyhedral oligomeric silsesquioxane (POSS) as the nanofiller in polyamide (PA) reverse osmosis membranes was systematically investigated. Four POSS materials (P-8Phenyl, P-8NH3Cl, P-8NH2 and P-1NH2) were introduced into the selective layer by physical blending or chemical fixation during standard interfacial polymerization. Water flux and NaCl rejection were measured with 2000ppm NaCl solution under 15.5bar pressure, and SEM and TEM images of membrane selective layers were obtained. Membranes prepared without POSS showed water flux of 20.0±0.5L/m2·h and salt rejection of 98.0±0.2%. TFN membranes prepared with 0.4% (w/v) P-8Phenyl in the organic phase showed a 65% increase in water flux compared to the pristine PA membrane while maintaining high salt rejection. The selective layer of this membrane maintained the typical ridge-and-valley structure of aromatic PA. Results with P-8NH3Cl and P-8NH2 added to the organic phase were similar. TFN membranes prepared with monoamine P-1NH2 in the organic phase had poor water flux of 3.2L/m2·h, a smooth and more hydrophobic surface, and a much thicker (~400nm) selective layer. One of the four POSS compounds studied, P-8NH3Cl, is sufficiently soluble in water for incorporation into the selective layer via the aqueous phase. Membranes were prepared with P-8NH3Cl in the aqueous phase at varying reaction time, loading, and additive (triethylamine) concentration. With these parameters optimized, water flux increased to 35.4L/m2·h.

  19. A comparative study of boron and arsenic (III) rejection from brackish water by reverse osmosis membranes

    KAUST Repository

    Teychene, Benoît

    2013-02-01

    This study aims to compare at lab-scale the rejection efficiency of several reverse osmosis membranes (RO) toward arsenic (III) and boron during the filtration of a synthetic brackish water. The effect of pH and operating conditions on the rejection of each RO membrane was studied. Two types of membrane were investigated: "brackish water" and "sea water" membranes. Our results showed that the metalloid rejection depends on the membrane type, pH and transmembrane pressure applied. Increasing pH above the dissociation constant (pKa) of each specie improves significantly the metalloid rejection by RO membranes, whatever the membrane type. Moreover, at identical operating conditions (pH, transmembrane pressure), results showed that the brackish water membranes have a higher water flux and exhibit lower metalloid rejection. The highest As(III) rejection value for the tested brackish water membranes was 99% obtained at pH = 9.6 and 40 bars, whereas it was found that the sea water RO membranes could highly reject As(III), more than 99%, even at low pH and low pressure (pH = 7.6 and 24 bars).Regarding Boron rejection, similar conclusions could be drawn. The sea water RO membranes exert higher removal, with a high rejection value above 96% over the tested conditions. More generally, this study showed that, whatever the operating conditions or the tested membranes, the boron and As(III) permeate concentrations are below the WHO guidelines. In addition, new data about the boron and arsenic permeability of each tested RO membrane was brought thanks to a theoretical calculation. © 2012 Elsevier B.V.

  20. Experimental study of dye removal from industrial wastewater by membrane technologies of reverse osmosis and nanofiltration

    Directory of Open Access Journals (Sweden)

    Abid Mohammad Fadhil

    2012-12-01

    Full Text Available Abstract Currently, biological method has been utilized in the treatment of wastewater -containing synthetic dyes used by textile industries in Iraq. The present work was devoted to study the operating feasibility using reverse osmosis (RO and nanofiltration (NF membrane systems as an alternative treatment method of wastewater discharged from Iraqi textile mills. Acid red, reactive black and reactive blue dyes were selected, based on the usage rate in Iraq. Effects of dye concentration, pH of solution, feed temperature, dissolved salts and operating pressure on permeate flux and dye rejection were studied. Results at operating conditions of dye concentration = 65 mg/L, feed temperature = 39°C and pressure = 8 bar showed the final dye removal with RO membrane as 97.2%, 99.58% and 99.9% for acid red, reactive black and reactive blue dyes, respectively. With NF membrane, the final dye removal were as 93.77%, 95.67%, and 97% for red, black and blue dyes, respectively. The presence of salt (particularly NaCl in the dye solution resulted in a higher color removal with a permeate flux decline. It was confirmed that pH of solution had a positive impact on dye removal while feed temperature showed a different image. A comparison was made between the results of dye removal in biological and membrane methods. The results showed that membrane method had higher removal potential with lower effective cost. The present study indicates that the use of NF membrane in dye removal from the effluent of Iraqi textile mills is promising.

  1. Experimental Study of Dye Removal from Industrial Wastewater by Membrane Technologies of Reverse Osmosis and Nanofiltration

    Directory of Open Access Journals (Sweden)

    Mohammad Fadhil Abid

    2012-12-01

    Full Text Available Currently, biological method has been utilized in the treatment of wastewater -containing synthetic dyes used by textile industries in Iraq. The present work was devoted to study the operating feasibility using reverse osmosis (RO and nanofiltration (NF membrane systems as an alternative treatment method of wastewater discharged from Iraqi textile mills. Acid red, reactive black and reactive blue dyes were selected, based on the usage rate in Iraq. Effects of dye concentration, pH of solution, feed temperature, dissolved salts and operating pressure on permeate flux and dye rejection were studied. Results at operating conditions of dye concentration?=?65 mg/L, feed temperature?=?39?C and pressure?=?8 bar showed the final dye removal with RO membrane as 97.2%, 99.58% and 99.9% for acid red, reactive black and reactive blue dyes, respectively. With NF membrane, the final dye removal were as 93.77%, 95.67%, and 97% for red, black and blue dyes, respectively. The presence of salt (particularly NaCl in the dye solution resulted in a higher color removal with a permeate flux decline. It was confirmed that pH of solution had a positive impact on dye removal while feed temperature showed a different image. A comparison was made between the results of dye removal in biological and membrane methods. The results showed that membrane method had higher removal potential with lower effective cost. The present study indicates that the use of NF membrane in dye removal from the effluent of Iraqi textile mills is promising.

  2. RESEARCH DEVELOPMENT ON ORGANICS REMOVAL IN REVERSE OSMOSIS CENCENTRATES%反渗透浓水中有机物去除的研究进展

    Institute of Scientific and Technical Information of China (English)

    郭瑞丽; 石玉; 王增长

    2013-01-01

    随着反渗透膜技术在水处理领域的广泛应用,反渗透浓水的处理问题引起了越来越多的关注,特别是城市污水和工业废水反渗透膜处理产生的反渗透浓水,反渗透浓水中的有机物对浓水的排放和回收有很大影响.介绍了反渗透浓水中有机物的去除方法,分析了各种方法的优、缺点,并指出了今后的主要研究发展方向.%With the extensive application of reverse osmosis membrane technology in the water treatment field, reverse osmosis concentrates treatment attracted more and more attention, especially reverse osmosis-concentrates from the treatment of urban sewage and industrial wastewater by reverse osmosis membrane, in which organics have great influence on the disposal and recycling of concentrates. This paper introduces several organics removal methods in reverse osmosis concentrates, and their advantages and disadvantages are also discussed, which points out the future research and development direction.

  3. 反渗透预处理系统问题的分析与措施%Problems Analysis and Solutions for Reverse Osmosis Pretreatment System

    Institute of Scientific and Technical Information of China (English)

    张彬; 李燕

    2011-01-01

    The pretreatment of reverse osmosis feed water generally includes the whole processes from water source to reverse osmosis feed water pump.Cood pretreatment is a necessary condition for reverse osmosis equipment to run steadily. A scheme to improve the pretreatment system was presented after some abnormal situations such as reverse osmosis system polluted etc were analyzed for Shanghai Coking Co., Ltd. 2nd desalted water group.The feed water pollution was eliminated and avoided after remedy, which laid a good foundation for reverse osmosis system to operate reliably.%反渗透给水的预处理一般包括源水到反渗透给水泵之前的一切处理[1].良好的预处理是反渗透装置长期稳定运行的必要条件.通过对上海焦化有限公司除盐水二组反渗透及其预处理系统在开车初期污染频繁、保安过滤器滤芯寿命过短等异常情况进行分析,提出相应的预处理系统改进方案,实施后,消除和减少了给水污染,为反渗透系统的可靠运行打下良好基础.

  4. Practice of Chemical Cleaning of Reverse Osmosis Membrane%反渗透膜化学清洗的实践

    Institute of Scientific and Technical Information of China (English)

    李紫星; 于志勇; 廖洪峰

    2015-01-01

    通过对反渗透系统运行参数的分析,得出反渗透系统出力下降的主要原因是由于源水中有机物和微生物含量偏高,导致反渗透膜受到污染,反渗透膜中有机物和微生物污堵致使一段压差增大。制定了清洗前杀菌、碱洗、酸洗,清洗后杀菌的清洗方案,选择非氧化性杀菌剂,通过清洗,恢复了反渗透膜的性能。%By analyzing operating parameters of reverse osmosis system, the paper concludes that the output decrease of reverse osmosis system is due to high concentration of organic substances and microbes in source water, resulting in pollution of reverse osmosis membrane; block due to organic and microbe pollution in re-verse osmosis membrane caused increased pressure difference of section one. A cleaning plan comprising sterilization before cleaning, alkaline cleaning, acid cleaning and the sterilization after cleaning is worked out, which chooses non-oxidizing bactericide and recovers performance of reverse osmosis membrane by cleaning.

  5. Study of applicability of a reverse osmosis system in the treatment of waste liquids (RAD-WASTE); Estudio de aplicabilidad de un sistema de osmosis inversa en el tratamiento de residuos liquidos (RAD-WASTE)

    Energy Technology Data Exchange (ETDEWEB)

    Hortiguela Martinez, R.; Ruiz Garcia, P.; Saiz Cuesta, A.

    2013-07-01

    Study of alternatives to the current system of water treatment line of soils of the refueling (evaporation followed by a demineralization with ion exchange resins), with a technique more respectful with the environment as it is reverse osmosis. This process removed the soluble salts through semi-permeable membranes. These membranes are permeable to water but impermeable to most ions.

  6. Unilever chooses a reverse osmosis system to improve efficiency and save energy

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2006-11-15

    Rising energy prices have created new energy efficiency practices at Unilever's plant in Rexdale, Ontario. In order to meet an aggressive goal of reducing energy consumption by at least 6 per cent per year, the plant's energy team has implemented and documented 120 projects since 1999, saving more than $4.2 million in energy costs while eliminating 23,000 tonnes of greenhouse gases (GHGs). The team recently consulted with GE Water and Process Technologies to investigate efficiency measures for their steam plant operations. After analyzing the cost of purchasing and treating water used to produce the 218 million pounds of steam that the plant uses each year, GE recommended a reverse osmosis (RO) system to replace the water softeners and chloride anion de-alkalizers that treated the municipal water used throughout the plant. RO is a mechanical process involving the reversal of flow through a semi-permeable membrane from a high salinity solution to a high purity stream on the opposite side of the membrane. Pressure is used as the driving force for the separation. A turnkey system was installed at the plant in 2005, which also recycles process water captured throughout the plant for use as boiler make-up. The RO feed water allows the boilers to operate at 100 feedwater cycles instead of 10, dramatically increasing energy efficiency. By converting to the RO system, the plant is now consuming 13 million gallons less of municipal water and 8 per cent less natural gas, for a total savings of $68,000 and $299,000 respectively per year. The plant is also saving $11,700 in boiler chemicals and $22,000 in commodity softening chemicals. The RO system has also qualified the Rexdale plant for a $50,000 incentive grant from the City of Toronto for decreased water consumption. It was concluded that while the project has provided financial benefit to Unilever, the company is equally proud of the environmental benefits of the system, which both reduces chemical use and the

  7. Electrolysis-assisted mitigation of reverse solute flux in a three-chamber forward osmosis system.

    Science.gov (United States)

    Zou, Shiqiang; He, Zhen

    2017-05-15

    Forward osmosis (FO) has been widely studied for desalination or water recovery from wastewater, and one of its key challenges for practical applications is reverse solute flux (RSF). RSF can cause loss of draw solutes, salinity build-up and undesired contamination at the feed side. In this study, in-situ electrolysis was employed to mitigate RSF in a three-chamber FO system ("e-FO") with Na2SO4 as a draw solute and deionized (DI) water as a feed. Operation parameters including applied voltage, membrane orientation and initial draw concentrations were systematically investigated to optimize the e-FO performance and reduce RSF. Applying a voltage of 1.5 V achieved a RSF of 6.78 ± 0.55 mmol m(-2) h(-1) and a specific RSF of 0.138 ± 0.011 g L(-1) in the FO mode and with 1 M Na2SO4 as the draw, rendering ∼57% reduction of solute leakage compared to the control without the applied voltage. The reduced RSF should be attributed to constrained ion migration induced by the coactions of electric dragging force (≥1.5 V) and high solute rejection of the FO membrane. Reducing the intensity of the solution recirculation from 60 to 10 mL min(-1) significantly reduced specific energy consumption of the e-FO system from 0.693 ± 0.127 to 0.022 ± 0.004 kWh m(-3) extracted water or from 1.103 ± 0.059 to 0.044 ± 0.002 kWh kg(-1) reduced reversed solute. These results have demonstrated that the electrolysis-assisted RSF mitigation could be an energy-efficient method for controlling RSF towards sustainable FO applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Dialysis water treated by reverse osmosis decreases the levels of C-reactive protein in uremic patients

    Directory of Open Access Journals (Sweden)

    F.S. Thomé

    2005-05-01

    Full Text Available Atherosclerosis is a major complication of chronic renal failure. Microinflammation is involved in atherogenesis and is associated with uremia and dialysis. The role of dialysate water contamination in inducing inflammation has been debated. Our aim was to study inflammatory markers in patients on chronic dialysis, before and 3 to 6 months after switching the water purification system from deionization to reverse osmosis. Patients had demographic, clinical and nutritional information collected and blood drawn for determination of albumin, ferritin, C-reactive protein (CRP, interleukin-6, and tumor necrosis factor-alpha in both situations. Acceptable levels of water purity were less than 200 colony-forming units of bacteria and less than 1 ng/ml of endotoxin. Sixteen patients died. They had higher median CRP (26.6 vs 11.2 mg/dl, P = 0.007 and lower median albumin levels (3.1 vs 3.9 g/l, P < 0.05 compared to the 31 survivors. Eight patients were excluded because of obvious inflammatory conditions. From the 23 remaining patients (mean age ± SD: 51.3 ± 13.9 years, 18 had a decrease in CRP after the water treatment system was changed. Overall, median CRP was lower with reverse osmosis than with deionization (13.2 vs 4.5 mg/l, P = 0.022, N = 23. There was no difference in albumin, cytokines, subjective global evaluation, or clinical and biochemical parameters. In conclusion, uremic patients presented a clinically significant reduction in CRP levels when dialysate water purification system switched from deionization to reverse osmosis. It is possible that better water treatments induce less inflammation and eventually less atherosclerosis in hemodialysis patients.

  9. On the use of wind energy to power reverse osmosis desalination plant: A case study from Tenes (Algeria)

    Energy Technology Data Exchange (ETDEWEB)

    Dehmas, Djamila Abdeslame; Merzouk, Nachida Kasbadji [Wind Energy Division, Renewable Energy Development Center, BP. 62, Bouzareah, Algiers (Algeria); Kherba, Nabila; Hacene, Fouad Boukli [University Hassiba Ben Bouali of Chlef (Algeria); Merzouk, Mustapha [Mechanical Department, University Saad Dahlab of Blida (Algeria); Mahmoudi, Hacene [Wind Energy Division, Renewable Energy Development Center, BP. 62, Bouzareah, Algiers (Algeria); University Hassiba Ben Bouali of Chlef (Algeria); Goosen, Mattheus F.A. (Alfaisal University, P.O. Box 50927, Riyadh 11533, Saudi Arabia)

    2011-02-15

    The aim of this study was to provide a detailed analysis of wind energy resources for seawater reverse osmosis desalination (SWRO), in a case study region of Tenes Algeria, by using commercial Wasp software. An economic analysis of the environmental benefits was also done using RETScreen software to give details about financial investment hazards and CO{sub 2} emissions reduction. An energy yield and economical analysis was performed of a hypothetical wind farm consisting of 5 wind turbines of type Bonus 2 MW. It was found that wind energy can successfully power a SWRO desalination plant in the case study region. (author)

  10. Recovering/concentrating of hemicellulosic sugars and acetic acid by nanofiltration and reverse osmosis from prehydrolysis liquor of kraft based hardwood dissolving pulp process.

    Science.gov (United States)

    Ahsan, Laboni; Jahan, M Sarwar; Ni, Yonghao

    2014-03-01

    This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50g/L.

  11. 反渗透系统浓水回收利用方案介绍%Introduction of Concentrated Water Recycling Scheme in Reverse Osmosis System

    Institute of Scientific and Technical Information of China (English)

    韩华全

    2012-01-01

    The application of reverse osmosis system in painting industry and several condense water treatment of reverse osmosis system technology which used broadly in home and abroad were briefly introduced. The recycling using situation of the condense water in reverse osmosis system was introduced, the status was analyzed and the recycling using of the condense water was proposed too.%简要介绍反渗透技术在涂装行业的应用及国内外目前使用较多的几种反渗透系统浓水处置方法,说明当前反渗透系统浓水回收利用情况,分析并提出浓水回收利用方案。

  12. Application of Reverse Osmosis in Radioactive Wastewater Treatment%反渗透技术在放射性废水处理中的应用进展

    Institute of Scientific and Technical Information of China (English)

    孔劲松; 郭卫群

    2012-01-01

    Considering the disadvantages of the conventional evaporation and ion exchange process for radioactive wastewater treatment, the reverse osmosis is used to treat the low level radioactive wastewater. The paper summarizes the research and application progress of the reverse osmosis in the radioactive wastewater treatment and indicates that the reverse osmosis in the radioactive wastewater treatment is very important.%针对传统的蒸发和离子交换工艺处理放射性废水工作中存在的问题,提出采用反渗透分离技术处理低水平放射性废水,综述反渗透技术在放射性废水处理中的研究和应用进展,并指出反渗透技术在放射性废水处理中的重要性.

  13. Removal of toxic ions (chromate, arsenate, and perchlorate) using reverse osmosis, nanofiltration, and ultrafiltration membranes

    KAUST Repository

    Yoon, Jaekyung

    2009-09-01

    Rejection characteristics of chromate, arsenate, and perchlorate were examined for one reverse osmosis (RO, LFC-1), two nanofiltration (NF, ESNA, and MX07), and one ultrafiltration (UF and GM) membranes that are commercially available. A bench-scale cross-flow flat-sheet filtration system was employed to determine the toxic ion rejection and the membrane flux. Both model and natural waters were used to prepare chromate, arsenate, and perchlorate solutions (approximately 100 μg L-1 for each anion) in mixtures in the presence of other salts (KCl, K2SO4, and CaCl2); and at varying pH conditions (4, 6, 8, and 10) and solution conductivities (30, 60, and 115 mS m-1). The rejection of target ions by the membranes increases with increasing solution pH due to the increasingly negative membrane charge with synthetic model waters. Cr(VI), As(V), and ClO4 - rejection follows the order LFC-1 (>90%) > MX07 (25-95%) ≅ ESNA (30-90%) > GM (3-47%) at all pH conditions. In contrast, the rejection of target ions by the membranes decreases with increasing solution conductivity due to the decreasingly negative membrane charge. Cr(VI), As(V), and ClO4 - rejection follows the order CaCl2 < KCl ≅ K2SO4 at constant pH and conductivity conditions for the NF and UF membranes tested. For natural waters the LFC-1 RO membrane with a small pore size (0.34 nm) had a significantly greater rejection for those target anions (>90%) excluding NO3 - (71-74%) than the ESNA NF membrane (11-56%) with a relatively large pore size (0.44 nm), indicating that size exclusion is at least partially responsible for the rejection. The ratio of solute radius (ri,s) to effective membrane pore radius (rp) was employed to compare ion rejection. For all of the ions, the rejection is higher than 70% when the ri,s/rp ratio is greater than 0.4 for the LFC-1 membrane, while for di-valent ions (CrO4 2 -, SO4 2 -, and HAsSO4 2 -) the rejection (38-56%) is fairly proportional to the ri,s/rp ratio (0.32-0.62) for the ESNA

  14. Feasibility Analysis of a Seabed Filtration Intake System for the Shoaiba III Expansion Reverse Osmosis Plant

    KAUST Repository

    Rodríguez, Luis Raúl

    2012-06-01

    The ability to economically desalinate seawater in arid regions of the world has become a vital advancement to overcome the problem on freshwater availability, quality, and reliability. In contrast with the major capital and operational costs for desalination plants represented by conventional open ocean intakes, subsurface intakes allow the extraction of high quality feed water at minimum costs and reduced environmental impact. A seabed filter is a subsurface intake that consists of a submerged slow sand filter, with benefits of organic matter removal and pathogens, and low operational cost. A site investigation was carried out through the southern coast of the Red Sea in Saudi Arabia, from King Abdullah University of Science and Technology down to 370 kilometers south of Jeddah. A site adjacent to the Shoaiba desalination plant was selected to assess the viability of constructing a seabed filter. Grain sieve size analysis, porosity and hydraulic conductivity permeameter measurements were performed on the collected sediment samples. Based on these results, it was concluded that the characteristics at the Shoaiba site allow for the construction of a seabed filtration system. A seabed filter design is proposed for the 150,000 m3/d Shoaiba III expansion project, a large-scale Reverse Osmosis desalination plant. A filter design with a filtration rate of 7 m/d through an area of 6,000 m2 is proposed to meet the demand of one of the ten desalination trains operating at the plant. The filter would be located 90 meters offshore where hydraulic conductivity of the sediment is high, and mud percentage is minimal. The thin native marine sediment layer is insufficient to provide enough water filtration, and consequently the proposed solution involves excavating the limestone rock and filling it with different layers of non-native sand and gravel of increasing grain size. An initial assessment of the area around Shoaiba showed similar sedimentological conditions that could

  15. Effectiveness of seawater reverse osmosis (SWRO) pretreatment systems in removing transparent exopolymer particles (TEP) substances

    KAUST Repository

    Lee, Shang-Tse

    2015-05-01

    Transparent exopolymer particles (TEP) have been reported as one of the main factors of membrane fouling in seawater reverse osmosis (SWRO) process. Research has been focused on algal TEP so far, overlooking bacterial TEP. This thesis investigated the effects of coagulation on removal of bacterial TEP/TEP precursors in seawater and subsequent reduction on TEP fouling in ultrafiltration (UF), as a pretreatment of SWRO. Furthermore, the performance of pretreatment (coagulation + UF) has been investigated on a bench-scale SWRO system. TEP/TEP precursors were harvested from a strain of marine bacteria, Pseudoalteromonas atlantica, isolated from the Red Sea. Isolated bacterial organic matter (BOM), containing 1.5 mg xanthan gum eq./L TEP/TEP precursors, were dosed in Red Sea water to mimic a high TEP concentration event. Bacterial TEP/TEP precursors added to seawater were coagulated with ferric chloride and aluminum sulfate at different dosages and pH. Results showed that ferric chloride had a better removal efficiency on TEP/TEP precursors. Afterwards, the non-coagulated/coagulated seawater were tested on a UF system at a constant flux of 130 L/m2h, using two types of commercially available membranes, with pore sizes of 50 kDa and 100 kDa, respectively. The fouling potential of coagulated water was determined by the Modified Fouling Index (MFI-UF). Transmembrane pressure (TMP) was also continuously monitored to investigate the fouling development on UF membranes. TEP concentrations in samples were determined by the alcian blue staining assay. Liquid chromatography-organic carbon detection (LC-OCD) was used to determine the removal of TEP precursors with particular emphasis on biopolymers. Finally, SWRO tests showed that TEP/TEP precursors had a high fouling potential as indicated by MFI-UF, corresponding to the TMP measurements. Coagulation could substantially reduce TEP/TEP precursors fouling in UF when its dosage was equal or higher than 0.2 mg Fe/L. The flux decline

  16. Comparison of energy efficiency and power density in pressure retarded osmosis and reverse electrodialysis.

    Science.gov (United States)

    Yip, Ngai Yin; Elimelech, Menachem

    2014-09-16

    Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are emerging membrane-based technologies that can convert chemical energy in salinity gradients to useful work. The two processes have intrinsically different working principles: controlled mixing in PRO is achieved by water permeation across salt-rejecting membranes, whereas RED is driven by ion flux across charged membranes. This study compares the energy efficiency and power density performance of PRO and RED with simulated technologically available membranes for natural, anthropogenic, and engineered salinity gradients (seawater-river water, desalination brine-wastewater, and synthetic hypersaline solutions, respectively). The analysis shows that PRO can achieve both greater efficiencies (54-56%) and higher power densities (2.4-38 W/m(2)) than RED (18-38% and 0.77-1.2 W/m(2)). The superior efficiency is attributed to the ability of PRO membranes to more effectively utilize the salinity difference to drive water permeation and better suppress the detrimental leakage of salts. On the other hand, the low conductivity of currently available ion exchange membranes impedes RED ion flux and, thus, constrains the power density. Both technologies exhibit a trade-off between efficiency and power density: employing more permeable but less selective membranes can enhance the power density, but undesired entropy production due to uncontrolled mixing increases and some efficiency is sacrificed. When the concentration difference is increased (i.e., natural → anthropogenic → engineered salinity gradients), PRO osmotic pressure difference rises proportionally but not so for RED Nernst potential, which has logarithmic dependence on the solution concentration. Because of this inherently different characteristic, RED is unable to take advantage of larger salinity gradients, whereas PRO power density is considerably enhanced. Additionally, high solution concentrations suppress the Donnan exclusion effect of the

  17. 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.

  18. Recirculation of reverse osmosis concentrate in lab-scale anaerobic and aerobic landfill simulation reactors.

    Science.gov (United States)

    Morello, Luca; Cossu, Raffaello; Raga, Roberto; Pivato, Alberto; Lavagnolo, Maria Cristina

    2016-10-01

    Leachate treatment is a major issue in the context of landfill management, particularly in view of the consistent changes manifested over time in the quality and quantity of leachate produced, linked to both waste and landfill characteristics, which renders the procedure technically difficult and expensive. Leachate recirculation may afford a series of potential advantages, including improvement of leachate quality, enhancement of gas production, acceleration of biochemical processes, control of moisture content, as well as nutrients and microbe migration within the landfill. Recirculation of the products of leachate treatment, such as reverse osmosis (RO) concentrate, is a less common practice, with widespread controversy relating to its suitability, potential impacts on landfill management and future gaseous and leachable emissions. Scientific literature provides the results of only a few full-scale applications of concentrate recirculation. In some cases, an increase of COD and ammonium nitrogen in leachate was observed, coupled with an increase of salinity; which, additionally, might negatively affect performance of the RO plant itself. In other cases, not only did leachate production not increase significantly but the characteristics of leachate extracted from the well closest to the re-injection point also remained unchanged. This paper presents the results of lab-scale tests conducted in landfill simulation reactors, in which the effects of injection of municipal solid waste (MSW) landfill leachate RO concentrate were evaluated. Six reactors were managed with different weekly concentrate inputs, under both anaerobic and aerobic conditions, with the aim of investigating the short and long-term effects of this practice on landfill emissions. Lab-scale tests resulted in a more reliable identification of compound accumulation and kinetic changes than full-scale applications, further enhancing the development of a mass balance in which gaseous emissions and waste

  19. Characterization and effect of biofouling on polyamide reverse osmosis and nanofiltration membrane surfaces.

    Science.gov (United States)

    Khan, Mohiuddin Md Taimur; Stewart, Philip S; Moll, David J; Mickols, William E; Nelson, Sara E; Camper, Anne K

    2011-02-01

    Biofouling is a major reason for flux decline in the performance of membrane-based water and wastewater treatment plants. Initial biochemical characterization of biofilm formation potential and biofouling on two commercially available membrane surfaces from FilmTec Corporation were investigated without filtration in laboratory rotating disc reactor systems. These surfaces were polyamide aromatic thin-film reverse osmosis (RO) (BW30) and semi-aromatic nanofiltration (NF270) membranes. Membrane swatches were fixed on removable coupons and exposed to water with indigenous microorganisms supplemented with 1.5 mg l(-1) organic carbon under continuous flow. After biofilms formed, the membrane swatches were removed for analyses. Staining and epifluorescence microscopy revealed more cells on the RO than on the NF surface. Based on image analyses of 5-μm thick cryo-sections, the accumulation of hydrated biofoulants on the RO and NF surfaces exceeded 0.74 and 0.64 μm day(-1), respectively. As determined by contact angle the biofoulants increased the hydrophobicity up to 30° for RO and 4° for NF surfaces. The initial difference between virgin RO and NO hydrophobicities was ∼5°, which increased up to 25° after biofoulant formation. The initial roughness of RO and NF virgin surfaces (75.3 nm and 8.2 nm, respectively) increased to 48 nm and 39 nm after fouling. A wide range of changes of the chemical element mass percentages on membrane surfaces was observed with X-ray photoelectron spectroscopy. The initial chemical signature on the NF surface was better restored after cleaning than the RO membrane. All the data suggest that the semi-aromatic NF surface was more biofilm resistant than the aromatic RO surface. The morphology of the biofilm and the location of active and dead cell zones could be related to the membrane surface properties and general biofouling accumulation was associated with changes in the surface chemistry of the membranes, suggesting the validity of

  20. Desalination of mixed tannery effluent with membrane bioreactor and reverse osmosis treatment.

    Science.gov (United States)

    Scholz, W G; Rougé, P; Bódalo, A; Leitz, U

    2005-11-01

    A limiting factor for the reuse and recycling of treated tannery wastewater for irrigation and other uses is the high salt content, which persists even after conventional treatment. Reverse osmosis (RO) membrane treatment has been shown to significantly reduce the salt contents of tannery effluents. However, the high organic content of tannery effluent leads to rapid scaling and biofouling of RO membranes with a consequent reduction in flux rates and performance. Membrane bioreactors (MBR) have been shown to be highly effective in the removal of organic pollutants and suspended solids from tannery effluent. This research investigated the use of a combined MBR and RO treatment process to treat tannery effluents to an acceptable level for irrigation purposes. The MBR was operated at 17-20 h retention time, at a F/M ratio of 0.52 kg COD x kg SS(-1) x day(-1) and a volumetric loading rate of 3.28 kg COD x m(-3) x day(-1). This treatment reduced the COD, BOD, and ammonia concentrations of the effluent by 90-100%. The MBR was shown to be an excellent pretreatment prior to RO technology, due to the high removal efficiency of organic compounds and suspended solids, with average concentrations of 344 mg x L(-1) COD and 20 mg x L(-1) BOD achieved in the permeate. RO treatment reduced the salt content of the MBR permeate by up to 97.1%. The results of the research demonstrated that the MBR system developed was appropriate for the treatment of tannery effluents and, in combination with the RO treatment, reduced the salt content to acceptable levels for irrigation. The MBR pretreatment reduced bio-fouling and scaling of subsequent RO treatment and improved the overall performance of the RO unit. It is believed that this is the first investigation of a combined MBR and RO treatment for tannery effluents. This research provided data for an outline design of a full-scale MBR and RO plant with a treatment capacity of 5000 m3 per day for mixed tannery effluents.

  1. Organic Carbon Reduction in Seawater Reverse Osmosis (SWRO) Plants, Jeddah, Saudi Arabia

    KAUST Repository

    Alshahri, Abdullah

    2015-12-01

    Desalination is considered to be a major source of usable water in the Middle East, especially the Gulf countries which lack fresh water resources. A key and sometimes the only solution to produce high quality water in these countries is through the use of seawater reverse osmosis (SWRO) desalination technology. Membrane fouling is an economic and operational defect that impacts the performance of SWRO desalination technology. To limit this fouling phenomenon, it is important to implement the appropriate type of intake and pre-treatment system design. In this study, two types of systems were investigated, a vertical well system and a surface-water intake at a 9m depth. The purpose of this investigation is to study the impact of the different intake systems and pre-treatment stages in minimizing the concentrations of algae, bacteria, natural organic matter (NOM) and transparent exopolymer particles (TEP), in the feed water prior to pre-treatment, through the pre-treatment stages, and in the product water and concentrate. Water samples were collected from the surface seawater, the intakes (wells for site A, 9 m depth open ocean intake at site B), after the media filter, after the cartridge filter, and from the permeate and reject streams. The measured parameters included physical parameters, algae, bacteria, total organic carbon (TOC), fractions of dissolved NOM, particulate and colloidal TEP. The results of this study prove that the natural filtration and biological treatment of the seawater which occur in the aquifer matrix are very effective in improving the raw water quality to a significant degree. The results demonstrated that algae and biopolymers were 100% removed, the bacterial concentrations were significantly removed and roughly 50% or greater of TOC concentrations was eliminated by the aquifer matrix at site A. The aquifer feeding the vertical wells reduced TEP concentrations, but to differing degree. There is a slight decrease in the concentrations of

  2. Comparison of Energy Efficiency and Power Density in Pressure Retarded Osmosis and Reverse Electrodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Yip, NY; Elimelech, M

    2014-09-16

    Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are emerging membrane-based technologies that can convert chemical energy in salinity gradients to useful work. The two processes have intrinsically different working principles: controlled mixing in PRO is achieved by water permeation across salt-rejecting membranes, whereas RED is driven by ion flux across charged membranes. This study compares the energy efficiency and power density performance of PRO and RED with simulated technologically available membranes for natural, anthropogenic, and engineered salinity gradients (seawater-river water, desalination brine-wastewater, and synthetic hypersaline solutions, respectively). The analysis shows that PRO can achieve both greater efficiencies (54-56%) and higher power densities (2.4-38 W/m(2)) than RED (18-38% and 0.77-1.2 W/m(2)). The superior efficiency is attributed to the ability of PRO membranes to more effectively utilize the salinity difference to drive water permeation and better suppress the detrimental leakage of salts. On the other hand, the low conductivity of currently available ion exchange membranes impedes RED ion flux and, thus, constrains the power density. Both technologies exhibit a trade-off between efficiency and power density: employing more permeable but less selective membranes can enhance the power density, but undesired entropy production due to uncontrolled mixing increases and some efficiency is sacrificed. When the concentration difference is increased (i.e., natural -> anthropogenic -> engineered salinity gradients), PRO osmotic pressure difference rises proportionally but not so for RED Nernst potential, which has logarithmic dependence on the solution concentration. Because of this inherently different characteristic, RED is unable to take advantage of larger salinity gradients, whereas PRO power density is considerably enhanced. Additionally, high solution concentrations suppress the Donnan exclusion effect of the

  3. Fouling of Seawater Reverse Osmosis (SWRO) Membrane: Chemical and Microbiological Characterization

    KAUST Repository

    Khan, Muhammad T.

    2013-12-01

    In spite of abundant water resources, world is suffering from the scarcity of usable water. Seawater Reverse Osmosis (SWRO) desalination technology using polymeric membranes has been recognized as a key solution to water scarcity problem. However, economic sustainability of this advanced technology is adversely impacted by the membrane fouling problem. Fouling of RO membranes is a highly studied phenomenon. However, literature is found to be lacking a detailed study on kinetic and dynamic aspects of SWRO membrane fouling. The factors that impact the fouling dynamics, i.e., pretreatment and water quality were also not adequately studied at full–scale of operation. Our experimental protocol was designed to systematically explore these fouling aspects with the objective to improve the understanding of SWRO membrane fouling mechanisms. An approach with multiple analytical techniques was developed for fouling characterization. In addition to the fouling layer characterization, feed water quality was also analysed to assess its fouling potential. Study of SWRO membrane fouling dynamics and kinetics revealed variations in relative abundance of chemical and microbial constituents of the fouling layer, over operating time. Aromatic substances, most likely humic–like substances, were observed at relatively high abundance in the initial fouling layer, followed by progressive increase in relative abundances of proteins and polysaccharides. Microbial population grown on all membranes was dominated by specific groups/species belonging to different classes of Proteobacteria phylum; however, similar to abiotic foulant, their relative abundance also changed with the biofilm age and with the position of membrane element in RO vessel. Our results demonstrated that source water quality can significantly impact the RO membrane fouling scenarios. Moreover, the major role of chlorination in the SWRO membrane fouling was highlighted. It was found that intermittent mode of chlorination

  4. 100t/h反渗透膜化学清洗总结%A summary of 100 t/h chemical cleaning of reverse osmosis membrane

    Institute of Scientific and Technical Information of China (English)

    毛建新

    2012-01-01

    针对脱盐水装置反渗透膜运行一段时间后出现的因细菌繁殖、结垢造成浓水侧堵塞,产水量下降,进水压力升高等问题,对反渗透膜进行了化学清洗。%This paper focuses on chemical cleaning reverse osmosis membrane, to deal with the problems such as water production decreased, inlet pressure due to bacterial reproduction, fouling caused by concentrated water side plug for a period after the process of water desalination unit operation of reverse osmosis.

  5. Application of Reverse Osmosis Technology in Boron Wastewater Treatment%反渗透技术在含硼废水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    梁松筠

    2015-01-01

    This article discusses the principle of reverse osmosis technology in boron wastewater treatment, and simulation test of the removal effect of boron.The experimental results show that under suitable conditions , boron removal rate of reverse osmosis technology can reach 93%.%本文简单论述了反渗透技术处理含硼废水原理,并对硼的去除效果进行了模拟试验。实验结果表明:在适宜条件下,反渗透技术对硼的去除率可达到93%。

  6. Integrated removal of inorganic contaminants from acid mine drainage using BOF slag, lime, soda ash and reverse osmosis (RO): Implication for the production of drinking water

    CSIR Research Space (South Africa)

    Masindi, Vhahangwele

    2017-06-01

    Full Text Available , Finland IMWA 2017Mine Water and Circular Economy Wolkersdorfer C, Sartz L, Sillanpää M, Häkkinen A (Editors) Integrated removal of inorganic contaminants from Acid Mine Drainage using BOF Slag, Lime, Soda ash and Reverse Osmosis (RO): Implication... was reduced from 18000 to 4000 mg/L hence requiring another purification technology. Hardness was reduced using lime and soda ash. Reverse Osmosis (RO) was used to further clean the water to drinking standard. A single pass two element RO system...

  7. Basic aspects of the use of reverse osmosis in indirect potable reuse; Aspectos basicos de la aplicacion de la osmosis inversa a la reutilizacion potable indirecta

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Ramirez, J. A.; Sales Marquez, D.; Quiroga Alonso, J. M.; Asano, T.

    2003-07-01

    Wastewater reclamation and reuse is an increasing activity in those countries who are facing water restrictions both in quality and quantity, and it has become an integral part of water resources management. Among several applications of reclaimed wastewater, one of the most interesting and innovative is indirect potable reuse. This consists in the purposeful augmentation of surface or groundwater resources with highly treated reclaimed water which will ultimately serve as a source of drinking water. There are world-wide experiences confirming that this kind of application is safe. The use of reverse osmosis for wastewater reclamation is very interesting and the use of this in indirect potable reuse started more that thirty years ago, mainly in USA. However the extension of this kind of applications is in someway low, not for economic issues or technology faults,but the ignorance, distrust or public opinion rejection. In this paper, the most important challenges, from a technical and scientific point of view, of indirect potable reuse are discussed to allow it to be used as a safe, reliable and additional water source: with all its implications and, of course, with all its benefits. (Author) 16 refs.

  8. Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane

    Directory of Open Access Journals (Sweden)

    Amine Mnif

    2017-01-01

    Full Text Available Nanofiltration and reverse osmosis are investigated as a possible alternative to the conventional methods of Cr(VI removal from model water and industrial effluent. The influences of feed concentration, water recovery, pH, and the coexisting anions were studied. The results have shown that retention rates of hexavalent chromium can reach 99.7% using nanofiltration membrane (NF-HL and vary from 85 to 99.9% using reverse osmosis membrane (RO-SG depending upon the composition of the solution and operating conditions. This work was also extended to investigate the separation of Cr(VI from car shock absorber factory effluent. The use of these membranes is very promising for Cr(VI water treatment and desalting industry effluent. Spiegler-Kedem model was applied to experimental results in the aim to determine phenomenological parameters, the reflection coefficient of the membrane (σ, and the solute permeability coefficient (Ps. The convective and diffusive parts of the mass transfer were quantified with predominance of the diffusive contribution.

  9. Hexavalent Chromium Removal from Model Water and Car Shock Absorber Factory Effluent by Nanofiltration and Reverse Osmosis Membrane

    Science.gov (United States)

    Bejaoui, Imen; Mouelhi, Meral; Hamrouni, Béchir

    2017-01-01

    Nanofiltration and reverse osmosis are investigated as a possible alternative to the conventional methods of Cr(VI) removal from model water and industrial effluent. The influences of feed concentration, water recovery, pH, and the coexisting anions were studied. The results have shown that retention rates of hexavalent chromium can reach 99.7% using nanofiltration membrane (NF-HL) and vary from 85 to 99.9% using reverse osmosis membrane (RO-SG) depending upon the composition of the solution and operating conditions. This work was also extended to investigate the separation of Cr(VI) from car shock absorber factory effluent. The use of these membranes is very promising for Cr(VI) water treatment and desalting industry effluent. Spiegler-Kedem model was applied to experimental results in the aim to determine phenomenological parameters, the reflection coefficient of the membrane (σ), and the solute permeability coefficient (Ps). The convective and diffusive parts of the mass transfer were quantified with predominance of the diffusive contribution. PMID:28819360

  10. Surface modification of commercial seawater reverse osmosis membranes by grafting of hydrophilic monomer blended with carboxylated multiwalled carbon nanotubes

    Science.gov (United States)

    Vatanpour, Vahid; Zoqi, Naser

    2017-02-01

    In this study, modification of commercial seawater reverse osmosis membranes was carried out with simultaneous use of surface grafting and nanoparticle incorporation. Membrane grafting with a hydrophilic acrylic acid monomer and thermal initiator was used to increase membrane surface hydrophilicity. The used nanomaterial was carboxylated multiwalled carbon nanotubes (MWCNTs), which were dispersed in the grafting solution and deposited on membrane surface to reduce fouling by creating polymer brushes and hydrodynamic resistance. Effectiveness of the grafting process (formation of graft layer on membrane surface) was proved by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Increase of membrane surface hydrophilicity was approved with contact angle test. First, the grafting was performed on the membrane surfaces with different monomer concentrations, various contact times and several membrane curing times (three variables for optimization). The modified membranes were tested by a cross-flow setup using saline solution for permeability and rejection tests, and bovine serum albumin (BSA) solution for fouling test. The results showed that the modified membranes with 0.75 M of monomer, 3 min contact time and 80 min curing time in an oven at 50 °C presented the highest flux and lowest rejection decline related to the commercial reverse osmosis membrane. In the next step, the optimum grafting condition was selected and the nanotubes with different weight percentages were dispersed in the acrylic acid monomer solution. The membrane containing 0.25 wt% COOH-MWCNTs showed the highest fouling resistance.

  11. Changes in the components and biotoxicity of dissolved organic matter in a municipal wastewater reclamation reverse osmosis system.

    Science.gov (United States)

    Sun, Ying-Xue; Hu, Hong-Ying; Shi, Chun-Zhen; Yang, Zhe; Tang, Fang

    2016-09-01

    The characteristics of dissolved organic matter (DOM) and the biotoxicity of these components were investigated in a municipal wastewater reclamation reverse osmosis (mWRRO) system with a microfiltration (MF) pretreatment unit. The MF pretreatment step had little effect on the levels of dissolved organic carbon (DOC) in the secondary effluent, but the addition of chlorine before MF promoted the formation of organics with anti-estrogenic activity. The distribution of excitation emission matrix (EEM) fluorescence constituents exhibited obvious discrepancies between the secondary effluent and the reverse osmosis (RO) concentrate. Using size exclusion chromatography, DOM with low molecular weights of approximately 1.2 and 0.98 kDa was newly formed during the mWRRO. The normalized genotoxicity and anti-estrogenic activity of the RO concentrate were 32.1 ± 10.2 μg4-NQO/mgDOC and 0.36 ± 0.08 mgTAM/mgDOC, respectively, and these values were clearly higher than those of the secondary effluent and MF permeate. The florescence volume of Regions I and II in the EEM spectrum could be suggested as a surrogate for assessing the genotoxicity and anti-estrogenic activity of the RO concentrate.

  12. Technical-Economic Analysis of Photovoltaik Reverse Osmosis Planning for Fulfillment of Fresh Water System on Ro-Pax Ship

    Directory of Open Access Journals (Sweden)

    Edi Jadmiko

    2017-09-01

    Full Text Available The need for fresh water in the world of industry is increasing with the rapid development of the global industry. The shipping industry is having a significant impact as part of a global industry concerning the sector of freshwater demand on ships. Freshwater supplies on ro-pax vessels are very important because they are the source of crew and passenger life when ships sail. Fulfillment of freshwater needs on a ro-pax vessel is made in a conventional system by filling clean water into a freshwater tank from the port. In this final project will be analyzed technical and economical on designing fresh water system using reverse osmosis system with solar panel as power supply and compare it with conventional system on ship KM. SABUK NUSANTARA 56. This Final Project includes installation design, size of fresh water tank, amount of cargo, investment cost and operational cost. The conclusion obtained in this final project is a reverse osmosis (RO system with solar panels as a very efficient power supply when applied to ro-pax ships such as ships KM SABUK NUSANTARA 56 because with this system the ship is able to produce their own fresh water, the size of the freshwater tank is smaller, for new shiploads can be increased. For the percentage of total cost of fresh water needs is dearer about 52 percent compared to conventional system and payload value increased 29.2 percent compared to conventional system.

  13. 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.

  14. Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ozaydin-Ince, Gozde, E-mail: gozdeince@sabanciuniv.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Matin, Asif, E-mail: amatin@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khan, Zafarullah, E-mail: zukhan@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Zaidi, S.M. Javaid, E-mail: zaidismj@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gleason, Karen K., E-mail: kkgleasn@mit.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-07-31

    Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. - Highlights: • Thin films are deposited on reverse osmosis membranes. • Amphiphilic thin films are resistant to protein attachment. • The permeation performance of the membranes is not affected by the coating. • The thin film coatings delayed the biofouling.

  15. Learning about (Not by) Osmosis.

    Science.gov (United States)

    Borovoy, Alexander

    1991-01-01

    Describes the process of osmosis from its discovery by Nollet in 1848 to modern applications. Uses experimental descriptions, illustrations, and photographs to explain osmosis. Discusses the technology of producing perfect filters and their applications in reverse osmosis to purify salt water and to filter blood in kidney machines. (PR)

  16. Efficiently Combining Water Reuse and Desalination through Forward Osmosis—Reverse Osmosis (FO-RO) Hybrids: A Critical Review

    Science.gov (United States)

    Blandin, Gaetan; Verliefde, Arne R.D.; Comas, Joaquim; Rodriguez-Roda, Ignasi; Le-Clech, Pierre

    2016-01-01

    Forward osmosis (FO) is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO) hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application) and water management challenges (proximity of wastewater and desalination plants), FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO) demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs) in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling. PMID:27376337

  17. Efficiently Combining Water Reuse and Desalination through Forward Osmosis—Reverse Osmosis (FO-RO Hybrids: A Critical Review

    Directory of Open Access Journals (Sweden)

    Gaetan Blandin

    2016-07-01

    Full Text Available Forward osmosis (FO is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application and water management challenges (proximity of wastewater and desalination plants, FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling.

  18. Ceramic membrane as a pretreatment for reverse osmosis: Interaction between marine organic matter and metal oxides

    KAUST Repository

    Dramas, Laure

    2013-02-01

    Scaling and (bio)fouling phenomena can severely alter the performance of the reverse osmosis process during desalination of seawater. Pretreatments must be applied to efficiently remove particles, colloids, and also precursors of the organic fouling and biofouling. Ceramic membranes offer a lot of advantages for micro and ultrafiltration pretreatments because their initial properties can be recovered using more severe cleaning procedure. The study focuses on the interaction between metal oxides and marine organic matter. Experiments were performed at laboratory scale. The first series of experiments focus on the filtration of different fractions of natural organic matter and model compounds solutions on flat disk ceramic membranes (47 mm of diameter) characterized with different pore size and composition. Direct filtration experiments were conducted at 0.7 bar or 2 bars and at room temperature (20 ± 0.5 °C). The efficiency of backflush and alkaline cleaning were eval, and titanium oxides. Each metal oxide corresponds to a specific pore size for the disk ceramic membranes: 80, 60, and 30 nm. Different sizes of metal oxide particles are used to measure the impact of the surface area on the adsorption of the organic matter. Seawaters from the Arabian Gulf and from the Red Sea were collected during algal blooms. Cultures of algae were also performed in the laboratory and in cooperation with woods hole oceanographic institute. Solutions of algal exudates were obtained after a couple of weeks of cultivation followed by sonication. Solutions were successively filtered through GFF (0.7 lm) and 0.45 lm membrane filters before use. The dissolved organic carbon (DOC) concentration of final solution was between 1 and 4 mg/L and showed strong hydrophilic character. These various solutions were prepared with the objective to mimic the dissolved organic matter composition of seawater subjected to algal bloom. Characterization of the solutions of filtration experiments (feed

  19. Impact of Acid Cleaning on the Performance of PVDF UF Membranes in Seawater Reverse Osmosis Pretreatment

    KAUST Repository

    Alsogair, Safiya

    2016-05-05

    Low-pressure membrane systems such as Microfiltration (MF) and Ultrafiltration (UF) have been presented as viable option to pre-treatment systems in potable water applications. UF membranes are sporadically backwashed with ultra-filtered water to remove deposited matter from the membrane and restore it. Several factors that may cause permeability and selectivity decrease are involved and numerous procedures are applicable to achieve this objective. Membrane cleaning is the most important step required to maintain the characteristics of the membrane. This research was made with the purpose of investigating the effects of acid cleaning during chemically enhanced backwashing (CEB) on the performance of ultrafiltration (UF) membranes in seawater reverse osmosis (SWRO) pretreatment. To accomplish this, the questions made were: Does the acid addition (before or after the alkali CEB) influence the overall CEB cleaning effectiveness on Dow UF membrane? Does the CEB order of alkali (NaOCl) and acid (H2SO4) affect the overall CEB cleaning effectiveness? If yes, which order is better/worse? What is the optimal acid CEB frequency that will ensure the most reliable performance of the UF?. To answer this queries, a series of sequences were carried out with different types of chemical treatments: Only NaOCl, daily NaOCl plus weekly acid, daily NaOCl plus daily acid, and weekly acid plus daily NaOCl. To investigate the consequence of acid by studying the effect of operational data like the trans-pressure membrane, resistance or permeability and support that by the analytical experiments (organic, inorganic and microbial characterization). Microorganisms were removed almost completely at hydraulic cleaning and showed no difference with addition of acid. As a conclusion of the operational data the organic and inorganic chatacterization resulted in the elimination of the first sequence due to the acummulation of fouling over time, which produces that the cleaning increases downtime

  20. Attachment of antimicrobial peptides to reverse osmosis membranes by Cu(i)-catalyzed 1,3-dipolar alkyne-azide cycloaddition

    NARCIS (Netherlands)

    Bodner, Elias J.; Kandiyote, Nitzan Shtreimer; Lutskiy, Marina Yamit; Albada, Bauke; Metzler-Nolte, Nils; Uhl, Wolfgang; Kasher, Roni; Arnusch, Christopher J.

    2016-01-01

    Biofilms are detrimental to many industrial systems that include reverse osmosis (RO) membranes. Accordingly, the development of surfaces with inherently bactericidal properties has attracted much research attention. Antimicrobial peptides (AMPs) have been shown to be potent antimicrobial and ant

  1. APPLICATION CHARACTERISTICS OF REVERSE OSMOSIS DESALINATION MEMBRANE%反渗透海水淡化膜的应用特性

    Institute of Scientific and Technical Information of China (English)

    薛立波; 徐子丹; 王琪; 余涛

    2012-01-01

    综述了国内外反渗透海水淡化技术的研究发展过程及应用状况,重点介绍了中空纤维和卷式反渗透膜在海水淡化中的应用特性.比较了中空纤维和卷式反渗透膜的结构,性能及应用对象差异,展望了中空纤维反渗透膜将扩大海水淡化市场份额的应用前景.%The progress of reverse osmosis desalination technology and application of home and abroad were reviewed, highlighting the characteristics of the hollow fiber and spiral-wound reverse osmosis membrane desalination. The membrane structure, performance and application object differences of the hollow fiber and spiral wound reverse osmosis were compared, the prospect of hollow fiber reverse osmosis membrane which will expand the desalination market share prospects was reviewed.

  2. Research on Reverse Osmosis Ultrafiltration of Lentinus Polysaccharides%香菇多糖反渗透浓缩工艺的研究

    Institute of Scientific and Technical Information of China (English)

    孔静; 游丽君; 彭川丛; 赵谋明; 马方励

    2011-01-01

    采用反渗透膜浓缩工艺对香菇多糖提取液进行浓缩,分析进膜压力、料液浓度和进膜温度对浓缩工艺的影响,并比较了反渗透浓缩和真空浓缩两种方法的差异.结果表明,在进膜压力20 MPa、多糖浓度6.48 mg/mL、进膜温度30℃时能取得较好的浓缩效果.反渗透膜浓缩粗多糖得率较真空浓缩高,且DPPH自由基清除能力优于真空浓缩的产品.%Reverse osmosis ultrafiltration process was used in this paper to concentrate the lentinus extraction Effects of pressure,concentration and temperature on the speed of reverse osmosis were studied. Results showed that the highest lentinus polysaccharides concentration of 6.48mg/mL can be obtained by using reverse osmosis under the conditions of 20MPa and 30℃. Compared with vacuum concentration methods,the reverse osmosis methods showed both higher yield of polysaccharide and DPPH radical scavenging activity.

  3. 新型反渗透膜的研究进展%Advancement on the preparation of novel reverse osmosis membrane

    Institute of Scientific and Technical Information of China (English)

    陈欢林; 瞿新营; 张林; 高从堦

    2011-01-01

    反渗透膜的发展推动了水处理技术的进步,自从聚酰胺膜诞生,反渗透膜的发展处于瓶颈阶段,而寻求新型膜材料的研究也在进行中.文章从无机膜、杂化膜及新型有机膜三个方向叙述了近年来反渗透膜的研究状况,归纳了各种类型反渗透膜的分离性能,应用前景及存在问题,为反渗透膜的发展提供了参考依据.%The development of water treatment technology was propelled by the advancement of reverse osmosis membrane, and the bottleneck period of reverse osmosis membrane was started since the polyamide membrane was used. The advancement of reverse osmosis membrane on inorganic membrane, hybrid membrane and novel organic membrane was presented in this paper. The separation performance, the application status and problem was also summarized, and the guide for the development of reverse osmosis membrane was provided.

  4. Chemical Cleaning Analysis of Concentrated Water Reverse Osmosis Membrane%浓水反渗透膜元件化学清洗分析

    Institute of Scientific and Technical Information of China (English)

    冀美萍; 沈洪洋; 郭伟

    2011-01-01

    RO membrane fouling can cause system performance degradation, component of pressure difference between inlet and outlet, the increase of membrane components replacement. Periodic cleaning for the membrane is effective way to ensure the normal system operation and extend service life of elements of. Through analysis to the reason of concentrated reverse osmosis water system pollution, this article introduces the cleaning of reverse osmosis membrane method, and through two chemical cleaning data of dense water reverse osmosis system, it puts forward the optimal operation measures for concentrated water reverse osmosis system.%反渗透膜的污染会造成系统性能的下降、组件进出口压差的升高、膜元件的更换等。对膜进行定期的清洗是保证反渗透系统的正常运行、延长膜元件使用寿命的有效途径。通过对浓水反渗透系统污染原因的解读分析,讨论了反渗透膜清洗的方法,通过对浓水反渗透系统两次化学清洗数据进行对比分析,提出浓水反渗透系统优化运行的相关措施。

  5. Molecular characterization of the bacterial communities in the different compartments of a full-scale reverse-osmosis water purification plant

    NARCIS (Netherlands)

    Bereschenko, L.A.; Heilig, G.H.J.; Nederlof, M.M.; Loosdracht, van M.C.M.; Stams, A.J.M.; Euverink, G.J.W.

    2008-01-01

    The origin, structure, and composition of biofilms in various compartments of an industrial full-scale reverse-osmosis (RO) membrane water purification plant were analyzed by molecular biological methods. Samples were taken when the RO installation suffered from a substantial pressure drop and decre

  6. Molecular Characterization of the Bacterial Communities in the Different Compartments of a Full-Scale Reverse-Osmosis Water Purification Plant

    NARCIS (Netherlands)

    Bereschenko, L.A.; Heilig, G.H.J.; Nederlof, M.M.; Loosdrecht, M.C.M. van; Stams, A.J.M.; Euverink, G.J.W.

    2008-01-01

    The origin, structure, and composition of biofilms in various compartments of an industrial full-scale reverse-osmosis (RO) membrane water purification plant were analyzed by molecular biological methods. Samples were taken when the RO installation suffered from a substantial pressure drop and decre

  7. CHEMICAL ANALYSIS OF REVERSE OSMOSIS MEMBRANE AND XAD RESIN ADSORPTION CONCENTRATES OF WATER DISINFECTED BY CHLORINATION OR OZONATION/CHLORINATION PROCESSES

    Science.gov (United States)

    Chemical Analysis of Reverse Osmosis Membrane and XAD Resin Adsorption Concentrates of Water Disinfected by Chlorination or Ozonation/Chlorination Processes.J. E. Simmons1, S.D. Richardson2, K.M. Schenck3, T. F. Speth3, R. J. Miltner3 and A. D. Thruston21 NHEE...

  8. Spray Layer-by-Layer Assembled Clay Composite Thin Films as Selective Layers in Reverse Osmosis Membranes.

    Science.gov (United States)

    Kovacs, Jason R; Liu, Chaoyang; Hammond, Paula T

    2015-06-24

    Spray layer-by-layer assembled thin films containing laponite (LAP) clay exhibit effective salt barrier and water permeability properties when applied as selective layers in reverse osmosis (RO) membranes. Negatively charged LAP platelets were layered with poly(diallyldimethylammonium) (PDAC), poly(allylamine) (PAH), and poly(acrylic acid) (PAA) in bilayer and tetralayer film architectures to generate uniform films on the order of 100 nm thick that bridge a porous poly(ether sulfone) support to form novel RO membranes. Nanostructures were formed of clay layers intercalated in a polymeric matrix that introduced size-exclusion transport mechanisms into the selective layer. Thermal cross-linking of the polymeric matrix was used to increase the mechanical stability of the films and improve salt rejection by constraining swelling during operation. Maximum salt rejection of 89% was observed for the tetralayer film architecture, with an order of magnitude increase in water permeability compared to commercially available TFC-HR membranes. These clay composite thin films could serve as a high-flux alternative to current polymeric RO membranes for wastewater and brackish water treatment as well as potentially for forward osmosis applications. In general, we illustrate that by investigating the composite systems accessed using alternating layer-by-layer assembly in conjunction with complementary covalent cross-linking, it is possible to design thin film membranes with tunable transport properties for water purification applications.

  9. Pilot-Scale Investigation of Forward/Reverse Osmosis Hybrid System for Seawater Desalination Using Impaired Water from Steel Industry

    Directory of Open Access Journals (Sweden)

    Hanaa M. Ali

    2016-01-01

    Full Text Available This paper was focused on the investigation of a forward osmosis- (FO- reverse osmosis (RO hybrid process to cotreat seawater and impaired water from steel industry. By using this hybrid process, seawater can be diluted before desalination, hence reducing the energy cost of desalination, and simultaneously contaminants present in the impaired water are prevented from migrating into the product water through the FO and RO membranes. The main objective of this work was to investigate on pilot-scale system the performance of the combined FO pretreatment and RO desalination hybrid system and specifically its effects on membrane fouling and overall solute rejection. Firstly, optimization of the pilot-scale FO process to obtain the most suitable and stable operating conditions for practical application was investigated. Secondly, pilot-scale RO process performance as a posttreatment to FO process was evaluated in terms of water flux and rejection. The results indicated that the salinity of seawater reduced from 35000 to 13000 mg/L after 3 hrs using FO system, while after 6 hrs it approached 10000 mg/L. Finally, FO/RO system was tested on continuous operation for 15 hrs and it was demonstrated that no pollutant was detected neither in draw solution nor in RO permeate after the end of operating time.

  10. A Pilot-scale Study on Coal Gasification Wastewater Reclamation Using Pretreatment Alternatives Combined with Ultrafiltration and Reverse Osmosis

    Institute of Scientific and Technical Information of China (English)

    Qian Zhao; Hongjun Han; Fang Fang; Peng Xu; Kun Li; Dexin Wang

    2015-01-01

    Aims to investigate the performance of the pilot⁃scale reclamation plant for coal gasification wastewater ( CGW) using ultrafiltration and reverse osmosis with appropriate pretreatment alternatives, different pre⁃treatment alternatives⁃coagulation, adsorption, and ozonation methods were employed to treat the secondary effluent of coal gasification wastewater ( SECGW ) in a pilot⁃scale pressurized membrane system. The performance was compared to choose the most suitable pre⁃treatment alternative for the SECGW reclamation. Ozone reaction achieved highest COD removal efficiency (79.6%-91.0%), resulting in the stable normalized parameters of the subsequent ultrafiltration and reverse osmoses. In contrast, the coagulation and adsorption processes achieved only 32. 8%-45. 7% and 53. 1%-64. 6% decreases in COD, respectively. The residual organic pollutants in the reverse osmosis feed water led to an increase in normalized pressure drop and a decrease in normalized permeability ( or membrane transference coefficient) . The hydrophobic fraction was the main constituent ( approx. 70% of DOC ) in pretreated SECGW, and the hydrophobic⁃neutral fraction contributed mostly to the UV absorbance ( 53%) . Fluorescence excitation emission matrices revealed that ozonation removed most of the hydrophobic and aromatic proteins such as tyrosine and tryptophan which dominated in raw wastewater. The recalcitrant compounds such as phenolic compounds, heterocyclic compounds, especially long⁃chain hydrocarbons, which were easily attached to the membrane surface and contributed to organic fouling, could be oxidized and mineralized by ozone. Among the three pretreatments, ozonation showed highest removal efficiencies of hydrophobic and aromatic proteins, therefore resulting in highest normalized permeability.

  11. Fuzzy logic: applications to the pretreatment of brackish feed water in reverse osmosis treatment plants; Logica difusa: aplicaciones al pretratamiento del agua salobre de elimentacion de plantas desalladoras por osmosis inversa

    Energy Technology Data Exchange (ETDEWEB)

    Pluss Contino, J.; Simon Ruiz, J. L.; Hernandez, A.; Menendez Martinez, A.; Yaglian Steiner, E.; Menendez Fernandez, A.; Marcelo Cano, F.

    2004-07-01

    Frequently physical and chemical alteration that can suffer feed water composition and membranes behaviour of reverse osmosis desalination plants (RODP), define a vague nature system from the point of view of decision make process. In this work, we proposes the utilization of the approximate reasoning associated with the fuzzy logic, as an alternative to approach this problem and to make possible early corrective actions, that is, to do a proactive maintenance with Condition-based maintenance (CBM) technology. (Author) 21 refs.

  12. Conceptual design and cost study for a dual-purpose nuclear-electric reverse osmosis seawater conversion plant

    Energy Technology Data Exchange (ETDEWEB)

    1979-04-01

    The objective of this study was to develop a conceptual design and cost estimate for a 25 million gallon per day seawater reverse osmosis desalting plant operating at both Caribbean and Persian Gulf sites. The plant would operate in conjunction with a 1000 MW(e) nuclear power plant. Four seawater membrane manufacturers were supplied with feedwater analysis and a simplified cost estimating procedure in order to recommend membrane systems which would be applicable. For both sites a two-stage system was selected for development of a conceptual cost estimate. The product water cost was found to be (based upon 1978 United States construction costs) $3.17/1000 gallons for the Caribbean site and $3.75/1000 gallons for the Persian Gulf site.

  13. Reverse osmosis membrane composition, structure and performance modification by bisulphite, iron(III), bromide and chlorite exposure.

    Science.gov (United States)

    Ferrer, O; Gibert, O; Cortina, J L

    2016-10-15

    Reverse osmosis (RO) membrane exposure to bisulphite, chlorite, bromide and iron(III) was assessed in terms of membrane composition, structure and performance. Membrane composition was determined by Rutherford backscattering spectrometry (RBS) and membrane performance was assessed by water and chloride permeation, using a modified version of the solution-diffusion model. Iron(III) dosage in presence of bisulphite led to an autooxidation of the latter, probably generating free radicals which damaged the membrane. It comprised a significant raise in chloride passage (chloride permeation coefficient increased 5.3-5.1 fold compared to the virgin membrane under the conditions studied) rapidly. No major differences in terms of water permeability and membrane composition were observed. Nevertheless, an increase in the size of the network pores, and a raise in the fraction of aggregate pores of the polyamide (PA) layer were identified, but no amide bond cleavage was observed. These structural changes were therefore, in accordance with the transport properties observed.

  14. A new flat sheet membrane bioreactor hybrid system for advanced treatment of effluent, reverse osmosis pretreatment and fouling mitigation.

    Science.gov (United States)

    Hosseinzadeh, Majid; Bidhendi, Gholamreza Nabi; Torabian, Ali; Mehrdadi, Naser; Pourabdullah, Mehdi

    2015-09-01

    This paper introduces a new hybrid electro membrane bioreactor (HEMBR) for reverse osmosis (RO) pretreatment and advanced treatment of effluent by simultaneously integrating electrical coagulation (EC) with a membrane bioreactor (MBR) and its performance was compared with conventional MBR. Experimental results and their statistical analysis showed removal efficiency for suspended solids (SS) of almost 100% for both reactors. HEMBR removal of chemical oxygen demand (COD) improved by 4% and membrane fouling was alleviated according to transmembrane pressure (TMP). The average silt density index (SDI) of HEMBR permeate samples was slightly better indicating less RO membrane fouling. Moreover, based on the SVI comparison of two reactor biomass samples, HEMBR showed better settling characteristics which improved the dewaterability and filterability of the sludge. Analysis the change of membrane surfaces and the cake layer formed over them through field emission scanning electron microscopy (FESEM) and X-ray fluorescence spectrometer (XRF) were also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite

    Science.gov (United States)

    Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

    2015-09-01

    Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes.

  16. Application of immersed MF (IMF) followed by reverse osmosis (RO) membrane for wastewater reclamation: A case study in Malaysia.

    Science.gov (United States)

    Ujang, Z; Ng, K S; Tg Hamzah, Tg Hazmin; Roger, P; Ismail, M R; Shahabudin, S M; Abdul Hamid, M H

    2007-01-01

    A pilot scale membrane plant was constructed and monitored in Shah Alam, Malaysia for municipal wastewater reclamation for industrial application purposes. The aim of this study was to verify its suitability under the local conditions and environmental constraints for secondary wastewater reclamation. Immersed-type crossflow microfiltration (IMF) was selected as the pretreatment step before reverse osmosis filtration. Secondary wastewater after chlorine contact tank was selected as feed water. The results indicated that the membrane system is capable of producing a filtrate meeting the requirements of both WHO drinking water standards and Malaysian Effluent Standard A. With the application of an automatic backwash process, IMF performed well in hydraulic performance with low fouling rate being achieved. The investigations showed also that chemical cleaning is still needed because of some irreversible fouling by microorganisms always remains. RO treatment with IMF pretreatment process was significantly applicable for wastewater reuse purposes and promised good hydraulic performance.

  17. Radiation-induced graft polymerization of acrylamide: Reverse osmosis properties of polyethylene-g-poly(acrylamide) membrane

    Science.gov (United States)

    Dessouki, Ahmed M.; Hegazy, El-Sayed A.; El-Assy, Nasef B.; El-Boohy, Hussein A.

    A study has been made of some properties of the graft copolymer obtained by direct radiation grafting of acrylamide (AAm) onto low density polyethylene (LDPE) films. The swelling behaviour was investigated for the grafted and alkali-treated graft copolymer and it was found that this depends mainly on the amount of hydrophilic groups and also on the type of electrolytes (K- or Nasalts). salts). Some other properties of the graft copolymer films such as dimensional change wet and dry, electrical conductivity, and mechanical properties were studied. A trial has been made of such membrane for reverse osmosis desalination of saline water. The effect of operating time, degree of grafting, applied pressure and feed concentration on the water flux and salt rejection was determined.

  18. Study of using microfiltration and reverse osmosis membrane technologies for reclaiming cooling water in the power industry.

    Science.gov (United States)

    Li, J; Xu, Z Y; An, H G; Liu, L Q

    2007-07-01

    A study of using dual membrane technologies, microfiltration (MF) and reverse osmosis (RO), for reclaiming blowdown of the cooling tower was conducted at ZJK power plant, Hebei province, China. The study shows that the combined MF-RO system can effectively reduce water consumption in the power industry. The results indicate that MF process is capable of producing a filtrate suitable for RO treatment and achieving a silt density index (SDI) less than 2, turbidity of 0.2 NTU. The water quality of RO effluent is very good with an average conductivity of about 40 micros/cm and rejection of 98%. The product water is suitable for injection into the cooling tower to counteract with cooling water intrusion. After adopting this system, water-saving effectiveness as expressed in terms of cycles of concentration could be increased from 2.5-2.8 times to 5 times.

  19. Biofouling of reverse osmosis membranes: effects of cleaning on biofilm microbial communities, membrane performance, and adherence of extracellular polymeric substances.

    Science.gov (United States)

    Al Ashhab, Ashraf; Sweity, Amer; Bayramoglu, Bihter; Herzberg, Moshe; Gillor, Osnat

    2017-05-01

    Laboratory-scale reverse osmosis (RO) flat-sheet systems were used with two parallel flow cells, one treated with cleaning agents and a control (ie undisturbed). The cleaning efforts increased the affinity of extracellular polymeric substances (EPS) to the RO membrane and altered the biofilm surface structure. Analysis of the membrane biofilm community composition revealed the dominance of Proteobacteria. However, within the phylum Proteobacteria, γ-Proteobacteria dominated the cleaned membrane biofilm, while β-Proteobacteria dominated the control biofilm. The composition of the fungal phyla was also altered by cleaning, with enhancement of Ascomycota and suppression of Basidiomycota. The results suggest that repeated cleaning cycles select for microbial groups that strongly attach to the RO membrane surface by producing rigid and adhesive EPS that hampers membrane performance.

  20. Optimization of ultrafiltration membrane cleaning processes. Pretreatment for reverse osmosis in seawater desalination plants

    OpenAIRE

    Gilabert Oriol, Guillem

    2013-01-01

    Esta tesis explica com mejorar la eficiencia del proceso de ultrafiltración en la desalinización de agua de mar. Esto se consigue optimizando diferentes procesos de limpieza como los contralavados y las limpiezas químicas mejoradas. Para conseguirlo se siguen diferentes estrategias como reducir el número de pasos de los contralavados, reducir la frecuencia de los contralavados, usar salmorra proveniente del concentrado de osmosis y reducir el consumo de químicos. Se propone una nueva metodolo...

  1. The influence to reverse osmosis of the chemical characteristics of water%水化学对反渗透的影响

    Institute of Scientific and Technical Information of China (English)

    贺晨; 张晓辉

    2011-01-01

    I t is importment of the chemical characteristics of water for applying and designing of reverse osmosis I t will be failed when you design and operate reverse osmosisifyou unknown thewater chemical%水的化学特性对反渗透的设计和应用非常重要,不了解水化学将会导致反渗透设计和运行的失败。

  2. Inland Treatment of the Brine Generated from Reverse Osmosis Advanced Membrane Wastewater Treatment Plant Using Epuvalisation System

    Science.gov (United States)

    Qurie, Mohannad; Abbadi, Jehad; Scrano, Laura; Mecca, Gennaro; Bufo, Sabino A.; Khamis, Mustafa; Karaman, Rafik

    2013-01-01

    The reverse osmosis (RO) brine generated from the Al-Quds University wastewater treatment plant was treated using an epuvalisation system. The advanced integrated wastewater treatment plant included an activated sludge unit, two consecutive ultrafiltration (UF) membrane filters (20 kD and 100 kD cutoffs) followed by an activated carbon filter and a reverse osmosis membrane. The epuvalisation system consisted of salt tolerant plants grown in hydroponic channels under continuous water flowing in a closed loop system, and placed in a greenhouse at Al-Quds University. Sweet basil (Ocimum basilicum) plants were selected, and underwent two consecutive hydroponic flowing stages using different brine-concentrations: an adaptation stage, in which a 1:1 mixture of brine and fresh water was used; followed by a functioning stage, with 100% brine. A control treatment using fresh water was included as well. The experiment started in April and ended in June (2012). At the end of the experiment, analysis of the effluent brine showed a remarkable decrease of electroconductivity (EC), PO43−, chemical oxygen demand (COD) and K+ with a reduction of 60%, 74%, 70%, and 60%, respectively, as compared to the influent. The effluent of the control treatment showed 50%, 63%, 46%, and 90% reduction for the same parameters as compared to the influent. Plant growth parameters (plant height, fresh and dry weight) showed no significant difference between fresh water and brine treatments. Obtained results suggest that the epuvalisation system is a promising technique for inland brine treatment with added benefits. The increasing of channel number or closed loop time is estimated for enhancing the treatment process and increasing the nutrient uptake. Nevertheless, the epuvalisation technique is considered to be simple, efficient and low cost for inland RO brine treatment. PMID:23823802

  3. Evaluation of the treatment of reverse osmosis concentrates from municipal wastewater reclamation by coagulation and granular activated carbon adsorption.

    Science.gov (United States)

    Sun, Ying-Xue; Yang, Zhe; Ye, Tao; Shi, Na; Tian, Yuan

    2016-07-01

    Reverse osmosis concentrate (ROC) from municipal wastewater reclamation reverse osmosis (mWRRO) contains elevated concentrations of contaminants which pose potential risks to aquatic environment. The treatment of ROC from an mWRRO using granular activated carbon (GAC) combined pretreatment of coagulation was optimized and evaluated. Among the three coagulants tested, ferric chloride (FeCl3) presented relatively higher DOC removal efficiency than polyaluminium chloride and lime at the same dosage and coagulation conditions. The removal efficiency of DOC, genotoxicity, and antiestrogenic activity concentration of the ROC could achieve 16.9, 18.9, and 39.7 %, respectively, by FeCl3 coagulation (with FeCl3 dosage of 180.22 mg/L), which can hardly reduce UV254 and genotoxicity normalized by DOC of the DOM with MW <5 kDa. However, the post-GAC adsorption column (with filtration velocity of 5.7 m/h, breakthrough point adsorption capacity of 0.22 mg DOC/g GAC) exhibited excellent removal efficiency on the dominant DOM fraction of MW <5 kDa in the ROC. The removal efficiency of DOC, UV254, and TDS in the ROC was up to 91.8, 96, and 76.5 %, respectively, by the FeCl3 coagulation and post-GAC adsorption. Also, the DOM with both genotoxicity and antiestrogenic activity were completely eliminated by the GAC adsorption. The results suggest that GAC adsorption combined pretreatment of FeCl3 coagulation as an efficient method to control organics, genotoxicity, and antiestrogenic activity in the ROC from mWRRO system.

  4. Characterization and biotoxicity assessment of dissolved organic matter in RO concentrate from a municipal wastewater reclamation reverse osmosis system.

    Science.gov (United States)

    Sun, Ying-Xue; Gao, Yue; Hu, Hong-Ying; Tang, Fang; Yang, Zhe

    2014-12-01

    Reverse osmosis (RO) concentrate from municipal wastewater reclamation reverse osmosis (mWRRO) system containing organic compounds may associate with toxic risk, and its discharge might pose an environmental risk. To identify a basis for the selection of feasible technology in treating RO concentrates, the characteristics and biotoxicity of different fractions of dissolved organic matter (DOM) in RO concentrates from an mWRRO system were investigated. The results indicated that the hydrophilic neutrals (HIN), hydrophobic acids (HOA) and hydrophobic bases (HOB) accounted for 96% of the dissolved organic carbon (DOC) of the total DOM in the RO concentrate. According to the SEC chromatograph detected at 254 nm wavelength of UV, the DOM with molecular weight (MW) 1-3 kDa accounted for the majority of the basic and neutral fractions. The fluorescence spectra of the excitation emission matrix (EEM) indicated that most aromatic proteins, humic/fulvic acid-like and soluble microbial by-product-like substances existed in the fractions HOA and hydrophobic neutrals (HON). The genotoxicity and anti-estrogenic activity of the RO concentrate were 1795.6 ± 57.2 μg 4-NQOL(-1) and 2.19 ± 0.05 mg TAM L(-1), respectively. The HIN, HOA, and HOB contributed to the genotoxicity of the RO concentrate, and the HIN was with the highest genotoxic level of 1007.9 ± 94.8 μg 4-NQOL(-1). The HOA, HON, and HIN lead to the total anti-estrogenic activity of the RO concentrate, and HOA occupied approximately 60% of the total, which was 1.3 ± 0.17 mg TAM L(-1).

  5. Analysis of a Wave-Powered, Reverse-Osmosis System and Its Economic Availability in the United States: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jenne, Dale S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-09

    A wave energy converter (WEC) system has the potential to convert the wave energy resource directly into the high-pressure flow that is needed by the desalination system to permeate saltwater through the reverse-osmosis membrane to generate clean water. In this study, a wave-to-water numerical model was developed to investigate the potential use of a wave-powered desalination system (WPDS) for water production in the United States. The model was developed by coupling a time-domain radiation-and-diffraction-method-based numerical tool (WEC-Sim) for predicting the hydrodynamic performance of WECs with a solution-diffusion model that was used to simulate the reverse-osmosis process. To evaluate the feasibility of the WPDS, the wave-to-water numerical model was applied to simulate a desalination system that used an oscillating surge WEC device to pump seawater through the system. The annual water production was estimated based on the wave resource at a reference site on the coast of northern California to investigate the potential cost of water in that area, where the cost of water and electricity is high compared to other regions. In the scenario evaluated, for a 100-unit utility-scale electricity-producing array, the estimated levelized cost of energy for these WECs is about 3-6 times the U.S.'s current, unsubsidized electricity rates. However, with clean water as an end product and by directly producing pressurized water with WECs, rather than electricity as an intermediary, it is presently only 12 percent greater than typical water cost in California. This study suggests that a WEC array that produces water may be a viable, near-term solution to the nation's water supply, and the niche application of the WPDS may also provide developers with new opportunities to further develop technologies that benefit both the electric and drinking water markets.

  6. Inland Treatment of the Brine Generated from Reverse Osmosis Advanced Membrane Wastewater Treatment Plant Using Epuvalisation System

    Directory of Open Access Journals (Sweden)

    Mohannad Qurie

    2013-07-01

    Full Text Available The reverse osmosis (RO brine generated from the Al-Quds University wastewater treatment plant was treated using an epuvalisation system. The advanced integrated wastewater treatment plant included an activated sludge unit, two consecutive ultrafiltration (UF membrane filters (20 kD and 100 kD cutoffs followed by an activated carbon filter and a reverse osmosis membrane. The epuvalisation system consisted of salt tolerant plants grown in hydroponic channels under continuous water flowing in a closed loop system, and placed in a greenhouse at Al-Quds University. Sweet basil (Ocimum basilicum plants were selected, and underwent two consecutive hydroponic flowing stages using different brine-concentrations: an adaptation stage, in which a 1:1 mixture of brine and fresh water was used; followed by a functioning stage, with 100% brine. A control treatment using fresh water was included as well. The experiment started in April and ended in June (2012. At the end of the experiment, analysis of the effluent brine showed a remarkable decrease of electroconductivity (EC, PO43−, chemical oxygen demand (COD and K+ with a reduction of 60%, 74%, 70%, and 60%, respectively, as compared to the influent. The effluent of the control treatment showed 50%, 63%, 46%, and 90% reduction for the same parameters as compared to the influent. Plant growth parameters (plant height, fresh and dry weight showed no significant difference between fresh water and brine treatments. Obtained results suggest that the epuvalisation system is a promising technique for inland brine treatment with added benefits. The increasing of channel number or closed loop time is estimated for enhancing the treatment process and increasing the nutrient uptake. Nevertheless, the epuvalisation technique is considered to be simple, efficient and low cost for inland RO brine treatment.

  7. Biofouling potential reductions using a membrane hybrid system as a pre-treatment to seawater reverse osmosis.

    Science.gov (United States)

    Jeong, Sanghyun; Kim, Lan Hee; Kim, Sung-Jo; Nguyen, Tien Vinh; Vigneswaran, Saravanamuthu; Kim, In S

    2012-07-01

    Biofouling on reverse osmosis (RO) membranes is the most serious problem which affects desalination process efficiency and increases operation cost. The biofouling cannot be effectively removed by the conventional pre-treatment traditionally used in desalination plants. Hybrid membrane systems coupling the adsorption and/or coagulation with low-pressure membranes can be a sustainable pre-treatment in reducing membrane fouling and at the same time improving the feed water quality to the seawater reverse osmosis. The addition of powder activated carbon (PAC) of 1.5 g/L into submerged membrane system could help to remove significant amount of both hydrophobic compounds (81.4%) and hydrophilic compounds (73.3%). When this submerged membrane adsorption hybrid system (SMAHS) was combined with FeCl(3) coagulation of 0.5 mg of Fe(3+)/L, dissolved organic carbon removal efficiency was excellent even with lower dose of PAC (0.5 g/L). Detailed microbial studies conducted with the SMAHS and the submerged membrane coagulation-adsorption hybrid system (SMCAHS) showed that these hybrid systems can significantly remove the total bacteria which contain also live cells. As a result, microbial adenosine triphosphate (ATP) as well as total ATP concentrations in treated seawater and foulants was considerably decreased. The bacteria number in feed water prior to RO reduced from 5.10E(+06) cells/mL to 3.10E(+03) cells/mL and 9.30E(+03) cells/mL after SMAHS and SMCAHS were applied as pre-treatment, respectively. These led to a significant reduction of assimilable organic carbon (AOC) by 10.1 μg/L acetate-C when SMCAHS was used as a pre-treatment after 45-h RO operation. In this study, AOC method was modified to measure the growth of bacteria in seawater by using the Pseudomonas P.60 strain.

  8. Inland treatment of the brine generated from reverse osmosis advanced membrane wastewater treatment plant using epuvalisation system.

    Science.gov (United States)

    Qurie, Mohannad; Abbadi, Jehad; Scrano, Laura; Mecca, Gennaro; Bufo, Sabino A; Khamis, Mustafa; Karaman, Rafik

    2013-07-03

    The reverse osmosis (RO) brine generated from the Al-Quds University wastewater treatment plant was treated using an epuvalisation system. The advanced integrated wastewater treatment plant included an activated sludge unit, two consecutive ultrafiltration (UF) membrane filters (20 kD and 100 kD cutoffs) followed by an activated carbon filter and a reverse osmosis membrane. The epuvalisation system consisted of salt tolerant plants grown in hydroponic channels under continuous water flowing in a closed loop system, and placed in a greenhouse at Al-Quds University. Sweet basil (Ocimum basilicum) plants were selected, and underwent two consecutive hydroponic flowing stages using different brine-concentrations: an adaptation stage, in which a 1:1 mixture of brine and fresh water was used; followed by a functioning stage, with 100% brine. A control treatment using fresh water was included as well. The experiment started in April and ended in June (2012). At the end of the experiment, analysis of the effluent brine showed a remarkable decrease of electroconductivity (EC), PO43-, chemical oxygen demand (COD) and K+ with a reduction of 60%, 74%, 70%, and 60%, respectively, as compared to the influent. The effluent of the control treatment showed 50%, 63%, 46%, and 90% reduction for the same parameters as compared to the influent. Plant growth parameters (plant height, fresh and dry weight) showed no significant difference between fresh water and brine treatments. Obtained results suggest that the epuvalisation system is a promising technique for inland brine treatment with added benefits. The increasing of channel number or closed loop time is estimated for enhancing the treatment process and increasing the nutrient uptake. Nevertheless, the epuvalisation technique is considered to be simple, efficient and low cost for inland RO brine treatment.

  9. INFLUENCE AT DIFFERENT OPERATION CONDITIONS ON THE ACEROLA JUICE CONCENTRATION BY REVERSE OSMOSIS, USING SPIRAL MEMBRANE OF COMPOSITE FILM

    Directory of Open Access Journals (Sweden)

    E. R.S. GOMES

    2009-03-01

    Full Text Available

    The concentration of acerola juice, involves removal of water with the objective of reducing packing, storage and transport costs. The reverse osmosis (RO is a process of increasing interest in food industry and among the advantages they stand out: the low consumption of energy and the minimum thermal damages is caused to the products. The objective of this work was to evaluate the influence of different operation conditions in relation to the permeate flux, in the concentration process of the acerola juice by RO. All the RO experiments were carried out with retentate recycling. The concentration by RO, were carried on the transmembrane pressures of 20, 30 and 40 bar and at 23ºC and 40ºC, being used a membrane of composite film in spiral module (99% NaCl rejection. The acerola pulp was defrosted and treated with Citrozym Ultra L enzyme (100 ppm, 45ºC ,1 hour, then it was ultrafiltrated at 3 bar at the same temperature, in 0.1 µm ceramic membrane, and so it was concentrated by RO. It was verified that the pressure and the temperature influenced the concentration and the permeate flux obtained in the RO process. The flux decreased along the processing, once the feeding becomes more concentrate, increasing the viscosity, osmotic pressure and retained sugar. KEYWORDS: Acerola juice concentration; reverse osmosis; membrane of composite film.

  10. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    KAUST Repository

    Louie, Jennifer Sarah

    2011-02-01

    The application of polymer surface coatings to improve the fouling resistance of reverse osmosis membranes tends to increase flow resistance across the membrane. This paper presents a systematic analysis on how membrane properties and performance are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux, which is attributed to wetting of pores in the selective polyamide layer and to changes in the polymer structure. This flux increase was not readily reversible, based on a 300-h water permeation test. Conversely, drying a wetted membrane led to a decrease in water flux, which we hypothesize is caused by increased interchain hydrogen-bonding in the selective layer. This drop in water flux was not permanent; higher flux was observed if the same wetted/dried membrane was then re-soaked in ethanol prior to the water permeation experiment. An ethanol pre-soaking step also increased water flux of a PEBAX-coated membrane by nearly 70%. In contrast to the reduction in water flux caused by the specific treatment sequence of ethanol-swelling followed by drying, this same sequence actually increased gas transport. The eight- to ten-fold increase in Knudsen diffusion-based gas permeance after this pre-treatment was attributed to an increase in the number or size of membrane defects. © 2010 Elsevier B.V.

  11. 反渗透系统的效能影响因素分析%Analysis of Factors Influencing Efficiency of Reverse Osmosis System

    Institute of Scientific and Technical Information of China (English)

    王鹏; 李松良; 华常春

    2012-01-01

    从膜自身的结构特性、膜系统运行的条件以及进水水质等方面,对反渗透效能具有影响作用的因素进行分析,找出具体的解决办法和适当的操作条件,使其在使用过程中增强反渗透膜的抗污染性、延长使用寿命、降低清洗的次数。%Analysis of factors influencing reverse osmosis efficiency is made in this article mainly from the structural characteristics of membrane itself, working conditions of membrane system and quality of incoming water. Then, the specific solutions and proper operating conditions are achieved, which can enhance pollution resistibility of reverse osmosis membrane, extend service life and reduce washing times in the working process.

  12. To investigate the reverse osmosis system online chemical cleaning%反渗透系统在线化学清洗的探讨

    Institute of Scientific and Technical Information of China (English)

    李虹

    2014-01-01

    By optimizing and improving the formula and the cleaning solution of reverse osmosis system online chemical cleaning of the second soft water station of Han dan Iron and Steel Company's east area,we have the chemical cleaning experiment to explore a set of reverse osmosis system cleaning technology suitable for the use of Han dan Iron and Steel Company's present double membrane technology positions.%通过对邯钢东区第二软水站的反渗透系统在线化学清洗配方及清洗方案进行优化、改进,进行化学清洗试验,摸索出一套适合目前邯钢双膜法岗位的反渗透系统清洗技术。

  13. Influencing factors of reverse osmosis membranes off-line cleaning%反渗透膜离线清洗影响因素

    Institute of Scientific and Technical Information of China (English)

    王磊; 王峰; 胡志强; 董敏华

    2013-01-01

    There are many factors that have influence on the efficacy of reverse osmosis membranes off-line cleaning. Based on the summary of the off-line chemical cleaning practice, the factors that can affect cleaning results are analyzed, so as to decide suitable off-line cleaning conditions, and provide certain technical support to reverse osmosis membranes off-line cleaning in the future.%影响反渗透膜离线化学清洗效果的因素较多,通过对反渗透膜离线化学清洗实践的总结,对影响其清洗效果的因素进行分析,从而确定合适的离线清洗条件,为今后反渗透膜离线清洗提供一定的技术支持.

  14. Modelamento of osmosis system reverse set in motion by a photovoltaic generator; Modelamento de sistema de osmose reversa acionado por um gerador fotovoltaico

    Energy Technology Data Exchange (ETDEWEB)

    Fraidenraich, N.; Vilela, O. C.; Lima, G. A.

    2008-07-01

    A theoretical model to study the operational conditions of Reverse Osmosis systems (RO) is presented. The model is applied to simulate the behavior of a Photovoltaic-Powered Reverse Osmosis System (PV-RO) monitored with sensors for measuring water flow, salinity, pressure voltage and current of operation. the system is powered by a PV generator with peak power of 0.81 kW. The interface of the PV generator and the motor-pump is a frequency converter, programmed to maintain the array working at a fixed voltage, chosen within the region of the maximum power. Considering the relation given by the load curve (pressure vs. feed flow rate) the permeated flow rate was determined theoretically for a given membrane length. The deviation between calculated and experimental results is smaller than 14.5%. The model can be used to determine parameters important in the sizing of those systems. (Author)

  15. A feasibility study of ultrafiltration/reverse osmosis (UF/RO)-based wastewater treatment and reuse in the metal finishing industry

    DEFF Research Database (Denmark)

    Petrinic, Irena; Korenak, Jasmina; Povodnik, Damijan

    2015-01-01

    , potable water use for industrial process and pre-treatment, and taxes) were compared with the investment required to implement the ultrafiltration-reverse osmosis processes. Based on the presented scientific results, the analysis shows that there is a potential for implementing this process within......Conventional treatment of wastewater from the metal finishing industry is generally based on physical-chemical treatment. Although the effluents from this can be discharged directly there is an increasing interest in industrial wastewater reuse. This requires further wastewater treatment. Here we...... that the ultrafiltration-reverse osmosis treatment removed between 91.3% and 99.8% of the contaminants from the effluent, such as metal elements, organic, and inorganic compounds. Contaminants such as suspended solids, nickel, ammonium nitrogen, sulphate nitrogen, chemical oxygen demand, and biochemical oxygen demand were...

  16. Handling concentrated water with reverse osmosis technology and economize water%反渗透工艺处理浓水节约水资源

    Institute of Scientific and Technical Information of China (English)

    张秀玲; 杨潘溪; 吴华

    2012-01-01

    反渗透工艺作为一种高效、清洁的脱盐技术在各行各业中广泛应用,但是在生产过程中实际产水率70%左右,会有大约占总进水量30%左右的浓水排放掉,这一点在水资源日趋紧缺的今天造成了水资源的极大浪费,而且也严重污染了环境。现简要介绍对反渗透浓水采用反渗透技术和设备来进一步处理,可以使反渗透浓水的回收率达到80%-85%,回收水可以再利用,节约了水资源。%As a kind of high efficient, clean desalting technology, reverse osmosis technology is widely applied in all walks of life. However, actual rate of out flow is about 70% in production process, the rest 30% of the total water inflow concentrated water is drained off which not only causes a tremendous waste of water resources today when water resource is in short, but also it pollutes environment seriously. This paper briefly introduces adopting reverse osmosis technology and equipments to reverse osmosis concentrated water, which can make the rate of reverse osmosis concentrated water reach 80%-85%, recycled water can be reused and saving water resources.

  17. 全自动在线血透水处理系统的设计%Design of automatic reverse osmosis water system

    Institute of Scientific and Technical Information of China (English)

    贺昕路; 顾伟新

    2015-01-01

    Objective:To design automatic reverse osmosis water system with new design idea of reverse osmosis water system, to make sure of the procedure. Methods:During the design, using microcomputer technology to control water preparation and disinfection. Results:Using MCU to control preparation of water and disinfection, in order to monitor water quality. If water quality exceeds the standard, the system will alarm and generate records. Conclusion: Using microcomputer technology to design Reverse osmosis water system, not only reducing artificial, but also to improve the safety and controllability, even the quality control of reverse osmosis water system.%目的:运用全新的水处理系统的设计思想,设计全自动血透水处理系统,确定水处理工艺流程。方法:在设计水处理过程中,应用单片机技术,对水处理系统的制水和消毒过程进行实时控制。结果:利用单片机技术在制水和消毒过程中,控制水处理系统,实时监控各个水质指标。当指标超标时系统自动报警并生成记录。结论:将单片机技术应用到水处理系统中,不仅降低了人工损耗,也提高了系统的安全性和可控性,同时对水处理系统进行质量控制。

  18. 反渗透系统运行存在的问题及解决方案%Problems and Solutions in Operation of Reverse Osmosis System

    Institute of Scientific and Technical Information of China (English)

    罗洁; 李文强; 王开; 李言郡; 翟鹏贵

    2016-01-01

    目前,由于水污染问题日趋严重,水质越来越差。为了满足生产要求,很多领域都已经开始使用反渗透设备,反渗透已然成为水处理领域的主导技术。然而,在反渗透处理过程中,膜污染始终是制约该技术得以广泛应用的瓶颈之一。通过分析膜污染的影响因素,研究控制污染的工艺,可以极大提高反渗透的出水水质,延长其使用寿命,降低其运行成本。%Nowadays,as water pollution is becoming increasingly serious,water quality is getting worse and worse. The reverse osmosis has become the dominant technology in water treatment area,and the reverse osmosis equipments have been widely used in many fields in order to meet the production requirements. However,membrane fouling has always been one of the bottlenecks that restrict the wide promotion of the technology of reverse osmosis process. Through the analysis of membrane fouling factors and study on pollution control technology,we could greatly improve the effluent quality,extend the life of reverse osmosis and reduce its operating costs.

  19. 反渗透海水淡化系统火用分析及计算%Exergy Analysis and Calculation of Reverse Osmosis Desalination System

    Institute of Scientific and Technical Information of China (English)

    于宗坤

    2014-01-01

    Based on the method of exergy analysis ,this article analyzes the exergy efficiency and exergy loss of all equipments in the reverse osmosis desalination system ,and combines with the actual case calculation .The results show :the exergy loss rate of membrane module in the system is maximum ,and the exergy efficiency is lower ,so the membrane module is the key factorof the energy efficiency level of reverse osmosis desalina-tion system ;high pressure pump is themajor energy -using equipment in the reverse osmosis desalination system ,and the key to decrease the cost of water reverse osmosis desalination system is to improve the mem-brane performance and reduce the cost of the high pressure water .%基于火用分析方法对反渗透海水淡化系统中各设备的火用效率和火用损失进行了分析,并结合实际案例进行了计算。结果表明:系统中膜组件火用损率最大,火用效率较低,是影响反渗透海水淡化系统能效水平提高的关键因素,高压泵是反渗透海水淡化系统主要的用能设备,降低反渗透海水淡化制水成本的关键是改善膜性能和降低制备高压海水的成本。

  20. The Analysis of Instrument Selection in Reverse Osmosis Desalination Systems%反渗透海水淡化系统仪表选型分析

    Institute of Scientific and Technical Information of China (English)

    孙迎杰

    2016-01-01

    要科学合理地了解反渗透海水淡化系统的运行状况,离不开各类监测仪表的支持。本文首先介绍反渗透海水淡化系统的基本工艺流程,接着阐述了为实现对运行状况的监控,相应仪表应具备的基本功能,最后分析了反渗透海水淡化系统中常用的监测仪表选型原则,包括温度、压力、流量以及液位等系统运行过程参数监测仪表,以及电导率仪、浊度计、pH计等水质参数监测仪表,可为反渗透海水淡化工程中仪表选型提供参考。%With the support of monitoring instruments, we are able to know the operational state of reverse osmosis desalination systems scientifically and reasonably. This paper introduces the basic process of reverse osmosis desalination systems, then elaborates what functions the instruments should have to monitor the operational status. On this basis, it analyzes the selection principles of monitoring instruments used in reverse osmosis desalination systems, including monitoring process operating parameters like temperature, pressure, flow, level and so on, as well as monitoring water quality parameters, such as conductivity, turbidity, pH, etc. It could provide reference for instrument selection in reverse osmosis desalination projects.

  1. Effects of reverse osmosis preparation deionized water operation factors%影响反渗透制备脱离子水的运行因素

    Institute of Scientific and Technical Information of China (English)

    陈华; 赵世伟; 夏鑫; 吕冰

    2012-01-01

    Reasons on effects of reverse osmosis preparation deionized water operation factors. Focusing analysis was proceeding, and the prevention measures were put forward.%介绍了影响反渗透装置制备脱离子水的运行因素并进行了有针对性的分析,提出了相应的预防措施。

  2. Feedwater production from river water with ion exchange and reverse osmosis. 10 years operation experience; Kesselspeisewasser-Erzeugung aus Flusswasser durch Ionenaustausch und Umkehrosmose. 10 Jahre Betriebserfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Wasel-Nielen, J.; Kluge, H. [InfraServ GmbH und Co. Hoechst KG, Frankfurt am Main (Germany)

    2000-07-01

    Since november 1988 the InfaServ Hoechst KG in Frankfurt am Main processes river water to be used as desalinated feedwater for high pressure steam boilers. Main purposes for the use of reverse osmosis were the reduction of waste water for regeneration and separation of organics contributing to boiler corrosion. Development of a new low pressure membrane reduced the energy demand. Biofouling proofed to be a main problem. Performance and cost are shown.

  3. Development and demonstration of a mobile reverse osmosis adsorption treatment system for environmental emergency clean-ups. Report No. EE-102

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    This study is concerned with the remedation of contaminated water resulting from the release of organic chemicals. Of particular concern is the cleanup of water contaminated by accidental spill of chemicals or petroleum products and the cleanup of water contaminated by oil chemicals disposed of in inadequately sealed or improperly designed landfills. This report presents the results of a project undertaken to develop and demonstrate a mobile reverse osmosis/adsorption system for treating water contaminated by organic chemicals.

  4. Towards temperature driven forward osmosis desalination using Semi-IPN hydrogels as reversible draw agents.

    Science.gov (United States)

    Cai, Yufeng; Shen, Wenming; Loo, Siew Leng; Krantz, William B; Wang, Rong; Fane, Anthony G; Hu, Xiao

    2013-07-01

    We report a study to explore new materials and a new concept for temperature driven quasi-continuous desalination using hydrogels as draw agents in forward osmosis (FO). This concept is enabled by the design and preparation of thermally responsive hydrogels having a semi-interpenetrating network (semi-IPN) structure. Thermally responsive semi-IPN hydrogels were synthesized by polymerization of N-isopropylacrylamide (NIPAm) in the presence of polysodium acrylate (PSA) or polyvinyl alcohol (PVA). Their functions as draw agents in FO were systematically studied and compared with hydrogels prepared from the PNIPAm homopolymer or the NIPAM-SA copolymer. While the semi-IPN hydrogels displayed the desirable balanced thermally responsive swelling and dewatering behavior, the NIPAm-SA copolymer hydrogels were found to have poor dewatering behavior, making them unsuitable for a continuous temperature driven desalination process. At 40 °C, the semi-IPN hydrogels rapidly release nearly 100% of the water absorbed during the FO drawing process carried out at room temperature. Results clearly indicate the potential of semi-IPN hydrogels as semi-solid draw agents in the FO process, in which quasi-continuous desalination could be achieved by cyclic heating and cooling within a moderate temperature change.

  5. Boron in reverse osmosis water desalination: current situational and applying technologies for its removal; El boro en las aguas desaladas por osmosis inversa: situacion actual y tecnologias aplicables para su eliminacion

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Sanz, M.; Penate Suarez, B.

    2007-07-01

    In most of the seawater reverse osmosis desalination plants operating in one stage, the water produced presents values bordering or exceeding the limit established by the Spanish legislation for boron content of 1mg/l. As well as on the intrinsic features of the membrane elements, the boron removal in the desalination process depends on various factors. In this article the most relevant ones are described and a synopsis of the applied technologies and designs is introduced in order to fulfil current regulations. (Author)

  6. Preventing colloidal fouling in reverse osmosis and nano filtration system. Application of electron beam surface analysis; Prevencion del ensuciamiento coloidal en sistemas de osmosis inversa y nanofiltracion. Aplicacion del analisis de superficies con haces de electrones.

    Energy Technology Data Exchange (ETDEWEB)

    Sanz Ataz, J.; Guerrero Gallego, L.; Taberna Camprubi, E.; Pena Garcia, N.M; Carulla Contreras, C.; Blavia Bergos, J.

    2003-07-01

    Particulate matter in natural waters and wastewaters can cause fouling in reverse osmosis and nano filtration membranes. Common foulants includes organic and inorganic colloids; hydrous aluminum and iron silicates, silt, iron and manganese oxides, calcium carbonate, microorganisms, polysaccharides, lipoproteins, biological debris, etc. Predicting fouling of dispersed materials on membrane surface and brine flow channels uses the silt density index (SDI) and modified fouling index (MFI). Scanning electron microscopy (SEM) coupled with energy X-ray microanalysis (EDX) of SDI filters contributes to obtain information about shape, size and chemical composition of foulants and cake layer. (Author) 6 refs.

  7. 反渗透膜有机污染的控制方法%ControI methods for organic fouIing in reverse osmosis membranes

    Institute of Scientific and Technical Information of China (English)

    谢文州; 郦和生

    2015-01-01

    Recent research progress in the control methods for organic fouling of reverse osmosis membranes has been summarized. The organic fouling of reverse osmosis membranes can all be controlled effectively by pre-treating influent water,optimizing operating conditions,adding scale inhibitors,and modifying and cleaning membrane sur-face. The research trend of the control methods for the organic fouling of reverse osmosis membranes is proposed.%综述了近年来反渗透膜有机污染控制方法的研究进展,其中进水预处理、优化操作条件、添加阻垢剂、膜表面改性和清洗对反渗透膜的有机污染均能进行有效的控制,提出了反渗透膜有机污染控制方法的研究方向。

  8. Study and Application of Polyamide Reverse Osmosis Feature Film%聚酰胺复合反渗透功能膜的研究及应用

    Institute of Scientific and Technical Information of China (English)

    袁飞

    2011-01-01

    With polyamide reverse osmosis membrane made of demineralized water features.Focusing on the inhibitor,sanitizers,water stress,water temperature,and other conditions on the polyamide reverse osmosis applications.Results indicated that: the inhibitor,sanitizers,water stress,water temperature,and other conditions of moderate,polyamide reverse osmosis feature film health to security,the economy.%采用聚酰胺复合反渗透功能膜制得脱盐水。重点讨论了阻垢剂、杀菌剂、进水压力、进水温度等条件对聚酰胺复合反渗透功能膜应用的影响。结果表明:阻垢剂、杀菌剂、进水压力、进水温度等条件适中时,聚酰胺复合反渗透功能膜才能安全、经济运行。

  9. 反渗透系统运行存在的问题及解决方案%Problems and Solutions in Operation of Reverse Osmosis System

    Institute of Scientific and Technical Information of China (English)

    吉晓斌; 李峰

    2011-01-01

    Surface water was used as raw water for the reverse osmosis system in an chemical plant. Since biological pollutants exist in surface water, serious blockage has ocured in the reverse osmosis system as a result. According to the operating problems resulted from the surface water quality, how to solve the problems such as improving pre-treatment system, eliminating defect of hidden devices, strengthening online cleaning and adding proper chemical agents synchronously was introduced. Finally, the reverse osmosis system can work normally.%某化工装置的反渗透系统以地表水为源水,由于地表水经常发生生物污染现象,造成反渗透系统发生严重的堵塞问题.针对由地表水水质引起的反渗透系统运行问题,该文介绍了通过改进预处理系统、消除设备缺陷、加强在线清洗,配合以合适的阻垢化学药剂处理改进等措施,最终使反渗透系统恢复正常运行.

  10. Characterization and Evaluation of the Improved Performance of Modified Reverse Osmosis Membranes by Incorporation of Various Organic Modifiers and SnO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Kh. M. AL-Sheetan

    2015-01-01

    Full Text Available Reverse osmosis (RO membranes modified with SnO2 nanoparticles of varied concentrations (0.001–0.1 wt.% were developed via in situ interfacial polymerization (IP of trimesoyl chloride (TMC and m-phenylenediamine (MPD on nanoporous polysulfone supports. The nanoparticles dispersed in the dense nodular polyamide on the polysulfone side. The effects of IP reaction time and SnO2 loading on membrane separation performance were studied. The modified reverse osmosis membranes were characterized by scanning electron microscopy (SEM, X-ray diffractometer (XRD, energy dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, contact angle measurement, and atomic force microscopy (AFM. The synthesized SnO2 nanoparticles size varies between 10 and 30 nm. The results exhibited a smooth membrane surface and average surface roughness from 31 to 68 nm. Moreover, hydrophilicity was enhanced and contact angle decreased. The outcomes showed that an IP reaction time was essential to form a denser SnO2-polyamide layer for higher salt rejection, the developed reverse osmosis membranes with the incorporation of the SnO2 nanoparticles were examined by measuring permeate fluxes and salt rejection, and the permeate flux increased from 26 to 43.4 L/m2·h, while salt rejection was high at 98% (2000 ppm NaCl solution at 225 psi (1.55 MPa, 25°C.

  11. 海水反渗透淡化技术的分析与探讨%Analysis and discussion on seawater desalination by reverse osmosis technology

    Institute of Scientific and Technical Information of China (English)

    李赞忠; 乔子荣

    2011-01-01

    反渗透海水淡化技术是一种高效、节能、先进的液体分离技术.论述了目前国内外海水反渗透淡化技术的应用现状,着重介绍了反渗透膜材料及特点、膜污染及清洗、典型的海水反渗透淡化流程,探讨了反渗透海水淡化技术目前存在的问题及未来发展趋势.%Seawater desalination utilizing reverse osmosis technology is an efficient, energy saving, advanced liquid separation technology. The application and the current situation of seawater desalination by reverse osmosis technology in China and abroad are discussed,focusing on the materials and characteristics of membranes,fouling and cleaning of membranes, and typical seawater desalination process. Meanwhile the existing problems and future trends of seawater desalination utilizing reverse osmosis technology are also discussed.

  12. Biochar-based constructed wetlands to treat reverse osmosis rejected concentrates in chronic kidney disease endemic areas in Sri Lanka.

    Science.gov (United States)

    Athapattu, B C L; Thalgaspitiya, T W L R; Yasaratne, U L S; Vithanage, Meththika

    2017-03-13

    The objectives were to investigate the potential remedial measures for reverse osmosis (RO) rejected water through constructed wetlands (CWs) with low-cost materials in the media established in chronic kidney disease of unknown etiology (CKDu) prevalent area in Sri Lanka. A pilot-scale surface and subsurface water CWs were established at the Medawachchiya community-based RO water supply unit. Locally available soil, calicut tile and biochar were used in proportions of 81, 16.5 and 2.5% (w/w), respectively, as filter materials in the subsurface. Vetiver grass and Scirpus grossus were selected for subsurface wetland while water lettuce and water hyacinth were chosen for free water surface CWs. Results showed that the CKDu sensitive parameters; total dissolved solids, hardness, total alkalinity and fluoride were reduced considerably (20-85%) and most met desirable levels of stipulated ambient standards. Biochar seemed to play a major role in removing fluoride from the system which may be due to the existing and adsorbed K(+), Ca(+2), Mg(+2), etc. on the biochar surface via chemisorption. The least reduction was observed for alkalinity. This study indicated potential purification of aforesaid ions in water which are considerably present in RO rejection. Therefore, the invented bio-geo constructed wetland can be considered as a sustainable, economical and effective option for reducing high concentrations of CKDu sensitive parameters in RO rejected water before discharging into the inland waters.

  13. Rejection of pharmaceuticals and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs) by low pressure reverse osmosis membranes.

    Science.gov (United States)

    Ozaki, H; Ikejima, N; Shimizu, Y; Fukami, K; Taniguchi, S; Takanami, R; Giri, R R; Matsui, S

    2008-01-01

    This paper aims to elucidate retention characteristics of some pharmaceuticals and personal care products (PPCPs), and endocrine disrupting chemicals (EDCs), by two polyamide low pressure reverse osmosis (LPRO) membranes. Feed solution pH did not have an influence on rejections of undissociated solutes, which was most likely governed by adsorption, size exclusion and diffusion simultaneously. Size exclusion was presumably dominant, especially with tight membranes (UTC-70U). Rejections of the solutes with low dipole moment (diffusion coefficient (D(p)). The rejections decreased with increasing D(p) values irrespective of their dipole moments. Rejections of solutes with comparatively larger dipole moments might be dominated by diffusion and/or convection rather than their hydrophobicity. However, rejections of solutes with hydroxyl and carboxyl functional groups by UTC-60 increased with solution pH. More than 80% rejections were obtained for degree of dissociation (alpha)>0.5. Electrostatic repulsion played a key role for rejection of dissociated solutes, especially by loose LPRO membranes. Therefore, assessing the dissociation degree at desired pH values can be a key step to obtain an insight of rejection mechanisms by polyamide membranes.

  14. Full-scale simulation of seawater reverse osmosis desalination processes for boron removal: Effect of membrane fouling.

    Science.gov (United States)

    Park, Pyung-Kyu; Lee, Sangho; Cho, Jae-Seok; Kim, Jae-Hong

    2012-08-01

    The objective of this study is to further develop previously reported mechanistic predictive model that simulates boron removal in full-scale seawater reverse osmosis (RO) desalination processes to take into account the effect of membrane fouling. Decrease of boron removal and reduction in water production rate by membrane fouling due to enhanced concentration polarization were simulated as a decrease in solute mass transfer coefficient in boundary layer on membrane surface. Various design and operating options under fouling condition were examined including single- versus double-pass configurations, different number of RO elements per vessel, use of RO membranes with enhanced boron rejection, and pH adjustment. These options were quantitatively compared by normalizing the performance of the system in terms of E(min), the minimum energy costs per product water. Simulation results suggested that most viable options to enhance boron rejection among those tested in this study include: i) minimizing fouling, ii) exchanging the existing SWRO elements to boron-specific ones, and iii) increasing pH in the second pass. The model developed in this study is expected to help design and optimization of the RO processes to achieve the target boron removal at target water recovery under realistic conditions where membrane fouling occurs during operation.

  15. The use of microbial and chemical analyses to characterize the variations in fouling profile of seawater reverse osmosis (SWRO) membrane

    KAUST Repository

    Manes, Carmem Lara De O

    2013-01-01

    Biofouling of reverse osmosis (RO) membranes is one of the most common problems in desalinations plants reducing the efficiency of the water production process. The characterization of bacterial community composition from fouling layers as well as detailed analysis of surrounding chemical environment might reveal process specific bacterial groups/species that are involved in RO biofouling. In this study, advanced organics analytic methods (elemental analysis, FTIR, and ICP-OES) were combined with high-throughput 16S rRNA (pyro) sequencing to assess in parallel, the chemical properties and the active microbial community composition of SWRO membranes from a pilot desalination plant (MFT, Tarragona) in February 2011 and July 2011. Prefiltered ultrafiltration. waters fed SWRO membranes during third and fifth month of operation, respectively. SWRO samples were taken from three modules at different positions (first, fourth, and sixth) in order to investigate the spatial changes in fouling layers\\' chemical and microbiological composition. The overall assessment of chemical parameters revealed that fouling layers were mainly composed by bio and organic material (proteins and lipids). Ca and Fe were found to be the most abundant elements having an increasing concentration gradient according to the module position. Bacterial community composition of SWRO membranes is mostly represented by the Gammaproteobacteria class with interesting differences in genera/species spatial and temporal distribution. This preliminary result suggests that pretreatments and/or operational conditions might have selected different bacterial groups more adapted to colonize SWRO membranes. © 2013 Desalination Publications.

  16. Fouling of a spiral-wound reverse osmosis membrane processing swine wastewater: effect of cleaning procedure on fouling resistance.

    Science.gov (United States)

    Camilleri-Rumbau, M S; Masse, L; Dubreuil, J; Mondor, M; Christensen, K V; Norddahl, B

    2016-01-01

    Swine manure is a valuable source of nitrogen, phosphorus and potassium. After solid-liquid separation, the resulting swine wastewater can be concentrated by reverse osmosis (RO) to produce a nitrogen-potassium rich fertilizer. However, swine wastewater has a high fouling potential and an efficient cleaning strategy is required. In this study, a semi-commercial farm scale RO spiral-wound membrane unit was fouled while processing larger volumes of swine wastewater during realistic cyclic operations over a 9-week period. Membrane cleaning was performed daily. Three different cleaning solutions, containing SDS, SDS+EDTA and NaOH were compared. About 99% of the fouling resistance could be removed by rinsing the membrane with water. Flux recoveries (FRs) above 98% were achieved for all the three cleaning solutions after cleaning. No significant differences in FR were found between the cleaning solutions. The NaOH solution thus is a good economical option for cleaning RO spiral-wound membranes fouled with swine wastewater. Soaking the membrane for 3 days in permeate water at the end of each week further improved the FR. Furthermore, a fouling resistance model for predicting the fouling rate, permeate flux decay and cleaning cycle periods based on processing time and swine wastewater conductivity was developed.

  17. Prediction of the rejection of organic compounds (neutral and ionic) by nanofiltration and reverse osmosis membranes using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Ammi, Yamina; Khaouane, Latifa; Hanini, Salah [University of Medea, Medea (Algeria)

    2015-11-15

    This work investigates the use of neural networks in modeling the rejection processes of organic compounds (neutral and ionic) by nanofiltration and reverse osmosis membranes. Three feed-forward neural network (NN) models, characterized by a similar structure (eleven neurons for NN1 and NN2 and twelve neurons for NN3 in the input layer, one hidden layer and one neuron in the output layer), are constructed with the aim of predicting the rejection of organic compounds (neutral and ionic). A set of 956 data points for NN1 and 701 data points for NN2 and NN3 were used to test the neural networks. 80%, 10%, and 10% of the total data were used, respectively, for the training, the validation, and the test of the three models. For the most promising neural network models, the predicted rejection values of the test dataset were compared to measured rejections values; good correlations were found (R= 0.9128 for NN1, R=0.9419 for NN2, and R=0.9527 for NN3). The root mean squared errors for the total dataset were 11.2430% for NN1, 9.0742% for NN2, and 8.2047% for NN3. Furthermore, the comparison between the predicted results and QSAR models shows that the neural network models gave far better.

  18. Feasibility of municipal solid waste (MSW as energy sources for Saudi Arabia’s future Reverse osmosis (RO desalination plants

    Directory of Open Access Journals (Sweden)

    Agboola Phillips O.

    2016-12-01

    Full Text Available The Kingdom of Saudi Arabia (KSA generates between 1.4–1.75 kg/person/day of Municipal Solid Waste (MSW that accounts for over 16 million tons of MSW/year. The solid waste collected from different sources is dumped in landfills, thereby creating environmental concerns. In this paper, the potential of solid waste as an energy source (Waste to Energy (WTE for Reverse Osmosis (RO water purification was evaluated. The KSA is known for its acute fresh water shortages and uses desalination technology in meeting its daily water requirements; a process that is energy intensive. The evaluation of the energy content of MSW shows a potential to produce about 927 MW in 2015, based on a total mass burn, and about 1,692 MW in 2032. The MSW-WTE plants can produce about 1.5% of the targeted 120 GW of energy for 2032. For the R.O system, it will give approximately 16.8% of the daily fresh water needed for total mass burn and 2.4% with the recycling option.

  19. Effect of coagulation on treatment of municipal wastewater reverse osmosis concentrate by UVC/H2O2.

    Science.gov (United States)

    Umar, Muhammad; Roddick, Felicity; Fan, Linhua

    2014-02-15

    Disposal of reverse osmosis concentrate (ROC) is a growing concern due to potential health and ecological risks. Alum coagulation was investigated as pre-treatment for the UVC/H2O2 treatment of two high salinity ROC samples (ROC A and B) of comparable organic and inorganic content. Coagulation removed a greater fraction of the organic content for ROC B (29%) than ROC A (16%) which correlated well with the reductions of colour and A254. Although the total reductions after 60 min UVC/H2O2 treatment with and without coagulation were comparable, large differences in the trends of reduction were observed which were attributed to the different nature of the organic content (humic-like) of the samples as indicated by the LC-OCD analyses and different initial (5% and 16%) biodegradability. Coagulation and UVC/H2O2 treatment preferentially removed humic-like compounds which resulted in low reaction rates after UVC/H2O2 treatment of the coagulated samples. The improvement in biodegradability was greater (2-3-fold) during UVC/H2O2 treatment of the pre-treated samples than without pre-treatment. The target DOC residual (≤ 15 mg/L) was obtained after 30 and 20 min irradiation of pre-treated ROC A and ROC B with downstream biological treatment, corresponding to reductions of 55% and 62%, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Electrochemical oxidation of tramadol in low-salinity reverse osmosis concentrates using boron-doped diamond anodes.

    Science.gov (United States)

    Lütke Eversloh, Christian; Schulz, Manoj; Wagner, Manfred; Ternes, Thomas A

    2015-04-01

    The electrochemical treatment of low-salinity reverse osmosis (RO) concentrates was investigated using tramadol (100 μM) as a model substance for persistent organic contaminants. Galvanostatic degradation experiments using boron-doped diamond electrodes at different applied currents were conducted in RO concentrates as well as in ultra-pure water containing either sodium chloride or sodium sulfate. Kinetic investigations revealed a significant influence of in-situ generated active chlorine besides direct anodic oxidation. Therefore, tramadol concentrations decreased more rapidly at elevated chloride content. Nevertheless, reduction of total organic carbon (TOC) was found to be comparatively low, demonstrating that transformation rather than mineralization was taking place. Early stage product formation could be attributed to both direct and indirect processes, including demethylation, hydroxylation, dehydration, oxidative aromatic ring cleavage and halogenation reactions. The latter led to various halogenated derivatives and resulted in AOX (adsorbable organic halogens) formation in the lower mg/L-range depending on the treatment conditions. Characterisation of transformation products (TPs) was achieved via MS(n) experiments and additional NMR measurements. Based on identification and quantification of the main TPs in different matrices and on additional potentiostatic electrolysis, a transformation pathway was proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Reverse osmosis as a potential technique to improve antioxidant properties of fruit juices used for functional beverages.

    Science.gov (United States)

    Gunathilake, K D P P; Yu, Li Juan; Rupasinghe, H P Vasantha

    2014-04-01

    Reverse osmosis (RO) as a potential technique to improve the antioxidant properties of cranberry, blueberry and apple juices was evaluated for the formulation of a functional beverage. The effects of temperature (20-40 °C) and trans-membrane pressure (25-35 bars) on physico-chemical and antioxidant properties of fruit juices were evaluated to optimize the operating parameters for each fruit juice. There was no significant effect on any quality parameters of fruit juices under studied operating parameters of RO. However, total soluble solid, total acidity and colour (a(∗)) of the concentrated juices increased in proportion to their volumetric concentrations. Antioxidant capacity measured by FRAP assay of concentrated apple, blueberry and cranberry juice was increased by 40%, 34%, and 30%, respectively. LDL oxidation inhibition by concentrated blueberry and cranberry juice was increased up to 41% and 45%, respectively. The results suggest that RO can be used for enhancing the health promoting properties of fruit juices. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation.

    Science.gov (United States)

    Ben-Sasson, Moshe; Lu, Xinglin; Bar-Zeev, Edo; Zodrow, Katherine R; Nejati, Siamak; Qi, Genggeng; Giannelis, Emmanuel P; Elimelech, Menachem

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Effects of chemical agent injections on genotoxicity of wastewater in a microfiltration-reverse osmosis membrane process for wastewater reuse.

    Science.gov (United States)

    Tang, Fang; Hu, Hong-Ying; Wu, Qian-Yuan; Tang, Xin; Sun, Ying-Xue; Shi, Xiao-Lei; Huang, Jing-Jing

    2013-09-15

    With combined microfiltration (MF)/ultrafiltration (UF) and reverse osmosis (RO) process being widely used in municipal wastewater reclamation, RO concentrate with high level genotoxicity is becoming a potential risk to water environment. In this study, wastewater genotoxicity in a MF-RO process for municipal wastewater reclamation and also the effects of chemical agent injections were evaluated by SOS/umu genotoxicity test. The genotoxicity of RO concentrate ranged 500-559 μg 4-NQO (4-nitroquinoline-1-oxide)/L and 12-22 μg 4-NQO/mg DOC, was much higher than that of RO influent. Further research suggested that Kathon biocide was a key chemical agent associated with the genotoxicity increase. Kathon biocide used in RO system was highly genotoxic in vitro and Kathon biocide retained in RO system could contribute to a higher genotoxicity of RO concentrate. Hence, treatments for biocides before discharging are necessary. Chlorination of secondary effluent could significantly decrease the genotoxicity and increasing chlorine dosage could be an efficacious method to decrease the genotoxicity of RO concentrate. According to the result of the experiment, the dosage of chlorine in dual-membrane process could be set to about 2.5 mg Cl₂/L. The effect of antiscalant (2-phosphomobutane-1,2,4-tricarboxylic acid) was also investigated; it turned out to have no effect on genotoxicity. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. The Impact of Integrated Aquifer Storage and Recovery and Brackish Water Reverse Osmosis (ASRRO on a Coastal Groundwater System

    Directory of Open Access Journals (Sweden)

    Steven Eugenius Marijnus Ros

    2017-04-01

    Full Text Available Aquifer storage and recovery (ASR of local, freshwater surpluses is a potential solution for freshwater supply in coastal areas, as is brackish water reverse osmosis (BWRO of relatively shallow groundwater in combination with deeper membrane concentrate disposal. A more sustainable and reliable freshwater supply may be achieved by combining both techniques in one ASRRO system using multiple partially penetrating wells (MPPW. The impact of widespread use of ASRRO on a coastal groundwater system was limited based on regional groundwater modelling but it was shown that ASRRO decreased the average chloride concentration with respect to the autonomous scenario and the use of BWRO. ASRRO was successful in mitigating the local negative impact (saltwater plume formation caused by the deep disposal of membrane concentrate during BWRO. The positive impacts of ASRRO with respect to BWRO were observed in the aquifer targeted for ASR and brackish water abstraction (Aquifer 1, but foremost in the deeper aquifer targeted for membrane concentrate disposal (Aquifer 2. The formation of a horizontal freshwater barrier was found at the top of both aquifers, reducing saline seepage. The disposal of relatively fresh concentrate in Aquifer 2 led to brackish water outflow towards the sea. The net abstraction in Aquifer 1 enforced saltwater intrusion, especially when BWRO was applied. The conclusion of this study is that ASRRO can provide a sustainable alternative for BWRO.

  5. Reuse of olive mill effluents from two-phase extraction process by integrated advanced oxidation and reverse osmosis treatment.

    Science.gov (United States)

    Ochando-Pulido, J M; Hodaifa, G; Victor-Ortega, M D; Rodriguez-Vives, S; Martinez-Ferez, A

    2013-12-15

    In this work, complete reclamation of the olive mill effluents coming from a two-phase olive oil extraction process (OME-2) was studied on a pilot scale. The developed depuration procedure integrates an advanced oxidation process based on Fenton's reagent (secondary treatment) coupled with a final reverse osmosis (RO) stage (purification step). The former aims for the removal of the major concentration of refractory organic pollutants present in OME-2, whereas the latter provides efficient purification of the high salinity. Complete physicochemical composition of OME-2 after the secondary treatment was examined, including the particle size distribution, organic matter gradation and bacterial growth, in order to assess the selection of the membrane and its fouling propensity. Hydrodynamics and selectivity of the membrane were accurately modelized. Upon optimization of the hydrodynamic conditions, the RO membrane showed stable performance and fouling problems were satisfactorily overcome. Steady-state permeate flux equal to 21.1 L h(-1)m(-2) and rejection values up to 99.1% and 98.1% of the organic pollutants and electroconductivity were respectively attained. This ensured parametric values below standard limits for reuse of the regenerated effluent, e.g. in the olives washing machines, offering the possibility of closing the loop and thus rending the production process environmentally friendly. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Aerobic SMBR/reverse osmosis system enhanced by Fenton oxidation for advanced treatment of old municipal landfill leachate.

    Science.gov (United States)

    Zhang, Guoliang; Qin, Lei; Meng, Qin; Fan, Zheng; Wu, Dexin

    2013-08-01

    A novel combined process of Fenton oxidation, submerged membrane bioreactor (SMBR) and reverse osmosis (RO) was applied as an appropriate option for old municipal landfill leachate treatment. Fenton process was designed to intensively solve the problem of non-biodegradable organic pollutant removal and low biodegradability of leachate, although the removal of ammonia-nitrogen was similar to 10%. After SMBR treatment, it not only presented a higher removal efficiency of organics, but also exhibited high ammonia-nitrogen removal of 80% on average. The variation of extracellular polymeric substance (EPS) content, zeta potential, and particle size of flocs after Fenton effluent continually fed in SMBR was found to be benefit for alleviating membrane fouling. Finally, three kinds of RO membranes (RE, CPA, and BW) were applied to treat SMBR effluents and successfully met wastewater re-utilization requirement. Compared with simple RO process, the troublesome membrane fouling can be effectively reduced in the combined process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Reverse osmosis pretreatment method for toxicity assessment of domestic wastewater using Vibrio qinghaiensis sp.-Q67.

    Science.gov (United States)

    Ma, Xiaoyan Y; Wang, Xiaochang C; Hao Ngo, Huu; Guo, Wenshan; Wu, Maoni N; Wang, Na

    2013-11-01

    Luminescent bacterial test is a fast and sensitive method for acute toxicity assessment of water and wastewater. In this study, an improved toxicity testing method was developed using the freshwater luminescent bacteria Vibrio qinghaiensis sp.-Q67 that involved pretreatment of water samples with reverse osmosis (RO) to eliminate the interferences caused by nutrients in concentrated samples and to improve the reliability and sensitivity of the analysis. Because water samples contain low concentrations of several target toxic substances, rapid acute toxicity testing method that is commonly employed does not achieve enough sensitivity. The proposed RO pretreatment could effectively enrich organic and inorganic substances in water samples to enable a more effective and sensitive toxicity evaluation. The kinetic characteristics of toxicity of raw sewage and secondary effluent were evaluated based on the relative luminescence unit (RLU) curves and time-concentration-effect surfaces. It was observed that when the exposure time was prolonged to 8-h or longer, the bacteria reached the logarithmic growth stage. Hence, the stimulating effects of the coexisting ions (such as Na(+), K(+), NO3(-)) in the concentrated samples could be well eliminated. A 10-h exposure time in proposed Q67 test was found to quantitatively evaluate the toxicity of the organic and inorganic pollutants in the RO-concentrated samples. © 2013 Elsevier Inc. All rights reserved.

  8. Fabrication of semi-aromatic polyamide/spherical mesoporous silica nanocomposite reverse osmosis membrane with superior permeability

    Science.gov (United States)

    Li, Qiang; Yu, Hui; Wu, Feiyang; Song, Jie; Pan, Xianhui; Zhang, Meng

    2016-02-01

    Semi-aromatic polyamide (SAP)/spherical mesoporous silica nanocomposite reverse osmosis (RO) membrane was successfully fabricated using m-phenylene diamine aqueous solution and cyclohexane-1,3,5-tricarbonyl chloride/mesoporous-silica-sphere (MSS) organic solution as main raw materials. The experimental suggests that the microstructures and surface features are significantly different from those of the contrast samples (the full- and semi-aromatic polyamide membranes), including the surface morphology, polymer framework structure, surface charge density, hydrophilicity, and the thickness of barrier layer. It was observed that many MSSs with ca. 1.5 nm of pore size are evenly embedded on the surface of the fabricated SAP/MSS RO membrane. Furthermore, the separation performance testing results indicate that the permeabilities range from 62.53 to 72.73 L/m2 h with the increase of the introduced MSSs from 0.02 to 0.08 w/v % under 1.5 MPa operating pressure and 2000 mg/L NaCl solution, which is obviously better than the contrast samples. Simultaneously, their salt rejections can be still maintained at a comparable level (94.78-91.46%). The excellent separation performance of the nanocomposite RO membrane is closely related to the higher-freedom-degree semi-aromatic framework, the incorporation of MSSs, the improved surface hydrophilicity, the thinner barrier layer, and the enhanced surface negative charge density.

  9. Assessment of nanofiltration and reverse osmosis potentialities to recover metals, sulfuric acid, and recycled water from acid gold mining effluent.

    Science.gov (United States)

    Ricci, Bárbara C; Ferreira, Carolina D; Marques, Larissa S; Martins, Sofia S; Amaral, Míriam C S

    This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (<88%) when conducted in pH values higher than 1. Thus, sequential use of NF and RO was proved to be a promising treatment for sulfuric acid solutions contaminated by metals, such as POX effluent. In this context, a purified acid stream could be recovered in NF permeate, which could be further concentrated in RO. Recovered acid stream could be reused in the gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water.

  10. Diminished swelling of cross-linked aromatic oligoamide surfaces revealing a new fouling mechanism of reverse-osmosis membranes.

    Science.gov (United States)

    Ying, Wang; Kumar, Rajender; Herzberg, Moshe; Kasher, Roni

    2015-06-02

    Swelling of the active layer of reverse osmosis (RO) membranes has an important effect on permeate water flux. The effects of organic- and biofouling on the swelling of the RO membrane active layer and the consequent changes of permeate flux are examined here. A cross-linked aromatic oligoamide film that mimics the surface chemistry of an RO polyamide membrane was synthesized stepwise on gold-coated surfaces. Foulant adsorption to the oligoamide film and its swelling were measured with a quartz crystal microbalance, and the effects of fouling on the membrane's performance were evaluated. The foulants were extracellular polymeric substances (EPS) extracted from fouled RO membranes and organic compounds of ultrafiltration permeate (UFP) from a membrane bioreactor used to treat municipal wastewater. The adsorbed foulants affected the swelling of the cross-linked oligoamide film differently. EPS had little effect on the swelling of the oligoamide film, whereas UFP significantly impaired swelling. Permeate flux declined more rapidly under UFP fouling than it did under EPS. Foulant adsorption was shown to diminish swelling of the aromatic oligoamide surfaces. Among the already known RO membrane fouling mechanisms, a novel RO fouling mechanism is proposed, in which foulant-membrane interactions hinder membrane swelling and thus increase hydraulic resistance.

  11. Electrochemical treatment of reverse osmosis concentrate on boron-doped electrodes in undivided and divided cell configurations.

    Science.gov (United States)

    Bagastyo, Arseto Y; Batstone, Damien J; Kristiana, Ina; Escher, Beate I; Joll, Cynthia; Radjenovic, Jelena

    2014-08-30

    An undivided electrolytic cell may offer lower electrochlorination through reduction of chlorine/hypochlorite at the cathode. This study investigated the performance of electrooxidation of reverse osmosis concentrate using boron-doped diamond electrodes in membrane-divided and undivided cells. In both cell configurations, similar extents of chemical oxygen demand and dissolved organic carbon removal were obtained. Continuous formation of chlorinated organic compounds was observed regardless of the membrane presence. However, halogenation of the organic matter did not result in a corresponding increase in toxicity (Vibrio fischeri bioassay performed on extracted samples), with toxicity decreasing slightly until 10AhL(-1), and generally remaining near the initial baseline-toxicity equivalent concentration (TEQ) of the raw concentrate (i.e., ∼2mgL(-1)). The exception was a high range toxicity measure in the undivided cell (i.e., TEQ=11mgL(-1) at 2.4AhL(-1)), which rapidly decreased to 4mgL(-1). The discrepancy between the halogenated organic matter and toxicity patterns may be a consequence of volatile and/or polar halogenated by-products formed in oxidation by OH electrogenerated at the anode. The undivided cell exhibited lower energy compared to the divided cell, 0.25kWhgCOD(-1) and 0.34kWhgCOD(-1), respectively, yet it did not demonstrate any improvement regarding by-products formation.

  12. Fouling characteristics of reverse osmosis membranes at different positions of a full-scale plant for municipal wastewater reclamation.

    Science.gov (United States)

    Tang, Fang; Hu, Hong-Ying; Sun, Li-Juan; Sun, Ying-Xue; Shi, Na; Crittenden, John C

    2016-03-01

    Membrane fouling is an important shortcoming limiting the efficiency and wide application of reverse osmosis (RO) technology. In this paper, RO membranes in a full-scale municipal wastewater reclamation plant were autopsied. From the lead to tail position RO membranes in RO system, both of organic and inorganic matters on membranes reduced gradually. The higher ion products in RO concentrate didn't result in more serious inorganic scaling on the last position RO membranes, which was contrast with some other researches. Fe, Ca and Mg were major inorganic elements. Fe had a relatively low concentration in RO influent but the highest content on membranes. However, there was no specific pretreatment in terms of Fe removal. Ca and Mg scaling was controlled by the antiscalants injected. Organic fouling (75.0-84.5% of dry weights) was major problem on RO membranes due to the large amount of dissolved organic matters in secondary effluent as raw water. Hydrophilic acid (HIA, 48.0% of total DOC), hydrophobic acid (HOA, 23.6%) and hydrophobic neutral (HON, 19.0%) fraction was largest among the six fractions in RO influent, while HON (38.2-51.1%) and HOA (22.1-26.1%) tended to accumulate on membranes in higher quantities. Monitoring HON and HOA might help to forecast organic fouling.

  13. Removal of nitrogen compounds from landfill leachate using reverse osmosis with leachate stabilization in a buffer tank.

    Science.gov (United States)

    Talalaj, Izabela Anna

    2015-01-01

    In this paper, a removal of nitrogen compounds from a landfill leachate during reverse osmosis (RO) was evaluated. The treatment facility consists of a buffer tank and a RO system. The removal rate of N─NH4, [Formula: see text] and [Formula: see text] in the buffer tank reached 14%, 91% and 41%, respectively. The relatively low concentration of organic carbon limits N─NH4 oxidation in the buffer tank. The removal rate for the total organic nitrogen (TON) was 47%. The removal rate in RO was 99% for [Formula: see text], 84.1% for [Formula: see text] and 41% for [Formula: see text]. The accumulation of [Formula: see text] may be the result of a low pH, which before the RO process is reduced to a value of 6.0-6.5. Besides it, the cause for a low removal rate of the [Formula: see text] in the buffer tank and during RO may be free ammonia, which can inhibit the [Formula: see text] oxidation. The removal rates of total inorganic nitrogen and TON in the RO treatment facility were similar being 99% and 98.5%, respectively.

  14. Boron as a surrogate for N-nitrosodimethylamine rejection by reverse osmosis membranes in potable water reuse applications.

    Science.gov (United States)

    Tu, Kha L; Fujioka, Takahiro; Khan, Stuart J; Poussade, Yvan; Roux, Annalie; Drewes, Jörg E; Chivas, Allan R; Nghiem, Long D

    2013-06-18

    The results of this study reveal a strong linear correlation (R(2) = 0.95) between the rejections of boron and N-nitrosodimethylamine (NDMA) by six different reverse osmosis (RO) membranes, suggesting that boron can be used as a surrogate for NDMA rejection. This proposal is based on the premise that the rejection of both boric acid and NDMA is governed by steric hindrance and that they have similar molecular dimensions. The concept proposed here is shown to be valid at pH 8 or below where boron exists as the neutral boric acid species and NDMA is also a neutral solute. Observed changes in the rejections of these two species, as a function of permeate fluxes and feed solution temperatures, were also almost identical. Boron rejection increased from 21 to 79%, and the correlation coefficient of the linear regression between boron and NDMA rejections was 0.99 as the permeate flux increased from 5 to 60 L m(-2)h(-1). Similarly, a linear correlation between boron and NDMA rejections was observed as the feed solution temperature increased from 10 to 40 °C. This linear correlation was also validated in a tertiary treated effluent matrix.

  15. The Development of a Renewable-Energy-Driven Reverse Osmosis System for Water Desalination and Aquaculture Production

    Institute of Scientific and Technical Information of China (English)

    Clark C K Liu

    2013-01-01

    Water and energy are closely linked natural resources-the transportation, treatment, and distribution of water depends on low-cost energy;while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis (RO) system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of (1) a wind-driven pumping subsystem, (2) a pressure-driven RO membrane desalination subsystem, and (3) a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-1 or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids (TDS) of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-1 or less. Results of the pilot experiments also indicated that the system can remove up to 97%of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56%of the freshwater supply for fish pond operation.

  16. Anthocyanin and flavonoid production from Perilla frutescens: pilot plant scale processing including cross-flow microfiltration and reverse osmosis.

    Science.gov (United States)

    Meng, Linghua; Lozano, Yves; Bombarda, Isabelle; Gaydou, Emile; Li, Bin

    2006-06-14

    Extraction and concentration at a pilot plant scale of anthocyanins and flavonoids from Perilla frutescens var. frutescens harvested in the Guangzhou area of China were investigated. The study of extraction efficiency using mineral acids and organic acids showed that 0.01 mol/L nitric acid was the most suitable to extract flavonoids from this slightly red leaf cultivar. The red extract contained 12 mg/L (as cyanidin equivalent) anthocyanins and other flavones. The multistep process included cross-flow microfiltration (CFM) with a ceramic type membrane, reverse osmosis (RO), and rotating evaporation (RE). The filtration fluxes were high and constant for CFM (150 L/h/m2 at 0.6 b) and for RO (22 L/h/m2 at 40 b). The red extract was concentrated 9.4 times by RO and then 5.4 times by RE. It contained 422 mg/L anthocyanins, representing 77% of the total extracted anthocyanin. The proportion of flavonoids was found unchanged during processing. The concentrated extract showed a pH of 2.7, and its free acidity was found to be 46% of the acidity added for extraction, because of the buffering capacity of the extract. At the concentration level reached, a crystallized deposit occurred and was identified as tartrate.

  17. Pharmaceuticals and pesticides in reclaimed water: Efficiency assessment of a microfiltration-reverse osmosis (MF-RO) pilot plant.

    Science.gov (United States)

    Rodriguez-Mozaz, Sara; Ricart, Marta; Köck-Schulmeyer, Marianne; Guasch, Helena; Bonnineau, Chloe; Proia, Lorenzo; de Alda, Miren Lopez; Sabater, Sergi; Barceló, Damià

    2015-01-23

    Water reuse is becoming a common practice in several areas in the world, particularly in those impacted by water scarcity driven by climate change and/or by rising human demand. Since conventional wastewater treatment plants (WWTPs) are not able to efficiently remove many organic contaminants and pathogens, more advanced water treatment processes should be applied to WWTP effluents for water reclamation purposes. In this work, a pilot plant based on microfiltration (MF) followed by reverse osmosis (RO) filtration was applied to the effluents of an urban WWTP. Both the WWTP and the pilot plant were investigated with regards to the removal of a group of relevant contaminants widely spread in the environment: 28 pharmaceuticals and 20 pesticides. The combined treatment by the MF-RO system was able to quantitatively remove the target micropollutants present in the WWTP effluents to values either in the low ng/L range or below limits of quantification. Monitoring of water quality of reclaimed water and water reclamation sources is equally necessary to design the most adequate treatment procedures aimed to water reuse for different needs.

  18. Beneficial phosphate recovery from reverse osmosis (RO) concentrate of an integrated membrane system using polymeric ligand exchanger (PLE).

    Science.gov (United States)

    Kumar, Manish; Badruzzaman, Mohammad; Adham, Samer; Oppenheimer, Joan

    2007-05-01

    Phosphorus (P) discharge to surface water is a major environmental problem. Wastewater treatment is targeted towards removal of this nutrient to prevent degradation of surface water. Integrated membrane systems (IMS) are increasingly being considered for wastewater reclamation, and provide excellent removal of P compounds. However, reverse osmosis (RO), which forms an integral part of these IMSs, concentrates most dissolved substances including P-species such as phosphates in the RO waste stream. In this study, removal of phosphate from this stream using polymeric ligand exchange (PLE) resins was investigated. Further, the possibility of phosphate recovery through struvite (MgNH(4)PO(4).6H(2)O) precipitation was tested. Struvite has been promoted as a slow release fertilizer in recent years. This study demonstrates that PLEs can be successfully used to remove phosphate from RO-concentrate, and to recover more than 85% of the adsorbed phosphorus from the exhausted media and precipitated as a beneficial product (struvite). The approach, presented in this study, suggests advantages of providing economic benefit from a waste product (RO) while avoiding phosphorus discharge to the environment.

  19. Dynamics of biofilm formation under different nutrient levels and the effect on biofouling of a reverse osmosis membrane system.

    Science.gov (United States)

    Chen, Xi; Suwarno, Stanislaus Raditya; Chong, Tzyy Haur; McDougald, Diane; Kjelleberg, Staffan; Cohen, Yehuda; Fane, Anthony G; Rice, Scott A

    2013-01-01

    Pseudomonas aeruginosa PAO1 wild type and a mucoid derivative (FRD1) which over produces alginate were used to foul reverse osmosis (RO) membranes. When operated at a constant flux, biofilm formation on the RO membrane resulted in a slow rise in transmembrane pressure (TMP) of 22% for the initial four days of operation, followed by a sharp increase of 159% over the following two days. The initial slow increase in TMP was probably due to the formation of a biofilm on the membrane surface, which then accelerated the rate of biofouling through the effect of concentration polarization. At later stages of operation, most of the bacterial biomass consisted of dead cells. The amount of extracellular polymeric substances appeared to correlate positively with the number of dead cells. The results indicate that prolonging the initial stage of slow TMP increase and avoiding the latter stage of accelerated TMP increase would provide a sustainable operation of the RO system. These results suggest that nutrient limitation could reduce biofilm accumulation and delay the increase in TMP.

  20. Effect of conventional chemical treatment on the microbial population in a biofouling layer of reverse osmosis systems.

    Science.gov (United States)

    Bereschenko, L A; Prummel, H; Euverink, G J W; Stams, A J M; van Loosdrecht, M C M

    2011-01-01

    The impact of conventional chemical treatment on initiation and spatiotemporal development of biofilms on reverse osmosis (RO) membranes was investigated in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The flow cells got the same feed (extensively pre-treated fresh surface water) and operational conditions (temperature, pressure and membrane flux) as the full-scale installation. With regular intervals both the full-scale RO membrane modules and the flow cells were cleaned using conventional chemical treatment. For comparison some flow cells were not cleaned. Sampling was done at different time periods of flow cell operation (i.e., 1, 5, 10 and 17 days and 1, 3, 6 and 12 months). The combination of molecular (FISH, DGGE, clone libraries and sequencing) and microscopic (field emission scanning electron, epifluorescence and confocal laser scanning microscopy) techniques made it possible to thoroughly analyze the abundance, composition and 3D architecture of the emerged microbial layers. The results suggest that chemical treatment facilitates initiation and subsequent maturation of biofilm structures on the RO membrane and feed-side spacer surfaces. Biofouling control might be possible only if the cleaning procedures are adapted to effectively remove the (dead) biomass from the RO modules after chemical treatment.

  1. Culturable bacterial diversity from a feed water of a reverse osmosis system, evaluation of biofilm formation and biocontrol using phages.

    Science.gov (United States)

    Belgini, D R B; Dias, R S; Siqueira, V M; Valadares, L A B; Albanese, J M; Souza, R S; Torres, A P R; Sousa, M P; Silva, C C; De Paula, S O; Oliveira, V M

    2014-10-01

    Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems.

  2. Reverse osmosis followed by activated carbon filtration for efficient removal of organic micropollutants from river bank filtrate.

    Science.gov (United States)

    Kegel, F Schoonenberg; Rietman, B M; Verliefde, A R D

    2010-01-01

    Drinking water utilities in Europe are faced with a growing presence of organic micropollutants in their water sources. The aim of this research was to assess the robustness of a drinking water treatment plant equipped with reverse osmosis and subsequent activated carbon filtration for the removal of these pollutants. The total removal efficiency of 47 organic micropollutants was investigated. Results indicated that removal of most organic micropollutants was high for all membranes tested. Some selected micropollutants were less efficiently removed (e.g. the small and polar NDMA and glyphosate, and the more hydrophobic ethylbenzene and napthalene). Very high removal efficiencies for almost all organic micropollutants by the subsequent activated carbon, fed with the permeate stream of the RO element were observed except for the very small and polar NDMA and 1,4-dioxane. RO and subsequent activated carbon filtration are complementary and their combined application results in the removal of a large part of these emerging organic micropollutants. Based on these experiments it can be concluded that the robustness of a proposed treatment scheme for the drinking water treatment plant Engelse Werk is sufficiently guaranteed.

  3. High-performance polyamide thin-film-nanocomposite reverse osmosis membranes containing hydrophobic zeolitic imidazolate framework-8

    KAUST Repository

    Duan, Jintang

    2015-02-01

    A hydrophobic, hydrothermally stable metal-organic framework (MOF) - zeolitic imidazolate framework-8 (ZIF-8) was successfully incorporated into the selective polyamide (PA) layer of thin-film nanocomposite (TFN) membranes for water desalination. The potential advantages of ZIF-8 over classic hydrophilic zeolite used in TFNs include: i) theoretically faster water transport within the framework and ii) better compatibility with the PA matrix. The TFN membranes were characterized with SEM, TEM, AFM, XPS, water contact angle measurements and reverse osmosis tests under 15.5bar hydraulic pressure with 2000ppm NaCl solution. Lab-made, nano-sized (~200nm) ZIF-8 increased water permeance to 3.35±0.08L/m2·h·bar at 0.4% (w/v) loading, 162% higher than the pristine PA membranes; meanwhile, high NaCl rejection was maintained. The TFN surface was less crosslinked and more hydrophilic than that of the pristine PA. A filler encapsulation mechanism was proposed for the effects of filler on TFN membrane surface morphology and properties. This study experimentally verified the potential use of ZIF-8 in advanced TFN RO membranes.

  4. Fabrication of tethered carbon nanotubes in cellulose acetate/polyethylene glycol-400 composite membranes for reverse osmosis.

    Science.gov (United States)

    Sabir, Aneela; Shafiq, Muhammad; Islam, Atif; Sarwar, Afsheen; Dilshad, Muhammad Rizwan; Shafeeq, Amir; Zahid Butt, Muhammad Taqi; Jamil, Tahir

    2015-11-01

    In this study pristine multi-walled carbon nanotubes (MWCNTs) were surface engineered (SE) in strong acidic medium by oxidation purification method to form SE-MWCNT. Five different amount of SE-MWCNT ranging from 0.1 to 0.5 wt% were thoroughly and uniformly dispersed in cellulose acetate/polyethylene glycol (CA/PEG400) polymer matrix during synthesis of membrane by dissolution casting method. The structural analysis, surface morphology and roughness was carried out by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively, which showed that the dispersed SE-MWCNT was substantially tethered in CA/PEG400 polymer matrix membrane. The thermogravimetric analysis (TGA) of membranes also suggested some improvement in thermal properties with the addition of SE-MWCNT. Finally, the performance of these membranes was assessed for suitability in drinking water treatment. The permeation flux and salt rejection were determined by using indigenously fabricated reverse osmosis pilot plant with 1000 ppm NaCl feed solution. The results showed that the tethered SE-MWCNT/CA/PEG400 polymer matrix membrane, with strong SE-MWCNTs/polymer matrix interaction, improved the salt rejection performance of the membrane with the salt rejection of 99.8% for the highest content of SE-MWCNT.

  5. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation

    KAUST Repository

    Ben-Sasson, Moshe

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. © 2014 Elsevier Ltd.

  6. Highly and Stably Water Permeable Thin Film Nanocomposite Membranes Doped with MIL-101 (Cr Nanoparticles for Reverse Osmosis Application

    Directory of Open Access Journals (Sweden)

    Yuan Xu

    2016-10-01

    Full Text Available A hydrophilic, hydrostable porous metal organic framework (MOF material-MIL-101 (Cr was successfully doped into the dense selective polyamide (PA layer on the polysulfone (PS ultrafiltration (UF support to prepare a new thin film nanocomposite (TFN membrane for water desalination. The TFN-MIL-101 (Cr membranes were characterized by SEM, AFM, XPS, wettability measurement and reverse osmosis (RO test. The porous structures of MIL-101 (Cr can establish direct water channels in the dense selective PA layer for water molecules to transport through quickly, leading to the increasing water permeance of membranes. With good compatibility between MIL-101 (Cr nanoparticles and the PA layer, the lab made TFN-MIL-101 (Cr membranes integrated tightly and showed a high NaCl salt rejection. MIL-101 (Cr nanoparticles increased water permeance to 2.2 L/m2·h·bar at 0.05 w/v % concentration, 44% higher than the undoped PA membranes; meanwhile, the NaCl rejection remained higher than 99%. This study experimentally verified the potential use of MIL-101 (Cr in advanced TFN RO membranes, which can be used in the diversified water purification field.

  7. 4-Dimethylaminopyridine promoted interfacial polymerization between hyperbranched polyesteramide and trimesoyl chloride for preparing ultralow-pressure reverse osmosis composite membrane.

    Science.gov (United States)

    Qin, Jiaxu; Lin, Saisai; Song, Shuqin; Zhang, Lin; Chen, Huanlin

    2013-07-24

    We have presented a concept of ultralow-pressure reverse osmosis membrane based on hyperbranched polyesteramide through interfacial reaction promoted by pyridine derivate. In this strategy, a key catalyst of 4-dimethylaminopyridine, which can both eliminate the steric hindrance of acyl transfer reaction and facilitate the phase transfer in interfacial polymerization, is adopted to drive the formation of a thin film composite membrane from the hyperbranched polyesteramide and trimesoyl chloride. The results of the characterization demonstrate that a dense, rough, and hydrophilic active layer with a thickness of about 100 nm is formed when the 4-dimethylaminopyridine catalyst is used. The salt rejections for Na2SO4, NaCl, and MgSO4 of the as-prepared composite membrane are higher than 92%, especially for Na2SO4 with 98% rejection. The water fluxes reach about 30-40 L·m(-2)·h(-1) even at an operation pressure of 0.6 MPa. The membrane exhibits good chlorine-resistance ability but poor resistance abilities to acidic and alkaline solutions in the physical-chemical stability experiment. It is also found that the resultant membrane possesses excellent separation performance for PEG-200, showing a promising way to separate small organic molecules from water.

  8. Advanced oxidation of iodinated X-ray contrast media in reverse osmosis brines: the influence of quenching.

    Science.gov (United States)

    Azerrad, Sara P; Gur-Reznik, Shirra; Heller-Grossman, Lilly; Dosoretz, Carlos G

    2014-10-01

    Among the main restrictions for the implementation of advanced oxidation processes (AOPs) for removal of micropollutants present in reverse osmosis (RO) brines of secondary effluents account the quenching performed by background organic and inorganic constituents. Natural organic matter (NOM) and soluble microbial products (SMP) are the main effluent organic matter constituents. The inorganic fraction is largely constituted by chlorides and bicarbonate alkalinity with sodium and calcium as main counterions. The quenching influence of these components, separately and their mixture, in the transformation of model compounds by UVA/TiO2 was studied applying synthetic brines solutions mimicking 2-fold concentrated RO secondary effluents brines. The results were validated using fresh RO brines. Diatrizoate (DTZ) and iopromide (IOPr) were used as model compound. They have been found to exhibit relative high resistance to oxidation process and therefore represent good markers for AOPs techniques. Under the conditions applied, oxidization of DTZ in the background of RO brines was strongly affected by quenching effects. The major contribution to quenching resulted from organic matter (≈70%) followed by bicarbonate alkalinity (≈30%). NOM displayed higher quenching than SMP in spite of its relative lower concentration. Multivalent cations, i.e., Ca(+2), were found to decrease effectiveness of the technique due to agglomeration of the catalyst. However this influence was lowered in presence of NOM. Different patterns of transformation were found for each model compound in which a delayed deiodination was observed for iopromide whereas diatrizoate oxidation paralleled deiodination.

  9. Evaluation of contaminant removal of reverse osmosis and advanced oxidation in full-scale operation by combining passive sampling with chemical analysis and bioanalytical tools.

    Science.gov (United States)

    Escher, Beate I; Lawrence, Michael; Macova, Miroslava; Mueller, Jochen F; Poussade, Yvan; Robillot, Cedric; Roux, Annalie; Gernjak, Wolfgang

    2011-06-15

    Advanced water treatment of secondary treated effluent requires stringent quality control to achieve a water quality suitable for augmenting drinking water supplies. The removal of micropollutants such as pesticides, industrial chemicals, endocrine disrupting chemicals (EDC), pharmaceuticals, and personal care products (PPCP) is paramount. As the concentrations of individual contaminants are typically low, frequent analytical screening is both laborious and costly. We propose and validate an approach for continuous monitoring by applying passive sampling with Empore disks in vessels that were designed to slow down the water flow, and thus uptake kinetics, and ensure that the uptake is only marginally dependent on the chemicals' physicochemical properties over a relatively narrow molecular size range. This design not only assured integrative sampling over 27 days for a broad range of chemicals but also permitted the use of a suite of bioanalytical tools as sum parameters, representative of mixtures of chemicals with a common mode of toxic action. Bioassays proved to be more sensitive than chemical analysis to assess the removal of organic micropollutants by reverse osmosis, followed by UV/H₂O₂ treatment, as many individual compounds fell below the quantification limit of chemical analysis, yet still contributed to the observed mixture toxicity. Nonetheless in several cases, the responses in the bioassays were also below their quantification limits and therefore only three bioassays were evaluated here, representing nonspecific toxicity and two specific end points for estrogenicity and photosynthesis inhibition. Chemical analytical techniques were able to quantify 32 pesticides, 62 PCPPs, and 12 EDCs in reverse osmosis concentrate. However, these chemicals could explain only 1% of the nonspecific toxicity in the Microtox assay in the reverse osmosis concentrate and 0.0025% in the treated water. Likewise only 1% of the estrogenic effect in the E-SCREEN could be

  10. Carbon Dioxide Nucleation as a Novel Cleaning Method for Sodium Alginate Fouling Removal from Reverse Osmosis Membranes desalination

    KAUST Repository

    Alnajjar, Heba

    2017-05-01

    The use of Reverse osmosis (RO) membranes have been significantly increasing in water desalination, and the main operational obstacle in RO desalination plants is membrane fouling. Among other solutes, dissolved biopolymers, such as polysaccharides can lead to severe membrane fouling especially with the addition of calcium ions because of the complexation formation between the surface of membrane and foulants materials. However, this complexation can also take place in the feed bulk, resulting in foulants aggregates formation. Although there are some physical techniques that can maintain the membrane performance without reducing its lifetime, only chemical cleanings are still commonly used in RO plants. In this study, a novel cleaning method is proposed to restore the membrane performance by removing the deposited foulants without reducing the membrane lifetime. The cleaning method is based on using water saturated with dissolved CO2 gas, and its principle is based on producing spontaneous CO2 bubbles due to local pressure difference leading to nucleation of bubbles throughout the membrane surface, especially at nucleation sites, which improve the cleaning efficiency. Alginic acid sodium salt was used as a model of polysaccharides foulants in presence of different concentrations of NaCl and calcium ions aiming to enhance membrane fouling, and then CO2 cleaning solution efficiency, in terms flux recovery (FR), was tested under different operating conditions and compared to other cleaning methods. Average FR of 20%±3, 25%±3 and 80%±3 for MilliQ water, a cleaning solution at pH4, and CO2 solution at 6 bar, 0.17 m/s, and 23 ̊C ±0.2 for 6 minutes were obtained, respectively. The efficiency of this novel cleaning method was also compared to direct osmosis overnight, and the average flux was comparable (about 60%±3), though that the cleaning time was significantly different. Various calcium concentrations (0-10 mM) were added in the alginate solution to study the

  11. Co-generation project for the Combined Cycle Power Plant President Juarez Rosarito and a reverse osmosis desalting plant; Proyecto de cogeneracion para la planta de ciclo combinado Presidente Juarez Rosarito y una planta desaladora de osmosis inversa

    Energy Technology Data Exchange (ETDEWEB)

    Beltran Mora, Hector; Espindola Hernandez, Salvador [Universidad NAcional Autonoma de Mexico (UNAM), Mexico, D.F. (Mexico)

    2006-11-15

    In this work a technical and economical analysis of the installation of a reverse osmosis desalting plant connected to a power station that uses the combined cycle technology under a co-generation scheme is presented: production of electricity and water. The operation program of the desalting power station will be determined by the demand of energy of the combined cycle power station; the proposal is that the desalting plant operates in the hours of low load of the power station and shuts down at the peak hours of electrical energy demand. So that this study is representative, the demand curves of electric energy of the units of combined cycle of Central President Juarez Rosarito of the Comision Federal de Electricidad (CFE) have been taken and updated the data of the reverse osmosis desalting plants that are available at the moment in the market. As basis of the study the level costs will be determined so much as the electrical energy generated by the power station of combined cycle, operating inside and outside of a co-generation scheme and the costs made level for the water produced by the reverse osmosis plant under two assumptions: the first one is buying the electrical energy from CFE and the second one considering that the CFE is the owner of the desalting plant and therefore the cost of electrical energy to desalting the plant is zero. This work shows the economic impacts on the costs of the generation of electrical energy and on those of the desalted water in a co-generation scheme. The results shown in this study can be considered for the future planning in the construction of desalting plants to supply of water in the Northwestern zones of the country where serious problems of water shortage exist. [Spanish] En este trabajo se presenta un analisis tecnico y economico de la instalacion de una planta desaladora de osmosis inversa acoplada a una central de generacion de energia electrica que utiliza la tecnologia de ciclo combinado bajo un esquema de

  12. Development of wet-dry reversible reverse osmosis membrane with high performance from cellulose acetate and cellulose triactate blend

    NARCIS (Netherlands)

    Vasarhelyi, K.; Ronner, J.A.; Mulder, M.H.V.; Smolders, C.A.

    1987-01-01

    Wet-dry reversible membrane were prepared bt a two-step coagulation procedure. A cast film containing a blend of cellulose triacetate as polymers, dioxane and acetone as solvents and maleic acid and methanol as additives was immersed consecutively in two aqueous coagulation baths, the first bath bei

  13. Performance of electrodialysis reversal and reverse osmosis for reclaiming wastewater from high-tech industrial parks in Taiwan: A pilot-scale study.

    Science.gov (United States)

    Yen, Feng-Chi; You, Sheng-Jie; Chang, Tien-Chin

    2017-02-01

    Wastewater reclamation is considered an absolute necessity in Taiwan, as numerous industrial parks experience water shortage. However, the water quality of secondary treated effluents from sewage treatment plants generally does not meet the requirements of industrial water use because of the high inorganic constituents. This paper reports experimental data from a pilot-plant study of two treatment processes-(i) fiber filtration (FF)-ultrafiltration (UF)-reverse osmosis (RO) and (ii) sand filtration (SF)-electrodialysis reversal (EDR)-for treating industrial high conductivity effluents from the Xianxi wastewater treatment plant in Taiwan. The results demonstrated that FF-UF was excellent for turbidity removal and it was a suitable pretreatment process for RO. The influence of two membrane materials on the operating characteristics and process stability of the UF process was determined. The treatment performance of FF-UF-RO was higher than that of SF-EDR with an average desalination rate of 97%, a permeate conductivity of 272.7 ± 32.0, turbidity of 0.183 ± 0.02 NTU and a chemical oxigen demand of <4.5 mg/L. The cost analysis for both processes in a water reclamation plant of 4000 m(3)/d capacity revealed that using FF-UF-RO had a lower treatment cost than using SF-EDR, which required activated carbon filtration as a post treatment process. On the basis of the results in this study, the FF-UF-RO system is recommended as a potential process for additional applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Effect of silica fouling on the removal of pharmaceuticals and personal care products by nanofiltration and reverse osmosis membranes.

    Science.gov (United States)

    Lin, Yi-Li; Chiou, Jheng-Hong; Lee, Chung-Hsiang

    2014-07-30

    In this study, one reverse osmosis (XLE) and two nanofiltration (NF90 and NF270) membranes were fouled by silica to evaluate its effect on the flux decline as well as the removal of six pharmaceuticals and personal care products (PPCPs) including carbamazapine (CBZ), triclosan (TRI), ibuprofen (IBU), sulfadiazine (DIA), sulfamethoxazole (SMX) and sulfamethazine (SMZ) from pH 3 to 10. The membranes were characterized by physicochemical properties including hydrophobicity, surface morphology and PPCPs adsorption with or without the presence of silica fouling to validate the rejection mechanisms of PPCPs. The fouling mechanisms were investigated using the modified Hermia model. It was found that all membranes with silica fouling showed more severe permeate flux decline at low pHs (3 and 5) than at high pHs (8 and 10) by the decomposition of nonionized silica particles to form a dense gel layer on membrane surfaces, which was hard to be removed by backwash. Silica fouling rendered the membrane surface considerably more hydrophilic, and only IBU, TRI and SMZ were adsorbed on membranes. Silica fouling on tight membranes (NF90 and XLE) can promote rejection of most PPCPs because the dense fouling layer could supply membrane with synergistic steric hindrance to reduce the transportation of PPCPs across membrane surface, implying that size exclusion is the dominating mechanism. While for loose NF270, electrostatic repulsion dominates by enhanced rejection of PPCPs as pH increased. Although fouling layer could provide extra steric hindrance for NF270, its effect was overwhelmed by the accompanied cake-enhanced concentration polarization phenomenon (CEOP). CEOP impeded back diffusion of PPCPs into the feed solution, trapped and accumulated PPCPs on membrane surface so as to increase their diffusion across membrane. At all pH levels, intermediate blocking and gel layer formation was the major fouling mechanism for tight and loose membrane, respectively.

  15. Oilfield water treatment by electrocoagulation-reverse osmosis for agricultural use: effects on germination and early growth characteristics of sunflower.

    Science.gov (United States)

    de Souza, Paulo S A; Cerqueira, Alexandre A; Rigo, Michelle M; de Paiva, Julieta L; Couto, Rafael S P; Merçon, Fábio; Perez, Daniel V; Marques, Monica R C

    2016-08-22

    This study aims to evaluate the effects of oilfield water (OW), treated by a hybrid process of electrocoagulation and reverse osmosis (EC-RO), on seed germination and early growth characteristics of sunflower (Heliantus annus L.). In the EC step, tests were conducted with 28.6 A m(-2) current density and 4 min. reaction time. In the RO step, the system was operated with 1 L min(-1) constant flow and 2 MPa, 2.5 MPa and 3 MPa feed pressures. In all feed pressures, RO polymeric membranes achieved very high removals of chemical oxygen demand (up to 89%) and oils and greases (100%) from EC-treated effluent. In best feed pressure (2.5 MPa), turbidity, total dissolved salts, electrical conductivity, salinity, toxic ions and sodium adsorption ratio values attained internationally recognized standards for irrigation water. Using EC-RO (feed pressure:2.5 MPa) treated OW, germinated sunflower seeds percentage (86 ± 6%), speed of germination (30 ± 2) and biomass production (49 ± 5 mg) were statistically similar to control (distilled water) results. Vigor index average values obtained using OW treated by EC-RO (3871)were higher than that obtained by OW water treated by EC (3300). The results of this study indicate that EC-RO seems to be a promising alternative for treatment of OW aiming sunflower crops irrigation, since the use of this treated effluent did not affect adversely seed germination and seedling development, and improved seedling vigor. Furthermore, OW treatment by EC-RO reduces sodium levels into acceptable standards values avoiding soil degradation.

  16. Disinfection byproduct formation in reverse-osmosis concentrated and lyophilized natural organic matter from a drinking water source.

    Science.gov (United States)

    Pressman, Jonathan G; McCurry, Daniel L; Parvez, Shahid; Rice, Glenn E; Teuschler, Linda K; Miltner, Richard J; Speth, Thomas F

    2012-10-15

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking water research has been limited because the selected NOM sources are atypical of most drinking water sources. The purpose of this research was to demonstrate that reconstituted NOM from a lyophilized reverse-osmosis (RO) concentrate of a typical drinking water source closely represents DBP formation in the original NOM. A preliminary experiment assessed DBP formation kinetics and yields in concentrated NOM, which demonstrated that chlorine decays faster in concentrate, in some cases leading to altered DBP speciation. Potential changes in NOM reactivity caused by lyophilization were evaluated by chlorination of lyophilized and reconstituted NOM, its parent RO concentrate, and the source water. Bromide lost during RO concentration was replaced by adding potassium bromide prior to chlorination. Although total measured DBP formation tended to decrease slightly and unidentified halogenated organic formation tended to increase slightly as a result of RO concentration, the changes associated with lyophilization were minor. In lyophilized NOM reconstituted back to source water TOC levels and then chlorinated, the concentrations of 19 of 21 measured DBPs, constituting 96% of the total identified DBP mass, were statistically indistinguishable from those in the chlorinated source water. Furthermore, the concentrations of 16 of 21 DBPs in lyophilized NOM reconstituted back to the RO concentrate TOC levels, constituting 86% DBP mass, were statistically indistinguishable from those in the RO concentrate. This study suggests that lyophilization can be used to preserve concentrated NOM without substantially altering the precursors to DBP formation.

  17. Flow cytometric assessment of microbial abundance in the near-field area of seawater reverse osmosis concentrate discharge

    KAUST Repository

    Van Der Merwe, Riaan

    2014-06-01

    The discharge of concentrate and other process waters from seawater reverse osmosis (SWRO) plant operations into the marine environment may adversely affect water quality in the near-field area surrounding the outfall. The main concerns are the increase in salt concentration in receiving waters, which results in a density increase and potential water stratification near the outfall, and possible increases in turbidity, e.g., due to the discharge of filter backwash waters. Changes in ambient water quality may affect microbial abundance in the area, for example by hindering the photosynthesis process or disrupting biogenesis. It is widely accepted that marine biodiversity is lower in more extreme conditions, such as high salinity environments. As aquatic microbial communities respond very rapidly to changes in their environment, they can be used as indicators for monitoring ambient water quality. The objective of this study was to assess possible changes in microbial abundance as a result of concentrate discharge into the near-field area (<. 25. m) surrounding the outfall of the King Abdullah University of Science and Technology (KAUST) SWRO plant. Flow cytometric (FCM) analysis was conducted in order to rapidly determine microbial abundance on a single-cell level in 107 samples, taken by diving, from the discharge area, the intake area and two control sites. FCM analysis combined the measurement of distinct scatter of cells and particles, autofluorescence of cyanobacteria and algae, and fluorescence after staining of nucleic acids with SYBR® Green for a total bacterial count. The results indicate that changes in microbial abundance in the near-field area of the KAUST SWRO outfall are minor and appear to be the result of a dilution effect rather than a direct impact of the concentrate discharge. © 2014 Elsevier B.V.

  18. [Formation and Variation of Brominated Disinfection By-products in A Combined Ultrafiltration and Reverse Osmosis Process for Seawater Desalination].

    Science.gov (United States)

    Yang, Zhe; Sun, Ying-xue; Shi, Na; Hu, Hong-ying

    2015-10-01

    The characteristics of dissolved organic matter (DOM) and brominated disinfection by-products ( Br-DBPs ) during a seawater desalination ultrafiltration (UF) combined reverse osmosis (RO) process were studied. The seawater contained high level of bromide ion (45.6-50.9 mg x L(-1)) and aromatic compounds with specific ultraviolet absorbance ( SUVA) of 3.6-6.0 L x (mg x m)(-1). The tryptophan-like aromatic protein, fulvic acid-like and soluble microbial by-product-like were the main fluorescent DOM in the seawater. After pre-chlorination of the seawater, the concentrations of DBPs was significantly increased in the influent of UF, which was dominantly the Br-DBPs. Bromoform (CHBr3) accounted for 70.48% - 91.50% of total trihalomethanes (THMs), dibromoacetic acid (Br2CHCO2H) occupied 81.14% - 100% of total haloacetic acids (HAAs) and dibromoacetonitrile (C2HBr2N) occupied 83.77% - 87.45% of total haloacetonitriles ( HANs). The removal efficiency of THMs, HAAs and HANs by the UF membrane was 36.63% - 40.39%, 73.83% - 95.38% and 100%, respectively. The RO membrane could completely remove the HAAs, while a little of the THMs was penetrated. The antiestrogenic activity in the seawater was 0.35 - 0.44 mg x L(-1), which was increased 32% - 69% after the pre-chlorination. The DBPs and other bio-toxic organics which formed during the UF-RO process were finally concentrated in the UF concentrate and RO concentrate.

  19. Factors affecting fluoride and natural organic matter (NOM) removal from natural waters in Tanzania by nanofiltration/reverse osmosis.

    Science.gov (United States)

    Shen, Junjie; Schäfer, Andrea I

    2015-09-15

    This study examined the feasibility of nanofiltration (NF) and reverse osmosis (RO) in treating challenging natural tropical waters containing high fluoride and natural organic matter (NOM). A total of 166 water samples were collected from 120 sources within northern Tanzania over a period of 16 months. Chemical analysis showed that 81% of the samples have fluoride levels exceeding the WHO drinking guideline of 1.5mg/L. The highest fluoride levels were detected in waters characterized by high ionic strength, high inorganic carbon and on some occasions high total organic carbon (TOC) concentrations. Bench-scale experiments with 22 representative waters (selected based on fluoride concentration, salinity, origin and in some instances organic matter) and 6 NF/RO membranes revealed that ionic strength and recovery affected fluoride retention and permeate flux. This is predominantly due to osmotic pressure and hence the variation of diffusion/convection contributes to fluoride transport. Different membranes had distinct fluoride removal capacities, showing different raw water concentration treatability limits regarding the WHO guideline compliance. BW30, BW30-LE and NF90 membranes had a feed concentration limit of 30-40 mg/L at 50% recovery. NOM retention was independent of water matrices but is governed predominantly by size exclusion. NOM was observed to have a positive impact on fluoride removal. Several mechanisms could contribute but further studies are required before a conclusion could be drawn. In summary, NF/RO membranes were proved to remove both fluoride and NOM reliably even from the most challenging Tanzanian waters, increasing the available drinking water sources.

  20. Effectiveness of household reverse-osmosis systems in a Western U.S. region with high arsenic in groundwater

    Science.gov (United States)

    Walker, M.; Seiler, R.L.; Meinert, M.

    2008-01-01

    It is well known to the public in Lahontan Valley in rural Nevada, USA, that local aquifers produce water with varied, but sometimes very high concentrations of arsenic (> 4??ppm). As a result, many residents of the area have installed household reverse-osmosis (RO) systems to produce drinking water. We examined performance of RO systems and factors associated with arsenic removal efficiency in 59 households in Lahontan Valley. The sampling results indicated that RO systems removed an average of 80.2% of arsenic from well water. In 18 of the 59 households, arsenic concentrations exceeded 10??ppb in treated water, with a maximum in treated water of 180??ppb. In 3 of the 59 households, RO treatment had little effect on specific conductance, indicating that the RO system was not working properly. Two main factors lead to arsenic levels in treated water exceeding drinking-water standards in the study area. First, arsenic concentrations were high enough in some Lahontan Valley wells that arsenic levels exceeded 10??ppb even though RO treatment removed more than 95% of the arsenic. Second, trivalent As+ 3 was the dominant arsenic species in approximately 15% of the wells, which significantly reduced treatment efficiency. Measurements of specific conductance indicated that efficiency in reducing arsenic levels did not always correlate with reductions in total dissolved solids. As a consequence, improvements in taste of the water or simple measurements of specific conductance made by technicians to test RO systems can mislead the public into assuming the water meets safety standards. Actual measurements of treated water are necessary to assure that household RO systems are reducing arsenic concentrations to safe levels, particularly in areas where groundwater has high arsenic concentrations or where As+ 3 is the dominant species. ?? 2007 Elsevier B.V. All rights reserved.

  1. Electrochemical treatment of reverse osmosis concentrate on boron-doped electrodes in undivided and divided cell configurations

    Energy Technology Data Exchange (ETDEWEB)

    Bagastyo, Arseto Y. [Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072 (Australia); Department of Environmental Engineering, Institut Teknologi Sepuluh Nopember, Surabaya 60111 (Indonesia); Batstone, Damien J. [Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072 (Australia); Kristiana, Ina [Curtin Water Quality Research Centre, Resources and Chemistry Precinct, Department of Chemistry, Curtin University, Bentley, Perth, WA 6102 (Australia); Escher, Beate I. [National Research Centre for Environmental Toxicology (Entox), The University of Queensland, Brisbane, QLD 4108 (Australia); Joll, Cynthia [Curtin Water Quality Research Centre, Resources and Chemistry Precinct, Department of Chemistry, Curtin University, Bentley, Perth, WA 6102 (Australia); Radjenovic, Jelena, E-mail: j.radjenovic@uq.edu.au [Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072 (Australia)

    2014-08-30

    Highlights: • 100% of COD and ∼70% of DOC was removed in both cell configurations. • ∼21.7 mg L{sup −1} of AOCl and ∼2.3 mg L{sup −1} of AOBr was formed regardless of the membrane use. • The TEQ was far lower than expected given the high AOCl concentrations. • The undivided cell consumed lower energy compared to the divided cell. - Abstract: An undivided electrolytic cell may offer lower electrochlorination through reduction of chlorine/hypochlorite at the cathode. This study investigated the performance of electrooxidation of reverse osmosis concentrate using boron-doped diamond electrodes in membrane-divided and undivided cells. In both cell configurations, similar extents of chemical oxygen demand and dissolved organic carbon removal were obtained. Continuous formation of chlorinated organic compounds was observed regardless of the membrane presence. However, halogenation of the organic matter did not result in a corresponding increase in toxicity (Vibrio fischeri bioassay performed on extracted samples), with toxicity decreasing slightly until 10 Ah L{sup −1}, and generally remaining near the initial baseline-toxicity equivalent concentration (TEQ) of the raw concentrate (i.e., ∼2 mg L{sup −1}). The exception was a high range toxicity measure in the undivided cell (i.e., TEQ = 11 mg L{sup −1} at 2.4 Ah L{sup −1}), which rapidly decreased to 4 mg L{sup −1}. The discrepancy between the halogenated organic matter and toxicity patterns may be a consequence of volatile and/or polar halogenated by-products formed in oxidation by OH· electrogenerated at the anode. The undivided cell exhibited lower energy compared to the divided cell, 0.25 kWh gCOD{sup −1} and 0.34 kWh gCOD{sup −1}, respectively, yet it did not demonstrate any improvement regarding by-products formation.

  2. RESEARCH SPECIFIC FLUX OF SOLVENT IN THE PROCESSES OF ULTRAFILTRATION AND REVERSE OSMOSIS OF BIOLOGICAL SOLUTIONS SEPARATION IN BIOCHEMICAL INDUSTRY

    Directory of Open Access Journals (Sweden)

    S. I. Lazarev

    2015-01-01

    Full Text Available This work is devoted to the study of specific solvent stream in baro membrane separation processes in the biochemical industry. The main indicators, which characterize baromembranes technology, are productivity and quality division. Performance of baromembrane separation is estimated by the specific output or specific solvent stream, which is equal to the permeate flow per unit working area of the membrane per unit of time, and also determines the speed of the process of baromembrane division. This parameter depends on the material of the membrane, the nature of the solutes and their concentrations in the solution, the operating pressure, temperature and hydrodynamic processes. The article analyzed the specific solvent flow, which mathematically described by the equation based on Darcy's Law. This law establishes proportional dependence on the driving force of the process, the concentration and type of membrane. For the research was used following technique. The initial stage was to preliminary cleaning of membranes from impurities, checking the integrity of individual units, launching in work mode for a time period of 18 hours. Then there was a preliminary experience for the establishment of a permanent performance with a factor of retention membranes. After that was done a series of basic experiments, the results of which were used for calculate of specific solvent stream. As a result of investigations made certain conclusions. Specific solvent stream decreases with increasing concentration. In ultrafiltration membranes the specific solvent stream is higher than in reverse osmosis membranes. This phenomenon depends on the type of membrane. When the pressure increases the flow of the solvent and performance of baromembrane separation of solutions increases too. Specific solvent stream are influenced by concentrating polarization, gelation and sedimentation, which are formed as a result of increasing pressure and adsorption on the membrane

  3. 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.

  4. Enzymatic cleaning of biofouled thin-film composite reverse osmosis (RO) membrane operated in a biofilm membrane reactor.

    Science.gov (United States)

    Khan, Mohiuddin; Danielsen, Steffen; Johansen, Katja; Lorenz, Lindsey; Nelson, Sara; Camper, Anne

    2014-02-01

    Application of environmentally friendly enzymes to remove thin-film composite (TFC) reverse osmosis (RO) membrane biofoulants without changing the physico-chemical properties of the RO surface is a challenging and new concept. Eight enzymes from Novozyme A/S were tested using a commercially available biofouling-resistant TFC polyamide RO membrane (BW30, FilmTech Corporation, Dow Chemical Co.) without filtration in a rotating disk reactor system operated for 58 days. At the end of the operation, the accumulated biofoulants on the TFC RO surfaces were treated with the three best enzymes, Subtilisin protease and lipase; dextranase; and polygalacturonase (PG) based enzymes, at neutral pH (~7) and doses of 50, 100, and 150 ppm. Contact times were 18 and 36 h. Live/dead staining, epifluorescence microscopy measurements, and 5 μm thick cryo-sections of enzyme and physically treated biofouled membranes revealed that Subtilisin protease- and lipase-based enzymes at 100 ppm and 18 h contact time were optimal for removing most of the cells and proteins from the RO surface. Culturable cells inside the biofilm declined by more than five logs even at the lower dose (50 ppm) and shorter incubation period (18 h). Subtilisin protease- and lipase-based enzyme cleaning at 100 ppm and for 18 h contact time restored the hydrophobicity of the TFC RO surface to its virgin condition while physical cleaning alone resulted in a 50° increase in hydrophobicity. Moreover, at this optimum working condition, the Subtilisin protease- and lipase-based enzyme treatment of biofouled RO surface also restored the surface roughness measured with atomic force microscopy and the mass percentage of the chemical compositions on the TFC surface estimated with X-ray photoelectron spectroscopy to its virgin condition. This novel study will encourage the further development and application of enzymes to remove biofoulants on the RO surface without changing its surface properties.

  5. Exergy analysis of micro-organic Rankine power cycles for a small scale solar driven reverse osmosis desalination system

    Energy Technology Data Exchange (ETDEWEB)

    Tchanche, B.F.; Lambrinos, Gr.; Frangoudakis, A.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-04-15

    Exergy analysis of micro-organic Rankine heat engines is performed to identify the most suitable engine for driving a small scale reverse osmosis desalination system. Three modified engines derived from simple Rankine engine using regeneration (incorporation of regenerator or feedliquid heaters) are analyzed through a novel approach, called exergy-topological method based on the combination of exergy flow graphs, exergy loss graphs, and thermoeconomic graphs. For the investigations, three working fluids are considered: R134a, R245fa and R600. The incorporated devices produce different results with different fluids. Exergy destruction throughout the systems operating with R134a was quantified and illustrated using exergy diagrams. The sites with greater exergy destruction include turbine, evaporator and feedliquid heaters. The most critical components include evaporator, turbine and mixing units. A regenerative heat exchanger has positive effects only when the engine operates with dry fluids; feedliquid heaters improve the degree of thermodynamic perfection of the system but lead to loss in exergetic efficiency. Although, different modifications produce better energy conversion and less exergy destroyed, the improvements are not significant enough and subsequent modifications of the simple Rankine engine cannot be considered as economically profitable for heat source temperature below 100 C. As illustration, a regenerator increases the system's energy efficiency by 7%, the degree of thermodynamic perfection by 3.5% while the exergetic efficiency is unchanged in comparison with the simple Rankine cycle, with R600 as working fluid. The impacts of heat source temperature and pinch point temperature difference on engine's performance are also examined. Finally, results demonstrate that energy analysis combined with the mathematical graph theory is a powerful tool in performance assessments of Rankine based power systems and permits meaningful comparison of

  6. Evaluating the efficiency of different microfiltration and ultrafiltration membranes used as pretreatment for Red Sea water reverse osmosis desalination

    KAUST Repository

    Almashharawi, Samir

    2013-01-01

    Conventional processes are widely used as pretreatment for reverse osmosis (RO) desalination technology since its development. However, these processes require a large footprint and have some limitation issues such as difficulty to maintain a consistent silt density index, coagulation control at low total suspended solids, and management of higher waste sludge. Recently, there has been a rapid growth in the use of low-pressure membranes as pretreatment for RO systems replacing the conventional processes. However, despite the numerous advantages of using this integrated membrane system mainly providing good and stable water quality to RO membranes, many issues have to be addressed. The primary limitation is membrane fouling which reduces the permeate flux; therefore, higher pumping intensity is required to maintain a consistent volume of product. This paper aims to optimize the permeation flux and cleaning frequency by providing high permeate quality. Different low-pressure polyethersulfone membranes with different pore sizes ranging from 0.1 lm to 50 kDa were tested. Eight different filtration configurations have been applied including the variation of coagulant doses aiming to control membrane fouling. Results showed that all the configurations with/without coagulation, provided permeate with excellent water quality which improves the stability of RO performance. However, more stable fluxes with less-energy consumption were achieved by using the 0.1 lm and 100 kDa membranes with 1 mg/L FeCl3 coagulation. The use of UF membranes, having tight pores, without coagulation also proved to be an excellent option for Red Sea water RO pretreatment. © 2013 Desalination Publications.

  7. Utilization of reverse osmosis (RO) for reuse of MBR-treated wastewater in irrigation-preliminary tests and quality analysis of product water.

    Science.gov (United States)

    Bunani, Samuel; Yörükoğlu, Eren; Sert, Gökhan; Kabay, Nalan; Yüksel, Ümran; Yüksel, Mithat; Egemen, Özdemir; Pek, Taylan Özgür

    2015-02-19

    Membrane bioreactor (MBR) effluent collected from a wastewater treatment plant installed at an industrial zone was used for reverse osmosis (RO) membrane tests in the laboratory. For this, two different GE Osmonics RO membranes (AK-BWRO and AD-SWRO) were employed. The results showed that AK-brackish water reverse osmosis (AK-BWRO) and AD-seawater reverse osmosis (AD-SWRO) membranes have almost similar rejection performances regarding analyzed parameters such as conductivity, salinity, color, chemical oxygen demand (COD), and total organic carbon (TOC). On the other hand, these membranes behaved quite differently considering their permeate water flux at the same applied pressure of 10 bar. AD-SWRO membrane was also tested at 20 bar. The results revealed that AD-SWRO membrane had almost the same rejections either at 10 or at 20 bar of applied pressure. Compared with irrigation water standards, AK-BWRO and AD-SWRO gave an effluent with low salinity value and sodium adsorption ratio (SAR) which makes it unsuitable for irrigation due to the infiltration problems risi0ng from unbalanced values of salinity and SAR. Combination of MBR effluent and RO effluent at respective proportions of 0.3:0.7 and 0.4:0.6 for AK-BWRO and AD-SWRO, respectively, are the optimum mixing ratios to overcome the infiltration hazard problem. Choice of less-sensitive crops to chloride and sodium ions is another strategy to overcome all hazards which may arise from above suggested mixing proportions.

  8. Fungal treatment for the removal of endocrine disrupting compounds from reverse osmosis concentrate: Identification and monitoring of transformation products of benzotriazoles.

    Science.gov (United States)

    Llorca, Marta; Badia-Fabregat, Marina; Rodríguez-Mozaz, Sara; Caminal, Glòria; Vicent, Teresa; Barceló, Damià

    2017-10-01

    The removal of 27 endocrine-disrupting compounds and related compounds (suspect effect) from a reverse osmosis concentrate using an alternative decontamination method based on a fungal treatment involving Trametes versicolor was assessed. In addition to chemical analysis, the toxicity of the treated water during the treatment was monitored using a bioluminescence inhibition test and estrogenic and anti-estrogenic tests. The compounds 1H-benzotriazole (BTZ) and two tolyltriazoles (TTZs), 4-methyl-1H-benzotriazole (4-MBTZ) and 5-methyl-1H-benzotriazole (5-MBTZ), were present in the reverse osmosis concentrate at the highest concentrations (7.4 and 12.8 μg L(-1), respectively) and were partially removed by the fungal treatment under sterile conditions (58% for BTZ and 92% for TTZs) and non-sterile conditions, although to lesser extents (32% for BTZ and 50% for TTZs). Individual biotransformation studies of BTZ and the TTZs by T. versicolor in a synthetic medium and further analysis via on-line turbulent flow chromatography coupled to an HRMS-Orbitrap allowed the tentative identification of the transformation products (TPs). Six TPs were postulated for BTZ, two TPs were postulated for 4-MBTZ, and four TPs were postulated for 5-MBTZ. Most of these TPs are suggested to have been generated by conjugation with some sugars and via the methylation of the triazole group. Only TP 148 A, postulated to be derived from the biotransformation of BTZ, was observed in the effluent of the bioreactor treating the reverse osmosis concentrate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. The fate of Transparent Exopolymer Particles (TEP) in integrated membrane systems: removal through pre-treatment processes and deposition on reverse osmosis membranes.

    Science.gov (United States)

    Villacorte, Loreen O; Kennedy, Maria D; Amy, Gary L; Schippers, Jan C

    2009-12-01

    The abundance of Transparent Exopolymer Particles (TEP) in surface waters has been unnoticed for many years until recently as a potential foulant in reverse osmosis systems. Recent studies indicate that TEP may cause organic and biological fouling and may enhance particulate/colloidal fouling in reverse osmosis membranes. The presence of TEP was measured in the raw water, the pre-treatment processes and reverse osmosis (RO) systems of 6 integrated membrane installations. A spectrophotometric method was used to measure TEP in the particulate size range (>0.40microm) and was extended to measure TEP in the colloidal size range (0.05-0.40microm). Ultrafiltration pre-treatment applied in 4 plants, totally removed particulate TEP while microfiltration systems (2 plants) and coagulation/sedimentation/rapid sand filtration systems (3 plants) partially removed this fraction. None of the pre-treatment systems investigated totally removed colloidal TEP. Biopolymer analysis using LC-OCD showed consistency between colloidal TEP and polysaccharide removal by UF pre-treatment and further verified the presence of TEP in the RO feedwater. TEP deposition in the RO system was determined after measuring total TEP concentrations in the RO feed and concentrate. The TEP deposition factors and specific deposition rates indicate that TEP accumulation had occurred in all plants investigated. This observation was verified by an autopsy of RO modules from two RO plants. Further improvement and verification of the (modified) TEP method, in particular the calibration, is necessary so that it can be employed to investigate the role of TEP in the fouling of RO systems.

  10. Methane production in an anaerobic osmotic membrane bioreactor using forward osmosis: Effect of reverse salt flux

    KAUST Repository

    Li, Sheng

    2017-05-10

    This study investigated the impact of reverse salt flux (RSF) on microbe community and bio-methane production in a simulated fertilizer driven FO-AnMBR system using KCl, KNO3 and KH2PO4 as draw solutes. Results showed that KH2PO4 exhibited the lowest RSF in terms of molar concentration 19.1 mM/(m2.h), while for KCl and KNO3 it was 32.2 and 120.8 mM/(m2.h), respectively. Interestingly, bio-methane production displayed an opposite order with KH2PO4, followed by KCl and KNO3. Pyrosequencing results revealed the presence of different bacterial communities among the tested fertilizers. Bacterial community of sludge exposed to KH2PO4 was very similar to that of DI-water and KCl. However, results with KNO3 were different since the denitrifying bacteria were found to have a higher percentage than the sludge with other fertilizers. This study demonstrated that RSF has a negative effect on bio-methane production, probably by influencing the sludge bacterial community via environment modification.

  11. 反渗透浓缩法提取乳糖的工艺参数研究%Research on Processing Parameters of Lactose Concertrated by Reverse Osmosis

    Institute of Scientific and Technical Information of China (English)

    施立钦

    2011-01-01

    采用超滤膜分离乳清粉中的乳清蛋白,离子交换树脂提取唾液酸并除去乳糖溶液中的杂质,运用芳香聚酰胺卷式反渗透膜进行浓缩;通过对操作压强、工作温度、渗透通量、浓缩倍数等因素对反渗透浓缩结果的影响,确定了反渗透法浓缩提取乳糖的工艺参数为:采用芳香聚酰胺卷式反渗透膜装置,操作压力为0.5 MPa、工作温度为40℃、乳糖的单级截留率为95%左右,乳糖的成品质量指标,符合相关的国标要求。与现行的结晶工艺相比,污染少、能耗底、收率高,具有良好的开发前景。%The paper describes the use of ultrafiltration membrane separation of whey in the whey protein,ion exchange resin to extract Sialic acid and remove impurities in the lactose solution and aromatic polyamide spiral reverse osmosis membrane to concentrate whey protein.The reverse osmosis process parameters affecting the results of the reverse osmosis concentrate for the lactose were determined by operating pressure,temperature,flux,concentration ratio and other factors.The use of aromatic polyamide spiral reverse osmosis membrane unit,the operating pressure of 0.5 MPa,the operating temperature of 40 ℃,lactose retention rate of 95% single-stage about lactose product quality indicators,in line with the relevant national standard.The crystallization process compared with the existing,is less pollution,less energy consumption,higher yield with good prospects of development.

  12. Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.

    1978-02-01

    Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

  13. Pilot study on arsenic removal from groundwater using a small-scale reverse osmosis system-Towards sustainable drinking water production.

    Science.gov (United States)

    Schmidt, Stefan-André; Gukelberger, Ephraim; Hermann, Mario; Fiedler, Florian; Großmann, Benjamin; Hoinkis, Jan; Ghosh, Ashok; Chatterjee, Debashis; Bundschuh, Jochen

    2016-11-15

    Arsenic contamination of groundwater is posing a serious challenge to drinking water supplies on a global scale. In India and Bangladesh, arsenic has caused the most serious public health issue in the world for nearly two decades. The aim of this work was to study an arsenic removal system based on reverse osmosis at pilot scale treating two different water sources from two different locations in the State of Bihar, India. For this purpose two villages, Bind Toli and Ramnagar in the Patna District were selected, both located very close to the river Ganga. The trials were conducted with aerated and non-aerated groundwater. It is the first time that the arsenic removal efficiency for aerated and non-aerated groundwater by reverse osmosis technology in combination with an energy-saving recovery system have been studied. As the principle of reverse osmosis requires a relatively high pressure, its energy demand is naturally high. By using an energy recovery system, this demand can be lowered, leading to an energy demand per liter permeate of 3-4Wh/L only. Due to high iron levels in the groundwater and as a consequence the precipitation of ferric (hydr)oxides, it was necessary to develop a granular media filter for the trials under aeration in order to protect the membrane from clogging. Two different materials, first locally available sand, and second commercially available anthracite were tested in the granular media filter. For the trials with aerated groundwater, total arsenic removal efficiency at both locations was around 99% and the arsenic concentration in permeate was in compliance with the WHO and National Indian Standard of 10μg/L. However, trials under anoxic conditions with non-aerated groundwater could not comply with this standard. Additionally a possible safe discharge of the reverse osmosis concentrate into an abandoned well was studied. It was observed that re-injection of reject water underground may offer a safe disposal option. However, long

  14. Accumulation of GdCl3 in the feed of a reverse osmosis system during desalination as determined by neutron absorption

    Science.gov (United States)

    Schwahn, D.; Pipich, V.; Kasher, R.; Oren, Y.

    2016-09-01

    This article deals with the application of in-situ small-angle neutron scattering to investigate wastewater desalination by reverse osmosis. In a first series of experiments we take advantage of the strong neutron absorption of gadolinium (Gd) and use 0.50 g/L GdCl3 in the feed as an indicator for concentration polarization and scaling at the membrane surface. The continuous decline of scattering during the process of desalination indicates an increase of GdCl3 salt concentration which after 15 hours has achieved nearly 100% enhancement with respect to its initial concentration.

  15. Dispersive Tidal Plume Modeling of Brine Discharge from Reverse Osmosis (RO) Desalination System, Coral Bay, St. John, USVI using Finite Segment Steady-state Response Matrix (SSRM)

    Science.gov (United States)

    Yoon, J.; Shahvari, A.

    2011-12-01

    This characterization and modeling study of dispersive tidal plume of brine discharge from reverse osmosis (RO) desalination system is a part of the Environmental Assessment (EA) for a new reverse osmosis system in the Coral Bay, St. John, USVI (US Virgin Island). Main foci are on developing the tidal longitudinal (perpendicular to the shoreline) and lateral (parallel to the shoreline) dispersion coefficients and subsequently characterize dispersion and mixing characterization of the negatively buoyant brine discharge plume from the proposed reverse osmosis plant to evaluate the level of salinity variations in the nearshore mixing plume in regard to existing coral reef ecosystem. An in situ dye study was conducted by a marine biologist for this purpose to estimate brine discharge plume dispersion coefficients under oscillatory tidal transport and fate flux for current and proposed plant configuration. Additional tidal and surface runoff hydrologic data, bathymetric data and brine discharge characteristics in the vicinity of the brine discharge location are reflected in this study. With estimated dispersion coefficients, eighteen brine discharge scenarios were evaluated to model anticipated dispersive characteristics under varying operational conditions and ambient tidal current conditions for average measured salinity of 33.27 PSU in loco as well as a standard 35 PSU for typical nearshore water salinity variations. Modeling results indicated that the dispersive tidal plume of design brine discharge from reverse osmosis (RO) desalination system at a discharge of 150,000 gpd would raise salinity no higher than 0.0123 PSU in receiving nearshore estuarine water (Maximum concentration at the segment 3 = 33.2822 PSU at Δt = 12 hrs and 24 hrs in diurnal tidal cycle under when the brine discharge with Base+25% concentration, 81.25 PSU at brine discharge rate of 0.0066 m3/sec, and with a minimum direct overland flow efflux at 0.003 m3/sec - this is a "worst-case" operating

  16. Advantages of the appropriate selection of reverse osmosis membranes in desalination plants with open intake; Ventajs de una adecuada seleccion de membranas de osmosis inversa en plants desaladoras con captacion superficial abierta

    Energy Technology Data Exchange (ETDEWEB)

    Munoz Elguera, A.; Nishida, M.

    2001-07-01

    It is hoped to make it sufficiently clear with this article that it is of fundamental importance that the reverse osmosis membranes and the conditions under which they will operate be appropriately selected. It is obvious that this choice must be made primarily in function of the quality of the water that will be processed in the water treatment plant ( for which reason it is of vital importance that a detailed study and careful characterisation of this water be carried out previously). This article report the highly encouraging results achieved with Cellulose Tri-acetate membranes in a singular Hollow fibre configuration, known commercially as Hollosep HM 10255FI (of Japanese manufacture), which were evaluated in parallel with LP3 potabilisation membranes that process sea water collected using an open intake system with high levels of microbiological pollution. (Author) 7 refs.

  17. Energy consumption in reverse osmosis seawater desalination: current situation and perspectives; El consumo de energia en la dealacion de agua de mar por osmosis iversa: situacion actual y perspectivas

    Energy Technology Data Exchange (ETDEWEB)

    Estevan, A.; Garcia Sanchez -Colomer, M.

    2007-07-01

    This article shows a calculations of the specific consumption generated during the processes of reverse osmosis in a seawater desalination plant, by two different systems of energy recovery: Pelton turbines and isobaric chambers. ideal physical consumption and minimal industrial consumption are defined, and compared with the real consumptions registered in four seawater desalination plants in Spain. finally, the margins to reduce the energy consumptions in this process and the current tendencies in framework of technological progress are examined. With a work pressure of 70 atm and a conversion index of 45%, the ideal physical consumption reaches 1,97 kWh/m{sup 3}. In a context of the best available technology, with ideal assembly and operation, the minimal industrial consumption applying Pelton turbines is 2,74 kWh/m{sup 3}, whereas with isobaric chambers goes down up to 2,51 kWh/m{sup 3}. Te ideal consumptions calculated for plants with Pelton turbines in real assembly and operation change between 2,9 and 3,1 kWh/m{sup 3}. This analysis concludes that the available margins to reduce the energy consumptions are already quite limited, because the principal Spanish desalination plants rise above optimal consumptions calculated in the reverse osmosis phase in a margin changing between a 9% and 14%. In the short term the possibility of the widespread use of isobaric chambers instead of Pelton turbines is considered, together with a small reduction of the work pressure, and some improving in the architecture of the desalination plants. (Author)

  18. Spiral Wound Reverse Osmosis Membranes for the Recovery of Phenol Compounds-Experimental and Parameter Estimation Studies

    Directory of Open Access Journals (Sweden)

    G. Srinivasan

    2010-01-01

    Full Text Available Problem statement: Reverse osmosis is increasingly used as a separation technique in chemical and environmental engineering for the removal of organics and organic pollutants present in waste water. The removal of an organic compound, namely phenol, using a polyamide membrane was investigated in this study. Waste water containing phenol present a serious environmental problem and increasing attention is being given for its removal using RO membranes. Objective of this study is to (i generate experimental data related to the removal of phenol using a spiral wound polyamide membrane (ii analyze the performance of the membrane using solution-diffusion model and validate the model with the experimental data. Approach: Experiments were conducted on a laboratory scale spiral wound polyamide RO module. The permeate concentrations and rejection coefficient values were measured for various feed inlet pressures and feed concentrations. The total feed flow rate, 3.33×10-4 m3 sec-1 (20 LPM was not varied. The transport of solvent and solute through the membranes were analyzed using solution-diffusion model taking concentration polarization into account. Results: By varying inlet pressures from 4-14 kgf cm-2 and feed concentrations of phenol from 200-1100 ppm, the rejection coefficients of the membrane were measured and found to vary from 64-91%. The solvent and solute transport parameters were determined by a graphical procedure using the experimental data and its values were 5.9×10-7 (m atm-1 and 6.54×10-7 (m sec-1 respectively. Conclusion: The model and the estimated parameter values were validated with the experimental data. The model was able to predict the rejection within 10% error. In view of the fact that not much information is available on the usage of spiral wound polyamide RO membrane modules for the removal of phenolic compounds, it may be concluded that the experimental results reported in this study is very significant in the scale up and

  19. Performance evaluation of reverse osmosis desalination plants for rural water supply in a developing country--a case study.

    Science.gov (United States)

    Kelkar, P S; Joshi, V A; Ansari, M H; Manivel, U

    2003-12-01

    Performance evaluation of two reverse osmosis (RO) desalination plants (DSP) at villages: Melasirupodhu (30 m3 day(-1)) and Sikkal (50 m3 day(-1)) in Ramanathpuram district, Tamil Nadu (India) were studied so as to bring out the state-of-art of their operation and maintenance (O&M). Detailed information on plant design and engineering, water quality, plant personnel, and cost of O&M was collected for a period of three years after commissioning of the two plants. Feed water was brackish, the TDS varied in the range of 6500-8500 mg L(-1) at Melasirupodhu and 5300-7100 mg L(-1) at Sikkal villages. The product water quality was observed to be gradually deteriorating as the salt rejection by the membranes decreased with time. The salt rejection was 97-99% at the time of commissioning of the plants, and came down to 89-90% at the end of 3 years of operation. Product water TDS soon after installation of the plants was excellent and within desirable limits of BIS. After three years of operation, few parameters exceeded the desirable limits, however, they were found to be within permissible limits of BIS. The analyses of the data showed that both plants were operated only at 30-36% of the design capacity. Plant shut-down due to inadequate and erratic power supply, and plant break-down and inherent delay in repairs due to lack of adequate infrastructure were found to be the major causes for the low utilization of the plants. Consequently the recurring cost of product water production enhanced to Rs. 25.0/m3 at Melasirupodhu and Rs. 17.5 m(-3) at Sikkal, as against the estimated cost of Rs. 15.0/m3 and Rs. 11.0/m3, respectively, as per the design. Over the years, the energy consumption for the product water output increased reflecting higher operational pressures needed with the aging of the membranes.

  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. A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates

    Science.gov (United States)

    Maurice, P.A.; Pullin, M.J.; Cabaniss, S.E.; Zhou, Q.; Namjesnik-Dejanovic, K.; Aiken, G.R.

    2002-01-01

    This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (??), absorbance at 280nm normalized to moles C (??280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO>XAD-8>RFW>XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO

  2. Feasibility of Gallery Intake Systems for Seawater Reverse Osmosis Facilities along the Northern Red Sea Coast of Saudi Arabia

    KAUST Repository

    Dehwah, Abdullah

    2012-03-01

    The Kingdom of Saudi Arabia is dependent on desalination of seawater to provide new water supplies for the future. Desalination is expensive and it is very important to reduce the cost and lower the energy consumption. Most seawater reverse osmosis facilities use open-ocean intakes, which require extensive pre-treatment processes to remove particulate and biological materials that cause operating problems. An alternative intake is the subsurface system which utilizes the concept of riverbank filtration using wells or galleries and provides natural filtration to improve the quality of feedwater before it enters the desalination plant. This reduces operating cost and lowers energy consumption. Research was focused on evaluating gallery-type intakes (beach and seabed galleries) that could be used along the Northern Red Sea shoreline to provide a better quality feedwater for desalination. The geological characteristics of the visited sites were favorable for the development of seabed filter systems (offshore), but not for beach gallery intakes. The low wave energy along the shoreline and the presence of mud or rocky coasts made beach galleries infeasible. One of the potentially favorable sites for a seabed filter was located in the nearshore area at King Abdullah Economic City (KAEC). This site has a predominantly sandy offshore bottom with shallow water depths, and a low tide range. In addition, the bottom is always covered with water and contains soft limestone unit below the sand mantle that could be easy excavated to facilitate the construction of a seabed filter. About 50 sediment samples were collected from the site and laboratory measurements were performed on them. Grain size distribution, porosity and hydraulic conductivity measurements were performed on the sediment samples. In addition, six statistical methods were used to estimate the hydraulic conductivity values. Based on results of lab measurements, field observations, tide ranges and sediment types, it

  3. THE DEVELOPMENT OF CONTROL SYSTEM OF REVERSE OSMOSIS WATER TREATMENT UNIT%反渗透水处理设备电导率控制系统的研制

    Institute of Scientific and Technical Information of China (English)

    李修仁; 秦旭达; 哈鼎文

    2001-01-01

    本文介绍了一种模糊控制器,应用于反渗透水处理设备中,可实现电导率实时自动控制,提高了反渗透水处理过程中设备工作效率和水的利用率。%This paper introduces a fuzzy controller that authors designed. It was applied to reverse osmosis water treatment unit, realizing the conductivity auto-controlled and raising the working efficiency of the equipment and the utilization ratio of water remarkably in the reverse osmosis process.

  4. Relationship between performance deterioration of a polyamide reverse osmosis membrane used in a seawater desalination plant and changes in its physicochemical properties.

    Science.gov (United States)

    Suzuki, Tasuma; Tanaka, Ryohei; Tahara, Marina; Isamu, Yuya; Niinae, Masakazu; Lin, Lin; Wang, Jingbo; Luh, Jeanne; Coronell, Orlando

    2016-09-01

    While it is known that the performance of reverse osmosis membranes is dependent on their physicochemical properties, the existing literature studying membranes used in treatment facilities generally focuses on foulant layers or performance changes due to fouling, not on the performance and physicochemical changes that occur to the membranes themselves. In this study, the performance and physicochemical properties of a polyamide reverse osmosis membrane used for three years in a seawater desalination plant were compared to those of a corresponding unused membrane. The relationship between performance changes during long-term use and changes in physicochemical properties was evaluated. The results showed that membrane performance deterioration (i.e., reduced water flux, reduced contaminant rejection, and increased fouling propensity) occurred as a result of membrane use in the desalination facility, and that the main physicochemical changes responsible for performance deterioration were reduction in PVA coating coverage and bromine uptake by polyamide. The latter was likely promoted by oxidant residual in the membrane feed water. Our findings indicate that the optimization of membrane materials and processes towards maximizing the stability of the PVA coating and ensuring complete removal of oxidants in feed waters would minimize membrane performance deterioration in water purification facilities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Occurrence of N-nitrosodimethylamine precursors in wastewater treatment plant effluent and their fate during ultrafiltration-reverse osmosis membrane treatment.

    Science.gov (United States)

    Farré, M J; Keller, J; Holling, N; Poussade, Y; Gernjak, W

    2011-01-01

    The formation of N-nitrosodimethylamine (NDMA) is of major concern among wastewater recycling utilities practicing disinfection with chloramines. The NDMA formation potential (FP) test is a simple and straightforward method to evaluate NDMA precursor concentrations in waters. In this paper we show the NDMA FP results of a range of tertiary wastewater treatment plants that are also the source for production of recycled water using an Ultrafiltration - Reverse Osmosis (UF-RO) membrane process. The results indicate that the NDMA FP of different source waters range from 350 to 1020±20 ng/L. The fate of these NDMA precursors was also studied across the different stages of two Advanced Water Treatment Plants (AWTP) producing recycled water. These results show that more than 98.5±0.5% of NDMA precursors are effectively removed by the Reverse Osmosis (RO) membranes used at the AWTPs. This drastically reduces any potential for re-formation of NDMA after the RO stage even if chloramines may be present (or added) there.

  6. Aquifer composition and the tendency toward scale-deposit formation during reverse osmosis desalination - Examples from saline ground water in New Mexico, USA

    Science.gov (United States)

    Huff, G.F.

    2006-01-01

    Desalination is expected to make a substantial contribution to water supply in the United States by 2020. Currently, reverse osmosis is one of the most cost effective and widely used desalination technologies. The tendency to form scale deposits during reverse osmosis is an important factor in determining the suitability of input waters for use in desalination. The tendency toward scale formation of samples of saline ground water from selected geologic units in New Mexico was assessed using simulated evaporation. All saline water samples showed a strong tendency to form CaCO3 scale deposits. Saline ground water samples from the Yeso Formation and the San Andres Limestone showed relatively stronger tendencies to form CaSO4 2H2O scale deposits and relatively weaker tendencies to form SiO2(a) scale deposits than saline ground water samples from the Rio Grande alluvium. Tendencies toward scale formation in saline ground water samples from the Dockum Group were highly variable. The tendencies toward scale formation of saline waters from the Yeso Formation, San Andres Limestone, and Rio Grande alluvium appear to correlate with the mineralogical composition of the geologic units, suggesting that scale-forming tendencies are governed by aquifer composition and water-rock interaction. ?? 2006 Elsevier B.V. All rights reserved.

  7. 反渗透膜运行的问题分析%Analysis of Problems in Operation of Reverse Osmosis Membranes

    Institute of Scientific and Technical Information of China (English)

    吕慧

    2012-01-01

    The troubles in the reverse osmosis system of waste water treatment plant of PetroChina Dushanzi Petrochemical Company are analyzed.The results of preliminary analysis indicate that the reverse osmosis(RO) membranes suffer from membrane fouling by inorganic salts and organic materials,which is resulted from off-spec water input of RO system.The membrane fouling bring numerous problems,e.g.,decrease of water production,the rise of pressure,increase of energy consumption and requirement of frequent membrane cleaning.The shortcomings of cleaning of reverse osmosis are discussed.The correction measures are proposed based upon the analysis:(1) acid addition is provided at the water inlet of reverse osmosis to reduce the pH value(6.0 ~ 7.5) and HCO3-and fouling inhibition is adopted.These will reduce Langelier saturation index and control the fouling.2.Protective cleaning measure is taken.(3) The inlet water quality is monitored and controlled.Good results have been achieved after implementation of these measures.%针对中国石油独山子石化公司乙烯厂污水深度处理装置中反渗透膜系统故障问题进行了分析,初步分析表明由于进水水质不合理,RO膜表面会发生无机盐的结垢及有机物的污堵,导致产水量降低,压差上升,能耗增加,需要频繁的膜清洗,同时指出反渗透膜清洗的不足之处,最后在现有基础上提出了整改建议,一是在反渗透进水口处增加加酸点降低反渗透进水的pH值到6.0~7.5,降低HCO3-质量浓度后再进行阻垢处理,这样才能降低朗格利尔饱和系数,有效抑制结垢;二是实施保护性清洗措施;三是前段水质预警监测措施。现场应用情况显示效果较好。

  8. 反渗透膜分离性能及其在制冷空调中的应用%Separation Performance of the Reverse Osmosis Membrane and Its Application in Air-conditioning

    Institute of Scientific and Technical Information of China (English)

    胡会涛; 杜垲; 张友超; 鄂文汲

    2014-01-01

    介绍了反渗透膜的分离机理,归纳了多种分离过程理论模型的通量公式、应用场合及其局限性,综述了操作压力、料液温度、料液浓度以及料液流速等特性参数对反渗透膜分离性能的影响,解读了反渗透膜分离技术在制冷空调中的应用研究,为反渗透膜分离技术在制冷空调行业的应用提供了参考。%The separation mechanism of reverse osmosis membrane was described. Flux formulas,applications and limitations of various theoretical separation models were summarized here. The effects that operating pressure, feed temperature, feed concentration and feed flow rate have on performance of the reverse osmosis membrane separation were analyzed systematically. Finally,the applications using re-verse osmosis membrane separation technology in refrigeration and air conditioning industry were demonstrated,which provides a reference for the applications of reverse osmosis membrane separation technology in refrigeration and air conditioning industry.

  9. TiO2纳米管修饰电极处理反渗透浓水研究%Study on Treatment of Reverse Osmosis Concentrate by TiO2 Nanotubes Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    尹协东; 陈勇; 林乔乔

    2014-01-01

    The novel TiO2 nanotubes modified electrode was obtained for electrochemical oxidation of reverse osmosis concentrate. Scanning electron microscope (SEM) and linear polarization curves were characterized for the electrode. The influences of electrolysis time, current density and pH on electrochemical oxidation of reverse osmosis concentrate were studied. The removal of different organic fraction of reverse osmosis concentrate by electrode was also discussed. The results showed that the TiO2 nanotubes modified electrode had high electrochemical performance for the treatment of reverse osmosis concentrate.%研制了新型的TiO2纳米管修饰电极,应用于反渗透膜浓水的电化学氧化处理;利用扫描电镜和线性极化曲线对电极进行了表征;考察了电解时间、电流密度和pH值因素对电化学氧化处理反渗透膜浓水的影响;并分析了电极对反渗透浓水中各有机物组分的去除效果。实验结果表明TiO2纳米管修饰电极对反渗透浓水具有较高的电催化性能。

  10. 反渗透差动式能量回收装置的试验研究%Study on Differential-type Energy Recovery Device in Reverse Osmosis

    Institute of Scientific and Technical Information of China (English)

    潘献辉; 王生辉; 杨守智

    2011-01-01

    研究开发了一种反渗透淡化用差动式能量回收装置,并对装置进行了性能测试和8×24 h连续运行试验.结果表明:该差动式能量回收装置的全部指标均符合国家海洋行业标准(HY/T 108-2008)的要求,有效能量转换效率达到94.6%以上.该装置运行平稳,满足反渗透系统使用需要,已成功应用于海水RO膜的检测.%A differential-type energy recovery device in reverse osmosis desalination was developed. After performance test and continuous running test of 8 × 24 hours, the results indicate that all performance index of the differential-type energy recovery device meet the requirements of Energy Recovery Device in Reverse Osmosis (HY/T 108 -2008). Moreover, the energy transfer efficiency is over 94.6%.This energy recovery device can be operated stably and meet the requirements of reverse osmosis desalination system, which has been already used in test of reverse osmosis membrane successfully.

  11. The Application of Reverse Osmosis Technology in QingJiang Petrochemical Demineralized Water Process%反渗透技术在清江石化除盐水工艺中的应用

    Institute of Scientific and Technical Information of China (English)

    周健; 华伦

    2012-01-01

    This paper summarizes the structure,producing area and application industry of the Dow reverse osmosis membrane membrane.The technical process,the process control parameters(recovery rate,desalination rate,in-and-out water quality) and process flow and reverse osmosis desalting operation of the reverse osmosis desalting device in Qingjiang petrochemical plant are included.The use of Dow reverse osmosis membrane element,the characteristics and the application,design principle of process,process flow,parameters,and the cleaning frequency in application are also covered.At the same time,some relevant improvement measures are proposed.%综述了陶氏反渗透膜的膜结构、产地及应用行业。阐述了清江石化反渗透脱盐装置的工艺过程、工艺控制参数(回收率、脱盐率、进出水水质)及工艺流程和反渗透脱盐装置的运行情况,包括使用的陶氏反渗透膜元件的特点及应用,设计的工艺原理、流程、参数,以及应用中存在的清洗周期短、制水比居高不下等问题及相关改进措施。

  12. Modeling the effect of charge density in the active layers of reverse osmosis and nanofiltration membranes on the rejection of arsenic(III) and potassium iodide.

    Science.gov (United States)

    Coronell, Orlando; Mi, Baoxia; Mariñas, Benito J; Cahill, David G

    2013-01-02

    We used an extended solution-diffusion model that incorporates Donnan electrostatic exclusion of ions and unhindered advection due to imperfections, and measurements of charge density in the polyamide active layers of reverse osmosis (RO) and nanofiltration (NF) membranes, to predict the rejection of a strong electrolyte (i.e., potassium iodide) and a weak acid (i.e., arsenious acid) as a function of the pH of the feed aqueous solution. Predictions of solute rejection were in agreement with experimental data indicating that (i) the extended solution-diffusion model taking into account Donnan exclusion and unhindered advection due to imperfections satisfactorily describes the effect of pH on solute rejection by RO/NF membranes and (ii) measurement of charge density in active layers provides a valuable characterization of RO/NF membranes. Our results and analysis also indicate that independent ions, and not ion pairs, dominate the permeation of salts.

  13. Pilot Study on MBBR Process to Treat Reverse Osmosis Concentrated Brine%MBBR工艺处理反渗透浓盐水中试研究

    Institute of Scientific and Technical Information of China (English)

    尹航; 杜娟; 盛培展; 祝群力; 苗利利; 余迎春

    2015-01-01

    The effect of the process of moving bed biofilm reactor (MBBR) in treatment of reverse osmosis concentrated brine in steel industry was investigated through field pilot-scale experiment. The results showed that the effect of MBBR to remove ammonia nitrogen is very obvious, with the removal above 90%. The effect of COD removal by MBBR is also good, with the removal rate above 70%. This pilot experiment provided valuable experience for future practical engineering.%通过现场中试考察了MBBR工艺处理钢铁企业反渗透浓盐水的效果。中试结果表明,MBBR对于氨氮的去除效果明显,去除率稳定在90%以上;对浓盐水中COD也有很好的去除效果,去除率达70%以上。

  14. Identification of some factors affecting pharmaceutical active compounds (PhACs) removal in real wastewater. Case study of fungal treatment of reverse osmosis concentrate.

    Science.gov (United States)

    Badia-Fabregat, Marina; Lucas, Daniel; Gros, Meritxell; Rodríguez-Mozaz, Sara; Barceló, Damià; Caminal, Glòria; Vicent, Teresa

    2015-01-01

    Many technologies are being developed for the efficient removal of micropollutants from wastewater and, among them, fungal degradation is one of the possible alternative biological treatments. In this article, some factors that might affect pharmaceutically active compounds (PhACs) removal in a fungal treatment of real wastewater were identified in batch bioreactor treating reverse osmosis concentrate (ROC) from urban wastewater treatment plant (WWTP). We found that degradation of PhACs by Trametes versicolor was enhanced by addition of external nutrients (global removal of 44%). Moreover, our results point out that high aeration might be involved in the increase in the concentration of some PhACs. In fact, conjugation and deconjugation processes (among others) affect the removal assessment of emerging contaminants when working with real concentrations in comparison to experiments with spiked samples. Moreover, factors that could affect the quantification of micropollutants at lab-scale experiments were studied.

  15. Theoretical Investigation on Internal Leakage and Its Effect on the Efficiency of Fluid Switcher-Energy Recovery Device for Reverse Osmosis Desalting Plant

    Institute of Scientific and Technical Information of China (English)

    乞炳蔚; 王越; 王照成; 张燕平; 徐世昌; 王世昌

    2013-01-01

    This work is focused on the theoretical investigation of internal leakage of a newly developed pi-lot-scale fluid switcher-energy recovery device (FS-ERD) for reverse osmosis (RO) system. For the purpose of in-creasing FS-ERD efficiency and reducing the operating cost of RO, it is required to control the internal leakage in a low level. In this work, the internal leakage rates at different leakage gaps and retentate brine pressures are investi-gated by computational fluid dynamics (CFD) method and validating experiments. It is found that the internal leak-age has a linear relationship with the retentate brine pressure and a polynomial relationship with the scale of leakage gap. The results of the present work imply that low internal leakage and high retentate brine pressure bring benefits to achieve high FS-ERD efficiency.

  16. 反渗透浓缩沼液预处理试验研究%Pretreatment of Biogas Slurry for Its Concentrating by Reverse Osmosis

    Institute of Scientific and Technical Information of China (English)

    梁康强; 朱民; 林秀军; 孙宇

    2013-01-01

    采用反渗透膜工艺浓缩沼液,针对沼液悬浮物颗粒过大浓度过高、钙镁离子超标等问题,采取预处理手段对反渗透膜片进行保护,以保证系统的产水量和运行成本达到最佳.结果表明,在自然沉淀、混凝、离心过滤和滤袋过滤四种去除悬浮物工艺中,自然沉淀和离心过滤效果最佳,其出水悬浮物粒径均在10 μm以下.通过自然沉淀时间优化,自然沉淀最佳时间为1天,既能保证出水效果,又能节省沉淀池容和投资.对于钙镁离子和硫酸根离子结垢,采用反渗透膜厂家提供配方,并智能化添加阻垢剂,长期运行结果证明,防结垢效果较好,平均碱洗周期为120 h,酸洗周期为360 h.%There are some problems in biogas slurry concentrating by reverse osmosis method, which related to the suspended solid, calcium and magnesium ions in biogas slurry, for the diameter of suspend solid is too long and the concentration is too high, and both calcium and magnesium contents were exceed the standard. Accordingly, the pretreatment process protecting the reverse osmosis membrane is put forward in this paper so as to ensure the maximum water production and least operation cost. The results showed that, among the methods of natural precipitation, coagulation, centrifugal filter and bag filter processe, the natural sedimentation and centrifugal filtration had the best effectiveness, for the particle size of suspended solids in pretreated biogas slurry was smaller than 10 μm. Through optimization, the best precipitation period was 1 day. In this way, not only the water production could be guaranteed, but also sedimentation tank volume could be smaller and investment cost could be lower. As for the calcium, magnesium and sulfate ion scaling, formula was provided by osmosis membrane manufacturers and intelligent scaling inhibitor was added. The long-term operation results showed well anti-scaling performance. The average alkali-wash cycle was 120h

  17. An integrated mechanical-enzymatic reverse osmosis treatment of dairy industry wastewater and milk protein recovery as a fat replacer: a closed loop approach

    Directory of Open Access Journals (Sweden)

    F. Sarghini

    2013-09-01

    Full Text Available The dairy industry can be classified among the most polluting of the food industries in volume in regard to its large water consumption, generating from 0.2 to 10 L of effluent per liter of processed milk. Dairy industry effluents usually include highly dissolved organic matter with varying characteristics, and a correct waste management project is required to handle. In a framework of natural water resource availability and cost increase, wastewater treatment for water reuse can lower the overall water consumption and the global effluent volume of industrial plants. Moreover, correct dismissal of dairy industry wastewater is sometimes neglected by the operators , increasing the environmental impact due to the chemical and biological characteristics of such effluents. On the other hand, in the case of whey effluents, several by-products are still present inside, such as lactose and milk proteins. Membrane technology has some advantages including a high degree of reliability in removing dissolved, colloidal and particulate matter, like the selectivity in size of pollutants to be removed and the possibility of very compact treatment plants. For example, Reverse Osmosis (RO technology has been successfully applied for the treatment of dairy wastes (1, and as a technology for concentration and fractionation of whey. In this work a membrane treatment approach using reverse osmosis technology is investigated and implemented: the permeate obtained can be reused as clean warm water for cleaning and sanitation of production plants, while concentrated milk proteins are modified by using transglutaminase enzyme obtaining a high temperature resistant fat replacer to be used in different low-fat products like for example mozzarella cheese.

  18. 反渗透膜法在污水回用上的应用%The Application of Reverse Osmosis Membrane in Wastewater Recycle

    Institute of Scientific and Technical Information of China (English)

    申庆伟

    2011-01-01

    Based on the engineering example of reverse osmosis membrane for desalination, first the salt, organics, microorganism and other electrolyte etc. In wastewater from petrochemical industry were disposed by the membrane, then the water supplied to ion exchange resin system, further removal of salts in the water by the system, quality of the water to meet standards for boiler, application of the membrane technology in industry achieved. Two kinds of chemical treatment methods for wastewater were analyzed in technical economy, the results showed that wastewater was recycled with process of reverse osmosis membrane to bring out a certain amount of economic, social and environmental benefits.%根据工程实例选用反渗透膜法进行污水脱盐处理,以降低石化污水中盐、有机物、微生物及电解质含量,反渗透装置的出水再送到离子交换系统,经过阴阳离子交换树脂进一步脱除水中的盐分,达到锅炉给水的水质标准,从而实现反渗透膜的工业应用。此外,本文还对两种化学水处理方式进行技术经济性分析,说明反渗透膜法在污水回用上具有一定的经济效益、社会效益和环境效益。

  19. Cause analysis of pressure difference swift rise of the first period membrane in reverse osmosis device%反渗透装置一段压差迅速上升的原因分析

    Institute of Scientific and Technical Information of China (English)

    高玉春

    2012-01-01

    针对大唐南京发电厂2×660MW超超临界机组化学水处理系统反渗透装置运行期间一段压差迅速上升问题进行了分析,故障原因为合有高分子助凝剂(聚丙烯酰胺)的污泥脱水分离液进入反渗透系统,造成反渗透膜严重污堵;采用了离线物理清理和在线化学清洗相结合的方法,使反渗透装置恢复了正常运行。分析结果走明:在化学水处理设置有反渗透系统的新建电厂中,合有高分子聚丙烯酰胺的污泥脱水分离液,应单独排放到工业废水池或煤冲洗水复用系统中,以免造成后续反渗透系统膜元件的严重污染。%Aiming at the problem of pressure difference swift rise of reverse osmosis device of chem' istry water treatment system in operation of 2×660 MW ultra supercritical unit in Datang Nanjing Electric Power Plant, analyzes the cause of fault, the fault reason is that sludge dewatering separated liquid containing high polymer coagulant(polyacrylamide) come into reverse osmosis system, which caused the serious blockage of the reverse osmosis membrane. By using the methods of combining off line physical clearance with on line chemical cleaning, make reverse osmosis device resuming normal operation. The analysis result shows that: the chemical water treatment unit with reverse osmosis system in new built power plant, the sludge dewatering separated liquid containing macromolecule polyacryl- amide should be discharge solely into the industrial waste water pool or coal rinsing water multiplexing system, avoid serious pollution of follow-up membrane element of reverse osmosis system.

  20. The pre-treatment of water in a reverse osmosis system. Its significant importance in the design and management of the process; Pretratamiento del agua en un sistema de osmosis inversa. Su significada importancia dentro del diseno y gestion del proceso

    Energy Technology Data Exchange (ETDEWEB)

    Pujadas, A.

    2001-07-01

    The practical application of reverse osmosis technology is really easy and facilities should function without serious problems. The real difficulty is presented by the pre-treatment and conditioning of water before entering the membrane system. The present article enumerates the series of most habitual problems presented by medium or low-saline water for its correct treatment in a reverse osmosis system, also enumerating the most habitual pre-treatments for overcoming them. The conclusion of all of this is that it is necessary to haven a good laboratory available, one that allows for a complete analysis of the water to be treated and a system for tracking the systems once they are in operation. (Author)

  1. Application and Development of Reverse Osmosis in the Drinking Water Project in Mountains in Southern Ningxia%反渗透技术在宁夏南部山区人饮工程中的应用及发展

    Institute of Scientific and Technical Information of China (English)

    陆阳; 袁妮妮

    2014-01-01

    分析了反渗透膜的分离机理、特性及影响膜性能的主要因素,对反渗透系统在宁夏南部山区人饮工程中的应用做了分析与评价,并对其在未来的应用和发展提出自己的看法。%The paper firstly analyzes the separation mechanism and characteristics of Reverse Osmosis ( RO ) membrane and the main factors that influence membrane’ s performance. Furthermore, the application of reverse osmosis system is ana-lyzed and evaluated. Accordingly, prospects of its development and application is put forward.

  2. On softened water reverse osmosis centralized control scheme and common defect analysis%软化水反渗透系统集控方案及常见故障分析

    Institute of Scientific and Technical Information of China (English)

    张琦

    2015-01-01

    介绍了软化水反渗透系统的主要包含部分及功能,着重对该系统常见的故障进行了原因分析,主要有RO增压泵不工作、计量泵不工作、反渗透产水量下降等问题,以制定出有效的解决措施,保证系统的正常运行。%The paper introduces the main parts and functions of the softened water reverse osmosis system,analyzes reasons for common defects of the system,including the insufficiency in the RO booster pump and metering pump,and lower water yield of the reverse osmosis,so as to make the effective solutions and ensure the common operation of the system.

  3. Development on Reverse Osmosis Vessel and its Material%海水淡化用反渗透膜仓及其原材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    余启勇; 史俊虎; 林明; 张向东

    2012-01-01

    玻璃钢缠绕成型的反渗透膜仓已在工业上获得应用.本文主要介绍了国内海水淡化用反渗透膜仓的研究进展情况及反渗透膜仓的制作工艺,对适合采用缠绕成型的方法制作反渗透膜仓用的环氧树脂原材料也进行了介绍.%Filament wet-winded of pressure vessel for reverse osmosis(R0) in seawater desalination has been applied to industrialization. This paper reviews the development of the pressure vessel for reverse osmosis in China and its production process. The material of pressure vessel for RO was also introduced including high quality epoxy resin applied in wet-winding process.

  4. Research Progress of Ultrafiltration and Reverse Osmosis Technology Applied in Sugar Industry%超滤、反渗透技术在制糖业应用的研究进展

    Institute of Scientific and Technical Information of China (English)

    蒙丽霞; 李凯; 陆登俊; 陆海勤; 杭方学; 谢彩锋; 梁欣泉

    2014-01-01

    超滤、反渗透技术是应用较广泛的膜分离技术。本文介绍了超滤、反渗透技术的基本原理、发展历程及应用领域,概述了这2种膜分离技术在制糖业应用的研究进展并展望了它们在制糖业的前景。%Ultrafiltration and reverse osmosis are a widely used membrane separation technology. The fundamental principle, development and application of ultrafiltration and reverse osmosis technology are introduced, the research progress of these membrane technologies applied in the sugar industry are summarized, the outlook in future in sugar industry are put forward.

  5. BOILER MAKE-UP WATER TREATMENT USING REVERSE OSMOSIS-MIXED BED SYSTEM%采用反渗透-混床系统进行锅炉补给水处理

    Institute of Scientific and Technical Information of China (English)

    杨文君; 何新玲

    2001-01-01

    介绍了反渗透-混床除盐系统处理锅炉补给水时的运行经验。经4年的实践表明:(1)采用机械搅拌澄清池和三级过滤的系统,可以达到反渗透组件对进水水质的要求;(2)反渗透组件的脱盐率每年约降低1%~2%,在设计中必须考虑;(3)一般情况下,反渗透装置的出水应经过除碳器再送入混床;(4)混床的出力必须有足够的余量,以免影响供水。%Operational experience of boiler make-up water treatment by using reverse osmosis-mixed bed demin-eralizing system has been described. Practice during the period of four years shows: (1) Settled water pond and three-stage filtration system with mechanical agitation can meet the requitments of reverse-osmosis components to the inlet water quality; (2) It must be considered in the design that the demineralization efficiency of reverse-osmosis components will be decreased about 1%~2% in every year; (3) In normal case, the outlet water from reverse-osmosis equipment shall enter into mixed bed via a decarbonator; (4) The output capacity of the mixed bed must have a sufficient surplus, to avoid its influence on the water supply.

  6. Analysis on Fouling of Reverse Osmosis Systems in Reuse Process for Blowdown of Circulating Water%循环水排污水回用工艺中反渗透系统污堵原因分析

    Institute of Scientific and Technical Information of China (English)

    龙潇; 何彩燕; 石景燕; 侯文龙; 张宝山; 吴海峰

    2012-01-01

    The circulation water waste water reuse treatment process of a Hebei power plant was briefly introduced. A detailed test for the rapid rising pressure difference of security filter and the problem of reverse osmosis (RO) system fouling was made. The analysis results show that the local acid concentration of the reverse osmosis water plus acid point is too high. The high concentration result in the precipitation of the circulating water quality stabilizer, which plug in the security filter core surface. Thereby the micro-organisms breed, which lead to the rapid fouling in reverse osmosis system security filter. By adjusting the acid point, the phenomenon of the reverse osmosis fouling was eliminated and the system can operate normally.%简要介绍河北某电厂循环水排污水回用处理工艺.针对反渗透系统污堵及保安过滤器压差迅速上升问题进行了详细试验,逐一排查.分析结果表明,反渗透进水加酸点局部酸浓度过高,造成循环水中的水质稳定剂析出,堵在保安过滤器滤芯表面,进而引起微生物滋生,导致反渗透系统保安过滤器迅速污堵.经调整加酸点后再未出现反渗透污堵现象,系统运行正常.

  7. Dimensioning of reverse osmosis installation driven by photovoltaic panels: an experience of Coite - Pedreiras, Ceara State, Brazil; Dimensionamento de uma instalacao de osmose reversa acionada por paineis fotovoltaicos: a experiencia de Coite - Pedreiras

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Paulo Cesar Marques de; Oliveira, Ricardo Gildo Vieira de [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Engenharia Eletrica. Grupo de Processamento de Energia e Controle]. E-mail: carvalho@dee.ufc.br; ricardogildo@bol.com.br; Freire, Cristiano Augusto da Silva [ARCE, Agencia Reguladora de Servicos Publicos Delegados do Estado do Ceara, Fortaleza, CE (Brazil)]. E-mail: cristiano@arce.ce.gov.br

    2002-07-01

    The paper evaluates the dimensioning of a photovoltaic generator used for supplying electric power to a battery bank coupled to a reverse osmosis installation. The evaluation is focused on site data collected and stored by a data acquisition system. The dimensioning evaluation nis performed considering that not all the solar energy entering in panes is converted to electric power due to the using of charge control between the generator and the battery bank.

  8. 基于反渗透技术的沼液浓缩研究%Research on Concentration of Biogas Slurry Based on Reverse Osmosis

    Institute of Scientific and Technical Information of China (English)

    梁康强; 阎中; 魏泉源; 朱民; 林秀军; 陈百恒

    2012-01-01

    As for the problems of biogas slurry, such as its large amount, difficulties in disposal, storage, transport and low nutrients, the reverse osmosis (RO) technology concentrating the biogas slurry were put forward in this paper. The concentrating effect was investigated,and the quality of permeated liquid was analyzed. The results showed that the effect of the slurry concentrating by reverse osmosis technology is excellent. The concentrating effect in conductivity, COD, NH3-N were all more than 9O%, and the permeated liquid of the RO system could meet the standard for recycle use. Besides, through the tests of agricultural indicators, it was found that the nutrients of concentrated slurry was 4 times as that in the original slurry,so that the application of concentrated slurry can achieve the equivalent effect of regular fertilizer. Simultaneously, the concentrated slurry has advantages in controlling pest,promoting crop growth, increasing crop yield. Therefore,it has the potential for further commercial use.%文章针对沼气工程中沼液产量大、处理成本高、储存运输困难和营养物质含量偏低等问题,提出采用高耐污反渗透技术对沼液进行浓缩的建议.实验分析了沼液的浓缩效果,考察了浓缩后透过液水质.实验结果表明,反渗透技术对沼液浓缩效果良好,对电导率,COD,NH3-N的浓缩效果达90%以上,透过液水质能够达到调浆等回用标准.通过对浓缩液农用指标的测试发现,浓缩液所含营养物质是原液的4倍,可以实现普通肥料等效施用效果,并在病虫害防治、促进作物生长、提高作物产量方面具有优势,有进一步商业化利用的潜力.

  9. Waste water regeneration technologies: the experience of a pilot plant using an MBR process and micro-ultrafiltration and reverse osmosis in the waste water treatment plant at Canals-Lucidol de Cre spins (Valencia, Spain); Tecnologias para la regeneracion de aguas residuales: experiencia con planta piloto mediante un proceso MBR y membranas de micro-ultrafiltracion y osmosis inversa en la EDAR de Canals-L' Alcudia de Crespins (Valencia)

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Muro, J. L.; Garcia Garcia, J. J.; Morenilla Martinez, J. J.; Bernacer Bonora, I.; Lloret Salinas, R.; Pascual Garrido, J.; Escribano Romero, F.; Zarzo Martinez, D.

    2006-07-01

    This article looks at membrane bioreactor (MBR) technology and the use of micro-ultrafiltration membranes systems for treating sewage prior to reverse osmosis to desalinate sewage plant affluent. MBR technology ensures stable effluent quality (it is not affected by problems of sedimentation of the biological sludge in the clarifier) and practical disinfecting of the sludge. Micro-ultra-filtration technologies, either as treatment prior to reverse osmosis, or as independent tertiary treatment systems, generally guarantee extremely demanding permeate characteristics: SDI15 < 3-fouling index-, absence of microbiological organisms, and cloudines < 1 NTU. (Author)

  10. 反渗透对模拟放射性废水中镍的截留性能研究%Research on Rejection Performance of Reverse Osmosis to Nickel in Simulated Radioactive Wastewater

    Institute of Scientific and Technical Information of China (English)

    孔劲松; 王晓伟

    2013-01-01

    In order to reveal the rejection performance of the reverse osmosis applied in the radioactive wastewater treatment, treatment experiments were carried out on a pilot reverse osmosis equipment using wastewater containing nickel nuclide. Results showed that the rejection ratio of reverse osmosis to nickel was almost not affected by the operation pressure and the ratio of reclaiming, and had no direct relation with the salt rejection ratio. The ratio of nickel rejection reached 95% in the experiment condition and could meet the requirement on the disposal of radioactive wastewater produced by nuclear powered installations.%为了研究反渗透对放射性废水中核素的截留性能,配制含镍的模拟废水在小型装置上进行处理实验.结果表明:反渗透对于镍的截留率受操作压力和回收率的影响甚小,且与反渗透脱盐率之间也没有直接的关系,在实验条件下反渗透对废水中镍的截留率在95%以上,能够满足压水堆放射性废水处理的要求.

  11. Application of Electric Pulse-coagulation Treatment Method in Reverse Osmosis Concentrated Water Treatment%电脉冲-混凝处理法在反渗透浓水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    于玥; 邓柏杰

    2015-01-01

    文章以炼油厂反渗透浓缩水为研究对象,采用电脉冲—混凝法处理炼油厂反渗透浓水。选择聚环氧乙烷作为助凝剂,采用电脉冲—聚环氧乙烷混凝处理反渗透浓水,确定优化参数,分析和讨论实验现象和实验结果。%Taking reverse osmosis concentrated water as the research object in refinery,reverse osmosis concentrated water is treated by electric pulse-coagulation treatment in refinery.The choice of polyethylene oxide as a coagulant,the electric pulse-polyethylene oxide coagulation treatment of concentrated water reverse osmosis,determining the optimal parameter;the experimental phenomena and experimental results are analyzed and discussed in the paper.

  12. Removing organic and nitrogen content from a highly saline municipal wastewater reverse osmosis concentrate by UV/H2O2-BAC treatment.

    Science.gov (United States)

    Pradhan, Shovana; Fan, Linhua; Roddick, Felicity A

    2015-10-01

    Reverse osmosis (RO) concentrate (ROC) streams generated from RO-based municipal wastewater reclamation processes pose potential health and environmental risks on their disposal to confined water bodies such as bays. A UV/H2O2 advanced oxidation process followed by a biological activated carbon (BAC) treatment was evaluated at lab-scale for the removal of organic and nutrient content from a highly saline ROC (TDS 16 g L(-1), EC 23.5 mS cm(-1)) for its safe disposal to the receiving environment. Over the 230-day operation of the UV/H2O2-BAC process, the colour and UV absorbance (254 nm) of the ROC were reduced to well below those of the influent to the reclamation process. The concentrations of DOC and total nitrogen (TN) were reduced by approximately 60% at an empty bed contact time (EBCT) of 60 min. The reduction in ammonia nitrogen by the BAC remained high under all conditions tested (>90%). Further investigation confirmed that the presence of residual peroxide in the UV/H2O2 treated ROC was beneficial for DOC removal, but markedly inhibited the activities of the nitrifying bacteria (i.e., nitrite oxidising bacteria) in the BAC system and hence compromised total nitrogen removal. This work demonstrated that the BAC treatment could be acclimated to the very high salinity environment, and could be used as a robust method for the removal of organic matter and nitrogen from the pre-oxidised ROC under optimised conditions.

  13. In-depth analyses of organic matters in a full-scale seawater desalination plant and an autopsy of reverse osmosis membrane

    KAUST Repository

    Jeong, Sanghyun

    2016-02-17

    In order to facilitate the global performance of seawater reverse osmosis (SWRO) systems, it is important to improve the feed water quality before it enters the RO. Currently, many desalination plants experience production losses due to incidents of organic and biofouling. Consequently, monitoring or characterizing the pretreatment step using more advanced organic and biological parameters are required for better operation to lessen fouling issues. In this study, the performance of pretreatment processes (including coagulation, dual media filtration (DMF), polishing with cartridge filter (CF) coupled with anti-scalant) used at Perth Seawater Desalination Plant (PSDP) located in Western Australia were characterized in terms of organic and biological fouling parameters. These analyses were carried out using liquid chromatography with organic carbon detector (LC-OCD), three dimensional-fluorescence excitation emission matrix (3D-FEEM) and assimilable organic carbon (AOC). Furthermore, the used (exhausted) RO membrane and CF were autopsied so that the fates and behaviors of organic foulants in these treatment systems could be better understood.

  14. Dynamics of microbial communities in an integrated ultrafiltration–reverse osmosis desalination pilot plant located at the Arabian Gulf

    KAUST Repository

    Hong, Pei-Ying

    2015-08-27

    This study demonstrated the use of high-throughput sequencing to assess the efficacy of an integrated ultrafiltration (UF)–reverse osmosis (RO) desalination pilot plant located at the Arabian Gulf, and to identify potential microbial-associated problems that may arise in this plant. When integrated into the desalination treatment system, the UF membranes were able to serve as a good pretreatment strategy to delay RO fouling by achieving up to 1.96-log removal of cells from the seawater. Consequently, the differential pressure of the RO membrane remained around 1 bar for the entire six-month study, suggesting no significant biofouling performance issue identified for this RO system. Examples of microbial populations effectively removed by the UF membranes from the feed waters included Nitrosoarchaeum limnia and phototrophic eukaryotes. Microbial-associated problems observed in this pilot plant included the presence of Pseudomonas spp. in coexistence with Desulfovibrio spp. These two bacterial populations can reduce sulfate and produce hydrogen sulfide, which would in turn cause corrosion problems or compromise membrane integrities. Chemical-enhanced backwashing (CEB) can be used as an effective strategy to minimize the associated microbial problems by removing bacterial populations including sulfate reducers from the UF membranes.

  15. Evaluating a strategy for maintaining nitrifier activity during long-term starvation in a moving bed biofilm reactor (MBBR) treating reverse osmosis concentrate.

    Science.gov (United States)

    Ye, Liu; Hu, Shihu; Poussade, Yvan; Keller, Jurg; Yuan, Zhiguo

    2012-01-01

    A two-stage moving bed biofilm reactor (MBBR) was applied at the Bundamba advanced water treatment plant (AWTP) (Queensland, Australia) to treat the reverse osmosis concentrate (ROC) for inorganic nutrient removal. One of the operational challenges for the system was to cope with the large fluctuations of the ROC flow. This study investigated the decay rates of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) and biofilm detachment in MBBR during starvation for up to one month. An intermittent aeration strategy of 15 min aeration every 6 h was applied. This study also evaluated the activity recovery of both AOB and NOB after normal operation was resumed. The results showed that the activity loss of AOB and NOB was relatively minor (<20%) within 10 days of starvation, which ensured relatively quick recovery of ammonium removal when normal operation resumed. In contrast, the AOB and NOB activity loss reached 60-80% when the starvation time was longer than 20 days, resulting in slower recovery of ammonium removal after starvation. Starvation for less than 20 days didn't result in an apparent biomass detachment from carriers.

  16. 印染废水回用的连续微滤/反渗透技术%Continuous microfiltration/reverse osmosis technique for reuse of dyeing effluents

    Institute of Scientific and Technical Information of China (English)

    张云

    2012-01-01

    Advanced treatment of dyeing wastewater is carried out with continuous micro filtration (CMF)and reverse osmosis (RO) combined process, and its effect is studied. The results show that the system of the combined process with CMF and RO works smoothly,and can effectively remove over 98% of the total CODcr, chromaticity, turbidity and conductivity. The water quality of RO effluent is superior to that of tap water. The main water quality indexes of the treated water can meet the demands of dyeing and printing process.%采用连续微滤(CMF)+反渗透(RO)技术对印染废水进行深度处理,研究CMF+ RO集成工艺的处理效果.试验结果表明,CMF+ RO处理系统运行稳定,对CODCr、色度、浊度、电导率的去除率均达98%以上,RO出水水质优于自来水,各项水质指标均满足印染工艺回用水的要求.