WorldWideScience

Sample records for contaminant pulse removal

  1. Regenerable Contaminant Removal System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Regenerable Contaminant Removal System (RCRS) is an innovative method to remove sulfur and halide compounds from contaminated gas streams to part-per-billion...

  2. Contaminant Removal From Natural Resources

    Science.gov (United States)

    Clausen, Christian A. (Inventor); Quinn, Jacqueline W. (Inventor); Geiger, Cheri L. (Inventor); Reinhart, Debra (Inventor); Fillpek, Laura B. (Inventor); Coon, Christina (Inventor); Devor, Robert (Inventor)

    2006-01-01

    A zero-valent metal emulsion containing zero-valent metal particles is used to remediate contaminated natural resources, such as groundwater and soil. In a preferred embodiment, the zero-valent metal emulsion removes heavy metals, such as lead (pb), from contaminated natural resources. In another preferred embodiment, the zero-valent metal emulsion is a bimetallic emulsion containing zero-valent metal particles doped with a catalytic metal to remediate halogenated aromatic compounds, such as polychlorinated biphenyls (PCBs), from natural resources.

  3. Method of removing contaminants from plastic resins

    Science.gov (United States)

    Bohnert,George W.; Hand,Thomas E.; Delaurentiis,Gary M.

    2007-08-07

    A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

  4. Method for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2008-12-30

    A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

  5. Methods for removing contaminants from algal oil

    Energy Technology Data Exchange (ETDEWEB)

    Lupton, Francis Stephen

    2016-09-27

    Methods for removing contaminants from algal oil are provided. In an embodiment, a method comprises the steps of combining a sulfuric acid-aqueous solution that has a pH of about 1 or less with a contaminant-containing algal oil at treatment conditions effective to form an effluent. The effluent comprises a treated algal oil phase and contaminants in an acidic aqueous phase. The contaminants comprise metals, phosphorus, or combinations thereof. The acidic aqueous phase is removed from the effluent to form a contaminant-depleted algal oil.

  6. Methods for removing contaminants from algal oil

    Science.gov (United States)

    Lupton, Francis Stephen

    2016-09-27

    Methods for removing contaminants from algal oil are provided. In an embodiment, a method comprises the steps of combining a sulfuric acid-aqueous solution that has a pH of about 1 or less with a contaminant-containing algal oil at treatment conditions effective to form an effluent. The effluent comprises a treated algal oil phase and contaminants in an acidic aqueous phase. The contaminants comprise metals, phosphorus, or combinations thereof. The acidic aqueous phase is removed from the effluent to form a contaminant-depleted algal oil.

  7. System for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2010-11-23

    A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

  8. Removal of radioactive contaminants by polymeric microspheres.

    Science.gov (United States)

    Osmanlioglu, Ahmet Erdal

    2016-11-01

    Radionuclide removal from radioactive liquid waste by adsorption on polymeric microspheres is the latest application of polymers in waste management. Polymeric microspheres have significant immobilization capacity for ionic substances. A laboratory study was carried out by using poly(N-isopropylacrylamide) for encapsulation of radionuclide in the liquid radioactive waste. There are numbers of advantages to use an encapsulation technology in radioactive waste management. Results show that polymerization step of radionuclide increases integrity of solidified waste form. Test results showed that adding the appropriate polymer into the liquid waste at an appropriate pH and temperature level, radionuclide was encapsulated into polymer. This technology may provide barriers between hazardous radioactive ions and the environment. By this method, solidification techniques became easier and safer in nuclear waste management. By using polymer microspheres as dust form, contamination risks were decreased in the nuclear industry and radioactive waste operations.

  9. Aqueous adsorption and removal of organic contaminants by carbon nanotubes.

    Science.gov (United States)

    Yu, Jin-Gang; Zhao, Xiu-Hui; Yang, Hua; Chen, Xiao-Hong; Yang, Qiaoqin; Yu, Lin-Yan; Jiang, Jian-Hui; Chen, Xiao-Qing

    2014-06-01

    Organic contaminants have become one of the most serious environmental problems, and the removal of organic contaminants (e.g., dyes, pesticides, and pharmaceuticals/drugs) and common industrial organic wastes (e.g., phenols and aromatic amines) from aqueous solutions is of special concern because they are recalcitrant and persistent in the environment. In recent years, carbon nanotubes (CNTs) have been gradually applied to the removal of organic contaminants from wastewater through adsorption processes. This paper reviews recent progress (145 studies published from 2010 to 2013) in the application of CNTs and their composites for the removal of toxic organic pollutants from contaminated water. The paper discusses removal efficiencies and adsorption mechanisms as well as thermodynamics and reaction kinetics. CNTs are predicted to have considerable prospects for wider application to wastewater treatment in the future.

  10. Removal of emerging organic contaminants in a poplar vegetation filter

    NARCIS (Netherlands)

    Martínez Hernández, V.; Lealb, M.; Meffe, R.; Miguel Garcia, de Angel; Alonso-Alonso, C.; Bustamante, de I.; Lillo, J.; Martín, I.; Salas, J.J.

    2017-01-01

    Vegetation filters (VFs), a type of land application system, are a robust technology based on natural treatment mechanisms for the removal of wastewater contaminants. Their capacity to attenuate emerging organic contaminants (EOCs) has not yet been evaluated. The present study reports the results

  11. Unbiased contaminant removal for 3D galaxy power spectrum measurements

    CERN Document Server

    Kalus, Benedict; Bacon, David; Samushia, Lado

    2016-01-01

    We assess and develop techniques to remove contaminants when calculating the 3D galaxy power spectrum. We separate the process into three separate stages: (i) removing the contaminant signal, (ii) estimating the uncontaminated cosmological power spectrum, (iii) debiasing the resulting estimates. For (i), we show that removing the best-fit contaminant (template subtraction), and setting the contaminated components of the covariance to be infinite (mode deprojection) are mathematically equivalent. For (ii), performing a Quadratic Maximum Likelihood (QML) estimate after mode deprojection gives an optimal unbiased solution, although it requires the manipulation of large $(N_{\\rm mode}^2)$ matrices, which is unfeasible for recent 3D galaxy surveys. Measuring a binned average of the modes for (ii) as proposed by Feldman, Kaiser & Peacock (1994, FKP) is faster and simpler, but is sub-optimal and gives rise to a biased solution. We present a method to debias the resulting FKP measurements that does not require an...

  12. Feed gas contaminant removal in ion transport membrane systems

    Science.gov (United States)

    Underwood, Richard Paul [Allentown, PA; Makitka, III, Alexander; Carolan, Michael Francis [Allentown, PA

    2012-04-03

    An oxygen ion transport membrane process wherein a heated oxygen-containing gas having one or more contaminants is contacted with a reactive solid material to remove the one or more contaminants. The reactive solid material is provided as a deposit on a support. The one or more contaminant compounds in the heated oxygen-containing gas react with the reactive solid material. The contaminant-depleted oxygen-containing gas is contacted with a membrane, and oxygen is transported through the membrane to provide transported oxygen.

  13. Ablation-cooled material removal with ultrafast bursts of pulses

    Science.gov (United States)

    Kerse, Can; Kalaycıoğlu, Hamit; Elahi, Parviz; Çetin, Barbaros; Kesim, Denizhan K.; Akçaalan, Önder; Yavaş, Seydi; Aşık, Mehmet D.; Öktem, Bülent; Hoogland, Heinar; Holzwarth, Ronald; Ilday, Fatih Ömer

    2016-09-01

    The use of femtosecond laser pulses allows precise and thermal-damage-free removal of material (ablation) with wide-ranging scientific, medical and industrial applications. However, its potential is limited by the low speeds at which material can be removed and the complexity of the associated laser technology. The complexity of the laser design arises from the need to overcome the high pulse energy threshold for efficient ablation. However, the use of more powerful lasers to increase the ablation rate results in unwanted effects such as shielding, saturation and collateral damage from heat accumulation at higher laser powers. Here we circumvent this limitation by exploiting ablation cooling, in analogy to a technique routinely used in aerospace engineering. We apply ultrafast successions (bursts) of laser pulses to ablate the target material before the residual heat deposited by previous pulses diffuses away from the processing region. Proof-of-principle experiments on various substrates demonstrate that extremely high repetition rates, which make ablation cooling possible, reduce the laser pulse energies needed for ablation and increase the efficiency of the removal process by an order of magnitude over previously used laser parameters. We also demonstrate the removal of brain tissue at two cubic millimetres per minute and dentine at three cubic millimetres per minute without any thermal damage to the bulk.

  14. Removal of trace metal contaminants from potable water by electrocoagulation

    Science.gov (United States)

    Heffron, Joe; Marhefke, Matt; Mayer, Brooke K.

    2016-06-01

    This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency.

  15. Effectiveness of fluidized pellet bed for removing soluble contaminants

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaochang; LI Zhihua; WANG Zhen; LI Jinrong; LI Jiayu; CHEN Rong

    2009-01-01

    Fluidized pellet bed (FPB) has been successfully applied in water and wastewater treatment. However, the removal mechanism of contaminants especially the soluble ones, is still unclear. This study aimed to evaluate the effectiveness of FPB reactor for removing soluble contaminants from synthetic wastewater. By only coagulation through jar test operation with addition of polyaluminium chloride (PACl) as primary coagulant and polyacryamide (PAM) as coagulant-aid, the removals of soluble chemical oxygen demand (COD), suspended solids (SS), total phosphorus (TP), and NH4+-N were found to be only 2.2%--7.5%, 5.7%--25.5%, and 9.9%--18.5%, respectively. However, by FPB operation under the same dosage of coagulants, these values increased to 82.7%, 37.2%, and 50%, indicating that the formation of pellets in the FPB effectively enhanced the removal of soluble contaminants. By careful comparison of the settleablility and filterability of the pollutants after coagulation, the originally soluble contaminants could be divided into three groups, namely: (i) coagulated-and-settleable, (ii) coagulated-but-nonsettleable, and (iii) uncoagulable. It was found that not only the first two groups but also a large part of the third group could be effectively removed by FPB operation. However, the mechanism for the removal of the uncoagulable pollutants by FPB operation still needs further investigation.

  16. Aqueous adsorption and removal of organic contaminants by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jin-Gang, E-mail: yujg@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Zhao, Xiu-Hui; Yang, Hua [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Chen, Xiao-Hong [Collaborative Innovation Center of Resource-conserving and Environment-friendly Society and Ecological Civilization, Changsha, Hunan 410083 (China); Yang, Qiaoqin [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada); Yu, Lin-Yan [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Jiang, Jian-Hui [College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082 (China); Chen, Xiao-Qing, E-mail: xqchen@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China)

    2014-06-01

    Organic contaminants have become one of the most serious environmental problems, and the removal of organic contaminants (e.g., dyes, pesticides, and pharmaceuticals/drugs) and common industrial organic wastes (e.g., phenols and aromatic amines) from aqueous solutions is of special concern because they are recalcitrant and persistent in the environment. In recent years, carbon nanotubes (CNTs) have been gradually applied to the removal of organic contaminants from wastewater through adsorption processes. This paper reviews recent progress (145 studies published from 2010 to 2013) in the application of CNTs and their composites for the removal of toxic organic pollutants from contaminated water. The paper discusses removal efficiencies and adsorption mechanisms as well as thermodynamics and reaction kinetics. CNTs are predicted to have considerable prospects for wider application to wastewater treatment in the future. - Highlights: • We summarize the most recent research progress of CNTs for removal of organics. • Adsorption mechanisms between CNTs and organics were elucidated in detail. • The developing trends and prospects of CNTs for removal of organics were discussed.

  17. Laser and intense pulsed light hair removal technologies

    DEFF Research Database (Denmark)

    Haedersdal, M; Beerwerth, F; Nash, J F

    2011-01-01

    Light-based hair removal (LHR) is one of the fastest growing, nonsurgical aesthetic cosmetic procedures in the United States and Europe. A variety of light sources including lasers, e.g. alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), Nd:YAG laser (1064 nm) and broad-spectrum intense...

  18. REMOVAL OF COPPER ELECTROLYTE CONTAMINANTS BY ADSORPTION

    Directory of Open Access Journals (Sweden)

    B Gabai

    1997-09-01

    Full Text Available Abstract - Selective adsorbents have become frequently used in industrial processes. Recent studies have shown the possibility of using adsorption to separate copper refinery electrolyte contaminants, with better results than those obtained with conventional techniques. During copper electrorefinning, many impurities may be found as dissolved metals present in the anode slime which forms on the electrode surface, accumulated in the electrolyte or incorporated into the refined copper on the cathode by deposition. In this study, synthetic zeolites, chelating resins and activated carbons were tested as adsorbents to select the best adsorbent performance, as well as the best operating temperature for the process. The experimental method applied was the finite bath, which consists in bringing the adsorbent into contact with a finite volume of electrolyte while controlling the temperature. The concentration of metals in the liquid phase was continuously monitored by atomic absorption spectrophotometry (AAS

  19. Method for removal of beryllium contamination from an article

    Science.gov (United States)

    Simandl, Ronald F.; Hollenbeck, Scott M.

    2012-12-25

    A method of removal of beryllium contamination from an article is disclosed. The method typically involves dissolving polyisobutylene in a solvent such as hexane to form a tackifier solution, soaking the substrate in the tackifier to produce a preform, and then drying the preform to produce the cleaning medium. The cleaning media are typically used dry, without any liquid cleaning agent to rub the surface of the article and remove the beryllium contamination below a non-detect level. In some embodiments no detectible residue is transferred from the cleaning wipe to the article as a result of the cleaning process.

  20. Treatment System for Removing Halogenated Compounds from Contaminated Sources

    Science.gov (United States)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Yestrebsky, Cherie L. (Inventor)

    2015-01-01

    A treatment system and a method for removal of at least one halogenated compound, such as PCBs, found in contaminated systems are provided. The treatment system includes a polymer blanket for receiving at least one non-polar solvent. The halogenated compound permeates into or through a wall of the polymer blanket where it is solubilized with at least one non-polar solvent received by said polymer blanket forming a halogenated solvent mixture. This treatment system and method provides for the in situ removal of halogenated compounds from the contaminated system. In one embodiment, the halogenated solvent mixture is subjected to subsequent processes which destroy and/or degrade the halogenated compound.

  1. Removal of lead contaminated dusts from hard surfaces.

    Science.gov (United States)

    Lewis, Roger D; Condoor, Sridhar; Batek, Joe; Ong, Kee Hean; Backer, Denis; Sterling, David; Siria, Jeff; Chen, John J; Ashley, Peter

    2006-01-15

    Government guidelines have widely recommended trisodium phosphate (TSP) or "lead-specific" cleaning detergents for removal of lead-contaminated dust (LCD) from hard surfaces, such as floors and window areas. The purpose of this study was to determine if low-phosphate, non-lead-specific cleaners could be used to efficiently remove LCD from 3 types of surfaces (vinyl flooring, wood, and wallpaper). Laboratory methods were developed and validated for simulating the doping, embedding, and sponge cleaning of the 3 surface types with 4 categories of cleaners: lead-specific detergents, nonionic cleaners, anionic cleaners, and trisodium phosphate (TSP). Vinyl flooring and wood were worn using artificial means. Materials were ashed, followed by ultrasound extraction, and anodic stripping voltammetry (ASV). One-way analysis of variance approach was used to evaluate the surface and detergent effects. Surface type was found to be a significant factor in removal of lead (p < 0.001). Vinyl flooring cleaned better than wallpaper by over 14% and wood cleaned better than wallpaper by 13%. There was no difference between the cleaning action of vinyl flooring and wood. No evidence was found to support the use of TSP or lead-specific detergents over all-purpose cleaning detergents for removal of lead-contaminated dusts. No-phosphate, non-lead-specific detergents are effective in sponge cleaning of lead-contaminated hard surfaces and childhood lead prevention programs should consider recommending all-purpose household detergents for removal of lead-contaminated dust after appropriate vacuuming.

  2. Removal of Particulate Contamination from Solid Surfaces Using Polymeric Micropillars.

    Science.gov (United States)

    Izadi, Hadi; Dogra, Navneet; Perreault, François; Schwarz, Cynthia; Simon, Stefan; Vanderlick, T Kyle

    2016-07-06

    This Research Article describes a novel method for removal of particulate contamination, loosely referred to as dust, from solid surfaces using polymeric micropillars. In this Research Article, we illustrate for the first time that polymeric microfibrils of controlled interfacial and geometrical properties can effectively remove micrometric and submicrometric contaminant particles from a solid surface without damaging the underlying substrate. Once these microfibrils are brought into contact with a contaminated surface, because of their their soft and flexible structure, they develop intimate contact with both the surface contaminants and the substrate. While these intrinsically nonsticky micropillars have minimal interfacial interactions with the substrate, we show that they produce strong interfacial interactions with the contaminant particles, granting the detachment of the particles from the surface upon retraction of the cleaning material. The origin and strength of the interfacial interactions at the interfaces between a contaminant particle and both the substrate and the cleaning materials are thoroughly discussed. Unlike flat substrates of the same material, using microfibrillar structures of controlled interfacial and geometrical properties also allows the elimination of the adsorbed particles from the contact interface. Here we demonstrate that by moving the adsorbed particles from the tip to the side of the fibrils and consequently removing them from the contact interface, polymeric microfibrils can clean all contaminant particles from the surface. The effects of the geometrical and interfacial properties of polymeric micropillars on removing the adsorbed particles from the tips of the pillars are fully discussed. This research is not only important in terms of introducing a novel method which can offer a new paradigm for thorough yet nondestructive cleaning of dust particles from solid surfaces, but also it is of fundamental significance for researchers

  3. Effects of pulsed and oscillatory flow on water vapor removal from a laboratory soil column. Final report, November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, K.E.

    1993-05-01

    Subsurface contamination by volatile organic contaminants (VOC`s) in the vadose zone and groundwater is primarily due to leaking underground storage tanks and industrial spills. Soil vapor extraction is a technique that is being used successfully to remove VOC`s from the subsurface. A flow of air is established through the soil to remove the vapor phase component of the contaminant. Soil vapor extraction will initially remove high levels of contaminant that is already present in the macropores. The concentration will start to decline as the removal from the soil matrix becomes limited by diffusion of contaminant from regions away from the air flow paths. This study examines potential methods of overcoming the diffusion limitation by adding an oscillatory component to the steady air flow and by pulsed flow, which involves turning air flow on and off at predetermined intervals. The study considered only the removal of water from the soil to try to establish general vapor behavior in the soil under the imposed conditions. Based on a statistical analysis, both the oscillatory and pulsed flow showed an improved water removal rate over the steady state flow. The effect of oscillatory flow was only examined at higher frequencies. The literature indicates that oscillations at lower frequencies may be more effective. Pulsed flow showed the most efficient removal of water compared to steady state conditions. The pulsed flow was most efficient because rather than reducing the diffusion limitation, the system would shut down and wait for diffusion to occur. This optimizes energy consumption, but does not reduce treatment time. The oscillatory flow actually reduced the diffusion limitation within the column which could result in a shorter treatment time.

  4. Removal of metal ions from contaminated water using agricultural residues

    Science.gov (United States)

    Roger M. Rowell

    2006-01-01

    As the world population grows, there is a growing awareness that our environment is getting more polluted. Clean water is becoming a critical issue for many parts of the world for human, animal and agricultural use. Filtration systems to clean our air and water are a growing industry. There are many approaches to removing contaminates from our water supply ranging from...

  5. Removal of low concentration contaminant species using photocatalysis

    DEFF Research Database (Denmark)

    Nielsen, Morten Godtfred; Vesborg, Peter Christian Kjærgaard; Hansen, Ole

    2015-01-01

    A photocatalytic model reactor system has been devised to assess the capacity and feasibility of a photocatalytic unit for the removal of trace amounts of organic contaminants in air. Realistic operating conditions are applied, and a mathematical model based on Langmuir–Hinselwood adsorbtion perm...

  6. Reduction in operatory mercury levels after contamination or amalgam removal.

    Science.gov (United States)

    Ferracane, J L; Engle, J H; Okabe, T; Mitchem, J C

    1994-04-01

    The threshold limit value (TLV) for occupational exposure to mercury can be exceeded in the dental operatory after a contamination event or during certain dental procedures. The objective of this study was to determine the time required for the mercury vapor levels to return to baseline in both non-ventilated and ventilated operatories after they had been contaminated with mercury to the TLV of 0.050 mg/m3; and to evaluate the efficiency of an activated charcoal filtering device for removing mercury vapor. The results showed that even in a poorly ventilated operatory, the mercury vapor level returned to background within 20-30 minutes after a contamination, and within 10-20 minutes when the operatory was ventilated. The filtering device reduced the level of mercury vapor by approximately 25% during a continuous contamination event, but did not clear the operatory faster than normal settling after a limited source contamination. The filter caused a significant reduction in mercury in the breathing zones of the patient and dentist during and after amalgam removal, but did not eliminate the exposure. This study demonstrated the difficulty in contaminating an operatory with mercury vapor and confirmed the limited time mercury remains airborne, presumably due to its density and affinity for surfaces.

  7. Electrokinetics removal of lead from lead-contaminated red soils

    Institute of Scientific and Technical Information of China (English)

    刘云国; 李欣; 曾光明; 黄宝荣; 张慧智

    2003-01-01

    Ex-situ electroremediation tests were conducted on the lead-contaminated red soils to find out the optimum condition for the most efficient removal of lead pollution from the red soil,and to examine the relation of the pH of the soil with the electroremediation efficiency.The results show that the electroremediation technology is efficient to remedy Pb contaminated red soils,and the removal efficiency can be enhanced by controlling pH value in the cathode reservoir with HNO3.The average removal efficiency of Pb is enhanced from 24.5% to 79.5%,and the energy consumption reaches 285kW·h per m3 red soil.

  8. Laser and intense pulsed light hair removal technologies

    DEFF Research Database (Denmark)

    Haedersdal, M; Beerwerth, F; Nash, J F

    2011-01-01

    Light-based hair removal (LHR) is one of the fastest growing, nonsurgical aesthetic cosmetic procedures in the United States and Europe. A variety of light sources including lasers, e.g. alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), Nd:YAG laser (1064 nm) and broad-spectrum intense...... and discuss the efficacy and human safety implications of home-use devices....

  9. Removal of metals by sorghum plants from contaminated land

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Ping; SHU Wensheng; LI Zhian; LIAO Bin; LI Jintian; SHAO Jingsong

    2009-01-01

    The growth of high biomass crops facilitated by optimization of agronomic practices has been considered as an alternative to phytoremediation of soils contaminated by heavy metals. A field trial was carried out to evaluate the phytoextraction efficiency of heavy metals by three varieties of sweet sorghum (Sorghum biocolor L.), a high biomass energy plant. Ethylene diamine tetraacetate (EDTA), ammonium nitrate (NH4NO3) and ammonium sulphate ((NH4)2SO4) were tested for their abilities to enhance the removal of heavy metals Pb, Cd, Zn, and Cu by sweet sorghum from a contaminated agricultural soil. Sorghum plants always achieved the greatest removal of Pb by leaves and the greatest removal of Cd, Zn and Cu by stems. There was no significant difference among the Keller, Rio and Mray varieties of sweet sorghums in accumulating heavy metals. EDTA treatment was more efficient than ammonium nitrate and ammonium sulphate in promoting Pb accumulation in sweet sorghum from the contaminated agricultural soil. The application of ammonium nitrate and ammonium sulphate increased the accumulation of both Zn and Cd in roots of sorghum plants. Results from this study suggest that cropping of sorghum plants facilitated by agronomic practices may be a sustainable technique for partial decontamination of heavy metal contaminated soils.

  10. Removal of metals by sorghum plants from contaminated land.

    Science.gov (United States)

    Zhuang, Ping; Shu, Wensheng; Li, Zhian; Liao, Bin; Li, Jintian; Shao, Jingsong

    2009-01-01

    The growth of high biomass crops facilitated by optimal of agronomic practices has been considered as an alternative to phytoremediation of soils contaminated by heavy metals. A field trial was carried out to evaluate the phytoextraction efficiency of heavy metals by three varieties of sweet sorghum (Sorghum biocolor L.), a high biomass energy plant. Ethylene diamine tetraacetate (EDTA), ammonium nitrate (NH4NO3) and ammonium sulphate ((NH4)2SO4) were tested for their abilities to enhance the removal of heavy metals Pb, Cd, Zn, and Cu by sweet sorghum from a contaminated agricultural soil. Sorghum plants always achieved the greatest removal of Pb by leaves and the greatest removal of Cd, Zn and Cu by stems. There was no significant difference among the Keller, Rio and Mray varieties of sweet sorghums in accumulating heavy metals. EDTA treatment was more efficient than ammonium nitrate and ammonium sulphate in promoting Pb accumulation in sweet sorghum from the contaminated agricultural soil. The application of ammonium nitrate and ammonium sulphate increased the accumulation of both Zn and Cd in roots of sorghum plants. Results from this study suggest that cropping of sorghum plants facilitated by agronomic practices may be a sustainable technique for partial decontamination of heavy metal contaminated soils.

  11. Synchronous pulsing plasma utilization in dummy poly gate removal process

    Science.gov (United States)

    Huang, Ruixuan; Meng, Xiao-Ying; Han, Qiu-Hua; Zhang, Hai-Yang

    2015-03-01

    When CMOS technology reaches 28/20nm node and beyond, several new schemes are implemented such as High K metal gate (HKMG) which can enhance the device performance and has better control of device current leakage. Dummy poly gate removal (DPGR) process is introduced for HKMG, and works as a key process to control the work function of metal gate and threshold voltage (Vt) shift. In dry etch technology, conventional continuous wave (CW) plasma process has been widely used, however, it may not be capable for some challenging process in 28nm node and beyond. In DPGR process for HKMG scheme, CW scheme may result in plasma damage of gate oxide/capping layer for its inherent high electron temperature (Te) and ion energy while synchronous pulsing scheme is capable to simultaneously pulse both source and bias power, which could achieve lower Te, independent control of ion and radical flux, well control the loading of polymer deposition on dense/ isolate features. It's the first attempt to utilize synchronous pulsing plasma in DPGR process. Experiment results indicate that synchronous pulsing could provide less silicon recess under thin gate oxide which is induced by the plasma oxidation. Furthermore, the loading of HK capping layer loss between long channel and short channel can be well controlled which plays a key role on transistor performance, such as leakage and threshold voltage shift. Additionally, it has been found that synchronous pulsing could distinctly improve ILD loss when compared with CW, which is helpful to broaden the whole process window.

  12. Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

    Science.gov (United States)

    Anpilov, A M; Barkhudarov, E M; Christofi, N; Kop'ev, V A; Kossyi, I A; Taktakishvili, M I; Zadiraka, Y

    2002-01-01

    To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

  13. Arsenic removal from contaminated soil using phosphoric acid and phosphate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Laboratory batch experiments were conducted to study Arsenic (As) removal from a naturally contaminated soil using phosphoric acid (H3PO4) and potassium dihydrogen phosphate (KH2PO4). Both H3PO4 and KH2PO4 proved to clearly reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L, although soil As tolerance limit of 30 mg/kg, according to Chinese Environmental quality standard for soil (EQSS), was not satisfied by using these two extractants. At the same time, acidification of soil and dissolution of soil components (Ca, Mg, and Si) resulted from using these two extractants, especially H3PO4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions (PO43-). The function of H3PO4 as an acid to dissolve soil components had little effects on As removal. KH2PO4 almost removed as much As as H3PO4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 min, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich's model best described the kinetic data of As removal among the four models used in the kinetic study.

  14. Cadmium removal from contaminated soil by tunable biopolymers.

    Science.gov (United States)

    Prabhukumar, Giridhar; Matsumoto, Mark; Mulchandani, Ashok; Chen, Wilfred

    2004-06-01

    An elastin-like polypeptide (ELP) composed of a polyhistidine tail (ELPH12) was exploited as a tunable, metal-binding biopolymer with high affinity toward cadmium. By taking advantage of the property of ELPH12 to undergo a reversible thermal precipitation, easy recovery of the sequestered cadmium from contaminated water was demonstrated as the result of a simple temperature change. In this study, batch soil washing experiments were performed to evaluate the feasibility of using ELPH12 as an environmentally benign strategy for removing cadmium from contaminated soil. The stability constant (log KL) for the cadmium-ELPH12 complex was determined to be 6.8, a value similar to that reported for the biosurfactant rhamnolipid. Two washings with 1.25 mg/mL of ELPH12 were able to remove more than 55% of the bound cadmium as compared to only 8% removal with ELP containing no histidine tail or 21% removal using the same concentration of EDTA. Unlike rhamnolipid from Pseudomonas aeruginosa ATCC 9027, which adsorbs extensively to soil, less than 10% of ELPH12 was adsorbed under all soil washing conditions. As a result, a significantly lower concentration of ELPH12 (0.036 mM as compared to 5-10 mM of biosurfactants) was required to achieve similar extraction efficiencies. However, cadmium recovery by simple precipitation was incomplete due to the displacement of bound cadmium by zinc ions present in soil. Owing to its benign nature, ease of production, and selective tailoring of the metal binding domain toward any target metals of interest, ELP biopolymers may find utility as an effective extractant for heavy metal removal from contaminated soil or ore processing.

  15. Assessing Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    Science.gov (United States)

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved PAHs and PCBs in the water column prior...

  16. Environmental projects. Volume 14: Removal of contaminated soil and debris

    Science.gov (United States)

    Kushner, Len

    1992-01-01

    Numerous diverse activities at the Goldstone Deep Space Communications Complex (GDSCC) are carried out in support of six parabolic dish antennas. Some of these activities can result in possible spills or leakages of hazardous materials and wastes stored both above ground in steel drums and below ground in underground storage tanks (UST's). These possible leaks or spills, along with the past practice of burial of solid debris and waste in trenches and pits, could cause local subsurface contamination of the soil. In 1987, the Jet Propulsion Laboratory (JPL), retained Engineering-Science, Inc. (E-S), Pasadena, California, to identify the specific local areas within the GDSCC with subsurface soil contamination. The E-S study determined that some of the soils at the Apollo Site and the Mars Site were contaminated with hydrocarbons, while soil at a nonhazardous waste dumpsite at the Mojave Base site was contaminated with copper. This volume is a JPL-expanded version of the PE209 E-S report, and it also reports that all subsurface contaminated soils at the GDSCC were excavated, removed, and disposed of in an environmentally acceptable way, and the excavations were backfilled and covered in accordance with accepted Federal, State, and local environmental rules and regulations.

  17. Removal of paper microbial contamination by atmospheric pressure DBD discharge

    Science.gov (United States)

    Vrajova, J.; Chalupova, L.; Novotny, O.; Cech, J.; Krcma, F.; Stahel, P.

    2009-08-01

    In this paper the removal of the microbial contamination from paper material using the plasma treatment at atmospheric pressure is investigated. The Aspergillus niger has been chosen as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. Dielectric barrier discharge (DBD) operated at atmospheric pressure was used for the paper sterilization. The working gas (nitrogen, argon and helium), plasma exposition time and the plasma power density were varied in order to see the effect of the plasma treatment on the fungi removal. After the treatment, the microbial abatement was evaluated by the standard plate count method. This proved a positive effect of the DBD plasma treatment on fungi removal. Morphological and colorimetric changes of paper substrate after plasma treatment were also investigated.

  18. Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant Sedum alfredii

    Science.gov (United States)

    Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons(PAHs) co-contaminated s...

  19. Nitrogen limited biobarriers remove atrazine from contaminated water: Laboratory studies

    Science.gov (United States)

    Hunter, William J.; Shaner, Dale L.

    2009-01-01

    Atrazine is one of the most frequently used herbicides. This usage coupled with its mobility and recalcitrant nature in deeper soils and aquifers makes it a frequently encountered groundwater contaminant. We formed biobarriers in sand filled columns by coating the sand with soybean oil; after which, we inoculated the barriers with a consortium of atrazine-degrading microorganisms and evaluated the ability of the barriers to remove atrazine from a simulated groundwater containing 1 mg L - 1 atrazine. The soybean oil provided a carbon rich and nitrogen poor substrate to the microbial consortium. Under these nitrogen-limiting conditions it was hypothesized that bacteria capable of using atrazine as a source of nitrogen would remove atrazine from the flowing water. Our hypothesis proved correct and the biobarriers were effective at removing atrazine when the nitrogen content of the influent water was low. Levels of atrazine in the biobarrier effluents declined with time and by the 24th week of the study no detectable atrazine was present (limit of detection atrazine were also removed by the biobarriers; when biobarriers were fed 16.3 mg L - 1 atrazine 97% was degraded. When nitrate (5 mg L - 1 N), an alternate source of nitrogen, was added to the influent water the atrazine removal efficiency of the barriers was reduced by almost 60%. This result supports the hypothesis that atrazine was degraded as a source of nitrogen. Poisoning of the biobarriers with mercury chloride resulted in an immediate and large increase in the amount of atrazine in the barrier effluents confirming that biological activity and not abiotic factors were responsible for most of the atrazine degradation. The presence of hydroxyatrazine in the barrier effluents indicated that dehalogenation was one of the pathways of atrazine degradation. Permeable barriers might be formed in-situ by the injection of innocuous vegetable oil emulsions into an aquifer or sandy soil and used to remove atrazine from a

  20. An optimized procedure greatly improves EST vector contamination removal

    Directory of Open Access Journals (Sweden)

    Wu Huan-Bin

    2007-11-01

    Full Text Available Abstract Background The enormous amount of sequence data available in the public domain database has been a gold mine for researchers exploring various themes in life sciences, and hence the quality of such data is of serious concern to researchers. Removal of vector contamination is one of the most significant operations to obtain accurate sequence data containing only a cDNA insert from the basecalls output by an automatic DNA sequencer. Popular bioinformatics programs to accomplish vector trimming include LUCY, cross_match and SeqClean. Results In a recent study, where the program SeqClean was used to remove vector contamination from our test set of EST data compiled through various library construction systems, however, a significant number of errors remained after preliminary trimming. These errors were later almost completely corrected by simply using a re-linearized form of the cloning vector to compare against the target ESTs. The modified trimming procedure for SeqClean was also compared with the trimming efficiency of the other two popular programs, LUCY2, and cross_match. Using SeqClean with a re-linearized form of the cloning vector significantly surpassed the other two programs in all tested conditions, while the performance of the other two programs was not influenced by the modified procedure. Vector contamination in dbEST was also investigated in this study: 2203 out of the 48212 ESTs sampled from dbEST (2007-04-18 freeze were found to match sequences in UNIVEC. Conclusion Vector contamination remains a serious concern to the data quality in the public sequence database nowadays. Based on the results presented here, we feel that our modified procedure with SeqClean should be recommended to all researchers for the task of vector removal from EST or genomic sequences.

  1. 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.

  2. Nitrogen limited biobarriers remove atrazine from contaminated water: laboratory studies.

    Science.gov (United States)

    Hunter, William J; Shaner, Dale L

    2009-01-07

    Atrazine is one of the most frequently used herbicides. This usage coupled with its mobility and recalcitrant nature in deeper soils and aquifers makes it a frequently encountered groundwater contaminant. We formed biobarriers in sand filled columns by coating the sand with soybean oil; after which, we inoculated the barriers with a consortium of atrazine-degrading microorganisms and evaluated the ability of the barriers to remove atrazine from a simulated groundwater containing 1 mg L(-1) atrazine. The soybean oil provided a carbon rich and nitrogen poor substrate to the microbial consortium. Under these nitrogen-limiting conditions it was hypothesized that bacteria capable of using atrazine as a source of nitrogen would remove atrazine from the flowing water. Our hypothesis proved correct and the biobarriers were effective at removing atrazine when the nitrogen content of the influent water was low. Levels of atrazine in the biobarrier effluents declined with time and by the 24th week of the study no detectable atrazine was present (limit of detectionwater the atrazine removal efficiency of the barriers was reduced by almost 60%. This result supports the hypothesis that atrazine was degraded as a source of nitrogen. Poisoning of the biobarriers with mercury chloride resulted in an immediate and large increase in the amount of atrazine in the barrier effluents confirming that biological activity and not abiotic factors were responsible for most of the atrazine degradation. The presence of hydroxyatrazine in the barrier effluents indicated that dehalogenation was one of the pathways of atrazine degradation. Permeable barriers might be formed in-situ by the injection of innocuous vegetable oil emulsions into an aquifer or sandy soil and used to remove atrazine from a contaminated groundwater or to protect groundwater from an atrazine spill.

  3. Experimental demonstration of contaminant removal from fractured rock by boiling.

    Science.gov (United States)

    Chen, Fei; Liu, Xiaoling; Falta, Ronald W; Murdoch, Lawrence C

    2010-08-15

    This study was conducted to experimentally demonstrate removal of a chlorinated volatile organic compound from fractured rock by boiling. A Berea sandstone core was contaminated by injecting water containing dissolved 1,2-DCA (253 mg/L) and sodium bromide (144 mg/L). During heating, the core was sealed except for one end, which was open to the atmosphere to simulate an open fracture. A temperature gradient toward the outlet was observed when boiling occurred in the core. This indicates that steam was generated and a pressure gradient developed toward the outlet, pushing steam vapor and liquid water toward the outlet. As boiling occurred, the concentration of 1,2-DCA in the condensed effluent peaked up to 6.1 times higher than the injected concentration. When 38% of the pore volume of condensate was produced, essentially 100% of the 1,2-DCA was recovered. Nonvolatile bromide concentration in the condensate was used as an indicator of the produced steam quality (vapor mass fraction) because it can only be removed as a solute, and not as a vapor. A higher produced steam quality corresponds to more concentrated 1,2-DCA removal from the core, demonstrating that the chlorinated volatile compound is primarily removed by partitioning into vapor phase flow. This study has experimentally demonstrated that boiling is an effective mechanism for CVOC removal from the rock matrix.

  4. Pulsed photothermal depth profiling of tattoos undergoing laser removal treatment

    Science.gov (United States)

    Milanic, Matija; Majaron, Boris

    2012-02-01

    Pulsed photothermal radiometry (PPTR) allows noninvasive determination of temperature depth profiles induced by pulsed laser irradiation of strongly scattering biological tissues and organs, including human skin. In present study, we evaluate the potential of this technique for investigational characterization and possibly quantitative evaluation of laser tattoo removal. The study involved 5 healthy volunteers (3 males, 2 females), age 20-30 years, undergoing tattoo removal treatment using a Q-switched Nd:YAG laser. There were four measurement and treatment sessions in total, separated by 2-3 months. Prior to each treatment, PPTR measurements were performed on several tattoo sites and one nearby healthy site in each patient, using a 5 ms Nd:YAG laser at low radiant exposure values and a dedicated radiometric setup. The laser-induced temperature profiles were then reconstructed by applying a custom numerical code. In addition, each tatoo site was documented with a digital camera and measured with a custom colorimetric system (in tristimulus color space), providing an objective evaluation of the therapeutic efficacy to be correlated with our PPTR results. The results show that the laser-induced temperature profile in untreated tattoos is invariably located at a subsurface depth of 300 μm. In tattoo sites that responded well to laser therapy, a significant drop of the temperature peak was observed in the profiles obtained from PPTR record. In several sites that appeared less responsive, as evidenced by colorimetric data, a progressive shift of the temperature profile deeper into the dermis was observed over the course of consecutive laser treatments, indicating that the laser tattoo removal was efficient.

  5. Bead and Process for Removing Dissolved Metal Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Bobby L., Jr.; Bennett, Karen L.; Foster, Scott A.

    2005-01-18

    A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly (carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

  6. Wire-Mesh-Based Sorber for Removing Contaminants from Air

    Science.gov (United States)

    Perry, Jay; Roychoudhury, Subir; Walsh, Dennis

    2006-01-01

    A paper discusses an experimental regenerable sorber for removing CO2 and trace components principally, volatile organic compounds, halocarbons, and NH3 from spacecraft cabin air. This regenerable sorber is a prototype of what is intended to be a lightweight alternative to activated-carbon and zeolite-pellet sorbent beds now in use. The regenerable sorber consists mainly of an assembly of commercially available meshes that have been coated with a specially-formulated washcoat containing zeolites. The zeolites act as the sorbents while the meshes support the zeolite-containing washcoat in a configuration that affords highly effective surface area for exposing the sorbents to flowing air. The meshes also define flow paths characterized by short channel lengths to prevent excessive buildup of flow boundary layers. Flow boundary layer resistance is undesired because it can impede mass and heat transfer. The total weight and volume comparison versus the atmosphere revitalization equipment used onboard the International Space Station for CO2 and trace-component removal will depend upon the design details of the final embodiment. However, the integrated mesh-based CO2 and trace-contaminant removal system is expected to provide overall weight and volume savings by eliminating most of the trace-contaminant control equipment presently used in parallel processing schemes traditionally used for spacecraft. The mesh-based sorbent media enables integrating the two processes within a compact package. For the purpose of regeneration, the sorber can be heated by passing electric currents through the metallic meshes combined with exposure to space vacuum. The minimal thermal mass of the meshes offers the potential for reduced regeneration-power requirements and cycle time required for regeneration compared to regenerable sorption processes now in use.

  7. Removal of Pyrene from Contaminated Soils by White Clover

    Institute of Scientific and Technical Information of China (English)

    XU Sheng-You; CHEN Ying-Xu; LIN Kuang-Fei; CHEN Xin-Cai; LIN Qi; LI Feng; WANG Zhao-Wei

    2009-01-01

    Phytoremediation has been used as an emerging technology for remediation of soil contamination with polycyclic aromatic hydrocarbons (PAHs),ubiquitous persistent environmental pollutants derived from natural and anthropogenic processes,in the last decade.In this study,a pot experiment was conducted to investigate the potential of phytoremediation of pyrcne from spiked soils planted with white clover (Trifolium repens) in the greenhouse with a series of pyrene concentrations ranging from 4.22 to 365.38 mg kg-1.The results showed that growth of white clover on pyrenecontaminated soils was not affected.The removal of pyrene from the spiked soils planted with white clover was obviously higher than that from the unplanted soils.At the end of the experiment (60 d),the average removal ratio of pyrene in the spiked soils with white clover was 77%,which was 31% and 57% higher than those of the controls with or without micobes,respeetivcly.Both roots and shoots of white clover took up pyrene from the spiked soils and pyrene uptake increased with the soil pyrene concentration.However,the plant-enhanced dissipation of soil pyrene may be the result of plant-promoted microbial degradation and direct uptake and accumulation of pyrene by white clover were only a small part of the pyrene dissipation.Bioconcentration factors of pyrene (BCFs,ratio of pyrene,on a dry weight basis,in the plant to that in the soil) tended to decrease with increase in the residual soil pyrene concentration.Therefore,removal of pyrene in the contaminated soils was feasible using white clove.

  8. Removal of fluoride contamination in water by three aquatic plants.

    Science.gov (United States)

    Karmakar, Sukalpa; Mukherjee, Joydeep; Mukherjee, Somnath

    2016-01-01

    Phytoremediation, popularly known as 'green technology' has been employed in the present investigation to examine the potential of fluoride removal from water by some aquatic plants. Fluoride contamination in drinking water is very much prevalent in different parts of the world including India. Batch studies were conducted using some aquatic plants e.g., Pistia stratiotes, Eichhornia crassipes, and Spirodela polyrhiza which profusely grow in natural water bodies. The experimental data exhibited that all the above three aquatic floating macrophytes could remove fluoride to some relative degree of efficiency corresponding to initial concentration of fluoride 3, 5, 10, 20 mg/l after 10 days exposure time. Result showed that at lower concentration level i.e., 3 mg/L removal efficiency of Pistia stratiotes (19.87%) and Spirodela polyrhiza (19.23%) was found to be better as compared to Eichhornia crassipes (12.71%). Some of the physiological stress induced parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, total protein, catalase, and peroxidase were also studied to explore relative damage within the cell. A marginal stress was imparted among all the plants for lower concentration values (3 mg/L), whereas at 20 mg/l, maximum damage was observed.

  9. Two-pulse rapid remote surface contamination measurement.

    Energy Technology Data Exchange (ETDEWEB)

    Headrick, Jeffrey M.; Kulp, Thomas J.; Bisson, Scott E.; Reichardt, Thomas A.; Farrow, Roger L.

    2010-11-01

    This project demonstrated the feasibility of a 'pump-probe' optical detection method for standoff sensing of chemicals on surfaces. Such a measurement uses two optical pulses - one to remove the analyte (or a fragment of it) from the surface and the second to sense the removed material. As a particular example, this project targeted photofragmentation laser-induced fluorescence (PF-LIF) to detect of surface deposits of low-volatility chemical warfare agents (LVAs). Feasibility was demonstrated for four agent surrogates on eight realistic surfaces. Its sensitivity was established for measurements on concrete and aluminum. Extrapolations were made to demonstrate relevance to the needs of outside users. Several aspects of the surface PF-LIF physical mechanism were investigated and compared to that of vapor-phase measurements. The use of PF-LIF as a rapid screening tool to 'cue' more specific sensors was recommended. Its sensitivity was compared to that of Raman spectroscopy, which is both a potential 'confirmer' of PF-LIF 'hits' and is also a competing screening technology.

  10. Simultaneous removal of phenanthrene and cadmium from contaminated soils by saponin, a plant-derived biosurfactant.

    Science.gov (United States)

    Song, Saisai; Zhu, Lizhong; Zhou, Wenjun

    2008-12-01

    Batch experiments were conducted to evaluate the performance of saponin, a plant-derived biosurfactant, for simultaneously removing phenanthrene and cadmium from the combined contaminated soils. Results showed that phenanthrene was desorbed from the contaminated soils by saponin with the partition of phenanthrene into surfactant micelle, meanwhile cadmium was effectively removed from the contaminated soils by the complexation of cadmium with the external carboxyl groups of saponin micelle. The efficiencies of saponin for the removal of phenanthrene and cadmium from the contaminated soils were greater than that of Triton X100 and citric acid, respectively. At concentration of 3750 mg/L, saponin has a removal rate of 87.7% and 76.2% of cadmium and phenanthrene, respectively, from the combined contaminated soil. The removals of cadmium and phenanthrene from the soils were not obviously constrained each other. Thus, saponin has the potential for the removal of heavy metal and PAHs from the combined contaminated soils.

  11. Removal Efficiency of Microbial Contaminants from Hospital Wastewaters

    KAUST Repository

    Timraz, Kenda

    2016-02-01

    This study aims to evaluate the removal efficiency of microbial contaminants from two hospitals on-site Wastewater Treatment Plants (WWTPs) in Saudi Arabia. Hospital wastewaters often go untreated in Saudi Arabia as in many devolving countries, where no specific regulations are imposed regarding hospital wastewater treatment. The current guidelines are placed to ensure a safe treated wastewater quality, however, they do not regulate for pathogenic bacteria and emerging contaminants. Results from this study have detected pathogenic bacterial genera and antibiotic resistant bacteria in the sampled hospitals wastewater. And although the treatment process of one of the hospitals was able to meet current quality guidelines, the other hospital treatment process failed to meet these guidelines and disgorge of its wastewater might be cause for concern. In order to estimate the risk to the public health and the impact of discharging the treated effluent to the public sewage, a comprehensive investigation is needed that will facilitate and guide suggestions for more detailed guidelines and monitoring.

  12. Removal of Persistent Organic Contaminants by Electrochemically Activated Sulfate.

    Science.gov (United States)

    Farhat, Ali; Keller, Jurg; Tait, Stephan; Radjenovic, Jelena

    2015-12-15

    Solutions of sulfate have often been used as background electrolytes in the electrochemical degradation of contaminants and have been generally considered inert even when high-oxidation-power anodes such as boron-doped diamond (BDD) were employed. This study examines the role of sulfate by comparing electro-oxidation rates for seven persistent organic contaminants at BDD anodes in sulfate and inert nitrate anolytes. Sulfate yielded electro-oxidation rates 10-15 times higher for all target contaminants compared to the rates of nitrate anolyte. This electrochemical activation of sulfate was also observed at concentrations as low as 1.6 mM, which is relevant for many wastewaters. Electrolysis of diatrizoate in the presence of specific radical quenchers (tert-butanol and methanol) had a similar effect on electro-oxidation rates, illustrating a possible role of the hydroxyl radical ((•)OH) in the anodic formation of sulfate radical (SO4(•-)) species. The addition of 0.55 mM persulfate increased the electro-oxidation rate of diatrizoate in nitrate from 0.94 to 9.97 h(-1), suggesting a nonradical activation of persulfate. Overall findings indicate the formation of strong sulfate-derived oxidant species at BDD anodes when polarized at high potentials. This may have positive implications in the electro-oxidation of wastewaters containing sulfate. For example, the energy required for the 10-fold removal of diatrizoate was decreased from 45.6 to 2.44 kWh m(-3) by switching from nitrate to sulfate anolyte.

  13. Activated soil filters for removal of biocides from contaminated run-off and waste-waters.

    Science.gov (United States)

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael; Janzen, Niklas; Niederstrasser, Bernd; Scheytt, Traugott

    2011-11-01

    Building facades can be equipped with biocides to prevent formation of algal, fungal and bacterial films. Thus run-off waters may contain these highly active compounds. In this study, the removal of several groups of biocides from contaminated waters by means of an activated soil filter was studied. A technical scale activated vertical soil filter (biofilter) with different layers (peat, sand and gravel), was planted with reed (Phragmites australis) and used to study the removal rates and fate of hydrophilic to moderate hydrophobic (log K(ow) 1.8-4.4) biocides and biocide metabolites such as: Terbutryn, Cybutryn (Irgarol® 1051), Descyclopropyl-Cybutryn (Cybutryn and Terbutryn metabolite), Isoproturon, Diuron, and its metabolite Diuron-desmonomethyl, Benzo-isothiazolinone, n-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone and Iodocarbamate (Iodocarb). Three experiments were performed: the first one (36 d) under low flow conditions (61 L m(-2) d(-1)) reached removal rates between 82% and 100%. The second one was performed to study high flow conditions: During this experiment, water was added as a pulse to the filter system with a hydraulic load of 255 L m(-2) within 5 min (retention time waters or infiltration into soil without appropriate removal. In the last experiment the removal efficiencies of the different layers were studied. Though the peat layer was responsible for most of the removal, the sand and gravel layers also contributed significantly for some compounds. All compounds are rather removed by degradation than by sorption. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Boron contamination in drinking - irrigation water and boron removal methods

    Directory of Open Access Journals (Sweden)

    Meltem Bilici Başkan

    2014-03-01

    Full Text Available Boron presents in IIIA group of periodic table and has high ionization capacity. Therefore it is classified as a metalloid. Average boron concentration in earth's crust is 10 mg/kg. It presents in the environment as a salts of Ca, Na, and Mg. Boron reserves having high concentration and economical extent are found mostly in Turkey and in arid, volcanic and high hydrothermal activity regions of U.S. as compounds of boron attached to oxygen. Boron is an essential micronutrient for plants, although it may be toxic at higher levels. The range in which it is converted from a nutrient to a contaminant is quite narrow. Boron presents in water environment as a boric acid and rarely borate salts. The main boron sources, whose presence is detected in surface waters, are urban wastes and industrial wastes, which can come from a wide range of different activities as well as several chemical products used in agriculture. In Turkey, the most pollutant toxic element in drinking and irrigation water is boron. Therefore boron removal is very important in terms of human health and agricultural products in high quality. Mainly boron removal methods from drinking water and irrigation water are ion exchange, ultrafiltration, reverse osmosis, and adsorption.

  15. Experimental Study of SO2 Removal by Pulsed DBD Along with the Application of Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    RONG Ming-zhe; LIU Ding-xin; WANG Xiao-hua; WANG Jun-hua

    2007-01-01

    Dielectric barrier discharge (DBD) for SO2 removal from indoor air is investigated.In order to improve the removal efficiency,two novel methods are combined in this paper,namely by applying a pulsed driving voltage with nanosecond rising time and applying a magnetic field.For SO2 removal efficiency,different matches of electric field and magnetic field are discussed.And nanosecond rising edge pulsed power supply and microsecond rising edge pulsed power supply are compared.It can be concluded that a pulsed DBD with nanosecond rising edge should be adopted,and electrical field and magnetic field should be applied in an appropriate match.

  16. Effects of vegetations on the removal of contaminants in aquatic environments:A review

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; ZHENG Sha-sha; WANG Pei-fang; QIAN Jin

    2014-01-01

    This paper reviews the removal of contaminants including nutrients, metals and organic pollutants by vegetations in aquatic environments. The removal efficiencies are considered with respect to 16, 19 and 14 kinds of different aquatic plants, respectively in three tables. Due to different characteristics, the removal effects of plants on contaminants from the overlying water differ greatly. The vegetation can improve the water quality mainly through two ways: (1) to adsorb and absorb pollutants from water, (2) to prevent pollutants from releasing from sediment. The contaminant removal mechanisms of vegetations and related physical, chemical and biological effects are discussed. The effects of vegetations on the contaminant removal are found to depend on the environmental conditions, the number and the type of plants, the nature and the chemical structure of the pollutants. In addition, the contaminant release and removal by vegetations under hydrodynamic conditions is specially addressed. Further research directions are suggested.

  17. Restoring contaminated wires, removing gas contaminants, and aging studies of drift tube chambers

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Thomas E-mail: marshall@fnal.gov

    2003-12-01

    The original muon detection system of the Fermilab D0 colliding beam experiment contained 12,000 drift cells 10 cmx5 cm in cross-section and up to 580 cm in length. The gas mixture used was Ar/CF{sub 4}/CO{sub 2} (90:6:4). There was one recycling gas system for all the chambers. During the first year of operation, it was discovered that inefficient cells, all in regions of high radiation, had a contaminating shell of crud coating their wires. The source of the contaminant was outgassing of the cathode pads, which were made from a laminate of fiberglass and epoxy/polyester resin, with a copper cladding on one surface. The vapor formed a brittle sheath on the wires, but only in regions of high current discharge due to radiation from the accelerator and colliding beams. A method for cleaning wires in place was devised. By heating the wire quickly to a temperature close to the melting temperature of gold, the sheath was ripped to shreds and blown away. The procedure for 'zapping' wires and for removing the contaminating vapor is presented. The upgraded D0 experiment now uses Iarocci-type mini-drift tubes for the forward muon system. The results of aging tests for these chambers are also presented.

  18. Chemical coagulation-based processes for trace organic contaminant removal: current state and future potential.

    Science.gov (United States)

    Alexander, Jonathan T; Hai, Faisal I; Al-Aboud, Turki M

    2012-11-30

    Trace organic contaminants have become an increasing cause of concern for governments and water authorities as they attempt to respond to the potential challenges posed by climate change by implementing sustainable water cycle management practices. The augmentation of potable water supplies through indirect potable water reuse is one such method currently being employed. Given the uncertainty surrounding the potential human health impacts of prolonged ingestion of trace organic contaminants, it is vital that effective and sustainable treatment methods are utilized. The purpose of this article is to provide a comprehensive literature review of the performance of the chemical coagulation process in removing trace organic contaminants from water. This study evaluated the removal data collated from recent research relating to various trace organic contaminants during the coagulation process. It was observed that there is limited research data relating to the removal of trace organic contaminants using coagulation. The findings of this study suggest that there is a gap in the current research investigating the potential of new types of coagulants and exploring coagulation-based hybrid processes to remove trace organic contaminants from water. The data analysed in this study regarding removal efficiency suggests that, even for the significantly hydrophobic compounds, hydrophobicity is not the sole factor governing removal of trace organic contaminants by coagulation. This has important implications in that the usual practice of screening coagulants based on turbidity (suspended solid) removal proves inadequate in the case of trace organic contaminant removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Solvent cleaning system and method for removing contaminants from solvent used in resin recycling

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2009-01-06

    A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

  20. 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.

  1. Influence of the pulse duration and the experimental approach onto the specific removal rate for ultra-short pulses

    Science.gov (United States)

    Jaeggi, B.; Neuenschwander, B.; Remund, S.; Kramer, T.

    2017-02-01

    To be competitive in industrial applications the throughput is a key factor in laser micro machining using ultra-short pulsed laser systems. Both, ps and fs laser systems are suitable for industrial applications. Therefore one has to choose the right pulse duration for highest ablation efficiency. As shown in earlier publications the efficiency of the ablation process can be described by the specific removal rate, which has a maximum value at an optimum fluence. But its value often bases on a calculation using the threshold fluence and energy penetration depth deduced by measuring the depth of ablated cavities machined with different fluences and number of pulses. But this calculated specific removal rate often differs from the one deduced from ablated squares as recently shown in literature. Further an unexpected drop of the specific removal rate was reported for stainless steel when the pulse duration was reduced from 900 fs to 400 fs. Thus the influence of the pulse duration in the fs and low ps regime onto the specific removal rate is investigated with different methods for industrial relevant materials

  2. Evidence based decontamination protocols for the removal of external Δ9-tetrahydrocannabinol (THC) from contaminated hair.

    Science.gov (United States)

    Duvivier, Wilco F; Peeters, Ruth J P; van Beek, Teris A; Nielen, Michel W F

    2016-02-01

    External contamination can cause false positive results in forensic hair testing for drugs of abuse and is therefore a major concern when hair evidence is used in court. Current literature about decontamination strategies is mainly focused on external cocaine contamination and no consensus on the best decontamination procedure for hair samples containing cannabinoids has been reached so far. In this study, different protocols with solvents, both organic as well as aqueous, were tested on blank and drug user hair for their performance on removing external cannabis contamination originating from either smoke or indirect contact with cannabis plant material. Smoke contamination was mimicked by exposing hair samples to smoke from a cannabis cigarette and indirect contact contamination by handling hair with cannabis contaminated gloves or hands. Δ9-tetrahydrocannabinol (THC) levels in the hair samples and wash solvents were determined using liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Aqueous surfactant solutions removed more THC contamination compared to water, but much less than organic solvents. Methanol, dichloromethane and chloroform were most efficient in removing THC contamination. Due to its lower environmental impact, methanol was chosen as the preferred decontamination solvent. After testing of different sequential wash steps on externally contaminated blank hair, three protocols performed equally well, removing all normal level and more than 99% of unrealistically high levels of external cannabis contamination. Thorough testing on cannabis users' hair, both as such and after deliberate contamination, showed that using these protocols all contamination could be washed from the hair while no incorporated THC was removed from truly positive samples. The present study provides detailed scientific evidence in support of the recommendations of the Society of Hair Testing: a protocol using a single methanol wash followed by a single aqueous

  3. Selective removal of composite sealants with near-ultraviolet laser pulses of nanosecond duration.

    Science.gov (United States)

    Louie, Tiffany M; Jones, Robert S; Sarma, Anupama V; Fried, Daniel

    2005-01-01

    It is often necessary to replace pit and fissure sealants and composite restorations. This task is complicated by the necessity for complete removal of the remaining composite to enable suitable adhesion of new composite. Previous studies have shown that 355-nm laser pulses from a frequency-tripled Nd:YAG laser can selectively remove residual composite after orthodontic bracket removal on enamel surfaces. Our objective is to determine if such laser pulses are suitable for selective removal of composite pit and fissure sealants and restorations. Optical coherence tomography is used to acquire optical cross sections of the occlusal topography nondestructively before sealant application, after sealant application, and after sealant removal. Thermocouples are used to monitor the temperature in the pulp chamber during composite removal under clinically relevant ablation rates, i.e., 30 Hz and 30 mJ/pulse. At an irradiation intensity of 1.3 J/cm2, pit and fissure sealants are completely removed without visible damage to the underlying enamel. At intensities above 1.5 J/cm2, incident laser pulses remove the resin layer while at the same time preferentially etching the surface of the enamel. Temperature excursions in the pulp chamber of extracted teeth are limited to less than 5 degrees C if air-cooling is used during the rapid removal (1 to 2 min) of sealants, water-cooling is not necessary. Selective removal of composite restorative materials is possible without damage to the underlying sound tooth structure.

  4. Determination of biological removal of recalcitrant organic contaminants in coal gasification waste water.

    Science.gov (United States)

    Ji, Qinhong; Tabassum, Salma; Yu, Guangxin; Chu, Chunfeng; Zhang, Zhenjia

    2015-01-01

    Coal gasification waste water treatment needed a sustainable and affordable plan to eliminate the organic contaminants in order to lower the potential environmental and human health risk. In this paper, a laboratory-scale anaerobic-aerobic intermittent system carried out 66 operational cycles together for the treatment of coal gasification waste water and the removal capacity of each organic pollutant. Contaminants included phenols, carboxylic acids, long-chain hydrocarbons, and heterocyclic compounds, wherein the relative content of phenol is up to 57.86%. The long-term removal of 77 organic contaminants was evaluated at different hydraulic retention time (anaerobic24 h + aerobic48 h and anaerobic48 h +aerobic48 h). Contaminant removal ranged from no measurable removal to near-complete removal with effluent concentrations below the detection limit. Contaminant removals followed one of four trends: steady-state removal throughout, increasing removal to steady state (acclimation), decreasing removal, and no removal. Organic degradation and transformation in the reaction were analysed by gas chromatography/mass spectrometry technology.

  5. A multi-process phytoremediation system for removal of polycyclic aromatic hydrocarbons from contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Huang Xiaodong; El-Alawi, Yousef; Penrose, Donna M.; Glick, Bernard R.; Greenberg, Bruce M

    2004-08-01

    To improve phytoremediation processes, multiple techniques that comprise different aspects of contaminant removal from soils have been combined. Using creosote as a test contaminant, a multi-process phytoremediation system composed of physical (volatilization), photochemical (photooxidation) and microbial remediation, and phytoremediation (plant-assisted remediation) processes was developed. The techniques applied to realize these processes were land-farming (aeration and light exposure), introduction of contaminant degrading bacteria, plant growth promoting rhizobacteria (PGPR), and plant growth of contaminant-tolerant tall fescue (Festuca arundinacea). Over a 4-month period, the average efficiency of removal of 16 priority PAHs by the multi-process remediation system was twice that of land-farming, 50% more than bioremediation alone, and 45% more than phytoremediation by itself. Importantly, the multi-process system was capable of removing most of the highly hydrophobic, soil-bound PAHs from soil. The key elements for successful phytoremediation were the use of plant species that have the ability to proliferate in the presence of high levels of contaminants and strains of PGPR that increase plant tolerance to contaminants and accelerate plant growth in heavily contaminated soils. The synergistic use of these approaches resulted in rapid and massive biomass accumulation of plant tissue in contaminated soil, putatively providing more active metabolic processes, leading to more rapid and more complete removal of PAHs. - Persistent PAH contaminants in soils can be removed more completely and rapidly by using multiple remediation processes.

  6. Simultaneous removal of phenanthrene and cadmium from contaminated soils by saponin, a plant-derived biosurfactant

    Energy Technology Data Exchange (ETDEWEB)

    Song Saisai [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Zhu Lizhong [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China)], E-mail: zlz@zju.edu.cn; Zhou Wenjun [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China)

    2008-12-15

    Batch experiments were conducted to evaluate the performance of saponin, a plant-derived biosurfactant, for simultaneously removing phenanthrene and cadmium from the combined contaminated soils. Results showed that phenanthrene was desorbed from the contaminated soils by saponin with the partition of phenanthrene into surfactant micelle, meanwhile cadmium was effectively removed from the contaminated soils by the complexation of cadmium with the external carboxyl groups of saponin micelle. The efficiencies of saponin for the removal of phenanthrene and cadmium from the contaminated soils were greater than that of Triton X100 and citric acid, respectively. At concentration of 3750 mg/L, saponin has a removal rate of 87.7% and 76.2% of cadmium and phenanthrene, respectively, from the combined contaminated soil. The removals of cadmium and phenanthrene from the soils were not obviously constrained each other. Thus, saponin has the potential for the removal of heavy metal and PAHs from the combined contaminated soils. - Saponin has great potential for the simultaneous removal of cadmium and phenanthrene from the combined contaminated soils.

  7. Arsenic Removal from Water by Adsorption on Iron-Contaminated Cryptocrystalline Graphite

    Science.gov (United States)

    Yang, Qiang; Yang, Lang; Song, Shaoxian; Xia, Ling

    This work aimed to study the feasibility of using iron-contaminated graphite as an adsorbent for As(V) removal from water. The adsorbent was prepared by grinding graphite concentrate with steel ball. The study was performed through the measurements of adsorption capacity, BET surface area and XPS analysis. The experimental results showed that the iron-contaminated graphite exhibited significantly high adsorption capacity of As(V). The higher the iron contaminated on the graphite surface, the higher the adsorption capacity of As(V) on the material obtained. It was suggested that the ion-contaminated graphite was a good adsorbent for As(V) removal.

  8. The effects of small dam removal on the distribution of sedimentary contaminants.

    Science.gov (United States)

    Ashley, Jeffrey T F; Bushaw-Newton, Karen; Wilhelm, Matt; Boettner, Adam; Drames, Gregg; Velinsky, David J

    2006-03-01

    With increasing concern over degradation of aquatic resources, issues of liability, and maintenance costs, removal of small dams has become increasing popular. Although the benefits of removal seem to outweigh the drawbacks, there is a relative paucity of studies documenting the extent and magnitude of biological and chemical changes associated with dam removal, especially those evaluating potential changes in contaminant inventories. In August and November of 2000, a run-of-the-river dam on Manatawny Creek (southeast Pennsylvania) was removed in a two-stage process. To assess the effects of dam removal on the contaminant redistribution within the creek, sedimentary concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and trace metals (Cd, Cr, Cu, Ni, Pb, Zn) were evaluated prior to and several months after removal. Pre- and post-removal analyses revealed elevated and spatially variable concentrations of total PAHs (ranging from approximately 200 to 81,000 ng(g dry weight) and low to moderate concentrations of trace metals and PCBs. The concentrations of these sedimentary contaminants pre- versus post-removal were not significantly different. Additionally, though the impoundment received storm water run-off and associated contaminants from the adjacent city of Pottstown, the total inventory of fine-grain sediments in the impoundment prior to removal was very low. The removal of the low-level Manatawny Creek dam did not significantly redistribute contaminants downstream. However, each dam removal should be assessed on a case by case basis where the potential of sedimentary contaminant redistribution upon dam removal exists.

  9. Effects of electrocardiography contamination and comparison of ECG removal methods on upper trapezius electromyography recordings.

    Science.gov (United States)

    Marker, Ryan J; Maluf, Katrina S

    2014-12-01

    Electromyography (EMG) recordings from the trapezius are often contaminated by the electrocardiography (ECG) signal, making it difficult to distinguish low-level muscle activity from muscular rest. This study investigates the influence of ECG contamination on EMG amplitude and frequency estimations in the upper trapezius during muscular rest and low-level contractions. A new method of ECG contamination removal, filtered template subtraction (FTS), is described and compared to 30 Hz high-pass filter (HPF) and averaged template subtraction (ATS) methods. FTS creates a unique template of each ECG artifact using a low-pass filtered copy of the contaminated signal, which is subtracted from contaminated periods in the original signal. ECG contamination results in an over-estimation of EMG amplitude during rest in the upper trapezius, with negligible effects on amplitude and frequency estimations during low-intensity isometric contractions. FTS and HPF successfully removed ECG contamination from periods of muscular rest, yet introduced errors during muscle contraction. Conversely, ATS failed to fully remove ECG contamination during muscular rest, yet did not introduce errors during muscle contraction. The relative advantages and disadvantages of different ECG contamination removal methods should be considered in the context of the specific motor tasks that require analysis.

  10. Growth and Contaminant Removal Effect of Several Plants in Constructed Wetlands

    Institute of Scientific and Technical Information of China (English)

    Xiu-Yun Cheng; Ming-Qiu Liang; Wen-Yin Chen; Xu-Cheng Liu; Zhang-He Chen

    2009-01-01

    The aim of the present study is to probe the relation between plant growth and its decontamination effect in constructed wetlands.Four species were studied in the small-scale mono-cuitured constructed wetlands, which were fed with domestic wastewater. Plant growth indexes were correlated with contaminant removal performance of the constructed wetlands. Wetlands planted with Cyperus flabelliformis Rottb. showed the highest growth indexes such as shoot growth, biomass, root activity, root biomass increment, and the highest contaminant removal rates, whereas wetlands planted with Vetiveria zizanioides L. Nash had the lowest growth indexes and the lowest removal rates. Above-ground biomass and total biomass were significantly correlated with ammonia nitrogen removal, and below-ground biomass with soluble reactive phosphorus removal. Photosynthetic rate had higher correlation with nitrogen removal in these species. Root activity and root biomass increment was more correlated with 5 d biochemical oxygen demand removal.Chemical oxygen demand removal had lower correlations with plant growth indexes. All four species had higher removal rates in summer and autumn. The results suggest that the effect of plant growth on contaminant removal in constructed wetlands were different specifically in plants and contaminants.

  11. Cell membrane electropermeabilization by symmetrical bipolar rectangular pulses. Part II. Reduced electrolytic contamination.

    Science.gov (United States)

    Kotnik, T; Miklavcic, D; Mir, L M

    2001-08-01

    The paper presents a comparative study of the contamination of a cell suspension by ions released from aluminum cuvettes (Al(3+)) and stainless steel electrodes (Fe(2+)/Fe(3+)) during cell membrane electropermeabilization by unipolar and by symmetrical bipolar rectangular electric pulses. A single pulse and a train of eight pulses were delivered to electrodes at a 2-mm distance, with 100-micros and 1-ms pulse durations, and amplitudes ranging from 0 to 400 V for unipolar, and from 0 to 280 V for bipolar pulses. We found that the released concentrations of Al(3+) and Fe(2+)/Fe(3+) were always more than one order of magnitude lower with bipolar pulses than with unipolar pulses of the same amplitude and duration. We then investigated the viability of DC-3F cells after 1 h of incubation in the medium containing different concentrations of Al(3+) or Fe(2+)/Fe(3+) within the range of measured released concentrations (up to 2.5 mM for both ions), thus separating the effects of electrolytic contamination from the effects of electropermeabilization itself. For Fe(2+)/Fe(3+), loss of cell viability became significant at concentrations above 1.5 mM, while for Al(3+), no effect on cell survival was detected within the investigated range. Still, reports on the biochemical effects of released Al(3+) also suggest that with aluminum cuvettes, electrolytic contamination can be detrimental. Our study shows that electrolytic contamination and its detrimental effects can be largely reduced with no loss in efficiency of electropermeabilization, if bipolar rectangular pulses of the same amplitude and duration are used instead of the commonly applied unipolar pulses.

  12. Contaminant sampling to facilitate dam removals/habitat restoration in New England

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In a screening level survey of sediments impounded by New England dams that were being investigated for possible removal, only one of nine sites had contaminant...

  13. Microbial contamination of removable dental prosthesis at different interval of usage: An in vitro study

    Directory of Open Access Journals (Sweden)

    Vijita Vijay Nair

    2016-01-01

    Conclusion: There is a linear increase in microbial contamination of removable dental prosthesis as the duration of usage increases and might increase the susceptibility of individuals' to many diseases.

  14. A method for removal of CO from exhaust gas using pulsed corona discharge.

    Science.gov (United States)

    Li, X; Yang, L; Lei, Y; Wang, J; Lu, Y

    2000-10-01

    An experimental study of the oxidation of CO in exhaust gas from a motorcycle has been carried out using plasma chemical reactions in a pulsed corona discharge. In the process, some main parameters, such as the initial CO concentration, amplitude and frequency of pulses, residence time, reactor volume, and relative humidity (RH), as well as their effects on CO removal characteristics, were investigated. O3, which is beneficial to reducing CO, was produced during CO removal. When the exhaust gas was at ambient temperature, more than 80% CO removal efficiency was realized at an initial concentration of 288 ppm in a suitable range of the parameters.

  15. Photochemical removal of organic contaminants from silicon surface at room temperature

    Science.gov (United States)

    Fominski, V. Yu.; Naoumenko, O. I.; Nevolin, V. N.; Alekhin, A. P.; Markeev, A. M.; Vyukov, L. A.

    1996-04-01

    Using in situ x-ray photoelectron spectroscopy we have investigated the possibility of photochemical organic contaminant removal from a silicon surface at room temperature in oxygen and fluorine containing atmospheres (O2, NF3/H2, O2/NF3/H2). In contrast to UV irradiation in O2 and NF3/H2 reagents, the possibility of complete organic contaminant removal has been observed in O2/NF3/H2 gas mixture.

  16. Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents

    Science.gov (United States)

    Jasper, Justin T.; Nguyen, Mi T.; Jones, Zackary L.; Ismail, Niveen S.; Sedlak, David L.; Sharp, Jonathan O.; Luthy, Richard G.; Horne, Alex J.; Nelson, Kara L.

    2013-01-01

    Abstract Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe. PMID:23983451

  17. Evaluation of pulsed corona discharge plasma for the treatment of petroleum-contaminated soil.

    Science.gov (United States)

    Li, Rui; Liu, Yanan; Mu, Ruiwen; Cheng, Wenyan; Ognier, Stéphanie

    2017-01-01

    Petroleum hydrocarbons released to the environment caused by leakage or illegal dumping pose a threat to human health and the natural environment. In this study, the potential of a pulsed corona discharge plasma system for treating petroleum-polluted soils was evaluated. This system removed 76.93 % of the petroleum from the soil in 60 min with an energy efficiency of 0.20 mg/kJ. Furthermore, the energy and degradation efficiencies for the remediation of soil contaminated by single polyaromatic hydrocarbons, such as phenanthrene and pyrene, were also compared, and the results showed that this technology had potential in organic-polluted soil remediation. In addition, the role of water molecules was investigated for their direct involvement in the formation and transportation of active species. The increase of soil moisture to a certain extent clearly benefitted degradation efficiency. Then, treated soils were analyzed by FTIR and GC-MS for proposing the degradation mechanism of petroleum. During the plasma discharging processes, the change of functional group and the detection of small aromatic hydrocarbons indicated that the plasma active species attached petroleum hydrocarbons and degradation occurred. This technique reported herein demonstrated significant potential for the remediation of heavily petroleum-polluted soil, as well as for the treatment of organic-polluted soils.

  18. Evaluation of the Effect of Silicone Contamination on Various Bond Systems and the Feasibility of Removing the Contamination

    Science.gov (United States)

    Stanley, Stephanie D.

    2008-01-01

    Silicone is a contaminant that can cause catastrophic failure of a bond system depending on the materials and processes used to fabricate the bond system, Unfortunately, more and more materials are fabricated using silicone. The purpose of this testing was to evaluate which bond systems are sensitive to silicone contamination and whether or not a cleaning process could be utilized to remove the silicone to bring the bond system performance back to baseline. Due to the extensive nature of the testing attempts will be made to generalize the understanding within classes of substrates, bond systems, and surface preparation and cleaning methods. This study was done by contaminating various meta! (steel, inconel, and aluminum), phenolic (carbon cloth phenolic and glass cloth phenolic), and rubber (natural rubber, asbestos-silicone dioxide filled natural butyldiene rubber, silica-filled ethylene propylenediene monomer, and carbon-filled ethylene propylenediene monomer) substrates which were then bonded using various adhesives and coatings (epoxy-based adhesives, paints, ablative compounds, and Chemlok adhesives) to determine the effect silicone contamination has on a given bond system's performance. The test configurations depended on the bond system being evaluated. The study also evaluated the feasibility of removing the silicone contamination by cleaning the contaminated substrate prior to bonding. The cleaning processes also varied depending on bond system.

  19. Selective removal of composite sealants with near-UV laser pulses

    Science.gov (United States)

    Louie, Tiffany M.; Jones, Robert S.; Sarma, Anupama V.; Fried, Daniel

    2004-05-01

    It is often necessary to replace pit and fissure sealants and composite restorations. This task is complicated by the necessity for complete removal of the remaining composite to enable suitable adhesion of new composite. Previous studies have shown that lasers pulses from a frequency-tripled Nd:YAG laser (355-nm) can selectively remove residual composite after orthodontic bracket removal on enamel surfaces. UV laser light is preferentially absorbed by polymeric resins and the organic content of the tooth enamel. The objective of this study was to determine if such laser pulses are suitable for selective removal of the old composite from pit and fissure sealants and restorations without damaging surrounding sound tissues. Optical coherence tomography was used to acquire optical cross sections of the occlusal topography and peripheral tooth structure non-destructively before application of the sealants, after sealant application, and after sealant removal with 355-nm laser pulses with intensities ranging from 0-10 J/cm2. Thermocouples were used to monitor the temperature in the pulp chamber during composite removal under clinically relevant ablation rates, i.e., 30 Hz and 30 mJ per laser pulse. At an irradiation intensity of 1.3 J/cm2 pit and fissure sealants were completely removed without visible damage to the underlying enamel. At intensities above 1.5 J/cm2, the laser removes the resin layer while at the same time preferentially etching the surface of the enamel. Temperature excursions in the pulp chamber of extracted teeth was limited to less than 5°C if air-cooling was used during the rapid removal (1-2 min) of sealants, water-cooling was not needed. This is the first presentation of a method for the selective removal of composite restorative materials without damage to the underlying sound tooth structure.

  20. Removal of emerging contaminants in sewage water subjected to advanced oxidation with ozone.

    Science.gov (United States)

    Ibáñez, M; Gracia-Lor, E; Bijlsma, L; Morales, E; Pastor, L; Hernández, F

    2013-09-15

    Advanced oxidation processes (AOP) based on ozone treatments, assisted by ultrasounds, have been investigated at a pilot-plant scale in order to evaluate the removal of emerging contaminants in sewage water. Around 60 emerging contaminants, mainly pharmaceuticals from different therapeutically classes and drugs of abuse, have been determined in urban wastewater samples (treated and untreated) by LC-MS/MS. In a first step, the removal efficiency of these contaminants in conventional sewage water treatment plants was evaluated. Our results indicate that most of the compounds were totally or partially removed during the treatment process of influent wastewater. Up to 30 contaminants were quantified in the influent and effluent samples analysed, being antibiotics, anti-inflammatories, cholesterol lowering statin drugs and angiotensin II receptor antagonists the most frequently detected. Regarding drugs of abuse, cocaine and its metabolite benzoylecgonine were the most frequent. In a second step, the effectiveness of AOP in the removal of emerging contaminants remaining in the effluent was evaluated. Ozone treatments have been proven to be highly efficient in the removal, notably decreasing the concentrations for most of the emerging contaminants present in the water samples. The use of ultrasounds, alone or assisting ozone treatments, has been shown less effective, being practically unnecessary.

  1. Phytoremediation mechanisms for polycyclic aromatic hydrocarbons removing from contaminated soils

    Directory of Open Access Journals (Sweden)

    Alagić Slađana Č.

    2015-01-01

    Full Text Available Phytoremediation of polycyclic aromatic hydrocarbons (PAHs from soil aims to degrade them into less toxic/non toxic compounds and limit their further movement by sequestration and accumulation into the vacuoles. Lipophilic organic compounds such as PAHs are bound strongly to the epidermis of the root tissue and are rarely translocated within plant. There are no reports in the literature data of PAHs being completely mineralized by plants. There is little evidence to suggest that PAHs accumulate to significant degree in plants, but there still is a lot of evidences on the ability of various plant species (most often grasses and legumes, to degrade and dissipate these dangerous contaminants. The primary mechanism controlling the dissipation of PAHs is rhizosphere microbial degradation where microbes use PAHs molecules as carbon substrates for growth, which in final, leads to the breakdown or total mineralization of the contaminants. The process is usually augmented by the excretion of root exudates (e.g., sugars, alcohols, acids, enzymes, and the build-up of organic carbon in the soil, so the proper selection of particular plant species represents a critical management decision for PAHs phytoremediation. These facts favor the rhyzoremediation as the best solution for sites contaminated with PAHs.

  2. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Secondes, Mona Freda N. [Environmental Engineering Graduate Program, Department of Chemical Engineering, University of the Philippines – Diliman, Quezon City (Philippines); Naddeo, Vincenzo, E-mail: vnaddeo@unisa.it [Sanitary and Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, Fisciano 84084 (Saudi Arabia) (Italy); Belgiorno, Vincenzo [Sanitary and Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, Fisciano 84084 (Saudi Arabia) (Italy); Ballesteros, Florencio [Environmental Engineering Graduate Program, Department of Chemical Engineering, University of the Philippines – Diliman, Quezon City (Philippines)

    2014-01-15

    Highlights: • Above 99% of the emerging contaminants were removed in the USAMe process. • Influence of PAC dose and US frequency on removal is studied. • Improved performance is due to PAC adsorption enhancement and sonolytic degradation. • US irradiation improved efficiency and delayed declines in the removal of contaminants. • Performance of the hybrid process is better under lower frequency ultrasound irradiation. -- Abstract: Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs.

  3. Chlorobenzene removal efficiencies and removal processes in a pilot-scale constructed wetland treating contaminated groundwater

    DEFF Research Database (Denmark)

    Braeckevelt, M.; Reiche, N.; Trapp, Stefan

    2011-01-01

    Low-chlorinated benzenes (CBs) are widespread groundwater contaminants and often threaten to contaminate surface waters. Constructed wetlands (CWs) in river floodplains are a promising technology for protecting sensitive surface water bodies from the impact of CBs. The efficiency and seasonal var...

  4. [The pulsed water jet for selective removal of bone cement during revision arthroplasty].

    Science.gov (United States)

    Honl, Matthias; Schwieger, Karsten; Carrero, Volker; Rentzsch, Reemt; Dierk, Oliver; Dries, Sebastian; Pude, Frank; Bluhm, Andrea; Hille, Ekkehard; Louis, Hartmut; Morlock, Michael

    2003-10-01

    Conventional tools used in prosthetic revision surgery have a limited range of action within the narrow cement mantle. Water jet cutting technology permits tiny and precisely controlled cuts, and may therefore be an alternative method of bone cement removal. Our study compares the cutting performance on bone cement (PMMA) and bone of a pulsed water jet and a continuous water jet. The aim of the study was to establish whether selective removal of PMMA is possible. 55 bone specimens (bovine femora) and 32 specimens of PMMA were cut with a continuous and a pulsed water jet at different pressures (40 MPa, 60 MPa) and pulse frequencies (0Hz, 50Hz, 250Hz). To ensure comparability of the results, the depths of cut were related to the hydraulic power of that part of the jet actually impinging on the material. While for PMMA the power-related depth of cut increased significantly with the pulse frequency, this did not apply to bone. The cuts produced in bone were sharp-edged. Since PMMA is more brittle than bone, the water jet caused cracks that enlarged further until particles of bone broke away. Although selective removal of PMMA without doing damage to the bone was not possible at the investigated settings of the jet parameters, the results do show that a pulsed water jet can cut bone cement much more effectively than bone. This is an important advantage over conventional non-selective tools for the removal of bone cement.

  5. Experimental research of pulsed discharge plasma and TiO2/Zeolite coupling technology for formaldehyde removal

    Science.gov (United States)

    Dong, Bingyan; Lan, Shuirong

    2013-03-01

    The pulsed discharge plasma combining with catalyst to remove formaldehyde is a novel type of advanced oxidation technology. In the present work, taking wire-tube pulsed discharge plasma and TiO2/Zeolite coupling technology for formaldehyde removal. The studies have investigated the wire-tube reactor with zeolite, TiO2, TiO2/Zeolite for formaldehyde removal respectively. Results show that in the optimal experimental conditions and the baking time is 120 min, the baking temperature is 450 °C, that TiO2/Zeolite catalyst which made by sol-gel shows higher photocatalytic activity and efficiency. The pulsed discharge with TiO2/Zeolite catalyst for formaldehyde removal has higher removal efficiency than pulsed discharge with zeolite or TiO2. Therefore, pulsed discharge plasma with TiO2/Zeolite for the removal of formaldehyde can greatly increase the removal efficiency.

  6. Fast identification and removal of sequence contamination from genomic and metagenomic datasets.

    Directory of Open Access Journals (Sweden)

    Robert Schmieder

    Full Text Available High-throughput sequencing technologies have strongly impacted microbiology, providing a rapid and cost-effective way of generating draft genomes and exploring microbial diversity. However, sequences obtained from impure nucleic acid preparations may contain DNA from sources other than the sample. Those sequence contaminations are a serious concern to the quality of the data used for downstream analysis, causing misassembly of sequence contigs and erroneous conclusions. Therefore, the removal of sequence contaminants is a necessary and required step for all sequencing projects. We developed DeconSeq, a robust framework for the rapid, automated identification and removal of sequence contamination in longer-read datasets (150 bp mean read length. DeconSeq is publicly available as standalone and web-based versions. The results can be exported for subsequent analysis, and the databases used for the web-based version are automatically updated on a regular basis. DeconSeq categorizes possible contamination sequences, eliminates redundant hits with higher similarity to non-contaminant genomes, and provides graphical visualizations of the alignment results and classifications. Using DeconSeq, we conducted an analysis of possible human DNA contamination in 202 previously published microbial and viral metagenomes and found possible contamination in 145 (72% metagenomes with as high as 64% contaminating sequences. This new framework allows scientists to automatically detect and efficiently remove unwanted sequence contamination from their datasets while eliminating critical limitations of current methods. DeconSeq's web interface is simple and user-friendly. The standalone version allows offline analysis and integration into existing data processing pipelines. DeconSeq's results reveal whether the sequencing experiment has succeeded, whether the correct sample was sequenced, and whether the sample contains any sequence contamination from DNA preparation or

  7. Nanosecond pulsed dielectric barrier discharge plasma-catalytic removal of HCHO in humid air

    Science.gov (United States)

    Zhang, Shuai; Wang, Wenchun; Zhang, Li; Zhao, Zilu; Yang, Dezheng

    2017-05-01

    Non-thermal plasma (NTP) has been regarded as a promising method for the removal of a wide range of low concentration volatile organic compounds (VOCs). In this paper, nanosecond pulsed and alternating current dielectric barrier discharge plasmas synergistic catalyst are utilized for removal of formaldehyde (HCHO) in humid air. Working gas is 1% H2O/21% O2/78% N2 with 154 ppm HCHO over total flow rate of 50 mL/min. Specific energy density (SED) are 32.5 JL-1, 35.8 JL-1 and 1069.2 JL-1 at power consumption of 0.325 W, 0.3 W, 8.9 W for removal of 67%, 63.8% and 73.8% HCHO when using bipolar nanosecond pulsed, unipolar nanosecond pulsed and AC dielectric barrier discharge (DBD) plasma, respectively. The removal efficiencies of HCHO using nanosecond pulsed DBD plasma increase approximately 10 20% when the packed-bed Al2O3 pellets exist and can reach up to almost 100% when TiO2 nanoparticles are used while the effect of CeO2 nanoparticles is a bit poor. Analysis indicate that OH radical and O atom play main role for removal HCHO and the gas temperature is a significant factor for its influence on rate constants of HCHO with active particles.

  8. The real contamination of femoral head allografts washed with pulse lavage.

    Science.gov (United States)

    Salmela, P Mikael; Hirn, Martti Y J; Vuento, Risto E

    2002-06-01

    At the Tampere Bone Bank, all the discarded femoral heads from September 1997 to May 2000 were recultured. The grafts had been washed with pulse lavage at harvesting. 48 grafts had been discarded because of a positive culture and 85 with negative cultures because of positive or insufficient serological information. The femoral heads were split into halves, which were recultured as a whole in thioglycolate broth for 14 days. The contamination of previously culture positive and negative femoral heads did not differ. In only 2 cases did we find the same type of bacteria in the primary as in the new culture. Most of the primary contamination proved to be false positive. The real contamination seems to be very low, at least after pulse lavage washing of the femoral head.

  9. A simple technique for removing plant polysaccharide contaminants from DNA.

    Science.gov (United States)

    Do, N; Adams, R P

    1991-02-01

    A survey of the inhibitory effects of various plant polysaccharides on DNA restrictions (HindIII and EcoRI) revealed that neutral polysaccharides (arabino-galactan, dextran, gum guar, gum locust bean, beta-glucan, inulin, laminaran, mannan and starch) were not very inhibitory. In contrast, acidic polysaccharides (carrageenan, dextran sulfate, gum ghatti, gum karaya, pectin and xylan) were very inhibitory, even at low concentrations. The Elutip-d (RPC-5 type resin) was evaluated for removal of the inhibitory polysaccharides. Used alone or in combination with a phenol/chloroform wash, it proved effective in removing the polysaccharide so that HindIII digestion was possible, except in the cases of carrageenan and dextran sulfate. In addition, the genomic DNA extracts from live oak (Quercus virginiana) and magnolia (Magnolia grandiflora) were sufficiently purified so that the DNAs could be restricted with both EcoRI and HindIII.

  10. Application of carbon nanotube technology for removal of contaminants in drinking water: a review.

    Science.gov (United States)

    Upadhyayula, Venkata K K; Deng, Shuguang; Mitchell, Martha C; Smith, Geoffrey B

    2009-12-15

    Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM), and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.

  11. Application of carbon nanotube technology for removal of contaminants in drinking water: A review

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyayula, Venkata K.K., E-mail: vupadhyayula@fairpoint.net [Microbiology and Applied Biochemistry Division, Air Force Research Labs, 139 Barnes Drive, Suite II, Tyndall Air Force Base, Panama City, FL, 32403 (United States); Deng, Shuguang; Mitchell, Martha C. [Chemical Engineering Department, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003 (United States); Smith, Geoffrey B. [Biology Department, New Mexico State University, P.O. Box 30001, MSC 3AF, Las Cruces, NM 88003 (United States)

    2009-12-15

    Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM), and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.

  12. Thermodynamic analysis of the theoretical energy consumption in the removal of organic contaminants by physical methods

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The essential requirements for evaluating the sustainable development of a system and the thermodynamic framework of the energy conservation mechanism in the waste-removal process are proposed.A thermodynamic method of analysis based on the first and second laws of thermodynamics is suggested as a means to analyze the theoretical energy consumption for the removal of organic contaminants by physical methods.Moreover,the theoretical energy consumption for the removal by physical methods of different kinds of representative organic contaminants with different initial concentrations and amounts is investigated at 298.15 K and 1.01325 × 105 Pa.The results show that the waste treatment process has a high energy consumption and that the theoretical energy consumption for the removal of organic contaminants increases with the decrease of their initial concentrations in aqueous solutions.The theoretical energy consumption for the removal of different organic contaminants varies dramatically.Furthermore,the theoretical energy consumption increases greatly with the increase in the amount to be removed.

  13. Removal of emerging contaminants from municipal wastewater with an integrated membrane system, MBR-RO.

    Science.gov (United States)

    Dolar, Davor; Gros, Meritxell; Rodriguez-Mozaz, Sara; Moreno, Jordi; Comas, Joaquim; Rodriguez-Roda, Ignasi; Barceló, Damià

    2012-11-15

    The presence of emerging contaminants in the aquatic environment and their potential effects on living organisms has become an issue of growing concern. Among emerging contaminants, pharmaceuticals may enter the aquatic environment due to their high consumption and their incomplete removal in conventional municipal wastewater treatment plants (WWTPs). The main goal of this study was the assessment of the removal efficiency of pharmaceuticals found in municipal wastewater of a coastal WWTP (Castell-Platja d'Aro, Spain) using an integrated pilot scale membrane system (MBR-RO). Twenty multiple-class pharmaceuticals (including psychiatric drugs, macrolide antibiotics, β-blockers, sulfonamide and fluoroquinolone antibiotics, histamine H2 receptor antagonists, anti-inflammatories, nitroimidazole, β-agonist and antiplatelet agent) were measured in real influent with the lowest average concentration for psychiatric drugs (0.017 μg L(-1)) to the highest for macrolide antibiotics (2.02 μg L(-1)). Although some contaminants were in relatively high concentrations (even up to 2.90 μg L(-1) in the case of ofloxacin). The combination of MBR and RO treatment showed excellent overall removal of target emerging contaminants with removal rates above 99% for all of them. For some compounds (metronidazole, hydrocodone, codein, ranitidine) MBR provided high removal efficiency (up to 95%). Additionally RO membrane showed removal rates always higher than 99%.

  14. Removal of Uranium from Contaminated Water by Clay Ceramics in Flow-Through Columns

    Directory of Open Access Journals (Sweden)

    Charles Florez

    2017-10-01

    Full Text Available Uranium contamination of groundwater increasingly concerns rural residents depending on home wells for their drinking water in communities where uranium is a source of contamination. Established technologies to clean up contaminated aquifers are ineffective in large contaminated areas or are prohibitively expensive. Permeable reactive barriers (PRBs are a low-cost alternative to these methods. In this paper, the applicability of clay ceramic pellets was investigated as permeable reactive barriers (PRBs material for the treatment of uranium-contaminated groundwater. Flow-through columns were fabricated and used to mimic the flow path of a contaminant plume through the reactive media. Experiment results show that clay ceramic pellets effectively remove uranium from uranium-contaminated water and also can be a cost-efficient technique for remediating uranium contaminated groundwater by a clay pellet barrier. Using clay ceramic pellets is also a practical treatment method for uranium removal from drinking water and can supply potable water for households in the affected areas.

  15. Removal of organic contaminants from water or wastewater with liquefied gases

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This study utilized liquefied gases (LG) as extractant to remove various organic contaminants including halogenated hydrocarbons and phenols as well as aromatic compounds from aqueousmatrices. Orthogonal experiments were performed to optimize theoperating conditions such as temperature, co-solvents and so on.Under favorable conditions, high removal efficiencies can bereadily achieved for a great number of representative model organiccontaminants, the removal efficiencies for most of the hydrophobiccontaminants were greater than 90% in a single extraction stage.Tentative effort was also done for the removal of extractedcontaminants from recycled liquefied gases.

  16. Effects of pulse current on energy consumption and removal of heavy metals during electrodialytic soil remediation

    DEFF Research Database (Denmark)

    Sun, Tian R.; Ottosen, Lisbeth M.

    2012-01-01

    exchange membrane was the major contributor of energy consumption, and the pulse current could decrease the voltage drop of this part effectively. The overall removal of heavy metals in soil 1 (6–54%) was much higher than soil 2 (1–17%) due to the different acidification process and chemical speciation......The aims of this paper were to investigate the possibility for energy saving when using a pulsed electric field during electrodialytic soil remediation (EDR) and the effect of the pulsed current on removal of heavy metals. Eight experiments with constant and pulse current in the different...... industrially polluted soils were performed. At a current density of 0.1mA/cm2 in soil 1 and 0.2mA/cm2 in soil 2, there was no difference on energy consumption and removal of heavy metals between pulse current and constant current experiments, but at higher current experiments (i.e., 0.2mA/cm2 in soil 1 and 0...

  17. Effectiveness and harmful effects of removal sulphated black crust from granite using Nd:YAG nanosecond pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Pozo, S. [Dpto. Ingeniería de los Recursos Naturales y Medio Ambiente, ETSI Minas, University of Vigo, 36310 (Spain); Barreiro, P. [Dpto. Física Aplicada, E.T.S.I. Industriales, University of Vigo, 36310 (Spain); Rivas, T. [Dpto. Ingeniería de los Recursos Naturales y Medio Ambiente, ETSI Minas, University of Vigo, 36310 (Spain); González, P. [Dpto. Física Aplicada, E.T.S.I. Industriales, University of Vigo, 36310 (Spain); Fiorucci, M.P. [Centro de Investigacións Tecnolóxicas (CIT), University of A Coruña, 15403, Ferrol (Spain)

    2014-05-01

    Sulphated black crust is a common form of deterioration affecting stone used in monuments, usually occurs in contaminated atmospheres or urban environments. Its origin and cleaning have been studied extensively, for decades, in the case of carbonate rocks. Recent studies show that this form of alteration also affects granites. Scientific research on laser removal effectiveness of gypsum-rich black crust on granites needs to be scientifically addressed considering the inexistent references. This paper assesses the removal by laser of sulphate-rich black crusts on granite using the different harmonics of a Nd:YAG nanosecond pulsed laser (266 nm, 355 nm, 532 nm and 1064 nm). Effectiveness was evaluated using Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM–EDS), X-Ray Diffraction (XRD) and Attenuated Total Reflection-Fourier Infrared Transform Spectroscopy (ATR-FTIR). We also evaluated the effect of the radiation on granite-forming minerals and on the colour of the stone using Scanning Electron Microscopy and spectrophotometry colour measurements respectively. SEM–EDS, XRD and ATR-FTIR analyses show that the higher the wavelength, the more efficient the cleaning, so samples cleaned using 1064 nm pulsed laser recovered its original colour. Nevertheless, the Nd:YAG laser did not completely eliminate the crust, and gypsum crystals remaining on the rock surface are observed, even at the most effective wavelength.

  18. Polychlorinated biphenyls removal from contaminated soils using a transportable indirect thermal dryer unit: implications for emissions.

    Science.gov (United States)

    Yang, Bing; Xue, Nandong; Ding, Qiong; Vogt, Rolf David; Zhou, Lingli; Li, Fasheng; Wu, Guanglong; Zhang, Shilei; Zhou, Dandan; Liu, Bo; Yan, Yunzhong

    2014-11-01

    An assessment in China of the application of a transportable indirect thermal dryer unit for the remediation of soils contaminated with polychlorinated biphenyls (PCBs) demonstrated that it is well suited to remove PCBs from soils. A remarkable reduction of total PCBs in soils from 163-770 μg g(-1) to 0.08-0.15 μg g(-1) was achieved. This represented removal efficiencies of greater than 99.9% and an approximate 100% removal of the toxic equivalent of the PCBs. Furthermore, the emissions to the atmosphere from the unit were in compliance with current PCBs regulations. In conclusion, remediation of PCBs-contaminated soils based on a transportable indirect thermal dryer unit appears to be a highly efficient and environmentally sound treatment technology that has huge implications for cleaning thousands of regionally dispersed sites of PCBs contamination in China.

  19. Detection and removal of impurities in nitric oxide generated from air by pulsed electrical discharge.

    Science.gov (United States)

    Yu, Binglan; Blaesi, Aron H; Casey, Noel; Raykhtsaum, Grigory; Zazzeron, Luca; Jones, Rosemary; Morrese, Alexander; Dobrynin, Danil; Malhotra, Rajeev; Bloch, Donald B; Goldstein, Lee E; Zapol, Warren M

    2016-11-30

    Inhalation of nitric oxide (NO) produces selective pulmonary vasodilation without dilating the systemic circulation. However, the current NO/N2 cylinder delivery system is cumbersome and expensive. We developed a lightweight, portable, and economical device to generate NO from air by pulsed electrical discharge. The objective of this study was to investigate and optimize the purity and safety of NO generated by this device. By using low temperature streamer discharges in the plasma generator, we produced therapeutic levels of NO with very low levels of nitrogen dioxide (NO2) and ozone. Despite the low temperature, spark generation eroded the surface of the electrodes, contaminating the gas stream with metal particles. During prolonged NO generation there was gradual loss of the iridium high-voltage tip (-90 μg/day) and the platinum-nickel ground electrode (-55 μg/day). Metal particles released from the electrodes were trapped by a high-efficiency particulate air (HEPA) filter. Quadrupole mass spectroscopy measurements of effluent gas during plasma NO generation showed that a single HEPA filter removed all of the metal particles. Mice were exposed to breathing 50 parts per million of electrically generated NO in air for 28 days with only a scavenger and no HEPA filter; the mice did not develop pulmonary inflammation or structural changes and iridium and platinum particles were not detected in the lungs of these mice. In conclusion, an electric plasma generator produced therapeutic levels of NO from air; scavenging and filtration effectively eliminated metallic impurities from the effluent gas. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Effectiveness of hand-cleansing agents for removing Acinetobacter baumannii strain from contaminated hands.

    Science.gov (United States)

    Cardoso, C L; Pereira, H H; Zequim, J C; Guilhermetti, M

    1999-08-01

    The effectiveness of hand-cleansing agents (plain liquid soap, 70% ethyl alcohol, 10% povidone-iodine, and 4% chlorhexidine gluconate) for removing a hospital strain of Acinetobacter baumannii from artificially contaminated hands of 5 volunteers was studied. The experiments were performed by using a Latin square statistical design, with two 5 x 4 randomized blocks, and the results were estimated by ANOVA. In the first and second blocks, the fingertips of the volunteers were contaminated with approximately 10(3) colony-forming units (light contamination hand) and 10(6) colony-forming units (heavy contamination hand), respectively. In the first block, all products tested were effective, almost completely removing the microbial population of A baumannii artificially applied to the hands. In the second block, the use of hand-cleansing agents resulted in 91.36% (4% chlorhexidine), 92.33% (liquid soap), 98.49% (10% povidone-iodine), and 98.93% (70% ethyl alcohol) reduction in counts of A baumannii cells applied to the fingertips. The ethyl alcohol and povidone-iodine had significantly higher removal rates than plain soap and chlorhexidine (P effective hand-cleansing agents for removing A baumannii strain from heavily contaminated hands (10(6) colony-forming units/fingertip).

  1. A Mini-review of Carbonaceous Nanomaterials for Removal of Contaminants from Wastewater

    Science.gov (United States)

    Shan, S. J.; Zhao, Y.; Tang, H.; Cui, F. Y.

    2017-05-01

    Recently, carbonaceous nanomaterials have been extensively studied for all sorts of contaminants removal from wastewater due to its extraordinary and tunable properties. The present and potential applications of these nanomaterials in wastewater treatment include adsorption, photocatalysis, disinfection, membranes process and other utilizations such as monitoring and desalination. In this paper, we concisely overview the current advances in carbonaceous nanomaterials, covering the basic information upon these nanomaterials (e.g., categories, structure, versatile properties) and their roles for removing diverse contaminants in different applications. Furthermore, the challenges and prospects for further utilizations are also outlined.

  2. Biotreatment of produced waters for volume reduction and contaminant removal

    Energy Technology Data Exchange (ETDEWEB)

    Negri, M.C.; Hinchman, R.R. [Argonne National Lab., IL (United States); Mollock, J. [Devon Energy Corp., Oklahoma City, OK (United States)

    1997-10-01

    Produced water is wastewater that is brought to the surface from natural gas wells during natural gas production. Its constituents, mostly salt, with traces of hydrocarbons and heavy metals, are a significant disposal problem. Argonne National Laboratory (ANL), in partnership with the Gas Research Institute (GRI), has developed a low-cost, low-tech method, in which green plants are used to reduce the volume of produced water. The authors have designed an engineered bioreactor system, which is modeled after natural saline wetland ecosystems. The plant bioreactor system maximizes plant evapotranspiration to reduce wastewater volume and, concurrently, may function as a biological filter to enhance contaminant degradation and immobilization in the root/rhizosphere zone. Halophyte plant species having high salt tolerance and high transpiration rates were selected after they tested them in greenhouse experiments. Models obtained by using their greenhouse findings reduced the volume of the wastewater (up to 6% salt) by 75% in about 8 days. A field demonstration of the bioreactor, designed on the basis of the results from the greenhouse study, is successfully under way at a natural gas well site in Oklahoma. The process could offer the petroleum industry a low-cost biological alternative to existing expensive options.

  3. Contaminant removal by wastewater treatment plants in the Stillaguamish River Basin, Washington

    Science.gov (United States)

    Barbash, Jack E.; Moran, Patrick W.; Wagner, Richard J.; Wolanek, Michael

    2015-01-01

    Human activities in most areas of the developed world typically release nutrients, pharmaceuticals, personal care products, pesticides, and other contaminants into the environment, many of which reach freshwater ecosystems. In urbanized areas, wastewater treatment plants (WWTPs) are critical facilities for collecting and reducing the amounts of wastewater contaminants (WWCs) that ultimately discharge to rivers, coastal areas, and groundwater. Most WWTPs use multiple methods to remove contaminants from wastewater. These include physical methods to remove solid materials (primary treatment), biological and chemical methods to remove most organic matter (secondary treatment), advanced methods to reduce the concentrations of various contaminants such as nitrogen, phosphorus and (or) synthetic organic compounds (tertiary treatment), and disinfection prior to discharge (Metcalf and Eddy, Inc., 1979). This study examined the extent to which 114 organic WWCs were removed by each of three WWTPs, prior to discharge to freshwater and marine ecosystems, in a rapidly developing area in northwestern Washington State. Removal percentages for each WWC were estimated by comparing the concentrations measured in the WWTP influents with those measured in the effluents. The investigation was carried out in the 700-mi2Stillaguamish River Basin, the fifth largest watershed that discharges to Puget Sound (fig. 1).

  4. Removal of phenol by activated alumina bed in pulsed high-voltage electric field

    Institute of Scientific and Technical Information of China (English)

    ZHU Li-nan; MA Jun; YANG Shi-dong

    2007-01-01

    A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe2+. The removal rate of phenol could reach 72.1 % when air aeration flow rate was 1200 ml/min, and 88.2 % when 0.05 mmol/L Fe2+ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.

  5. Removing external DNA contamination from arthropod predators destined for molecular gut-content analysis.

    Science.gov (United States)

    Greenstone, Matthew H; Weber, Donald C; Coudron, Thomas A; Payton, Mark E; Hu, Jing S

    2012-05-01

    Ecological research requires large samples for statistical validity, typically hundreds or thousands of individuals, which are most efficiently gathered by mass-collecting techniques. For the study of interspecific interactions, molecular gut-content analysis enables detection of arthropod predation with minimal disruption of community interactions. Field experiments have demonstrated that standard mass-collection methods, such as sweep netting, vacuum sampling and foliage beating, sometimes lead to contamination of predators with nontarget DNA, thereby compromising resultant gut-content data. We deliberately contaminated immature Coleomegilla maculata and Podisus maculiventris that had been fed larvae of Leptinotarsa decemlineata by topically applying homogenate of the alternate prey Leptinotarsa juncta. We then attempted to remove contaminating DNA by washing in ethanol or bleach. A 40-min wash with end-over-end rotation in 80% EtOH did not reliably reduce external DNA contamination. Identical treatment with 2.5% commercial bleach removed most externally contaminating DNA without affecting the detectability of the target prey DNA in the gut. Use of this bleaching protocol, perhaps with minor modifications tailored to different predator-prey systems, should reliably eliminate external DNA contamination, thereby alleviating concerns about this possible source of cross-contamination for mass-collected arthropod predators destined for molecular gut-content analysis. Published 2012. This article is a US Government work and is in the public domain in the USA.

  6. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation.

    Science.gov (United States)

    Secondes, Mona Freda N; Naddeo, Vincenzo; Belgiorno, Vincenzo; Ballesteros, Florencio

    2014-01-15

    Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs.

  7. Removal of organic contaminants by RO and NF membranes

    Science.gov (United States)

    Yoon, Yeomin; Lueptow, Richard M.

    2005-01-01

    Rejection characteristics of organic and inorganic compounds were examined for six reverse osmosis (RO) membranes and two nanofiltration (NF) membranes that are commercially available. A batch stirred-cell was employed to determine the membrane flux and the solute rejection for solutions at various concentrations and different pH conditions. The results show that for ionic solutes the degree of separation is influenced mainly by electrostatic exclusion, while for organic solutes the removal depends mainly upon the solute radius and molecular structure. In order to provide a better understanding of rejection mechanisms for the RO and NF membranes, the ratio of solute radius (r(i,s)) to effective membrane pore radius (r(p)) was employed to compare rejections. An empirical relation for the dependence of the rejection of organic compounds on the ratio r(i,s)/r(p) is presented. The rejection for organic compounds is over 75% when r(i,s)/r(p) is greater than 0.8. In addition, the rejection of organic compounds is examined using the extended Nernst-Planck equation coupled with a steric hindrance model. The transport of organic solutes is controlled mainly by diffusion for the compounds that have a high r(i,s)/r(p) ratio, while convection is dominant for compounds that have a small r(i,s)/r(p) ratio. c2005 Elsevier B.V. All rights reserved.

  8. Sequential Remediation Processes for Effective Removal of Oil from Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Deepika Dave

    2011-01-01

    Full Text Available Problem statement: Over 2.2 billions of oil and oil products are transported every year and often these activities can result in air, water and soil contamination. Expousure to petroleum products can cause health problems to humn and animals and affect marine animals and wildlife habitats. Approach: The objective of this study was to develop a technology for the remediation of soil contaminated with petroleum hydrocarbons. The remediation method included three processes: (a an effective soil washing process for the removal of the hydrocarbons from the contaminated soil, (b an efficient water decontamination process using peat moss as an oil absorbent and (c an effective bioremediation process for converting the oil in peat moss into carbon dioxide and water. Results: The results showed that water is an effective solvent for the removal of oil from contaminated soil. It has also been determined that peat moss is an effective absorbent and could be used to remove oil from the contaminated water. Peat can absorb 12.6 times its weight liquid (water/oil. The bioremediation process was effective in degrading the oil into harmless carbon dioxide and water products. About 77.65% of the THC was removed within 60 days of bioremediation. The hemophilic microbial population in the compost quickly acclimatized to the hydrocarbon as was evident from the immediate rise in the reactor temperature. The C: N ratio decreased from 30:1-12:1 indicating the degradation of organic C in the petroleum hydrocarbons and the peat. Urea was a very effective source of nitrogen in initiating and maintaining intense microbial respiration activity. Conclusion: A sequential processes for the remediation of oil contaminated soil was developed. These included soil washing, absorption of oil from water using peat and bioremediation of contaminated peat. A degradation model was developed and used to calculate the time required for a complete degradation. The model indicated that a

  9. The contaminant removal efficiency of an air cleaner using the adsorption/desorption effect

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Hiroshi [Toyohashi University of Technology, 1-1 Hibariga-oka, Tempakucho, Toyohashi 441-8580 (Japan); Shimizu, Masayuki [Sala Housing Corporation, Toyohashi 441-8021 (Japan); Sato, Hiroyasu [TOENEC Corporation, Nagoya 460-0008 (Japan)

    2009-07-15

    The adsorption and desorption of volatile organic compounds (VOCs) in relation to material surfaces were conducted to control indoor air quality. The VOC removal performance of building materials using sorption effects was validated in cases related to poor indoor air quality that occurred during non-ventilation periods during intermittent-ventilation situations. The objective of this investigation is to present the contaminant removal efficiency and practicality of a prototype air cleaner which uses sorption effects. Toluene and formaldehyde were used as pollutant sources and were continuously emitted into the test chamber. Effects due to the number of sorption units, operation time and mode of contaminant removal performance were examined. The sorption materials evaluated in this investigation were a porous material, zeolite, pumice stone and hydro-corn. As a result of the experiments, zeolite exhibited relatively high contaminant removal efficiency with toluene, and zeolite and the porous material exhibited high removal efficiency with formaldehyde for both one-cycle and two-cycle sorption modes. Moreover, significant removal performances were observed in the numerical analysis of the continuous-operation mode. (author)

  10. Development and evaluation of a novel product to remove surface contamination of hazardous drugs.

    Science.gov (United States)

    Cox, Joshua; Speed, Vonni; O'Neal, Sara; Hasselwander, Terry; Sherwood, Candice; Eckel, Stephen F; Zamboni, William C

    2017-03-01

    Background Even while following best practices, surface exposures of hazardous drugs (HDs) are high and numerous. Thus, it is important to develop new products to reduce the surface contamination of HDs. Hazardous Drug Clean (HDClean™) was developed to decontaminate and remove HDs from various types of surfaces and overcome the problems associated with other cleaning products. Methods HDClean was evaluated to remove mock surface exposures of HDs (docetaxel, paclitaxel, ifosfamide, cyclophosphamide, 5-FU, and cisplatin) from various types of surfaces. In two separate cancer centers, studies were performed to evaluate HDClean in reducing surface contamination of HDs in the pharmacy departments where no closed system transfer device (CSTD) was used. In a third cancer center, studies were performed comparing the effectiveness of a CSTD + Surface Safe compared with CSTD + HDClean to remove HDs. Results HDClean was able to completely remove mock exposures of a wide range of HDs from various surfaces (4 and 8 sq ft areas). Daily use of HDClean was equal to or more effective in reducing surface contamination of HDs in two pharmacies compared with a CSTD. HDClean was significantly more effective in removing HDs, especially cisplatin, compared with Surface Safe and does not have the problems associated with decontamination solutions that contain sodium hypochlorite. Conclusion These studies support HDClean as an effective decontaminating product, that HDClean is more effective than Surface Safe in removing HDs and is equal to or more effective than CSTD in controlling HD surface exposures.

  11. Effect of Co-Contaminant on Denitrification Removal of Nitrate in Drinking Water

    Directory of Open Access Journals (Sweden)

    Arzu KILIÇ

    2012-12-01

    Full Text Available In recent years, nitrogenous fertilizers used in agriculture, unconscious and without treatment wastewater is discharged led to an increase in groundwater nitrate pollution. In many countries, nitrate concentration in the ground waters used as drinking water source exceeded the maximum allowable concentration of 10 mg/L NO3-N. According to a study, some wells in the Harran Plain contain nitrate as high as 180 mg/L NO3--N and the average concentration for whole plain is 35 mg/L NO3--N (Yesilnacar et al., 2008. Additionally, increased water consumption, unconscious use of fertilizers and pesticides has led to the emergence of co-contaminant in drinking water. Recently, hazardous to human health co-contaminant such as arsenic, pesticides, perchlorate, selenate, chromate, uranium are observed in the nitrate pollution drinking water. There are many processes used for the removal of nitrate. The physical–chemical technologies that can be used for nitrate removal are reverse osmosis, ion exchange and electrodialysis (Alvarez et al., 2007. Important disadvantages of these processes are their poor selectivity, high operation and maintenance costs and the generation of brine wastes after treatment. Consequently, biological treatment processes to convert nitrates to benign dinitrogen gas, could be an interesting alternative for the remediation of groundwater contaminated with nitrates. The aim of this article, effective and cheap method for the removal of nitrate from drinking water biological denitrification is to examine the usability of contaminated drinking water with co-contaminant pollutions.

  12. Simultaneous removal of phenanthrene and lead from artificially contaminated soils with glycine-β-cyclodextrin.

    Science.gov (United States)

    Wang, Guanghui; Zhou, Yueming; Wang, Xuegang; Chai, Xinjun; Huang, Lei; Deng, Nansheng

    2010-12-15

    Preparation of glycine-β-cyclodextrin (GCD) was carried out by the reaction of β-cyclodextrin with glycine in the presence of KOH and epichlorohydrin. The enhanced solubilization behavior of phenanthrene and lead carbonate by GCD was studied, and the desorption behavior of phenanthrene and lead from co-contaminated soil was also investigated. The results showed that GCD has obvious solubilization for phenanthrene and lead carbonate. The solubility of phenanthrene in 30 g/L of GCD was enhanced about 30-fold. And the apparent aqueous solubilities of lead carbonate are also obviously increased with increasing GCD concentration, when the concentration of GCD reached 20 g/L, the aqueous lead concentration was 2945 mg/L. GCD could simultaneously increase the apparent aqueous solubility of phenanthrene and complex with lead. The desorption process of GCD for phenanthrene and lead from co-contaminated soil followed the pseudo-second-order kinetic model. The removal efficiencies of phenanthrene and lead in soil increased dramatically with increasing GCD concentrations. At concentration of 40 g/L, GCD has a removal efficiency of 85.8% and 78.8% for lead and phenanthrene, respectively, from the combined contaminated soil. The use of GCD as an extractant to enhance the removal of heavy and hydrophobic organic contaminants (HOCs) from co-contaminated soils appears as a promising remediation method.

  13. Treatment of volatile organic contaminants in a vertical flow filter: Relevance of different removal processes

    NARCIS (Netherlands)

    De Biase, C.; Reger, D.; Schmidt, A.; Jechalke, S.; Reiche, N.; Martínez-Lavanchy, P.M.; Rosell, M.; Van Afferden, M.; Maier, U.; Oswald, S.E.; Thullner, M.

    2011-01-01

    Vertical flow filters and vertical flow constructed wetlands are established wastewater treatment systems and have also been proposed for the treatment of contaminated groundwater. This study investigates the removal processes of volatile organic compounds in a pilot-scale vertical flow filter. The

  14. Treatment of volatile organic contaminants in a vertical flow filter: Relevance of different removal processes

    NARCIS (Netherlands)

    De Biase, C.; Reger, D.; Schmidt, A.; Jechalke, S.; Reiche, N.; Martínez-Lavanchy, P.M.; Rosell, M.; Van Afferden, M.; Maier, U.; Oswald, S.E.; Thullner, M.

    2011-01-01

    Vertical flow filters and vertical flow constructed wetlands are established wastewater treatment systems and have also been proposed for the treatment of contaminated groundwater. This study investigates the removal processes of volatile organic compounds in a pilot-scale vertical flow filter.

  15. Method of removing arsenic and other anionic contaminants from contaminated water using enhanced coagulation

    Science.gov (United States)

    Teter, David M.; Brady, Patrick V.; Krumhansl, James L.; Khandaker, Nadim R.

    2006-11-21

    An improved water decontamination process comprising contacting water containing anionic contaminants with an enhanced coagulant to form an enhanced floc, which more efficiently binds anionic species (e.g., arsenate, arsenite, chromate, fluoride, selenate, and borate, and combinations thereof) predominantly through the formation of surface complexes. The enhanced coagulant comprises a trivalent metal cation coagulant (e.g., ferric chloride or aluminum sulfate) mixed with a divalent metal cation modifier (e.g., copper sulfate or zinc sulfate).

  16. How do copper contamination pulses shape the regime shifts of phytoplankton-zooplankton dynamics?

    Science.gov (United States)

    Camara, B. I.; Yamapi, R.; Mokrani, H.

    2017-07-01

    The presence of pollutants in waters, particularly from heavy metals, is of grave concern worldwide due to its cytotoxicity to organisms. Fish and aquatic organisms are very sensitive to the increasing Cu concentrations in water. Therefore, Cu toxicity partly depends on water quality. To address the effects of impulsive copper contamination of the phytoplankton-zooplankton population dynamics, we've built a model that focuses on the interaction between algae and Daphnia with deterministic and stochastic impulse copper. In fact the Results have shown three types of outcomes depending on copper concentration. In low (4.4 μgL-1) copper concentration, deterministic and stochastic pulses may promote the persistence of Daphnia and algae populations unlike the absence of pulses. Whereas, in high (28 μgL-1) concentration, it accelerates deficiency and toxicity processes, leads to the extinction of all populations and in intermediate concentrations. Deterministic and stochastic pulses may transform population dynamics in complex oscillations. Numerical results show that the system that has been considered has more complex dynamics including bifurcation, period-doubling oscillations and chaos. Depending on minimum copper concentration in the environment, the bifurcation diagram has highlighted the resilience or the regime shifts of the system in occurrence of pulse contamination.

  17. Assessing Changes to Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    Science.gov (United States)

    Restoration of rivers and their associated ecosystems is a growing priority for government agencies (e.g., NOAA, USDA), as well as conservation organizations. Dam removal is a major component of many restoration projects credited with reintroducing fish species, improving water ...

  18. Removal of contaminants in leachate from landfill by waste steel scrap and converter slag.

    Science.gov (United States)

    Oh, Byung-Taek; Lee, Jai-Young; Yoon, Jeyong

    2007-08-01

    This study may be the first investigation to be performed into the potential benefits of recycling industrial waste in controlling contaminants in leachate. Batch reactors were used to evaluate the efficacy of waste steel scrap and converter slag to treat mixed contaminants using mimic leachate solution. The waste steel scrap was prepared through pre-treatment by an acid-washed step, which retained both zero-valent iron site and iron oxide site. Extensive trichloroethene (TCE) removal (95%) occurred by acid-washed steel scrap within 48 h. In addition, dehalogenation (Cl(-) production) was observed to be above 7.5% of the added TCE on a molar basis for 48 h. The waste steel scrap also removed tetrachloroethylene (PCE) through the dehalogenation process although to a lesser extent than TCE. Heavy metals (Cr, Mn, Cu, Zn, As, Cd, and Pb) were extensively removed by both acid-washed steel scrap and converter slag through the adsorption process. Among salt ions (NH (4)(+) , NO (3)(-) , and PO (4)(3-) ), PO (4)(3-) was removed by both waste steel scrap (100% within 8 h) and converter slag (100% within 20 min), whereas NO (3)(-) and NH (4)(+ ) were removed by waste steel scrap (100% within 7 days) and converter slag (up to 50% within 4 days) respectively. This work suggests that permeable reactive barriers (PRBs) with waste steel scrap and converter slag might be an effective approach to intercepting mixed contaminants in leachate from landfill.

  19. Removal of polycyclic aromatic hydrocarbons from aged-contaminated soil using cyclodextrins: Experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Viglianti, Christophe [Laboratoire d' Analyse Environnementale des Procedes et des Systemes Industriels - INSA de Lyon, 9, rue de la Physique - 69621 Villeurbanne Cedex (France); Centre Sciences, Information et Technologies pour l' Environnement (SITE) - ENS de Mines de Saint Etienne, 158 cours Fauriel - 42023 Saint Etienne Cedex 2 (France); Hanna, Khalil [Laboratoire d' Analyse Environnementale des Procedes et des Systemes Industriels - INSA de Lyon, 9, rue de la Physique - 69621 Villeurbanne Cedex (France)]. E-mail: khalilhanna@hotmail.com; Brauer, Christine de [Laboratoire d' Analyse Environnementale des Procedes et des Systemes Industriels - INSA de Lyon, 9, rue de la Physique - 69621 Villeurbanne Cedex (France); Germain, Patrick [Laboratoire d' Analyse Environnementale des Procedes et des Systemes Industriels - INSA de Lyon, 9, rue de la Physique - 69621 Villeurbanne Cedex (France)

    2006-04-15

    The removal of polycyclic aromatic hydrocarbons (PAHs) from soil using water as flushing agent is relatively ineffective due to their low aqueous solubility. However, addition of cyclodextrin (CD) in washing solutions has been shown to increase the removal efficiency several times. Herein are investigated the effectiveness of cyclodextrin to remove PAH occurring in industrially aged-contaminated soil. {beta}-Cyclodextrin (BCD), hydroxypropyl-{beta}-cyclodextrin (HPCD) and methyl-{beta}-cyclodextrin (MCD) solutions were used for soil flushing in column test to evaluate some influent parameters that can significantly increase the removal efficiency. The process parameters chosen were CD concentration, ratio of washing solution volume to soil weight, and temperature of washing solution. These parameters were found to have a significant and almost linear effect on PAH removal from the contaminated soil, except the temperature where no significant enhancement in PAH extraction was observed for temperature range from 5 to 35 {sup o}C. The PAHs extraction enhancement factor compared to water was about 200. - An innovative method using a biodegradable and non-toxic flushing agent for the depollution of industrially aged-contaminated soil.

  20. Study on SO2 Removal Efficiency by Nanosecond Rising Edge Pulse DBD Under Different Environmental Conditions

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-hua; SU Biao; LIU Ding-xin; WANG Jun-hua; RONG Ming-zhe

    2007-01-01

    In this paper,an experimental study on SO2 removal by nanosecond rising edge pulse dielectric barrier discharge (DBD) plasma,generated by multi-needle-to-plane electrodes,is carried out.The mechanism of the effect of various factors,such as gap size between dielectric barrier and discharge needles,environmental humidity,and inlet speed of gas flow upon the removal efficiency of air purification is analyzed.The studies show that SO2 removal efficiency improves with the increase in the gap size between dielectric barrier and discharge needles in the case of a fixed space between two electrodes,and also improves with the increase in the environmental humidity.For a mixed gas with a fixed concentration,there is an optimal inlet speed of gas flow,which leads to the best removal efficiency.

  1. Ailanthus Altissima and Phragmites Australis for chromium removal from a contaminated soil.

    Science.gov (United States)

    Ranieri, Ezio; Fratino, Umberto; Petrella, Andrea; Torretta, Vincenzo; Rada, Elena Cristina

    2016-08-01

    The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg(dry tissue)), compared with 358 mg Cr/kg(dry tissue) for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for Cr(VI) reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal.

  2. Simultaneous phenanthrene and cadmium removal from contaminated soil by a ligand/biosurfactant solution.

    Science.gov (United States)

    Lima, Tânia M S; Procópio, Lorena C; Brandão, Felipe D; Carvalho, André M X; Tótola, Marcos R; Borges, Arnaldo C

    2011-09-01

    Surfactants and inorganic ligands are pointed as efficient to simultaneous removal of heavy metals and hydrophobic organic pollutants from soil. However, the biosurfactants are potentially less toxic to soil organisms than other chemical agents. Thus, in this study the efficiency of combinations of iodide (I(-)) ligand and surfactants produced by different bacterial species in the simultaneous removal of cadmium (Cd(2+)) and phenanthrene in a Haplustox soil sample was investigated. Four microbial surfactants and the synthetic surfactant Triton X-100 were tested with different concentrations of ligand. Soil samples contaminated with Cd(2+) and phenanthrene underwent consecutive washings with a surfactant/ligand solution. The removal of Cd(2+) increased with increased ligand concentration, particularly in solutions containing biosurfactants produced by the bacterial strains Bacillus subtilis LBBMA155 (lipopeptide) and Flavobacterium sp. LBBMA168 (mixture of flavolipids) and Triton X-100. Maximum Cd(2+) removal efficiency was 99.2% for biosurfactant produced by Arthrobacter oxydans LBBMA 201 (lipopeptide) and 99.2% for biosurfactant produced by Bacillus sp. LBBMA111A (mixed lipopeptide) in the presence of 0.336 mol iodide l(-1), while the maximum efficiency of Triton X-100 removal was 65.0%. The biosurfactant solutions removed from 80 to 88.0% of phenanthrene in soil, and the removal was not influenced by the presence of the ligand. Triton X-100 removed from 73 to 88% of the phenanthrene and, differently from the biosurfactants, iodide influenced the removal efficiency. The results indicate that the use of a single washing agent, called surfactant-ligand, affords simultaneous removal of organic contaminants and heavy metals.

  3. Contaminated Sediment Management in Dam Removals and River Restoration Efforts: Critical Need for Research and Policy Development

    Science.gov (United States)

    Evans, J. E.

    2015-12-01

    Over 1,000 U.S. dams have been removed (1975-2015) for reasons including obsolescence, liability concerns, water quality upgrades, fisheries, or ecosystem enhancements. Contaminated sediment can significantly complicate the approval process, cost, and timeline of a dam removal, or stop it entirely. In a dam removal, reservoir sediment changes from a sink to a source of contaminants. Recently, the Sierra Club sued to stop the removal of a large dam in Ohio because of the potential impact of phosphate releases on toxic algal blooms in Lake Erie. Heavy metals, PCBs, PAHs, pesticides, and petroleum hydrocarbons can be present in reservoir sediments. In a non-dam removal scenario, reservoir management tools range from "no action" to dredging, dewatering and removal, or sediment capping. But it is not clear how these reservoir management techniques apply to dam removals. Case studies show typically >80% of the reservoir sediment is eventually eroded, precluding sediment capping as a containment option. However, the released contaminants are diluted by mixing with "clean" sediment and are transported to different physio-chemical environments which may immobilize or biodegrade the contaminants. Poorly understood options include phased drawdown/reseeding the former reservoir to contain sediments, diking contaminant "hot spots," and addressing contaminant stratigraphy (where historical use created "hot layers" in the reservoir sediment). Research and policy development needs include: (1) assessment methods based on synergistic effects of multiple contaminants being present; (2) ways to translate the pre-removal contaminant concentrations to post-removal health risks downstream; (3) evaluation of management practices for contaminant "hot spots" and "hot layers;" (4) tools to forecast the presence of contaminated sediment using easily accessible information; and (5) ways to limit liability risk for organizations participating in dam removals involving contaminated sediment.

  4. Chronic neuropathic facial pain after intense pulsed light hair removal. Clinical features and pharmacological management

    Science.gov (United States)

    Párraga-Manzol, Gabriela; Sánchez-Torres, Alba; Moreno-Arias, Gerardo

    2015-01-01

    Intense Pulsed Light (IPL) photodepilation is usually performed as a hair removal method. The treatment is recommended to be indicated by a physician, depending on each patient and on its characteristics. However, the use of laser devices by medical laypersons is frequent and it can suppose a risk of damage for the patients. Most side effects associated to IPL photodepilation are transient, minimal and disappear without sequelae. However, permanent side effects can occur. Some of the complications are laser related but many of them are caused by an operator error or mismanagement. In this work, we report a clinical case of a patient that developed a chronic neuropathic facial pain following IPL hair removal for unwanted hair in the upper lip. The specific diagnosis was painful post-traumatic trigeminal neuropathy, reference 13.1.2.3 according to the International Headache Society (IHS). Key words:Neuropathic facial pain, photodepilation, intense pulse light. PMID:26535105

  5. Advanced nitrogen removal by pulsed sequencing batch reactors (SBR) with real-time control

    Institute of Scientific and Technical Information of China (English)

    YANG Qing; PENG Yongzhen; YANG Anming; GUO Jianhua; LI Jianfeng

    2007-01-01

    The feasibility of pH and oxidation reduction potential (ORP) as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors (SBR)was evaluated.The pulsed SBR,a novel operational mode of SBR,was utilized to treat real municipal wastewater accompanied with adding ethanol as external carbon source.It was observed that the bending-point (apex and knee) of pH and ORP profiles can be used to control denitrification process at a low influent C/N ratio while dpH/dt can be used to control the nitrification and denitrification process at a high influent C/N ratio.The experimental results demonstrated that the effluent total nitrogen can be reduced to lower than 2 mg/L,and the average total nitrogen (TN) removal efficiency was higher than 98% by using real-time controll strategy.

  6. Pulsed electrical discharges in water for removal of organic pollutants: a comparative study

    OpenAIRE

    Dang, T.H.; Denat, A.; Lesaint, O.; Teissedre, G.

    2009-01-01

    Abstract In this study, the efficiency of different types of pulsed electrical discharges for the removal of organic pollutants from wastewater has been determined. Three discharge types, either in the water volume or in close proximity to the water surface are studied. The production of hydrogen peroxide in pure water, and the degradation of two typical pollutants (4-chlorophenol and 4-nitrophenol) is measured together with the amount of electrical energy d...

  7. Metal removal from contaminated soil and sediments by the biosurfactant surfactin

    Energy Technology Data Exchange (ETDEWEB)

    Mulligan, C.N.; Yong, R.N.; Gibbs, B.F.; James, S.; Bennett, H.P.J.

    1999-11-01

    Batch soil washing experiments were performed to evaluate the feasibility of using surfactin from Bacillus subtilis, a lipopeptide biosurfactant, for the removal of heavy metals from a contaminated soil and sediments. The soil contained high levels of metals and hydrocarbons (890 mg/kg of zinc, 420 mg/kg of copper, and 12.6% oil and grease), and the sediments contained 110 mg/kg of copper and 3,300 mg/kg of zinc. The contaminated soil was spiked to increase the level of copper, zinc, and cadmium to 550, 1,200, and 2,000 mg/kg, respectively. Water alone removed minimal amounts of copper and zinc (less than 1%). Results showed that 0.25% surfactin/1% NaOH could remove 25% of the copper and 6% of the zinc from the soil and 15% of the copper and 6% of the zinc from the sediments. A series of five washings of the soil with 0.25% surfactin (1% NaOH) was able to remove 70% of the copper and 22% of the zinc. The technique of ultrafiltration and the measurement of octanol-water partitioning and {zeta}-potential were used to determine the mechanism of metal removal by surfactin. It was indicated that surfactin was able to remove the metals by sorption at the soil interphase and metal complexation, followed by desorption of the metal through interfacial tension lowering and fluid forces and finally complexation of the metal with the micelles.

  8. Removal of heavy metals and arsenic from contaminated soils using bioremediation and chelant extraction techniques.

    Science.gov (United States)

    Vaxevanidou, Katerina; Papassiopi, Nymphodora; Paspaliaris, Ioannis

    2008-02-01

    A combined chemical and biological treatment scheme was evaluated in this study aiming at obtaining the simultaneous removal of metalloid arsenic and cationic heavy metals from contaminated soils. The treatment involved the use of the iron reducing microorganism Desulfuromonas palmitatis, whose activity was combined with the chelating strength of EDTA. Taking into consideration that soil iron oxides are the main scavengers of As, treatment with iron reducing microorganisms aimed at inducing the reductive dissolution of soil oxides and thus obtaining the release of the retained As. The main objective of using EDTA was the removal of metal contaminants, such as Pb and Zn, through the formation of soluble metal chelates. Experimental results however indicated that EDTA was also indispensable for the biological reduction of Fe(III) oxides. The bacterial activity was found to have a pronounced positive effect on the removal of arsenic, which increased from the value of 35% obtained during the pure chemical treatment up to 90% in the presence of D. palmitatis. In the case of Pb, the major part, i.e. approximately 85%, was removed from soil with purely chemical mechanisms, whereas the biological activity slightly improved the extraction, increasing the final removal up to 90%. Co-treatment had negative effect only for Zn, whose removal was reduced from 80% under abiotic condition to approximately 50% in the presence of bacteria.

  9. Pyrene removal from contaminated soil using electrokinetic process combined with surfactant

    Directory of Open Access Journals (Sweden)

    Seyed Enayat Hashemi

    2015-07-01

    Full Text Available Background: Pyrene is one of the stable polycyclic aromatic hydrocarbons that is considered as an important pollutants, because of extensive distribution in the environment and carcinogenic and mutagenic properties. Among the various treatment techniques, electrokinetic method is an environmental- friendly process for organic and mineral pollutants adsorbed to soil with fine pore size the same as clay and low hydraulic conductivity soils. For improving the efficiency of pyrene removal from soil, soulobilization of pyrene from soil could be used by surfactants. Materials and Methods : In this study, clay soil was selected as model because of the specific properties. Combined method using surfactant and electrokinetic was applied for pyrene removal from soil. Experiments were designed using response surface methodology (RSM, and effect of three variables includes surfactant concentration, voltage and surfactant type were evaluated for pyrene removal from contaminated soil. Results: Pyrene removal using anionic surfactants(SDS and nonionic surfactants(TX100 as a solubilizing agents has high removal efficiency. In the optimum condition with 95% confidence coefficient, utilizing mixed surfactants of sodium dodecyl sulfate and triton X-100 with the same volume, induced of 18.54 volt and 6.53 percent surfactant concentration have 94.6% pyrene removal efficiency. Conclusion:: Results of this study shows that electrokinetic process combined with surfactant as solubilizing agent could be applied as an efficient method for treating the pyrene-contaminated soils.

  10. Removal of metal contaminants and radionuclides with natural zeolites - competitive sorption and effects of zeolite modifications

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, K.V.; Prakash, A. [The Univ. of Western Ontario, Dept. of Chemical and Biochemical Engineering, London, ON (Canada); Vijayan, S. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2011-07-01

    Metal contaminants including radionuclides found in wastewaters must be reduced to acceptable levels before discharging the wastewater into receiving waters. These cations can accumulate in aquatic organisms causing toxicity and death, hence strict regulatory limits for their allowable discharge levels have been established over the years. This has also prompted the development of cost effective technologies that will permit the efficient removal of contaminants, while concentrating the contaminants in a form suitable for immobilization, storage and disposal. Removal requirements can be met by some inorganic zeolites, which can be natural or synthetic. The zeolites have a strong affinity for transition metal cations, and their cage-like structures offer large internal and external surface areas for ion exchange and adsorption. In view of these considerations, investigations with two low-cost natural zeolites (clinoptilolite and chabazite) were started, with the objective of developing a cost effective technology for column operations. Sorption tests of Cs{sup +}, Sr{sup 2+} and Cu{sup 2+} ions on chabazite and clinoptilolite were carried out using batch experiments in 125 mL vessels under various test conditions. Competitive sorption was studied in mixed cation solutions containing the commonly occurring non-toxic cations Ca{sup 2+} and Na{sup +}. The presence of these non-toxic cations inhibits removal of the targeted cations. Additional pretreatments and modifications of the 'as received' sorbent particles were also investigated, which are important in multiple cation systems, to enhance removal selectivity for the target contaminant cations. Sorption tests with chabazite and clinoptilolite showed that these two natural zeolites can be effectively used to remove cesium, strontium and copper ions from aqueous solutions. The performance can be controlled by maintaining the zeolite to waste volume ratio. The contaminant removal performance of chabazite was

  11. Comparative assessment of LECA and Spartina maritima to remove emerging organic contaminants from wastewater.

    Science.gov (United States)

    Ferreira, Ana Rita; Guedes, Paula; Mateus, Eduardo P; Ribeiro, Alexandra B; Couto, Nazaré

    2017-03-01

    The present work aimed to evaluate the capacity of constructed wetlands (CWs) to remove three emerging organic contaminants with different physicochemical properties: caffeine (CAF), oxybenzone (MBPh), and triclosan (TCS). The simulated CWs were set up with a matrix of light expanded clay aggregates (LECA) and planted with Spartina maritima, a salt marsh plant. Controlled experiments were carried out in microcosms using deionized water and wastewater collected at a wastewater treatment plant (WWTP), with different contaminant mass ranges, for 3, 7, and 14 days. The effects of variables were tested isolatedly and together (LECA and/or S. maritima). The presence of LECA and/or S. maritima has shown higher removal (around 61-97%) of lipophilic compounds (MBPh and TCS) than the hydrophilic compound (CAF; around 19-85%). This was attributed to the fact that hydrophilic compounds are dissolved in the water column, whereas the lipophilic ones suffer sorption processes promoting their removal by plant roots and/or LECA. In the control (only wastewater), a decrease in the three contaminant levels was observed. Adsorption and bio/rhizoremediation are the strongest hypothesis to explain the decrease in contaminants in the tested conditions.

  12. Contaminant Removal from Oxygen Production Systems for In Situ Resource Utilization

    Science.gov (United States)

    Anthony, Stephen M.; Santiago-Maldonado, Edgardo; Captain, James G.; Pawate, Ashtamurthy S.; Kenis, Paul J. A.

    2012-01-01

    The In Situ Resource Utilization (ISRU) project has been developing technologies to produce oxygen from lunar regolith to provide consumables to a lunar outpost. The processes developed reduce metal oxides in the regolith to produce water, which is then electrolyzed to produce oxygen. Hydrochloic and hydrofluoric acids are byproducts of the reduction processes, as halide minerals are also reduced at oxide reduction conditions. Because of the stringent water quality requirements for electrolysis, there is a need for a contaminant removal process. The Contaminant Removal from Oxygen Production Systems (CROPS) team has been developing a separation process to remove these contaminants in the gas and liquid phase that eliminates the need for consumables. CROPS has been using Nafion, a highly water selective polymeric proton exchange membrane, to recover pure water from the contaminated solution. Membrane thickness, product stream flow rate, and acid solution temperature and concentration were varied with the goal of maximizing water permeation and acid rejection. The results show that water permeation increases with increasing solution temperature and product stream flow rate, while acid rejection increases with decreasing solution temperature and concentration. Thinner membranes allowed for higher water flux and acid rejection than thicker ones. These results were used in the development of the hardware built for the most recent Mars ISRU demonstration project.

  13. A combined process coupling phytoremediation and in situ flushing for removal of arsenic in contaminated soil.

    Science.gov (United States)

    Yan, Xiulan; Liu, Qiuxin; Wang, Jianyi; Liao, Xiaoyong

    2017-07-01

    Phytoremediation and soil washing are both potentially useful for remediating arsenic (As)-contaminated soils. We evaluated the effectiveness of a combined process coupling phytoremediation and in situ soil flushing for removal of As in contaminated soil through a pilot study. The results showed that growing Pteris vittata L. (P.v.) accompanied by soil flushing of phosphate (P.v./Flushing treatment) could significantly decrease the total As concentration of soil over a 37day flushing period compared with the single flushing (Flushing treatment). The P.v./Flushing treatment removed 54.04% of soil As from contaminated soil compared to 47.16% in Flushing treatment, suggesting that the growth of P. vittata was beneficial for promoting the removal efficiency. We analyzed the As fractionation in soil and As concentration in soil solution to reveal the mechanism behind this combined process. Results showed that comparing with the control treatment, the percent of labile arsenate fraction significantly increased by 17% under P.v./Flushing treatment. As concentration in soil solution remained a high lever during the middle and later periods (51.26-56.22mg/L), which was significantly higher than the Flushing treatment. Although soil flushing of phosphate for more than a month, P. vittata still had good accumulation and transfer capacity of As of the soil. The results of the research revealed that combination of phytoremediation and in situ soil flushing is available to remediate As-contaminated soils. Copyright © 2016. Published by Elsevier B.V.

  14. Study on Decomposition of Indoor Air Contaminants by Pulsed Atmospheric Microplasma

    OpenAIRE

    Tomoya Kuwabara; Marius Blajan; Kazuo Shimizu

    2012-01-01

    Decomposition of formaldehyde (HCHO) by a microplasma reactor in order to improve Indoor Air Quality (IAQ) was achieved. HCHO was removed from air using one pass through reactor treatment (5 L/min). From an initial concentration of HCHO of 0.7 ppm about 96% was removed in one pass treatment using a discharge power of 0.3 W provided by a high voltage amplifier and a Marx Generator with MOSFET switches as pulsed power supplies. Moreover microplasma driven by the Marx Generator did not generate ...

  15. Effectiveness of hand-cleansing agents for removing methicillin-resistant Staphylococcus aureus from contaminated hands.

    Science.gov (United States)

    Guilhermetti, M; Hernandes, S E; Fukushigue, Y; Garcia, L B; Cardoso, C L

    2001-02-01

    The effectiveness of hand-cleansing agents in removing a hospital strain of methicillin-resistant Staphylococcus aureus from artificially contaminated hands of five volunteers was studied. The products used were plain liquid soap, ethyl alcohol 70% (by weight), 10% povidone-iodine liquid soap (PVP-I), and chlorhexidine gluconate (4%) detergent. The experiments were performed using a Latin square statistical design, with two 5x4 randomized blocks. The removal rates of S aureus cells from contaminated fingertips were estimated by analysis of variance, the response variable being the log10 reduction factor (RF), ie, log10 of the initial counts minus log10 of the final counts. In the first and second blocks, the fingertips of the volunteers were contaminated in mean with 3.76 log10 colony-forming units ([CFU] light-contamination hand) and 6.82 log10 CFU (heavy-contamination hand), respectively. In the first block, there were significant differences between treatments (Pliquid soap (RF, 1.96) and 4% chlorhexidine (RF, 1.91). In the second block, 10% PVP-I (RF, 4.39) and 70% ethyl alcohol (RF, 3.27) also were significantly more effective than plain liquid soap (RF, 1.77) and 4% chlorhexidine (RF, 1.37; Pliquid soap was significantly more effective than chlorhexidine (4%) detergent. The results suggest that 10% PVP-I and 70% ethyl alcohol may be the most effective hand-cleansing agents for removing methicillin-resistant S aureus strain from either lightly or heavily contaminated hands.

  16. Contaminant removal from low-concentration polluted river water by the bio-rack wetlands.

    Science.gov (United States)

    Wang, Ji; Zhang, Lanying; Lu, Shaoyong; Jin, Xiangcan; Gan, Shu

    2012-01-01

    The bio-rack is a new approach for treating low-concentration polluted river water in wetland systems. A comparative study of the efficiency of contaminant removal between four plant species in bio-rack wetlands and between a bio-rack system and control system was conducted on a small-scale (500 mm length x 400 mm width x 400 mm height) to evaluate the decontamination effects of four different wetland plants. There was generally a significant difference in the removal of total nitrogen (TN), ammonia nitrogen (NH3-N) and total phosphorus (TP), but no significant difference in the removal of permanganate index (COD(Mn)) between the bio-rack wetland and control system. Bio-rack wetland planted with Thalia dealbata had higher nutrient removal rates than wetlands planted with other species. Plant fine-root (root diameter plant biomass was related to nutrient removal efficiency. The study suggested that the nutrient removal rates are influenced by plant species, and high fine-root biomass is an important factor in selecting highly effective wetland plants for a bio-rack system. According to the mass balance, the TN and TP removal were in the range of 61.03-73.27 g/m2 and 4.14-5.20 g/m2 in four bio-rack wetlands during the whole operational period. The N and P removal by plant uptake constituted 34.9%-43.81% of the mass N removal and 62.05%-74.81% of the mass P removal. The study showed that the nitrification/denitrification process and plant uptake process are major removal pathways for TN, while plant uptake is an effective removal pathway for TP.

  17. Contaminant removal from low-concentration polluted river water by the bid-rack wetlands

    Institute of Scientific and Technical Information of China (English)

    Ji Wang; Lanying Zhang; Shaoyong Lu; Xiangcan Jin; Shu Gan

    2012-01-01

    The bio-rack is a new approach for treating low-concentration polluted river water in wetland systems.A comparative study of the efficiency of contaminant removal between four plant species in bio-rack wetlands and between a bio-rack system and control system was conducted on a small-scale (500 mm length × 400 mm width × 400 mm height) to evaluate the decontamination effects of four different wedand plants.There was generally a significant difference in the removal of total nitrogen (TN),ammonia nitrogen (NH3-N) and total phosphorus (TP),but no significant difference in the removal of permanganate index (CODMn) between the bio-rack wetland and control system.Bio-rack wetland planted with Thalia dealbata had higher nutrient removal rates than wetlands planted with other species.Plant fine-root (root diameter ≤ 3 mm) biomass rather than total plant biomass was related to nutrient removal efficiency.The study suggested that the nutrient removal rates are influenced by plant species,and high fine-root biomass is an important factor in selecting highly effective wetland plants for a bio-rack system.According to the mass balance,the TN and TP removal were in the range of 61.03-73.27 g/m2 and 4.14-5.20 g/m2 in four bio-rack wetlands during the whole operational period.The N and P removal by plant uptake constituted 34.9%-43.81% of the mass N removal and 62.05%-74.81% of the mass P removal.The study showed that the nitrification/denitrification process and plant uptake process are major removal pathways for TN,while plant uptake is an effective removal pathway for TP.

  18. Process optimization for the removal of environmental contaminants from fish oils

    Directory of Open Access Journals (Sweden)

    Maes Jeroen

    2010-03-01

    Full Text Available Fish oils are rich in nutritionally valuable omega-3 components, mainly eicosapentaenoic (EPA and docosahexaenoic (DHA fatty acids. Unfortunately, they could also be contaminated with a series of toxic pollutants like PCDD/Fs and PCBs. This article focuses on the methods for removal of these unwanted compounds and at the same time preserving the nutritional quality of fish oil. Adsorption, deodorization, packed column stripping, and a combination of processes are reviewed here. Activated carbon at 0.5% dosage was efficient in adsorbing PCDD/Fs and no- PCBs, but only 58% of the mo- PCBs could be removed. Adsorption treatment did not significantly alter the quality of the oil. Simple packed column stripping and/or deodorization removed no-PCBs, and especially mo-PCBs in a better manner, its efficiency increasing with temperature. Nutritional properties were preserved until 210°C, beyond which significant EPA and DHA degradation was observed. Combination of activated carbon treatment and deodorization was a good method to remove contaminants, yet preserving the nutritional quality of fish oil. At deodorization temperature of 190°C and 0.1% AC dosage, the total contamination level of PCDD/Fs and dioxin-like PCBs could be reduced, independent of the process sequence, from 35 to below 10 pg TEQ/g, in accordance with the European Union (EU regulation.

  19. Distribution of Argon Arc Contaminated with Nitrogen as Function of Frequency in Pulsed TIG Welding

    Science.gov (United States)

    Takahashi, Hiroki; Tanaka, Tatsuro; Yamamoto, Shinji; Iwao, Toru

    2016-09-01

    TIG arc welding is the high-quality and much applicable material joining technology. However, the current has to be small because the cathode melting should be prevented. In this case, the heat input to the welding pool becomes low, then, the welding defect sometimes occurs. The pulsed TIG arc welding is used to improve this disadvantage This welding can be controlled by some current parameters such as frequency However, few report has reported the distribution of argon arc contaminated with nitrogen It is important to prevent the contamination of nitrogen because the melting depth increases in order to prevent the welding defects. In this paper, the distribution of argon arc contaminated as function of frequency with nitrogen in pulsed TIG welding is elucidated. The nitrogen concentration, the radial flow velocity, the arc temperature were calculated using the EMTF simulation when the time reached at the base current. As a result, the nitrogen concentration into the arc became low with increasing the frequency The diffusion coefficient decreased because of the decrement of temperature over 4000 K. In this case, the nitrogen concentration became low near the anode. Therefore, the nitrogen concentration became low because the frequency is high.

  20. Removal of Pb and MDF from contaminated soils by EDTA- and SDS-enhanced washing.

    Science.gov (United States)

    Zhang, Weihua; Tsang, Daniel C W; Lo, Irene M C

    2007-02-01

    Heavy metal- and organic-contaminated sites are ubiquitous, but few studies have been conducted to address such an issue. EDTA- and SDS-enhanced washing was studied for remediation of Pb- and/or marine diesel fuel (MDF)-contaminated soils. The feasibility of recovery and reuse of EDTA and SDS, as well as the physicochemical interactions among the chemical agents, contaminants and soils were extensively investigated using batch experiments. The optimal washing sequence was then determined. The experimental results showed that EDTA could be recovered and reused for four cycles without significant loss of its chelating capacity, while the extraction capability of SDS was noticeably reduced after each reuse cycle. The free phase of marine diesel fuel (MDF) in soils physically isolated the sorbed Pb on soils and thus reducing its extraction by EDTA. The presence of SDS alone or together with low concentration of EDTA was found to enhance Pb removal probably via electrostatic interaction and dissolution of soil organic matter. However, it hindered Pb extraction by high concentration of EDTA, because of the potential formation of complexes between some strongly-bound Pb and SDS, that are more resistant to desorption. Therefore, EDTA washing followed by SDS achieved the highest Pb removal efficiency. On the other hand, MDF removal by SDS was significantly hindered by coexisting Pb in soils, probably because the formation of Pb-dodecyl sulfate (DS) complex would decrease the effective amount of SDS available for forming micelles in solution and enhance MDF sorption. EDTA alone or together with SDS could enhance MDF removal, but the residual MDF after EDTA-washing became more resistant to SDS removal. Consequently, SDS washing followed by EDTA is considered as the optimal washing sequence for MDF removal.

  1. Selenium removal during a flood experiment: Best management practice for a contaminated wetland?

    Science.gov (United States)

    Naftz, D. L.; Yahnke, J.; Miller, J.; Noyes, S.

    2003-12-01

    Constructed and natural wetlands can accumulate elevated levels of selenium (Se); however, few data are available on cost-effective methods for remobilization and removal of Se from these areas. The experiment was conducted at Stewart Lake Waterfowl Management Area (SLWMA), a Se-contaminated wetland in northeastern Utah. The purpose of the experiment was to assess the effectiveness of flooding on the removal of Se from surface sediments and transport to the chemically reducing ground water 1.8 meters (m) below land surface. The 84-m2 flood-experiment plot contained 10 monitoring wells, a water-quality minimonitor (continuous measurement of pH, specific conductance, water temperature, and dissolved oxygen), a down-hole bromide (Br) electrode, and 2 pressure transducers. Flooding was initiated on August 27, 2002, and a Br tracer was added to water delivered through a pipeline to the flood plot. Standing water depth in the flood plot was maintained at 0.3 m through September 1, 2002. Mean vertical water velocities were estimated to range from 0.3 to 1.3 centimeters per hour. Dissolved (less than 0.45 micron) Se increased from pre-flood concentrations of less than 10 micrograms per liter (ug/L) to greater than 800 ug/L during flooding in samples from deep (1.8 m below land surface) ground water. Se concentrations exceeded 5,500 ug/L in samples from shallow (0.8 m below land surface) ground water. Ratios of Se to Br in water samples indicate that Se moved conservatively during the experiment and was derived from leaching of near-surface sediments. Cumulative Se flux to the deep ground water during the experiment ranged from 54.9 to 172 milligrams per square meter (mg/m2). Pre- and post-flood surface soil sampling indicated a mean Se flux of 750 mg/m2 through the top 15 centimeters of soil. Measurable Se flux to the deep ground water would have increased if the flood experiment had continued beyond September 1, 2002. Water samples from the deep ground water collected in

  2. Combination of biochar amendment and phytoremediation for hydrocarbon removal in petroleum-contaminated soil.

    Science.gov (United States)

    Han, Tao; Zhao, Zhipeng; Bartlam, Mark; Wang, Yingying

    2016-11-01

    Remediation of soils contaminated with petroleum is a challenging task. Four different bioremediation strategies, including natural attenuation, biochar amendment, phytoremediation with ryegrass, and a combination of biochar and ryegrass, were investigated with greenhouse pot experiments over a 90-day period. The results showed that planting ryegrass in soil can significantly improve the removal rate of total petroleum hydrocarbons (TPHs) and the number of microorganisms. Within TPHs, the removal rate of total n-alkanes (45.83 %) was higher than that of polycyclic aromatic hydrocarbons (30.34 %). The amendment of biochar did not result in significant improvement of TPH removal. In contrast, it showed a clear negative impact on the growth of ryegrass and the removal of TPHs by ryegrass. The removal rate of TPHs was significantly lower after the amendment of biochar. The results indicated that planting ryegrass is an effective remediation strategy, while the amendment of biochar may not be suitable for the phytoremediation of soil contaminated with petroleum hydrocarbons.

  3. Removal of polycyclic aromatic hydrocarbons from aged-contaminated soil using cyclodextrins: experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Christophe Viglianti; Khalil Hanna; Christine de Brauer; Patrick Germain [Laboratoire d' Analyse Environnementale des Procedes et des Systemes Industriels - INSA de Lyon, Villeurbanne (France)

    2006-04-15

    The removal of polycyclic aromatic hydrocarbons (PAHs) from soil using water as flushing agent is relatively ineffective due to their low aqueous solubility. However, addition of cyclodextrin (CD) in washing solutions has been shown to increase the removal efficiency several times. Herein are investigated the effectiveness of cyclodextrin to remove PAH occurring in industrially aged-contaminated soil. {beta}-Cyclodextrin (BCD), hydroxypropyl-{beta}-cyclodextrin (HPCD) and methyl-{beta}-cyclodextrin (MCD) solutions were used for soil flushing in column test to evaluate some influent parameters that can significantly increase the removal efficiency. The process parameters chosen were CD concentration, ratio of washing solution volume to soil weight, and temperature of washing solution. These parameters were found to have a significant and almost linear effect on PAH removal from the contaminated soil, except the temperature where no significant enhancement in PAH extraction was observed for temperature range from 5 to 35{sup o}C. The PAHs extraction enhancement factor compared to water was about 200.

  4. Activated soil filters for removal of biocides from contaminated run-off and waste-waters

    DEFF Research Database (Denmark)

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael

    2011-01-01

    Building facades can be equipped with biocides to prevent formation of algal, fungal and bacterial films. Thus run-off waters may contain these highly active compounds. In this study, the removal of several groups of biocides from contaminated waters by means of an activated soil filter was studied....... A technical scale activated vertical soil filter (biofilter) with different layers (peat, sand and gravel), was planted with reed (Phragmites australis) and used to study the removal rates and fate of hydrophilic to moderate hydrophobic (log Kow 1.8–4.4) biocides and biocide metabolites such as: Terbutryn...

  5. Arsenic removal from contaminated soil via biovolatilization by genetically engineered bacteria under laboratory conditions

    Institute of Scientific and Technical Information of China (English)

    Shuang Liu; Fan Zhang; Jian Chen; Guoxin Sun

    2011-01-01

    In Rhodopseudomonas palustris,an arsM gene,encoding bacterial and archaeal homologues of the mammalian Cyt19 As(ⅢH)S-adenosylmethionine methytransferase,was regulated by arsenicals.An expression of arsM was introduced into strains for the methylation of arsenic.When arsM was expressed in Sphingomonas desiccabilis and Bacillus idriensis,it had 10 folds increase of methyled arsenic gas compared to wild type in aqueous system.In soil system,about 2.2%-4.5% of arsenic was removed by biovolatilization during 30 days.This study demonstrated that arsenic could be removed through volatilization from the contaminated soil by bacteria which have arsM gene expressed.These results showed that it is possible to use microorganisms expressing arsM as an inexnensive,effìcient strategy for arsenic bioremediation from contaminated water and soil.

  6. SLAG CHARACTERIZATION AND REMOVAL USING PULSE DETONATION TECHNOLOGY DURING COAL GASIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    DR. DANIEL MEI; DR. JIANREN ZHOU; DR. PAUL O. BINEY; DR. ZIAUL HUQUE

    1998-07-30

    Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. Conventional slag removal methods including soot blowers and water lances have great difficulties in removing slags especially from the down stream areas of utility power plant boilers. The detonation wave technique, based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. A slight increase in the boiler efficiency, due to more effective ash/deposit removal and corresponding reduction in plant maintenance downtime and increased heat transfer efficiency, will save millions of dollars in operational costs. Reductions in toxic emissions will also be accomplished due to reduction in coal usage. Detonation waves have been demonstrated experimentally to have exceptionally high shearing capability, important to the task of removing slag and fouling deposits. The experimental results describe the parametric study of the input parameters in removing the different types of slag and operating condition. The experimental results show that both the single and multi shot detonation waves have high potential in effectively removing slag deposit from boiler heat transfer surfaces. The results obtained are encouraging and satisfactory. A good indication has also been obtained from the agreement with the preliminary computational fluid dynamics analysis that the wave impacts are more effective in removing slag deposits from tube bundles rather than single tube. This report presents results obtained in effectively removing three different types of slag (economizer, reheater, and air-heater) t a distance of up to 20 cm from the exit of the detonation tube. The experimental results show that the softer slags can be removed more easily. Also closer the slag to the exit of

  7. Combination of biochar amendment and phytoremediation for hydrocarbon removal in petroleum-contaminated soil

    OpenAIRE

    Han, Tao; Zhao, Zhipeng; Bartlam, Mark; Wang, Yingying

    2016-01-01

    Remediation of soils contaminated with petroleum is a challenging task. Four different bioremediation strategies, including natural attenuation, biochar amendment, phytoremediation with ryegrass, and a combination of biochar and ryegrass, were investigated with greenhouse pot experiments over a 90-day period. The results showed that planting ryegrass in soil can significantly improve the removal rate of total petroleum hydrocarbons (TPHs) and the number of microorganisms. Within TPHs, the rem...

  8. Removal of PAHs from contaminated clayey soil by means of electro-osmosis

    KAUST Repository

    Lima, Ana T.

    2011-06-01

    The removal of polycyclic aromatic hydrocarbons (PAHs) from clayey soils is an intricate task. The low porosity of compacted clayey soil hinders bacterial activity and makes convective removal by hydraulic flow impossible. Electro-osmosis is a process that has been used for the mobilization and cleanup of contaminants in clayey soils with varying successes. The present study focuses on the remediation of a contaminated peaty clay soil, located in Olst - the Netherlands, by means of electro-osmosis. The soil was originally contaminated by an asphalt production plant, active from 1903 to 1983, and presents high levels of all 16 priority PAHs indicated by the US Environmental Protection Agency (EPA). Such a long contact times of PAH with the soil (≥100 years) presents a unique study material with well established solid/liquid contaminant partitioning equilibrium, preferable to artificially spiked soil. A batch of 6 electro-osmosis laboratory experiments was carried out to study the removal of 16 PAHs through electro-osmosis. In these experiments, water and a surfactant (Tween 80) were used to enhance the PAH desorption. The electro-osmotic conductivities ranged from 2.88 × 10-10 to a substantial 1.19 × 10-7 m2 V-1 s -1 when applying a current density of 0.005-0.127 A m-2. Electro-osmosis was expected to occur towards the cathode, because of natural soil characteristics (negative zeta potential), but presented scattered directions. The use of reference electrodes proved to be very effective to the prediction of the flow direction. Finally, the addition of Tween 80 as a surfactant enhanced PAH removal up to 30% of the total PAH content of the soil in 9 days. © 2011 Elsevier B.V.

  9. Test plan for preliminary study of inorganic contaminant removal from RMA groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, D.; Terkonda, P.; Weeks, N.

    1978-02-01

    This document consists of a major report on inorganic contaminant removal from ground water. In this plan, WES has been requested by the OPM-CDIR to conduct a literature review and preliminary laboratory treatability studies on various source waters at RMA. Recommendation is that the determination of suitable treatment processes be based on both engineering and economic analysis and that the processes be compatible with the organic contaminant treatment processes under study (activated carbon adsorption and ultraviolet/ozone oxidation). The amendment to the test plan presents the inorganic treatment processes found from the literature to be applicable to the inorganic contaminants in RMA ground water and outlines the bench scale study to be conducted at WES using the potential processes. The rest of the document is correspondence and reports on various water treatability.

  10. Means to remove electrode contamination effect of Langmuir probe measurement in space

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, K.-I.; Lee, C. H.; Fang, H. K.; Cheng, C. Z. [Plasma and Space Science Center, National Cheng Kung University, No.1 Ta-Hsueh Rd., Tainan 70101, Taiwan (China)

    2012-05-15

    Precaution to remove the serious effect of electrode contamination in Langmuir probe experiments has not been taken in many space measurements because the effect is either not understood or ignored. We stress here that one should pay extra attention to the electrode contamination effect to get accurate and reliable plasma measurements so that the long time effort for sounding rocket/satellite missions does not end in vain or becomes less fruitful. In this paper, we describe two main features of voltage-current characteristic curves associated with the contaminated Langmuir probe, which are predicted from the equivalent circuit model, which we proposed in 1970's. We then show that fast sweeping dc Langmuir probes can give reliable results in the steady state regime. The fast sweeping probe can also give reliable results in transient situations such as satellite moves through plasma bubble in the ionosphere where the electron density drastically changes. This fact was first confirmed in our laboratory experiment.

  11. A review on removing pharmaceutical contaminants from wastewater by constructed wetlands: design, performance and mechanism.

    Science.gov (United States)

    Li, Yifei; Zhu, Guibing; Ng, Wun Jern; Tan, Soon Keat

    2014-01-15

    This paper presents a comprehensive review of the current state of research activities on the application of constructed wetlands for removing pharmaceutical contaminants from wastewater. The focus of the review was placed on the application of constructed wetlands as an alternative secondary wastewater treatment system or as a wastewater polishing treatment system. The design parameters of the reported constructed wetlands including the physical configuration, hydraulic mode, vegetation species, and targeting pharmaceuticals were summarized. The removal efficiencies of pharmaceuticals under different conditions in the wetlands were evaluated at the macroscopic level. In addition, the importance of the three main components of constructed wetlands (substrate, plants and microbes) for pharmaceutical removal was analyzed to elucidate the possible removal mechanisms involved. There is a general consensus among many researchers that constructed wetlands hold great potential of being used as an alternative secondary wastewater treatment system or as a wastewater polishing treatment system for the removal of pharmaceuticals, but relevant reported studies are scarce and are not conclusive in their findings. Current knowledge is limited on the removal efficiencies of pharmaceuticals in constructed wetlands, the removal mechanisms involved, the toxicity to constructed wetlands caused by pharmaceuticals, and the influences of certain important parameters (configuration design, hydraulic mode, temperature and seasonality, pH, oxygen and redox potential, etc.). This review promotes further research on these issues to provide more and better convincing evidences for the function and performance of larger laboratory-scale, pilot-scale or full-scale constructed wetlands. © 2013.

  12. Contaminant Removal of Domestic Wastewater by Constructed Wetlands: Effects of Plant Species

    Institute of Scientific and Technical Information of China (English)

    Qiong Yang; Zhang-He Chen; Jian-Gang Zhao; Bin-He Gu

    2007-01-01

    A comparative study of the efficiency of contaminant removal between five emergent plant species and between vegetated and unvegetated wetlands was conducted in small-scale (2.0 m×1.0 m×0.7 m, length×width×depth) constructed wetlands for domestic wastewater treatment in order to evaluate the decontaminated effects of different wetland plants. There was generally a significant difference in the removal of total nitrogen (TN) and total phosphorus (TP), but no significant difference in the removal of organic matter between vegetated and unvegetated wetlands.Wetlands planted with Canna indica Linn., Pennisetum purpureum Schum., and Phragmites communls Trin. had generally higher removal rates for TN and TP than wetlands planted with other species. Plant growth and fine root (root diameter ≤ 3 mm) biomass were related to removal efficiency. Fine root biomass rather than the mass of the entire root system played an important role in wastewater treatment. Removal efficiency varied with season and plant growth. Wetlands vegetated by P. purpureum significantly outperformed wetlands with other plants in May and June, whereas wetlands vegetated by P. communis and C. indica demonstrated higher removal efficiency from August to December. These findings suggest that abundance of fine roots is an important factor to consider in selecting for highly effective wetland plants. It also suggested that a plant community consisting of multiple plant species with different seasonal growth patterns and root characteristics may be able to enhance wetland performance.

  13. Variable fidelity robust optimization of pulsed laser orbital debris removal under epistemic uncertainty

    Science.gov (United States)

    Hou, Liqiang; Cai, Yuanli; Liu, Jin; Hou, Chongyuan

    2016-04-01

    A variable fidelity robust optimization method for pulsed laser orbital debris removal (LODR) under uncertainty is proposed. Dempster-shafer theory of evidence (DST), which merges interval-based and probabilistic uncertainty modeling, is used in the robust optimization. The robust optimization method optimizes the performance while at the same time maximizing its belief value. A population based multi-objective optimization (MOO) algorithm based on a steepest descent like strategy with proper orthogonal decomposition (POD) is used to search robust Pareto solutions. Analytical and numerical lifetime predictors are used to evaluate the debris lifetime after the laser pulses. Trust region based fidelity management is designed to reduce the computational cost caused by the expensive model. When the solutions fall into the trust region, the analytical model is used to reduce the computational cost. The proposed robust optimization method is first tested on a set of standard problems and then applied to the removal of Iridium 33 with pulsed lasers. It will be shown that the proposed approach can identify the most robust solutions with minimum lifetime under uncertainty.

  14. Removal of heavy metals from a contaminated soil using tartaric acid

    Institute of Scientific and Technical Information of China (English)

    KE Xin; LI Pei-jun; ZHOU Qi-xing; ZHANG Yun; SUN Tie-heng

    2006-01-01

    This study reports the feasibility of remediation of a heavy metal (HM) contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinetics of HM dissolution/desorption and to predict equilibrium concentrations of HMs in soil leachate. The changes of HMs in different fractions before and after tartaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartaric acid was effective for removal of HMs from the contaminated soil, attaining 50%-60% of Cd, 40%-50% of Pb, 40%-50% of Cu and 20%-30% of Zn in the pH range of 3.5-4.0 within 24 h. Mass transfer coefficients for cadmium (Cd) and lead (Pb) were much higher than those for copper (Cu) and zinc (Zn). Sequential fractionations of treated and untreated soil samples showed that tartaric acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fraciton were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is needed before the method can be practically used for in situ remediation of contaminated sites.

  15. Filtering images contaminated with pep and salt type noise with pulse-coupled neural networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junying; LU Zhijun; SHI Lin; DONG Jiyang; SHI Meihong

    2005-01-01

    Pulse coupled neural network (PCNN) has a specific feature that the fire of one neuron can capture its adjacent neurons to fire due to their spatial proximity and intensity similarity. In this paper, it is indicated that this feature itself is a very good mechanism for image filtering when the image is damaged with pep and salt (PAS) type noise. An adaptive filtering method, in which the noisy pixels are first located and then filtered based on the output of the PCNN, is presented. The threshold function of a neuron in the PCNN is designed when it is used for filtering random PAS and extreme PAS noise contaminated image respectively. The filtered image has no distortion for noisy pixels and only less mistiness for non-noisy pixels, compared with the conventional window-based filtering method. Excellent experimental results show great effectiveness and efficiency of the proposed method, especially for heavy-noise contaminated images.

  16. Electrospun and functionalized PVDF/PAN composite for the removal of trace metals in contaminated water

    Science.gov (United States)

    Nthumbi, R. M.; Adelodun, A. A.; Ngila, J. C.

    2017-08-01

    The electrospinning of a nanofiber composite of polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN) in a dimethylformamide (DMF) solvent was carried out prior to functionalization by free radical grafting of acrylic acid (AA) brushes. Subsequent application for the removal of Pb2+ and Cd2+ from contaminated water is reported. Free radicals were initiated on the polymeric nanofiber composite using 5% 2,2‧-Azobis(2-methylpropionitrile) (AIBN) in acetone. Upon solvent removal by air-drying, AA was added and grafting (in a methanol-water solvent system) was carried out in an oil bath at 70 °C for 5 h under nitrogen atmosphere. Structural and chemical characterization of the composite was done using scanning electron microscope (SEM), nitrogen sorption at 77 K (BET method), goniometer and Fourier transform infrared spectrometer (FTIR), while changes in metal ion concentration during batch adsorption were monitored using inductively coupled plasma optical emission spectrometer (ICP-OES). Through isotherm study, the adsorption was confirmed to follow both Langmuir and Freundlich models whilst adsorption kinetic studies showed that the adsorption rate is of pseudo-second order. In furtherance, the respective values for adsorption capacity and estimated removal efficiency for Pb2+ and Cd2+ were 1.585 and 0.164 mg g-1, 90% and 80% respectively, while a 5% loss in regeneration efficiency after 10 cycles was also observed. Consequently, the nanocomposite was found efficient when applied to the removal of Pb2+ and Cd2+ from contaminated water.

  17. Removal of cadmium from cadmium-contaminated red soils using electrokinetic soil processing

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-guo; LI Cheng-feng; ZENG Guang-ming; YUE Xiu; LI Xin; XU Wei-hua; TANG Chun-fang; YUAN Xing-zhong

    2005-01-01

    To investigate the feasibility of electrokinetic soil processing on the removal of Cd from Cd-contaminated red soils, a laboratory experiment was conducted. A constant direct current density of 0.5mA/cm2 was applied. The result shows that the Cd-removal efficiency is remarkably pH-dependent, which is caused by the change of Cd retention capacity of the red soils under different pH conditions. The initial Cd concentration is 1.490g/kg and over 79% of it is removed from the red soils after treatment for 96h. The energy expenditure per unit volume at the end of experiment is about 77.6kW·h/m3 and the capital consumed by the whole experiment is 42.6RMB Yuan/m3, which suggests that the electrokinetic soil processing is a promising technology for remedying Cd-contaminated red soils due to its high removal efficiency and low energy consumption.

  18. Preparation of Silica/Reduced Graphene Oxide Nanosheet Composites for Removal of Organic Contaminants from Water.

    Science.gov (United States)

    Li, Wen; Liu, Wei; Wang, Haifei; Lu, Wensheng

    2016-06-01

    Graphene-based composites open up new opportunities as effective adsorbents for the removal of organic contaminants from water. In this article, we report a novel and facile process to synthesize well-dispersed silica/reduced graphene oxide (SiO2/RGO) nanosheet composites. The SiO2/RGO nanosheet composites are prepared through a modified sol-gel process with in situ hydrolysis of tetraethoxysilane (TEOS) on graphene oxide (GO) nanosheet, followed by reduction of GO to graphene. In comparison with the RGO nanosheets, the as-prepared SiO2/RGO nanosheet composites have a larger surface area and good aqueous disperse ability. In addition, the application of SiO2/RGO nanosheet composites was demonstrated on removing organic dyes from water. The SiO2/RGO nanosheet composites show rapid and stable adsorption performance on removal of Methylene Blue (MB) and thionine (TH) from water. It is indicated that the resulting SiO2/RGO composites can be utilized as efficient adsorbents for the removal of organic contaminants from water.

  19. Efficiency of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from contaminated soil.

    Science.gov (United States)

    Singh, Anil Kumar; Cameotra, Swaranjit Singh

    2013-10-01

    This study describes the potential application of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from the soil samples collected from industrial dumping site. High concentrations of heavy metals (like iron, lead, nickel, cadmium, copper, cobalt and zinc) and petroleum hydrocarbons were present in the contaminated soil samples. Lipopeptide biosurfactant, consisting of surfactin and fengycin was obtained from Bacillus subtilis A21. Soil washing with biosurfactant solution removed significant amount of petroleum hydrocarbon (64.5 %) and metals namely cadmium (44.2 %), cobalt (35.4 %), lead (40.3 %), nickel (32.2 %), copper (26.2 %) and zinc (32.07 %). Parameters like surfactant concentration, temperature, agitation condition and pH of the washing solution influenced the pollutant removing ability of biosurfactant mixture. Biosurfactant exhibited substantial hydrocarbon solubility above its critical micelle concentration. During washing, 50 % of biosurfactant was sorbed to the soil particles decreasing effective concentration during washing process. Biosurfactant washed soil exhibited 100 % mustard seed germination contradictory to water washed soil where no germination was observed. The results indicate that the soil washing with mixture of lipopeptide biosurfactants at concentrations above its critical micelle concentration can be an efficient and environment friendly approach for removing pollutants (petroleum hydrocarbon and heavy metals) from contaminated soil.

  20. A comparative study of hair removal at an NHS hospital: Luminette intense pulsed light versus electrolysis.

    Science.gov (United States)

    Harris, Karen; Ferguson, Janice; Hills, Samantha

    2014-04-01

    Twenty-five women, referred for hair removal by electrolysis, were enrolled in a split face study to treat facial hirsutism. Each patient was treated on six occasions: one-half of the face with electrolysis and the other side with an intense pulsed light source. Patients were evaluated with respect to reduction in hair counts, side effects and discomfort during treatment. Re-growth was assessed at 3, 6 and 9 months following treatment. All patients, except one with very sparse, fair hair growth, preferred treatment with the Intense Pulsed Light and rated their average hair reduction with this method as 77% after five treatments. The overall patient satisfaction rates as determined by visual analogue scales were 8.3 out of 10 for IPL and 5.4 out of 10 for electrolysis.

  1. Evaluation of electrochemical processes for the removal of several target aromatic hydrocarbons from petroleum contaminated water.

    Science.gov (United States)

    Alsalka, Yamen; Karabet, François; Hashem, Shahir

    2011-03-01

    Ground and surface water contamination resulting from the leakage of crude oil and refined petroleum products is a serious and growing environmental problem throughout the world. Consequently, a study of the use of electrochemical treatment in the clean-up was undertaken with the aim of reducing the water contamination by aromatic pollutants to more acceptable levels. In the experiments described, water contamination by refined petroleum products was simulated under laboratory conditions. Electrochemical treatment, using aluminium electrodes, has been optimised by full factorial design and surface response analysis in term of BTEX and PAHs removal and energy consumption. The optimal conditions of pH, current density, electrolysis time, electrolyte type, and electrolyte concentration have then been applied in the treatment of real water samples which were monitored as petroleum contaminated samples. Treatment results have shown that electrochemical methods could achieve the concentration of these pollutants to undetectable levels in particular groundwater and surface water, hence, they can be highly effective in the remediation of water contaminated by aromatic hydrocarbons, and the use of these processes is therefore recommended.

  2. Factors affecting xylene-contaminated air removal by the ornamental plant Zamioculcas zamiifolia.

    Science.gov (United States)

    Sriprapat, Wararat; Boraphech, Phattara; Thiravetyan, Paitip

    2014-02-01

    Fifteen plant species-Alternanthera bettzickiana, Drimiopsis botryoides, Aloe vera, Chlorophytum comosum, Aglaonema commutatum, Cordyline fruticosa, Philodendron martianum, Sansevieria hyacinthoides, Aglaonema rotundum, Fittonia albivenis, Muehlenbeckia platyclada, Tradescantia spathacea, Guzmania lingulata, Zamioculcas zamiifolia, and Cyperus alternifolius-were evaluated for the removal efficiency of xylene from contaminated air. Among the test plants, Z. zamiifolia showed the highest xylene removal efficiency. Xylene was toxic to Z. zamiifolia with an LC50 of 3,464 ppm. Higher concentrations of xylene exhibited damage symptoms, including leaf tips turning yellow, holonecrosis, and hydrosis. TEM images showed that a low concentration of xylene vapors caused minor changes in the chloroplast, while a high concentration caused swollen chloroplasts and damage. The effect of photosynthetic types on xylene removal efficiency suggests that a mixture of Z. zamiifolia, S. hyacinthoides, and A. commutatum which represent facultative CAM, CAM, and C3 plants, is the most suitable system for xylene removal. Therefore, for maximum improvement in removing xylene volatile compounds under various conditions, multiple species are needed. The effect of a plant's total leaf area on xylene removal indicates that at lower concentrations of xylene, a small leaf area might be as efficient as a large leaf area.

  3. Removal of tetracycline from contaminated water by Moringa oleifera seed preparations.

    Science.gov (United States)

    Santos, Andréa F S; Matos, Maria; Sousa, Ângela; Costa, Cátia; Nogueira, Regina; Teixeira, José A; Paiva, Patrícia M G; Parpot, Pier; Coelho, Luana C B B; Brito, António G

    2016-01-01

    The aim of this study was to evaluate tetracycline antibiotic (TA) removal from contaminated water by Moringa oleifera seed preparations. The composition of synthetic water approximate river natural contaminated water and TA simulated its presence as an emerging pollutant. Interactions between TA and protein preparations (extract; fraction and lectin) were also evaluated. TA was determined by solid-phase extraction followed by high-performance liquid chromatography-mass spectrometry. Moringa extract and flour removed TA from water. The extract removed TA in all concentrations, and better removal (40%) was obtained with 40 mg L(-1); seed flour (particles  5 mm (0.50 g L(-1)) removed 55% of antibiotic. Interactions between TA and seed preparations were assayed by haemagglutinating activity (HA). Specific HA (SHA) of extract (pH 7) was abolished with tetracycline (5 mg L(-1)); fraction (75%) and lectin HA (97%) were inhibited with TA. Extract SHA decreased by 75% at pH 8. Zeta potential (ZP) of extract 700 mg L(-1) and tetracycline 50 mg L(-1) , pH range 5-8, showed different results. Extract ZP was more negative (-10.73 to -16.00 mV) than tetracycline ZP (-0.27 to -20.15 mV); ZP difference was greater in pH 8. The focus of this study was achieved since Moringa preparations removed TA from water and compounds interacting with tetracycline involved at least lectin-binding sites. This is a natural process, which do not promote environmental damage.

  4. Engineering evaluation/cost analysis for the proposed removal of contaminated materials at the Elza Gate site, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1991-06-01

    This engineering evaluation/cost analysis (EE/CA) has been prepared in support of the proposed removal action for cleanup of radioactive and chemically contaminated soil at the Elza Gate site in Oak Ridge, Tennessee. This property became contaminated as a result of storage of ore residues, equipment, and other materials for the US Atomic Energy Commission. The US Department of Energy is responsible for cleanup of portions of the site under its Formerly Utilized Sites Remedial Action Program. In December 1990 an area known as Pad 1 was abrasively scoured to remove surface contamination, and in March 1991 removal of Pad 1 contamination was begun under a separate EE/CA. This EE/CA is intended to cover the remaining portions of the site for which the Department of Energy has responsibility. It has been determined that an EE/CA report is appropriate documentation for the proposed removal action. This EE/CA covers removal of contaminated soils and contaminated concrete rubble from the Elza Gate site. The primary objectives of this EE/CA report are to identify and describe the preferred removal action, and to document the selection of response activities that will mitigate the potential for release of contaminants from the property into the environment and that will minimize the associated threats to human health or welfare and the environment. The preferred alternative is disposition on the Oak Ridge Reservation. 30 refs., 7 figs., 12 tabs.

  5. Evaluation of a coagulation/flocculation-lamellar clarifier and filtration-UV-chlorination reactor for removing emerging contaminants at full-scale wastewater treatment plants in Spain.

    Science.gov (United States)

    Matamoros, Víctor; Salvadó, Victòria

    2013-03-15

    The presence and elimination of 25 emerging contaminants in two full-scale Spanish wastewater treatment plants was studied. The tertiary treatment systems consisted of coagulation, flocculation lamellar settlement and filtration (pulsed-bed sand filters) units, and disinfection was carried out by medium pressure UV light lamps and chlorination. Diclofenac and carbamazepine were found to be the emerging contaminants with the highest concentrations in secondary effluents. Photodegradable emerging contaminants (e.g. ketoprofen, triclosan and diclofenac) were removed by filtration-UV light radiation-chlorination whereas most hydrophobic compounds (e.g. galaxolide and tonalide) were eliminated by coagulation-flocculation followed by lamellar clarification, a unit in which a seasonal trend was observed. Overall mass removal efficiency was about 60%. 1-(8-Chlorocarbazolyl) acetic acid, an intermediate product of the photodegradation of diclofenac, was detected after filtration-UV-chlorination, but not after coagulation-flocculation and lamellar clarification. This study demonstrated potential for general applicability of two established tertiary treatment systems to eliminate emerging contaminants.

  6. Removal of arsenic from contaminated groundwater by solar-driven membrane distillation

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Ajay K.; Sen, Mou [Environment and Membrane Technology Laboratory, Department of Chemical Engineering, National Institute of Technology, Durgapur 713209 India (India); Martin, Andrew R. [Department of Energy Technology, The Royal Institute of Technology (KTH), Stockholm (Sweden); Pal, Parimal, E-mail: parimalpal2000@yahoo.co [Environment and Membrane Technology Laboratory, Department of Chemical Engineering, National Institute of Technology, Durgapur 713209 India (India)

    2010-03-15

    Experimental investigations were carried out on removal of arsenic from contaminated groundwater by employing a new flat-sheet cross flow membrane module fitted with a hydrophobic polyvinylidenefluoride (PVDF) microfiltration membrane. The new design of the solar-driven membrane module in direct contact membrane distillation (DCMD) configuration successfully produced almost 100 per cent arsenic-free water from contaminated groundwater in a largely fouling-free operation while permitting high fluxes under reduced temperature polarization. For a feed flow rate of 0.120 m{sup 3}/h, the 0.13 mum PVDF membrane yielded a high flux of 74 kg/(m{sup 2} h) at a feed water temperature of 40 deg. C and, 95 kg/m{sup 2} h at a feed water temperature of 60 deg. C. The encouraging results show that the design could be effectively exploited in the vast arsenic-affected rural areas of South-East Asian countries blessed with abundant sunlight particularly during the critical dry season. - Solar-driven membrane distillation has the potential of removing arsenic from contaminated groundwater.

  7. In situ electro-osmotic cleanup of tar contaminated soil—Removal of polycyclic aromatic hydrocarbons

    KAUST Repository

    Lima, Ana T.

    2012-12-01

    An in situ electro-osmosis experiment was set up in a tar contaminated clay soil in Olst, the Netherlands, at the site of a former asphalt factory. The main goal of this experiment was to remove polycyclic aromatic hydrocarbons (PAHs) from the contaminated clay layer by applying an electric gradient of 12 V m-1 across the soil over an electrode distance of 1 m. With the movement of water by electro-osmosis and the addition of a non-ionic surfactant (Tween 80), the non-polar PAHs were dragged along by convection and removed from the fine soil fraction. Soil samples were taken at the start and after 159 days at the end of the experiment. Water at the electrode wells was sampled regularly during the course of the experiment. The results reflect the heterogeneity of the soil characteristics and show the PAH concentrations within the experimental set up. After first having been released into the anolyte solution due to extraction by Tween 80 and subsequent diffusion, PAH concentrations increased significantly in the electrode reservoirs at the cathode side after 90 days of experiment. Although more detailed statistical analysis is necessary to quantify the efficiency of the remediation, it can be concluded that the use of electro-osmosis together with a non-ionic surfactant is a feasible technique to mobilize non-polar organic contaminants in clayey soils. Crown Copyright © 2011 Published by Elsevier Ltd. All rights reserved.

  8. The Retrospective Evaluation of the Efficacy and Safety of IPL (Intense Pulse Light in Hair Removal

    Directory of Open Access Journals (Sweden)

    İlgen Ertam

    2012-06-01

    Full Text Available Background and Design: There are numerous therapeutic methods for hair removal with various success rates. The aim of this study was to evaluate the efficacy of Intense Pulse Light (IPL method for hair removal.Materials and Methods: Ninety patients, who applied for their unwanted hair, were included in the study. IPL was applied to the face, neck, axillary areas, bikini line, sternal area, periareolar areas, and upper and lower extremities. An IPL device (L900 A&M, France was used for hair removal. The results were evaluated according to the clinical improvement (0-25%, 25-50%, 50-75%, 75% and more and patients? satisfaction (very satisfied, satisfied, less satisfied, not satisfied. All results were analyzed using Chi-square test and statistical analysis was performed by SPSS 15.0 for Windows. Results: There were eighty-eight female (97.8% and two male (2.2% patients. The mean age of the patients was 33.62±11.11 (15- 55 years. 13.3% of patients had polycystic ovary syndrome. The mean number of treatments was 6.5 (min-max= 2-11. 53.2% of patients had 50-75% clinical response and 53.2% of patients were satisfied. There were no side effects except mild erythema. Conclusion: We observed that IPL for hair removal was safe and moderately effective in our patients.

  9. Development of sustainable Palladium-based catalysts for removal of persistent contaminants from drinking water

    Science.gov (United States)

    Shuai, Danmeng

    Pd-based catalytic reduction has emerged as an advanced treatment technology for drinking water decontamination, and a suite of persistent contaminants including oxyanions, N-nitrosoamines, and halogenated compounds are amenable to catalytic reduction. The primary goal of this study is to develop novel Pd-based catalysts with enhanced performance (i.e., activity, selectivity, and sustainability) to remove contaminants from drinking water. The effects of water quality (i.e., co-contaminants in water matrix), catalyst support, and catalyst metal were explored, and they provide insights for preparing catalysts with faster kinetics, higher selectivity, and extended lifetime. Azo dyes are wide-spread contaminants, and they are potentially co-exisiting with target contaminants amenable for catalytic removal. The probe azo dye methyl orange (MO) enhanced catalytic reduction kinetics of a suite of oxyanions (i.e., nitrate, nitrite, bromate, chlorate, and perchlorate) and diatrizoate significantly but not N-nitrosodimethylamine (NDMA) with a variety of Pd-based catalysts. Nitrate was selected as a probe contaminant, and several different azo dyes (i.e., (methyl orange, methyl red, fast yellow AB, metanil yellow, acid orange 7, congo red, eriochrome black T, acid red 27, acid yellow 11, and acid yellow 17) were evaluated for their ability to enhance reduction. A hydrogen atom shuttling mechanism was proposed and a kinetic model was proposed based on Bronsted-Evans-Polanyi (BEP) theory, and they suggest sorbed azo dyes and reduced hydrazo dyes shuttle hydrogen atoms to oxyanions or diatrizoate to enhance their reduction kinetics. Next, vapor-grown carbon nanofiber (CNF) supports were used to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). In order to evaluate the amount of interior versus exterior loading of Pd nanoparticles, a fast and accurate geometric

  10. Biochar-supported zerovalent iron for removal of various contaminants from aqueous solutions.

    Science.gov (United States)

    Zhou, Yanmei; Gao, Bin; Zimmerman, Andrew R; Chen, Hao; Zhang, Ming; Cao, Xinde

    2014-01-01

    This work describes the synthesis and testing of a novel environmental sorbent that combines the advantages of biochar, chitosan, and zerovalent iron (ZVI). Chitosan was used as a dispersing and soldering reagent to attach fine ZVI particles onto bamboo biochar surfaces. Characterization of the resulted ZVI-biochar composites (BBCF) indicated that chitosan effectively soldered the iron particles onto carbonaceous surfaces within the biochar pore networks. The BBCF showed enhanced ability to sorb heavy metals (Pb(II), Cr(VI), and As(V)), phosphate (P), and methylene blue (MB) from aqueous solutions. The removal of Pb(II), Cr(VI), and MB by the biochar-supported ZVI was mainly controlled by both the reduction and surface adsorption mechanisms. Removal of anionic contaminants (As(V) and P) was likely controlled by electrostatic attraction with the iron particles on the BBCF surfaces. An additional benefit is that the contaminant-laden BBCF could be removed from aqueous solution easily by magnetic attraction.

  11. Biostrategic Removal of Sulphur Contamination in Groundwater With Sulphur-Reducing Bacteria: A Review

    Directory of Open Access Journals (Sweden)

    Sandeep Satapathy

    2017-02-01

    Full Text Available The rapid growth in the use of fertilizers and pesticides in agriculture, excessive extraction of groundwater, and rise in the number of industries with inefficient waste disposal system have been some of the key factors in degradation of groundwater quality during the past years. Although groundwater is considered as a valuable natural resource, the quality control of this resource has systematically failed in India. Irrespective of rural or urban locations, the average sulphate contamination of groundwater in India has reached 90 to 150 mg/L. Such a borderline contamination concentration poses threat both to livelihood and to economy. In addition, the negative health effects of sulphate-contaminated drinking water can range from dermatitis to lung problems and skin cancer. The biostrategic manipulation of groundwater discussed in this article involves sulphate-reducing bacteria used in addition to a 3-step procedure involving constitutive aeration, filtration, and shock chlorination. With earlier use of a similar strategy in the United States and Europe proven to be beneficial, we propose a combinatorial and economical approach for processing of groundwater for removal of sulphur contamination, which still largely remains unnoticed and neglected.

  12. Compost-mediated removal of polycyclic aromatic hydrocarbons from contaminated soil.

    Science.gov (United States)

    Sasek, V; Bhatt, M; Cajthaml, T; Malachová, K; Lednická, D

    2003-04-01

    Compost-assisted remediation of a manufactured-gas plant soil contaminated with polycyclic aromatic hydrocarbons (PAHs) was performed in thermally insulated composting chamber using mushroom compost consisting wheat straw, chicken manure, and gypsum. The degradation of individual PAHs was in range of 20-60% at the end of 54 days of composting followed by further increase of PAH removal (37-80%) after another 100 days of maturation. Both chemical analysis of the contaminated soil for PAHs and ecotoxicity tests on bioluminescent bacteria, earthworms, and plant seeds were performed before and after the composting. After the composting, inhibition of bioluminescence decreased, whereas no significant change in toxicity was observed for earthworm survival and seed germination. Using bacterial culture of Escherichia coli K12 genotoxicity tests were performed on samples taken from different parts of the composting pile; after the composting the decrease in genotoxicity was observed only in the sample taken from upper part of the composted pile.

  13. Application of Metal Oxide Heterostructures in Arsenic Removal from Contaminated Water

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2014-01-01

    Full Text Available It has become one of the major environmental problems for people worldwide to be exposed to high arsenic concentrations through contaminated drinking water, and even the long-term intake of small doses of arsenic has a carcinogenic effect. As an efficient and economic approach for the purification of arsenic-containing water, the adsorbents in adsorption processes have been widely studied. Among a variety of adsorbents reported, the metal oxide heterostructures with high surface area and specific affinity for arsenic adsorption from aqueous systems have demonstrated a promising performance in practical applications. This review paper aims to summarize briefly the metal oxide heterostructures in arsenic removal from contaminated water, so as to provide efficient, economic, and robust solutions for water purification.

  14. Study on Decomposition of Indoor Air Contaminants by Pulsed Atmospheric Microplasma

    Directory of Open Access Journals (Sweden)

    Tomoya Kuwabara

    2012-10-01

    Full Text Available Decomposition of formaldehyde (HCHO by a microplasma reactor in order to improve Indoor Air Quality (IAQ was achieved. HCHO was removed from air using one pass through reactor treatment (5 L/min. From an initial concentration of HCHO of 0.7 ppm about 96% was removed in one pass treatment using a discharge power of 0.3 W provided by a high voltage amplifier and a Marx Generator with MOSFET switches as pulsed power supplies. Moreover microplasma driven by the Marx Generator did not generate NOx as detected by a chemiluminescence NOx analyzer. In the case of large volume treatment the removal ratio of HCHO (initial concentration: 0.5 ppm after 60 minutes was 51% at 1.2 kV when using HV amplifier considering also a 41% natural decay ratio of HCHO. The removal ratio was 54% at 1.2 kV when a Marx Generator energized the electrodes with a 44% natural decay ratio after 60 minutes of treatment.

  15. Study on decomposition of indoor air contaminants by pulsed atmospheric microplasma.

    Science.gov (United States)

    Shimizu, Kazuo; Kuwabara, Tomoya; Blajan, Marius

    2012-10-29

    Decomposition of formaldehyde (HCHO) by a microplasma reactor in order to improve Indoor Air Quality (IAQ) was achieved. HCHO was removed from air using one pass through reactor treatment (5 L/min). From an initial concentration of HCHO of 0.7 ppm about 96% was removed in one pass treatment using a discharge power of 0.3 W provided by a high voltage amplifier and a Marx Generator with MOSFET switches as pulsed power supplies. Moreover microplasma driven by the Marx Generator did not generate NOx as detected by a chemiluminescence NOx analyzer. In the case of large volume treatment the removal ratio of HCHO (initial concentration: 0.5 ppm) after 60 minutes was 51% at 1.2 kV when using HV amplifier considering also a 41% natural decay ratio of HCHO. The removal ratio was 54% at 1.2 kV when a Marx Generator energized the electrodes with a 44% natural decay ratio after 60 minutes of treatment.

  16. Separation of heavy metals: Removal from industrial wastewaters and contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.W.; Shem, L.

    1993-01-01

    This paper reviews the applicable separation technologies relating to removal of heavy metals from solution and from soils in order to present the state-of-the-art in the field. Each technology is briefly described and typical operating conditions and technology performance are presented. Technologies described include chemical precipitation (including hydroxide, carbonate, or sulfide reagents), coagulation/flocculation, ion exchange, solvent extraction, extraction with chelating agents, complexation, electrochemical operation, cementation, membrane operations, evaporation, adsorption, solidification/stabilization, and vitrification. Several case histories are described, with a focus on waste reduction techniques and remediation of lead-contaminated soils. The paper concludes with a short discussion of important research needs in the field.

  17. Separation of heavy metals: Removal from industrial wastewaters and contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.W.; Shem, L.

    1993-03-01

    This paper reviews the applicable separation technologies relating to removal of heavy metals from solution and from soils in order to present the state-of-the-art in the field. Each technology is briefly described and typical operating conditions and technology performance are presented. Technologies described include chemical precipitation (including hydroxide, carbonate, or sulfide reagents), coagulation/flocculation, ion exchange, solvent extraction, extraction with chelating agents, complexation, electrochemical operation, cementation, membrane operations, evaporation, adsorption, solidification/stabilization, and vitrification. Several case histories are described, with a focus on waste reduction techniques and remediation of lead-contaminated soils. The paper concludes with a short discussion of important research needs in the field.

  18. An evaluation of alternative cleaning methods for removing an organic contaminant from a stainless steel part

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, J.L.

    1996-08-01

    As of December 1995, the manufacture of Freon, along with many other chlorofluorocarbons (CFCs), was prohibited by the Clean Air Act of 1990 (CAA). The ban of CFC solvents has forced manufacturers across the country to search for alternative metal cleaning techniques. The objective of this study was to develop a thorough, scientific based approach for resolving one specific manufacturer`s problem of removing organic contamination from a stainless steel part. This objective was accomplished with an approach that involved: (1) defining the problem, (2) identifying the process constraints, (3) researching alternate cleaning methods, (4) researching applicable government regulations, (5) performing a scientific evaluation and (6) drawing conclusions.

  19. An Insight into the Selection of Nano Particle for Removing Contaminants in Waste Water

    Directory of Open Access Journals (Sweden)

    Pandipriya J

    2014-04-01

    Full Text Available Waste water treatment is a major challenge in automobile industries and manufacturing sectors. In past few decades, research in waste water treatment has gained significant importance. Feasibility of nanoparticles for removing impurities is explored. However the major challenge lies in the synthesis of these nanoparticles. But with the advancements in nanotechnology, non-hazardous nanoparticles of size less than 10nm can be synthesized and morphological characteristics can also be successfully studied. Owing to their extremely smaller size, good absorption characteristics, better chemical reactivity, large surface to volume ratio, nanoparticles are highly suitable for removing metal/non-metal, organic/inorganic contaminants from water. This paper provides an extensive literature survey on the suitability of various nanoparticles for waste water treatment

  20. Blast furnace residues for arsenic removal from mining-contaminated groundwater.

    Science.gov (United States)

    Carrillo-Pedroza, Fco Raúl; Soria-Aguilar, Ma de Jesús; Martínez-Luevanos, Antonia; Narvaez-García, Víctor

    2014-01-01

    In this work, blast furnace (BF) residues were well characterized and then evaluated as an adsorbent material for arsenic removal from a mining-contaminated groundwater. The adsorption process was analysed using the theories of Freundlich and Langmuir. BF residues were found to be an effective sorbent for As (V) ions. The modelling of adsorption isotherms by empirical models shows that arsenate adsorption is fitted by the Langmuir model, suggesting a monolayer adsorption of arsenic onto adsorbents. Arsenate adsorption onto BF residue is explained by the charge density surface affinity and by the formation of Fe (II) and Fe (III) corrosion products onto BF residue particles. The results indicate that BF residues represent an attractive low-cost absorbent option for the removal of arsenic in wastewater treatment.

  1. Metal ions removal from wastewater or washing water from contaminated soil by ultrafiltration-complexation.

    Science.gov (United States)

    Molinari, Raffaele; Gallo, Saverio; Argurio, Pietro

    2004-02-01

    In the present paper a process for removal of ions from wastewater or from washing water of contaminated soil by using the weakly basic water-soluble polymer polyethylenimine (PEI) as chelating agent and the Cu(2+) ion as model in combination with an ultrafiltration process was investigated. The complexing agent was preliminarily tested to establish the best operative conditions of the process. Next, ultrafiltration tests by using five different membranes were realised to check membrane performance like flux and rejection. Finally, the possibility for recovering and recycling the polymer was tested in order to obtain an economically sustainable process. Obtained results showed that complexation conditions depends on pH: indeed, at a pH>6 PEI-Cu(2+) complexes are formed, while at pHultrafiltration process (PAUF) very interesting for metal ion removal from waters.

  2. Removal of fluoride from fluoride contaminated industrial waste water by electrolysis.

    Science.gov (United States)

    Joshi, Vijaya A; Nanoti, Madan V

    2003-01-01

    Wastewater containing fluoride are generally treated with lime or calcium salt supplemented with aluminium salts. Wastewater generated from different industries does not always behave in the same way due to the presence of interfering contaminants. A number of techniques have been developed and studied for the removal of excessive fluoride. Most of these are based on use of aluminium salt. In alum coagulation the sorption properties of product of hydrolysis of aluminium salts and capacity of fluoride for complex formation plays a very important role. These hydrolysis products of aluminium can be produced by passing direct current through aluminium electrode. The text presented in the paper deals with the various aspect of removal of fluoride by electrolysis using aluminium electrode from fluoride chemical based industrial wastewater.

  3. Microbial contamination of removable prosthodontic appliances from laboratories and impact of clinical storage.

    Science.gov (United States)

    Williams, D W; Chamary, N; Lewis, M A O; Milward, P J; McAndrew, R

    2011-08-26

    Decontamination of dental instruments has recently been the subject of considerable debate. However, little information is available on the potential bacterial colonisation of dental appliances returning from dental laboratories and their need for decontamination. This study investigated the extent and nature of microbial contamination of removable prosthodontic appliances produced at different dental laboratories and stored in two clinical teaching units (CTU 1 and CTU 2) of a dental hospital and school. Forty consecutive dental prosthodontic appliances that were being stored under varying conditions in the two clinical teaching units were selected for study; the appliances having been produced 'in-house' (hospital laboratory) or 'out-of-house' (external commercial laboratory). Two appliances, that were known to have undergone decontamination before storage, were used as controls. Swabs were taken according to a standard protocol and transferred to the microbiological laboratory with bacterial growth expressed as colony forming units (cfu) per cm(2). Microbial sampling yielded growth from 23 (58%) of the 40 appliances studied (CTU 1, n = 22; CTU 2, n = 18), with 38% of these having a high level of contamination (>42,000 cfu/cm(2)). The predominant bacteria isolated were Bacillus spp. (57%), pseudomonads (22%) and staphylococci (13%). Fungi of the genus Candida were detected in 38% of the samples. There was no significant difference in contamination of the appliances in relation to either their place of production or the CTU (p >0.05). However, the level of contamination was significantly higher (p = 0.035) for those appliances stored in plastic bag with fluid (n = 16) compared to those stored on models (n = 19). No growth was recovered from the two appliances that had undergone decontamination before storage. The research showed that appliances received from laboratories are often contaminated and therefore there is a need for routine disinfection of such items

  4. Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m.

    OpenAIRE

    Kanagawa, T; Mikami, E.

    1989-01-01

    Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day.

  5. Removal of the arsenic from contaminated groundwater with use of the new generation of MicroDrop Aqua system

    DEFF Research Database (Denmark)

    Kowalski, Krzysztof; Søgaard, Erik Gydesen

    2012-01-01

    The results from a new pilot scale plant of the MicroDrop Aqua arsenic removal technology are introduced. The technology is based on the employing of electrochemical iron dissolution and efficient aeration prior to sand filtration. The pilot treatment was used to study effectiveness of iron relea...... addition and easily to remove arsenic from contaminated groundwater....

  6. Removal of Zn from Contaminated Sediment by FeCl3 in HCl Solution

    Directory of Open Access Journals (Sweden)

    Sang-hun Lee

    2015-10-01

    Full Text Available Harbor sediments contaminated with ZnS concentrate were treated by ferric chloride in HCl solution to remove Zn. The sediments were evaluated using Tessier’s sequential extraction method to determine the different metal phase associations of Zn. Leaching tests were performed to investigate the effects of experimental factors, such as agitation speed, ferric ion concentration, temperature, and pulp density, on the removal of Zn. The sequential extraction procedure revealed that about 17.7% of Zn in the sediment was associated with soluble carbonate and oxide phases. The results of the leaching tests indicated that higher ferric concentration and temperature increased the leaching efficiencies significantly, while the agitation speed has a negligible effect on the removal of Zn. The removal ratio increased to more than 99% within 120 min of treatment at 1 kmol·m−3 HCl solution with 1 kmol·m−3 Fe3+, 10% pulp density, and 400 rpm at 90 °C. The dissolution kinetics of Zn were discussed by comparing the two shrinking core models. It was determined that the kinetic data followed the diffusion controlled model well compared to the surface chemical reaction model. The activation energies were calculated to be 76.9 kJ/mol, 69.6 kJ/mol, and 58.5 kJ/mol for 0.25 kmol·m−3, 0.5 kmol·m−3, and 1 kmol·m−3 Fe3+, respectively.

  7. An integrated bioremediation process for petroleum hydrocarbons removal and odor mitigation from contaminated marine sediment.

    Science.gov (United States)

    Zhang, Zhen; Lo, Irene M C; Yan, Dickson Y S

    2015-10-15

    This study developed a novel integrated bioremediation process for the removal of petroleum hydrocarbons and the mitigation of odor induced by reduced sulfur from contaminated marine sediment. The bioremediation process consisted of two phases. In Phase I, acetate was dosed into the sediment as co-substrate to facilitate the sulfate reduction process. Meanwhile, akaganeite (β-FeOOH) was dosed in the surface layer of the sediment to prevent S(2-) release into the overlying seawater. In Phase II, NO3(-) was injected into the sediment as an electron acceptor to facilitate the denitrification process. After 20 weeks of treatment, the sequential integration of the sulfate reduction and denitrification processes led to effective biodegradation of total petroleum hydrocarbons (TPH), in which about 72% of TPH was removed. In Phase I, the release of S(2-) was effectively controlled by the addition of akaganeite. The oxidation of S(2-) by Fe(3+) and the precipitation of S(2-) by Fe(2+) were the main mechanisms for S(2-) removal. In Phase II, the injection of NO3(-) completely inhibited the sulfate reduction process. Most of residual AVS and S(0) were removed within 4 weeks after NO3(-) injection. The 16S rRNA clone library-based analysis revealed a distinct shift of bacterial community structure in the sediment over different treatment phases. The clones affiliated with Desulfobacterales and Desulfuromonadales were the most abundant in Phase I, while the clones related to Thioalkalivibrio sulfidophilus, Thiohalomonas nitratireducens and Sulfurimonas denitrificans predominated in Phase II.

  8. Removal of arsenic from contaminated water sources by sorption onto iron-oxide-coated polymeric materials.

    Science.gov (United States)

    Katsoyiannis, Ioannis A; Zouboulis, Anastasios I

    2002-12-01

    The modification of polymeric materials (polystyrene and polyHIPE) by coating their surface with appropriate adsorbing agents (i.e. iron hydroxides) was investigated in the present work, in order to apply the modified media in the removal of inorganic arsenic anions from contaminated water sources. The method, termed adsorptive filtration, has been classified as an emerging technology in water treatment processes as it presents several advantages towards conventional technologies: the production of high amounts of toxic sludge can be avoided and it is considered as economically more efficient; whereas it has not yet been applied in full-scale treatment plants for low-level arsenic removal. The present experiments showed that both modified media were capable in removing arsenic from the aqueous stream, leading to residual concentration of this toxic metalloid element below 10 microg/L, which is the new maximum concentration limit set recently by the European Commission and imposed by the USEPA. Though, among the examined materials, polyHIPE was found to be more effective in the removal of arsenic, as far as it concerns the maximum sorptive capacity before the filtration bed reaches the respective breakthrough point.

  9. Synthesis and application of magnetic hydrogel for Cr(VI) removal from contaminated water

    KAUST Repository

    Tang, Samuel C N

    2010-11-01

    Many magnetic adsorbents reported in the literature, such as iron oxides, for Cr(VI) removal have been found effective only in low pH environments. Moreover, the application of polymeric hydrogels on heavy metal removal has been hindered by difficulties in separation by filtration. In this study, a magnetic cationic hydrogel was synthesized for Cr(VI) removal from contaminated water, making use of the advantages of magnetic adsorbents and polymeric hydrogels. The magnetic hydrogel was produced by imbedding 10-nm γ-Fe2O 3 nanoparticles into the polymeric matrix via radical polymerization. Characterization of the hydrogel was undertaken with Fourier transform infrared and vibrating sample magnetometer; swelling properties were tested and anionic adsorption capacity was evaluated. The magnetic hydrogel showed a superior Cr(VI) removal capacity compared to commercial products such as MIEX®. Cr(VI) removal was independent of solution pH. Results show that Cr(VI) removal kinetics was improved drastically by grinding the bulk hydrogel into powder form. At relevant concentrations, common water anions (e.g., Cl-, SO4 2-, PO4 3-) and natural organic matter did not exhibit significant inhibition of Cr(VI) adsorption onto the hydrogel. Results of vibrating sample magnetometer indicate that the magnetic hydrogel can be easily separated from treatment systems. Regeneration of the magnetic hydrogel can be easily achieved by washing the Cr(VI)-loaded hydrogel with 0.5 M NaCl solution, with a recovery rate of about 90% of Cr(VI). © Copyright 2010, Mary Ann Liebert, Inc. 2010.

  10. Removing Copper from Contaminated Water Using Activated Carbon Sorbent by Continuous Flow

    Directory of Open Access Journals (Sweden)

    M.H. Salmani

    2012-07-01

    Full Text Available Introduction: A major concern of human being is accumulation and toxicity of heavy metals in their body. Copper is a heavy metal ion that in concentration of 2 mg/l can cause numerous complications. Different treatment methods have been proposed for removing metals from contaminated water by researchers. Among these methods, sorption seems a better method with high removal efficiency. In this study, conditions for removal of copper ions by activated carbon sorbent were studied with continuous flow. Materials & Methods: This was a laboratory – experimental study. A 20mg/l solution of copper ions was prepared and passed through a 5 × 10 cm column with average output rate of 1.85 ml/min. Output of column was sampled every 30 minutes and the remaining amount of copper ion in each sample was measured by flame atomic absorption. Results: The empty bed volume (EBV was equal to 138 ml. The highest removal efficiency was 99.7 percent at 127 minutes. From equilibrium time, the removal efficiency was constant with time. The adsorption capacity of activated carbon was 0.25mg.g-1. The isotherm study indicated that the sorption data can be obeyed by both Langmuir and Freundlich isotherms (R2>0.95 but Langmuir model had higher agreement with this experimental data (R2= 0.988. Conclusion: The binding of ions to the sorbent in the adsorption process is extremely important. For this column 62.5 minutes after filling was appropriate, so the highest removal efficiency was obtained. Equilibrium time was dependent on the speed of influent through the column in the continuous flow. For selected column, the rate of 1.85 ml/min is a good performance.

  11. Comparative effectiveness of hand-cleansing agents for removing methicillin-resistant Staphylococcus aureus from experimentally contaminated fingertips.

    Science.gov (United States)

    Huang, Y; Oie, S; Kamiya, A

    1994-08-01

    Five subjects participated in a study of optimal conditions for removing methicillin-resistant Staphylococcus aureus from contaminated fingertips. Fingertips were contaminated experimentally and cleaned by various methods. Bacterial removal was measured as percentage and is given as mean +/- standard error of the mean. Rinsing the fingertips with tap water for 20 seconds and drying them with paper towels removed 95.2% +/- 1.6% of the contamination. Application of hand-cleansing agents to fingertips for 20 seconds, followed by a 20-second tap-water rinse and towel drying, removed bacteria as follows: povidone-iodine detergent, 99.2% +/- 0.4%; chlorhexidine detergent, 97.2% +/- 0.8%; and liquid soap, 96.1% +/- 1.1%. In a modification of the method, 80% ethyl alcohol applied to the fingertips for 20 seconds, followed by air drying for 40 seconds, removed 99.1% +/- 0.8% of the bacteria. Statistical analyses indicated that povidone-iodine and 80% ethyl alcohol were more effective than the other agents. Rinsing contaminated fingertips with tap water and towel drying them is sufficient to reduce contamination with methicillin-resistant S. aureus by 95%. Washing with povidone-iodine or 80% ethyl alcohol further reduces contamination by an additional 99%.

  12. The Use of Haz-Flote to Efficiently Remove Mercury from Contaminated Materials

    Energy Technology Data Exchange (ETDEWEB)

    Terry Brown

    2009-03-03

    There are thousands of known contaminated sites in the United Stated, including Superfund sites (1500 to 2100 sites), RCRA corrective action sites (1500 to 3500 sites), underground storage tanks (295,000 sites), U.S. Department of Defense sites (7300 sites), U.S. Department of Energy sites (4,000 sites), mining refuse piles, and numerous other hazardous metals and organic contamination sites. Only a small percentage of these sites has been cleaned up. The development of innovative technologies to handle the various clean-up problems on a national and international scale is commonplace. Many innovative technologies have been developed that can be used to effectively remediate contaminated materials. Unfortunately, many of these technologies are only effective for materials coarser than approximately 200 mesh. In addition, these technologies usually require considerable investment in equipment, and the clean-up costs of soil material are relatively high - in excess of $100 to $500 per yd{sup 3}. These costs result from the elaborate nature of the processes, the costs for power, and the chemical cost. The fine materials are disposed of or treated at considerable costs. As a result, the costs often associated with amelioration of contaminated sites are high. Western Research institute is in the process of developing an innovative soil washing technology that addresses the removal of contaminants from the fine size-fraction materials located at many of the contaminated sites. This technology has numerous advantages over the other ex-situ soil washing techniques. It requires a low capital investment, low operating costs and results in high levels of re-emplacement of the cleaned material on site. The process has the capability to clean the fine fraction (<200 mesh) of the soil resulting in a replacement of 95+% of the material back on-side, reducing the costs of disposal. The Haz-Flote{trademark} technology would expand the application of soil washing technology to heavy

  13. Contaminant Removal from Source Waters Using Cathodic Electrochemical Membrane Filtration: Mechanisms and Implications.

    Science.gov (United States)

    Zheng, Junjian; Ma, Jinxing; Wang, Zhiwei; Xu, Shaoping; Waite, T David; Wu, Zhichao

    2017-02-15

    Removal of recalcitrant anthropogenic contaminants from water calls for the development of cost-effective treatment technologies. In this work, a novel electrochemical membrane filtration (EMF) process using a conducting microfiltration membrane as the cathode has been developed and the degradation of sulphanilic acid (SA) examined. The electrochemical degradation of SA in flow-by mode followed pseudo-first-order kinetics with the degradation rate enhanced with increase in charging voltage. Hydrogen peroxide as well as oxidants such as HO(•) and Fe(IV)O(2+) were generated electrochemically with HO(•) found to be the dominant oxidant responsible for SA degradation. In addition to the anodic splitting of water, HO(•) was formed via a heterogeneous Fenton process with surface-bound Fe(II) resulting from aerobic corrosion of the steel mesh. In flow-through mode, the removal rate of SA was 13.0% greater than obtained in flow-by mode, presumably due to the better contact of the contaminant with the oxidants generated in the vicinity of the membrane surface. A variety of oxidized products including hydroquinone, p-benzoquinone, oxamic acid, maleic acid, fumaric acid, acetic acid, formic acid, and oxalic acid were identified and an electrochemical degradation pathway proposed. These findings highlight the potential of the cathodic EMF process as an effective technology for water purification.

  14. Selective Removal of Uranium from the Washing Solution of Uranium-Contaminated Soil

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Soo; Han, G. S.; Kim, G. N.; Koo, D. S.; Jeong, J. W.; Choi, J. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    This study examined selective removal methods of uranium from the waste solution by ion exchange resins or solvent extraction methods to reduce amount of the 2{sup nd} waste. Alamine-336, known as an excellent extraction reagent of uranium from the leaching solution of uranium ore, did not remove uranium from the acidic washing solution of soil. Uranyl ions in the acidic waste solution were sorbed on ampholyte resin with a high sorption efficiency, and desorbed from the resin by a washing with 0.5 M Na{sub 2}CO{sub 3} solution at 60 .deg. C. However, the uranium dissolved in the sulfuric acid solution was not sorbed onto the strong anion exchanger resins. A great amount of uranium-contaminated (U-contaminated) soil had been generated from the decommissioning of a uranium conversion plant. Our group has developed a decontamination process with washing and electrokinetic methods to decrease the amount of waste to be disposed of. However, this process generates a large amount of waste solution containing various metal ions.

  15. Biostimulation of metal-resistant microbial consortium to remove zinc from contaminated environments.

    Science.gov (United States)

    Mejias Carpio, Isis E; Franco, Diego Castillo; Zanoli Sato, Maria Inês; Sakata, Solange; Pellizari, Vivian H; Seckler Ferreira Filho, Sidney; Frigi Rodrigues, Debora

    2016-04-15

    Understanding the diversity and metal removal ability of microorganisms associated to contaminated aquatic environments is essential to develop metal remediation technologies in engineered environments. This study investigates through 16S rRNA deep sequencing the composition of a biostimulated microbial consortium obtained from the polluted Tietê River in São Paulo, Brazil. The bacterial diversity of the biostimulated consortium obtained from the contaminated water and sediment was compared to the original sample. The results of the comparative sequencing analyses showed that the biostimulated consortium and the natural environment had γ-Proteobacteria, Firmicutes, and uncultured bacteria as the major classes of microorganisms. The consortium optimum zinc removal capacity, evaluated in batch experiments, was achieved at pH=5 with equilibrium contact time of 120min, and a higher Zn-biomass affinity (KF=1.81) than most pure cultures previously investigated. Analysis of the functional groups found in the consortium demonstrated that amine, carboxyl, hydroxyl, and phosphate groups present in the consortium cells were responsible for zinc uptake. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Enhanced removal of lead from contaminated soil by polyol-based deep eutectic solvents and saponin

    Science.gov (United States)

    Mukhopadhyay, Soumyadeep; Mukherjee, Sumona; Hayyan, Adeeb; Hayyan, Maan; Hashim, Mohd Ali; Sen Gupta, Bhaskar

    2016-11-01

    Deep eutectic solvents (DESs) are a class of green solvents analogous to ionic liquids, but less costly and easier to prepare. The objective of this study is to remove lead (Pb) from a contaminated soil by using polyol based DESs mixed with a natural surfactant saponin for the first time. The DESs used in this study were prepared by mixing a quaternary ammonium salt choline chloride with polyols e.g. glycerol and ethylene glycol. A natural surfactant saponin obtained from soapnut fruit pericarp, was mixed with DESs to boost their efficiency. The DESs on their own did not perform satisfactory due to higher pH; however, they improved the performance of soapnut by up to 100%. Pb removal from contaminated soil using mixture of 40% DES-Gly and 1% saponin and mixture of 10% DES-Gly and 2% saponin were above 72% XRD and SEM studies did not detect any major corrosion in the soil texture. The environmental friendliness of both DESs and saponin and their affordable costs merit thorough investigation of their potential as soil washing agents.

  17. Controlled Contamination of Epoxy Composites with PDMS and Removal by Laser Ablation

    Science.gov (United States)

    Palmieri, Frank; Ledesma, Rodolfo; Cataldo, Daniel; Lin, Yi; Wohl, Christopher; Gupta, Mool; Connell, John

    2016-01-01

    Surface preparation is critical to the performance of adhesively bonded composites. During manufacturing, minute quantities of mold release compounds are inevitably deposited on faying surfaces and may compromise bond performance. To ensure safety, mechanical fasteners and other crack arrest features must be installed in the bondlines of primary structures, which negates some advantages of adhesively bonded construction. Laser ablation is an automated, repeatable, and scalable process with high potential for the surface preparation of metals and composites in critical applications such as primary airframe structures. In this study, laser ablation is evaluated on composite surfaces for the removal of polydimethylsiloxane (PDMS), a common mold release material. Composite panels were contaminated uniformly with PDMS film thicknesses as low as 6.0 nm as measured by variable angle spectroscopic ellipsometry. Bond performance was assessed by mechanical testing using a 250 F cure, epoxy adhesive and compared with pre-bond surface inspection results. Water contact angle, optically stimulated electron emission, and laser induced breakdown spectroscopy were used to characterize contaminated and laser ablated surfaces. The failure mode obtained from double cantilever beam tests correlated well with surface characterization data. The test results indicated that even low levels of PDMS were not completely removed by laser ablation.

  18. Hydrocarbon contamination in groundwaters: Removal by alcohol flooding. Technical completion report, 1 May 1988-30 April 1990

    Energy Technology Data Exchange (ETDEWEB)

    Farley, K.J.; Boyd, G.R.; Patwardhan, S.

    1992-05-01

    Present pump-and-treat remediation strategies employed to remove hydrocarbon contaminants that exist in groundwater as nonaqueous phase liquids (NAPLs) can displace only a fraction of the contaminant due to the trapping effects of capillary forces. These effects however are shown to be effectively eliminated by injecting alcohol solutions through the contamination zone. A laboratory column apparatus was developed to simulate NAPL contamination, free product recovery, and residual NAPL removal by alcohol flooding. Columns were packed with either glass beads or a South Carolina aquifer soil, and contaminated in preliminary experiments with benzene (a light NAPL) and in final experiments with trichloroethylene (TCE) (a dense NAPL). Proper scaling of the column was found to be critical in ensuring that the laboratory results adequately represented field-scale conditions.

  19. A Review of Removable Surface Contamination on Radioactive Materials Transportation Containers

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Jr, W. E.; Watson, E. C.; Murphy, D. W.; Harrer, B. J.; Harty, R.; Aldrich, J. M.

    1981-05-01

    This report contains the results of a study sponsored by the U.S. Nuclear Regulatory Commission (NRC) of removable surface contamination on radioactive materials transportation containers. The purpose of the study is to provide information to the NRC during their review of existing regulations. Data was obtained from both industry and literature on three major topics: 1) radiation doses, 2) economic costs, and 3) contamination frequencies. Containers for four categories of radioactive materials are considered including radiopharmaceuticals, industrial sources, nuclear fuel cycle materials, and low-level radioactive waste. Assumptions made in this study use current information to obtain realistic yet conservative estimates of radiation dose and economic costs. Collective and individual radiation doses are presented for each container category on a per container basis. Total doses, to workers and the public, are also presented for spent fuel cask and low-level waste drum decontamination. Estimates of the additional economic costs incurred by lowering current limits by factors of 10 and 100 are presented. Current contamination levels for each category of container are estimated from the data collected. The information contained in this report is designed to be useful to the NRC in preparing their recommendations for new regulations.

  20. REMOVAL OF MERCURY FROM CONTAMINATED SOILS AT THE PAVLODAR CHEMICAL PLANT.

    Energy Technology Data Exchange (ETDEWEB)

    KHRAPUNOV, V. YE.; ISAKOVA, R.A.; LEVINTOV, B.L.; KALB, P.D.; KAMBEROV, I.M.; TREBUKHOV, A.

    2004-09-25

    Soils beneath and adjacent to the Pavlodar Chemical Plant in Kazakhstan have been contaminated with elemental mercury as a result of chlor alkali processing using mercury cathode cell technology. The work described in this paper was conducted in preparation for a demonstration of a technology to remove the mercury from the contaminated soils using a vacuum assisted thermal distillation process. The process can operate at temperatures from 250-500 C and pressures of 0.13kPa-1.33kPa. Following vaporization, the mercury vapor is cooled, condensed and concentrated back to liquid elemental mercury. It will then be treated using the Sulfur Polymer Stabilization/Solidification process developed at Brookhaven National Laboratory as described in a companion paper at this conference. The overall project objectives include chemical and physical characterization of the contaminated soils, study of the influence of the soil's physical-chemical and hydro dynamical characteristics on process parameters, and laboratory testing to optimize the mercury sublimation rate when heating in vacuum. Based on these laboratory and pilot-scale data, a full-scale production process will be designed for testing. This paper describes the soil characterization. This work is being sponsored by the International Science and Technology Center.

  1. Simultaneous removal of PCDD/Fs, pentachlorophenol and mercury from contaminated soil.

    Science.gov (United States)

    Hung, Pao-Chen; Chang, Shu-Hao; Ou-Yang, Chia-Chien; Chang, Moo-Been

    2016-02-01

    Pentachlorophenol (PCP), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and mercury were simultaneously removed from heavily contaminated soil using a continuous pilot-scale thermal system (CPTS). Operating the system at 700 °C with 22 min of retention time ensured that the residual contaminants in remediated soil are lower in concentration than the soil standards of Taiwan EPA require. Both PCP and PCDD/Fs are effectively destroyed during the treatment at high temperatures in the CPTS, but significant dechlorination of PCDD/Fs is also found, resulting in lower net destruction efficiencies of TCDD/F and PeCDD/F-congeners, compared with those of highly chlorinated Hx-, Hp- and OCDD/F congeners. Moreover, 2,3,7,8-TetraCDD is significantly formed if the retention time is not long enough for total destruction. Inadequate reaction time (or retention time) even may lead to a rise in TEQ-value due to incomplete dechlorination. Mercury is significantly desorbed from contaminated soil and discharged through the exhaust. For PCP and PCDD/Fs, the exhaust discharge percentages including both the remediated soil and the exhaust are mercury rate is desorbed and discharged via the exhaust, so that the latter should be carefully cleaned via efficient air pollution control devices, whereas this contribution focuses on the conditions required for reaching adequate soil cleaning.

  2. Enhanced Stormwater Contaminant Removal and Improved Runoff Quality Using Modified Sorbents in Tree Filters

    Science.gov (United States)

    Schifman, L. A.; Kasaraneni, V.; Boving, T. B.; Oyanedel-Craver, V.

    2013-12-01

    Stormwater runoff, particularly in urban areas, contains high concentrations of pathogens that are often cited as one of the main reasons for beach closings and other water quality issues in coastal areas. Commonly found contaminants in runoff are often addressed by structural best management practices (BMP) that capture and treat the runoff before discharging it. Many BMP, such as tree filters, act as primary filtration devices that attenuate total suspended solids, nutrients, and heavy metals from runoff, but typically these BMPs are not designed to treat bacteria and have only minor petroleum hydrocarbon (PH) treatment capabilities. To address this shortcoming, the contaminant retention of an alternative sorption material was compared to expanded shale that is usually used in tree filters. Red cedar wood chips were modified with either Quaternary Ammonium Silane (QAS) or Silver Nanoparticles (AgNPs) to provide antimicrobial properties to the matrix and/or exploit their affinity to sorb PH, particularly polycyclic aromatic hydrocarbons (PAH). Results show that the wood chips exhibit the highest sorption capacity for QAS, making this material favorable for treating bacteria, while at the same time attenuating PAH by sorption processes. In the case of AgNP amendment to wood, less AgNP uptake and more desorption from the wood matrix was observed, making this amendment less favorable for bacteria deactivation. Batch experiments show that wood chips modified with QAS can remove up to 3 orders of magnitude of bacteria and retain up to 0.1 mg/g of PAH compared to shale, which has very limited bacteria deactivation (less than one order of magnitude) a PAH retention capacity of 0.04 mg/g. In this talk, the contaminant removal efficiency of the modified and unmodified materials will be discussed on the background of how these materials may find use in enhanced treatment of stormwater in tree filter BMPs.

  3. Removal of contaminants in a paper mill effluent by Azolla caroliniana

    Directory of Open Access Journals (Sweden)

    D. Sivakumar

    2015-09-01

    Full Text Available This study was focused on removal of various parameters in paper mill effluent using a method called bioremediation by Azolla caroliniana.  The experimental investigations have been carried out using Azolla caroliniana for conducting the sorption study with various dilution ratios (2, 4, 6, 8, and 10, pH (3, 4, 5, 6, 7, 8 and 9 and biomass (200, 400, 600, 800 and 1000 g. The maximum removal percentage of TDS, BOD and COD in a paper mill effluent was obtained at the optimum dilution ratio of 6, pH of 8 and biomass of 800 g. The results of this study indicated that the maximum removal percentage of TDS, BOD and COD in a paper mill effluent was 82.3 %, 88.6 % and 79.1 % respectively.  Also, the study focused on uptake of TDS, BOD and COD in paper mill effluent by Azolla caroliniana through bioaccumulation factor and translocation factor. The results of bioaccumulation factor revealed that TDS, BOD and COD in paper mill effluent were adsorbed by Azolla caroliniana.  The results of translocation factor revealed that the roots of Azolla caroliniana translocate the TDS, BOD and COD in a paper mill effluent to the shoots of Azolla caroliniana. From the results, this study concluded that bioremediation by Azolla caroliniana could be effectively used for removing TDS, BOD and COD in a paper mill effluent. This study also suggested that Azolla caroliniana may be used for removing various contaminants, not only from paper mill effluent, but also from any other industrial effluents.

  4. Uptake of toluene and ethylbenzene by plants: removal of volatile indoor air contaminants.

    Science.gov (United States)

    Sriprapat, Wararat; Suksabye, Parinda; Areephak, Sirintip; Klantup, Polawat; Waraha, Atcharaphan; Sawattan, Anuchit; Thiravetyan, Paitip

    2014-04-01

    Air borne uptake of toluene and ethylbenzene by twelve plant species was examined. Of the twelve plant species examined, the highest toluene removal was found in Sansevieria trifasciata, while the ethylbenzene removal from air was with Chlorophytum comosum. Toluene and ethylbenzene can penetrate the plant׳s cuticle. However, the removal rates do not appear to be correlated with numbers of stomata per plant. It was found that wax of S. trifasciata and Sansevieria hyacinthoides had greater absorption of toluene and ethylbenzene, and it contained high hexadecanoic acid. Hexadecanoic acid might be involved in toluene and ethylbenzene adsorption by cuticles wax of plants. Chlorophyll fluorescence analysis or the potential quantum yield of PSII (Fv/Fm) in toluene exposed plants showed no significant differences between the control and the treated plants, whereas plants exposed to ethylbenzene showed significant differences or those parameters, specifically in Dracaena deremensis (Lemon lime), Dracaena sanderiana, Kalanchoe blossfeldiana, and Cordyline fruticosa. The Fv/Fm ratio can give insight into the ability of plants to tolerate (indoor) air pollution by volatile organic chemicals (VOC). This index can be used for identification of suitable plants for treating/sequestering VOCs in contaminated air.

  5. Soil treatment to remove uranium and related mixed radioactive contaminants. Final report September 1992--October 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    A research and development project to remove uranium and related radioactive contaminants from soil by an ultrasonically-aided chemical leaching process began in 1993. The project objective was to develop and design, on the basis of bench-scale and pilot-scale experimental studies, a cost-effective soil decontamination process to produce a treated soil containing less than 35 pCi/g. The project, to cover a period of about thirty months, was designed to include bench-scale and pilot-scale studies to remove primarily uranium from the Incinerator Area soil, at Fernald, Ohio, as well as strontium-90, cobalt-60 and cesium-137 from a Chalk River soil, at the Chalk River Laboratories, Ontario. The project goal was to develop, design and cost estimate, on the basis of bench-scale and pilot-scale ex-situ soil treatment studies, a process to remove radionuclides form the soils to a residual level of 35 pCi/g of soil or less, and to provide a dischargeable water effluent as a result of soil leaching and a concentrate that can be recovered for reuse or solidified as a waste for disposal. In addition, a supplementary goal was to test the effectiveness of in-situ soil treatment through a field study using the Chalk River soil.

  6. Demolition and removal of radioactively contaminated concrete soil: Aerosol control and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Newton, G.J.; Hoover, M.D.; Grace, A.C. III

    1995-12-01

    From 1963 to 1985, two concrete-lined ponds were used to reduce the volume of radioactive liquids from the Institute`s research programs. Following withdrawal of the {open_quotes}hot ponds{close_quotes} from active use, the residual sludges and plastic liners of the ponds were removed and shipped to a radioactive waste disposal site. From 1987 to 1994, the concrete structures remained undisturbed pending environmental restoration on the site. Restoration began in 1994 and was completed in 1995. Restoration involved mechanical breakup and removal of the concrete structures and removal of areas of contaminated soils from the site. This report describes the design and results of the aerosol control and monitoring program that was conducted to ensure protection of workers and the environment during the restoration process. The aerosol control and monitoring strategy developed for remediation of the ITRI hot ponds was successful both in preventing dispersion of radioactive dusts and in demonstrating that exposures of workers and offsite releases were within statutory limits.

  7. Effects of effluent organic matter (EfOM) on the removal of emerging contaminants by ozonation.

    Science.gov (United States)

    Cai, Ming-Jhih; Lin, Yi-Pin

    2016-05-01

    Removal of emerging contaminants in wastewater treatment is essential to ensure the ecological health of the receiving water bodies. Ozonation is a promising technology to achieve this purpose but important wastewater characteristics affecting the optimal removal efficiency need to be elucidated. Secondary effluents contain effluent organic matter (EfOM), which can react directly with ozone as well as react as the initiator, promoter and inhibitor in the hydroxyl radical (.OH) chain reactions resulting from ozone decomposition. These different reaction modes of EfOM, coupled with alkalinity and pH value, collectively determine the ozone and .OH exposures and the degradation of pharmaceutical compounds by ozonation. In this study, we determined the rate constants of EfOM collected from two municipal wastewater treatment plants in terms of direct ozone reaction, initiation, promotion and inhibition at various pH values (pH 6.0-7.5) and temperatures (10-30 °C). The rate constants of direct reaction and initiation generally increased with the increasing pH value while the rate constants of promotion and inhibition did not vary significantly. All rate constants increased with the increasing temperature. The removal of ibuprofen, acetylsulfamethoxazole and metoprolol in diluted secondary effluent by ozonation can be fairly-well modeled by using the determined rate constants of EfOM.

  8. Selective removal of diclofenac from contaminated water using molecularly imprinted polymer microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Dai Chaomeng [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Department of Environmental Technology, Chair of Environmental Process Engineering, Technical University of Berlin, Berlin (Germany); Geissen, Sven-Uwe, E-mail: sven.geissen@tu-berlin.de [Department of Environmental Technology, Chair of Environmental Process Engineering, Technical University of Berlin, Berlin (Germany); Zhang Yalei, E-mail: zhangyalei@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Zhang Yongjun [Department of Environmental Technology, Chair of Environmental Process Engineering, Technical University of Berlin, Berlin (Germany); Zhou Xuefei [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

    2011-06-15

    A molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP were evaluated using equilibrium binding experiments. Compared to the non-imprinted polymer (NIP), the MIP showed an outstanding affinity towards DFC in an aqueous solution with a binding site capacity (Q{sub max}) of 324.8 mg/g and a dissociation constant (K{sub d}) of 3.99 mg/L. The feasibility of removing DFC from natural water by the MIP was demonstrated by using river water spiked with DFC. Effects of pH and humic acid on the selectivity and adsorption capacity of MIP were evaluated in detail. MIP had better selectivity and higher adsorption efficiency for DFC as compared to that of powdered activated carbon (PAC). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance, which is a definite advantage over single-use activated carbon. - Highlights: > A MIP was synthesized by precipitation polymerization using DFC as template. > The MIP had better selectivity and higher adsorption efficiency for DFC. > The MIP is an effective method for selective removal of DFC from complex water. > MIP reusability is a definite advantage over single-use activated carbon. - A diclofenac molecularly imprinted polymer synthesized by precipitation polymerization was used for the selective removal of diclofenac from contaminated water.

  9. Comparative Studies on Methane Upgradation of Biogas by Removing of Contaminant Gases Using Combined Chemical Methods

    Directory of Open Access Journals (Sweden)

    Muhammad Rashed Al Mamun

    2015-07-01

    Full Text Available Biogas, which generated from renewable sources can be used as a sustainable energy to achieve resourceful targets of biofuel for internal combustion engines. This process can be achieved in combined absorption and adsorption chemical way. This method can be employed by aqueous solutions of calcium hydroxide, activated carbon, iron(II chloride, silica gel and sodium sulfate respectively. The presence of CO2, H2S and H2O in the biogas has lowering the calorific value and detrimental corrosion effects on the metal components. Removal of these contaminants from the biogas can therefore significantly improve the gas quality. A comparison study was investigated using combined chemical methods of improving the calorific value of biogas. Experiment results revealed that the aqueous solution used effectively in reacting with CO2 in biogas (over 85-90% removal efficiency, creating CH4 enriched biogas. The removal efficiency was the highest in method 1, where efficiency results were 91.5%, 97.1% and 91.8%, for CO2, H2S, and H2O, respectively. The corresponding CH4 enrichment was 97.5%. These results indicate that the method 1 is more suitable compare to method 2. However, both methane enrichment processes might be useful for cleaning and upgrading methane quality in biogas.

  10. Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Sanjay, H.G.; Srivastave, K.C.; Walia, D.S. [ARCTECH, Inc., Chantilly, VA (United States)

    1995-10-01

    Heavy metal and organic contamination of surface and groundwater systems is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. The presence of toxic heavy metal ions, volatile organic compounds (VOCs) and pesticides in water is of great concern and could affect the safety of drinking water. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state of the art technologies for treatment of contaminated water however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals (ion exchange). This would require the use of at a minimum, two different stepwise processes to remediate a site. The groundwater contamination at different Department of Energy (DOE) sites (e.g., Hanford) is due to the presence of both VOCs and heavy metals. The two-step approach increases the cost of remediation. To overcome the sequential treatment of contaminated streams to remove both organics and metals, a novel material having properties to remove both classes of contaminants in one step is being developed as part of this project.The objective of this project is to develop a lignite-derived adsorbent, Humasorb{sup TM} to remove heavy metals and organics from ground water and surface water streams.

  11. CONTAMINATED PROCESS EQUIPMENT REMOVAL FOR THE D&D OF THE 232-Z CONTAMINATED WASTE RECOVERY PROCESS FACILITY AT THE PLUTONIUM FINISHING PLANT (PFP)

    Energy Technology Data Exchange (ETDEWEB)

    HOPKINS, A.M.; MINETTE, M.J.; KLOS, D.B.

    2007-01-25

    This paper describes the unique challenges encountered and subsequent resolutions to accomplish the deactivation and decontamination of a plutonium ash contaminated building. The 232-Z Contaminated Waste Recovery Process Facility at the Plutonium Finishing Plant was used to recover plutonium from process wastes such as rags, gloves, containers and other items by incinerating the items and dissolving the resulting ash. The incineration process resulted in a light-weight plutonium ash residue that was highly mobile in air. This light-weight ash coated the incinerator's process equipment, which included gloveboxes, blowers, filters, furnaces, ducts, and filter boxes. Significant airborne contamination (over 1 million derived air concentration hours [DAC]) was found in the scrubber cell of the facility. Over 1300 grams of plutonium held up in the process equipment and attached to the walls had to be removed, packaged and disposed. This ash had to be removed before demolition of the building could take place.

  12. Pulsed redistribution of a contaminant following forest fire: cesium-137 in runoff.

    Science.gov (United States)

    Johansen, Mathew P; Hakonson, Thomas E; Whicker, F Ward; Breshears, David D

    2003-01-01

    Of the natural processes that concentrate dispersed environmental contaminants, landscape fire stands out as having potential to rapidly concentrate contaminants and accelerate their redistribution. This study used rainfall simulation methods to quantify changes in concentration of a widely dispersed environmental contaminant (global fallout 137Cs) in soils and surface water runoff following a major forest fire at Los Alamos, New Mexico, USA. The 137Cs concentrations at the ground surface increased up to 40 times higher in ash deposits and three times higher for the topmost 50 mm of soil compared with pre-fire soils. Average redistribution rates were about one order of magnitude greater for burned plots, 5.96 KBq ha(-1) mm(-1) rainfall, compared with unburned plots, 0.55 KBq ha(-1) mm(-1) rainfall. The greatest surface water transport of 137Cs, 11.6 KBq ha(-1) mm(-1), occurred at the plot with the greatest amount of ground cover removal (80% bare soil) following fire. Concentration increases of 137Cs occurred during surface water erosion, resulting in enrichment of 137Cs levels in sediments by factors of 1.4 to 2.9 compared with parent soils. The elevated concentrations in runoff declined rapidly with time and cumulative precipitation occurrence and approached pre-fire levels after approximately 240 mm of rainfall. Our results provide evidence of order-of-magnitude concentration increases of a fallout radionuclide as a result of forest fire and rapid transport of radionuclides following fire that may have important implications for a wide range of geophysical, ecosystem, fire management, and risk-based issues.

  13. Anaerobic Removal of Trace Organic Contaminants in Sewage Sludge: 15 Years of Experience

    Institute of Scientific and Technical Information of China (English)

    M. BARRET; L. DELGADILLO-MIRQUEZ; E. TRABLY; N. DELGENES; F. BRAUN; G. CEA-BARCIA; J. P. STEYER; D. PATUREAU

    2012-01-01

    Trace organic contaminants (TOCs) correspond to a broad range of molecules generated either directly or indirectly by human activity.Even though TOCs are found at low concentrations in the environment,they often accumulate by biomagnification and bioaccumulation into biological organisms and cause irreversible damages in biological systems through direct or indirect toxic effects such as endocrine disruption and tumour initiation.This manuscript presents the main findings of over fifteen years of research focusing on biological removal of various TOCs found in sewage sludge from urban treatment plants.A special focus of the research was made on microbial processes in complex anaerobic ecosystems.Four families of compounds mostly retrieved in urban plants were studied:the polycyclic aromatic hydrocarbons (PAHs),the polychlorobiphenyls (PCBs),the phthalic acid esters (PAEs),and the nonylphenol ethoxylates (NPEs).It was observed that the microbial capability for removing low amounts of TOCs required a long adaptation time and was often limited by the bioavailability of these compounds.In fact,the overall biodegradation resulted from the numerous interactions existing between the matrix (organic matter) and the microbial ecosystems according to the physico-chemical sorption properties of these compounds.Mechanistic aspects were also tackled in depth and specific models were developed for better understanding the network of interactions between TOCs,microorganisms,and organic matter.These findings could be extrapolated to other ecosystems such as soils and sediments.Finally,it was shown that microbial cometabolism was essential for TOC removal,and the concept of bioavailability was not only dependent on the nature,the level,and the sorption properties of TOCs but was alsostrongly dependent on the nature and the concentration of the sludge organic matter.Specific parameters were proposed for better evaluating the fate of TOCs in microbial anaerobic processes and

  14. Removal of Anthracene and Fluoranthene by Waxy Corn, Long Bean and Okra in Lead-Contaminated Soil.

    Science.gov (United States)

    Somtrakoon, Khanitta; Chouychai, Waraporn; Lee, Hung

    2015-09-01

    The ability of waxy corn, long bean and okra to remove two polycyclic aromatic hydrocarbons (PAHs) from soil containing 0.63 mg Pb kg(-1) dry soil was assessed. The presence of Pb did not reduce the ability of these plants to remove the PAHs from soil. About 49 % of anthracene and 77 % of fluoranthene were removed from Pb-spiked or non-spiked soil, respectively, after 30 days. Among the plants, okra was the most efficient at removing anthracene and fluoranthene in the presence or absence of Pb in soil after 30 days. Pb did not affect fluoranthene removal, but stimulated the removal of anthracene, by long bean, waxy corn and okra. However, growth of long bean and waxy corn was poor in Pb-spiked soil and waxy corn plants died around 22 days after transplantation. The results show some promise in using plants to remove PAHs from soil which is also co-contaminated with Pb.

  15. Removal of Airborne Contaminants from a Surface Tank by a Push-Pull System

    DEFF Research Database (Denmark)

    Heiselberg, Per; Topp, Claus

    Open surface tanks are used in many industrial processes, and local exhaust systems are often designed to capture and remove toxic fumes diffused from materials in the tanks prior to their escape into the workplace environment. The push-pull system seems to be the most efficient local exhaust...... system, but proper design is required to ensure health and safety of the workers and, furthermore, it is very desirable from an energy conservation point of view to determine an optimum and -an efficient design of push-pull hoods which can exhaust all contaminants with a minimum quantity of volume flow....... The paper describes and discusses different design methods and compares designed values with results from a measurement series of push-pull system efficiency....

  16. Effect Of Gas Mixture Composition On Tar Removal Process In A Pulsed Corona Discharge Reactor

    Science.gov (United States)

    Filimonova E.; Naidis, G.

    2010-07-01

    The simulation of naphthalene (C10H8) removal from several gas mixtures (pure nitrogen, mixtures containing N2 with CO2, CO, H2, H2O, and biogas - the product of biomass gasification), has been investigated. The modeling is based on the experimental data obtained in the reactor with a pulsed positive corona discharge. The problem of simulation of the cleaning process includes description of two stages. The first, fast stage is generation of primary active species during streamer propagation. The second, slow stage is the chain of chemical transformations triggered by these species. The input parameters for the modeling of the second stage are G-values for generation of primary active species, obtained under consideration of streamer dynamics. Simulation of the second stage of the removal process takes into account the processes of chemical kinetics and diffusion outside and inside of streamer traces during multi-pulsed treatment. Besides neutral active species, streamer discharges produce electrons and ions. Primary positive ions (N2+, CO+, CO2+, H2+, H2O+) in a chain of fast ion-molecule reactions transform into more stable positive ions. The ions recombine with electrons. Both ion-molecule reactions and electron-ion recombination process are additional (to dissociation of gas molecules by electron impact in the streamer head) sources of neutral active species. The relative contribution of these sources to the G-values for H, OH and O is rather large. In our modeling two approaches have been used. At the first approach the contribution of ion-molecule reactions is estimated approximately assuming that the dominating stable ion is N4+ (in pure N2 and its mixtures with H2) or CO2+ (in mixtures including CO2). Other way is the calculations with kinetic scheme including the molecular ions, aquated ions such as H3O(H2O)m+, NO2(H2O)-, NO2(H2O)+ and other. The comparison of results of two approaches is presented. Only full kinetic scheme allowed describing the

  17. Removal of Ni and Zn in contaminated neutral drainage by raw and modified wood ash.

    Science.gov (United States)

    Calugaru, Iuliana L; Neculita, Carmen Mihaela; Genty, Thomas; Bussière, Bruno; Potvin, Robin

    2017-01-28

    In the present study, wood ash was modified by alkaline fusion, prior to hydrothermal synthesis, for potential application in the treatment of mine drainage impacted water. With this objective, two types of wood ash (both raw and modified) were evaluated for the treatment of Ni and Zn in contaminated neutral drainage (CND). Batch adsorption experiments were initially conducted on synthetic CND, and then on two real CND, sampled on two active mine sites, contaminated by either Ni (3.7 mg/L) or Zn (9.1 mg/L). Leaching of Zn was observed during the kinetic tests for the raw wood ash, whereas its modification suppressed the leaching. The cation exchange capacity acquired by modification of the two samples of wood ash exceeded 300 meq/100 g (which is two to fourfold higher than those of the raw ash), while sorption capacity for Ni and Zn tripled relative to the raw material. The Langmuir model best described the sorption process for all materials, while potential mechanisms of metal removal include adsorption, precipitation and ion exchange, following pseudo second-order kinetics. Results also showed that within 2 h of contact of mine effluents with one modified wood ash, Ni and Zn concentrations decreased below the maximum authorized monthly mean concentration allowed by the Canadian law (0.5 mg/L), whereas the other modified wood ash allowed reaching the regulatory conformity after 2 h for Ni but 7 days for Zn (although 93% removed after 2 h). Nonetheless, the pH was raised (10.9-11.8) above the legally allowed limits (6-9.5). Based on these findings, modified wood ash could be considered as a promising option for the treatment of Ni and Zn in CND, but the pH correction of final effluent might be necessary.

  18. Pyrene Removal from Contaminated Soils by Modified Fenton Oxidation Using Iron Nano Particles

    Directory of Open Access Journals (Sweden)

    Sahand Jorfi

    2013-07-01

    Full Text Available Background:The problems related to conventional Fenton oxidation, including low pH required and production of considerable amounts of sludge have led researchers to investigate chelating agents which might improve the operating range of pH and the use of nano iron particle to reduce the excess sludge. The pyrene removal from contaminated soils by modified Fenton oxidation at neutral pH was defined as the main objective of the current study.Methods:Varying concentrations of H2O2 (0-500 mM and iron nano oxide (0-60 mM, reaction times of 0.5-24 hours and variety of chelating agents including sodium pyrophosphate, sodium citrate, ethylene diamine tetraacetic, fulvic and humic acid were all investigated at pyrene concentration levels of 100 – 500 mg/kg.Results:By applying the following conditions (H2O2 concentration of 300 mM, iron nano oxide of 30 mM, sodium pyrophosphate as chelating agent, pH 3 and reaction time of 6 hours the pyrene removal efficiency at an initial concentration of 100 mg/kg was found to be 99%. As a result, the pyrene concentration was reduced from 100 to 93 mg/kg once the above optimum conditions are met.Conclusions:In this research, the modified Fenton oxidation using iron nano oxide at optimum conditions is introduced as an efficient alternative method in lab scale for chemical remediation or pre-treatment of soils contaminated by pyrene at neutral pH.

  19. Genesis Solar Wind Sample 61422: Experiment in Variation of Sequence of Cleaning Solvent for Removing Carbon-Bearing Contamination

    Science.gov (United States)

    Allton, J. H.; Kuhlman, K. R.; Allums, K. K.; Gonzalez, C. P.; Jurewicz, A. J. G.; Burnett, D. S.; Woolum, D. S.

    2015-01-01

    The recovered Genesis collector fragments are heavily contaminated with crash-derived particulate debris. However, megasonic treatment with ultra-pure-water (UPW; resistivity (is) greater than18 meg-ohm-cm) removes essentially all particulate contamination greater than 5 microns in size [e.g.1] and is thus of considerable importance. Optical imaging of Si sample 60336 revealed the presence of a large C-rich particle after UPW treatment that was not present prior to UPW. Such handling contamination is occasionally observed, but such contaminants are normally easily removed by UPW cleaning. The 60336 particle was exceptional in that, surprisingly, it was not removed by additional UPW or by hot xylene or by aqua regia treatment. It was eventually removed by treatment with NH3-H2O2. Our best interpretation of the origin of the 60336 particle was that it was adhesive from the Post-It notes used to stabilize samples for transport from Utah after the hard landing. It is possible that the insoluble nature of the 60336 particle comes from interaction of the Post-It adhesive with UPW. An occasional bit of Post-It adhesive is not a major concern, but C particulate contamination also occurs from the heat shield of the Sample Return Capsule (SRC) and this is mixed with inorganic contamination from the SRC and the Utah landing site. If UPW exposure also produced an insoluble residue from SRC C, this would be a major problem in chemical treatments to produce clean surfaces for analysis. This paper reports experiments to test whether particulate contamination was removed more easily if UPW treatment was not used.

  20. Simultaneous Removal of MTBE and Benzene from Contaminated Groundwater Using Ultraviolet-Based Ozone and Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Bassam S. Tawabini

    2014-01-01

    Full Text Available Efficiency of ultraviolet-ozone (UV/O3 and ultraviolet-hydrogen peroxide (UV/H2O2 processes was investigated for simultaneous removal of methyl tertiary butyl ether (MTBE and benzene from contaminated ground water. The photoreactor employed housed 15-watt low pressure (LP and 150-watt medium pressure (MP mercury UV lamps. Oxidation of contaminants was studied at two different levels of ozone and hydrogen peroxide. Brackish groundwater samples were spiked with MTBE and benzene up to a concentration of 500 μg L−1. Removal potential was evaluated at different parameters such as UV type and intensity and peroxide and ozone dosages, as well as contact time. Results indicated that no removal of the contaminants was attained when treated with hydrogen peroxide or ozone alone. However, about 50% and 30% removal of MTBE were achieved in 30 minutes when irradiated with MP-UV and LP-UV lamps, respectively. On the other hand, UV/H2O2 process was found to be superior in removal of MTBE (90% in 10 min. and benzene (95% in 5 min. compared to UV/O3 process. Furthermore, removal of benzene was comparatively easier than MTBE in both approaches. It is hence concluded that higher UV intensities and elevated doses of H2O2 accelerate simultaneous removal of MTBE and benzene from water.

  1. Removal of contaminants from equipment and debris and waste minimization using TechXtract{reg_sign} technology

    Energy Technology Data Exchange (ETDEWEB)

    Bonem, M.W. [EET, Inc., Bellaire, TX (United States)

    1997-10-01

    Under this Program Research and Development Agreement (PRDA), EET, Inc., is extending its proprietary TechXtract{reg_sign} chemical decontamination technology into an effective, economical, integrated contaminant removal system. This integrated system will consist of a series of decontamination baths using the TechXtract{reg_sign} chemical formulas, followed by a waste treatment process that will remove the contaminants from the spent chemicals. Sufficient decontamination will result so that materials can be released without restriction after they have been treated, even those materials that have traditionally been considered to be {open_quotes}undecontaminable.{close_quotes} The secondary liquid waste will then be treated to separate any hazardous and radioactive contaminants, so that the spent chemicals and wastewater can be discharged through conventional, permitted outlets. The TechXtract{reg_sign} technology is a unique process that chemically extracts hazardous contaminants from the surface and substrate of concrete, steel, and other solid materials. This technology has been used successfully to remove contaminants as varied as PCBs, radionuclides, heavy metals, and hazardous organics. The process` advantage over other alternatives is its effectiveness in safe and consistent extraction of subsurface contamination. TechXtract{reg_sign} is a proprietary process developed, owned, and provided by EET, Inc. The objective of the PRDA is to demonstrate on a full-scale basis an economical system for decontaminating equipment and debris, with further treatment of secondary waste streams to minimize waste volumes. Contaminants will be removed from the contaminated items to levels where they can be released for unrestricted use. The entire system will be designed with maximum flexibility and automation in mind.

  2. Removal of carbon contaminations by RF plasma generated reactive species and subsequent effects on optical surface

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, P. K., E-mail: praveenyadav@rrcat.gov.in; Rai, S. K.; Modi, M. H.; Nayak, M.; Lodha, G. S. [Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India); Kumar, M.; Chakera, J. A.; Naik, P. A. [Laser Plasma Laboratory, Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

    2015-06-24

    Carbon contamination on optical elements is a serious issue in synchrotron beam lines for several decades. The basic mechanism of carbon deposition on optics and cleaning strategies are not fully understood. Carbon growth mechanism and optimized cleaning procedures are worldwide under development stage. Optimized RF plasma cleaning is considered an active remedy for the same. In present study carbon contaminated optical test surfaces (carbon capped tungsten thin film) are exposed for 30 minutes to four different gases, rf plasma at constant power and constant dynamic pressure. Structural characterization (thickness, roughness and density) of virgin samples and plasma exposed samples was done by soft x-ray (λ=80 Å) reflectivity measurements at Indus-1 reflectivity beam line. Different gas plasma removes carbon with different rate (0.4 to 0.65 nm /min). A thin layer 2 to 9 nm of different roughness and density is observed at the top surface of tungsten film. Ar gas plasma is found more suitable for cleaning of tungsten surface.

  3. Molybdenum Availability Is Key to Nitrate Removal in Contaminated Groundwater Environments.

    Science.gov (United States)

    Thorgersen, Michael P; Lancaster, W Andrew; Vaccaro, Brian J; Poole, Farris L; Rocha, Andrea M; Mehlhorn, Tonia; Pettenato, Angelica; Ray, Jayashree; Waters, R Jordan; Melnyk, Ryan A; Chakraborty, Romy; Hazen, Terry C; Deutschbauer, Adam M; Arkin, Adam P; Adams, Michael W W

    2015-08-01

    The concentrations of molybdenum (Mo) and 25 other metals were measured in groundwater samples from 80 wells on the Oak Ridge Reservation (ORR) (Oak Ridge, TN), many of which are contaminated with nitrate, as well as uranium and various other metals. The concentrations of nitrate and uranium were in the ranges of 0.1 μM to 230 mM and nitrate reduction branch of the global nitrogen cycle. It is required at the catalytic site of nitrate reductase, the enzyme that reduces nitrate to nitrite. Moreover, more than 85% of the groundwater samples contained less than 10 nM Mo, whereas concentrations of 10 to 100 nM Mo were required for efficient growth by nitrate reduction for two Pseudomonas strains isolated from ORR wells and by a model denitrifier, Pseudomonas stutzeri RCH2. Higher concentrations of Mo tended to inhibit the growth of these strains due to the accumulation of toxic concentrations of nitrite, and this effect was exacerbated at high nitrate concentrations. The relevance of these results to a Mo-based nitrate removal strategy and the potential community-driving role that Mo plays in contaminated environments are discussed.

  4. Hexavalent chromium removal in contaminated water using reticulated chitosan micro/nanoparticles from seafood processing wastes.

    Science.gov (United States)

    Dima, Jimena Bernadette; Sequeiros, Cynthia; Zaritzky, Noemi E

    2015-12-01

    Chitosan particles (CH) were obtained from seafood processing wastes (shrimp shells) and physicochemically characterized; deacetylation degree of CH was measured by Infrared Spectroscopy (FTIR) and potentiometric titration; polymer molecular weight was determined by intrinsic viscosity measurements. Reticulated micro/nanoparticles of chitosan (MCH) with an average diameter close to 100nm were synthesized by ionic gelation of chitosan using tripolyphosphate (TPP), and characterized by SEM, size distribution and Zeta-potential. Detoxification capacities of CH and MCH were tested analyzing the removal of hexavalent chromium Cr(VI) from contaminated water, at different initial chromium concentrations. The effect of pH on adsorption capacity of CH and MCH was experimentally determined and analyzed considering the Cr(VI) stable complexes (anions) formed, the presence of protonated groups in chitosan particles and the addition of the reticulating agent (TPP). Chitosan crosslinking was necessary to adsorb Cr(VI) at pHremoved from the solution was reduced and bound to the MCH as Cr(III). The reduction of toxic Cr(VI) to the less or nontoxic Cr(III) by the reticulated chitosan micro/nanoparticles can be considered a very efficient detoxification technique for the treatment of Cr(VI) contaminated water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Electrokinetic removal of chromium and copper from contaminated soils by lactic acid enhancement in the catholyte

    Institute of Scientific and Technical Information of China (English)

    ZHOU Dong-mei; Alshawabkeh Akram N; DENG Chang-fen; CANG Long; SI You-bin

    2004-01-01

    The electrokinetic removal of chromium and copper from contaminated soils by adding lactic acid in cathode chamber as an enhancing reagent was evaluated. Two sets of duplicate experiments with chromium contaminated kaolinite and with a silty soil sampled from a superfund site in California of USA and polluted by Cr and Cu, were carried out in a constant current mode. Changes of soil water content and soil pH before and after the electrokinetic experiments, and variations of voltage drop and electroosmosis flow during the treatments were examined. The results indicated that Cr, spiked as Cr(Ⅵ) in the kaolinite, was accumulated mainly in the anode chamber, and some of Cr and metal hydroxides precipitated in the soil sections in contact with the cathode, which significantly increased electrical energy consumption. Treatment of the soil collected from the site showed accumulation of large amounts of Cr and Cu in the anode chamber while none was detected in the cathode one. The results suggested that the two metals either complexed with the injected lactic acid at the cathode or existed as negatively charged complex, and electromigrated toward the anode under a voltage gradient.

  6. Removal of prioritary pesticides contamining r'mel ground water by using organic waste residues.

    Science.gov (United States)

    El Bakouri, H; Morillo, J; Usero, J; Ouassini, A

    2007-01-01

    This study evaluated pesticide contamination of R'mel ground water located in northwest Morocco. The study area is densely populated and thriving, with intensive agriculture. Various techniques, including stir bar sorptive extraction (SBSE) and gas chromatography with mass spectroscopy detection (GC-MS), were used for the quantitative determination of 13 pesticides including alachlor, aldrin, atrazine, chlorpyrifos, chlorfenvinphos, dieldrin, alpha-endosulfan, endrin, hexachlorobenzene, beta-HCH, gamma-HCH (lindane), simazine and trifluralin. The survey results showed that contamination by pesticide residues is widespread in the area. With the exception of atrazine, the average concentrations were all below the regulatory limits established by the European Union. The potential of ten natural organic substances to eliminate pesticides included in the European Water Framework Directive was evaluated. The absorbents with the highest removal efficiency were date and olives stones and, to a Lesser degree, Raphanus raphanistrum and Cistus ladaniferus. The adsorption tests gave very satisfying results and pointed to the possible application of these supports as ecoLogical remediation techniques to prevent pesticide pollution of aquatic ecosystems.

  7. A pulsed light system for the disinfection of flow through water in the presence of inorganic contaminants.

    Science.gov (United States)

    Garvey, Mary; Rowan, Neil

    2015-06-01

    The use of ultraviolet (UV) light for water disinfection has become increasingly popular due to on-going issues with drinking water and public health. Pulsed UV light has proved to be an effective form of inactivating a range of pathogens including parasite species. However, there are limited data available on the use of pulsed UV light for the disinfection of flowing water in the absence or presence of inorganic contaminants commonly found in water sources. Here, we report on the inactivation of test species including Bacillus endospores following pulsed UV treatment as a flow through system. Significant levels of inactivation were obtained for both retention times tested. The presence of inorganic contaminants iron and/or manganese did affect the rate of disinfection, predominantly resulting in an increase in the levels of inactivation at certain UV doses. The findings of this study suggest that pulsed UV light may provide a method of water disinfection as it successfully inactivated bacterial cells and bacterial endospores in the absence and presence of inorganic contaminants.

  8. Evaluation of energy transfer and utilization efficiency of azo dye removal by different pulsed electrical discharge modes

    Institute of Scientific and Technical Information of China (English)

    SHEN YongJun; LEI LeCheng; ZHANG XingWang

    2008-01-01

    The degradation of an azo dye, acid orange 7 (AO7), caused by different high voltage pulsed electrical discharge modes (spark, streamer and corona discharge) induced by the various initial conductivities was investigated. A new type of pulsed high voltage source with thyratron switch and Blumlein pulse forming net (BPFN) was used. The typical discharge waveforms of voltage, current, power, pulse en-ergy and the pictures of spark, streamer and corona discharge modes were presented. The results in-dicated that pulsed electrical discharges led to complete decolorization and substantial decrease of the chemical oxygen demand (COD) of the dye solution. The main intermediate products were monitored by GC-MS. The discharge modes changed from spark to streamer and to corona discharge, and the streamer length decreased with the liquid conductivity increasing. At a constant input power, the peak voltage, peak current, peak power and energy per pulse of the three discharge modes ranked in the following order: spark > streamer > corona. The effective energy transfer efficiency of AO7 removal was higher for spark discharge (57.2%) than for streamer discharge (40.4%) and corona discharge (27.6%). Moreover, the energy utilization efficiency of AO7 removal for spark discharge was 1.035×109 mol/J, and for streamer and corona discharge they were 0.646×10-8 and 0.589×10-9mol/J. Both the energy transfer efficiency and the energy utilization efficiency of spark discharge were the highest.

  9. The Removal of Confidor Pesticide by Different Species of Trichoderma Fungi from Contaminated Waters

    Directory of Open Access Journals (Sweden)

    Hossein Banejad

    2017-01-01

    Full Text Available Introduction: Pesticides are considered as the most important pollutants in surface water and groundwater. Neonicotinoids are new group of insecticides, derived from nicotine. Their physicochemical properties render them useful for a wide range of application techniques, including foliar, seed treatment, soil drench and stem applications. Confidor, the representative of the first generation of neonicotinoid insecticides, was patented in 1985 by Bayer and was placed on the market in 1991. The Canadian Pest Management Regulatory Agency considers confidor to have high potential for surface water contamination, leaching to groundwater and persistence in soils. Biodegradation is one of the most effective ways to destroy pesticides in the environment. The application of Bioremediation techniques is taken into consideration as an option to reduce or remove pollutants from the environment due to their low cost, high efficiency and environmentally friendly features. Bioremediation by using microorganisms has not any adverse effect after cleanup. The accumulator microorganism species, haven’t pathogenic properties and aren’t the cause of disease on the other organisms. The selection of a biomass for using in bioremediation is very important, it should be abundant in environment and adapted to environmental conditions. The aim of this study was to investigate the ability of various species of Trichoderma fungi to remove Confidor from contaminated water influenced by variables like pH, concentration of the confidor and time. Materials and Methods: In order to conduct this study three different fungal species belonging to the genus Trichoderma were used. The samples were transferred to PDA (Potato Dextrose Agar sterile solid media for in vitro testing usage. The samples were kept in refrigerator at 4◦C temperature, after the fungal biomass reached to maximal growth; the colonies were transferred to new media and used in our experiments as resources

  10. Sonic and ultrasonic removal of chemical contaminants from soil in the laboratory and on a large scale.

    Science.gov (United States)

    Mason, Timothy J; Collings, Anthony; Sumel, Adam

    2004-05-01

    Power ultrasound can be used for the rehabilitation of industrial sites or the reclamation of polluted land by the removal of chemical and biological contamination from soil. In this paper some current laboratory research and the potential for the scale-up of chemical decontamination is reviewed. Two basic mechanisms for acoustically enhanced soil cleaning have been suggested (a). an increase in the abrasion of suspended soil in slurries leading to the removal of contaminated material from the surface of particles and (b). an improvement in leaching out of more deeply entrenched materials.

  11. Potential for contamination during removal of radioactive seeds from surgically excised tissue.

    Science.gov (United States)

    Classic, K L; Brunette, J B; Carlson, S K

    2009-08-01

    The purpose of this study was to determine whether the use of a scalpel or electrocautery to remove radioactive sealed sources ("seeds") from surgically excised tissue could damage the seed and cause it to leak its radioactive contents. Attempts were made to cut or burn Oncura Model 6711 non-radioactive seeds while in pig muscle or on a stainless steel plate. Additionally, one active 125I seed was purposely charred using pressure with an electrocautery knife to see whether the casing could be damaged. Electron microscopy scanning was performed on the dummy seeds to determine if the integrity of the metal casing had been compromised. Two types of leak tests were performed on the active seed to verify the presence or absence of loose contamination. The seed casing was not damaged from either use of a scalpel or electrocautery when the seed was in tissue. The active seed was not found to be leaking after applying pressure with an electrocautery knife while the seed was on a stainless steel plate. We conclude that removal of active Model 6711 seeds from surgically excised tissue can be done safely with a scalpel or electrocautery because constant, firm pressure cannot be applied to the seed. This is likely true for seeds made of similar materials.

  12. Arsenic removal via electrocoagulation from heavy metal contaminated groundwater in La Comarca Lagunera Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Parga, Jose R. [Institute Technology of Saltillo, Department of Metallurgy and Materials Science, V. Carranza 2400, C.P. 25280, Saltillo, Coahuila, Mexico (Mexico)]. E-mail: drjrparga@hotmail.com; Cocke, David L. [Lamar University, Gill Chair of Chemistry and Chemical Engineering, Beaumont, TX 77710 (United States); Valenzuela, Jesus L. [University of Sonora, Hermosillo, Sonora, Mexico (Mexico); Gomes, Jewel A. [Lamar University, Gill Chair of Chemistry and Chemical Engineering, Beaumont, TX 77710 (United States); Kesmez, Mehmet [Lamar University, Gill Chair of Chemistry and Chemical Engineering, Beaumont, TX 77710 (United States); Irwin, George [Lamar University, Department of Chemistry and Physics, Beaumont, TX 77710 (United States); Moreno, Hector [Lamar University, Gill Chair of Chemistry and Chemical Engineering, Beaumont, TX 77710 (United States); Weir, Michael [Lamar University, Gill Chair of Chemistry and Chemical Engineering, Beaumont, TX 77710 (United States)

    2005-09-30

    Arsenic contamination is an enormous worldwide problem. A large number of people dwelling in Comarca Lagunera, situated in the central part of northern Mexico, use well water with arsenic in excess of the water standard regulated by the Secretary of Environment and Natural Resources of Mexico (SEMARNAT), to be suitable for human health. Individuals with lifetime exposure to arsenic develop the classic symptoms of arsenic poisoning. Among several options available for removal of arsenic from well water, electrocoagulation (EC) is a very promising electrochemical treatment technique that does not require the addition of chemicals or regeneration. First, this study will provide an introduction to the fundamental concepts of the EC method. In this study, powder X-ray diffraction, scanning electron microscopy, transmission Moessbauer spectroscopy and Fourier transform infrared spectroscopy were used to characterize the solid products formed at iron electrodes during the EC process. The results suggest that magnetite particles and amorphous iron oxyhydroxides present in the EC products remove arsenic(III) and arsenic(V) with an efficiency of more than 99% from groundwater in a field pilot scale study.

  13. Arsenic removal via electrocoagulation from heavy metal contaminated groundwater in La Comarca Lagunera México.

    Science.gov (United States)

    Parga, Jose R; Cocke, David L; Valenzuela, Jesus L; Gomes, Jewel A; Kesmez, Mehmet; Irwin, George; Moreno, Hector; Weir, Michael

    2005-09-30

    Arsenic contamination is an enormous worldwide problem. A large number of people dwelling in Comarca Lagunera, situated in the central part of northern México, use well water with arsenic in excess of the water standard regulated by the Secretary of Environment and Natural Resources of México (SEMARNAT), to be suitable for human health. Individuals with lifetime exposure to arsenic develop the classic symptoms of arsenic poisoning. Among several options available for removal of arsenic from well water, electrocoagulation (EC) is a very promising electrochemical treatment technique that does not require the addition of chemicals or regeneration. First, this study will provide an introduction to the fundamental concepts of the EC method. In this study, powder X-ray diffraction, scanning electron microscopy, transmission Mössbauer spectroscopy and Fourier transform infrared spectroscopy were used to characterize the solid products formed at iron electrodes during the EC process. The results suggest that magnetite particles and amorphous iron oxyhydroxides present in the EC products remove arsenic(III) and arsenic(V) with an efficiency of more than 99% from groundwater in a field pilot scale study.

  14. Understanding and modeling removal of anionic organic contaminants (AOCs) by anion exchange resins.

    Science.gov (United States)

    Zhang, Huichun; Shields, Anthony J; Jadbabaei, Nastaran; Nelson, Maurice; Pan, Bingjun; Suri, Rominder P S

    2014-07-01

    Ionic organic contaminants (OCs) are a growing concern for water treatment and the environment and are removed inefficiently by many existing technologies. This study examined removal of anionic OCs by anion exchange resins (AXRs) as a promising alternative. Results indicate that two polystyrene AXRs (IRA910 and IRA96) have higher sorption capacities and selectivity than a polyacrylate resin (A860). For the polystyrene resins, selectivity follows: phenolates ≥ aromatic dicarboxylates > aromatic monocarboxylates > benzenesulfonate > aliphatic carboxylates. This trend can be explained based on hydration energy, the number of exchange groups, and aromaticity and hydrophobicity of the nonpolar moiety (NPM) of the anions. For A860, selectivity only varies within a narrow range (0.13-1.64). Despite the importance of the NPM of the anions, neutral solutes were sorbed much less, indicating synergistic combinations of electrostatic and nonelectrostatic interactions in the overall sorption. By conducting multiple linear regression between Abraham's descriptors and nature log of selectivity, induced dipole-related interactions and electrostatic interactions were found to be the most important interaction forces for sorption of the anions, while solute H-bond basicity has a negative effect. A predictive model was then developed for carboxylates and phenolates based on the poly parameter linear free energy relationships established for a diverse range of 16 anions and 5 neutral solutes, and was validated by accurate prediction of sorption of five test solutes within a wide range of equilibrium concentrations and that of benzoate at different pH.

  15. Emerging contaminant degradation and removal in algal wastewater treatment ponds: Identifying the research gaps.

    Science.gov (United States)

    Norvill, Zane N; Shilton, Andy; Guieysse, Benoit

    2016-08-05

    Whereas the fate of emerging contaminants (ECs) during 'conventional' and 'advanced' wastewater treatment (WWT) has been intensively studied, little research has been conducted on the algal WWT ponds commonly used in provincial areas. The long retention times and large surface areas exposed to light potentially allow more opportunities for EC removal to occur, but experimental evidence is lacking to enable definite predictions about EC fate across different algal WWT systems. This study reviews the mechanisms of EC hydrolysis, sorption, biodegradation, and photodegradation, applying available knowledge to the case of algal WWT. From this basis the review identifies three main areas that need more research due to the unique environmental and ecological conditions occurring in algal WWT ponds: i) the effect of diurnally fluctuating pH and dissolved oxygen upon removal mechanisms; ii) the influence of algae and algal biomass on biodegradation and sorption under relevant conditions; and iii) the significance of EC photodegradation in the presence of dissolved and suspended materials. Because of the high concentration of dissolved organics typically found in algal WWT ponds, most EC photodegradation likely occurs via indirect mechanisms rather than direct photolysis in these systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. BIOLOGICALLY-MEDIATED REMOVAL AND RECOVERY OF PLUTONIUM FROM CONTAMINATED SOIL

    Energy Technology Data Exchange (ETDEWEB)

    Jerger, Douglas E., Ph.D.,; Alperin, Edward S., QEP,; Holmes, Robert G., Ph.D.

    2003-02-27

    An innovative biological treatment technology successfully reduced plutonium concentration in soil from the Nevada Test Site (NTS) by over 80%. The final volume of plutonium-contaminated material that required disposal was reduced by over 90%. These results, achieved by an independent testing laboratory, confirm the results reported previously using NTS soil. In the previous test a 2530-gram sample of soil (350 to 400 pCi/g Pu) resulted in production of 131 grams of sludge (6,320 pCi/ g Pu) and a treated soil containing 72 pCi/g of Pu. The technology is based on the biological acidification of the soil and subsequent removal of the plutonium and other dissolved metals by a low volume, low energy water leaching process. The leachate is treated in a sulfate-reducing bioreactor to precipitate the metals as metal sulfides. Water may be recycled as process water or disposed since the treatment process removes over 99% of the dissolved metals including plutonium from the water. The plutonium is contained as a stable sludge that can be containerized for final disposal. Full-scale process costs have been developed which employ widely used treatment technologies such as aerated soil piles (biopiles) and bioreactors. The process costs were less than $10 per cubic foot, which were 40 to 50% lower than the baseline costs for the treatment of the NTS soil. The equipment and materials for water and sludge treatment and soil handling are commercially available.

  17. Removal Of Contaminants From Aqueous Solutions Using Hop (Humulus Lupulus L. Agricultural By-Products

    Directory of Open Access Journals (Sweden)

    Partelová Denisa

    2015-12-01

    Full Text Available Agricultural wastes can be used as an alternative to the existing sorbents for the removal of metals or synthetic dyes from contaminated liquids. In this work, the fine powdered biomass of the hop (Humulus lupulus L. variety Osvald's clone 72 and variety Bohemie as a sorbent for the removal of Cd from aqueous solutions of CdCl2 spiked with radionuclide 109Cd and synthetic dyes thioflavine T (ThT or methylene blue (MB from single dye solutions under conditions of batch systems was used. The maximum sorption capacity Q = 264 µmol Cd/g (d.w. was found in the case of the leaf biomass of hop (H. lupulus L. variety Osvald's clone 72 at the initial concentration of CdCl2 10,000 µmol/dm3, whereby the sorption capacity decreased in the order Qleaves : Qstems : Qroots = 1.0 : 0.8 : 0.7. The sorbed amount of Cd was removed from the hop biomass with the following increasing desorption efficiency of the extraction reagents: deionised H2O << 0.1 mol/dm3 HCl ≤ 0.1 mol/dm3 EDTA-Na2. Similarly as in the case of Cd sorption, the kinetics of ThT and MB sorption by the leaf biomass of the hop (H. lupulus L. variety Bohemie were also showed as two-phase processes. The maximum sorption of ThT approx. Q = 19 mg/g (d.w. and MB approx. Q = 70 mg/g (d.w. were found within the range of the initial values of pH 4 – 7. The sorption of both dyes by the leaf biomass from single dye solutions decreased with increasing biomass concentration and on the other hand increased with increasing the initial concentrations of ThT or MB. The process of ThT and MB sorption was better described by the Langmuir model than the Freundlich model of sorption isotherm. From the obtained values of Qmax, it was found that in the case of MB the dried leaf biomass showed more than 2-times higher sorption capacity (Qmax = 184 mg/g; d.w. in comparison with the value predicted for ThT. Obtained results suggest that dried plant biomass of hop (H. lupulus L. as agricultural by-products can be used

  18. Removal of trichloroethylene (TCE) contaminated soil using a two-stage anaerobic-aerobic composting technique.

    Science.gov (United States)

    Ponza, Supat; Parkpian, Preeda; Polprasert, Chongrak; Shrestha, Rajendra P; Jugsujinda, Aroon

    2010-01-01

    The effect of organic carbon addition on remediation of trichloroethylene (TCE) contaminated clay soil was investigated using a two stage anaerobic-aerobic composting system. TCE removal rate and processes involved were determined. Uncontaminated clay soil was treated with composting materials (dried cow manure, rice husk and cane molasses) to represent carbon based treatments (5%, 10% and 20% OC). All treatments were spiked with TCE at 1,000 mg TCE/kg DW and incubated under anaerobic and mesophillic condition (35 degrees C) for 8 weeks followed by continuous aerobic condition for another 6 weeks. TCE dissipation, its metabolites and biogas composition were measured throughout the experimental period. Results show that TCE degradation depended upon the amount of organic carbon (OC) contained within the composting treatments/matrices. The highest TCE removal percentage (97%) and rate (75.06 micro Mole/kg DW/day) were obtained from a treatment of 10% OC composting matrices as compared to 87% and 27.75 micro Mole/kg DW/day for 20% OC, and 83% and 38.08 micro Mole/kg DW/day for soil control treatment. TCE removal rate was first order reaction kinetics. Highest degradation rate constant (k(1) = 0.035 day(- 1)) was also obtained from the 10% OC treatment, followed by 20% OC (k(1) = 0.026 day(- 1)) and 5% OC or soil control treatment (k(1) = 0.023 day(- 1)). The half-life was 20, 27 and 30 days, respectively. The overall results suggest that sequential two stages anaerobic-aerobic composting technique has potential for remediation of TCE in heavy texture soil, providing that easily biodegradable source of organic carbon is present.

  19. Investigations on removal of SO2 from flue gas by aerosol formation in pulsed corona discharge process

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The removal of SO2 from flue gas by pulsed coronadischarge in presence of ammonia was experimentally investigated.The results show that the SO2 removal mainly depend on thermalreaction of SO2 with NH3 and enhancement of 0%-25% by pulsed coronadischarge in the range of the specific energy 0-5 Wh/Nm3. Theaerosol mass concentration, mainly composed of ammonium sulfate,increases with specific energy dissipated into the reactor. With aninitial concentration of 2000-2100 ppmv SO2 and energy consumptionof 3 Wh/Nm3, when a stoichiometric amount of ammonia is injected,the removal efficiency of SO2 and percentage of ammonium sulfatesin reaction products are all ≥80%. The collection efficiency of thereactor for aerosol is about 74% at a flue gas temperature of 60 to65℃ and a water vapor content of 9% to 11% volume.

  20. Pulse

    Science.gov (United States)

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the person's heart is pumping. Pulse ... rate gives information about your fitness level and health.

  1. Non-inferiority of pulsed xenon UV light versus bleach for reducing environmental Clostridium difficile contamination on high-touch surfaces in Clostridium difficile infection isolation rooms.

    Science.gov (United States)

    Ghantoji, Shashank S; Stibich, Mark; Stachowiak, Julie; Cantu, Sherry; Adachi, Javier A; Raad, Issam I; Chemaly, Roy F

    2015-02-01

    The standard for Clostridium difficile surface decontamination is bleach solution at a concentration of 10 % of sodium hypochlorite. Pulsed xenon UV light (PX-UV) is a means of quickly producing germicidal UV that has been shown to be effective in reducing environmental contamination by C. difficile spores. The purpose of this study was to investigate whether PX-UV was equivalent to bleach for decontamination of surfaces in C. difficile infection isolation rooms. High-touch surfaces in rooms previously occupied by C. difficile infected patients were sampled after discharge but before and after cleaning using either bleach or non-bleach cleaning followed by 15 min of PX-UV treatment. A total of 298 samples were collected by using a moistened wipe specifically designed for the removal of spores. Prior to disinfection, the mean contamination level was 2.39 c.f.u. for bleach rooms and 22.97 for UV rooms. After disinfection, the mean level of contamination for bleach was 0.71 c.f.u. (P = 0.1380), and 1.19 c.f.u. (P = 0.0017) for PX-UV disinfected rooms. The difference in final contamination levels between the two cleaning protocols was not significantly different (P = 0.9838). PX-UV disinfection appears to be at least equivalent to bleach in the ability to decrease environmental contamination with C. difficile spores. Larger studies are needed to validate this conclusion. © 2015 The Authors.

  2. Influences of Excess Oscillation of Voltage Pulse and Discharge Mode on NO Removal Using Barrier-Type Plasma Reactor

    Science.gov (United States)

    Kadowaki, Kazunori; Suzuki, Yoshiaki; Ihori, Haruo; Kitani, Isamu

    This paper presents experimental results of NO removal from a simulated exhausted-gas using a barrier type reactor with screw electrodes subjected to polarity-reversed voltage pulses. The polarity-reversed pulse was produced by direct grounding of a charged coaxial cable because a traveling wave voltage was negatively reflected at the grounding end with a change in its polarity and then it propagated to the plasma reactor at the opposite end. Influence of cable length on NO removal was studied for two kinds of cable connection, single-connected cable and parallel-connected cables. NO removal ratio for a 50m-long cable was lower than that for much shorter cables in both single and parallel connections when the applied voltage became high. Energy efficiency for NO removal also increased with decreasing the cable length. This was because excess discharges during the voltage oscillation caused by the large stored energy in the long cable resulted in reproduction of NO molecules. Energy efficiency was further improved by changing the discharge mode from dielectric barrier discharge (DBD) to surface discharge (SD). Energy efficiency was up to 110g/kWh with 55% NO removal ratio and 34g/kWh with 100% NO removal ratio by using a single 10m-long cable in SD mode.

  3. Removal of Lead from Wastewater Contaminated with Chemical Synthetic Dye by Aspergillus terreus

    Directory of Open Access Journals (Sweden)

    Lamyai Neeratanaphan

    2015-07-01

    Full Text Available Novel isolated microorganisms have been demonstrated to efficiently remove lead from wastewater contaminated with chemical synthetic dye. In this study, the physical and chemical parameters of wastewater samples (including Pb concentrations were analyzed before and after treatment with microorganisms. The highest Pb concentration detected in wastewater was 0.788 mg/l. Investigations of the Pb tolerance and removal capacities of microorganism strains isolated from the wastewater sediment resulted in the selection of three fungal isolates (F102, F203 and F302. Interestingly, isolate F203 had a Pb tolerance of up to 100 mg/l. Using DNA barcoding and morphological characteristics, fungal isolate F203 was identified as Aspergillus terreus. Wastewater characteristics before treatment included a grayish black color with pH, TDS, BOD, COD and Pb concentrations higher than the Thailand standard values. Wastewater qualities after treatment with A. terreus showed definite improvement; however, the values of certain parameters were still higher than the allowed values based on the Thailand standard. The only improvement that fell within the allowed standard was the Pb concentration. Next, A. terreus was used for Pb adsorption in wastewater with an initial Pb concentration of 0.788 mg/l at time points corresponding to 0, 24, 48, 72, 96, 120, 144 and 168 h of incubation. The results showed that A. terreus could adsorb and remove higher amounts of Pb from wastewater than the other fungal isolates. Time course adsorption analysis showed the remaining Pb concentrations as 0.788, 0.213, 0.162, 0.117, 0.100, 0.066, 0.042 and 0.032 mg/l, respectively; the percentage of Pb removal could be estimated as 0, 72.97, 79.44, 85.15, 87.31, 91.62, 94.67 and 95.94%, respectively. In conclusion, A. terreus possessed the ability to adsorb up to 96% of Pb from chemical synthetic dye within 168 h. Thus, A. terreus might be suitable for adaptation and use in Pb treatment.

  4. Removal of Contaminant Nanoparticles from Wastewater Produced Via Hydrothermal Carbonization by SPIONs

    Science.gov (United States)

    Parsapour, Melika

    purified graphene oxide (GO), which was afterwards coated with PEG (20000Da), resulting in SPIONs/GO PEG. As GO has various functional groups that have a high valence for absorption of contaminants due to their oxygen content, we assume that SPIONs/GO PEG improves the efficiency of the decontamination process compared to SPIONs PEG alone. Initially, we have characterized the synthetized SPIONs. Fourier Transform Infrared spectroscopy (FT-IR) was used to identify the present functional groups in the SPIONs samples. Atomic Force Microscopy (AFM) and Transmission Electronic Microscopy (TEM) were used to determine the topography and diameter size via high resolution images with fine details of the nanocomposites. Finally Dynamic Light Scattering (DLS) was used to evaluate the size distribution of the SPIONs in distilled water. Also, all wastewater samples were characterized before and after treatment. FT-IR was used to determine the functional groups in initial samples. Ultraviolet-visible spectroscopy (UV-vis) was used to observe the UV absorption of the chemicals. DLS was used for size distribution and density measurement, and morphology investigation was done by AFM technique. The SPIONs which involved the GO due to the presence of oxidizes groups showed a better ordered crystalline structure and a narrower diameter distribution. The glycerin samples treated by SPIONs PEG and SPIONs/GO PEG demonstrated 43% and 38% reduction in contaminant respectively. As for the sugar samples, the reductions were of 33% and 60% respectively. Thus, the obtained results confirm the capability of the nanocomposites to remove the nano contaminant from wastewater samples reasonably. However, the decontamination power of the nanocomposites differs accordingly to the chemical structure of the initial biomass.

  5. Method and device for the removal of contaminants from surfaces. Apparat for aa fjerne forurensninger fra overflater

    Energy Technology Data Exchange (ETDEWEB)

    Kelsall, T.W.

    1988-11-28

    The invention deals with a method and device for decontamination of a surface, where particles of ice or another frozen liquid are aimed at the surface. The frozen particles used will melt, and they can easily be removed and, if necessary, separated from the contamination from the surface.

  6. Removal of Contaminants from Equipment and Debris and Waste Minimization Using the TECHXTRACT(TM) Technology

    Energy Technology Data Exchange (ETDEWEB)

    Jorg Schwitzgebel; Klaus Schwitzgebel; Michael W. Bonem; Ronald E. Borah

    1998-12-09

    From September, 1996 through July, 1997, EET, Inc. conducted a series of experiments under a U.S. Department of Energy (DOE) Program Research and Development Agreement (PRDA). This project, entitled "Removal of Contaminants from Equipment and Debris and Waste Minimization Using the TECHXTRACT â Technology" was conducted under DOE Contract DE-AC21- 96MC33138, administered by the Federal Energy Technology Center. The contract is divided into two phases - a base phase during which bench scale testing was conducted; and an optional phase for a field demonstration of a full-scale system. This report documents the results from the base phase of the contract. The base phase included the following major elements: - Evaluation of the effectiveness of various decontamination options, using both surrogate and radioactively contaminated samples. - Evaluation of various methods for the treatment of the secondary waste streams from the preferred decontamination system(s). - Evaluation of decontamination effectiveness for concrete rubble. - Preliminary engineering design and cost estimation for a full-scale system. - Preliminary economic analysis of the proposed system versus other currently available options for disposition of the materials. Results from the base phase, which are described in the following report, are very positive. Testing has shown that free release requirements and extremely high decontamination factors can be achieved for a variety of materials and radionuclides. Results for concrete rubble decontamination were less conclusive. The bench scale testing has led to the design of two different systems, both based on the TECHXTRACT â chemistry, for potential full-scale demonstration. Based on the preliminary economic analysis, this system compares favorably with currently available commercial options, including disposal.

  7. Effect of processing for saponin removal on fungal contamination of quinoa seeds (Chenopodium quinoa Willd.).

    Science.gov (United States)

    Pappier, Ursula; Fernández Pinto, Virginia; Larumbe, Gabriela; Vaamonde, Graciela

    2008-07-15

    Incidence of fungal contamination of quinoa seeds from three locations (Salar de Uyuni, Bolivia; Salta and Tucumán provinces, Argentina) was analyzed in samples with and without treatment to remove saponins (wet method). In processed samples, the percentage of infection was reduced. Distribution of the different fungal genera was not homogeneous in the three locations (p<0.05), although Penicillium and Aspergillus were the most prevalent contaminants, regardless the geographic origin of the samples. Other genera, such as Eurotium, Fusarium, Phoma, Ulocladium, Mucor and Rhizopus were less frequently isolated. Absidia, Alternaria, Cladosporium, Dreschlera, Epicoccum and Monascus were sporadically encountered. Significant differences (p<0.05) in the distribution of fungal genera in samples with and without saponins from each location were observed. In all cases, processing caused a decrease of Aspergillus incidence, while increased the proportion of Penicillium, Eurotium, Mucor and Rhizopus indicating that these genera were part of the internal mycota. A. flavus and A. niger were the dominating species of genus Aspergillus. A similar pattern of prevalent Penicillium species was observed in samples with and without saponins, since P. aurantiogriseum, P.chrysogenum, P. citrinum and P. crustosum were always present in high number, although their relative density was variable according to the geographic origin of samples. Mycotoxin-producing ability of most representative species was also determined. Toxigenic strains of A. flavus (aflatoxins and cyclopiazonic acid), A. parasiticus (aflatoxins), P. citrinum (citrinin) and P. griseofulvum (cyclopiazonic acid) were found. None of the A. niger isolates was ochratoxin A producer. The above mentioned mycotoxins were not detected in the samples analyzed.

  8. Removal of volatile to semi-volatile organic contaminants from water using hollow fiber membrane contactors and catalytic destruction of the contaminants in the gas phase

    OpenAIRE

    Tarafder, Shamsul Abedin

    2007-01-01

    Abstract Chlorinated organic compounds and ether compounds are frequently found in groundwater and efficient treatment options are needed. In this study, the efficient transferal of the compounds from the water phase to the gas phase was studied followed by the catalytic treatment of the gas phase. For the removal of the organic contaminants from water, a microporous polypropylene hollow fiber membrane (HFM) module was operated under low strip gas flow to water flow ratios (_< 5:1). Rem...

  9. Characterization of chemical contaminants and their spectral properties from an atmospheric pressure ns-pulsed microdischarge in neon

    Science.gov (United States)

    Sillerud, Colin H.; Schwindt, Peter D. D.; Moorman, Mathew; Yee, B. T.; Anderson, John; Pfeifer, Nathaniel B.; Hedberg, E. L.; Manginell, Ronald P.

    2017-03-01

    Portable applications of microdischarges, such as the remediation of gaseous wastes or the destruction of volatile organic compounds, will mandate operation in the presence of contaminant species. This paper examines the temporal evolution of microdischarge optical and ultraviolet emissions during pulsed operation by experimental methods. By varying the pulse length of a microdischarge initiated in a 4-hole silicon microcavity array operating in a 655 Torr ambient primarily composed of Ne, we were able to measure the emission growth rates for different contaminant species native to the discharge environment as a function of pulse length. It was found that emission from hydrogen and oxygen impurities demonstrated similar rates of change, while emissions from molecular and atomic nitrogen, measured at 337.1 and 120 nm, respectively, exhibited the lowest rate of change. We conclude that it is likely that O2 undergoes the same resonant energy transfer process between rare gas excimers that has been shown for H2. Further, efficient resonant processes were found to be favored during ignition and extinction phases of the pulse, while emission at the 337.1 nm line from N2 was favored during the intermediate stage of the plasma. In addition to the experimental results, a zero-dimensional analysis is also presented to further understand the nature of the microdischarge.

  10. Removal of oil droplets from contaminated water using magnetic carbon nanotubes.

    Science.gov (United States)

    Wang, Haitao; Lin, Kun-Yi; Jing, Benxin; Krylova, Galyna; Sigmon, Ginger E; McGinn, Paul; Zhu, Yingxi; Na, Chongzheng

    2013-08-01

    Water contaminated by oil and gas production poses challenges to the management of America's water resources. Here we report the design, fabrication, and laboratory evaluation of multi-walled carbon nanotubes decorated with superparamagnetic iron-oxide nanoparticles (SPIONs) for oil-water separation. As revealed by confocal laser-scanning fluorescence microscopy, the magnetic carbon nanotubes (MCNTs) remove oil droplets through a two-step mechanism, in which MCNTs are first dispersed at the oil-water interface and then drag the droplets with them out of water by a magnet. Measurements of removal efficiency with different initial oil concentration, MCNT dose, and mixing time show that kinetics and equilibrium of the separation process can be described by the Langmuir model. Separation capacity qt is a function of MCNT dose m, mixing time t, and residual oil concentration Ce at equilibrium: [Formula in text] where qmax, kw, and K are maximum separation capacity, wrapping rate constant, and equilibrium constant, respectively. Least-square regressions using experimental data estimate qmax = 6.6(± 0.6) g-diesel g-MCNT(-1), kw = 3.36(± 0.03) L g-diesel(-1) min(-1), and K = 2.4(± 0.2) L g-diesel(-1). For used MCNTs, we further show that over 80% of the separation capacity can be restored by a 10 min wash with 1 mL ethanol for every 6 mg MCNTs. The separation by reusable MCNTs provides a promising alternative strategy for water treatment design complementary to existing ones such as coagulation, adsorption, filtration, and membrane processes.

  11. Isolation of Listeria monocytogenes in a salami producing plant in Piedmont: use of pulsed field gel electrophoresis to trace contaminations

    Directory of Open Access Journals (Sweden)

    Annalisa Costa

    2013-06-01

    Full Text Available The ability of Listeria monocytogenes to survive in different environments and establish persistent contaminations is an important issue for food producers. This study aimed to assess the environmental contamination level in an Italian salami producing plant and to identify possible sources of contamination using pulsed field gel electrophoresis (PFGE on L. monocytogenes isolates obtained from environmental (n=54 and meat samples (n=9 collected over 9 months. Detection of L. monocytogenes was performed using the UNI EN ISO 11290-1 procedure and every isolate was characterised with PFGE, using AscI and ApaI restriction enzymes. The environmental detection frequencies were constant both in the first (22% and the second (27% visit, thus suggesting the presence of strains adapted to the processing plant. Equipments can represent a reservoir of L. monocytogenes from which it can spread into the whole producing plant. The reservoir was documented by PFGE results which showed several persistent strains. Moreover, PFGE proved the cross-contamination between surfaces and semiprocessed products like pastes, which furthermore have been contaminated by L. monocytogenes in 100% of samples in the first two visits and in 33% in the last visit. This study gave evidence that detection methods and PFGE characterisation can be effective tools to detect possible sources and routes of contamination.

  12. Correlation Among Soil Enzyme Activities, Root Enzyme Activities, and Contaminant Removal in Two-Stage In Situ Constructed Wetlands Purifying Domestic Wastewater.

    Science.gov (United States)

    Ni, Lixiao; Xu, Jiajun; Chu, Xianglin; Li, Shiyin; Wang, Peifang; Li, Yiping; Li, Yong; Zhu, Liang; Wang, Chao

    2016-07-01

    Two-stage in situ wetlands (two vertical flow constructed wetlands in parallel and a horizontal flow constructed wetland) were constructed for studying domestic wastewater purification and the correlations between contaminant removal and plant and soil enzyme activities. Results indicated the removal efficiency of NH4 (+) and NO3 (-) were significantly correlated with both urease and protease activity, and the removal of total phosphorus was significantly correlated with phosphatase activity. Chemical oxygen demand removal was not correlated with enzyme activity in constructed wetlands. Plant root enzyme (urease, phosphatase, protease and cellulose) activity correlation was apparent with all contaminant removal in the two vertical flow constructed wetlands. However, the correlation between the plant root enzyme activity and contaminant removal was poor in horizontal flow constructed wetlands. Results indicated that plant roots clearly played a role in the removal of contaminants.

  13. Non-inferiority of pulsed xenon UV light versus bleach for reducing environmental Clostridium difficile contamination on high-touch surfaces in Clostridium difficile infection isolation rooms

    National Research Council Canada - National Science Library

    Ghantoji, Shashank S; Stibich, Mark; Stachowiak, Julie; Cantu, Sherry; Adachi, Javier A; Raad, Issam I; Chemaly, Roy F

    2015-01-01

    ... % of sodium hypochlorite. Pulsed xenon UV light (PX-UV) is a means of quickly producing germicidal UV that has been shown to be effective in reducing environmental contamination by C. difficile spores...

  14. Phytoremediation: a technology using green plants to remove contaminants from polluted areas.

    Science.gov (United States)

    Garbisu, Carlos; Hernández-Allica, Javier; Barrutia, Oihana; Alkorta, Itziar; Becerril, José M

    2002-01-01

    Phytoremediation is an emerging cost-effective, non-intrusive, esthetically pleasing, and low cost technology using the remarkable ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. Phytoremediation technology is applicable to a broad range of contaminants, including metals and radionuclides, as well as organic compounds like chlorinated solvents, polychlorobiphenyls, polycyclic aromatic hydrocarbons, pesticides/insecticides, explosives, and surfactants. The use of plants to transport and concentrate metals from the soil into the harvestable parts of roots and above-ground shoots, usually called 'phytoextraction', has appeared on the scene as a valid alternative to traditional physicochemical remediation methods that do not provide acceptable solutions for the removal of metals from soils. Positive results are becoming available regarding the ability of plants to degrade certain organic compounds. Nonetheless, despite the firm establishment of phytoremediation technology in the literature and in extensive research study and in small-scale demonstrations, full-scale applications are currently limited to a small number of projects. At present, the phytoremediation of metal pollutants from the environment could be approaching commercialization.

  15. Graphene nanosheets and graphite oxide as promising adsorbents for removal of organic contaminants from aqueous solution.

    Science.gov (United States)

    Ji, Liangliang; Chen, Wei; Xu, Zhaoyi; Zheng, Shourong; Zhu, Dongqiang

    2013-01-01

    Graphenes are an emerging class of carbon nanomaterials whose adsorption properties toward organic compounds have not been well understood. In the present study, graphene nanosheets were prepared by reoxidation and abrupt heating of graphite oxide, which was prepared by sequential chemical oxidation of commercial nonporous graphite powder. Adsorption properties of three aromatic compounds (naphthalene, 2-naphthol, and 1-naphthylamine) and one pharmaceutical compound (tylosin) on graphene nanosheets and graphite oxide were examined to explore the potential of these two adsorbents for the removal of organic contaminants from aqueous solutions. Compared with the literature data of adsorption on carbon nanotubes, adsorption of bulky, flexible tylosin on graphene nanosheets exhibited markedly faster adsorption kinetics, which can be attributed to their opened-up layer structure. Graphene nanosheets and graphite oxide showed similar sequences of adsorption affinity: 1-naphthylamine > 2-naphthol > tylosin > naphthalene (with much larger differences observed on graphite oxide). It was proposed that the strong adsorption of the three aromatic compounds was mainly due to π-π electron donor-acceptor interactions with the graphitic surfaces of adsorbents. Additionally, Lewis acid-base interaction was likely an important factor contributing to the strong adsorption of 1-naphthylamine and tylosin, especially for the O-functionality-abundant graphite oxide. After being normalized on the basis of adsorbent surface area, adsorption affinities of all four tested adsorbates on graphene nanosheets were very close to those on nonporous graphite powder, reflecting complete accessibility of the adsorbent surface area in adsorption.

  16. Contaminant removal in septage treatment with vertical flow constructed wetlands operated under batch flow conditions.

    Science.gov (United States)

    Jong, Valerie Siaw Wee; Tang, Fu Ee

    2016-01-01

    Individual septic tanks are the most common means of on-site sanitation in Malaysia, but they result in a significant volume of septage. A two-staged vertical flow constructed wetlands (VFCWs) system for the treatment of septage was constructed and studied in Sarawak, Malaysia. Raw septage was treated in the first stage wetlands, and the resulting percolate was fed onto the second stage wetlands for further treatment. Here, the effects of a batch loading regime on the contaminant removal efficiency at the second stage wetlands, which included palm kernel shell within their filter substrate, are presented. The batch loading regime with pond:rest (P:R) period of 1:1, 2:2 and 3:3 (day:day) was studied. The improvement of the effluent redox condition was evident with P:R = 3:3, resulting in excellent organic matters (chemical oxygen demand and biochemical oxygen demand) and nitrogen reduction. The bed operated with P:R = 1:1 experienced constant clogging, with a water layer observed on the bed surface. For the P:R = 3:3 regime, the dissolved oxygen profile was not found to decay drastically after 24 hours of ponding, suggesting that the biodegradation mainly occurred during the first day. The study results indicate that a suitable application regime with an adequate rest period is important in VFCWs to ensure efficient operation.

  17. Study of cyanide removal from contaminated water using zinc peroxide nanomaterial.

    Science.gov (United States)

    Uppal, Himani; Tripathy, S Swarupa; Chawla, Sneha; Sharma, Bharti; Dalai, M K; Singh, S P; Singh, Sukhvir; Singh, Nahar

    2017-05-01

    The present study highlights the potential application of zinc peroxide (ZnO2) nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis has been granted in United States of America (US Patent number 8,715,612; May 2014), South Africa, Bangladesh, and India. The ZnO2 nanomaterial was capped with polyvinylpyrrolidone (PVP) to control the particle size. The PVP capped ZnO2 nanomaterial (PVP-ZnO2) before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractometer, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. The remaining concentration of cyanide after adsorption by PVP-ZnO2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15min. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics. Copyright © 2016. Published by Elsevier B.V.

  18. Potential of phytoremediation for the removal of petroleum hydrocarbons in contaminated salt marsh sediments.

    Science.gov (United States)

    Ribeiro, Hugo; Mucha, Ana P; Almeida, C Marisa R; Bordalo, Adriano A

    2014-05-01

    Degradation of petroleum hydrocarbons in colonized and un-colonized sediments by salt marsh plants Juncus maritimus and Phragmites australis collected in a temperate estuary was investigated during a 5-month greenhouse experiment. The efficiency of two bioremediation treatments namely biostimulation (BS) by the addition of nutrients, and bioaugmentation (BA) by addition of indigenous microorganisms was tested in comparison with hydrocarbon natural attenuation in un-colonized and with rhizoremediation in colonized sediments. Hydrocarbon degrading microorganisms and root biomass were assessed as well as hydrocarbon degradation levels. During the study, hydrocarbon degradation in un-colonized sediments was negligible regardless of treatments. Rhizoremediation proved to be an effective strategy for hydrocarbon removal, yielding high rates in most experiments. However, BS treatments showed a negative effect on the J. maritimus potential for hydrocarbon degradation by decreasing the root system development that lead to lower degradation rates. Although both plants and their associated microorganisms presented a potential for rhizoremediation of petroleum hydrocarbons in contaminated salt marsh sediments, results highlighted that nutrient requirements may be distinct among plant species, which should be accounted for when designing cleanup strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Microbial Diversity of Chromium-Contaminated Soils and Characterization of Six Chromium-Removing Bacteria

    Science.gov (United States)

    He, Zhiguo; Hu, Yuting; Yin, Zhen; Hu, Yuehua; Zhong, Hui

    2016-06-01

    Three soil samples obtained from different sites adjacent to a chromium slag heap in a steel alloy factory were taken to examine the effect of chromium contamination on soil bacterial diversity as determined by construction of 16S rDNA clone libraries and sequencing of selected clones based on restriction fragment length polymorphism (RFLP) analysis. Results revealed that Betaproteobacteria, Gammaproteobacteria, Firmicutes, and Alphaproteobacteria occurred in all three soil samples, although the three samples differed in their total diversity. Sample 1 had the highest microbial diversity covering 12 different classes, while Sample 3 had the lowest microbial diversity. Strains of six different species were successfully isolated, one of which was identified as Zobellella denitrificans. To our knowledge, this is the first report of a strain belonging to the genus Zobellella able to resist and reduce chromium. Among all isolates studied, Bacillus odysseyi YH2 exhibited the highest Cr(VI)-reducing capability, with a total removal of 23.5 % of an initial Cr(VI) concentration of 350 mg L-1.

  20. Removal of As, Cd, Cu, Ni, Pb, and Zn from a highly contaminated industrial soil using surfactant enhanced soil washing

    Science.gov (United States)

    Torres, Luis G.; Lopez, Rosario B.; Beltran, Margarita

    Surfactant enhanced soil washing (SESW) was applied to an industrial contaminated soil. A preliminary characterization of the soil regarding the alkaline-earth metals, Na, K, Ca and Mg took values of 2866, 2036, 2783 and 4149 mg/kg. The heavy metals As, Cd, Cu, Pb, Ni and Zn, had values of 4019, 14, 35582, 70, 2603, and 261 mg/kg, respectively. When using different surfactants, high removal of Cu, Ni and Zn were found, and medium removals for Pb, As and Cd. In the case of these three metals, tap water removed more than the surfactant solutions, except for the case of As. There were surfactants with average removals (this is, the removal for all the metals studied) of 67.1% (Tween 80), 64.9% (Surfacpol 14104) and 61.2% (Emulgin W600). There were exceptional removals using Texapon N-40 (83.2%, 82.8% and 86.6% for Cu, Ni and Zn), Tween 80 (85.9, 85.4 and 81.5 for Cd, Zn and Cu), Polafix CAPB (79%, 83.2% and 49.7% for Ni, Zn and As). The worst results were obtained with POLAFIX LO with a global removal of 45%, well below of the average removal with tap water (50.2%).All removal efficiencies are reported for a one step washing using 0.5% surfactant solutions, except for the case of mezquite gum, where a 0.1% solution was employed.

  1. Selective removal of carious human dentin using a nanosecond pulsed laser operating at a wavelength of 5.85 μ m

    Science.gov (United States)

    Ishii, Katsunori; Kita, Tetsuya; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2015-05-01

    Less invasive methods for treating dental caries are strongly desired. However, conventional dental lasers do not always selectively remove caries or ensure good bonding to the composite resin. According to our previous study, demineralized dentin might be removed by a nanosecond pulsed laser operating at wavelengths of around 5.8 μm. The present study investigated the irradiation effect of the light on carious human dentin classified into "remove," "not remove," and "unclear" categories. Under 5.85-μm laser pulses, at average power densities of 30 W/cm2 and irradiation time of 2 s, the ablation depth of "remove" and "not remove," and also the ablation depth of "unclear" and "not remove," were significantly different (p<0.01). The ablation depth was correlated with both Vickers hardness and Ca content. Thus, a nanosecond pulsed laser operating at 5.85 μm proved an effective less-invasive caries treatment.

  2. Numerical modeling and experimental analysis of volatile contaminant removal from vertical flow filters

    NARCIS (Netherlands)

    De Biase, C.

    2012-01-01

    Vertical flow filters (unplanted) and vertical flow constructed wetlands (planted), simple and inexpensive technologies to treat effectively volatile organic compounds (VOCs) contaminated water, consist of containers filled with granular material which is intermittently fed with contaminated water.

  3. An integrated method incorporating sulfur-oxidizing bacteria and electrokinetics to enhance removal of copper from contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Maini, G.; Sharman, A.K.; Sunderland, G.; Knowles, C.J.; Jackman, S.A.

    2000-03-15

    The combination of bioleaching and electrokinetics for the remediation of metal contaminated land has been investigated. In bioleaching, bacteria convert reduced sulfur compounds to sulfuric acid, acidifying soil and mobilizing metal ions. In electrokinetics, DC current acidifies soil, and mobilized metals are transported to the cathode by electromigration. When bioleaching was applied to silt soil artificially contaminated with seven metals and amended with sulfur, bacterial activity was partially inhibited and limited acidification occurred. Electrokinetic treatment of silt soil contaminated solely with 1000 mg/kg copper nitrate showed 89% removal of copper from the soil within 15 days. To combine bioleaching and electrokinetics sequentially, preliminary partial acidification was performed by amending copper-contaminated soil with sulfur (to 5% w/w) and incubating at constant moisture (30% w/w) and temperature (20 C) for 90 days. Indigenous sulfur oxidizing bacteria partially acidified the soil from pH 8.1 to 5.4. This soil was then treated by electrokinetics yielding 86% copper removal in 16 days. In the combined process, electrokinetics stimulated sulfur oxidation, by removing inhibitory factors, yielding a 5.1-fold increase in soil sulfate concentration. Preacidification by sulfur-oxidizing bacteria increased the cost-effectiveness of the electrokinetic treatment by reducing the power requirement by 66%.

  4. Evaluation of the seasonal performance of a water reclamation pond-constructed wetland system for removing emerging contaminants.

    Science.gov (United States)

    Matamoros, Víctor; Salvadó, Victòria

    2012-01-01

    The capacity of a full-scale reclamation pond-constructed wetland (CW) system to eliminate 27 emerging contaminants (i.e. pharmaceuticals, sunscreen compounds, fragrances, antiseptics, fire retardants, pesticides, and plasticizers) and the seasonal occurrence of these contaminants is studied. The compounds with the highest concentrations in the secondary effluent are diclofenac, caffeine, ketoprofen, and carbamazepine. The results show that the constructed wetland (61%) removes emerging contaminants significantly more efficiently than the pond (51%), presumably due to the presence of plants (Phragmites and Thypa) as well as the higher hydraulic residence time (HRT) in the CW. A greater seasonal trend to the efficient removal of these compounds is observed in the pond than in the CW. The overall mass removal efficiency of each individual compound ranged from 27% to 93% (71% on average), which is comparable to reported data in advanced treatments (photo-fenton and membrane filtration). The seasonal average content of emerging contaminants in the river water (2488 ng L(-1)) next to the water reclamation plant is found to be higher than the content in the final reclaimed water (1490 ng L(-1)), suggesting that the chemical quality of the reclaimed water is better than available surface waters.

  5. Assessment of the contaminants level in recycled aggregates and alternative new technologies for contaminants recognition and removal

    NARCIS (Netherlands)

    Lotfi, S.; Di Maio, F.; Xia, H.; Serranti, S.; Palmieri, R.; Bonifazi, G.

    2015-01-01

    One of the main challenging problems associated with the use of Recycled Aggregates (RA) is the level of mixed contaminants. For utilizing RA in high-grade applications, it is essential to monitor and minimise the content of the pollutants. To this extent the C2CA concrete recycling process

  6. Assessment of the contaminants level in recycled aggregates and alternative new technologies for contaminants recognition and removal

    NARCIS (Netherlands)

    Lotfi, S.; Di Maio, F.; Xia, H.; Serranti, S.; Palmieri, R.; Bonifazi, G.

    2015-01-01

    One of the main challenging problems associated with the use of Recycled Aggregates (RA) is the level of mixed contaminants. For utilizing RA in high-grade applications, it is essential to monitor and minimise the content of the pollutants. To this extent the C2CA concrete recycling process investig

  7. Assessment of the contaminants level in recycled aggregates and alternative new technologies for contaminants recognition and removal

    NARCIS (Netherlands)

    Lotfi, S.; Di Maio, F.; Xia, H.; Serranti, S.; Palmieri, R.; Bonifazi, G.

    2015-01-01

    One of the main challenging problems associated with the use of Recycled Aggregates (RA) is the level of mixed contaminants. For utilizing RA in high-grade applications, it is essential to monitor and minimise the content of the pollutants. To this extent the C2CA concrete recycling process investig

  8. COMBINATION OF A SOURCE REMOVAL REMEDY AND BIOREMEDIATION FOR THE TREATMENT OF A TCE CONTAMINATED AQUIFER

    Science.gov (United States)

    Historical disposal practices of chlorinated solvents have resulted in the widespread contamination of ground-water resources. These ground-water contaminants exist in the subsurface as free products, residual and vapor phases, and in solution. The remediation of these contamin...

  9. Improved removal of sticky and light contaminants from wastepaper. Final report, April 1, 1995--December 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, P.; Kelly, A.

    1998-03-01

    Work under this two-year cooperative agreement addresses improved removal of light and sticky contaminants from waste paper. Such contaminants occur in ever-increasing amounts, resulting from glues, labels, book bindings, packaging tapes, etc., all associated with the waste paper stream. Despite various cleaning steps in the paper mill recycling systems, residual contamination remains, causing big problems with the product quality and with paper machine and converting operations. Some grades cannot be recycled at all. Stickies are truly a barrier against increased paper recycling. The stickies problem was attacked in four project segments--three of those have yielded tangible results. One segment has been outstanding in its success; namely, the development of a centrifugal reverse cleaning system consisting of primary and secondary stages, which have unparalleled high efficiency in the removal of light and sticky contaminants. This cleaning system, consists of primary XTREME and secondary XX-Clone units. Another segment of this work, washing wax contaminated old corrugated wastepaper (OCC), also has resulted in the new Xtrax process which was released for sale.

  10. Novel low-cost approach for removal of surface contamination before texturization of commercial monocrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gangopadhyay, U. [Electronics and Telecommunication Engineering Department, IC Design and Fabrication Centre, Jadavpur University, Kolkata 700032 (India); School of Information and Communication Engineering, Sungkyunkwan University, 300, Chun-Chun dong, Jangan-gu, Suwon, 440-746 (Korea); Dhungel, S.K.; Yi, J. [School of Information and Communication Engineering, Sungkyunkwan University, 300, Chun-Chun dong, Jangan-gu, Suwon, 440-746 (Korea); Mondal, A.K. [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 71103 (India); Saha, H. [Electronics and Telecommunication Engineering Department, IC Design and Fabrication Centre, Jadavpur University, Kolkata 700032 (India)

    2007-07-23

    This paper reports a novel approach on the surface treatment of monocrystalline silicon solar cells using an inorganic chemical, sodium hypochlorite (NaOCl) that has some remarkable properties. The treatment of contaminated crystalline silicon wafer with hot NaOCl helps the removal of organic contaminants due to its oxidizing properties. The objective of this paper is to establish the effectiveness of this treatment using hot NaOCl solution before the saw damage removal step of the conventional NaOH texturing approach. A comparative study of surface morphology and FTIR analyses of textured monocrystalline silicon surfaces with and without NaOCl pre-treatment is also reported. The process could result in a significant low cost approach viable for cleaning silicon wafers on a mass production scale. (author)

  11. Simultaneous removal of selected oxidized contaminants in groundwater using a continuously stirred hydrogen-based membrane biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    Siqing Xia; Jun Liang; Xiaoyin Xu; Shuang Shen

    2013-01-01

    A laboratory trial was conducted for evaluating the capability of a continuously stirred hydrogen-based membrane biofilm reactor to simultaneously reduce nitrate (NO3--N),sulfate (SO42-),bromate (BrO3-),hexavalent chromium (Cr(Ⅵ)) and parachloronitrobenzene (p-CNB).The reactor contained two bundles of hollow fiber membranes functioning as an autotrophic biofilm carrier and hydrogen pipe as well.On the condition that hydrogen was supplied as electron donor and diffused into water through membrane pores,autohydrogenotrophic bacteria were capable of reducing contaminants to forms with lower toxicity.Reduction occurred within 1 day and removal fluxes for NO3--N,SO42-,BrO3-,Cr(Ⅵ),and p-CNB reached 0.641,2.396,0.008,0.016 and 0.031 g/(day.m2),respectively after 112 days of continuous operation.Except for the fact that sulfate was 37% removed under high surface loading,the other four contaminants were reduced by over 95%.The removal flux comparison between phases varying in surface loading and H2 pressure showed that decreasing surface loading or increasing H2 pressure would promote removal flux.Competition for electrons occurred among the five contaminants.Electron-equivalent flux analysis showed that the amount of utilized hydrogen was mainly controlled by NO2--N and SO42-reduction,which accounted for over 99% of the electron flux altogether.It also indicated the electron acceptor order,showing that nitrate was the most prior electron acceptor while sulfate was the second of the five contaminants.

  12. Clean water from clean energy: removal of dissolved contaminants from brackish groundwater using wind energy powered electrodialysis

    OpenAIRE

    Malek, Payam

    2015-01-01

    Around 770 million people lack access to improved drinking water sources (WHO 2013), urgently necessitating implementation of contaminant removal by e.g. desalination systems on a large scale. To improve water quality and enable use of brackish water sources for human consumption in remote arid areas, a directly coupled wind – electrodialysis system (Wind-ED) was developed. Modularity, sustainability and above all suitability for the practical use in off-grid locations were ...

  13. Seasonal variations in fate and removal of trace organic chemical contaminants while operating a full-scale membrane bioreactor.

    Science.gov (United States)

    Trinh, Trang; van den Akker, Ben; Coleman, Heather M; Stuetz, Richard M; Drewes, Jörg E; Le-Clech, Pierre; Khan, Stuart J

    2016-04-15

    Trace organic chemical (TrOC) contaminants are of concern for finished water from water recycling schemes because of their potential adverse environmental and public health effects. Understanding the impacts of seasonal variations on fate and removal of TrOCs is important for proper operation, risk assessment and management of treatment systems for water recycling such as membrane bioreactors (MBRs). Accordingly, this study investigated the fate and removal of a wide range of TrOCs through a full-scale MBR plant during summer and winter seasons. TrOCs included 12 steroidal hormones, 3 xeno-estrogens, 2 pesticides and 23 pharmaceuticals and personal care products. Seasonal differences in the mechanisms responsible for removing some of the TrOCs were evident. In particular the contribution of biotransformation and biomass adsorption to the overall removal of estrone, bisphenol A, 17β-estradiol and triclosan were consistently different between the two seasons. Substantially higher percentage removal via biotransformation was observed during the summer sampling period, which compensated for a reduction in removal attributed to biomass adsorption. The opposite was observed during winter, where the contribution of biotransformation to the overall removal of these TrOCs had decreased, which was offset by an improvement in biomass adsorption. The exact mechanisms responsible for this shift are unknown, however are likely to be temperature related as warmer temperatures can lower sorption efficiency, yet enhance biotransformation of these TrOCs.

  14. Removal of Volatile Organic Contaminants via Low Profile Aeration Technology (WaterRF Report 4439)

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) is considering a change in the way contaminants are regulated as a part of their new drinking water strategy (DWS). The strategy will regulate contaminants as groups rather than individually. The first group consists of 16 VOCs, and ...

  15. Evidence based decontamination protocols for the removal of external Δ9-tetrahydrocannabinol (THC) from contaminated hair

    NARCIS (Netherlands)

    Duvivier, W.F.; Peeters, R.J.; Beek, van T.A.; Nielen, M.W.F.

    2016-01-01

    External contamination can cause false positive results in forensic hair testing for drugs of abuse and is therefore a major concern when hair evidence is used in court. Current literature about decontamination strategies is mainly focused on external cocaine contamination and no consensus on the be

  16. Removal of heavy metals from contaminated sewage sludge using Aspergillus niger fermented raw liquid from pineapple wastes.

    Science.gov (United States)

    Del Mundo Dacera, Dominica; Babel, Sandhya

    2008-04-01

    The environmental benefits derived from using citric acid in the removal of heavy metals from contaminated sewage sludge have made it promising as an extracting agent in the chemical extraction process. At present, citric acid is produced commercially by fermentation of sucrose using mutant strains of Aspergillus niger (A. niger), and chemical synthesis. In recent years, various carbohydrates and wastes (such as pineapple wastes) have been considered experimentally, to produce citric acid by A. niger. This study investigated the potential of using A. niger fermented raw liquid from pineapple wastes as a source of citric acid, in extracting chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) from anaerobically digested sewage sludge. Results of the study revealed that metal removal efficiencies varied with pH, forms of metals in sludge and contact time. At pH approaching 4, and contact time of 11 days, A. niger fermented liquid seemed to remove all Cr and Zn while removing 94% of Ni. Moreover, chemical speciation studies revealed that metals which are predominantly in the exchangeable and oxidizable phases seemed to exhibit ease of leachability (e.g., Zn). The by-products of the process such as pineapple pulp and mycelium which are rich in protein, can still be used as animal feed. It can be said therefore that this novel process provides a sustainable way of managing contaminated sewage sludge.

  17. Removal of uranium from uranium-contaminated soils -- Phase 1: Bench-scale testing. Uranium in Soils Integrated Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Francis, C. W.

    1993-09-01

    To address the management of uranium-contaminated soils at Fernald and other DOE sites, the DOE Office of Technology Development formed the Uranium in Soils Integrated Demonstration (USID) program. The USID has five major tasks. These include the development and demonstration of technologies that are able to (1) characterize the uranium in soil, (2) decontaminate or remove uranium from the soil, (3) treat the soil and dispose of any waste, (4) establish performance assessments, and (5) meet necessary state and federal regulations. This report deals with soil decontamination or removal of uranium from contaminated soils. The report was compiled by the USID task group that addresses soil decontamination; includes data from projects under the management of four DOE facilities [Argonne National Laboratory (ANL), Los Alamos National Laboratory (LANL), Oak Ridge National Laboratory (ORNL), and the Savannah River Plant (SRP)]; and consists of four separate reports written by staff at these facilities. The fundamental goal of the soil decontamination task group has been the selective extraction/leaching or removal of uranium from soil faster, cheaper, and safer than current conventional technologies. The objective is to selectively remove uranium from soil without seriously degrading the soil`s physicochemical characteristics or generating waste forms that are difficult to manage and/or dispose of. Emphasis in research was placed more strongly on chemical extraction techniques than physical extraction techniques.

  18. The Effect of the Cool Intense Pulsed Light (CIPL on Hair Removal of Chin Area in Hirsute Women

    Directory of Open Access Journals (Sweden)

    SH Njafei Dolatabadi

    2012-12-01

    Full Text Available Abstract Background & aim: Hirsutism can esthetically cause significant psychosocial consequences in hirsute women. Different methods, so far, have been applied for hair removal, and the Cool Intense Pulsed Light (CIPL system is one of them. The aim of this study was to determine the effect and side effects of the CIPL method on removing the hairs of the chin area in hirsute women. Methods: This is a interventional study in which 30 women suffering from hirsutism referred to a dermatologist's clinic in Yasuj, Iran were participated during 2009-2010. A convenience sampling method was used for data collection. Subjects underwent the Cool Intense Pulsed Light method over 6 months, one session per month . To compare the effect of the applied intervention, number of hair on the chin area were compared before and after the intervention Collected data were analyzed by the SPSS software using descriptive and analytic statistics such as t-test, paired t-test and ANOVA, considering α=0.05. Results: The duration of affliction with hirsutism was 1-15 year. The mean number of hairs of the chin area before and after the intervention were 288.2± 229.2 and 56.4± 43.8 respectively. Paired T-test analysis revealed that the difference is significant (p=0.001. None of the participants reported any specific problems related to the applied intervention. Conclusion: treatment efficacy of CIPL for hirsutism was 80 percent. However, we suggest further studies to confirm these findings. Key words: Cool Intense Pulsed Light, Hirsutism, Hair removal

  19. Emerging contaminants from industrial and municipal waste. Pt. 2. Removal technologies

    Energy Technology Data Exchange (ETDEWEB)

    Barcelo, Damia; Petrovic, Mira (eds.) [IIQAB - CSIC, Barcelona (Spain). Dept. of Environmental Chemistry

    2008-07-01

    The group of non-regulated contaminants termed 'emerging contaminants' mainly comprises products used in large quantities in everyday life, such as human and veterinary pharmaceuticals, personal care products, surfactants and surfactant residues, plasticizers and various industrial additives. The occurrence of 'emerging contaminants' in wastewaters, and their behavior during wastewater treatment and production of drinking water are key issues in the re-use of water resources. Emerging Contaminants from Industrial and Municipal Waste focuses on innovative treatment technologies for the elimination of emerging contaminants from wastewater and drinking water. The respective treatment processes, such as membrane bioreactors, photocatalysis, ozonation and advanced oxidation are dealt with in detail. The book also discusses sources and occurrence of emerging contaminants in municipal and industrial waste, giving a concise and critical overview of state-of-the-art analytical methods for their identification. Further important aspects covered by the book include the acute and chronic effects and overall impact of emerging contaminants on the environment. (orig.)

  20. Slag characterization and removal using pulse detonation for coal gasification. Quarterly research report, July 1--September 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Z.; Mei, D.; Biney, P.O.; Zhou, J.; Ali, M.R.

    1996-10-25

    Boiler slagging and fouling as a result of inorganic impurities in combustion gases being deposited on heat transfer tubes have caused severe problems in coal-fired power plant operation. These problems are fuel, system design, and operating condition dependent. Conventional slag and ash removal methods include the use of in situ blowing or jet-type devices such as air or steam soot blowers and water lances. Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. The detonation wave technique based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. These detonation waves have been demonstrated experimentally to have exceptionally high shearing capability important to the task of removing slag and fouling deposits. Several tests have been performed with single shot detonation wave at University of Texas at Arlington to remove the slag deposit. To hold the slag deposit samples at the exit of detonation tube, two types of fixture was designed and fabricated. They are axial arrangement and triangular arrangement. The slag deposits from the utility boilers have been used to prepare the slag samples for the test. The experimental results show that the single shot detonation wave is capable of removing the entire slag (types of slag deposited on economizer, and air-heater, i.e., relatively softer slags) and 30% of the reheater slag (which is harder) even at a distance of 6 in. from the exit of a detonation engine tube. Wave strength and slag orientation also have different effects on the chipping off of the slag. The annual report discusses about the results obtained in effectively removing the slag.

  1. Remediation of the Highland Drive South Ravine, Port Hope, Ontario: Contaminated Groundwater Discharge Management Using Permeable Reactive Barriers and Contaminated Sediment Removal - 13447

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, David; Roos, Gillian [Golder Associates Ltd., 2390 Argentia Road, Mississauga, ON L5N 5Z7 (Canada); Ferguson Jones, Andrea [MMM Group Ltd., 100 Commerce Valley Drive West, Thornhill, ON L3T 0A1 (Canada); Case, Glenn [AECL Port Hope Area Initiative Management Office, 115 Toronto Road, Port Hope, ON L1A 3S4 (Canada); Yule, Adam [Public Works and Government Services Canada, 4900 Yonge Street, 11th Floor, Toronto, ON, M2N 6A6 (Canada)

    2013-07-01

    The Highland Drive South Ravine (HDSR) is the discharge area for groundwater originating from the Highland Drive Landfill, the Pine Street North Extension (PSNE) roadbed parts of the Highland Drive roadbed and the PSNE Consolidation Site that contain historical low-level radioactive waste (LLRW). The contaminant plume from these LLRW sites contains elevated concentrations of uranium and arsenic and discharges with groundwater to shallow soils in a wet discharge area within the ravine, and directly to Hunt's Pond and Highland Drive South Creek, which are immediately to the south of the wet discharge area. Remediation and environmental management plans for HDSR have been developed within the framework of the Port Hope Project and the Port Hope Area Initiative. The LLRW sites will be fully remediated by excavation and relocation to a new Long-Term Waste Management Facility (LTWMF) as part of the Port Hope Project. It is projected, however, that the groundwater contaminant plume between the remediated LLRW sites and HDSR will persist for several hundreds of years. At the HDSR, sediment remediation within Hunt's Ponds and Highland Drive South Creek, excavation of the existing and placement of clean fill will be undertaken to remove current accumulations of solid-phase uranium and arsenic associated with the upper 0.75 m of soil in the wet discharge area, and permeable reactive barriers (PRBs) will be used for in situ treatment of contaminated groundwater to prevent the ongoing discharge of uranium and arsenic to the area in HDSR where shallow soil excavation and replacement has been undertaken. Bench-scale testing using groundwater from HDSR has confirmed excellent treatment characteristics for both uranium and arsenic using permeable reactive mixtures containing granular zero-valent iron (ZVI). A sequence of three PRBs containing ZVI and sand in backfilled trenches has been designed to intercept the groundwater flow system prior to its discharge to the ground

  2. Cardiovascular changes after PMMA vertebroplasty in sheep: the effect of bone marrow removal using pulsed jet-lavage.

    Science.gov (United States)

    Benneker, Lorin M; Krebs, Jörg; Boner, Vanessa; Boger, Andreas; Hoerstrup, Simon; Heini, Paul F; Gisep, Armando

    2010-11-01

    Clinically, the displacement of intravertebral fat into the circulation during vertebroplasty is reported to lead to problems in elderly patients and can represent a serious complication, especially when multiple levels have to be treated. An in vitro study has shown the feasibility of removing intravertebral fat by pulsed jet-lavage prior to vertebroplasty, potentially reducing the embolization of bone marrow fat from the vertebral bodies and alleviating the cardiovascular changes elicited by pulmonary fat embolism. In this in vivo study, percutaneous vertebroplasty using polymethylmethacrylate (PMMA) was performed in three lumbar vertebrae of 11 sheep. In six sheep (lavage group), pulsed jet-lavage was performed prior to injection of PMMA compared to the control group of five sheep receiving only PMMA vertebroplasty. Invasive recording of blood pressures was performed continuously until 60 min after the last injection. Cardiac output and arterial blood gas parameters were measured at selected time points. Post mortem, the injected cement volume was measured using CT and lung biopsies were processed for assessment of intravascular fat. Pulsed jet-lavage was feasible in the in vivo setting. In the control group, the injection of PMMA resulted in pulmonary fat embolism and a sudden and significant increase in mean pulmonary arterial pressure. Pulsed jet-lavage prevented any cardiovascular changes and significantly reduced the severity of bone marrow fat embolization. Even though significantly more cement had been injected into the lavaged vertebral bodies, significantly fewer intravascular fat emboli were identified in the lung tissue. Pulsed jet-lavage prevented the cardiovascular complications after PMMA vertebroplasty in sheep and alleviated the severity of pulmonary fat embolism.

  3. Assessment of the mechanisms involved in the removal of emerging contaminants by microalgae from wastewater: a laboratory scale study

    Energy Technology Data Exchange (ETDEWEB)

    Matamoros, Víctor, E-mail: victor.matamoros@idaea.csic.es [Department of Environmental Chemistry, IDAEA–CSIC, c/Jordi Girona, 18-26, E-08034 Barcelona (Spain); Uggetti, Enrica; García, Joan [GEMMA—Group of Environmental Engineering and Microbiology, Department of Hydraulic, Maritime and Environmental Engineering, Universitat Politècnica de Catalunya BarcelonaTech, c/Jordi Girona, 1-3, Building D1, E-08034 Barcelona (Spain); Bayona, Josep M. [Department of Environmental Chemistry, IDAEA–CSIC, c/Jordi Girona, 18-26, E-08034 Barcelona (Spain)

    2016-01-15

    Highlights: • The effect of microalage on the removal of emerging contaminants has been evaluated. • Volatilization was relevant for compounds with a moderate Henry’s law constant. • Biodegradation was the main factor for the removal of caffeine and ibuprofen. • Ibuprofen enantioselective biodegradation was observed. • CA-ibuprofen and OH-ibuprofen followed the concentration decline of ibuprofen. - Abstract: Aerated batch reactors (2.5 L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d{sup −1} with the complete removal of N-NH{sub 4} during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry’s law constant higher than 3 10{sup −1} Pa m{sup 3} mol{sup −1} (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.

  4. Use of fugacity model to analyze temperature-dependent removal of micro-contaminants in sewage treatment plants.

    Science.gov (United States)

    Thompson, Kelly; Zhang, Jianying; Zhang, Chunlong

    2011-08-01

    Effluents from sewage treatment plants (STPs) are known to contain residual micro-contaminants including endocrine disrupting chemicals (EDCs) despite the utilization of various removal processes. Temperature alters the efficacy of removal processes; however, experimental measurements of EDC removal at various temperatures are limited. Extrapolation of EDC behavior over a wide temperature range is possible using available physicochemical property data followed by the correction of temperature dependency. A level II fugacity-based STP model was employed by inputting parameters obtained from the literature and estimated by the US EPA's Estimations Programs Interface (EPI) including EPI's BIOWIN for temperature-dependent biodegradation half-lives. EDC removals in a three-stage activated sludge system were modeled under various temperatures and hydraulic retention times (HRTs) for representative compounds of various properties. Sensitivity analysis indicates that temperature plays a significant role in the model outcomes. Increasing temperature considerably enhances the removal of β-estradiol, ethinyestradiol, bisphenol, phenol, and tetrachloroethylene, but not testosterone with the highest biodegradation rate. The shortcomings of BIOWIN were mitigated by the correction of highly temperature-dependent biodegradation rates using the Arrhenius equation. The model predicts well the effects of operating temperature and HRTs on the removal via volatilization, adsorption, and biodegradation. The model also reveals that an impractically long HRT is needed to achieve a high EDC removal. The STP model along with temperature corrections is able to provide some useful insight into the different patterns of STP performance, and useful operational considerations relevant to EDC removal at winter low temperatures. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. A Nanoparticulate Photocatalytic Filter for Removal of Trace Contaminant Gases Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Maintaining a healthy atmosphere in closed life support systems is essential for crew well being and success of space missions. Current trace contaminant control...

  6. A Nanoparticulate Photocatalytic Filter for Removal of Trace Contaminant Gases Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Maintaining a healthy atmosphere in closed life support systems is necessary for the well being of the crew and success of a space mission. Current trace contaminant...

  7. Removal of Pesticides and Inorganic Contaminants in Anaerobic and Aerobic Biological Contactors

    Science.gov (United States)

    This presentation contains data on the removal of pesticides (acetochlor, clethodim, dicrotophos), ammonia, nitrate, bromate and perchlorate through aerobic and anaerobic biological treatment processes.

  8. Treatment technologies used for the removal of As, Cr, Cu, PCP and/or PCDD/F from contaminated soil: A review.

    Science.gov (United States)

    Guemiza, Karima; Coudert, Lucie; Metahni, Sabrine; Mercier, Guy; Besner, Simon; Blais, Jean-François

    2017-07-05

    The contamination of soils by metals such as arsenic, chromium, copper and organic compounds such as pentachlorophenol (PCP) and dioxins and furans (PCDD/F) is a major problem in industrialized countries. Excavation followed by disposal in an appropriate landfilling is usually used site to manage these contaminated soils. Many researches have been conducted to develop physical, biological, thermal and chemical methods to allow the rehabilitation of contaminated sites. Thermal treatments including thermal desorption seemed to be the most appropriate methods, allowing the removal of more than 99.99% of organic contaminants but, they are ineffective for inorganic compounds. Biological treatments have been developed to remove inorganic and hydrophobic organic contaminants but their applications are limited to soils contaminated by easily biodegradable organic compounds. Among the physical technologies available, attrition is the most commonly used technique for the rehabilitation of soils contaminated by both organic and inorganic contaminants. Chemical processes using acids, bases, redox agents and surfactants seemed to be an interesting option to simultaneously extract organic and inorganic contaminants from soils. This paper will provide an overview of the recent developments in the field of decontamination technologies applicable for the removal of As, Cr, Cu, PCP and/or PCDD/F from contaminated soils. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Shadowgraphic imaging of material removal during laser drilling with a long pulse eximer laser

    NARCIS (Netherlands)

    Schoonderbeek, A.; Biesheuvel, C.A.; Hofstra, R.M.; Boller, Klaus J.; Meijer, J.

    2005-01-01

    After the development of a novel XeCl excimer laser with a nearly diffraction-limited beam and 175 ns pulse length, research was done on different industrial applications of this laser. Hole drilling, one of these applications, was studied extensively. A better understanding of the drilling process

  10. The intense pulsed light systems : new treatment possibilities for vascular, pigmented lesions and hair removal

    NARCIS (Netherlands)

    C.A. Schroeter (Careen)

    2004-01-01

    textabstractGiven all of the differences in between laser and IPLS devices and the need for additional information in IPLS treatment applications, the aim of this study was to evaluate new treatment possibilities using Intense Pulsed Light Sources and to address the following questions: 1. What are

  11. Supported Photocatalyst for Removal of Emerging Contaminants from Wastewater in a Continuous Packed-Bed Photoreactor Configuration

    Directory of Open Access Journals (Sweden)

    Mª Emma Borges

    2015-02-01

    Full Text Available Water pollution from emerging contaminants (ECs or emerging pollutants is an important environmental problem. Heterogeneous photocatalytic treatment, as advanced oxidation treatment of wastewater effluents, has been proposed to solve this problem. In this paper, a heterogeneous photocatalytic process was studied for emergent contaminants removal using paracetamol as a model contaminant molecule. TiO2 photocatalytic activity was evaluated using two photocatalytic reactor configurations: Photocatalyst solid suspension in wastewater in a stirred photoreactor and TiO2 supported on glass spheres (TGS configuring a packed bed photoreactor. The surface morphology and texture of the TGS were monitored by scanning electron microscope (SEM. The influence of photocatalyst amount and wastewater pH were evaluated in the stirred photoreactor and the influence of wastewater flowrate was tested in the packed bed photoreactor, in order to obtain the optimal operation conditions. Moreover, results obtained were compared with those obtained from photolysis and adsorption studies, using the optimal operation conditions. Good photocatalytic activities have been observed and leads to the conclusion that the heterogeneous photocatalytic system in a packed bed is an effective method for removal of emerging pollutants.

  12. Comparative study of NO removal in surface-plasma and volume-plasma reactors based on pulsed corona discharges.

    Science.gov (United States)

    Malik, Muhammad Arif; Kolb, Juergen F; Sun, Yaohong; Schoenbach, Karl H

    2011-12-15

    Nitric oxide (NO) conversion has been studied for two different types of atmospheric-pressure pulsed-corona discharges, one generates a surface-plasma and the other provides a volume-plasma. For both types of discharges the energy cost for NO removal increases with decreasing oxygen concentration and initial concentration of NO. However, the energy cost for volume plasmas for 50% NO removal, EC(50), from air was found to be 120 eV/molecule, whereas for the surface plasma, it was only 70 eV/molecule. A smaller difference in energy cost, but a higher efficiency for removal of NO was obtained in a pure nitrogen atmosphere, where NO formation is restricted due to the lack of oxygen. For the volume plasma, EC(50) in this case was measured at 50 eV/molecule, and for the surface plasma it was 40 eV/molecule. Besides the higher NO removal efficiency of surface plasmas compared to volume plasmas, the energy efficiency of surface-plasmas was found to be almost independent of the amount of electrical energy deposited in the discharge, whereas the efficiency for volume plasmas decreases considerably with increasing energy. This indicates the possibility of operating surface plasma discharges at high energy densities and in more compact reactors than conventional volume discharges.

  13. Comparative study of NO removal in surface-plasma and volume-plasma reactors based on pulsed corona discharges

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Muhammad Arif, E-mail: MArifMalik@gmail.com [Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA 23508 (United States); Kolb, Juergen F.; Sun, Yaohong; Schoenbach, Karl H. [Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA 23508 (United States)

    2011-12-15

    Nitric oxide (NO) conversion has been studied for two different types of atmospheric-pressure pulsed-corona discharges, one generates a surface-plasma and the other provides a volume-plasma. For both types of discharges the energy cost for NO removal increases with decreasing oxygen concentration and initial concentration of NO. However, the energy cost for volume plasmas for 50% NO removal, EC{sub 50}, from air was found to be 120 eV/molecule, whereas for the surface plasma, it was only 70 eV/molecule. A smaller difference in energy cost, but a higher efficiency for removal of NO was obtained in a pure nitrogen atmosphere, where NO formation is restricted due to the lack of oxygen. For the volume plasma, EC{sub 50} in this case was measured at 50 eV/molecule, and for the surface plasma it was 40 eV/molecule. Besides the higher NO removal efficiency of surface plasmas compared to volume plasmas, the energy efficiency of surface-plasmas was found to be almost independent of the amount of electrical energy deposited in the discharge, whereas the efficiency for volume plasmas decreases considerably with increasing energy. This indicates the possibility of operating surface plasma discharges at high energy densities and in more compact reactors than conventional volume discharges.

  14. In situ biosurfactant production and hydrocarbon removal by Pseudomonas putida CB-100 in bioaugmented and biostimulated oil-contaminated soil

    Directory of Open Access Journals (Sweden)

    Martínez-Toledo Ángeles

    2013-01-01

    Full Text Available In situ biosurfactant (rhamnolipid production by Pseudomonas putida CB-100 was achieved during a bioaugmented and biostimulated treatment to remove hydrocarbons from aged contaminated soil from oil well drilling operations. Rhamnolipid production and contaminant removal were determined for several treatments of irradiated and non-irradiated soils: nutrient addition (nitrogen and phosphorus, P. putida addition, and addition of both (P. putida and nutrients. The results were compared against a control treatment that consisted of adding only sterilized water to the soils. In treatment with native microorganisms (non-irradiated soils supplemented with P. putida, the removal of total petroleum hydrocarbons (TPH was 40.6%, the rhamnolipid production was 1.54 mg/kg, and a surface tension of 64 mN/m was observed as well as a negative correlation (R = -0.54; p < 0.019 between TPH concentration (mg/kg and surface tension (mN/m, When both bacteria and nutrients were involved, TPH levels were lowered to 33.7%, and biosurfactant production and surface tension were 2.03 mg/kg and 67.3 mN/m, respectively. In irradiated soil treated with P. putida, TPH removal was 24.5% with rhamnolipid generation of 1.79 mg/kg and 65.6 mN/m of surface tension, and a correlation between bacterial growth and biosurfactant production (R = -0.64; p < 0.009 was observed. When the nutrients and P. putida were added, TPH removal was 61.1%, 1.85 mg/kg of biosurfactants were produced, and the surface tension was 55.6 mN/m. In summary, in irradiated and non-irradiated soils, in situ rhamnolipid production by P. putida enhanced TPH decontamination of the soil.

  15. Removal of PAHs from contaminated calyey soil by means of electro-osmosis

    NARCIS (Netherlands)

    Lima, A.T.; Kleingeld, P.J.; Heister, K.; Loch, J.P.G.

    2011-01-01

    The removal of polycyclic aromatic hydrocarbons (PAHs) from clayey soils is an intricate task. The low porosity of compacted clayey soil hinders bacterial activity and makes convective removal by hydraulic flow impossible. Electro-osmosis is a process that has been used for the mobilization and clea

  16. Removal of PAHs from contaminated calyey soil by means of electro-osmosis

    NARCIS (Netherlands)

    Lima, A.T.; Kleingeld, P.J.; Heister, K.; Loch, J.P.G.

    2011-01-01

    The removal of polycyclic aromatic hydrocarbons (PAHs) from clayey soils is an intricate task. The low porosity of compacted clayey soil hinders bacterial activity and makes convective removal by hydraulic flow impossible. Electro-osmosis is a process that has been used for the mobilization and

  17. Removal of heavy metals and arsenic from a co-contaminated soil by sieving combined with washing process.

    Science.gov (United States)

    Liao, Xiaoyong; Li, You; Yan, Xiulan

    2016-03-01

    Batch experiments were conducted with a heavy metals and arsenic co-contaminated soil from an abandoned mine to evaluate the feasibility of a remediation technology that combines sieving with soil washing. Leaching of the arsenic and heavy metals from the different particle size fractions was found to decrease in the order: 2mm. With increased contact time, the concentration of heavy metals in the leachate was significantly decreased for small particles, probably because of adsorption by the clay soil component. For the different particle sizes, the removal efficiencies for Pb and Cd were 75%-87%, and 61%-77% for Zn and Cu, although the extent of removal was decreased for As and Cr at soil particles >2mm, although good metal removal efficiencies were also achieved in the small particle size fractions. Through SEM-EDS observations and correlation analysis, the leaching regularity of the heavy metals and arsenic was found to be closely related to Fe, Mn, and Ca contents of the soil fractions. The remediation of heavy metal-contaminated soil by sieving combined with soil washing was proven to be efficient, and practical remediation parameters were also recommended.

  18. Clinical usefulness of transpapillary removal of common bile duct stones by frequency doubled double pulse Nd: YAG laser

    Institute of Scientific and Technical Information of China (English)

    Tae Hyeon Kim; Hyo Jeong Oh; Chang-Soo Choi; Dong Han Yeom; Suck Chei Choi

    2008-01-01

    AIM: To study the efficacy and the safety of laser lithotripsy without direct visual control by using a balloon catheter in patients with bile duct stones that could not be extracted by standard technique.METHODS: The seventeen patients (7 male and 10 female; mean age 67.8 years) with difficult common bile duct (CBD) stones were not amenable for conventional endoscopic maneuvers such as sphincterotomy and mechanical lithotripsy were included in this study. Laser wavelengths of 532 nm and 1064 nm as a double pulse were applied with pulse energy of 120 mJ. The laser fiber was advanced under fluoroscopic control through the ERCP balloon catheter. Laser lithotripsy was continued until the fragment size seemed to be less than 10 mm.Endoscopic extraction of the stones and fragments was performed with the use of the Dormia basket and balloon catheter.RESULTS: Bile duct clearance was achieved in 15 of 17 patients (88%). The mean number of treatment sessions was 1.7 ± 0.6. Endoscopic stone removal could not be achieved in 2 patients (7%). Adverse effects were noted in three patients (hemobilia, pancreatitis, and cholangitis).CONCLUSION: The Frequency Doubled Double Pulse Nd:YAG (FREDDY) laser may be an effective and safe technique in treatment of difficult bile duct stones.

  19. Covalent organic polymer functionalized activated carbon: A novel material for water contaminant removal and CO2 capture

    DEFF Research Database (Denmark)

    Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

    Covalent organic polymers (COPs) have emerged as one of the leading advanced materials for environmental applications, such as the capture and recovery of carbon dioxide and the removal of contaminants from polluted water. COPs exhibit many remarkable properties that other leading advanced...... uptake in concentrated streams to metal and organic pollutant adsorption in contaminated waters. However, given the nanoscale structure of these COPs, real-world application has yet remained elusive for these materials. Herein, we report the functionalization of COPs onto the surface of activated carbon...... of COPs onto a material large enough to be able to be used in a packed-bed column. These columns can then be applied to the exhaust flue gas stream from a power plant or as a flow-through water treatment column. Furthermore, by impregnating nanoscale zero valent iron (nZVI) inside the COP matrix...

  20. Simultaneous removal of co-contaminants: acid brilliant violet and Cu2+ by functional bimetallic Fe/Pd nanoparticles

    Science.gov (United States)

    Jin, Xiaoying; Chen, Zhengxian; Wang, Ting; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

    2014-10-01

    Effluents from the textile industry often contain dyes and metals that are a serious environmental concern. It is a challenge to develop a method for simultaneous removal of mixed contaminants. In this study, kaolinite supported bimetallic Fe/Pd (K-Fe/Pd) is firstly reported to be used for simultaneous catalytic removal of acid brilliant violet (ABV) and Cu2+ in aqueous solution, where the presence of kaolinite as a stable supporter and disperser maintains the reactivity of Fe0 as a reductant, while Pd0 as a catalyst accelerates the reaction. This was confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and batch experiments. 96.23 % of ABV and 100 % of Cu2+ was removed using K-Fe/Pd within 60 min, while only 77.50 % of ABV and 99.45 % of Cu2+ using K-Fe, and 19.75 % of ABV and 4.00 % of Cu2+ using kaolinite was removed, respectively. However, both efficiency and rate of removal in the mixed solution were higher than that of the single one regarding both ABV and Cu2+, which is attributable to the formation of in situ trimetallic Cu/Fe/Pd in the mixed solution. Different factors impacting on the removal of ABV-Cu2+ using K-Fe/Pd showed that the catalytic reduction decreased when pH, initial concentration, and temperature increased. Finally, the reuse and application of K-Fe/Pd in dyeing wastewater led to a removal efficiency of 96.35 % for ABV and 100 % for Cu2+, respectively.

  1. Material removal during double-pulsed (ms and ns) laser drilling

    Science.gov (United States)

    Wang, Zicheng; Qin, Yuan; Yang, Sen; Shi, Bang; Wang, Heming; Chen, Hanyu

    2017-05-01

    Laser drilling is one of the processing approaches in aerospace industry. However, drilling with ms laser is unstable since the drilled hole is easy to be blocked by re-solidified molten material. To solve this problem, two different pulsed lasers (millisecond and nanosecond) are used in our experiments. The shock wave produced by the ns laser is introduced to increase the migration mass. With the help of shock wave, the depth and quality of the hole get higher. The influences of the interval time, the ms laser energy and the laser pulse duration time on the quality of drilled holes are also discussed. The results show that the hole is deep and clean if the ns laser is added shortly after the beginning of ms laser. The ms laser energy and the laser duration time determine the depth of the hole.

  2. Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder

    Science.gov (United States)

    Ormesher, Richard C.; Axline, Robert M.

    2008-12-02

    Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.

  3. Cadmium accumulation characteristics and removal potentials of high cadmium accumulating rice line grown in cadmium-contaminated soils.

    Science.gov (United States)

    Tang, Hao; Li, Tingxuan; Yu, Haiying; Zhang, Xizhou

    2016-08-01

    Phytoextraction is a promising technique to remove cadmium (Cd) from contaminated soils. In this research, the two different Cd accumulation rice lines of Lu527-8 (the high Cd accumulating rice line) and Lu527-4 (the normal rice line) were grown in soils with different Cd treatments (0, 5, 10, and 20 mg kg(-1) soil) to evaluate Cd accumulation characteristics and Cd removal potentials. When the concentration of Cd in soil increased, Lu527-8 showed less symptoms of phytotoxicity when compared to Lu527-4. Furthermore, Lu527-8 demonstrated greater shoot Cd accumulation (321.17-964.95 mg plant(-1)) than Lu527-4 (50.37-201.66 μg plant(-1)) at the jointing and filling stages. The soil available Cd content of Lu527-8 significantly decreased by 26.92-38.97 and 27.77-63.44 % at the jointing and filling stages, respectively. Meanwhile, the total Cd content in soil also reduced by 11.64-46.75 and 21.41-54.11 % at jointing and filling stages, respectively. When the Cd concentration in soil was 20 mg kg(-1), the Cd extraction rate in shoots of Lu527-8 reached 2.12 and 2.85 % which increased 10.60 and 6.48 times compared with that of Lu527-4 at the jointing and filling stages, respectively. In conclusion, this study demonstrates that Lu527-8 shows great abilities of Cd accumulation and Cd removal potential from contaminated soils with different Cd treatments and it is a promising species for phytoextraction of Cd-contaminated soils.

  4. Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Segura, Sergi, E-mail: sergigarcia@ub.edu [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Keller, Jürg [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Brillas, Enric [Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Radjenovic, Jelena, E-mail: j.radjenovic@awmc.uq.edu.au [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia)

    2015-02-11

    Graphical abstract: - Highlights: • Mineralization of secondary effluent by anodic oxidation with BDD anode. • Complete removal of 29 pharmaceuticals and pesticides at trace level concentrations. • Organochlorine and organobromine byproducts were formed at low μM concentrations. • Chlorine species evolution assessed to evaluate the anodic oxidation applicability. - Abstract: Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl{sup −} ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl{sub 2}/HClO/ClO{sup −}), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO{sup −} species led to the production of ClO{sub 3}{sup −} and ClO{sub 4}{sup −} ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment.

  5. Simultaneous removal of chromium and arsenate from contaminated groundwater by ferrous sulfate: Batch uptake behavior

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Guan; Haoran Dong; Jun Ma; Irene M. C. Lo

    2011-01-01

    Chromium and/or arsenate removal by Fe(Ⅱ) as a function of pH, Fe(Ⅱ) dosage and initial Cr(Ⅵ)/As(Ⅴ) ratio were examined in batch tests.The presence of arsenate reduced the removal efficiency of chromium by Fe(Ⅱ), while the presence of chromate significantly increased the removal efficiency of arsenate by Fe(Ⅱ) at pH 6-8.In the absence of arsenate, chromium removal by Fe(Ⅱ) increased to a maximum with increasing pH from 4 to 7 and then decreased with a further increase in pH.The increment in Fe(Ⅱ) dosage resulted in an improvement in chromium removal and the improvement was more remarkable under alkaline conditions than that under acidic conditions.Chromium removal by Fe(Ⅱ) was reduced to a larger extent under neutral and alkaline conditions than that under acidic conditions due to the presence of 10 μmol/L arsenate.The presence of 20 μmol/L arsenate slightly improved chromium removal by Fe(Ⅱ) at pH 3.9-5.8, but had detrimental effects at pH 6.7-9.8.Arsenate removal was improved significantly at pH 4-9 due to the presence of 10 μmol/L chromate at Fe(Ⅱ) dosages of 20-60 μmol/L.Elevating the chromate concentration from 10 to 20 μmol/L resulted in a further improvement in arsenate removal at pH 4.0-4.6 when Fe(Ⅱ) was dosed at 30-60 μmol/L.

  6. Groundwater contamination with 2,6-dichlorobenzamide (BAM) and perspectives for its microbial removal

    DEFF Research Database (Denmark)

    Ellegaard-Jensen, Lea; Horemans, Benjamin; Raes, Bart

    2017-01-01

    degradation pathways, kinetics and degrader genes, and research has recently been presented on the application of strain Aminobacter sp. MSH1 for the purification of BAM-contaminated water. The aim of the present review was to provide insight into the issue of BAM contamination and to report on the current...... groundwater by deploying dedicated BAM-degrading bacteria in DWTP sand filters. Only a few bacterial strains with the capability to degrade BAM have been isolated, and of these, only three isolates belonging to the Aminobacter genus are able to mineralise BAM. Considerable effort has been made to elucidate...... status and knowledge with regard to the application of microorganisms for purification of BAM-contaminated water resources. This paper discusses the prospects and challenges for bioaugmentation of DWTP sand filters with specific BAM-degrading bacteria and identifies relevant perspectives for future...

  7. Effect of pulse current on energy consumption and removal of heavy metals during electrodialytic soil remediation

    DEFF Research Database (Denmark)

    Sun, Tian Ran

    Contamination of soils and groundwater keep attracting attention of worldwide. The contaminants of concern include a wide range of toxic pollutants such as heavy metals, radionuclides, and organic compounds. The environment and humans are exposed to these pollutants through different exposure...... pathways to unacceptable dosages, leading to intolerable adverse effects on both public health and the environment. In the last decades, soil and water remediation have gained growing awareness, as the necessity becomes clearer for development of such techniques for elimination of the negative impact from...... compartments. Therefore no current is wasted for carrying ions from one electrode compartment to the other. The EDR technique has been tested for decontamination of a variety of different heavy metal polluted particulate materials: mine tailings, soil, different types of fly ashes, sewage sludge, freshwater...

  8. EPA Removes Burrows Sanitation Site in Michigan from National List of Most Contaminated Sites

    Science.gov (United States)

    For Immediate Release No. 15-OPA142 CHICAGO - The U.S. Environmental Protection Agency today announced that the Burrows Sanitation Superfund site in Hartford Township, Van Buren County, Michigan, has been officially removed from the Agency's l

  9. Removal of chloramphenicol by macroporous adsorption resins in honey: a novel approach on reutilization of antibiotics contaminated honey.

    Science.gov (United States)

    Cheng, Ni; Gao, Hui; Deng, Jianjun; Wang, Bini; Xu, Ruihan; Cao, Wei

    2012-09-01

    The effects of different steps in honey production on chloramphenicol (CAP) levels and CAP removal from honey using macroporous adsorption resins (MARs) were investigated in this study. CAP residues in honey were quantified by enzyme-linked immunosorbent assay after each processing step including preheating, filtration, vacuum concentration and pasteurization. Vacuum concentration contributes the most reduction of CAP level (9.9%). Meanwhile, 5 types of MARs (including LSI-1, LSI-2, LSI-3, LS-803, and LS-903) were used in CAP adsorption. The results showed that LS-803 resin had higher adsorption rate of 86% than other resins in removing CAP from honey, and its optimal adsorption time and temperature were 40 min and 55 °C, respectively. The treated honey could be used as feed additive or biomass energy. Therefore, it would be a novel approach to reutilization of antibiotics contaminated honey.

  10. Long-pulsed Nd:YAG laser-assisted hair removal in Fitzpatrick skin types IV-VI.

    Science.gov (United States)

    Rao, Krishna; Sankar, Thangasamy K

    2011-09-01

    Unwanted hair is a common problem for which a variety of laser treatments is available. Laser treatment in dark-skinned individuals carries a higher risk of complications like hyperpigmentation and burn. The objective of this study was to evaluate efficacy and safety profile of laser-assisted hair removal in individuals with Fitzpatrick type IV-VI skin using long-pulsed Nd:YAG laser. Retrospective data was collected from 150 individuals with Fitzpatrick type IV-VI skin who underwent laser-assisted hair removal. This included area treated, fluence, number of treatments, and outcome. Data was also gathered on patient satisfaction and complications. The most common phototype was type IV (94%). The most frequently treated area was the face (84.7%) followed by the underarms and legs. Among the facial areas, the chin was the most frequently treated area followed by the upper lip and jaw line. The mean number of treatments was 8.9 (range 4-22). The maximum fluence averaged 26.8 Joules/cm(2) and was significantly higher for facial hair. Of the patients, 78.7% felt that their treatment was good or satisfactory. Mean hair reduction was 54.3%. Satisfaction from the treatment was significantly higher in individuals undergoing treatment of non-facial areas. Subsequent hair growth was slower and finer in 79.3% of the patients. There were no complications in 86% of the patients. All the complications were transient, with hyperpigmentation being the most frequent complication. Our results show that laser hair removal using the long-pulsed Nd:YAG laser is safe and effective in dark-skinned individuals with satisfactory results in most patients.

  11. Superfine powdered activated carbon (S-PAC) coatings on microfiltration membranes: Effects of milling time on contaminant removal and flux.

    Science.gov (United States)

    Amaral, Pauline; Partlan, Erin; Li, Mengfei; Lapolli, Flavio; Mefford, O Thompson; Karanfil, Tanju; Ladner, David A

    2016-09-01

    In microfiltration processes for drinking water treatment, one method of removing trace contaminants is to add powdered activated carbon (PAC). Recently, a version of PAC called superfine PAC (S-PAC) has been under development. S-PAC has a smaller particle size and thus faster adsorption kinetics than conventionally sized PAC. Membrane coating performance of various S-PAC samples was evaluated by measuring adsorption of atrazine, a model micropollutant. S-PACs were created in-house from PACs of three different materials: coal, wood, and coconut shell. Milling time was varied to produce S-PACs pulverized with different amounts of energy. These had different particles sizes, but other properties (e.g. oxygen content), also differed. In pure water the coal based S-PACs showed superior atrazine adsorption; all milled carbons had over 90% removal while the PAC had only 45% removal. With addition of calcium and/or NOM, removal rates decreased, but milled carbons still removed more atrazine than PAC. Oxygen content and specific external surface area (both of which increased with longer milling times) were the most significant predictors of atrazine removal. S-PAC coatings resulted in loss of filtration flux compared to an uncoated membrane and smaller particles caused more flux decline than larger particles; however, the data suggest that NOM fouling is still more of a concern than S-PAC fouling. The addition of calcium improved the flux, especially for the longer-milled carbons. Overall the data show that when milling S-PAC with different levels of energy there is a tradeoff: smaller particles adsorb contaminants better, but cause greater flux decline. Fortunately, an acceptable balance may be possible; for example, in these experiments the coal-based S-PAC after 30 min of milling achieved a fairly high atrazine removal (overall 80%) with a fairly low flux reduction (under 30%) even in the presence of NOM. This suggests that relatively short duration (low energy

  12. Removing Arsenic from Contaminated Drinking Water in Rural Bangladesh: Recent Fieldwork Results and Policy Implications

    Energy Technology Data Exchange (ETDEWEB)

    Mathieu, Johanna L.; Gadgil, Ashok J.; Kowolik, Kristin; Addy, Susan E.A.

    2009-09-17

    ARUBA (Arsenic Removal Using Bottom Ash) has proven effective at removing high concentrations of arsenic from drinking water in Bangladesh. During fieldwork in four sub-districts of the country, ARUBA reduced arsenic levels ranging from 200 to 900 ppb to below the Bangladesh standard of 50 ppb. The technology is cost-effective because the substrate--bottom ash from coal fired power plants--is a waste material readily available in South Asia. In comparison to similar technologies, ARUBA uses less media for arsenic removal due to its high surface area to volume ratio. Hence, less waste is produced. A number of experiments were conducted in Bangladesh to determine the effectiveness of various water treatment protocols. It was found that (1) ARUBA removes more than half of the arsenic from water within five minutes of treatment, (2) ARUBA, that has settled at the bottom of a treatment vessel, continues to remove arsenic for 2-3 days, (3) ARUBA's arsenic removal efficiency can be improved through sequential partial dosing (adding a given amount of ARUBA in fractions versus all at once), and (4) allowing water to first stand for two to three days followed by treatment with ARUBA produced final arsenic levels ten times lower than treating water directly out of the well. Our findings imply a number of tradeoffs between ARUBA's effective arsenic removal capacity, treatment system costs, and waste output. These tradeoffs, some a function of arsenic-related policies in Bangladesh (e.g., waste disposal regulations), must be considered when designing an arsenic removal system. We propose that the most attractive option is to use ARUBA in communityscale water treatment centers, installed as public-private partnerships, in Bangladeshi villages.

  13. Combining Solvent Extraction and Bioremediation for Removing Weathered Petroleum from Contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    WU Guo-Zhong; F.COULON; YANG Yue-Wei; LI Hong; SUI Hong

    2013-01-01

    This study aimed to evaluate the efficacy,practicality and sustainability of a combined approach based on solvent extraction and biodegradation to remediate the soils contaminated with high levels of weathered petroleum hydrocarbons.The soils used in this study were obtained from the Shengli Oilfield in China,which had a long history of contamination with high concentrations of petroleum hydrocarbons.The contaminated soils were washed using a composite organic solvent consisting of hexane and pentane (4:1,v/v) and then bioremediated in microcosms which were bioaugmentated with Bacillus subtilis FQ06 strains and/or rhamnolipid.The optimal solvent extraction conditions were determined as extraction for 20 min at 25 ℃ with solvent-soil ratio of 6:1 (v/w).On this basis,total petroleum hydrocarbon was decreased from 140000 to 14000 mg kg-1,which was further reduced to < 4000 mg kg-1 by subsequent bioremediation for 132 d.Sustainability assessment of this integrated technology showed its good performance for both short-and long-term effectiveness.Overall the results encouraged its application for remediating contaminated sites especially with high concentration weathered hydrocarbons.

  14. Removing external DNA contamination from arthropod predators destined for molecular gut-content analysis

    Science.gov (United States)

    Molecular gut-content analysis enables detection of arthropod predation with minimal disruption of ecosystem processes. Field and laboratory experiments have demonstrated that mass-collection methods, such as sweep-netting, vacuum sampling, and foliage beating, can lead to contamination of fed pred...

  15. Use of Continuous Magnetic Extraction for removal of feedstock contaminants in flow-through mode

    DEFF Research Database (Denmark)

    Paulus, Anja; Fischer, Ingo; Hobley, Timothy John;

    2014-01-01

    for binding large amounts of product. It can also be especially interesting if obtaining a high product yield is secondary to other considerations. For example if an excess of a low value waste stream is available, it may be acceptable that some target is lost to the adsorbent during contaminant binding...

  16. Influence of feed characteristics on the removal of micropollutants during the anaerobic digestion of contaminated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Barret, M., E-mail: barret@supagro.inra.fr [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, 11100 Narbonne (France); Barcia, G. Cea, E-mail: cea@supagro.inra.fr [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, 11100 Narbonne (France); Guillon, A., E-mail: a.guillon@ism.u-bordeaux1.fr [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, 11100 Narbonne (France); Carrere, H., E-mail: carrere@supagro.inra.fr [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, 11100 Narbonne (France); Patureau, D., E-mail: patureau@supagro.inra.fr [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, 11100 Narbonne (France)

    2010-09-15

    The removal of 13 polycyclic aromatic hydrocarbons, 7 polychlorobiphenyls and nonylphenol was measured during the continuous anaerobic digestion of five different sludge samples. The reactors were fed with one of the following: primary/secondary sludge (PS/SS), thermally treated PS, cellulose-added SS, or SS augmented with dissolved and colloidal matter (DCM). These various feeding conditions induced variable levels of micropollutant bioavailability (assumed to limit their biodegradation) and overall metabolism (supposed to be linked to micropollutant metabolism throughout co-metabolism). On the one hand, overall metabolism was higher with secondary sludge than with primary and the same was observed for micropollutant removal. However, when overall metabolism was enhanced thanks to cellulose addition, a negative influence on micropollutant removal was observed. This suggests that either the co-metabolic synergy would be linked to a specific metabolism or co-metabolism was not the limiting factor in this case. On the other hand, micropollutant bioavailability was presumably diminished by thermal treatment and increased by DCM addition. In both cases, micropollutant removal was reduced. These results suggest that neither overall metabolism nor bioavailability would absolutely limit micropollutant removal. Each phenomenon might alternatively predominate depending on the feed characteristics.

  17. Pharmaceuticals as emerging contaminants and their removal from water. A review.

    Science.gov (United States)

    Rivera-Utrilla, José; Sánchez-Polo, Manuel; Ferro-García, María Ángeles; Prados-Joya, Gonzalo; Ocampo-Pérez, Raúl

    2013-10-01

    The main objective of this study was to conduct an exhaustive review of the literature on the presence of pharmaceutical-derived compounds in water and on their removal. The most representative pharmaceutical families found in water were described and related water pollution issues were analyzed. The performances of different water treatment systems in the removal of pharmaceuticals were also summarized. The water treatment technologies were those based on conventional systems (chlorine, chlorine dioxide, wastewater treatment plants), adsorption/bioadsorption on activated carbon (from lotus stalks, olive-waste cake, coal, wood, plastic waste, cork powder waste, peach stones, coconut shell, rice husk), and advanced oxidation processes by means of ozonation (O₃, O₃/H₂O₂, O₃/activated carbon, O₃/biological treatment), photooxidation (UV, UV/H₂O₂, UV/K₂S₂O₈, UV/TiO₂, UV/H₂O₂/TiO₂, UV/TiO₂/activated carbon, photo-Fenton), radiolysis (e-Beam, ⁶⁰Co, ¹³⁷Cs. Additives used: H₂O₂, SO₃²⁻, HCO₃⁻, CH₃₋OH, CO₃²⁻, or NO₃⁻), and electrochemical processes (Electrooxidation without and with active chlorine generation). The effect of these treatments on pharmaceutical compounds and the advantages and disadvantages of different methodologies used were described. The most important parameters of the above water treatment systems (experimental conditions, removal yield, pharmaceutical compound mineralization, TOC removal, toxicity evolution) were indicated. The key publications on pharmaceutical removal from water were summarized.

  18. Linking Contaminant Mass Discharge to DNAPL Source Zone Architecture and Mass Removal

    Science.gov (United States)

    Pennell, K. D.; Suchomel, E. J.; Amos, B. K.; Loeffler, F. E.; Capiro, N. L.

    2007-05-01

    To evaluate the relationship between partial dense nonaqueous phase (DNAPL) mass removal and plume behavior, laboratory-scale experiments were conducted in a two-dimensional aquifer cell containing a tetrachloroethene (PCE) source zone and a down-gradient plume region. PCE-DNAPL saturation distributions were quantified using a light transmission system and expressed in terms of a ganglia-to-pool (GTP) volume ratio. To achieve incremental mass removal, the aquifer cells were flushed with a 4% Tween 80 surfactant solution that increased the solubility of PCE by more than two orders-of-magnitude with minimal mobilization of entrapped PCE-DNAPL. For a ganglia-dominated source zone (GTP = 1.6) greater than 70% mass removal was required before measurable reductions in mass discharge were realized, while for pool-dominated source zones (GTP < 0.3) reductions in mass discharge versus mass removal approached a 1:1 correlation. Current experiments are designed to evaluate the potential for coupling aggressive mass removal with microbial reductive dechlorination.

  19. Effect of activated NH3 on SO2 removal by pulse coronadischarge plasma in flue gas

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    NH3-activated electrode is placed in front of the electrode system of pulse corona discharge plasma. There are nozzles on the electrode. Positive DC high-voltage is applied on the nozzle-plate gap. NH3 is injected into the reactor through nozzles, at the same time, activated and treated. Tbese nozzles were proposed in order to make the additional gas pass through corona discharge regions near the tip of nozzles and increase the mount of radicals. The aim is to improve the De-SO2 efficiency by pulse discharge plasma in flue gas. The following topics are investigated and discussed in the paper: De-SO2 effect of single NH3-activated electrode, De-SO2 effect of activated NH3, the relationship between stoichiometric ratio of NH3 to SO2 and De-SO2 effect of activated NH3, mechanism of activated NH3 De-SO2 effect. The experimental result indicates that the De-SO2 efficiency can be increased 5 %-10 96 by activated NH3 on the original base of De-SO2 efficiency.

  20. Experimental demonstration of Martian soil simulant removal from a surface using a pulsed plasma jet.

    Science.gov (United States)

    Ticoş, C M; Scurtu, A; Toader, D; Banu, N

    2015-03-01

    A plasma jet produced in a small coaxial plasma gun operated at voltages up to 2 kV and working in pure carbon dioxide (CO2) at a few Torr is used to remove Martian soil simulant from a surface. A capacitor with 0.5 mF is charged up from a high voltage source and supplies the power to the coaxial electrodes. The muzzle of the coaxial plasma gun is placed at a few millimeters near the dusty surface and the jet is fired parallel with the surface. Removal of dust is imaged in real time with a high speed camera. Mars regolith simulant JSC-Mars-1A with particle sizes up to 5 mm is used on different types of surfaces made of aluminium, cotton fabric, polyethylene, cardboard, and phenolic.

  1. Experimental demonstration of Martian soil simulant removal from a surface using a pulsed plasma jet

    Science.gov (United States)

    Ticoş, C. M.; Scurtu, A.; Toader, D.; Banu, N.

    2015-03-01

    A plasma jet produced in a small coaxial plasma gun operated at voltages up to 2 kV and working in pure carbon dioxide (CO2) at a few Torr is used to remove Martian soil simulant from a surface. A capacitor with 0.5 mF is charged up from a high voltage source and supplies the power to the coaxial electrodes. The muzzle of the coaxial plasma gun is placed at a few millimeters near the dusty surface and the jet is fired parallel with the surface. Removal of dust is imaged in real time with a high speed camera. Mars regolith simulant JSC-Mars-1A with particle sizes up to 5 mm is used on different types of surfaces made of aluminium, cotton fabric, polyethylene, cardboard, and phenolic.

  2. The influences of iron characteristics, operating conditions and solution chemistry on contaminants removal by zero-valent iron: A review.

    Science.gov (United States)

    Sun, Yuankui; Li, Jinxiang; Huang, Tinglin; Guan, Xiaohong

    2016-09-01

    For successful application of a zero-valent iron (ZVI) system, of particular interest is the performance of ZVI under various conditions. The current review comprehensively summarizes the potential effects of the major influencing factors, such as iron intrinsic characteristics (e.g., surface area, iron impurities and oxide films), operating conditions (e.g., pH, dissolved oxygen, iron dosage, iron pretreatment, mixing conditions and temperature) and solution chemistry (e.g., anions, cations and natural organic matter) on the performance of ZVI reported in literature. It was demonstrated that all of the factors could exert significant effects on the ZVI performance toward contaminants removal, negatively or positively. Depending on the removal mechanisms of the respective contaminants and other environmental conditions, an individual variable may exhibit different effects. On the other hand, many of these influences have not been well understood or cannot be individually isolated in experimental or natural systems. Thus, more research is required in order to elucidate the exact roles and mechanisms of each factor in affecting the performance of ZVI. Furthermore, based on these understandings, future research may attempt to establish some feasible strategies to minimize the deteriorating effects and utilize the positive effects so as to improve the performance of ZVI.

  3. Potential for heavy metal (copper and zinc) removal from contaminated marine sediments using microalgae and light emitting diodes

    Science.gov (United States)

    Kwon, Hyeong Kyu; Jeon, Jin Young; Oh, Seok Jin

    2017-03-01

    The effects of monochromatic (blue, yellow and red LED) and mixed wavelengths (fluorescent lamp) on the adsorption and absorption of Cu and Zn by Phaeodactylum tricornutum, Nitzschia sp., Skeletonema sp., and Chlorella vulgaris were investigated. In addition, we confirmed the potential of microalgae for phytoremediation of these heavy metals from contaminated marine sediment by using microcosm experiments that incorporated LEDs and semipermeable membrane (SPM) tube containing microalgae. Among the four microalgae, C. vulgaris grown under red LED exhibited the highest Cu and Zn removal with values of 17.5 × 10-15 g Cu/cell and 38.3 × 10-15 g Zn/cell, respectively. Thus, C. vulgaris could be a useful species for phytoremediation. In the microcosm experiments with SPM containing C. vulgaris, the highest Cu and Zn removal from sediment and interstitial water showed under red LED. Therefore, phytoremediation using LED and SPM tube containing microalgae could be utilized as an eco-friendly technique for remediating contaminated marine sediment.

  4. Potential for heavy metal (copper and zinc) removal from contaminated marine sediments using microalgae and light emitting diodes

    Science.gov (United States)

    Kwon, Hyeong Kyu; Jeon, Jin Young; Oh, Seok Jin

    2017-01-01

    The effects of monochromatic (blue, yellow and red LED) and mixed wavelengths (fluorescent lamp) on the adsorption and absorption of Cu and Zn by Phaeodactylum tricornutum, Nitzschia sp., Skeletonema sp., and Chlorella vulgaris were investigated. In addition, we confirmed the potential of microalgae for phytoremediation of these heavy metals from contaminated marine sediment by using microcosm experiments that incorporated LEDs and semipermeable membrane (SPM) tube containing microalgae. Among the four microalgae, C. vulgaris grown under red LED exhibited the highest Cu and Zn removal with values of 17.5 × 10-15 g Cu/cell and 38.3 × 10-15 g Zn/cell, respectively. Thus, C. vulgaris could be a useful species for phytoremediation. In the microcosm experiments with SPM containing C. vulgaris, the highest Cu and Zn removal from sediment and interstitial water showed under red LED. Therefore, phytoremediation using LED and SPM tube containing microalgae could be utilized as an eco-friendly technique for remediating contaminated marine sediment.

  5. The potential role of biochar in the removal of organic and microbial contaminants from potable and reuse water: A review.

    Science.gov (United States)

    Inyang, Mandu; Dickenson, Eric

    2015-09-01

    In this work, the potential benefits, economics, and challenges of applying biochar in water treatment operations to remove organic and microbial contaminants was reviewed. Minimizing the use of relatively more expensive traditional sorbents in water treatment is a motivating aspect of biochar production, e.g., $246/ton non-activated biochar to $1500/ton activated carbon. Biochar can remove organic contaminants in water, such as some pesticides (0.02-23 mg g(-1)), pharmaceutical and personal care products (0.001-59 mg g(-1)), dyes (2-104 mg g(-1)), humic acid (60 mg g(-1)), perfluorooctane sulfonate (164 mg g(-1)), and N-nitrosomodimethylamine (3 mg g(-1)). Including adsorption/filtration applications, biochar can potentially be used to inactivate Escherichia coli via disinfection, and transform 95% of 2-chlorobiphenyl via advanced oxidation processes. However, more sorption data using biochar especially at demonstration-scale, for treating potable and reuse water in adsorption/filtration applications will help establish the potential of biochars to serve as surrogates for activated carbons.

  6. Conditions for effective removal of pyrene from an artificially contaminated soil using Pseudomonas aeruginosa 57SJ rhamnolipids

    Energy Technology Data Exchange (ETDEWEB)

    Bordas, Francois [Institut national de la recherche scientifique, Centre INRS-Eau-Terre-Environnement, Universite du Quebec, 2800 rue Einstein, C.P. 7500, Sainte-Foy, Quebec, G1V 4C7 (Canada)]. E-mail: francois.bordas@unilim.fr; Lafrance, Pierre [Institut national de la recherche scientifique, Centre Eau, Terre et Environnement, Universite du Quebec, 490, rue de la Couronne, Quebec, G1K 9A9 (Canada)]. E-mail: pierre_lafrance@inrs-ete.uquebec.ca; Villemur, Richard [Institut national de la recherche scientifique, Centre INRS-Institut Armand Frappier, Universite du Quebec, 531 bd des Prairies, Laval, Quebec, H7V 1B7 (Canada)]. E-mail: richard.villemur@inrs-iaf.uquebec.ca

    2005-11-15

    The efficacy of a new rhamnolipid biosurfactants mixture to enhance the removal of pyrene from a soil artificially contaminated was investigated. The molar solubilization ratio (MSR) and the partition coefficient between the micelles and water (log K {sub m}) were found to be 7.5 x 10{sup -3} and 5.7, respectively. From soil column studies, the pyrene removal increased linearly with the concentration of the injected biosurfactants solution above the effective critical micellar concentration (0.4 g L{sup -1}). Flushing with a 5.0 g L{sup -1} biosurfactants solution increased the pyrene concentration in the effluent by 178 times. At high biosurfactants' concentrations (2.5 and 5.0 g L{sup -1}), the cumulative pyrene recovery reached 70%. This pyrene remobilization takes place independently of the soil organic carbon solubilization. This study provides a combination of batch and column experiments in order to find the conditions for effective soil remediation using a new rhamnolipids mixture. - The potential of newly isolated biosurfactants to mobilize PAHs from contaminated soils was evaluated from the determination in dynamic conditions of their effective critical micellar concentration.

  7. Removal of an acid fume system contaminated with perchlorates located within hot cell

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, K.E.; Henslee, S.P.; Vroman, W.R.; Krsul, J.R.; Michelbacher, J.A.; Knighton, G.C.

    1992-09-01

    An add scrubbing system located within the confines of a highly radioactive hot cell at Argonne National Laboratory-West (ANL-W) was remotely removed. The acid scrubbing system was routinely used for the dissolution of irradiated reactor fuel samples and structural materials. Perchloric acid was one of the acids used in the dissolution process and remained in the system with its inherent risks. Personnel could not enter the hot cell to perform the dismantling of the acid scabbing system due to the high radiation field and the explosion potential associated with the perchlorates. A robot was designed and built at ANL-W and used to dismantle the system without the need for personnel entry into the hot cell. The robot was also used for size reduction of removed components and loading of the removed components into waste containers.

  8. Removal of arsenic from contaminated groundwater with application of iron electrodissolution, aeration and sand filtration

    DEFF Research Database (Denmark)

    Kowalski, Krysztof; Arturi, Kasia; Søgaard, Erik Gydesen

    2014-01-01

    The results from a new water treatment system for arsenic removal are presented. The technology is based on the employment of an electrolytic iron dissolution and efficient aeration procedure prior to sand filtration. The treatment was introduced and investigated in a pilot scale plant and full...... scale waterworks. The pilot scale results showed a possibility for an efficient arsenic removal from spiked solutions (with As in the range of 50–85 μg/L) depending on the process conditions (flow and applied current). In the waterworks where the system was implemented for a period of 14 months...

  9. Evaluation of the effect of three disinfectants on removing HBV contamination

    Directory of Open Access Journals (Sweden)

    Arami S

    2006-06-01

    Full Text Available Background and Aim: Infection control is an important issue in dentistry. Without an efficient infection control, pathogens left on instruments and working surfaces will have potential danger to patients’ health. In this research, antiviral effect of three disinfectants: 0.5% sodium hypochlorite 0.05% sodium hypochlorite and Deconex 50 AF, on HBV was investigated. Materials and Methods: In this interventional (before-after study; serums of 26 HBV positive patients were analyzed by PCR HBV analysis and 9 contaminated species were obtained to test three disinfectants. 36 agar plates were prepared with the contaminated serums. 27 of the plates were disinfected in 3 separate groups with the above mentioned solutions. Nine remaining plates were not disinfected (control. Swabs wetted by BSAS (Bovine Serum Albumin Sodium Chloride medium were applied on the surface of the plates and the were kept in the transferred medium and sent to virology-lab of Pasteur Institute. HBV DNA were detected by commercial kit of HBV PCR (polymerase chain reaction method. Data were analyzed by Cochrane test with p<0.05 as the limit of significance. Results: None of samples disinfected with 0.5% sodium hypochlorite showed contamination. 11/1% of samples disinfected with 0.05% sodium hypochlorite and 44/4% of samples disinfected with Deconex 50 AF remained contaminated. Statistical analysis showed a significant difference between 0.5% sodium hypochlorite and the other groups. Conclusion: Our findings revealed that 0.5% sodium hypochlorite solution is a strong and efficient disinfectant against HBV. Key Words: HBV; Sodium hypochlorite

  10. Assessment of Self-Contamination During Removal of Personal Protective Equipment for Ebola Patient Care.

    Science.gov (United States)

    Casanova, Lisa M; Teal, Lisa J; Sickbert-Bennett, Emily E; Anderson, Deverick J; Sexton, Daniel J; Rutala, William A; Weber, David J

    2016-10-01

    OBJECTIVE Ebola virus disease (EVD) places healthcare personnel (HCP) at high risk for infection during patient care, and personal protective equipment (PPE) is critical. Protocols for EVD PPE doffing have not been validated for prevention of viral self-contamination. Using surrogate viruses (non-enveloped MS2 and enveloped Φ6), we assessed self-contamination of skin and clothes when trained HCP doffed EVD PPE using a standardized protocol. METHODS A total of 15 HCP donned EVD PPE for this study. Virus was applied to PPE, and a trained monitor guided them through the doffing protocol. Of the 15 participants, 10 used alcohol-based hand rub (ABHR) for glove and hand hygiene and 5 used hypochlorite for glove hygiene and ABHR for hand hygiene. Inner gloves, hands, face, and scrubs were sampled after doffing. RESULTS After doffing, MS2 virus was detected on the inner glove worn on the dominant hand for 8 of 15 participants, on the non-dominant inner glove for 6 of 15 participants, and on scrubs for 2 of 15 participants. All MS2 on inner gloves was observed when ABHR was used for glove hygiene; none was observed when hypochlorite was used. When using hypochlorite for glove hygiene, 1 participant had MS2 on hands, and 1 had MS2 on scrubs. CONCLUSIONS A structured doffing protocol using a trained monitor and ABHR protects against enveloped virus self-contamination. Non-enveloped virus (MS2) contamination was detected on inner gloves, possibly due to higher resistance to ABHR. Doffing protocols protective against all viruses need to incorporate highly effective glove and hand hygiene agents. Infect Control Hosp Epidemiol 2016;1-6.

  11. Dynamics of PCB removal and detoxification in historically contaminated soils amended with activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyeva, Galina K., E-mail: gkvasilyeva@issp.psn.r [Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino 142290 (Russian Federation); Strijakova, Elena R. [Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino 142290 (Russian Federation); Nikolaeva, Svetlana N.; Lebedev, Albert T. [Chemistry Department of Moscow State University, Moscow (Russian Federation); Shea, Patrick J. [School of Natural Resources, University of Nebraska-Lincoln (United States); Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Lincoln, NE 68583-0817 (United States)

    2010-03-15

    Activated carbon (AC) can help overcome toxicity of pollutants to microbes and facilitate soil bioremediation. We used this approach to treat a Histosol and an Alluvial soil historically contaminated with PCB (4190 and 1585 mg kg{sup -1}, respectively; primarily tri-, tetra- and pentachlorinated congeners). Results confirmed PCB persistence; reductions in PCB extractable from control and AC-amended soils were mostly due to a decrease in tri- and to some extent tetrachlorinated congeners as well as formation of a bound fraction. Mechanisms of PCB binding by soil and AC were different. In addition to microbial degradation of less chlorinated congeners, we postulate AC catalyzed dechlorination of higher chlorinated congeners. A large decrease in bioavailable PCB in AC-amended soils was demonstrated by greater clover germination and biomass. Phytotoxicity was low in treated soils but remained high in untreated soils for the duration of a 39-month experiment. These observations indicate the utility of AC for remediation of soils historically contaminated with PCB. - Activated carbon promotes remediation of soils historically contaminated with PCB.

  12. Emerging organic contaminant removal depending on primary treatment and operational strategy in horizontal subsurface flow constructed wetlands: influence of redox.

    Science.gov (United States)

    Avila, Cristina; Reyes, Carolina; Bayona, Josep María; García, Joan

    2013-01-01

    This study aimed at assessing the influence of primary treatment (hydrolytic upflow sludge blanket (HUSB) reactor vs. conventional settling) and operational strategy (alternation of saturated/unsaturated phases vs. permanently saturated) on the removal of various emerging organic contaminants (i.e. ibuprofen, diclofenac, acetaminophen, tonalide, oxybenzone, bisphenol A) in horizontal subsurface flow constructed wetlands. For that purpose, a continuous injection experiment was carried out in an experimental treatment plant for 26 days. The plant had 3 treatment lines: a control line (settler-wetland permanently saturated), a batch line (settler-wetland operated with saturate/unsaturated phases) and an anaerobic line (HUSB reactor-wetland permanently saturated). In each line, wetlands had a surface area of 2.95 m(2), a water depth of 25 cm and a granular medium D(60) = 7.3 mm, and were planted with common reed. During the study period the wetlands were operated at a hydraulic and organic load of 25 mm/d and about 4.7 g BOD/m(2)d, respectively. The injection experiment delivered very robust results that show how the occurrence of higher redox potentials within the wetland bed promotes the elimination of conventional quality parameters as well as emerging microcontaminants. Overall, removal efficiencies were always greater for the batch line than for the control and anaerobic lines, and to this respect statistically significantly differences were found for ibuprofen, diclofenac, oxybenzone and bisphenol A. As an example, ibuprofen, whose major removal mechanism has been reported to be biodegradation under aerobic conditions, showed a higher removal in the batch line (85%) than in the control (63%) and anaerobic (52%) lines. Bisphenol A showed also a great dependence on the redox status of the wetlands, finding an 89% removal rate for the batch line, as opposed to the control and anaerobic lines (79 and 65%, respectively). Furthermore, diclofenac showed a greater

  13. Heavy metals removal from contaminated sewage sludge by naturally fermented raw liquid from pineapple wastes.

    Science.gov (United States)

    Dacera, Dominica Del Mundo; Babel, Sandhya

    2007-01-01

    The large amount of unutilised pineapple wastes produced every year in tropical countries, particularly in Thailand, adds to the existing environmental pollution problems of the country. This study investigated the utilisation of pineapple wastes to treat another form of waste (sludge) from wastewater treatment facilities in Thailand. Laboratory scale studies were carried out to determine the potential of using naturally fermented raw liquid from pineapple wastes as a source of citric acid in the extraction of Cr, Cu, Pb, Ni and Zn from anaerobically digested sewage sludge. Results of the leaching study revealed its effectiveness in extracting Zn (at 92%) at pH 3.67 and a short leaching time of only 2 h, and Ni at almost 60% removal at the same leaching time. Chromium removal was also high at almost 75% at a longer leaching time of 11 days. Variation in metal removal efficiencies may also be attributed to the forms of metals in sludge, with metals predominantly in the exchangeable and oxidisable phases showing ease of leachability (such as Zn). Compared to citric acid, at pH approaching 4.0, naturally fermented raw liquid seemed to be more effective in the removal of Zn and Cu at the same leaching time of 2 h, and Cr at a longer leaching time of 11 days. The pineapple pulp, which is a by-product of the process, can still be used as animal feed because of its high protein content.

  14. The effect of nutrient supplementation on the biofiltration removal of butanal in contaminated air

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Vriens, L.; Verachtert, H.

    1993-01-01

    Butanal is one of the odorous compounds produced in the animal-rendering and food-processing industries and also in sewage-treatment plants. It shows the necessity for complementing such plants with systems for off-gas treatment. Biofiltration using simple packing material was tested for the removal

  15. Removal of Copper and Iron Contamination from Chromic Acid Electroplating Baths Using Electrodialysis with Caustic Catholyte

    Science.gov (United States)

    1991-06-01

    and other membrane processes have been applied to wastewater treatment. Some of these industrial applications for electrodialysis have been the...removal of salts from cheese whey , treatment of boiler feed waters, acid recovery in steel processing, and phosphoric acid concentration (19,20,22). In

  16. Assessing Changes in Contaminant Fluxes Following Dam Removal in an Urbanized River

    Science.gov (United States)

    Restoration of rivers and their associated ecosystems is a growing priority for government agencies (e.g., NOAA, USEPA), as well as conservation organizations. Dam removal is a major component of many restoration projects credited with reintroducing fish species, improving water...

  17. Monitoring Changes in Contaminant Fluxes Resulting from Dam Removal in an Urbanized River.

    Science.gov (United States)

    Restoration of rivers and their associated ecosystems is a growing priority for government agencies (e.g., NOAA, USEPA), as well as conservation organizations. Dam removal is a major component of many restoration projects credited with reintroducing fish species, improving water...

  18. Monitoring Organic Contaminant Fluxes Following Dam Removal Utilizing Passive Sampler Technology

    Science.gov (United States)

    Restoration of riverine habitats and their associated ecosystems is a growing priority for government agencies (e.g., USEPA, NOAA, USDA), as well as non-profit conservation organizations (e.g., American Rivers). Dam removal is a major component of many restoration projects credi...

  19. Microbial contamination of removable dental prosthesis at different interval of usage: An in vitro study

    National Research Council Canada - National Science Library

    Nair, VijitaVijay; Karibasappa, GN; Dodamani, Arun; Prashanth, VK

    2016-01-01

    ... the quality of life. Though development of implant prosthesis has increased recently, the demand for partial and full dentures is still very high. For those who cannot afford fixed dentures due to very small amount of teeth left, as well as for financial reasons, a removable dental prosthesis remains the only viable solution.[3],[4] Complete den...

  20. Enhancement of Methane Concentration by Removing Contaminants from Biogas Mixtures Using Combined Method of Absorption and Adsorption

    Directory of Open Access Journals (Sweden)

    Muhammad Rashed Al Mamun

    2017-01-01

    Full Text Available We report a laboratory scale combined absorption and adsorption chemical process to remove contaminants from anaerobically produced biogas using cafeteria (food, vegetable, fruit, and cattle manure wastes. Iron oxide (Fe2O3, zero valent iron (Feo, and iron chloride (FeCl2 react with hydrogen sulfide (H2S to deposit colloidal sulfur. Silica gel, sodium sulfate (Na2SO4, and calcium oxide (CaO reduce the water vapour (H2O and carbon dioxide (CO2. It is possible to upgrade methane (CH4 above 95% in biogas using chemical or physical absorption or adsorption process. The removal efficiency of CO2, H2S, and H2O depends on the mass of removing agent and system pH. The results showed that Ca(OH2 solutions are capable of reducing CO2 below 6%. The H2S concentration was reduced to 89%, 90%, 86%, 85%, and 96% for treating with 10 g of FeCl2, Feo (with pH, Fe2O3, Feo, and activated carbon, respectively. The H2O concentration was reduced to 0.2%, 0.7%, 0.2%, 0.2%, and 0.3% for treating raw biogas with 10 g of silica gel and Na2SO4 for runs R1, R2, R3, R4, and R5, respectively. Thus, given the successful contaminant elimination, the combined absorption and adsorption process is a feasible system for biogas purification.

  1. Biological Removal of Ammonia from Contaminated Air Streams Using Biofiltration System

    Directory of Open Access Journals (Sweden)

    MR Shahmansouri, H Taghipour, B Bina, H Movahdian

    2005-04-01

    Full Text Available Ammonia is a colorless, toxic, reactive and corrosive gas with a sharp odor. It is irritating to the skin, eyes, nose, throat, and lungs. Ammonia gas occurs in the environment naturally and is emitted by many industries and, therefore, its control is essential. Biofiltration is a new emerging technology that is being used as a control procedure. This study evaluates the use of a mixture of compost, sludge, and pieces of PVC as biofilter media to remove ammonia gas. The study investigates the effects of parameters such as inlet concentration, accumulation time, and depth of filter media to evaluate the removal efficiency. A laboratory scale biofilter column was built and operated to investigate the removal of ammonia from a waste gas stream. The findings indicate that for inlet concentrations of 236 ppm, and ammonia loading of less than 9.86 g-NH3/m3.h at empty bed residence time of 1 min, an ammonia removal efficiency of more than 99.9% was obtained. The acclimation period of the bacteria was 10 days. The average pressure drop during measurement was 4.44 mm H2O. The study also revealed that for concentration levels of 99, 211, and 236 ppmv, biofilter media depths of 40, 80, and 120 cm will be required, respectively. The results obtained in this study indicate that the biofiltration system composed of compost in the mixture of sludge and smashed polyvinyl chloride as biofilter media is an efficient method for the removal of ammonia from waste gas streams. It is also found that the optimum depth of biofilter media depends on the inlet concentration of ammonia.

  2. Sequential ozone advanced oxidation and biological oxidation processes to remove selected pharmaceutical contaminants from an urban wastewater.

    Science.gov (United States)

    Espejo, Azahara; Aguinaco, Almudena; García-Araya, J F; Beltrán, Fernando J

    2014-01-01

    Sequential treatments consisting in a chemical process followed by a conventional biological treatment, have been applied to remove mixtures of nine contaminants of pharmaceutical type spiked in a primary sedimentation effluent of a municipal wastewater. Combinations of ozone, UVA black light (BL) and Fe(III) or Fe₃O₄ catalysts constituted the chemical systems. Regardless of the Advanced Oxidation Process (AOP), the removal of pharmaceutical compounds was achieved in 1 h of reaction, while total organic carbon (TOC) only diminished between 3.4 and 6%. Among selected ozonation systems to be implemented before the biological treatment, the application of ozone alone in the pre-treatment stage is recommended due to the increase of the biodegradability observed. The application of ozone followed by the conventional biological treatment leads high TOC and COD removal rates, 60 and 61%, respectively, and allows the subsequent biological treatment works with shorter hydraulic residence time (HRT). Moreover, the influence of the application of AOPs before and after a conventional biological process was compared, concluding that the decision to take depends on the characterization of the initial wastewater with pharmaceutical compounds.

  3. Laccase-syringaldehyde-mediated degradation of trace organic contaminants in an enzymatic membrane reactor: Removal efficiency and effluent toxicity.

    Science.gov (United States)

    Nguyen, Luong N; van de Merwe, Jason P; Hai, Faisal I; Leusch, Frederic D L; Kang, Jinguo; Price, William E; Roddick, Felicity; Magram, Saleh F; Nghiem, Long D

    2016-01-01

    Redox-mediators such as syringaldehyde (SA) can improve laccase-catalyzed degradation of trace organic contaminants (TrOCs) but may increase effluent toxicity. The degradation performance of 14 phenolic and 17 non-phenolic TrOCs by a continuous flow enzymatic membrane reactor (EMR) at different TrOC and SA loadings was assessed. A specific emphasis was placed on the investigation of the toxicity of the enzyme (laccase), SA, TrOCs and the treated effluent. Batch tests demonstrated significant individual and interactive toxicity of the laccase and SA preparations. Reduced removal of resistant TrOCs by the EMR was observed for dosages over 50μg/L. SA addition at a concentration of 10μM significantly improved TrOC removal, but no removal improvement was observed at the elevated SA concentrations of 50 and 100μM. The treated effluent showed significant toxicity at SA concentrations beyond 10μM, providing further evidence that higher dosage of SA must be avoided. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Removal of PCBs in contaminated soils by means of chemical reduction and advanced oxidation processes.

    Science.gov (United States)

    Rybnikova, V; Usman, M; Hanna, K

    2016-09-01

    Although the chemical reduction and advanced oxidation processes have been widely used individually, very few studies have assessed the combined reduction/oxidation approach for soil remediation. In the present study, experiments were performed in spiked sand and historically contaminated soil by using four synthetic nanoparticles (Fe(0), Fe/Ni, Fe3O4, Fe3 - x Ni x O4). These nanoparticles were tested firstly for reductive transformation of polychlorinated biphenyls (PCBs) and then employed as catalysts to promote chemical oxidation reactions (H2O2 or persulfate). Obtained results indicated that bimetallic nanoparticles Fe/Ni showed the highest efficiency in reduction of PCB28 and PCB118 in spiked sand (97 and 79 %, respectively), whereas magnetite (Fe3O4) exhibited a high catalytic stability during the combined reduction/oxidation approach. In chemical oxidation, persulfate showed higher PCB degradation extent than hydrogen peroxide. As expected, the degradation efficiency was found to be limited in historically contaminated soil, where only Fe(0) and Fe/Ni particles exhibited reductive capability towards PCBs (13 and 18 %). In oxidation step, the highest degradation extents were obtained in presence of Fe(0) and Fe/Ni (18-19 %). The increase in particle and oxidant doses improved the efficiency of treatment, but overall degradation extents did not exceed 30 %, suggesting that only a small part of PCBs in soil was available for reaction with catalyst and/or oxidant. The use of organic solvent or cyclodextrin to improve the PCB availability in soil did not enhance degradation efficiency, underscoring the strong impact of soil matrix. Moreover, a better PCB degradation was observed in sand spiked with extractable organic matter separated from contaminated soil. In contrast to fractions with higher particle size (250-500 and oxidation reactions in soils and understand the impact of soil properties on remediation performance.

  5. Growth of carbon structures on chrysotile surface for organic contaminants removal from wastewater.

    Science.gov (United States)

    Lemos, Bruno R S; Soares, Érico A R; Teixeira, Ana Paula C; Ardisson, José D; Fernandez-Outon, Luis E; Amorim, Camila C; Lago, Rochel M; Moura, Flávia C C

    2016-09-01

    Amphiphilic magnetic composites were produced based on chrysotile mineral and carbon structures by chemical vapor deposition at different temperatures (600-900 °C) and cobalt as catalyst. The materials were characterized by elemental analysis, X-ray diffraction, vibrating sample magnetometry, adsorption and desorption of N2, Raman spectroscopy, scanning electronic microscopy, and thermal analysis showed an effective growth of carbon structures in all temperatures. It was observed that at 800 and 900 °C, a large amount of carbon structures are formed with fewer defects than at 600 and 700 °C, what contributes to their stability. In addition, the materials present magnetic phases that are important for their application as catalysts and adsorbents. The materials have shown to be very active to remove the oil dispersed in a real sample of emulsified wastewater from biodiesel production and to remove methylene blue by adsorption and oxidation via heterogeneous Fenton mechanism.

  6. Ammonia removal from wastewater by ion exchange in the presence of organic contaminants.

    Science.gov (United States)

    Jorgensen, T C; Weatherley, L R

    2003-04-01

    The scope of this study was the removal of ammonium by ion exchange from simulated wastewater. The study looks at the effect of organics upon ammonium ion exchange equilibrium uptake. The ion exchangers included a natural zeolite clinoptilolite, and two polymeric exchangers, Dowex 50w-x8, and Purolite MN500. The organic compounds studied included citric acid and a number of proteins. The traditional method for removal of ammonium and organic pollutants from wastewater is biological treatment, but ion exchange offers a number of advantages including the ability to handle shock loadings and the ability to operate over a wider range of temperatures. The results show that in most of the cases studied, the presence of organic compounds enhances the uptake of ammonium ion onto the ion exchangers.

  7. Effect of surfactant on removal of particle contamination on Si wafers in ULSI

    Institute of Scientific and Technical Information of China (English)

    TAN Bai-mei; LI Wei-wei; NIU Xin-huan; WANG Sheng-li; LIU Yu-ling

    2006-01-01

    The adsorption mechanism of particle on the surface of silicon wafer after polishing or grinding whose surface force field is very strong was discussed,and the removal method of particle was studied. Particle is deposited on the wafer surface by interactions,mainly including the Van der Waals forces and static forces. In order to suppress particles depositing on the wafer surface,it is essential that the wafer surface and the particles should have the same polarity of the zeta potential. According to colloid chemistry and lots of experiments,this can be achieved by adding surfactants. Nonionic complex surfactant was used as megasonic cleaning solution,and the adsorptive state of particle on Si wafers was effectively controlled. The efficiency and effect of megasonic particle removal is greatly improved. A perfect result is also obtained in wafer cleaning.

  8. Subsurface flow wetlands for the removal of arsenic and metals from contaminated water

    OpenAIRE

    Lizama Allende, Katherine

    2017-01-01

    The presence of arsenic (As) in aquatic environments is a worldwide concern due to its toxicity and chronic effects. In many cases, the choice of treatment technologies is limited due to the isolated location of the water source and the high cost of conventional treatment technologies. In addition, other pollutants are often found alongside As, such as iron (Fe) and boron (B). Constructed wetlands have shown capability to remove As and metals. However, few experimental studies have been under...

  9. Removal of nutrients by algae from municipal wastewater contaminated with heavy metals

    OpenAIRE

    Aryal, Bigyan

    2015-01-01

    Selected species of algae (green algae and blue green algae) were cultivated in municipal wastewater using PBR (photo-bioreactor) bottles. Uptake of nutrients by these algae species was measured on different dates. From the results of the experiments, it was observed that a combination of certain blue green algae species (cyanobacteria) was able to remove most of the nutrients from the wastewater. The presence of heavy metal ions in the wastewater also affected the nutrient-absorbing capacit...

  10. Atomic Oxygen Cleaning Shown to Remove Organic Contaminants at Atmospheric Pressure

    Science.gov (United States)

    Rutledge, Sharon K.

    1998-01-01

    The NASA Lewis Research Center has developed and filed for a patent on a method to produce atomic oxygen at atmospheric pressure by using a direct current arc in a gas flow mixture of oxygen and helium. A prototype device has been tested for its ability to remove various soot residues from surfaces exposed to fire, and various varnishes such as acrylic and egg white.

  11. Copper, lead and zinc removal from metal-contaminated wastewater by adsorption onto agricultural wastes.

    Science.gov (United States)

    Janyasuthiwong, Suthee; Phiri, Sheila M; Kijjanapanich, Pimluck; Rene, Eldon R; Esposito, Giovanni; Lens, Piet N L

    2015-01-01

    The use of agricultural wastes (groundnut shell, orange and banana peel, rice husk, coconut husk and Wawa tree saw dust) as potential cost-effective adsorbent for heavy metal removal from wastewater was evaluated. The effect of pH (2.0-6.0), adsorbent dosage (0.6-2.2 g), contact time (10-130 min) and initial concentration (Pb: 5-105 mg/L, Cu and Zn: 2.5-52.7 mg/L) on the metal removal efficiency and uptake capacity were investigated using response surface methodology to optimize the process conditions. Groundnut shell showed a high potential to remove Cu, Pb and Zn from synthetic wastewater. The highest removal efficiencies with groundnut as the adsorbent were 85% at pH 5.0 for Cu and 98% at pH 3.0 for Pb and Zn. The optimum conditions obtained were 2.5 g adsorbent with 40.7 mg/L Cu at pH 4.4 and 64 min contact time, 2.5 g adsorbent with 196.1 mg/L Pb at pH 5.6 and 60 min contact time and 3.1 g adsorbent with 70.2 mg/L Zn at pH 4.3 and 50 min contact time, for Cu, Pb and Zn, respectively. The regeneration of the groundnut shell was possible for a maximum of three cycles using 0.2 M HCl as the desorbing solution without any significant change in the adsorbing efficiency.

  12. Efficiency of Tea Disposal from Cafeteria for Removal Nickel ion from Contaminated Groundwater

    Directory of Open Access Journals (Sweden)

    Rusul Nasser Mohammed

    2017-07-01

    Full Text Available This work aims to study the removal of Nickel from ground water using low cost adsorbent tea waste from cafeteria. The total adsorbed amounts, equilibrium uptakes and overall removal efficiency of Nickel were determined by investigating the breakthrough curve obtained at different inlet Nickel concentrations, various pH value, gain size of waste tea and bed height. Decrease in the grain size of adsorbent tea from 0.3 to 0.05 cm resulted in essential increase in the removal rate and total adsorbed amounts while increasing the bed depth leads the increase of bed capability and the breakthrough period. The experimental data were calibrated using three isotherm models, Dubinin- Radushkevich (DRM Langmuir (LM , Freundlich (FM where the experimental data is well fitted to the Langmuir (LM. Experimental and theoretical breakthrough study showed that the prolonged breakthrough period and maximum capability of nickel is achieved at pH of 3, 125 mg/L of inlet concentration and 0.5 m of bed depth. As a final engineering observation, waste tea from cafeteria is a good and low-cost material that can absorb nickel from groundwater.

  13. Selective removal of Cu(Ⅱ) from contaminated water using molecularly imprinted polymer

    Institute of Scientific and Technical Information of China (English)

    Jingyao QI; Xin LI; Ying LI; Jianhua ZHU; Liangsheng QIANG

    2008-01-01

    A synthetic molecularly imprinted polymer (MIP) was prepared by noncovalent imprinting technique for the selective removal of Cu2+ from aqueous solutions. In the preparation of imprinted polymer, Cu2+ was used as the template, oleic acid as the functional monomer and divinylbenzene as the cross-linker. The surface morphol-ogies and characteristics of the MIP were determined by BET, scanning electron microscopy (SEM), FTIR and energy dispersive X-ray spectrometer (EDS). The proper adsorption and selective recognition ability of the MIP were studied by an equilibrium-adsorption method. In general, the removal efficiency of Cu2+ increased rapidly with pH from 2 to 7 and decreased at a pH 8. The removal efficiency of Cu2+ increased with temperature from 25℃ to 50℃. Competitive adsorption studies showed that the coexisting cations have no obvious influence on the adsorption of Cu2+. In addition, the variation in the adsorption ability of the MIP that was repeatedly used was investigated, and it showed excellent reproducibility.

  14. Iron crosslinked alginate as novel nanosorbents for removal of arsenic ions and bacteriological contamination from water

    Directory of Open Access Journals (Sweden)

    Priyanka Singh

    2014-07-01

    Full Text Available Fixed-bed column studies were conducted to evaluate performance of Fe (III crosslinked alginate nanoparticles for the removal of pentavalent arsenic ions [As (V] from aqueous environments. The study involved observing the influences of column bed depth, influent As (V concentration and influent flow rates on the removal of arsenic ions. The total adsorbed quantity, equilibrium uptake and total percentage removal of arsenic were determined from the breakthrough curves obtained at different flow rates, initial metal ion concentration and bed heights. The results showed that column demonstrate fairly well performance at the lowest flow rate. Also, column bed capacity and exhaustion time were found to increase with increasing bed height. When initial metal ion concentration was increased from 0.5 mg/L to 1.5 mg/L, the corresponding adsorption bed capacity decreases from 0.066 to 0.022 mg/g. The Bed Depth Service Time (BDST model was used to analyze the experimental data and the model parameters were evaluated. Good agreement of the experimental breakthrough curves with the model predictions was observed.

  15. Prussian blue-coated magnetic nanoparticles for removal of cesium from contaminated environment

    Energy Technology Data Exchange (ETDEWEB)

    Thammawong, Chakrit; Opaprakasit, Pakorn [School of Bio-Chemical Engineering and Technology, Sirindhorn International Institute of Technology (SIIT), Thammasat University (Thailand); Tangboriboonrat, Pramuan [Faculty of Science, Mahidol University, Department of Chemistry (Thailand); Sreearunothai, Paiboon, E-mail: paiboon_sree@siit.tu.ac.th [School of Bio-Chemical Engineering and Technology, Sirindhorn International Institute of Technology (SIIT), Thammasat University (Thailand)

    2013-06-15

    A large amount of radioactive cesium (Cs) has been released into natural environment following the nuclear accident in Fukushima, Japan in 2011. Much effort has been directed at capturing Cs and remediation of the contaminated environment. However, conventional sorbents, such as Prussian blue and zeolites cannot be easily recovered once spread into an open environment. Here, we develop new nano-sorbent based on the magnetic nanoparticles (MNP) functionalized with Prussian blue (PB) that possess both high Cs adsorption capacity (96 mg Cs/g sorbent) and large distribution coefficient (3.2 Multiplication-Sign 10{sup 4} mL/g at 0.5 ppm Cs concentration). The developed sorbents possess good value of saturation magnetization (20 emu/g) allowing for rapid and ease of sorbent separation from the Cs solution after treatment using magnetic field. This Cs magnetic nano-sorbent can offer high potential for the use in large scale remediation of a Cs contaminated environment as well as the possibility of novel Cs decorporation drugs that can be magnetically assisted for accelerated excretion of radiocesium from the human body.

  16. Removal of organic wastewater contaminants in septic systems using advanced treatment technologies

    Science.gov (United States)

    Wilcox, J.D.; Bahr, J.M.; Hedman, C.J.; Hemming, J.D.C.; Barman, M.A.E.; Bradbury, K.R.

    2009-01-01

    The detection of pharmaceuticals and other organic wastewater contaminants (OWCs) in ground water and surface-water bodies has raised concerns about the possible ecological impacts of these compounds on nontarget organisms. On-site wastewater treatment systems represent a potentially significant route of entry for organic contaminants to the environment. In this study, effluent samples were collected and analyzed from conventional septic systems and from systems using advanced treatment technologies. Six of 13 target compounds were detected in effluent from at least one septic system. Caffeine, paraxanthine, and acetaminophen were the most frequently detected compounds, and estrogenic activity was detected in 14 of 15 systems. The OWC concentrations were significantly lower in effluent after sand filtration (p advanced treatment. In general, concentrations in conventional systems were comparable to those measured in previous studies of municipal wastewater treatment plant (WWTP) influent, and concentrations in systems after advanced treatment were comparable to previously measured concentrations in WWTP effluent. These data indicate that septic systems using advanced treatment can reduce OWCs in treated effluent to similar concentrations as municipal WWTPs. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  17. Removal of So2 from Contaminated Air Using a Peat Biofilter

    Directory of Open Access Journals (Sweden)

    Kristina Skemundrytė

    2013-12-01

    Full Text Available About 64 thousand tons of contaminated air is annually released into ambient air. More than 30% of such pollution includes toxic sulfur compounds. The article discusses the properties of biofiltration - biological air cleaning technology. Research was performed using a biofilter produced in the laboratory at Vilnius Gediminas Technical University. During testing, ambient air contaminated with sulfur dioxide was pulled through biomedia with a division of Thiobacillus microorganisms, and calculations of cleaning efficiency were performed. Besides, the efficiency of the charged peat biofilter (changing technical characteristics of the air flow rate, number of layers and value of pollutant concentration, depending on the nature of the investigated sulfur compounds and their concentrations, was determined. The biofilter improves the efficiency of air cleaning when the air flow rate reduces from 0,1 to 0,02 m/s (e.g. when sulfur dioxide is used for treating the air flow rate under the initial concentration C = 15 mg/m³, the efficiency of the filter is equal to E = 96,3%. Article in English

  18. Actual laser removal of black soiling crust from siliceous sandstone by high pulse repetition rate equipment: effects on surface morphology

    Directory of Open Access Journals (Sweden)

    Iglesias-Campos, M. A.

    2016-03-01

    Full Text Available This research project studies the role of pulse repetition rate in laser removal of black soiling crust from siliceous sandstone, and specifically, how laser fluence correlates with high pulse repetition rates in cleaning practice. The aim is to define practical cleaning processes and determine simple techniques for evaluation based on end-users’ perspective (restorers. Spot and surface tests were made using a Q-switched Nd:YAG laser system with a wide range of pulse repetition rates (5–200 Hz, systematically analysed and compared by macrophotography, portable microscope, stereomicroscope with 3D visualizing and area roughness measurements, SEM imaging and spectrophotometry. The results allow the conclusion that for operation under high pulse repetition rates the average of total energy applied per spot on a treated surface should be attendant upon fluence values in order to provide a systematic and accurate description of an actual laser cleaning intervention.En este trabajo se estudia el papel de la frecuencia de repetición en la limpieza láser de costras de contaminación sobre una arenisca silícea, y concretamente, como se relaciona fluencia y frecuencias elevadas en una limpieza real. Se pretende definir un procedimiento práctico de limpieza y determinar técnicas sencillas de evaluación desde el punto de vista de los usuarios finales (restauradores. Para el estudio se realizaron diferentes ensayos en spot y en superficie mediante un equipo Q-switched Nd:YAG con un amplio rango de frecuencias (5–200 Hz, que se analizaron y compararon sistemáticamente mediante macrofotografía, microscopio portátil, estereomicroscopio con visualización 3D y mediciones de rugosidad en área, imágenes SEM y espectrofotometría. Los resultados permiten proponer que, al trabajar con altas frecuencias, la media de la energía total depositada por spot en la superficie debería acompañar los valores de fluencia para describir y comprender mejor una

  19. Laser-based coatings removal

    Energy Technology Data Exchange (ETDEWEB)

    Freiwald, J.G.; Freiwald, D.A. [F2 Associates, Inc., Albuquerque, NM (United States)

    1995-10-01

    Over the years as building and equipment surfaces became contaminated with low levels of uranium or plutonium dust, coats of paint were applied to stabilize the contaminants in place. Most of the earlier paint used was lead-based paint. More recently, various non-lead-based paints, such as two-part epoxy, are used. For D&D (decontamination and decommissioning), it is desirable to remove the paints or other coatings rather than having to tear down and dispose of the entire building. This report describes the use of pulse-repetetion laser systems for the removal of paints and coatings.

  20. Imaging spectroscopy based strategies for ceramic glass contaminants removal in glass recycling.

    Science.gov (United States)

    Bonifazi, Giuseppe; Serranti, Silvia

    2006-01-01

    The presence of ceramic glass contaminants in glass recycling plants reduces production quality and increases production costs. The problem of ceramic glass inspection is related to the fact that its detectable physical and pictorial properties are quite similar to those of glass. As a consequence, at the sorting plant scale, ceramic glass looks like normal glass and is detectable only by specialized personnel. In this paper an innovative approach for ceramic glass recognition, based on imaging spectroscopy, is proposed and investigated. In order to define suitable inspection strategies for the separation between useful (glass) and polluting (ceramic glass) materials, reference samples of glass and ceramic glass presenting different colors, thicknesses, shapes and manufacturing processes have been selected. Reflectance spectra have been obtained using two equipment covering the visible and near infrared wavelength ranges (400-1000 and 1000-1700 nm). Results showed as recognition of glass and ceramic glass is possible using selected wavelength ratios, in both visible and near infrared fields.

  1. Removal of PCB and other halogenated organic contaminants found in ex situ structures

    Science.gov (United States)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Geiger, Cherie L. (Inventor); Coon, Christina (Inventor); Filipek, Laura B. (Inventor); Berger, Cristina M. (Inventor); Milum, Kristen M. (Inventor)

    2009-01-01

    Emulsified systems of a surfactant-stabilized, biodegradable water-in-solvent emulsion with bimetallic particles contained with the emulsion droplets are useful at removing PCBs from ex situ structures. The hydrophobic emulsion system draws PCBs through the solvent/surfactant membrane. Once inside the membrane, the PCBs diffuse into the bimetallic particles and undergo degradation. The PCBs continue to enter, diffuse, degrade, and biphenyl will exit the particle maintaining a concentration gradient across the membrane and maintaining a driving force of the reaction.

  2. The use of capacitive deionization with carbon aerogel electrodes to remove inorganic contaminants from water

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; Fix, D.V.; Mack, G.V.; Pekala, R.W.; Poco, J.F.

    1995-02-17

    The capacitive deionization of water with a stack of carbon aerogel electrodes has been successfully demonstrated for the first time. Unlike ion exchange, one of the more conventional deionization processes, no chemicals were required for regeneration of the system. Electricity was used instead. Water with various anions and cations was pumped through the electrochemical cell. After polarization, ions were electrostatically removed from the water and held in the electric double layers formed at electrode surfaces. The water leaving the cell was purified, as desired.

  3. Removal of Methyl Tert-Butyl Ether (MTBE from Contaminated Water by Photocatalytic Process

    Directory of Open Access Journals (Sweden)

    A Eslami

    2009-06-01

    Full Text Available "nBackground: Methyl tert-butyl ether (MTBE has been commercially used as an octane enhancer to replace tetraethyl lead in gasoline since 1979. The high mobility, water solubility, and resistance to natural attenuation associated with MTBE may re­sult in contamination of ground and surface waters. In this investigation the degradation of aqueous MTBE at relatively high concentrations was studied by UV-vis/TiO2/O2 photocatalytic process. The effect of important operational parameters such as pH, oxygen flow, catalyst loading, and irradiation time were also studied."nMethods:Concentration of MTBE and intermediates such as tert-butyl formate (TBF and tert-butyl alcohol (TBA were meas­ured using a gas chromatograph equipped with flam ionization detector and combined with headspace sampler."nResults: The time required for complete degradation increased from 15 to 150 min, when the initial concentration was in­creased from 10 to 500 mg/L. The first order rate constant for degradation of MTBE from the hydroxyl radical was esti­mated to be 0.266 to 0.033 min-1 as the concentration increased from 10 to 500 mg/L. Study on the overall mineralization moni­tored by total organic carbon (TOC analysis showed that in the initial concentration of 100 mg/L MTBE, complete min­eralization was obtained after 110 min under UV-vis/TiO2/O2 photocatalytic process."nConclusion: The data presented in this paper clearly indicate that UV/TiO2/O2 advanced oxidation process provides an effi­cient treatment alternative for the remediation of MTBE contaminated water.  

  4. Prussian blue caged in alginate/calcium beads as adsorbents for removal of cesium ions from contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Vipin, Adavan Kiliyankil; Hu, Baiyang; Fugetsu, Bunshi, E-mail: hu@ees.hokudai.ac.jp

    2013-08-15

    Highlights: • Prussian blue was encapsulated in calcium/alginate beads. •The Prussian blue encapsulated beads were reinforced using carbon nanotubes. • Adsorption behaviors toward cesium were studied with the aid of appropriate mathematical models. • The beads showed high efficiency over a wide range of pH, potassium and sodium ion concentrations. • Continuous column analysis proved that the beads are suitable for large-scale water treatments. -- Abstract: Prussian blue encapsulated in alginate beads reinforced with highly dispersed carbon nanotubes were prepared for the safe removal of cesium ions from aqueous solutions. Equilibrium and kinetic studies were conducted using different models and the goodness of mathematical fitting of the experimental data on the adsorption isotherms was in the order Langmuir > Freundlich, and that of the kinetic models were in the order of pseudo second order > pseudo first order. Fixed bed adsorption column analysis indicated that the beads can be used for large scale treatment of cesium contaminated water.

  5. Removal and destruction of endocrine disrupting contaminants by adsorption with molecularly imprinted polymers followed by simultaneous extraction and phototreatment

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Alvarez, Paula [Department of Biotechnology, Lund University, P.O. Box 124, 22100 Lund (Sweden); University of Santiago de Compostela, Department of Chemical Engineering, Instituto de Investigaciones Tecnologicas, C/Constantino Candeira, s/n. E-15782 Santiago de Compostela (Spain); Le Noir, Mathieu [Department of Biotechnology, Lund University, P.O. Box 124, 22100 Lund (Sweden); Guieysse, Benoit [Department of Biotechnology, Lund University, P.O. Box 124, 22100 Lund (Sweden); School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, Nanyang Avenue, Singapore 639798 (Singapore)], E-mail: bjguieysse@ntu.edu.sg

    2009-04-30

    This study presents a method to regenerate molecularly imprinted polymers (MIPs) used for the selective removal of endocrine disrupting compounds from aqueous effluents. Regeneration was based on solvent extraction under UV irradiation to regenerate the polymer and the solvent while destroying the contaminants. Acetone was selected as the best solvent for irradiation of estrone (E1), 17{beta}-estradiol (E2) and ethinylestradiol (EE2) using either UVC (254 nm) or UV-vis. A MIP synthesized with E2 as template was then tested for the extraction of this compound from a 2 {mu}g/L loaded aqueous solution. E2 was recovered by 73 {+-} 11% and 46 {+-} 13% from the MIPs and a non-imprinted control polymer synthesized under the same conditions, respectively, after a single step elution with acetone. The irradiated polymers and acetone were reused for an additional extraction-regeneration cycle and showed no capacity decrease.

  6. Anatase TiO2 Nanospindle/Activated Carbon (AC Composite Photocatalysts with Enhanced Activity in Removal of Organic Contaminant

    Directory of Open Access Journals (Sweden)

    Wuyi Zhou

    2012-01-01

    Full Text Available This paper embarks upon the three levels of analysis ranging from nanoscale materials synthesis to combination and functionality. Firstly, we have prepared anatase TiO2 nanospindles with an even length of about 200 nm and a central width of about 25 nm by hydrothermal synthesis method at 100°C for 6 h. Secondly, we have dispersed TiO2 nanospindles on the surface of activated carbon (AC and fabricated TiO2/AC composite via a dip-coating method. Thirdly, the TiO2/AC composite has been studied as the photocatalyst to remove the organic contaminants in the waste water and exhibits excellent degradation rate in comparison with pure anatase TiO2 nanospindles.

  7. Removal of probable human carcinogenic polycyclic aromatic hydrocarbons from contaminated water using molecularly imprinted polymer.

    Science.gov (United States)

    Krupadam, Reddithota J; Khan, Muntazir S; Wate, Satish R

    2010-02-01

    A molecularly imprinted polymer (MIP) adsorbent for carcinogenic polycyclic aromatic hydrocarbons (PAHs) was prepared using a non-covalent templating technique. MIP particles sized from 2 to 5 microm were synthesized in acetonitrile by using six PAHs mix as a template, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. When compared with the non-imprinted polymer (NIP), the MIP showed an excellent affinity towards PAHs in aqueous solution with binding capacity (B(max)) of 687 microg g(-1)MIP, imprinting effect of 6, and a dissociation constant of 24 microM. The MIP exhibited significant binding affinity towards PAHs even in the presence of environmental parameters such as dissolved organic matter (COD) and total dissolved inorganic solids (TDS), suggesting that this material may be appropriate for removal of carcinogenic PAHs. The feasibility of removing PAHs from water by the MIP demonstrated using groundwater spiked with PAHs. In addition, the MIP reusability without any deterioration in performance was demonstrated at least ten repeated cycles.

  8. Application of colloidal gas aphron suspensions produced from Sapindus mukorossi for arsenic removal from contaminated soil.

    Science.gov (United States)

    Mukhopadhyay, Soumyadeep; Mukherjee, Sumona; Hashim, Mohd Ali; Sen Gupta, Bhaskar

    2015-01-01

    Colloidal gas aphron dispersions (CGAs) can be described as a system of microbubbles suspended homogenously in a liquid matrix. This work examines the performance of CGAs in comparison to surfactant solutions for washing low levels of arsenic from an iron rich soil. Sodium Dodecyl Sulfate (SDS) and saponin, a biodegradable surfactant, obtained from Sapindus mukorossi or soapnut fruit were used for generating CGAs and solutions for soil washing. Column washing experiments were performed in down-flow and up flow modes at a soil pH of 5 and 6 using varying concentration of SDS and soapnut solutions as well as CGAs. Soapnut CGAs removed more than 70% arsenic while SDS CGAs removed up to 55% arsenic from the soil columns in the soil pH range of 5-6. CGAs and solutions showed comparable performances in all the cases. CGAs were more economical since it contains 35% of air by volume, thereby requiring less surfactant. Micellar solubilization and low pH of soapnut facilitated arsenic desorption from soil column. FT-IR analysis of effluent suggested that soapnut solution did not interact chemically with arsenic thereby facilitating the recovery of soapnut solution by precipitating the arsenic. Damage to soil was minimal arsenic confirmed by metal dissolution from soil surface and SEM micrograph.

  9. New biodegradable organic-soluble chelating agents for simultaneous removal of heavy metals and organic pollutants from contaminated media

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, Amos, E-mail: Ullmann@eng.tau.ac.il [Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Brauner, Neima; Vazana, Shlomi; Katz, Zhanna [Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Goikhman, Roman [The Hebrew University of Jerusalem, The Robert H. Smith, Faculty of Agriculture, Food and Environment, Rehovot (Israel); Seemann, Boaz; Marom, Hanit [School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Gozin, Michael, E-mail: cogozin@gmail.com [School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

    2013-09-15

    Highlights: • New soil remediation process using phase transition of partially miscible solvents. • Design and synthesis of new bio-degradable, organic soluble chelating agents. • Feasibility tests of the process on authentically polluted sediments and sludge. • Simultaneous removal of toxic metals and organic pollutants was demonstrated. -- Abstract: Advanced biodegradable and non-toxic organic chelators, which are soluble in organic media, were synthesized on the basis of the S,S-ethylenediamine-disuccinate (S,S-EDDS) ligand. The modifications suggested in this work include attachment of a lipophilic hydrocarbon chain (“tail”) to one or both nitrogen atoms of the S,S-EDDS. The new ligands were designed and evaluated for application in the Sediments Remediation Phase Transition Extraction (SR-PTE) process. This novel process is being developed for the simultaneous removal of both heavy metals and organic pollutants from contaminated soils, sediments or sludge. The new chelators were designed to bind various target metal ions, to promote extraction of these ions into organic solvents. Several variations of attached tails were synthesized and tested. The results for one of them, N,N′-bis-dodecyl-S,S-EDDS (C24-EDDS), showed that the metal-ligand complexes are concentrated in the organic-rich phase in the Phase Transition Extraction process (more than 80%). Preliminary applications of the SR-PTE process with the C24-EDDS ligand were conducted also on actually contaminated sludge (field samples). The extraction of five toxic metals, namely, Cd, Cu, Ni, Pb and Zn was examined. In general, the extraction performance of the new ligand was not less than that of S,S-EDDS when a sufficient ligand-to-extracted ion ratio (about 4:1 was applied.

  10. Fenton and Photo-Fenton like at neutral pH for the removal of emerging contaminants in water and wastewater effluents

    OpenAIRE

    De Luca, Antonella

    2016-01-01

    In the last decades, the scientific community has been involved in the research of new kinds of contaminants generally known as of “emerging concern” (CECs). The harmfulness of CECs, even at small concentrations as well as, property of bioaccumulation and persistence, makes them extremely dangerous for the human health. The scientific community is constantly researching about novel treatments able to achieve the removal of these contaminants. Advanced Oxidation Processes (AOPs) are consid...

  11. New biodegradable organic-soluble chelating agents for simultaneous removal of heavy metals and organic pollutants from contaminated media.

    Science.gov (United States)

    Ullmann, Amos; Brauner, Neima; Vazana, Shlomi; Katz, Zhanna; Goikhman, Roman; Seemann, Boaz; Marom, Hanit; Gozin, Michael

    2013-09-15

    Advanced biodegradable and non-toxic organic chelators, which are soluble in organic media, were synthesized on the basis of the S,S-ethylenediamine-disuccinate (S,S-EDDS) ligand. The modifications suggested in this work include attachment of a lipophilic hydrocarbon chain ("tail") to one or both nitrogen atoms of the S,S-EDDS. The new ligands were designed and evaluated for application in the Sediments Remediation Phase Transition Extraction (SR-PTE) process. This novel process is being developed for the simultaneous removal of both heavy metals and organic pollutants from contaminated soils, sediments or sludge. The new chelators were designed to bind various target metal ions, to promote extraction of these ions into organic solvents. Several variations of attached tails were synthesized and tested. The results for one of them, N,N'-bis-dodecyl-S,S-EDDS (C24-EDDS), showed that the metal-ligand complexes are concentrated in the organic-rich phase in the Phase Transition Extraction process (more than 80%). Preliminary applications of the SR-PTE process with the C24-EDDS ligand were conducted also on actually contaminated sludge (field samples). The extraction of five toxic metals, namely, Cd, Cu, Ni, Pb and Zn was examined. In general, the extraction performance of the new ligand was not less than that of S,S-EDDS when a sufficient ligand-to-extracted ion ratio (about 4:1 was applied. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Stimulating the In Situ Activity of Geobacter Species to Remove Uranium from the Groundwater of a Uranium-Contaminated Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R. T.; Vrionis, Helen A.; Ortiz-Bernad, Irene; Resch, Charles T.; Long, Philip E.; Dayvault, R. D.; Karp, Ken; Marutzky, Sammy J.; Metzler, Donald R.; Peacock, Aaron D.; White, David C.; Lowe, Mary; Lovley, Derek R.

    2003-10-01

    The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15 monitoring wells. U(VI) concentrations decreased in as little as 9 days after acetate injection was initiated, and within 50 days uranium had declined below the prescribed treatment level of 0.18 _M in some of the monitoring wells. Analysis of 16S ribosomal DNA (rDNA) sequences and phospholipid fatty acid profiles demonstrated that the initial loss of uranium from the groundwater was associated with an enrichment of Geobacter species in the treatment zone. Fe(II) in the groundwater also increased during this period, suggesting that U(VI) reduction was coincident with Fe(III) reduction. As the acetate injection continued over 50 days there was a loss of sulfate from the groundwater and an accumulation of sulfide and the composition of the microbial community changed. Organisms with 16S rDNA sequences most closely related to those of sulfate reducers became predominant, and Geobacter species became a minor component of the community. This apparent switch from Fe(III) reduction to sulfate reduction as the terminal electron accepting process for the oxidation of the injected acetate was associated with an increase in uranium concentration in the groundwater. These results demonstrate that in situ bioremediation of uranium-contaminated groundwater is feasible but suggest that the strategy should be optimized to better maintain long-term activity of Geobacter species.

  13. Engineering evaluation/cost analysis for the proposed removal of contaminated materials from pad 1 at the Elza Gate site, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    This engineering evaluation/cost analysis (EE/CA) has been prepared in support of the proposed removal action for cleanup of radioactively contaminated concrete and soil beneath a building on privately owned commercial property in Oak Ridge, Tennessee. The property, known as the Elza Gate site, became contaminated with uranium-238, radium-226, thorium-232, thorium-230, and decay products as a result of the Manhattan Engineer District storing uranium ore and ore processing residues at the site in the early 1940s. The US Department of Energy (DOE) has responsibility for cleanup of the property under its Formerly Utilized Sites Remedial Action Program (FUSRAP). The DOE plans to remove the cracked and worn concrete pad and contaminated subsoil beneath the pad, after which the property owner/tenant will provide clean backfill and new concrete. Portions of the pad and subsoil are contaminated and, if stored or disposed of improperly, may represent a potential threat to public health or welfare and the environment. The EE/CA report is the appropriate documentation for the proposed removal action, as identified in guidance from the US Environmental Protection Agency. The objective of the EE/CA report, in addition to identifying the planned removal action, is to document the selection of response activities that will mitigate the potential for release of contaminants from the property into the environment and minimize the related threats to public health or welfare and the environment. 7 refs., 2 figs., 3 tabs.

  14. Engineering evaluation/cost analysis for the proposed removal of contaminated materials from Pad 1 at the Elza Gate site, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This engineering evaluation/cost analysis (EE/CA) has been prepared in support of the proposed removal action for cleanup of radioactively contaminated concrete and soil beneath a building on privately owned commercial property in Oak Ridge, Tennessee. The property, known as the Elza Gate site, became contaminated with uranium-238, radium-226, thorium-232, thorium-230, and decay products as a result of the Manhattan Engineer District storing uranium ore and ore processing residues at the site in the early 1940s. The US Department of Energy (DOE) has responsibility for cleanup of the property under its Formerly Utilized Sites Remedial Action Program (FUSRAP). The DOE plans to remove the cracked and worn concrete pad and contaminated subsoil beneath the pad, after which the property owner/tenant will provide clean backfill and new concrete. Portions of the pad and subsoil are contaminated and, if stored or disposed of improperly, may represent a potential threat to public health or welfare and the environment. The EE/CA report is the appropriate documentation for the proposed removal action, as identified in guidance from the US Environmental Protection Agency. the objective of the EE/CA report, in addition to identifying the planned removal action, is to document the selection of response activities that will mitigate the potential for release of contaminants from the property into the environment and minimize the related threats to public health or welfare and the environment. 7 refs., 2 figs., 3 tabs.

  15. Formation and removal of biomass-derived contaminants in fluidized-bed gasification processes

    Energy Technology Data Exchange (ETDEWEB)

    Kurkela, E. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1996-12-31

    The objectives of this thesis were to examine the effects of the feedstock and the operating conditions of a fluidized-bed gasifier on the formation of tars and nitrogen-containing compounds and to study the effectiveness of the hot gas cleaning methods developed for the removal of particulates, alkali metals, tars and nitrogen-containing compounds. The most essential part of the work was carried out in the pressurized fluidized-bed gasification test facilities composed of an air-blown bubbling fluidized-bed gasifier and subsequent hot gas filter unit. The operation pressure of the test rig could be varied in the range 0.3 - 1.0 MPa and the maximum allowable gasification temperature was 1 050 deg C. The maximum capacity with biomass fuels was 80 kg/h. A wide range of feedstocks from hard coals, lignite and peat to different wood derived fuels and straw were used in the gasification tests. Two different types of ceramic filters were tested in the filter unit connected to the pressurized fluidized-bed gasifier. The filter unit was operated in a temperature range of 400 - 740 deg C. The particulate removal requirements set by the gas turbines were met by both types of filters and with product gases derived from all the feedstocks tested. In addition to the gasification and gas filtration tests, catalytic tar and ammonia decomposition was studied using both laboratory and bench-scale test facilities. Inexpensive calcium-based bulk materials, dolomites and limestones, were efficient tar decomposition catalysts in atmospheric-pressure tests

  16. Influence of plaque biofilm removal on reestablishment of the biocompatibility of contaminated titanium surfaces.

    Science.gov (United States)

    Schwarz, Frank; Papanicolau, Pascal; Rothamel, Daniel; Beck, Brigitte; Herten, Monika; Becker, Jürgen

    2006-06-01

    The aim of the present study was to evaluate the influence of plaque biofilm removal on the mitochondrial activity of human SaOs-2 osteoblasts grown on titanium surfaces. Volunteers wore acrylic splints with structured titanium discs for 72 h to build up plaque biofilms (n = 30). Specimens were randomly instrumented using either (1) an ultrasonic system at two power settings (EMS1, EMS2) + chlorhexidine (CHX), or (2) plastic curettes + CHX. Untreated (NC, n = 10) and sterile (C, n = 10) titanium discs served as controls. Specimens were incubated with SaOs-2 cells for 6 days. Treatment time (T), residual plaque biofilm (RPB)/clean implant surface areas (%), mitochondrial cell activity (MA) (counts/second), and cell morphology (SEM) were assessed. Statistical analysis revealed the following mean scores (+/-SD): RPB areas: P (58.5 +/- 4.9) > EMS1 (38.4 +/- 4.1) > EMS2 (28.3 +/- 2.0); T: PC (292 +/- 30) = EMS1 (244 +/- 24) > EMS2 (199 +/- 25); MA: C (1.544.661 +/- 203.442) > PC (597.559 +/- 566.984) = EMS2 (389.875 +/- 409.300) = EMS1 (356.653 +/- 293.863; n.s.) > NC (138.676 +/- 86.666). In NC and PC groups, cells were predominantly rounded in shape. However, in the EMS groups, some cells had started to spread, showing complete cytoplasmatic extensions of the cell body on the titanium surface. A monolayer of flattened cells was generally observed in the C group. Within the limits of the present study, it was concluded that MA seemed to be impaired by the presence of RPB areas. However, its removal alone might not be the crucial step in the reestablishment of the biocompatibility of titanium surfaces.

  17. Selective removal of carious dentin using a nanosecond pulsed laser with a wavelength of 6.02 μm

    Science.gov (United States)

    Ishii, Katsunori; Saiki, Masayuki; Yasuo, Kenzo; Yamamoto, Kazuyo; Yoshikawa, Kazushi; Awazu, Kunio

    2010-04-01

    Conventional laser light sources for the treatment of a hard tissue in dental (Er:YAG laser, Er,Cr:YSGG laser and CO2 laser etc.) are good for removal of caries. However these lasers cannot achieve to give a selective treatment effect for caries without a side effect for normal tissue. The objective of this study is to develop the less-invasive treatment technique of carious dentin by selective absorption effect using the laser with a wavelength of 6.02 μm which corresponds to an absorption peak of organic matters called amide 1 band. Mid-infrared nanosecond pulsed laser by difference-frequency generation was used for the experiment of selective treatment. A tunable wavelength range, pulse width and repetition rate is from 5.5 to 10 μm, 5 ns and Hz, respectively. The laser with a wavelength of 6.02 μm and predetermined energy parameters was irradiated to the plate of carious dentin model which is made by soaking in lactic acid solution. After laser irradiation, the surface and cross-sectional surface of samples were observed by a scanning electron microscope (SEM). Average power density about 15 W/cm2 realized to excavate a demineralized region (carious dentin model) selectively in a SEM observation. In the same energy condition, serious side effect was not observed on the surface of normal dentin. A wavelength of 6.02 μm realizes a selective excavation of carious dentin. Using 6.02 μm is a novel and promising technique toward to next-generation dental treatment procedure for realizing MI.

  18. Sample contamination with NMP-oxidation products and byproduct-free NMP removal from sample solutions

    Energy Technology Data Exchange (ETDEWEB)

    Cesar Berrueco; Patricia Alvarez; Silvia Venditti; Trevor J. Morgan; Alan A. Herod; Marcos Millan; Rafael Kandiyoti [Imperial College London, London (United Kingdom). Department of Chemical Engineering

    2009-05-15

    1-Methyl-2-pyrrolidinone (NMP) is widely used as a solvent for coal-derived products and as eluent in size exclusion chromatography. It was observed that sample contamination may take place, through reactions of NMP, during extraction under refluxing conditions and during the process of NMP evaporation to concentrate or isolate samples. In this work, product distributions from experiments carried out in contact with air and under a blanket of oxygen-free nitrogen have been compared. Gas chromatography/mass spectrometry (GC-MS) clearly shows that oxidation products form when NMP is heated in the presence of air. Upon further heating, these oxidation products appear to polymerize, forming material with large molecular masses. Potentially severe levels of interference have been encountered in the size exclusion chromatography (SEC) of actual samples. Laser desorption mass spectrometry and SEC agree in showing an upper mass limit of nearly 7000 u for a residue left after distilling 'pure' NMP in contact with air. Furthermore, experiments have shown that these effects could be completely avoided by a strict exclusion of air during the refluxing and evaporation of NMP to dryness. 45 refs., 13 figs.

  19. 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.

  20. Negative transferred arc cleaning: a method for roughening and removing surface contamination from beryllium and other metallic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Castro, R.G.; Hollis, K.J.; Maggiore, C.J.; Ayala, A.; Bartram, B.D. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.; Doerner, R.P. [California Univ., San Diego (United States). Fusion Energy Res.

    2000-04-01

    TA cleaning has been investigated for preparing the surface of beryllium plasma facing components (PFC's) inside of the international thermonuclear experimental reactor (ITER) prior to depositing beryllium by plasma spraying. Plasma spraying of beryllium was evaluated during the ITER engineering design activity (EDA) for in-situ repair and initial fabrication of the beryllium first wall armor. Results have shown that surface roughening of beryllium, during the TA cleaning process, can result in bond strengths greater than 100 MPa between beryllium surfaces and plasma sprayed beryllium. In addition, the TA cleaning process was shown to be an effective method for removing contaminate layers of carbon and tungsten from the surface of beryllium. Investigations have been performed to characterize the different arc-types that occur during the TA cleaning process (type I, I and III arcs) and the effectiveness of the TA cleaning process for potentially removing co-deposited layers of carbon and deuterium from the surface of beryllium, stainless steel and tungsten. (orig.)

  1. Removal and Preconcentration of Pb (II and Cd (II by Zero-Valent Iron Nanoparticles in Contaminated Water

    Directory of Open Access Journals (Sweden)

    Shiralipour

    2015-04-01

    Full Text Available Background Lead (Pb and cadmium (Cd are two of the hazardous metals in the environment due to their acute and chronic effects on human health. Zero-valent iron nanoparticles (ZVINPs are one of the adsorbents proposed as an efficient adsorbent for Pb and Cd. Objectives This study evaluated the quantitative removal efficiency of Pb and Cd ions from contaminated water by ZVINPs. In addition, the capability of ZVINPs as a solid phase extractor for preconcentration and determination of Pb and Cd was investigated. Materials and Methods Four samples, each from different water sources like Well water (Shushtar, Iran, Karoon River (Ahvaz, Iran, Caspian Sea (northern Iran and Persian Gulf (southern Iran were collected. Results The elapsed time for quantitative removal of both Pb and Cd ions was two minutes. This method is applicable in a widespread range of pH and relatively high concentrations of electrolyte (NaCl for the efficient removal (> 99% of Pb and Cd ions in water samples. The adsorption of Pb and Cd ions on ZVINPs was well followed by the Langmuir model. The maximum adsorption amounts of Pb and Cd ions on ZVINPs were 96.5 and 58.3 mg/g, respectively. Limits of detection (LODs of the method for lead and cadmium ions were 0.015 and 0.002 mg/L, respectively. The relative standard deviations for ten replicate determinations (Pb2+ 0.3 mg/L, Cd2+ 0.03 mg/L were below 5%. The enrichment factors were more than 16 and 14 for Pb2+ and Cd2+, respectively. Conclusions The proposed method is simple, fast, cost-effective and safe for the environment.

  2. The polymerization of cyclodextrins modified with silicon (Si) and titanium (Ti) based compounds for the removal and degradation of organic contaminants in water

    OpenAIRE

    2010-01-01

    M.Sc. Water that is free from toxic organic pollutants is essential to human health and the environment at large. Organic contaminants may affect the endocrine system of animals and humans, even when present in very low concentrations (i.e. levels ppb). Current technologies fail to remove these organic compounds efficiently from water at ppb levels. So, the development of new technologies that are capable of removing and degrading organic pollutants from water is crucial. Hence, recently i...

  3. 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.

  4. Chromium removal through biosorption and bioaccumulation by bacteria from tannery effluents contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Mohammad Zubair [Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh (India); Ahmad, Shamim [Microbiology Division, Institute of Ophthalmology, Faculty of Medicine, J.N. Medical College, Aligarh Muslim University, Aligarh (India)

    2011-03-15

    Four bacterial isolates (two resistant and two sensitive to chromium) were isolated from soil contaminated with tannery effluents at Jajmau (Kanpur), India, and were identified by 16S rDNA gene sequencing as Stenotrophomonas maltophilia, Exiguobacterium sp., Pantoea sp., and Aeromonas sp. Biosorption of chromium by dried and living biomasses was determined in the resistant and sensitive isolates. The effect of pH, initial metal concentration, and contact time on biosorption was studied. At pH 2.5 the living biomass of chromium resistant isolate Exiguobacterium sp. ZM-2 biosorbed maximum amount of Cr{sup 6+} (29.8 mg/g) whereas the dried biomass of this isolate biosorbed 20.1 mg/g at an initial concentration of 100 mg/L. In case of chromate sensitive isolates, much difference was not observed in biosorption capacities between their dried and living biomasses. The maximum biosorption of Cr{sup 3+} was observed at pH 4.5. However, biosorption was identical in resistant and sensitive isolates. The data on chromium biosorption were analyzed using Langmuir and Freundlich isotherm model. The biosorption data of Cr{sup 6+} and Cr{sup 3+} from aqueous solution were better fitted in Langmuir isotherm model compared to Freundlich isotherm model. Metal recovery through desorption was observed better with dried biomasses compared to the living biomasses for both types of chromium ions. Bioaccumulation of chromate was found higher in chromate resistant isolates compared to the chromate sensitive isolates. Transmission electron microscopy confirmed the accumulation of chromium in cytoplasm in the resistant isolates. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Laser-induced breakdown spectroscopy for on-line control of selective removal of cobalt binder from tungsten carbide hardmetal by pulsed UV laser surface ablation

    Science.gov (United States)

    Li, Tiejun; Lou, Qihong; Wei, Yunrong; Huang, Feng; Dong, Jingxing; Liu, Jingru

    2001-09-01

    Laser-induced breakdown spectroscopy (LIBS) was successfully used in on-line control of selective removal of cobalt from tungsten carbide hardmetal by pulsed UV laser surface ablation. The dependence of LIBS on number of laser shots was investigated at different laser fluences. The optimal laser fluence of 2.5 J/cm 2 suited for selective removal of cobalt from surface layer of hardmetal was confirmed. The result sample was also subject to different post-examinations to evaluate the feasibility of the application of LIBS in this laser ablation process. It was demonstrated that, monitoring of the emission intensity of cobalt lines could be used as a control parameter for selective removal of cobalt from surface layer of hardmetal by pulsed UV laser. The on-line implementation of the spectroscopic technique LIBS to the surface-ablation process provided important information about the optimal-ablation parameters.

  6. Selective removal of 2,4-dichlorophenol from contaminated water using non-covalent imprinted microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Li Ying [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Li Xin, E-mail: lixin@hit.edu.c [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Li Yuqi [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Qi Jingyao [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Bian Jiang [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Yuan Yixing [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2009-06-15

    A molecularly imprinted polymer (MIP) for selective removal of 2,4-dichlorophenol (2,4-DCP) in water was prepared as microspheres by the reverse microemulsion polymerization method based on the non-covalent interactions between 2,4-DCP, oleic acid, and divinylbenzene in acetonitrile. Microspheres have been characterized by Fourier transform infrared spectrometer (FTIR) and energy dispersive X-ray spectrometer (EDS) studies with evidence of 2,4-DCP linkage in polymer particles and scanning electron microscopy (SEM) to study their morphological properties. The proper adsorption and selective recognition ability of the MIP were studied by an equilibrium-adsorption method. The MIP showed outstanding affinity towards 2,4-DCP in aqueous solution and the optimum pH value for binding has been found around the neutral range. The molecular recognition of 2,4-DCP was analyzed in detail by using molecular modeling software. In addition, by investigating the variation in the adsorption ability of the MIP, it clearly showed excellent reproducibility. - Molecular imprinting has potential as a remediation technology in water treatment.

  7. Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Brodie, E.L.; Joyner, D. C.; Faybishenko, B.; Conrad, M. E.; Rios-Velazquez, C.; Mork, B.; Willet, A.; Koenigsberg, S.; Herman, D.; Firestone, M. K.; Hazen, T. C.; Malave, Josue; Martinez, Ramon

    2011-02-15

    To evaluate the efficacy of bioimmobilization of Cr(VI) in groundwater at the Department of Energy Hanford site, we conducted a series of microcosm experiments using a range of commercial electron donors with varying degrees of lactate polymerization (polylactate). These experiments were conducted using Hanford Formation sediments (coarse sand and gravel) immersed in Hanford groundwater, which were amended with Cr(VI) and several types of lactate-based electron donors (Hydrogen Release Compound, HRC; primer-HRC, pHRC; extended release HRC) and the polylactate-cysteine form (Metal Remediation Compound, MRC). The results showed that polylactate compounds stimulated an increase in bacterial biomass and activity to a greater extent than sodium lactate when applied at equivalent carbon concentrations. At the same time, concentrations of headspace hydrogen and methane increased and correlated with changes in the microbial community structure. Enrichment of Pseudomonas spp. occurred with all lactate additions, and enrichment of sulfate-reducing Desulfosporosinus spp. occurred with almost complete sulfate reduction. The results of these experiments demonstrate that amendment with the pHRC and MRC forms result in effective removal of Cr(VI) from solution most likely by both direct (enzymatic) and indirect (microbially generated reductant) mechanisms.

  8. Selective removal of diclofenac from contaminated water using molecularly imprinted polymer microspheres.

    Science.gov (United States)

    Dai, Chao-Meng; Geissen, Sven-Uwe; Zhang, Ya-Lei; Zhang, Yong-Jun; Zhou, Xue-Fei

    2011-06-01

    A molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP were evaluated using equilibrium binding experiments. Compared to the non-imprinted polymer (NIP), the MIP showed an outstanding affinity towards DFC in an aqueous solution with a binding site capacity (Q(max)) of 324.8 mg/g and a dissociation constant (K(d)) of 3.99 mg/L. The feasibility of removing DFC from natural water by the MIP was demonstrated by using river water spiked with DFC. Effects of pH and humic acid on the selectivity and adsorption capacity of MIP were evaluated in detail. MIP had better selectivity and higher adsorption efficiency for DFC as compared to that of powdered activated carbon (PAC). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance, which is a definite advantage over single-use activated carbon. Copyright © 2011. Published by Elsevier Ltd.

  9. Selective removal of 2,4-dichlorophenol from contaminated water using non-covalent imprinted microspheres.

    Science.gov (United States)

    Li, Ying; Li, Xin; Li, Yuqi; Qi, Jingyao; Bian, Jiang; Yuan, Yixing

    2009-06-01

    A molecularly imprinted polymer (MIP) for selective removal of 2,4-dichlorophenol (2,4-DCP) in water was prepared as microspheres by the reverse microemulsion polymerization method based on the non-covalent interactions between 2,4-DCP, oleic acid, and divinylbenzene in acetonitrile. Microspheres have been characterized by Fourier transform infrared spectrometer (FTIR) and energy dispersive X-ray spectrometer (EDS) studies with evidence of 2,4-DCP linkage in polymer particles and scanning electron microscopy (SEM) to study their morphological properties. The proper adsorption and selective recognition ability of the MIP were studied by an equilibrium-adsorption method. The MIP showed outstanding affinity towards 2,4-DCP in aqueous solution and the optimum pH value for binding has been found around the neutral range. The molecular recognition of 2,4-DCP was analyzed in detail by using molecular modeling software. In addition, by investigating the variation in the adsorption ability of the MIP, it clearly showed excellent reproducibility.

  10. Comparison of the efficiency of mesoporous silicas as absorbents for removing naphthalene from contaminated water

    Directory of Open Access Journals (Sweden)

    Ali Balati

    2014-06-01

    Full Text Available Mesoporous silicas MCM-48 and SBA-15 were synthesized and characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM and Fourier transform infrared (FTIR spectroscopy. Adsorption capacity of two mesoporous silica for removing naphthalene from waste water was determined. The results indicate that under similar conditions, SBA-15 had a better adsorption capacity than MCM-48. In this context, SBA-15 was modified using 3-aminopropyltrimethoxysilane and the effect of contact time, adsorbent dose, solution pH and concentration of naphthalene was investigated in batch adsorption systems. Solution pH appeared to be a key factor affecting the adsorption of naphthalene by NH2-SBA-15. The adsorption experiments revealed that a higher percentage of up to 79.3% of naphthalene was adsorbed in highly acidic media (pH of 2. The equilibrium data were analyzed using Langmuir and Freundlich isotherms and nonlinear regression analysis. This revealed that based on the correlation coefficient (R2 = 0.979 the Langmuir model provided the best fit to the results. The adsorption kinetic was determined using the pseudo-first order, pseudo-second order and Elovich kinetic models. Of the kinetics models tested, the pseudo-first-order equation provided the best fit to the results (R2 = 0.991 of the absorption of naphthalene by the adsorbent.

  11. Formerly utilized MED/AEC sites remedial action program. Removal of a contaminated industrial waste line, Los Alamos, New Mexico. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gunderson, T C; Ahlquist, A J [comps.

    1979-04-01

    In 1977 parts of an abandoned industrial waste line (IWL) that carried laboratory or process chemical and radiochemical wastes were removed from Los Alamos Scientific Laboratory property and from the townsite of Los Alamos in north-central New Mexico. Most of the IWL was removed between 1964 and 1967. Some IWL segments in the townsite, which at that time were buried under newly paved roads, were left for removal during future construction projects involving these roads to minimize traffic problems and road damage, and because they posed no public health hazard. In 1977, prior to impending major road construction in several areas, 400 m (1300 ft) of IWL and two IWL manhole structures were removed from Laboratory and Los Alamos County property. Associated soil contamination was removed to levels considered to be as low as practicable. Contaminated or potentially contaminated material was removed to an approved radioactive waste disposal site on Department of Energy property. Full details of the methods, findings, and as-left conditions are documented in this report.

  12. Tattoo removal in micropigs with low-energy pulses from a Q-switched Nd:YAG laser at 1064 nm

    Science.gov (United States)

    Hu, Xin-Hua; Wooden, W. A.; Cariveau, Mickael J.; Fang, Qiyin; Bradfield, J. F.; Kalmus, Gerhard W.; Vore, S. J.; Sun, Y.

    2001-05-01

    Treatment of pigmented lesions in skin with visible or near- infrared nanosecond (ns) laser pulses often causes significant collateral tissue damage because the current approach uses pulses with energy of 300 mJ or larger. Additionally, this requires large Q-switched laser systems. To overcome these disadvantages, we have investigated a different approach in delivering ns laser pulses for cutaneous lesion treatment. Tattoo removal in an animal model with a focused laser beam from a Q-switched Nd:YAG laser has been investigated in two Yucatan micropigs tattooed with blue, black, green and red pigments. The tattoos were treated with a focused beam of 12-ns pulses at 1064 nm, with different depth under the skin surface, while the micropig was translated to achieve an effect of single pulse per ablation site in the skin. With the pulse energy reduced to a range from 38 to 63 mJ, we found that nearly complete clearance was achieved for blue and black tattoos while clearance of red and green tattoos was incomplete. Analysis of the skin appearance suggested that the pulse energy can be decreased to below 20 mJ which may lead to further reduction of the collateral tissue damage and improve the clearance of red and green tattoos.

  13. The removal of heavy metals from contaminated soil by a combination of sulfidisation and flotation.

    Science.gov (United States)

    Vanthuyne, Mathias; Maes, André

    2002-05-06

    The possibility of removing cadmium, copper, lead and zinc from Belgian loamy soil by a combination of sulfidisation pre-treatment and Denver flotation was investigated. The potentially available--sulfide convertible--metal content of the metal polluted soil was estimated by EDTA (0.1 M, pH 4.65) extraction and BCR sequential extraction. EDTA extraction is better at approximating the metal percentage that is expected to be convertible into a metal sulfide phase, in contrast to the sequential extraction procedure of 'Int. J. Environ. Anal. Chem. 51 (1993) pp. 135-151' in which transition metals present as iron oxide co-precipitates are dissolved by hydroxylammoniumchloride in the second extraction step. To compare the surface characteristics of metal sulfides formed by sulfidisation with those of crystalline metal sulfides, two types of synthetic sediments were prepared and extracted with 0.1 M EDTA (pH 4.65) in anoxic conditions. Separate metal sulfides or co-precipitates with iron sulfide were formed by sulfide conditioning. The Denver flotation of both types of synthetic sediments (kerosene as collector at high background electrolyte concentrations) resulted in similar concentrating factors for freshly formed metal sulfides as for fine-grained crystalline metal sulfides. The selective flotation of metal sulfides after sulfide conditioning of a polluted soil, using kerosene or potassium ethyl xanthate as collectors and MIBC as frother, was studied at high background electrolyte concentrations. The sulfidisations were made in ambient air and inside an anoxic glove box. The concentrating factors corrected by the potentially available metal percentage, determined by 0.1 M EDTA extraction, lie between 2 and 3. The selective flotation of these finely dispersed, amorphous, metal sulfides can possibly be improved by optimising the bubble-particle interaction.

  14. Final report: survey and removal of radioactive surface contamination at environmental restoration sites, Sandia National Laboratories/New Mexico. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, K.A.; Mitchell, M.M. [Brown and Root Environmental, Albuquerque, NM (United States); Jean, D. [MDM/Lamb, Inc., Albuquerque, NM (United States); Brown, C. [Environmental Dimensions, Inc., Albuquerque, NM 87109 (United States); Byrd, C.S. [Sandia National Labs., Albuquerque, NM (United States)

    1997-09-01

    This report describes the survey and removal of radioactive surface contamination at Sandia`s Environmental Restoration (ER) sites. Radiological characterization was performed as a prerequisite to beginning the Resource Conservation and Recovery Act (RCRA) corrective action process. The removal of radioactive surface contamination was performed in order to reduce potential impacts to human health and the environment. The predominant radiological contaminant of concern was depleted uranium (DU). Between October 1993 and November 1996 scanning surface radiation surveys, using gamma scintillometers, were conducted at 65 sites covering approximately 908 acres. A total of 9,518 radiation anomalies were detected at 38 sites. Cleanup activities were conducted between October 1994 and November 1996. A total of 9,122 anomalies were removed and 2,072 waste drums were generated. The majority of anomalies not removed were associated with a site that has subsurface contamination beyond the scope of this project. Verification soil samples (1,008 total samples) were collected from anomalies during cleanup activities and confirm that the soil concentration achieved in the field were far below the target cleanup level of 230 pCi/g of U-238 (the primary constituent of DU) in the soil. Cleanup was completed at 21 sites and no further radiological action is required. Seventeen sites were not completed since cleanup activities wee precluded by ongoing site activity or were beyond the original project scope.

  15. Removal of petroleum hydrocarbons from contaminated groundwater by the combined technique of adsorption onto perlite followed by the O3/H2O2 process.

    Science.gov (United States)

    Moussavi, Gholamreza; Bagheri, Amir

    2012-09-01

    Groundwater contaminated with petroleum hydrocarbons was treated using a combined system of adsorption onto powdered expanded perlite (PEP) followed by the O3/H2O2 process. The pretreatment investigations indicated a high capacity for PEP to remove petroleum hydrocarbons from the contaminated water. An experimental total petroleum hydrocarbon (TPH) adsorption capacity of 275 mg/g PEP was obtained at the natural pH of water. The experimental data fit best with the Freundlich isotherm model and pseudo-second-order adsorption model. The second phase of the experiment evaluated the performance of the O3/H2O2 process in the removal of residual TPH from pretreated water and compared the results with that of raw water. The O3/H202 process attained a maximum TPH removal rate for the pretreated water after 70 min, when 93% of the residual TPH in the effluent of the adsorption system was removed. Overall, the combination of adsorption onto PEP for 100 min and the subsequent treatment with the O3/H2O2 process for 70min eliminated over 99% of the TPH of highly petroleum-contaminated groundwater, with initial values of 162 mg/L. Therefore, we can conclude that the developed treatment system is an appropriate method of remediation for petroleum-contaminated waters.

  16. Evaluation of a recent product to remove lipids and other matrix co-extractives in the analysis of pesticide residues and environmental contaminants in foods

    Science.gov (United States)

    This study demonstrates the application of a novel lipid removal product to the residue analysis of 65 pesticides and 52 environmental contaminants in kale, pork, salmon, and avocado by fast, low pressure gas chromatography – tandem mass spectrometry (LPGC-MS/MS). Sample preparation involves QuEChE...

  17. Steroid concentrations in plasma, whole blood and brain: effects of saline perfusion to remove blood contamination from brain.

    Directory of Open Access Journals (Sweden)

    Matthew D Taves

    Full Text Available The brain and other organs locally synthesize steroids. Local synthesis is suggested when steroid levels are higher in tissue than in the circulation. However, measurement of both circulating and tissue steroid levels are subject to methodological considerations. For example, plasma samples are commonly used to estimate circulating steroid levels in whole blood, but steroid levels in plasma and whole blood could differ. In addition, tissue steroid measurements might be affected by blood contamination, which can be addressed experimentally by using saline perfusion to remove blood. In Study 1, we measured corticosterone and testosterone (T levels in zebra finch (Taeniopygia guttata plasma, whole blood, and red blood cells (RBC. We also compared corticosterone in plasma, whole blood, and RBC at baseline and after 60 min restraint stress. In Study 2, we quantified corticosterone, dehydroepiandrosterone (DHEA, T, and 17β-estradiol (E₂ levels in the brains of sham-perfused or saline-perfused subjects. In Study 1, corticosterone and T concentrations were highest in plasma, significantly lower in whole blood, and lowest in RBC. In Study 2, saline perfusion unexpectedly increased corticosterone levels in the rostral telencephalon but not other regions. In contrast, saline perfusion decreased DHEA levels in caudal telencephalon and diencephalon. Saline perfusion also increased E₂ levels in caudal telencephalon. In summary, when comparing local and systemic steroid levels, the inclusion of whole blood samples should prove useful. Moreover, blood contamination has little or no effect on measurement of brain steroid levels, suggesting that saline perfusion is not necessary prior to brain collection. Indeed, saline perfusion itself may elevate and lower steroid concentrations in a rapid, region-specific manner.

  18. Removal of aflatoxin M1 from artificially contaminated yoghurt by using of new synthesized dehydroacetic acid analogues

    Directory of Open Access Journals (Sweden)

    Frane Delaš

    2012-09-01

    Full Text Available Dehydroacetic acid (DHA and its new synthesized analogues, 4-hydroxy-3-(p-toluoyl-6-(ptolyl-2H-pyrane-2-one (DHT and 5-Bromo-4-hydroxy-3-(p-toluoyl-6-(p-tolyl-2H-pyrane-2-one (BrDHT were tested for removal of aflatoxin M1 (AFM1 from artificially contaminated yoghurt with known concentrations of this toxin to determine the possible use of these chemicals as a means of controlling AFM1 accumulation. Yoghurt from cow’s milk was artificially contaminated with AFM1 at levels of 0.01 to 0.5 μg/L. Yoghurts were stored at 4 °C and 7 °C, respectively, for up to 28 days. Analysis of AFM1 in yoghurt was carried out using two dimensional thin-layer chromatography (TLC - visual estimation. The limit of detection was 0.15 ng/L. The recoveries of AFM1 from the samples spiked at levels of 10, 50, 100, and 500 ng/L were between 80.6 and 107.8 %, respectively. Concentrations of DHA and DHT of 0.01 and 0.03 μmol/L had non or little effect on AFM1 content in experimentally contaminated yoghurt, whereas concentrations higher than 0.05 μmol/L, partially inhibited AFM1 content. The percentage loss of the initial AFM1 amount in yoghurt was estimated by about 15 and 25 %, and 22 to 45 % by the end of storage, respectively. In experiments with 0.01 and 0.05 μmol/L of BrDHT or higher, the concentration of AFM1 was reduced after 28 days by 20 to 95 % or completely, respectively, depending on the time and temperature of deposit. Detection of toxicity of investigated analogues was evaluated by using the brine shrimp (Artemia salina larvae as a screening system for the determination of their sensitivity to some chemicals

  19. Use of an iron-overexchanged clinoptilolite for the removal of Cu2+ ions from heavily contaminated drinking water samples.

    Science.gov (United States)

    Doula, M K; Dimirkou, A

    2008-03-01

    Clinoptilolite, a natural zeolite, was used for the synthesis of a high surface area clinoptilolite-iron oxide system, in order to be used for the removal of Cu2+ ions from drinking water samples. The solid system was obtained by adding natural clinoptilolite in an iron nitrate solution under strongly basic conditions. The Clin-Fe system has specific surface area equal to 151 m2 g(-1) and is fully iron exchanged (Fe/Al=1.23). Batch adsorption experiments were carried out to determine the effectiveness of the Clin and the Clin-Fe system in removal of copper from drinking water. Adsorption experiments were conducted by mixing 1.00 g of each of the substrates with certain volume of water samples contaminated with 10 different Cu concentrations (from 3.15x10(-5) to 315x10(-2) M or from 2.00 to 2000 ppm Cu). For our experimental conditions, the maximum adsorbed Cu amount on Clin was 13.6 mg g(-1) whereas on the Clin-Fe system was 37.5 mg g(-1). The main factors that contribute to different adsorption capacities of the two solids are due to new surface species and negative charge of the Clin-Fe system. In addition, the release of counterbalanced ions (i.e. Ca2+, Mg2+, Na+ and K+) was examined, as well as the dissolution of framework Si and Al. It was found that for the most of the samples the Clin-Fe system releases lower concentrations of Ca, Mg and Na and higher concentrations of K than Clin, while the dissolution of Si/Al was limited. Changes in the composition of water samples, as well as in their pH and conductivities values were reported and explained.

  20. Arsenic removal from contaminated groundwater by membrane-integrated hybrid plant: optimization and control using Visual Basic platform.

    Science.gov (United States)

    Chakrabortty, S; Sen, M; Pal, P

    2014-03-01

    A simulation software (ARRPA) has been developed in Microsoft Visual Basic platform for optimization and control of a novel membrane-integrated arsenic separation plant in the backdrop of absence of such software. The user-friendly, menu-driven software is based on a dynamic linearized mathematical model, developed for the hybrid treatment scheme. The model captures the chemical kinetics in the pre-treating chemical reactor and the separation and transport phenomena involved in nanofiltration. The software has been validated through extensive experimental investigations. The agreement between the outputs from computer simulation program and the experimental findings are excellent and consistent under varying operating conditions reflecting high degree of accuracy and reliability of the software. High values of the overall correlation coefficient (R (2) = 0.989) and Willmott d-index (0.989) are indicators of the capability of the software in analyzing performance of the plant. The software permits pre-analysis, manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. Performance analysis of the whole system as well as the individual units is possible using the tool. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for removal of arsenic from contaminated groundwater.

  1. Removal of heavy metals from artificial metals contaminated water samples based on micelle-templated silica modified with pyoverdin I

    Institute of Scientific and Technical Information of China (English)

    PANADDA Tansupo; WORAKARN Chamonkolpradit; SAKSIT Chanthai; CHALERM Ruangviriyachai

    2009-01-01

    The micelle-templated silica (MTS) was firstly chemically modified with 3-glycidoxypropyl-trimethoxysilane (GPTMS) before immobilized with pyoverdin I. The characteristics of pyoverdin I-anchored onto the modified MTS were investigated using fluorescence, infrared spectra and scanning electron microscopy. The specific surface area of all materials was calculated by Bnmauer, Emmett and Teller (BET) method using nitrogen isotherm adsorption data. As the results, the surface area of commercial silica gel decreased from 609.2 to 405.4 m2/g, it indicated that the pyoverdin I could be immobilized onto the surface of silica solid support. This adsorbent was used for extraction of Fe(Ⅲ), Cu(Ⅱ), Zn(Ⅱ), and Pb(Ⅱ) in artificial metals contaminated water. Experimental conditions for effective adsorption of trace levels of metal ions were optimized with respect to different experimental parameters using batch procedure. The optimum pH value for the removal of metal ions simultaneously on this adsorbent was 4.0. Complete desorption of the adsorbed metal ions from the adsorbent was carded out using 0.25 mol/L of EDTA. The effcct of different cations and anions on the adsorption of these metals on adsorbent was studied and the results showed that the proposed adsorbent could be applied to the highly saline samples and the sample which contains some transition metals.

  2. Effects of modified zeolite on the removal and stabilization of heavy metals in contaminated lake sediment using BCR sequential extraction.

    Science.gov (United States)

    Wen, Jia; Yi, Yuanjie; Zeng, Guangming

    2016-08-01

    Sediment can be applied on land as a soil conditioner. However, toxic substances such as heavy metals within the sediment often lead to soil contamination if no proper management is conducted prior to land application. In order to reduce the bioavailable portion of heavy metals such as Pb, Cu, Zn and Cd, zeolite as a kind of stabilizer was investigated on the effect of metal stabilization in sediment. Zeolite was firstly modified and screened to get the best condition for removal of heavy metals. Results showed that the granulated zeolite with NaCl conditioning had the highest CEC and metal sorption. Using BCR sequential extraction, the selected modified zeolite effectively stabilized Pb, Cu, Zn and Cd in sediment to different extents. It was most suitable for Cd stabilization by reducing its acid exchangeable fraction while increasing the contents of the reducible and residual fractions. Modified zeolite also immobilized Cu, Zn and Pb in sediment by enhancing one stable fraction while decreasing the acid exchangeable fraction.

  3. Isolation of a Halophilic Bacterium, Bacillus sp. Strain NY-6 for Organic Contaminants Removal in Saline Wastewater on Ship

    Institute of Scientific and Technical Information of China (English)

    Jie Gao; Zhenjiang Yu; Xiaohui Zhang; Dan Zhao; Fangbo Zhao

    2013-01-01

    The objective of this research was to examine if certain strains of Bacillus bacteria,could survive in dry powder products and if so,could the bacteria degrade organic contaminants in saline wastewater on a ship.As part of the study,we isolated 7 domesticated strains named NY1,NY2,…,and NY7,the strain NY6 showed to have the best performance for organic matter degradation and could survive in dry powder more than 3 months.NY6 was identified as Bacillus aerius,based on the morphological and physic-chemical properties.Its optimal growth conditions were as follows:salinity was 2%; temperature was 37℃; pH was in 6.5-7.0; best ratio of C∶ N∶ P was 100∶5∶1.The capability of its dry powder for Chemical Oxygen Demand (COD) removal was 800mg COD/g in synthesized marine wastewater with 2% salinity.The spores in the dry powder were 1.972× 108 g1.

  4. Environmental restoration: Integrating hydraulic control of groundwater, innovative contaminant removal technologies and wetlands restoration--A case study at SRS

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, C.M.; Serkiz, S.M.; Adams, J.; Welty, M. (Westinghouse Savannah River Co., Aiken, SC (United States))

    1992-01-01

    The groundwater remediation program at the F and H Seepage Basins, Savannah River Sits (SRS) is a case study of the integration of various environmental restoration technologies at a single waste site. Hydraulic control measures are being designed to mitigate the discharge of groundwater plumes to surface water. One of the primary constituents of the plumes is tritium. An extraction and reinjection scenario is being designed to keep the tritium in circulation in the shallow groundwater, until it can naturally decay. This will be accomplished by extracting groundwater downgradient of the waste sites, treatment, and reinjection of the tritiated water into the water table upgradient of the basins. Innovative in-situ technologies, including electrolytic migration, are being field tested at the site to augment the pump-treat-reinject system. The in-situ technologies target removal of contaminants which are relatively immobile, yet represent long term risks to human health and the environment. Wetland restoration is an integral part of the F and H remediation program. Both in-situ treatment of the groundwater discharging the wetlands to adjust the pH, and replacement of water loss due to the groundwater extraction program ar being considered. Toxicity studies indicate that drought and the effects of low pH groundwater discharge have been factors in observed tree mortality in wetlands near the waste sites.

  5. Micro- and Nano- Porous Adsorptive Materials for Removal of Contaminants from Water at Point-of-Use

    Science.gov (United States)

    Yakub, Ismaiel

    Water is food, a basic human need and a fundamental human right, yet hundreds of millions of people around the world do not have access to clean drinking water. As a result, about 5000 people die each day from preventable water borne diseases. This dissertation presents the results of experimental and theoretical studies on three different types of porous materials that were developed for the removal of contaminants from water at point of use (household level). First, three compositionally distinct porous ceramic water filters (CWFs) were made from a mixture of redart clay and sieved woodchips and processed into frustum shape. The filters were tested for their flow characteristics and bacteria filtration efficiencies. Since, the CWFs are made from brittle materials, and may fail during processing, transportation and usage, the mechanical and physical properties of the porous clays were characterized, and used in modeling designed to provide new insights for the design of filter geometries. The mechanical/physical properties that were characterized include: compressive strength, flexural strength, facture toughness and resistance curve behavior, keeping in mind the anisotropic nature of the filter structure. The measured flow characteristics and mechanical/physical properties were then related to the underlying porosity and characteristic pore size. In an effort to quantify the adhesive interactions associated with filtration phenomena, atomic force microscopy (AFM) was used to measure the adhesion between bi-material pairs that are relevant to point-of-use ceramic water filters. The force microscopy measurements of pull-off force and adhesion energy were used to rank the adhesive interactions. Similarly, the adsorption of fluoride to hydroxyapatite-doped redart clay was studied using composites of redart clay and hydroxyapatite (C-HA). The removal of fluoride from water was explored by carrying out adsorption experiments on C-HA adsorbents with different ratios of

  6. Complete removal of arsenic and zinc from a heavily contaminated acid mine drainage via an indigenous SRB consortium

    Energy Technology Data Exchange (ETDEWEB)

    Le Pape, Pierre, E-mail: pierrelp.hm@gmail.com [Sorbonne Universités – Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), UMR IRD 206, UPMC Université Paris VI, 4 place Jussieu, 75252 Paris cedex 05 (France); Battaglia-Brunet, Fabienne; Parmentier, Marc; Joulian, Catherine; Gassaud, Cindy [French Geological Survey (BRGM), 3 av. Claude Guillemin, 45060, BP 36009, Orléans Cedex 2 (France); Fernandez-Rojo, Lidia [HydroSciences Montpellier, UMR 5569 CNRS-IRD-UM, CC57, 163 rue Auguste Broussonet, 34090 Montpellier (France); Guigner, Jean-Michel; Ikogou, Maya; Stetten, Lucie [Sorbonne Universités – Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), UMR IRD 206, UPMC Université Paris VI, 4 place Jussieu, 75252 Paris cedex 05 (France); Olivi, Luca [Sincrotrone Trieste ELETTRA, I-34012 Trieste (Italy); Casiot, Corinne [HydroSciences Montpellier, UMR 5569 CNRS-IRD-UM, CC57, 163 rue Auguste Broussonet, 34090 Montpellier (France); Morin, Guillaume [Sorbonne Universités – Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), UMR IRD 206, UPMC Université Paris VI, 4 place Jussieu, 75252 Paris cedex 05 (France)

    2017-01-05

    Highlights: • SRB activity is evidenced at acidic pH in acid mine drainage water. • Total arsenic and zinc removal from solution is observed. • As, Zn and Fe are observed to precipitate as biogenic sulfides. • Amorphous orpiment (As{sup III}{sub 2}S{sub 3}) and realgar (As{sup II}S) are observed as main As-bearing sulfides. • A mechanism is proposed for the reduction of As{sub 2}S{sub 3} to AsS by biogenic H{sub 2}S under acidic conditions. - Abstract: Acid mine drainages (AMD) are major sources of pollution to the environment. Passive bio-remediation technologies involving sulfate-reducing bacteria (SRB) are promising for treating arsenic contaminated waters. However, mechanisms of biogenic As-sulfide formation need to be better understood to decontaminate AMDs in acidic conditions. Here, we show that a high-As AMD effluent can be decontaminated by an indigenous SRB consortium. AMD water from the Carnoulès mine (Gard, France) was incubated with the consortium under anoxic conditions and As, Zn and Fe concentrations, pH and microbial activity were monitored during 94 days. Precipitated solids were analyzed using electron microscopy (SEM/TEM-EDXS), and Extended X-Ray Absorption Fine Structure (EXAFS) spectroscopy at the As K-edge. Total removal of arsenic and zinc from solution (1.06 and 0.23 mmol/L, respectively) was observed in two of the triplicates. While Zn precipitated as ZnS nanoparticles, As precipitated as amorphous orpiment (am-As{sup III}{sub 2}S{sub 3}) (33–73%), and realgar (As{sup II}S) (0–34%), the latter phase exhibiting a particular nanowire morphology. A minor fraction of As is also found as thiol-bound As{sup III} (14–23%). We propose that the formation of the As{sup II}S nanowires results from As{sup III}{sub 2}S{sub 3} reduction by biogenic H{sub 2}S, enhancing the efficiency of As removal. The present description of As immobilization may help to set the basis for bioremediation strategies using SRB.

  7. Effects of salinity build-up on the performance of an anaerobic membrane bioreactor regarding basic water quality parameters and removal of trace organic contaminants.

    Science.gov (United States)

    Song, Xiaoye; McDonald, James; Price, William E; Khan, Stuart J; Hai, Faisal I; Ngo, Hao H; Guo, Wenshan; Nghiem, Long D

    2016-09-01

    The effects of elevated inorganic salt concentration on anaerobic membrane bioreactor (AnMBR) treatment regarding basic biological performance and trace organic contaminant (TrOC) removal were investigated. A set of 33 TrOCs were selected to represent pharmaceuticals, steroids, and pesticides in municipal wastewater. Results show potential adverse effects of increase in the bioreactor salinity to 15g/L (as NaCl) on the performance of AnMBR with respect to chemical oxygen demand removal, biogas production, and the removal of most hydrophilic TrOCs. Furthermore, a decrease in biomass production was observed as salinity in the bioreactor increased. The removal of most hydrophobic TrOCs was high and was not significantly affected by salinity build-up in the bioreactor. The accumulation of a few persistent TrOCs in the sludge phase was observed, but such accumulation did not vary significantly as salinity in the bioreactor increased.

  8. Removal of formaldehyde by a pulsed dielectric barrier discharge in dry air in the 20 °C to 300 °C temperature range

    Science.gov (United States)

    Blin-Simiand, N.; Pasquiers, S.; Magne, L.

    2016-05-01

    The influence of the gas mixture temperature, from 20 °C up to 300 °C, on the removal of formaldehyde, diluted at low concentration (less than 800 ppm) in dry air at atmospheric pressure, by a pulsed dielectric barrier discharge (DBD) is studied by means of Fourier transform infrared spectroscopy and micro gas chromatography. Efficient removal of CH2O is obtained and it is found that the characteristic energy, less than 200 J l-1, is a decreasing function of the temperature over the whole range of concentration values under consideration. Byproducts issued from the removal are identified and quantified (CO, CO2, HCOOH, HNO3). Experimental results are analysed using a zero-dimensional simplified DBD-reactor model in order to gain insights on the chemical processes involved. It is shown that the dissociation of the molecule competes with oxidation reactions at low temperature, whereas at high temperature oxidation processes dominate.

  9. Enhanced microbubbles assisted cleaning of diesel contaminated sand.

    Science.gov (United States)

    Agarwal, Ashutosh; Liu, Yu

    2017-07-25

    In this article, we investigated the effect of low intensity pulsed ultrasound (US), temperature and salinity on cleaning efficacy of fine bubbles with diameter <50μm for diesel contaminated sands. About 47% and 76% diesel removal was achieved from 10% (w/w) diesel contaminated fine and medium sands respectively, after 30min treatment with 40kHz low intensity intermittent pulsed US together with MBs in contrast to 41% and 68% diesel removal while treatment with MBs alone. The effect of high temperature was found to be prominent during the initial stages of cleaning. In addition, MBs generated in 599mM saline water efficiently removed 85% diesel from fine sand within 30min in contrast to only 41% diesel removal with MBs in fresh water. This study provides evidence for developing highly efficient MBs based chemical free technology for diesel contaminated sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Comparison of caesium 137 and 134 activity in sheep remaining on upland areas contaminated by Chernobyl fallout with those removed to less active lowland pasture

    Energy Technology Data Exchange (ETDEWEB)

    Howard, B.J.; Beresford, N.A.; Burrow, L.; Shaw, P.V.; Curtis, E.J.C.

    Caesium contamination of vegetation in some upland areas of the United Kingdom after the Chernobyl accident remained persistently higher than many anticipated. Consequently, some sheep continued to graze vegetation containing sufficiently high caesium activity to maintain tissue activity above the limits adopted for slaughter in the United Kingdom (1,000 Bq kg/sup -1/ fresh weight). In this study the caesium activity in lambs remaining on affected upland areas has been compared with that of lambs removed to a lowland site. The former lost very little caesium activity from the end of July to mid-September owing to the persistently high caesium activity of the pasture. The transfer coefficient to lamb muscle (0.79 day kg/sup -1/) was 6 times higher than that previously estimated from lowland field studies. Lambs removed to much less contaminated lowland pasture rapidly lost their Cs activity with an initial biological half life of 10 days.

  11. Preferential removal and immobilization of stable and radioactive cesium in contaminated fly ash with nanometallic Ca/CaO methanol suspension.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Okuda, Tetsuji; Sakita, Shogo; Simion, Cristian

    2014-08-30

    In this work, the capability of nanometallic Ca/CaO methanol suspension in removing and/or immobilizing stable ((133)Cs) and radioactive cesium species ((134)Cs and (137)Cs) in contaminated fly ash was investigated. After a first methanol and second water washing yielded only 45% of (133)Cs removal. While, after a first methanol washing, the second solvent with nanometallic Ca/CaO methanol suspension yielded simultaneous enhanced removal and immobilization about 99% of (133)Cs. SEM-EDS analysis revealed that the mass percent of detectable (133)Cs on the fly ash surface recorded a 100% decrease. When real radioactive cesium contaminated fly ash (containing an initial 14,040Bqkg(-1)(134)Cs and (137)Cs cumulated concentration) obtained from burning wastes from Fukushima were reduced to 3583Bqkg(-1) after treatment with nanometallic Ca/CaO methanol suspension. Elution test conducted on the treated fly ash gave 100BqL(-1) total (134)Cs and (137)Cs concentrations in eluted solution. Furthermore, both ash content and eluted solution concentrations of (134)Cs and (137)Cs were much lower than the Japanese Ministry of the Environment regulatory limit of 8000Bqkg(-1) and 150BqL(-1) respectively. The results of this study suggest that the nanometallic Ca/CaO methanol suspension is a highly potential amendment for the remediation of radioactive cesium-contaminated fly ash.

  12. Application of molecularly imprinted and non-imprinted polymers for removal of emerging contaminants in water and wastewater treatment: a review.

    Science.gov (United States)

    Murray, Audrey; Ormeci, Banu

    2012-11-01

    Over the past decade, several studies have reported trace levels of endocrine disrupting compounds, pharmaceuticals, and personal care products in surface waters, drinking water, and wastewater effluents. There has also been an increased concern about the ecological and human health impact of these contaminants, and their removal from water and wastewater has become a priority. Traditional treatment processes are limited in their ability to remove emerging contaminants from water, and there is a need for new technologies that are effective and feasible. This paper presents a review on recent research results on molecularly imprinted (MIP) and non-imprinted (NIP) polymers and evaluates their potential as a treatment method for the removal of emerging contaminants from water and wastewater. It also discusses the relative benefits and limitations of using MIP or NIP for water and wastewater treatment. MIP, and in particular NIP, offer promising applications for wastewater treatment, but their toxicity and possible health effects should be carefully studied before they are considered for drinking water treatment. More research is also required to determine how best to incorporate MIP and NIP in treatment plants.

  13. Hair removal in hirsute women with normal testosterone levels: a randomized controlled trial of long-pulsed diode laser vs. intense pulsed light

    DEFF Research Database (Denmark)

    Haak, C S; Jensen, Pernille Nymann; Pedersen, A T

    2010-01-01

    Hirsutism is a common disorder in women of reproductive age, and androgen disturbances may aggravate the condition. Limited evidence exists regarding efficacy of hair removal in this specific population and no data are available for patients with verified normal testosterone levels....

  14. Selective removal of cholesteryl ester in atherosclerotic plaque by nanosecond pulsed laser at 5.75 μm for less-invasive laser angioplasty

    Science.gov (United States)

    Ishii, Katsunori; Tsukimoto, Hideki; Hazama, Hisanao; Awazu, Kunio

    2009-02-01

    Laser angioplasty, for example XeCl excimer laser coronary angioplasty (ELCA), has gained more attention for the treatment of serious stenosis blocked by plaque. Low degrees of thermal damage after ablation of atherosclerotic plaques have been achieved by ELCA. However, the large number of risks associated with the procedure, for example, dissections or perforations of the coronary arteries limits its application. A laser treatment technique with high ablation efficiency but low arterial wall injury is desirable. Mid-infrared laser with a wavelength of 5.75 µm is selectively well absorbed in C=O stretching vibration mode of ester bonds in cholesteryl ester. The purpose of this study is to determine the effectiveness of nanosecond pulsed laser at 5.75 µm irradiation for atherosclerotic plaques. We made a study on the irradiation effect to atherosclerotic plaques in tunica intima in a wet condition. In this study, we used a mid-infrared tunable solid-state laser which is operated by difference-frequency generation, with a wavelength of 5.75 µm, a pulse width of 5 ns and a pulse duration of 10 Hz as a treatment light source, and a thoracic aorta of WHHLMI rabbit as an atherosclerosis model. As a result, less-invasive interaction parameters for removing atherosclerotic plaques were confirmed. This study shows that the nanosecond pulsed laser irradiation at 5.75 µm is a powerful tool for selective and less-invasive treatment of atherosclerotic plaques.

  15. Impact of hazardous events on the removal of nutrients and trace organic contaminants by an anoxic-aerobic membrane bioreactor receiving real wastewater.

    Science.gov (United States)

    Phan, Hop V; Hai, Faisal I; McDonald, James A; Khan, Stuart J; van de Merwe, Jason P; Leusch, Frederic D L; Zhang, Ren; Price, William E; Broeckmann, Andreas; Nghiem, Long D

    2015-09-01

    The impacts of four simulated hazardous events, namely, aeration failure, power loss, and chemical shocks (ammonia or bleach) on the performance of an anoxic-aerobic membrane bioreactor (MBR) receiving real wastewater were investigated. Hazardous events could alter pH and/or oxidation reduction potential of the mixed liquor and inhibit biomass growth, thus affecting the removal of bulk organics, nutrients and trace organic contaminants (TrOC). Chemical shocks generally exerted greater impact on MBR performance than aeration/power failure events, with ammonia shock exerting the greatest impact. Compared to total organic carbon, nutrient removal was more severely affected. Removal of the hydrophilic TrOCs that are resistant and/or occur at high concentrations in wastewater was notably affected. The MBR effectively reduced estrogenicity and toxicity from wastewater, but chemical shocks could temporarily increase the endocrine activity of the effluent. Depending on the chemical shock-dose and the membrane flux, hazardous events can exacerbate membrane fouling.

  16. Development of high efficiency silica coated β-cyclodextrin polymeric adsorbent for the removal of emerging contaminants of concern from water.

    Science.gov (United States)

    Bhattarai, Bikash; Muruganandham, M; Suri, Rominder P S

    2014-05-30

    This article reports the removal of several emerging contaminants (ECs) from water using novel adsorbent comprising of β-cyclodextrin (β-CD) coated on silica. Fourteen different adsorbents were synthesized under different experimental conditions using two different crosslinking agents (hexamethylene diisocyanate (HMDI) and epichlorohydrin (EPI)) and co-polymers (glycidoxypropyl trimethoxysilane (GPTS) and aminopropyl triethoxysilane (APTES). The adsorption capacities of the synthesized adsorbents were initially evaluated using 17β-estradiol, perfluorooctanoic acid (PFOA), and bisphenol-A (BPA) as adsorbates. The adsorbent prepared by using HMDI as crosslinking agent with DMSO as solvent was observed to perform the best, and removed more than 90% of 17β-estradiol, PFOA, and BPA. Furthermore, the β-CD loading on the ECs removal was studied which showed that the adsorbate removal increases with increase in loading of β-CD on the substrate. The best adsorbent was resynthesized in seven batches and its performance was reproducible for the removal of ten steroid hormones. The adsorbent showed very good regeneration potential for four successive adsorption-regeneration cycles to remove steroid hormones and PFOA. A plausible mechanism of adsorption is proposed. The synthesized best adsorbent is characterized using FTIR, HR-TEM, TGA and nitrogen adsorption analysis. The TGA results showed that the adsorbent has thermal stability of upto 300°C. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Removal of Cu, Pb and Zn by foam fractionation and a soil washing process from contaminated industrial soils using soapberry-derived saponin: a comparative effectiveness assessment.

    Science.gov (United States)

    Maity, Jyoti Prakash; Huang, Yuh Ming; Hsu, Chun-Mei; Wu, Ching-I; Chen, Chien-Cheng; Li, Chun-Yi; Jean, Jiin-Shuh; Chang, Young-Fo; Chen, Chen-Yen

    2013-08-01

    The feasibility of using the eco-friendly biodegradable surfactant saponin (a plant-based surfactant) from soapberry and surfactin from Bacillus subtilis (BBK006) for the removal of heavy metals from contaminated industrial soil (6511mgkg(-1) copper, 4955mgkg(-1) lead, and 15090mgkg(-1) zinc) by foam fractionation and a soil flushing process was evaluated under variation of fundamental factors (surfactant concentration, pH, temperature and time). The results of latter process showed that 1-2% Pb, 16-17% Cu and 21-24% Zn was removed by surfactin after 48h, whereas the removal of Pb, Cu and Zn was increased from 40% to 47%, 30% to 36% and 16% to 18% in presence of saponin with an increase from 24 to 72h at room temperature by the soil washing process at pH 4. In the foam fractionation process, the metal removal efficiencies were increased with increases in the saponin concentration (0.075-0.15gL(-1)) and time (24-72h), whereas the efficiency was decreased with increasing pH (4-10) and temperature (>40°C). The removal efficiencies of Pb, Cu and Zn were increased significantly from 57% to 98%, 85% to 95% and 55% to 56% with an increase in the flow rate from 0.2 to 1.0Lmin(-1) at 0.15gL(-1) saponin (pH 4 and 30°C). The present investigation indicated that the foam fractionation process is more efficient for the removal of heavy metal from contaminated industrial soil in comparison to the soil washing process. The plant-based eco-friendly biodegradable biosurfactant saponin can be used for environmental cleanup and pollution management.

  18. Double pulse laser induced breakdown spectroscopy: A potential tool for the analysis of contaminants and macro/micronutrients in organic mineral fertilizers.

    Science.gov (United States)

    Nicolodelli, Gustavo; Senesi, Giorgio Saverio; de Oliveira Perazzoli, Ivan Luiz; Marangoni, Bruno Spolon; De Melo Benites, Vinícius; Milori, Débora Marcondes Bastos Pereira

    2016-09-15

    Organic fertilizers are obtained from waste of plant or animal origin. One of the advantages of organic fertilizers is that, from the composting, it recycles waste-organic of urban and agriculture origin, whose disposal would cause environmental impacts. Fast and accurate analysis of both major and minor/trace elements contained in organic mineral and inorganic fertilizers of new generation have promoted the application of modern analytical techniques. In particular, laser induced breakdown spectroscopy (LIBS) is showing to be a very promising, quick and practical technique to detect and measure contaminants and nutrients in fertilizers. Although, this technique presents some limitations, such as a low sensitivity, if compared to other spectroscopic techniques, the use of double pulse (DP) LIBS is an alternative to the conventional LIBS in single pulse (SP). The macronutrients (Ca, Mg, K, P), micronutrients (Cu, Fe, Na, Mn, Zn) and contaminant (Cr) in fertilizer using LIBS in SP and DP configurations were evaluated. A comparative study for both configurations was performed using optimized key parameters for improving LIBS performance. The limit of detection (LOD) values obtained by DP LIBS increased up to seven times as compared to SP LIBS. In general, the marked improvement obtained when using DP system in the simultaneous LIBS quantitative determination for fertilizers analysis could be ascribed to the larger ablated mass of the sample. The results presented in this study show the promising potential of the DP LIBS technique for a qualitative analysis in fertilizers, without requiring sample preparation with chemical reagents.

  19. AbstractApplication of Fenton-like process using iron nano oxides for pyrene removal from contaminated soils

    Directory of Open Access Journals (Sweden)

    S. Jorfi

    2014-05-01

    Conclusion: Fenton oxidation using iron nano oxides under defined optimum conditions and neutral pH, can be a suitable alternative to conventional Fenton for remediation of soils contaminated with pyrene.

  20. KINETICS OF SOLUBLE CHROMIUM REMOVAL FROM CONTAMINATED WATER BY ZEROVALENT IRON MEDIA: CORROSION INHIBITION AND PASSIVE OXIDE EFFECTS. (R825223)

    Science.gov (United States)

    Permeable reactive barriers containing zerovalent iron are being increasingly employed for in situ remediation of groundwater contaminated with redox active metals and chlorinated organic compounds. This research investigated the effect of chromate concentration on...

  1. Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    of the sediment slurry, the other without stirring. The removal of heavy metals was highest in the non-calcareous sediment, where 94% Cd, 91% Zn and 73% Cu were removed after 24 days. The highest removal obtained for the calcareous sediment was 81% Cd, 76% Zn, 75% Pb and 53% Cu after 21 days, with stirred...... was the most stable in these experiments, and thus, the stirred set-up is the best choice for experimental set-up. The order in which the heavy metals were removed from the harbour sediments was Cd>Zn>Pb>Cu....

  2. Advanced Coating Removal Techniques

    Science.gov (United States)

    Seibert, Jon

    2006-01-01

    An important step in the repair and protection against corrosion damage is the safe removal of the oxidation and protective coatings without further damaging the integrity of the substrate. Two such methods that are proving to be safe and effective in this task are liquid nitrogen and laser removal operations. Laser technology used for the removal of protective coatings is currently being researched and implemented in various areas of the aerospace industry. Delivering thousands of focused energy pulses, the laser ablates the coating surface by heating and dissolving the material applied to the substrate. The metal substrate will reflect the laser and redirect the energy to any remaining protective coating, thus preventing any collateral damage the substrate may suffer throughout the process. Liquid nitrogen jets are comparable to blasting with an ultra high-pressure water jet but without the residual liquid that requires collection and removal .As the liquid nitrogen reaches the surface it is transformed into gaseous nitrogen and reenters the atmosphere without any contamination to surrounding hardware. These innovative technologies simplify corrosion repair by eliminating hazardous chemicals and repetitive manual labor from the coating removal process. One very significant advantage is the reduction of particulate contamination exposure to personnel. With the removal of coatings adjacent to sensitive flight hardware, a benefit of each technique for the space program is that no contamination such as beads, water, or sanding residue is left behind when the job is finished. One primary concern is the safe removal of coatings from thin aluminum honeycomb face sheet. NASA recently conducted thermal testing on liquid nitrogen systems and found that no damage occurred on 1/6", aluminum substrates. Wright Patterson Air Force Base in conjunction with Boeing and NASA is currently testing the laser remOval technique for process qualification. Other applications of liquid

  3. Contaminant removal performances on domestic sewage using modified anoxic/anaerobic/oxic process and micro-electrolysis.

    Science.gov (United States)

    Zhou, Jun; Gao, Jingqing; Liu, Yifan; Xiao, Shuai; Zhang, Ruiqin; Zhang, Zhenya

    2013-01-01

    The objective of this study was to enhance removal of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) from domestic sewage in a sequencing batch reactor with added new materials. A modified anoxic/anaerobic/oxic (MAAO) process, integrating a micro-electrolysis (ME) bed in an anoxic tank, and complex biological media (CBM) in anoxic, anaerobic and oxic tanks to treat domestic sewage, and their performances were investigated. The MAAO system was operated at controlled hydraulic retention time (HRT) of 8 h and mixed liquor recirculation (MLR) at 75%. The results showed that the MAAO system could effectively remove COD, TN and TP with average rates of 93%, 80% and 94%, respectively, in March, and 94%, 76% and 91%, respectively, in August. In this system, TP was primarily removed from the anoxic tank regardless of the operational conditions; removal contribution ratios to TP of the anoxic tank reached 56% both in March and August, indicating that the ME bed can effectively enhance phosphorus removal. TN was primarily removed from the anoxic and anaerobic tanks; removal contribution ratios to TN of anoxic and anaerobic tanks reached 36-38% and 37-38%, respectively. The oxic tank had the highest share of COD removal (56% both in March and August) in the removal of phosphorus. The outflow concentrations of COD, TN and TP were 3-46, 7-14 and 0.3-0.5 mg/L, respectively, in March, and 26-49, 9-15 and 0.04-0.1 mg/L, respectively, in August. COD and TN removal performances indicated that the innovative materials of the ME bed and CBM can effectively enhance COD and TN removal.

  4. Effect of pulse current on acidification and removal of Cu, Cd, and As during suspended electrodialytic soil remediation

    DEFF Research Database (Denmark)

    Sun, Tian Ran; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2013-01-01

    , predominately working under overlimiting current density conditions. Soil 1 was sampled from a pile of excavated soil at a site with mixed industrial pollution (Cu and Cd), and soil 2 was sampled from the top layer of a wood preservation site (Cu and As). Results showed that pulse current improved...

  5. Effect of contact time and the use of hydroxypropyl-β-cyclodextrin in the removal of fluorene and fluoranthene from contaminated soils.

    Science.gov (United States)

    Morillo, E; Sánchez-Trujillo, M A; Villaverde, J; Madrid, F; Undabeytia, T

    2014-10-15

    Sorption-desorption experiments of fluorene (FLU) and fluoranthene (FLT) in soils were carried out and correlated to their removal from aged contaminated soils using aqueous solutions in the absence and in the presence of hydroxypropyl-β-cyclodextrin (HPBCD) as the extraction agent. FLU became more resistant to extraction in aged contaminated soils due to its initial adsorption onto the mineral and amorphous soil organic matter (SOM) domains, sites of lower binding energy from which, due to its small size, it could spread towards the condensed SOM as the contact time increased. Therefore, FLU will not be easily desorbed from aged contaminated soils due to physical entrapment mechanisms, even when using HPBCD as extractant, presenting FLU low risks to the environment. On the contrary, FLT was extracted from aged soils in the presence of HPBCD in solutions to a much greater extent than in its absence. Due to its more hydrophobic character FLT sorption in soils was relatively quicker, remaining more or less fixed on hydrophobic sites of the organic matter (OM) with different energies, and therefore the amount of FLT extracted was almost constant for different ageing times. During extraction experiments, the influence of the OM quality of the soils was also highlighted because an inverse proportionality between OM content of soil and extractability of sorbed FLT was observed. It was concluded that soils with lower OM content that had more diagenetically processed OM could block the extraction of FLT more effectively than soils with higher OM content that are less humified. This indicates the need to use not only adsorption-desorption data in contaminant fate and transport models, but also extraction studies in aged contaminated soils and other complementary analytical approaches when assessing soil contamination-related risks. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Use of fluorescence EEM to monitor the removal of emerging contaminants in full scale wastewater treatment plants.

    Science.gov (United States)

    Sgroi, Massimiliano; Roccaro, Paolo; Korshin, Gregory V; Greco, Valentina; Sciuto, Sebastiano; Anumol, Tarun; Snyder, Shane A; Vagliasindi, Federico G A

    2017-02-05

    This study investigated the applicability of different techniques for fluorescence excitation/emission matrices data interpretations, including peak-picking method, fluorescence regional integration and PARAFAC modelling, to act as surrogates in predicting emerging trace organic compounds (ETOrCs) removal during conventional wastewater treatments that usually comprise primary and secondary treatments. Results showed that fluorescence indexes developed using alternative methodologies but indicative of a same dissolved organic matter component resulted in similar predictions of the removal of the target compounds. The peak index defined by the excitation/emission wavelength positions (λex/λem) 225/290nm and related to aromatic proteins and tyrosine-like fluorescence was determined to be a particularly suitable surrogate for monitoring ETOrCs that had very high removal rates (average removal >70%) (i.e., triclosan, caffeine and ibuprofen). The peak index defined by λex/λem=245/440nm and the PARAFAC component with wavelength of the maxima λex/λem=245, 350/450, both identified as humic-like fluorescence, were found remarkably well correlated with ETOrCs such as atenolol, naproxen and gemfibrozil that were moderately removed (51-70% average removal). Finally, the PARAFAC component with wavelength of the maxima λex/λem=<240, 315/380 identified as microbial humic-like fluorescence was the only index correlated with the removal of the antibiotic trimethoprim (average removal 68%).

  7. Coupling granular activated carbon adsorption with membrane bioreactor treatment for trace organic contaminant removal: breakthrough behaviour of persistent and hydrophilic compounds.

    Science.gov (United States)

    Nguyen, Luong N; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D

    2013-04-15

    This study investigated the removal of trace organic contaminants by a combined membrane bioreactor - granular activated carbon (MBR-GAC) system over a period of 196 days. Of the 22 compounds investigated here, all six hydrophilic compounds with electron-withdrawing functional groups (i.e., metronidazole, carbamazepine, ketoprofen, naproxen, fenoprop and diclofenac) exhibited very low removal efficiency by MBR-only treatment. GAC post-treatment initially complemented MBR treatment very well; however, a compound-specific gradual deterioration of the removal of the above-mentioned problematic compounds was noted. While a 20% breakthrough of all four negatively charged compounds namely ketoprofen, naproxen, fenoprop and diclofenac occurred within 1000-3000 bed volumes (BV), the same level of breakthrough of the two neutral compounds metronidazole and carbamazepine did not occur until 11,000 BV. Single-solute isotherm parameters did not demonstrate any discernible correlation individually with any of the parameters that may govern adsorption onto GAC, such as log D, number of hydrogen-bond donor/acceptor groups, dipole moment or aromaticity ratio of the compounds. The isotherm data, however, could differentiate the breakthrough behaviour between negatively charged and neutral trace organic contaminants.

  8. Removal of trace organic contaminants by a membrane bioreactor-granular activated carbon (MBR-GAC) system.

    Science.gov (United States)

    Nguyen, Luong N; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D

    2012-06-01

    The removal of trace organics by a membrane bioreactor-granular activated carbon (MBR-GAC) integrated system were investigated. The results confirmed that MBR treatment can be effective for the removal of hydrophobic (log D>3.2) and readily biodegradable trace organics. The data also highlighted the limitation of MBR in removing hydrophilic and persistent compounds (e.g. carbamazepine, diclofenac, and fenoprop) and that GAC could complement MBR very well as a post-treatment process. The MBR-GAC system showed high removal of all selected trace organics including those that are hydrophilic and persistent to biological degradation at up to 406 bed volumes (BV). However, over an extended period, breakthrough of diclofenac was observed after 7320 BV. This suggests that strict monitoring should be applied over the lifetime of the GAC column to detect the breakthrough of hydrophilic and persistent compounds which have low removal by MBR treatment.

  9. Application of actuator-driven pulsed water jet in aneurysmal subarachnoid hemorrhage surgery: its effectiveness for dissection around ruptured aneurysmal walls and subarachnoid clot removal.

    Science.gov (United States)

    Endo, Hidenori; Endo, Toshiki; Nakagawa, Atsuhiro; Fujimura, Miki; Tominaga, Teiji

    2017-07-01

    In clipping surgery for aneurysmal subarachnoid hemorrhage (aSAH), critical steps include clot removal and dissection of aneurysms without premature rupture or brain injuries. To pursue this goal, a piezo actuator-driven pulsed water jet (ADPJ) system was introduced in this study. This study included 42 patients, who suffered aSAH and underwent clipping surgery. Eleven patients underwent surgery with the assistance of the ADPJ system (ADPJ group). In the other 31 patients, surgery was performed without the ADPJ system (Control group). The ADPJ system was used for clot removal and aneurysmal dissection. The clinical impact of the ADPJ system was judged by comparing the rate of premature rupture, degree of clot removal, and clinical outcomes. Intraoperatively, a premature rupture was encountered in 18.2 and 25.8% of cases in the ADPJ and control groups, respectively. Although the differences were not statistically significant, intraoperative observation suggested that the ADPJ system was effective in clot removal and dissection of aneurysms in a safe manner. Computed tomography scans indicated the achievement of higher degrees of clot removal, especially when the ADPJ system was used for cases with preoperative clot volumes of more than 25 ml (p = 0.047, Mann-Whitney U test). Clinical outcomes, including incidence of postoperative brain injury or symptomatic vasospasm, were similar in both groups. We described our preliminary surgical results using the ADPJ system for aSAH. Although further study is needed, the ADPJ system was considered a safe and effective tool for clot removal and dissection of aneurysms.

  10. Evaluation and study of advanced optical contamination, deposition, measurement, and removal techniques. [including computer programs and ultraviolet reflection analysis

    Science.gov (United States)

    Linford, R. M. F.; Allen, T. H.; Dillow, C. F.

    1975-01-01

    A program is described to design, fabricate and install an experimental work chamber assembly (WCA) to provide a wide range of experimental capability. The WCA incorporates several techniques for studying the kinetics of contaminant films and their effect on optical surfaces. It incorporates the capability for depositing both optical and contaminant films on temperature-controlled samples, and for in-situ measurements of the vacuum ultraviolet reflectance. Ellipsometer optics are mounted on the chamber for film thickness determinations, and other features include access ports for radiation sources and instrumentation. Several supporting studies were conducted to define specific chamber requirements, to determine the sensitivity of the measurement techniques to be incorporated in the chamber, and to establish procedures for handling samples prior to their installation in the chamber. A bibliography and literature survey of contamination-related articles is included.

  11. 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...

  12. Quantification and Removal of Some Contaminating Gases from Acetylene Used to Study Gas-Utilizing Enzymes and Microorganisms

    OpenAIRE

    Hyman, Michael R.; Arp, Daniel J.

    1987-01-01

    Acetylene generated from various grades of calcium carbide and obtained from commercial- and purified-grade acetylene cylinders was shown to contain high concentrations of various contaminants. Dependent on the source of acetylene, these included, at maximal values, H2 (0.023%), O2 (0.779%), N2 (3.78%), PH3 (0.06%), CH4 (0.073%), and acetone (1 to 10%). The concentration of the contaminants in cylinder acetylene was highly dependent on the extent of cylinder discharge. Several conventional me...

  13. Removal of copper from copper-contaminated river water and aqueous solutions using Methylobacterium extorquens modified Erzurum clayey soil

    National Research Council Canada - National Science Library

    Neslihan Celebi; Hayrunnisa Nadaroglu; Ekrem Kalkan; Recep Kotan

    2016-01-01

    ... adsorbent materials for the removal of copper from aqueous solution. The copper concentrations in the samples of the polluted river water and CuCl solutions treated by the natural and bacteria-modified Erzurum clayey soil (ECS...

  14. Assessment of the mechanisms involved in the removal of emerging contaminants by microalgae from wastewater: a laboratory scale study.

    Science.gov (United States)

    Matamoros, Víctor; Uggetti, Enrica; García, Joan; Bayona, Josep M

    2016-01-15

    Aerated batch reactors (2.5L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d(-1) with the complete removal of N-NH4 during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry's law constant higher than 3 10(-1) Pa m(3) mol(-1) (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.

  15. Application of Photo-Fenton Process for COD Removal from Wastewater Produced from Surfactant-Washed  Oil-Contaminated (TPH Soils

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Mehrasbi

    2012-10-01

    Full Text Available Backgrounds and Objectives: The base structure of total petroleum hydrocarbons (TPH is made of hydrogen and carbon. Widespread use, improper disposal and accidental spills of this compounds lead to long term remaining of contaminations such as organic solvents and poly aromatic hydrocarbons (PAHs in the soil and groundwater resources, resulting in critical environmental issues. In this study, an oil-contaminated soil was washed using Tween 80 surfactant and the application of photo-Fenton process (UV/Fe2+/H2O2 for treatment of the produced wastewater was evaluated. Materials and Methods: Tween 80 is a yellow liquid with high viscosity and soluble in water. In order to determine of the photo-Fenton process efficiency, we studied effective variables including Fe concentration, pH, H2O2 concentration, and irradiation time. The UV irradiation source was a medium-pressure mercury vapor lamp (400 w vertically immersed in the solution within 2L volume glass cylindrical reactor.Results: The results showed that efficiency of COD removal depends on the initial Fe concentration, pH, H2O2 concentration and irradiation time. Under optimum conditions, (Fe: 0.1mM, H2O2: 0.43 mM, pH: 3 and UV light irradiation time: 2 hours the removal efficiency of COD was 67.3%. pH plays a crucial role in the photo-Fenton process such that the removal efficiency increased with decreasing of pH. Conclusion: According to the results of this study, under acidic condition, this process is an efficient method for COD removal from the wastewater studied.

  16. Schwertmannite Synthesis through Ferrous Ion Chemical Oxidation under Different H2O2 Supply Rates and Its Removal Efficiency for Arsenic from Contaminated Groundwater.

    Science.gov (United States)

    Liu, Fenwu; Zhou, Jun; Zhang, Shasha; Liu, Lanlan; Zhou, Lixiang; Fan, Wenhua

    2015-01-01

    Schwertmannite-mediated removal of arsenic from contaminated water has attracted increasing attention. However, schwertmannite chemical synthesis behavior under different H2O2 supply rates for ferrous ions oxidation is unclear. This study investigated pH, ferrous ions oxidation efficiency, and total iron precipitation efficiency during schwertmannite synthesis by adding H2O2 into FeSO4 · 7H2O solution at different supply rates. Specific surface area and arsenic (III) removal capacity of schwertmannite have also been studied. Results showed that pH decreased from ~3.48 to ~1.96, ~2.06, ~2.12, ~2.14, or ~2.17 after 60 h reaction when the ferrous ions solution received the following corresponding amounts of H2O2: 1.80 mL at 2 h (treatment 1); 0.90 mL at 2 h and 14 h (treatment 2); 0.60 mL at 2, 14, and 26 h (treatment 3); 0.45 mL at 2, 14, 26, and 38 h (treatment 4), or 0.36 mL at 2, 14, 26, 38, and 50 h (treatment 5). Slow H2O2 supply significantly inhibited the total iron precipitation efficiency but improved the specific surface area or arsenic (III) removal capacity of schwertmannite. For the initial 50.0 μg/L arsenic (III)-contaminated water under pH ~7.0 and using 0.25 g/L schwertmannite as an adsorbent, the total iron precipitation efficiency, specific surface area of the harvested schwertmannite, and schwertmannite arsenic(III) removal efficiency were 29.3%, 2.06 m2/g, and 81.1%, respectively, in treatment 1. However, the above parameters correspondingly changed to 17.3%, 16.30 m2/g, and 96.5%, respectively, in treatment 5.

  17. Thesis Review. Integrated technologies based on the use of activated carbon and radiation to remove contaminants present in landfill leachates

    Directory of Open Access Journals (Sweden)

    M. M. Abdel Daiem

    2013-01-01

    Full Text Available The present work aimed to investigate the eliminationof selected contaminants present in landfillleachates through different technologies such as:adsorption/bioadsortion on ACs, AOPs based on theuse of UV radiation (UV, UV/H2O2, UV/K2S2O8, UV/Na2CO3 and UV/TiO2/AC and gamma radiation.

  18. Role of surface energy and nano-roughness in the removal efficiency of bacterial contamination by nonwoven wipes from frequently touched surfaces.

    Science.gov (United States)

    Edwards, Nicholas W M; Best, Emma L; Connell, Simon D; Goswami, Parikshit; Carr, Chris M; Wilcox, Mark H; Russell, Stephen J

    2017-01-01

    Healthcare associated infections (HCAIs) are responsible for substantial patient morbidity, mortality and economic cost. Infection control strategies for reducing rates of transmission include the use of nonwoven wipes to remove pathogenic bacteria from frequently touched surfaces. Wiping is a dynamic process that involves physicochemical mechanisms to detach and transfer bacteria to fibre surfaces within the wipe. The purpose of this study was to determine the extent to which systematic changes in fibre surface energy and nano-roughness influence removal of bacteria from an abiotic polymer surface in dry wiping conditions, without liquid detergents or disinfectants. Nonwoven wipe substrates composed of two commonly used fibre types, lyocell (cellulosic) and polypropylene, with different surface energies and nano-roughnesses, were manufactured using pilot-scale nonwoven facilities to produce samples of comparable structure and dimensional properties. The surface energy and nano-roughness of some lyocell substrates were further adjusted by either oxygen (O2) or hexafluoroethane (C2F6) gas plasma treatment. Static adpression wiping of an inoculated surface under dry conditions produced removal efficiencies of between 9.4% and 15.7%, with no significant difference (p nonwoven wipe substrates with a surface energy closest to that of the contaminated surface produced the highest E. coli removal efficiency, while the associated increase in fibre nano-roughness abrogated this trend with S. aureus and E. faecalis.

  19. Comparative study of chemical and physical methods for distinguishing between passive and metabolically active mechanisms of water contaminant removal by biofilms.

    Science.gov (United States)

    Adapa, L M; Azimi, Y; Singh, S; Porcelli, D; Thompson, I P

    2016-09-15

    In this study, physical and chemical approaches were employed to distinguish between passive and active mechanisms in biofilms removing contaminants in waste waters and their relative merits were assessed. Respiration, post-exposure recovery and scanning electron microscopic analysis demonstrated that both ultraviolet (UV) treatment (300 mJ/cm(2)) and sodium azide (10 mM) completely inhibited metabolic activity at 5 and 24 h exposure, respectively, whilst not damaging the integrity of the biofilms. Amongst the commonly used chemical inhibitors, only sodium azide showed complete inhibition after 24 h incubation with only about 10% (±4%) of biofilm carbon released into the bulk solution, compared to 33-41% (±8%) when exposed to 5 mM and 10 mM 2,4-dinitrophenol (DNP) and 69-80% (±5%) when exposed to 2% and 5% w/v formalin, respectively. Biofilm inhibition with UV and sodium azide was found to be equally effective at inhibiting biofilms for treatment of triethanolamine (TEA) and benzotriazole (BTA): the results confirming that the dominant removal mechanism was biodegradation. However, the rates of glucose removal by sodium azide-inhibited biofilms were similar to controls, suggesting that chemical inhibitors were not effective for distinguishing the removal mechanisms of simple sugars. Statistically similar amounts of metal were removed by biofilms treated with UV and sodium azide in zinc, copper and cadmium single-systems: the results indicated that the removal mechanism is predominantly a passive biosorption process.

  20. Effect of EDTA and Tannic Acid on the Removal of Cd, Ni, Pb and Cu from Artificially Contaminated Soil by Althaea rosea Cavan.

    Science.gov (United States)

    Cay, Seydahmet; Uyanik, Ahmet; Engin, Mehmet Soner; Kutbay, Hamdi Guray

    2015-01-01

    In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.

  1. Reclamation of heavy metals from contaminated soil using organic acid liquid generated from food waste: removal of Cd, Cu, and Zn, and soil fertility improvement.

    Science.gov (United States)

    Dai, Shijin; Li, Yang; Zhou, Tao; Zhao, Youcai

    2017-06-01

    Food waste fermentation generates complicated organic and acidic liquids with low pH. In this work, it was found that an organic acid liquid with pH 3.28 and volatile low-molecular-weight organic acid (VLMWOA) content of 5.2 g/L could be produced from food wastes after 9-day fermentation. When the liquid-to-solid ratio was 50:1, temperature was 40 °C, and contact time was 0.5-1 day, 92.9, 78.8, and 52.2% of the Cd, Cu, and Zn in the contaminated soil could be washed out using the fermented food waste liquid, respectively. The water-soluble, acid-soluble, and partly reducible heavy metal fractions can be removed after 0.5-day contact time, which was more effective than that using commercially available VLMWOAs (29-72% removal), as the former contained microorganisms and adequate amounts of nutrients (nitrogen, phosphorous, and exchangeable Na, K, and Ca) which favored the washing process of heavy metals. It is thus suggested that the organic acid fractions from food waste has a considerable potential for reclaiming contaminated soil while improving soil fertility.

  2. Efficacy, tolerability, and safety of a long-pulsed ruby laser system in the removal of unwanted hair.

    Science.gov (United States)

    Polderman, M C; Pavel, S; le Cessie, S; Grevelink, J M; van Leeuwen, R L

    2000-03-01

    Unwanted hair growth is a common, usually physiologic phenomenon. In this study the efficacy and tolerability of a long-pulsed ruby laser system was compared with needle electrolysis and hot wax on three parts of the body. Thirty volunteers were treated three times on the forearm (n = 10), on the face (n = 10), or in the pubic area (n = 10) with 25 J/cm2 laser, 40 J/cm2 laser, needle electrolysis, and hot wax therapy. The 25 J/cm2 and 40 J/cm2 laser treated sites showed a statistically significant decrease (38% and 49%, respectively) in the number of hairs at the first visit after the last treatment compared to the pretreatment hair counts. No significant decrease was observed in the needle electrolysis and hot wax treated sites. Laser therapy yielded better results on the forearm than on the face or pubic area and was scored as the least painful. The long-pulsed ruby laser is a promising, well-tolerated method of epilation.

  3. 脉冲电晕结合Ca(OH)2吸收法脱硫脱硝%Removal of SO2 and NOx by Pulsed Corona Combined with in situ Ca(OH)2 Absorption

    Institute of Scientific and Technical Information of China (English)

    黄立维; 党永霞

    2011-01-01

    Removal of SO2 and NOx by pulsed corona combined with in situ alkali absorption was experimentally investigated. In the reactor, a plate-wire-plate combination is devised for generating pulsed corona and then alkaline absorbent slurries were introduced into the reactor by a continuous band conveying system to capture the gaseous reaction products. It was found that both SO2 and NO could be removed by corona combined with in situ alkali absorption. The removal of SO2 increased to 75% with the corona discharge, compared with 60% removal only with Ca(OH)2 absorption. About 40% removal of NO was reached by pulsed corona combined with in situ Ca(OH)2 absorption. It was found that SO2 and NO in the gas stream are oxidized to SO3 and NO2 by pulsed corona respectively, and then absorbed by the alkali in the reactor. The removals of SO2 as well as NO were higher with Ca(OH)2 as the absorbent, compared with using CaCO3 or ZnO.

  4. Uso de fosfato para remoção de arsênio de solo contaminado Use of phosphate for removal of arsenic from contaminated soil

    Directory of Open Access Journals (Sweden)

    Waleska G. P. da Silva

    2010-01-01

    hazardous residues in its area. One of the stages of the zinc extraction process consists of the addition of arsenic trioxide for the removal of impurities and the soil was contaminated with arsenic from areas near sites where the hazardous residues were disposed. In this context, this study evaluated the ex situ remediation technique through removal by leaching the contaminated soil with arsenic, and the treatment of the effluent generated. The fractioning showed that the pH reduction increased the arsenic retention. The potassium dihydrogenophosphate concentration in 0.4 mol L-1 seemed to be efficient in the removal of the arsenic present in the contaminated soil, achieving the dissolution of about 70% of this element at pH 6.2. The ferric chloride was more efficient than the aluminum sulphate for the removal, through coagulation, of the arsenic present in the effluent generated in the soil leaching.

  5. Quantification and removal of some contaminating gases from acetylene used to study gas-utilizing enzymes and microorganisms.

    Science.gov (United States)

    Hyman, M R; Arp, D J

    1987-02-01

    Acetylene generated from various grades of calcium carbide and obtained from commercial- and purified-grade acetylene cylinders was shown to contain high concentrations of various contaminants. Dependent on the source of acetylene, these included, at maximal values, H(2) (0.023%), O(2) (0.779%), N(2) (3.78%), PH(3) (0.06%), CH(4) (0.073%), and acetone (1 to 10%). The concentration of the contaminants in cylinder acetylene was highly dependent on the extent of cylinder discharge. Several conventional methods used to partially purify cylinder acetylene were compared. A small-scale method for extensively purifying acetylene is described. An effect of acetylene quality on acetylene reduction assays conducted with purified nitrogenase from Azotobacter vinelandii was demonstrated.

  6. Biodegradation of biphenyl and removal of 2-chlorobiphenyl by Pseudomonas sp. KM-04 isolated from PCBs-contaminated mine impacted soil

    Science.gov (United States)

    Nam, I.; Chon, C.; Kim, J.; Kim, Y.

    2013-12-01

    The aim of the present study is to remediate the PCBs contaminated mine soil using microcosm study. For that, the naturally occurring microorganisms are stimulated and enriched in soil itself by supplementing biphenyl as well as benzoic acid. As a result the biphenyl degrading organisms are induced to degrade the PCBs contamination. From the stimulated soil, the biphenyl degrading organisms are isolated and degraded metabolites are elucidated. Pseudomonas sp. strain KM-04 was isolated from PCBs-contaminated soil in a coal mine-impacted area, and identification of bacteria was done by sequencing the 16S rRNA gene analysis. The growth of Pseudomonas sp. strain KM-04 using biphenyl as the sole carbon source was investigated by culturing in 100-mL Erlenmeyer flasks containing 10 ml sterilized MSM and 10 μg/ml biphenyl, and the ability of KM-04 to remove biphenyl and 2-chlorobiphenyl from mine soil was investigated. Metabolite formation was confirmed by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometric analysis. Pseudomonas sp. strain KM-04 uses biphenyl as a sole carbon and energy source, and resting cells convert biphenyl to its metabolic intermediates, including dihydroxybiphenyl, 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid, and benzoic acid. Incubation of real soil collected from abandoned mine areas with resting cells of Pseudomonas sp. strain KM-04 for 10 days resulted in the 98.5 % of biphenyl and 82.3 % of 2-chlorobiphenyl in a slurry system. The ability of the Pseudomonas sp. strain KM-04 to bioremediate biphenyl and 2-chlorobiphenyl from abandoned mine soil was examined using soil microcosm studies under laboratory conditions. Treatment of mine soil with the Pseudomonas sp. strain KM-04 for 15 days resulted in 87.1 % reduction in biphenyl and 68.7 % in 2-chlorobiphenyl contents. The results suggest that Pseudomonas sp. strain KM-04 is a potential candidate for the biological removal of biphenyl and chlorinated derivatives

  7. Soil washing in combination with homogeneous Fenton-like oxidation for the removal of 2,4,4'-trichlorodiphenyl from soil contaminated with capacitor oil.

    Science.gov (United States)

    Ma, Xiao-Hong; Zhao, Ling; Lin, Zhi-Rong; Dong, Yuan-Hua

    2016-04-01

    Detoxification by chemical oxidation of polychlorinated biphenyls (PCBs) in contaminated soils is very difficult and inefficient because PCBs typically associate with the solid phase or exist as non-aqueous-phase liquids due to their low solubility and slow desorption rates, and thus, they are difficult to remove from soils by using traditional, water-based elution techniques. Surfactant can enhance washing efficiency of PCBs from contaminated soils. This study used Brij 58, Brij 30, Tween 80, and 2-hydroxypropyl-β-cyclodextrin (HPCD) to solubilize 2,4,4'-trichlorodiphenyl (PCB28) from soil contaminated with capacitor oil into solution. The feasibility of PCB28 oxidation in soil washing wastewater through a Fe(3+)-catalyzed Fenton-like reaction was subsequently examined. Washing with 10 g L(-1) Brij 58 solution showed the highest extraction efficiency (up to 61.5 %) compared with that of the three other surfactants. The total concentration of PCB28 in contaminated soil at 25 °C after 48-h extraction was 286 mg L(-1). In contrast to conditions in which no washing agent was added, addition of the four washing agents decreased the efficiency of PCB28 degradation by the Fenton-like reaction, with the decrease due to addition of 10 g L(-1) Brij 58 solution being the smallest. The optimal concentration of H2O2 for preventing its useless decomposition was found to be 50 mM. The efficiency of PCB28 removal was lower when the initial concentration of PCB28 treated in the Fenton-like reaction was higher. The degradation efficiencies of PCB28 at initial concentrations of 0.1, 10, and 176 mg L(-1) in 10 g L(-1) Brij 58 solution at 25 °C and pH 3.0 and 9 h of reaction using 50 mM H2O2 were 64.1, 42.0, and 34.6 %, respectively. This result indicates that soil washing combined with Fenton-like oxidation may be a practical approach for the remediation of PCB-contaminated soil.

  8. Inactivation of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice by pulsed light. Influence of initial contamination and required reduction levels.

    Science.gov (United States)

    Ferrario, Mariana I; Guerrero, Sandra N

    2017-07-17

    The purpose of this study was to analyze the response of different initial contamination levels of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice as affected by pulsed light treatment (PL, batch mode, xenon lamp, 3pulses/s, 0-71.6J/cm(2)). Biphasic and Weibull frequency distribution models were used to characterize the relationship between inoculum size and treatment time with the reductions achieved after PL exposure. Additionally, a second order polynomial model was computed to relate required PL processing time to inoculum size and requested log reductions. PL treatment caused up to 3.0-3.5 log reductions, depending on the initial inoculum size. Inactivation curves corresponding to PL-treated samples were adequately characterized by both Weibull and biphasic models (Radj(2) 94-96%), and revealed that lower initial inoculum sizes were associated with higher inactivation rates. According to the polynomial model, the predicted time for PL treatment increased exponentially with inoculum size. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Bio-removal of mixture of benzene,toluene,ethylbenzene,and xylenes/total petroleum hydrocarbons/trichloroethylene from contaminated water

    Institute of Scientific and Technical Information of China (English)

    SHIM Hojae; MA Wei; LIN Aijun; CHAN Kaicho

    2009-01-01

    Four pure cultures were isolated from soil samples potentially contaminated with gasoline compounds either at a construction site near a gas station in Fai Chi Kei,Macau SAR or in the northern parts of China (Beijing,and Hebei and Shandong provinces).The effects of different concentrations of benzene,toluene,ethylbenzene,and three isomers (ortho-,meta-,and para-) of xylene (BTEX),total petroleum hydrocarbons (TPH),and trichloroethylene (TCE),when they were present in mixtures,on the bio-removal efficiencies of microbial isolates were investigated,together with their interactions during the bio-removal process.When the isolates were tested for the BTEX (50-350 mg/L)/TPH (2000 mg/L) mixture,BTEoX in BTEoX/TPH mixture was shown with higher bio-removal efficiencies,while BTEmX in BTEmX/TPH mixture was shown with the lowest,regardless of isolates.The TPH in BTEmX/TPH mixture,on the other hand,were generally shown with higher bio-removal efficiencies compared to when TPH mixed with BTEoX and BTEpX.When these BTEX mixtures (at 350 mg/L) were present with TCE (5-50 mg/L),the stimulatory effect of TCE toward BTEoX bio-removal was observed for BTEoX/TCE mixture,while the inhibitory effect of TCE toward BTEmX for BTEmX/TCE mixture.The bio-removal efficiency for TPH was shown lower in TPH (2000 mg/L)/TCE (5-50 mg/L) mixtures compared to TPH present alone,implying the inhibitory effect of TCE toward TPH bio-removal.For the mixture of BTEX (417 mg/L),TPH (2000 mg/L) along with TCE (5-50 mg/L),TCE was shown co-metabolically removed more efficiently at 15 mg/L,probably utilizing BTEX and/or TPH as primary substrates.

  10. AOPs with ozone and UV radiation in drinking water: contaminants removal and effects on disinfection byproducts formation.

    Science.gov (United States)

    Collivignarelli, C; Sorlini, S

    2004-01-01

    In this study, the advanced oxidation with ozone and UV radiation (with two low pressure UV lamps, at 254 and 185 nm wavelength) were experimented on a surface water in order to study the removal of two odorous compounds (geosmin and 2-methylisoborneol) and a pesticide (metolachlor), the influence on organic compounds (UV absorbance and THM precursors) and bromate formation. Different batch tests were performed with ozone concentration up to 10 mg/L, UV dose up to 14,000 J/m2 and a maximum contact time of 10 minutes. The main results show that metolachlor can be efficiently removed with ozone alone while for geosmin and MIB a complete removal can be obtained with the advanced oxidation of ozone (with concentration of 1.5-3 mg/L and contact time of 2-3 minutes) with UV radiation (with doses of 5,000-6,000 J/m2). As concerns the influence on the organic precursors, all the experimented processes show a medium removal of about 20-40% for UV absorbance and 15-30% for THMFP (trihalomethanes formation potential). As concerns bromate formation, the advanced oxidation of ozone/UV 254 nm shows a bromate formation that is about 40% lower with respect to conventional oxidation with ozone.

  11. Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    Electrodialytic removal of heavy metals from different harbour sediments was investigated. Electrodialytic remediation experiments in laboratory scale were made with calcareous and non-calcareous harbour sediments. Two different experimental set-ups were used for the study, one with stirring of t...

  12. Response of Lemna gibba L. to high and environmentally relevant concentrations of ibuprofen: Removal, metabolism and morpho-physiological traits for biomonitoring of emerging contaminants.

    Science.gov (United States)

    Di Baccio, D; Pietrini, F; Bertolotto, P; Pérez, S; Barcelò, D; Zacchini, M; Donati, E

    2017-01-16

    The increasing worldwide consumption of pharmaceuticals and personal care products such as ibuprofen (IBU) is leading to the widespread and persistent occurrence of these chemicals and their transformation products in soils and waters. Although at low concentrations, the continuous discharge of these micropollutants and the incomplete removal by the actual wastewater treatments can provoke accumulation in the environment with risks for the trophic chain. Non-target organisms as duckweed can be used for the environmental monitoring of pharmaceutical emerging contaminants. In this work, plants of Lemna gibba L. were exposed to high (0.20 and 1mgL(-1)) and environmentally relevant (0.02mgL(-1)) concentrations of IBU to investigate their removal and metabolization capacity. The main oxidized IBU metabolites in humans (hydroxy-IBU and carboxy-IBU) were determined in the intact plants and in the growth solutions, together with non-destructive physiological parameters and phytotoxic indicators. The IBU uptake increased with the increasing of IBU concentration in the medium, but the relative accumulation of the pharmaceutical and generation of hydroxy-IBU was higher in presence of the lower IBU treatments. Carboxy-IBU was not found in the plant tissue and solutions. The changes observed in growth and photosynthetic performances were not able to induce phyto-toxic effects. Apart from a mean physical-chemical degradation of 8.2%, the IBU removal by plants was highly efficient (89-92.5%) in all the conditions tested, highlighting the role of L. gibba in the biodegradation of emerging contaminants.

  13. Development of an Integrated Multi-Contaminant Removal Process Applied to Warm Syngas Cleanup for Coal-Based Advanced Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Howard

    2010-11-30

    This project met the objective to further the development of an integrated multi-contaminant removal process in which H2S, NH3, HCl and heavy metals including Hg, As, Se and Cd present in the coal-derived syngas can be removed to specified levels in a single/integrated process step. The process supports the mission and goals of the Department of Energy's Gasification Technologies Program, namely to enhance the performance of gasification systems, thus enabling U.S. industry to improve the competitiveness of gasification-based processes. The gasification program will reduce equipment costs, improve process environmental performance, and increase process reliability and flexibility. Two sulfur conversion concepts were tested in the laboratory under this project, i.e., the solventbased, high-pressure University of California Sulfur Recovery Process High Pressure (UCSRP-HP) and the catalytic-based, direct oxidation (DO) section of the CrystaSulf-DO process. Each process required a polishing unit to meet the ultra-clean sulfur content goals of <50 ppbv (parts per billion by volume) as may be necessary for fuel cells or chemical production applications. UCSRP-HP was also tested for the removal of trace, non-sulfur contaminants, including ammonia, hydrogen chloride, and heavy metals. A bench-scale unit was commissioned and limited testing was performed with simulated syngas. Aspen-Plus®-based computer simulation models were prepared and the economics of the UCSRP-HP and CrystaSulf-DO processes were evaluated for a nominal 500 MWe, coal-based, IGCC power plant with carbon capture. This report covers the progress on the UCSRP-HP technology development and the CrystaSulf-DO technology.

  14. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    2011-01-01

    and chromophore. Longer wavelengths and cooling are safer for patients with darker skin types. Hair removal with lasers and IPL sources are generally safe treatment procedures when performed by properly educated operators. However, safety issues must be addressed since burns and adverse events do occur. New...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair...... systems. Evidence has been found for long-term hair removal efficacy beyond 6 months after repetitive treatments with alexandrite, diode, and long-pulse Nd:YAG lasers, whereas the current long-term evidence is sparse for IPL devices. Treatment parameters must be adjusted to patient skin type...

  15. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    and chromophore. Longer wavelengths and cooling are safer for patients with darker skin types. Hair removal with lasers and IPL sources are generally safe treatment procedures when performed by properly educated operators. However, safety issues must be addressed since burns and adverse events do occur. New...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair...... systems. Evidence has been found for long-term hair removal efficacy beyond 6 months after repetitive treatments with alexandrite, diode, and long-pulse Nd:YAG lasers, whereas the current long-term evidence is sparse for IPL devices. Treatment parameters must be adjusted to patient skin type...

  16. Identification and Removal of High Frequency Temporal Noise in a Nd:YAG Macro-Pulse Laser Assisted with a Diagnostic Streak Camera

    Energy Technology Data Exchange (ETDEWEB)

    Kent Marlett, Bechtel Nevada; Ke-Xun Sun Bechtel Nevada

    2004-09-23

    This paper discusses the use of a reference streak camera (SC) to diagnose laser performance and guide modifications to remove high frequency noise from Bechtel Nevada's long-pulse laser. The upgraded laser exhibits less than 0.1% high frequency noise in cumulative spectra, exceeding National Ignition Facility (NIF) calibration specifications. Inertial Confinement Fusion (ICF) experiments require full characterization of streak cameras over a wide range of sweep speeds (10 ns to 480 ns). This paradigm of metrology poses stringent spectral requirements on the laser source for streak camera calibration. Recently, Bechtel Nevada worked with a laser vendor to develop a high performance, multi-wavelength Nd:YAG laser to meet NIF calibration requirements. For a typical NIF streak camera with a 4096 x 4096 pixel CCD, the flat field calibration at 30 ns requires a smooth laser spectrum over 33 MHz to 68 GHz. Streak cameras are the appropriate instrumentation for measuring laser amplitude noise at these very high frequencies since the upper end spectral content is beyond the frequency response of typical optoelectronic detectors for a single shot pulse. The SC was used to measure a similar laser at its second harmonic wavelength (532 nm), to establish baseline spectra for testing signal analysis algorithms. The SC was then used to measure the new custom calibration laser. In both spatial-temporal measurements and cumulative spectra, 6-8 GHz oscillations were identified. The oscillations were found to be caused by inter-surface reflections between amplifiers. Additional variations in the SC spectral data were found to result from temperature instabilities in the seeding laser. Based on these findings, laser upgrades were made to remove the high frequency noise from the laser output.

  17. A Study of Removing Chlorobenzene by the Synergistic Effect of Catalysts and Dielectric-Barrier Discharge Driven by Bipolar Pulse-Power

    Institute of Scientific and Technical Information of China (English)

    LI Duan; ZHANG Di; WU Yan; LI Jie; LI Guofeng

    2008-01-01

    In this study, the improvement in the removal of chlorobenzene (C6H5Cl) in the air was investigated by combining dielectric barrier discharge (DBD) driven by bipolar pulse-power with catalysts. Molecular sieve 4A (MS-4A) and MnO2/γ-Al2O3 (MnO2/ALP) as two kinds of catalysts were tested at different positions in a DBD reactor. Catalysts were located either in the discharging area between two electrodes, or just behind the discharging area (in the afterglow area) closed to the outlet. The results indicated that DBD reactor with a bipolar pulse power-supply produced strong instant discharge and energetic particles, which can effectively activate catalysts of MS-4A and MnO2/ALP located in the afterglow area to achieve the synergistic effects on effective fission of chemical bonds of chlorobenzene. It was considered that the gas-chlorobenzene and the chlorobenzene adsorbed on the catalysts were decomposed simultaneously.

  18. Titanium tetrachloride for silver nanoparticle-humic acid composite contaminant removal in coagulation-ultrafiltration hybrid process: floc property and membrane fouling.

    Science.gov (United States)

    Zhao, Yanxia; Sun, Yangyang; Tian, Chang; Gao, Baoyu; Wang, Yan; Shon, Hokyong; Yang, Yanzhao

    2017-01-01

    Titanium-based coagulation is expected to achieve both efficient water purification and sludge recycling. This study is the first attempt to use titanium tetrachloride (TiCl4) for silver nanoparticle (AgNP)-humic acid composite contaminant removal in a coagulation-ultrafiltration (C-UF) process, where characterization of flocs and membrane fouling under varied coagulant dose, initial solution pH, and AgNP concentration conditions are the main contents. Results suggested that the TiCl4 achieved high AgNP removal in the form of silver nanoparticle through adsorption and sweep flocculation and simultaneously exerted additional 68.2 % higher dissolved organic carbon removal than Al2(SO4)3. The TiCl4 produced larger and stronger flocs but with weaker recoverability and less compact degree than did Al2(SO4)3. Floc properties were independent of AgNP concentration except floc fractal dimension, which was negatively correlated with AgNP concentration. The TiCl4 precoagulation caused less membrane fouling within wider pH range than Al2(SO4)3 did in the C-UF process. Incorporation of AgNPs during the TiCl4 pretreatment process facilitated the mitigation of membrane fouling, which was, however, negligibly influenced by AgNP concentration in the case of Al2(SO4)3.

  19. Microbially mediated clinoptilolite regeneration in a multifunctional permeable reactive barrier used to remove ammonium from landfill leachate contamination: laboratory column evaluation.

    Science.gov (United States)

    Nooten, Thomas Van; Diels, Ludo; Bastiaens, Leen

    2010-05-01

    This study focuses on multifunctional permeable reactive barrier (multibarrier) technology, combining microbial degradation and abiotic ion exchange processes for removal of ammonium from landfill leachate contamination. The sequential multibarrier concept relies on the use of a clinoptilolite-filled buffer compartment to ensure a robust ammonium removal in case of temporary insufficient microbial activities. An innovative strategy was developed to allow in situ clinoptilolite regeneration. Laboratory-scale clinoptilolite-filled columns were first saturated with ammonium, using real landfill leachate as well as synthetic leachates as feed media. Other inorganic metal cations, typically present in landfill leachate, had a detrimental influence on the ammonium removal capacity by competing for clinoptilolite exchange sites. On the other hand, the metals had a highly favorable impact on regeneration of the saturated material. Feeding the columns with leachate deprived from ammonium (e.g., by microbial nitrification in an upgradient compartment), resulted in a complete release of the previously sorbed ammonium from the clinoptilolite, due to exchange with metal cations present in the leachate. The released ammonium is then available for microbial consumption in a downgradient compartment. The regeneration process resulted in a slightly increased ammonium exchange capacity afterward. The described strategy throws a new light on sustainable use of sorption materials for in situ groundwater remediation, by avoiding the need for material replacement and the use of external chemical regenerants.

  20. Synthesis of mesoporous magnetic gamma-Fe2O3 and its application to Cr(VI) removal from contaminated water.

    Science.gov (United States)

    Wang, Peng; Lo, Irene M C

    2009-08-01

    In this study, mesoporous magnetic iron-oxide (gamma-Fe(2)O(3)) was synthesized as an adsorbent for Cr(VI) removal. For material synthesis, mesoporous silica (KIT-6) was used as a hard template and to drive iron precursor into KIT-6, a 'greener', affinity based impregnation method was employed, which involved using a nonpolar solvent (xylene) and led to recycling of the solvent. The results of Cr(VI) removal experiments showed that the synthesized mesoporous gamma-Fe(2)O(3) has a Cr(VI) adsorption capacity comparable with 10nm nonporous gamma-Fe(2)O(3) but simultaneously has a much faster separation than 10nm nonporous gamma-Fe(2)O(3) in the presence of an external magnetic field under the same experimental conditions. Cr(VI) adsorption capacity onto the mesoporous gamma-Fe(2)O(3) increased with decreasing solution pH and could be readily regenerated. Therefore, mesoporous gamma-Fe(2)O(3) presents a reusable adsorbent for a fast, convenient, and highly efficient removal of Cr(VI) from contaminated water.

  1. Versatile Cellulose-Based Carbon Aerogel for the Removal of Both Cationic and Anionic Metal Contaminants from Water.

    Science.gov (United States)

    Alatalo, Sara-Maaria; Pileidis, Filoklis; Mäkilä, Ermei; Sevilla, Marta; Repo, Eveliina; Salonen, Jarno; Sillanpää, Mika; Titirici, Maria-Magdalena

    2015-11-25

    Hydrothermal carbonization of cellulose in the presence of the globular protein ovalbumin leads to the formation of nitrogen-doped carbon aerogel with a fibrillar continuous carbon network. The protein plays here a double role: (i) a natural source of nitrogen functionalities (2.1 wt %) and (ii) structural directing agent (S(BET) = 38 m(2)/g). The applicability in wastewater treatment, namely, for heavy metal removal, was examined through adsorption of Cr(VI) and Pb(II) ion solely and in a mixed bicomponent aqueous solutions. This cellulose-based carbogel shows an enhanced ability to remove both Cr(VI) (∼68 mg/g) and Pb(II) (∼240 mg/g) from the targeted solutions in comparison to other carbon materials reported in the literature. The presence of competing ions showed little effect on the adsorption efficiency toward Cr(VI) and Pb(II).

  2. Electrochemically enhanced reduction of hexavalent chromium in contaminated clay: Kinetics, energy consumption, and application of pulse current

    DEFF Research Database (Denmark)

    Sun, Tian Ran; Pamukcu, Sibel; Ottosen, Lisbeth M.;

    2015-01-01

    Electrochemically enhanced reduction of Cr(VI) in clay medium is a technique based on inputting extra energy into the clay to drive the favorable redox reaction. In this study, the reducing reagent Fe(II) was transported into Cr(VI) spiked kaolinite clay by direct current to investigate the depen......Electrochemically enhanced reduction of Cr(VI) in clay medium is a technique based on inputting extra energy into the clay to drive the favorable redox reaction. In this study, the reducing reagent Fe(II) was transported into Cr(VI) spiked kaolinite clay by direct current to investigate......,Fe)(OH)3] precipitates. XRD analysis suggested that the [(Cr,Fe)(OH)3] formed at the clay surface and grew into the pore fluid. SEM-EDX results indicated that the overall Fe(III):Cr(III) ratio of the precipitates was approximately 1.26:1. Application of pulse current decreased the non-productive energy...

  3. Some ozone advanced oxidation processes to improve the biological removal of selected pharmaceutical contaminants from urban wastewater.

    Science.gov (United States)

    Espejo, Azahara; Aguinaco, Almudena; Amat, Ana M; Beltrán, Fernando J

    2014-01-01

    Removal of nine pharmaceutical compounds--acetaminophen (AAF), antipyrine (ANT), caffeine (CAF), carbamazepine (CRB), diclofenac (DCF), hydrochlorothiazide (HCT), ketorolac (KET), metoprolol (MET) and sulfamethoxazole (SMX)-spiked in a primary sedimentation effluent of a municipal wastewater has been studied with sequential aerobic biological and ozone advanced oxidation systems. Combinations of ozone, UVA black light and Fe(III) or Fe3O4 constituted the chemical systems. During the biological treatment (hydraulic residence time, HRT = 24 h), only AAF and CAF were completely eliminated, MET, SMX and HCT reached partial removal rates and the rest of compounds were completely refractory. With any ozone advanced oxidation process applied, the remaining pharmaceuticals disappear in less than 10 min. Fe3O4 or Fe(III) photocatalytic ozonation leads to 35% mineralization compared to 13% reached during ozonation alone after about 30-min reaction. Also, biodegradability of the treated wastewater increased 50% in the biological process plus another 150% after the ozonation processes. Both untreated and treated wastewater was non-toxic for Daphnia magna (D. magna) except when Fe(III) was used in photocatalytic ozonation. In this case, toxicity was likely due to the ferryoxalate formed in the process. Kinetic information on ozone processes reveals that pharmaceuticals at concentrations they have in urban wastewater are mainly removed through free radical oxidation.

  4. Removal of the arsenic from contaminated groundwater with use of the new generation of MicroDrop Aqua system

    DEFF Research Database (Denmark)

    Kowalski, Krzysztof; Søgaard, Erik Gydesen

    2012-01-01

    The results from a new pilot scale plant of the MicroDrop Aqua arsenic removal technology are introduced. The technology is based on the employing of electrochemical iron dissolution and efficient aeration prior to sand filtration. The pilot treatment was used to study effectiveness of iron release...... in an electro-dissolution process that is taking place in an iron generator. It was found that there is a need of some extra time to reach a state of steady iron release and that could not be achieved within a short period of 10-20 minutes. The pilot plant proved to be able to remove arsenic to value below 5μg....../L and it has been shown that the process efficiency depends on the applied current. Moreover, it was found that iron accumulation in the sand filter had a positive effect on the arsenic removal activity and it shall be considered in future tests. The presented method enables efficiently, without chemical...

  5. Measurement of magnetic fields produced by a "magnetic deflector" for the removal of electron contamination in radiotherapy.

    Science.gov (United States)

    Damrongkijudom, N; Oborn, B; Butson, M; Rosenfeld, A

    2006-12-01

    Electron contamination generated from interactions of x-rays with components in a medical linear accelerator's head can increase damage to skin and subcutaneous tissue during radiotherapy through increased dose deposition. Skin and subcutaneous dose from high energy x-rays can be reduced using magnetic fields to sweep the electron contamination away from the radiation treatment field. This work is aimed at investigating the magnetic fields generated by an improved magnetic deflector which utilizes Nd2Fe14B magnets. Magnetic field strengths generated by the deflector have been simulated using Vizimag 3.0 magnetic modelling software. The improved deflector has a more uniform magnetic field strength than its predecessor and is optimised to easily fit on a clinical linear accelerator. Experimental measurements of the magnetic field strengths produced have also been performed for comparison. Results show a relatively good match to Vizimag modelling in the central regions of the deflector. Reductions of skin and subcutaneous dose up to 34% of original values were seen for a 20 x 20 cm2 field at 6MV x-ray energy.

  6. Elastomer Change Out - Justification for minimizing the removal of elastomers in order to prevent cross contamination in a multiproduct facility.

    Science.gov (United States)

    Parks, Michael; O'Dwyer, Niamh; Bollinger, Jeremy; Johnson, Alan; Goss, Brian; Wyman, Ned; Arroyo, Adeyma; Wood, Joseph; Willison-Parry, Derek

    2017-09-19

    The primary objective of any Biopharmaceutical Product Changeover (PCO) program is to employ control strategies before, during, and after the manufacturing process, as well as from the beginning of the lifecycle approach for the equipment and validation, which will minimize the opportunity for cross- contamination when switching between products. Evaluation of the need for an Elastomer Change Out (ECO) should be considered as a segment of an overall changeover assessment. Lifecycle systems (e.g. Preventive Maintenance (PM), Cleanability Coupon Testing, Good Engineering Practices, etc.) and procedures should be in place and data should be generated demonstrating the soft parts do not harbor residues from the previous product campaign(s). The determination of whether or not to replace elastomers/soft parts should be made in the context of all of these systems along with the proper assessment of Risk. By understanding the actual value of ECO in terms of the overall PCO program, and the other systems and procedures that are in place that protect against cross contamination, the need for ECO for every product changeover is not necessary. The purpose of this paper is to review the practice of ECO at product changeover, evaluate the need for an ECO using a risk based approach, and provide rationale for justifying the reduction or elimination of ECO at product changeover. Copyright © 2017, Parenteral Drug Association.

  7. Optimization of Human Corneal Endothelial Cells for Culture: The Removal of Corneal Stromal Fibroblast Contamination Using Magnetic Cell Separation

    Directory of Open Access Journals (Sweden)

    Gary S. L. Peh

    2012-01-01

    Full Text Available The culture of human corneal endothelial cells (CECs is critical for the development of suitable graft alternative on biodegradable material, specifically for endothelial keratoplasty, which can potentially alleviate the global shortage of transplant-grade donor corneas available. However, the propagation of slow proliferative CECs in vitro can be hindered by rapid growing stromal corneal fibroblasts (CSFs that may be coisolated in some cases. The purpose of this study was to evaluate a strategy using magnetic cell separation (MACS technique to deplete the contaminating CSFs from CEC cultures using antifibroblast magnetic microbeads. Separated “labeled” and “flow-through” cell fractions were collected separately, cultured, and morphologically assessed. Cells from the “flow-through” fraction displayed compact polygonal morphology and expressed Na+/K+ATPase indicative of corneal endothelial cells, whilst cells from the “labeled” fraction were mostly elongated and fibroblastic. A separation efficacy of 96.88% was observed. Hence, MACS technique can be useful in the depletion of contaminating CSFs from within a culture of CECs.

  8. Preferential removal and immobilization of stable and radioactive cesium in contaminated fly ash with nanometallic Ca/CaO methanol suspension

    Energy Technology Data Exchange (ETDEWEB)

    Mallampati, Srinivasa Reddy, E-mail: srireddys@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Mitoma, Yoshiharu, E-mail: mitomay@pu-hiroshima.ac.jp [Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho, Shobara City, Hiroshima 727-0023 (Japan); Okuda, Tetsuji [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Sakita, Shogo [Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho, Shobara City, Hiroshima 727-0023 (Japan); Simion, Cristian [Politehnica University of Bucharest, Department of Organic Chemistry, Bucharest 060042 (Romania)

    2014-08-30

    Graphical abstract: Schematic representation of possible mechanisms determining the Cs extraction and immobilization in fly ash during water, methanol or n-MCaS extraction. - Highlights: • nMCaS suspension for cesium extraction and immobilization in fly ash was developed. • Enhanced cesium immobilization was done by nanometallic Ca/CaO methanol suspension. • By SEM analysis the amount of cesium detectable on soil particle surface decreases. • Leachable cesium concentrations reduced, lower than the standard regulatory limit. • nMCaS unique and a highly potential amendment for the remediation of Cs. - Abstract: In this work, the capability of nanometallic Ca/CaO methanol suspension in removing and/or immobilizing stable ({sup 133}Cs) and radioactive cesium species ({sup 134}Cs and {sup 137}Cs) in contaminated fly ash was investigated. After a first methanol and second water washing yielded only 45% of {sup 133}Cs removal. While, after a first methanol washing, the second solvent with nanometallic Ca/CaO methanol suspension yielded simultaneous enhanced removal and immobilization about 99% of {sup 133}Cs. SEM-EDS analysis revealed that the mass percent of detectable {sup 133}Cs on the fly ash surface recorded a 100% decrease. When real radioactive cesium contaminated fly ash (containing an initial 14,040 Bq kg{sup −1134}Cs and {sup 137}Cs cumulated concentration) obtained from burning wastes from Fukushima were reduced to 3583 Bq kg{sup −1} after treatment with nanometallic Ca/CaO methanol suspension. Elution test conducted on the treated fly ash gave 100 Bq L{sup −1} total {sup 134}Cs and {sup 137}Cs concentrations in eluted solution. Furthermore, both ash content and eluted solution concentrations of {sup 134}Cs and {sup 137}Cs were much lower than the Japanese Ministry of the Environment regulatory limit of 8000 Bq kg{sup −1} and 150 Bq L{sup −1} respectively. The results of this study suggest that the nanometallic Ca/CaO methanol suspension is

  9. Solar light induced removal of arsenic from contaminated groundwater: the interplay of solar energy and chemical variables

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.G.; D' Hiriart, J.; Giullitti, J.; Hidalgo, M. del V. [Universidad Nacional de Tucaman (Argentina). Centro de Investigaciones y Transferencia en Quimica Aplicada; Lin, H.; Custo, G.; Litter, M.I. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Unidad de Actividad Quimica; Blesa, M.A. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Unidad de Actividad Quimica; Universidad Nacional de General San Martin (Argentina)

    2004-11-01

    The removal of arsenic by solar oxidation in individual units (SORAS) is currently being explored as a possible economic and simple technology to treat groundwater in Bangladesh and India. Hydroarsenicism affects also large regions of America, especially Argentina, Chile, Mexico and Peru. In this paper, the efficiency of arsenic removal by solar oxidation coupled with precipitation of iron (hydr)oxide, was assessed under various experimental conditions, both on samples of synthetic water and of groundwater of the province of Tucuman (Argentina). The results demonstrate that the underlying chemistry is very complex, and the efficiency is affected often in unpredictable ways by changes in the chemical matrix, or by changes in the operative conditions. Oxides generated from ferrous salts are more efficient than solids formed by hydrolysis of Fe(III); alkalinity contents (bicarbonate) is also important to permit the adequate precipitation. Addition of small amounts of citric acid (lemon juice) is beneficial, but at larger concentrations the effect is negative, probably because of interference in the formation of the solid. The effect of solar irradiation is variable, depending on the other experimental conditions. Although it is possible to remove As partially without solar irradiation under certain special conditions, a procedure versatile enough to cope with waters of different compositions must be based in the use of solar energy. Light plays the role of accelerating the oxidation of As(III) to As(V), and also affects the nature of the solid and, hence, its sorptive properties. The rationale of the effect of light is therefore appreciably more complex than in the case of heterogeneous photocatalysis with TiO{sub 2}. (Author)

  10. Assessment of Phytoextraction Potential of Fenugreek (Trigonellafoenum-graecum L. to Remove Heavy Metals (Pb and Ni from Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Leela Kaur

    2015-02-01

    Full Text Available The objective of the present study was to evaluate the effect of metal mobilizing agents, ethelynediaminetetraacetic acid (EDTA and salicylic acid (SA, on the accumulation and translocation of lead (Pb and nickel (Ni by fenugreek (Trigonellafoenum-graecumL. plants in contaminated soil. EDTA and SA were amended at 100 mM and 1.0 mM respectively. Pb and Ni content were estimated using ICP-OES. Plant samples were prepared for scanning electron microscope (SEM analysis to investigate metals distribution in different tissues (root, stem and leaf of plant. The results showed that EDTA increased Pb and Ni uptake as compared to SA. SEM analysis revealed that in the presence of EDTA, the deposition of Pb particles was predominantly in vascular tissues of the stem and leaf.    

  11. Hot air injection for removal of dense, non-aqueous-phase liquid contaminants from low-permeability soils

    Energy Technology Data Exchange (ETDEWEB)

    Payne, F.C.

    1996-08-01

    The performance of soil vapor extraction systems for the recovery of volatile and semi-volatile organic compounds is potentially enhanced by the injection of heated air to increase soil temperatures. The soil temperature increase is expected to improve soil vapor extraction (SVE) performance by increasing target compound vapor pressures and by increasing soil permeability through drying. The vapor pressure increase due to temperature rise relieves the vapor pressure limit on the feasibility of soil vapor extraction. However, the system still requires an air flow through the soil system to deliver heat and to recover mobilized contaminants. Although the soil permeability can be increased through drying, very low permeability soils and low permeability soils adjacent to high permeability air flow pathways will be treated slowly, if at all. AR thermal enhancement methods face this limitation. Heated air injection offers advantages relative to other thermal techniques, including low capital and operation costs. Heated air injection is at a disadvantage relative to other thermal techniques due to the low heat capacity of air. To be effective, heated air injection requires that higher air flows be established than for steam injection or radio frequency heating. Heated air injection is not economically feasible for the stratified soil system developed as a standard test for this document. This is due to the inability to restrict heated air flow to the clay stratum when a low-resistance air flow pathway is available in the adjoining sand. However, the technology should be especially attractive, both technically and economically, for low-volatile contaminant recovery from relatively homogeneous soil formations. 16 refs., 2 tabs.

  12. A comparative assessment of intensive and extensive wastewater treatment technologies for removing emerging contaminants in small communities.

    Science.gov (United States)

    Matamoros, Víctor; Rodríguez, Yolanda; Albaigés, Joan

    2016-01-01

    Ecosystem pollution due to the lack of or inefficient wastewater treatment coverage in small communities is still a matter of great concern, even in developed countries. This study assesses the seasonal performance of 4 different full-scale wastewater technologies that have been used in small communities (constructed wetland (CW) and a waste stabilization pond (WSP)), all located in north-eastern Spain. The studied compounds belonged to the groups of pharmaceuticals, sunscreen compounds, fragrances, antiseptics, flame retardants, surfactants, pesticides and plasticizers. The 25 ECs occurred in wastewater at concentrations ranging from undetectable to 80 μg L(-1). The average removal efficiency was 42% for the CW, 62% for the AS, 63% for the RBC and 82% for the WSP. All the technologies except the WSP system showed seasonal variability in the removal of ECs. The ecotoxicological assessment study revealed that, whilst all the technologies were capable of decreasing the aquatic risk, only the WSP yielded no risk in both seasons. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Hierarchical porous structured zeolite composite for removal of ionic contaminants from waste streams and effective encapsulation of hazardous waste.

    Science.gov (United States)

    Al-Jubouri, Sama M; Curry, Nicholas A; Holmes, Stuart M

    2016-12-15

    A hierarchical structured composite made from clinoptilolite supported on date stones carbon is synthesized using two techniques. The composites are manufactured by fixing a natural zeolite (clinoptilolite) to the porous surface of date stones carbon or by direct hydrothermal synthesis on to the surface to provide a supported high surface area ion-exchange material for metal ion removal from aqueous streams. The fixing of the clinoptilolite is achieved using sucrose and citric acid as a binder. The composites and pure clinoptilolite were compared to test the efficacy for the removal of Sr(2+) ions from an aqueous phase. The encapsulation of the Sr(2+) using either vitrification or a geo-polymer addition was tested to ensure that the hazardous waste can be made safe for disposal. The hierarchical structured composites were shown to achieve a higher ion exchange capacity per gram of zeolite than the pure clinoptilolite (65mg/g for the pure natural clinoptilolite and 72mg/g for the pure synthesized clinoptilolite) with the synthesized composite (160mg/g) having higher capacity than the natural clinoptilolite composite (95mg/g). The rate at which the equilibria were established followed the same trend showing the composite structure facilitates diffusion to the ion-exchange sites in the zeolite.

  14. Use of chemically activated cotton nut shell carbon for the removal of fluoride contaminated drinking water:Kinetics evaluation☆

    Institute of Scientific and Technical Information of China (English)

    Rajan Mariappan; Raj Vairamuthu; Alagumuthu GanapathY

    2015-01-01

    Chemically activated cotton nut shell carbons (CTNSCs) were prepared by different chemicals and they were used for the removal of fluoride from aqueous solution. Effects of adsorption time, adsorbent dose, pH of the solution, initial concentration of fluoride, and temperature of the solution were studied with equilibrium, ther-modynamics and kinetics of the adsorption process by various CTNSC adsorbents. It showed that the chemical y activated CTNSCs can effectively remove fluoride from the solution. The adsorption equilibrium data correlate well with the Freundlich isotherm model. The adsorption of fluoride by the chemical y activated CTNSC is spon-taneous and endothermic in nature. The pseudo first order, pseudo second order and intra particle diffusion kinetic models were applied to test the experimental data. The pseudo second order kinetic model provided a better correlation of the experimental data in comparison with the pseudo-first-order and intra particle diffusion models. A mechanism of fluoride adsorption associating chemisorption and physisorption processes is presented allowing the discussion of the variations in adsorption behavior between these materials in terms of specific surface area and porosity. These data suggest that chemically activated CTNSCs are promising materials for fluoride sorption.

  15. Production and application of porous membrane for removal of contaminants in treated water - doi: 10.4025/actascitechnol.v34i4.10492

    Directory of Open Access Journals (Sweden)

    Flávia Fernanda Mayumi Susuki

    2012-10-01

    Full Text Available Due to several factors caused by urban and industrial growth worldwide, water supply problems have become increasingly complex, with difficult and costly solutions. The use of membrane filters is one of the newest unit operation options being incorporated into the water and sewage treatment process. This work involves the study of the production of a polymeric asymmetric porous membrane to be used in the removal of possible abiotic or biological contaminants remaining after the post-treatment of drinking water, as well as the assessment of the membrane life span. The phase inversion process was used to produce the membrane, using a polymer solution consisting of polyvinylidene fluoride (PVDF and polymethyl methacrylate (PMMA, and NN-Dimethylformamide as a solvent. KCl salts were incorporated as additive, and a polyester polypropylene sheet was used as support. The membrane was tested in a transverse flow module. The tests demonstrated that the membrane presented an effective barrier to abiotic contaminants, with an average flux of 342 kg h-1 m-2 and life span of 48h,Subcritical water treatment of explosive and heavy metals co-contaminated soil: Removal of the explosive, and immobilization and risk assessment of heavy metals.

    Science.gov (United States)

    Islam, Mohammad Nazrul; Jung, Ho-Young; Park, Jeong-Hun

    2015-11-01

    Co-contamination of explosives and heavy metals (HMs) in soil, particularly army shooting range soil, has received increasing environmental concern due to toxicity and risks to ecological systems. In this study, a subcritical water (SCW) extraction process was used to remediate the explosives-plus-HMs-co-contaminated soil. A quantitative evaluation of explosives in the treated soil, compared with untreated soil, was applied to assess explosive removal. The immobilization of HMs was assessed by toxicity characteristic leaching procedure tests, and by investigating the migration of HMs fractions. The environmental risk of HMs in the soil residue was assessed according to the risk assessment code (RAC) and ecological risk indices (Er and RI). The results indicated that SCW treatment could eliminate the explosives, >99%, during the remediation, while the HM was effectively immobilized. The effect of water temperature on reducing the explosives and the risk of HMs in soil was observed. A marked increase in the non-bioavailable concentration of each HM was observed, and the leaching rate of HMs was decreased by 70-97% after SCW treatment at 250 °C, showing the effective immobilization of HMs. According to the RAC or RI, each tested HM showed no or low risk to the environment after treatment.

  16. In situ removal of carbon contamination from optics in a vacuum ultraviolet and soft X-ray undulator beamline using oxygen activated by zeroth-order synchrotron radiation.

    Science.gov (United States)

    Toyoshima, Akio; Kikuchi, Takashi; Tanaka, Hirokazu; Adachi, Jun Ichi; Mase, Kazuhiko; Amemiya, Kenta

    2012-09-01

    Carbon contamination of optics is a serious issue in all soft X-ray beamlines because it decreases the quality of experimental data, such as near-edge X-ray absorption fine structure, resonant photoemission and resonant soft X-ray emission spectra in the carbon K-edge region. Here an in situ method involving the use of oxygen activated by zeroth-order synchrotron radiation was used to clean the optics in a vacuum ultraviolet and soft X-ray undulator beamline, BL-13A at the Photon Factory in Tsukuba, Japan. The carbon contamination of the optics was removed by exposing them to oxygen at a pressure of 10(-1)-10(-4) Pa for 17-20 h and simultaneously irradiating them with zeroth-order synchrotron radiation. After the cleaning, the decrease in the photon intensity in the carbon K-edge region reduced to 2-5%. The base pressure of the beamline recovered to 10(-7)-10(-8) Pa in one day without baking. The beamline can be used without additional commissioning.

  17. Removal of Uranium and Associated Contaminants from Aqueous Solutions Using Functional Carbon Nanotubes-Sodium Alginate Conjugates

    Directory of Open Access Journals (Sweden)

    Hussein Allaboun

    2016-02-01

    Full Text Available Synthesis of hydrophilic/hydrophobic beads from functional carbon nanotubes (CNTs conjugated with sodium alginate was investigated. Glutaraldehyde was used as a coupling agent and Ca2+ as a crosslinking agent. The formed conjugate comprises two-dimensional sheets of sodium alginate bounded to long tufts of functional CNT tails of micro-size geometry. Detailed characterization of the conjugates was performed using thermogravimetric analysis (TGA and its first derivative (DTG, Fourier transform infrared (FTIR, and scanning electron microscope (SEM techniques. Different ratios of the conjugate were successfully prepared and used as biodegradable environmentally friendly sorbents. Removal of U6+, V3+, Cr3+, Mo3+, Pb2+, Mn2+, Cu2+, Ti4+ and Ni2+ from aqueous solutions using the synthesized biosorbent was experimentally demonstrated. Maximum metal uptake of 53 mg/g was achieved using the % Functional CNTs = 33 sample.

  18. Removal of copper from copper-contaminated river water and aqueous solutions using Methylobacterium extorquens modified Erzurum clayey soil

    Directory of Open Access Journals (Sweden)

    Celebi Neslihan

    2016-12-01

    Full Text Available The objective of this study was to investigate the possibility of using natural and bacteria-modified Erzurum clayey soil with Methylobacterium extorquens as an alternative to high cost commercial adsorbent materials for the removal of copper from aqueous solution. The copper concentrations in the samples of the polluted river water and CuCl2 solutions treated by the natural and bacteria-modified Erzurum clayey soil (ECS have been determined by spectrophotometric method. Firstly, the surface of ECS was modified with M. extorquens and surface functionality was increased. Then, the adsorption of Cu (II from solution phases was studied with respect to varying metal concentration, pH, and temperature and agitation time. The maximum adsorption of Cu (II for natural and bacteria-modified Erzurum clayey soil was observed at pH: 5.0. At different copper concentrations, copper adsorption analysis was performed on 1 g using clay soil or modified clay soil. Maximum adsorption of Cu (II was obtained as 45.7 and 48.1 mg g-1 at initial concentration (50 mg/50 mL and optimal conditions by natural and bacteria-modified clay soil, respectively. The copper concentration was decreased in the substantial amount of the leachates solutions of natural and bacteria-modified clay soil. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of Cu (II ions. The results showed that modified clay soil had a high level of adsorption capacity for copper ion. The various thermodynamic parameters such as ΔG°, ΔH° and ΔS° were analyzed to observe the nature of adsorption. The structural properties of the natural and bacteria-modified-ECS have been characterized by SEM, FTIR and XRD techniques. Consequently, it was concluded that the bacteria-modified clay soil could be successfully used for the removal of the copper ions from the aqueous solutions.

  19. VOC removal from contaminated groundwater through membrane pervaporation. (Ⅱ): 1,1,1-trichloroethane- SDS surfactant solution system

    Institute of Scientific and Technical Information of China (English)

    PENG Ming; Sean LIU

    2003-01-01

    The conventional "pump-and-treat" technology for subsurface remediation of groundwater contaminated with volatile organic compounds(VOCs) such as 1,1,1-trichloroethane(TCA), a common chlorinated organic solvent, has limitation of prohibitively long treatment time due to extremely low