PRTR ion exchange vault water removal

International Nuclear Information System (INIS)

Ham, J.E.

1995-11-01

This report documents the removal of radiologically contaminated water from the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. Approximately 57,000 liters (15,000 gallons) of water had accumulated in the vault due to the absence of a rain cover. The water was removed and the vault inspected for signs of leakage. No evidence of leakage was found. The removal and disposal of the radiologically contaminated water decreased the risk of environmental contamination

Removal of bromates from water

Science.gov (United States)

Barlokova, D.; Ilavsky, J.; Marko, I.; Tkacova, J.

2017-10-01

Bromates are substances that are usually not present in drinking water. They are obtained by ozone disinfection in the presence of bromine ions in water, as an impurity of sodium hypochlorite, respectively. Because of their specific properties, bromates are classified as vary dangers substances, that can cause serious illnesses in humans. There are several technological processes that have been used to the removal of bromates from water at present. In this article, the removal of the bromates from water by the adsorption using various sorbent materials (activated carbon, zeolite, Klinopur-Mn, Bayoxide E33, GEH, Read-As and Activated alumina) are presented. The effectiveness of selected sorbent materials in the removal of bromates from drinking water moves in the interval from 10 to 40%. Based on laboratory results, the zeolite can be used to reduce the concentration of bromates in water.

Computational study of ibuprofen removal from water by adsorption in realistic activated carbons.

Science.gov (United States)

Bahamon, Daniel; Carro, Leticia; Guri, Sonia; Vega, Lourdes F

2017-07-15

Molecular simulations using the Grand Canonical Monte Carlo (GCMC) method have been performed in order to obtain physical insights on how the interaction between ibuprofen (IBP) and activated carbons (ACs) in aqueous mixtures affects IBP removal from water by ACs. A nanoporous carbon model based on units of polyaromatic molecules with different number of rings, defects and polar-oxygenated sites is described. Individual effects of factors such as porous features and chemical heterogeneities in the adsorbents are investigated and quantified. Results are in good agreement with experimental adsorption data, highlightening the ability of GCMC simulation to describe the macroscopic adsorption performance in drug removal applications, while also providing additional insights into the IBP/water adsorption mechanism. The simulation results allow finding the optimal type of activated carbon material for separating this pollutant in water treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

49 CFR 193.2173 - Water removal.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Water removal. 193.2173 Section 193.2173...: FEDERAL SAFETY STANDARDS Design Impoundment Design and Capacity § 193.2173 Water removal. (a) Impoundment areas must be constructed such that all areas drain completely to prevent water collection. Drainage...

Removal of oil from water by bentonite

International Nuclear Information System (INIS)

Moazed, H.; Viraraghavan, T.

1999-01-01

Many materials, included activated carbon, peat, coal, fiberglass, polypropylene, organoclay and bentonite have been used for removing oils and grease from water. However, bentonite has been used only rarely for this purpose. In this study Na-bentonite was used to remove oil from oil-in-water emulsions of various kinds such as standard mineral oil, cutting oils, refinery effluent and produced water from production wells at Estevan, Saskatchewan. Removal efficiencies obtained were 85 to 96 per cent for cutting oils, 84 to 86 per cent for produced water and 54 to 87 per cent for refinery effluent. Bentonite proved to be more effective in the removal of oil from oil-in-water emulsions than from actual waste waters; up to 96 percent from oil-in-water emulsions to only 87 per cent from actual waste water. The percentage of oil removed was found to be a function of the amount of bentonite added and the adsorption time up to the equilibrium time. Result also showed that the Langmuir, Freundlich and BET isotherms are well suited to describe the adsorption of oil by bentonite from the various oily waters employed in this study. 15 refs

Towards ligand docking including explicit interface water molecules.

Directory of Open Access Journals (Sweden)

Gordon Lemmon

Full Text Available Small molecule docking predicts the interaction of a small molecule ligand with a protein at atomic-detail accuracy including position and conformation the ligand but also conformational changes of the protein upon ligand binding. While successful in the majority of cases, docking algorithms including RosettaLigand fail in some cases to predict the correct protein/ligand complex structure. In this study we show that simultaneous docking of explicit interface water molecules greatly improves Rosetta's ability to distinguish correct from incorrect ligand poses. This result holds true for both protein-centric water docking wherein waters are located relative to the protein binding site and ligand-centric water docking wherein waters move with the ligand during docking. Protein-centric docking is used to model 99 HIV-1 protease/protease inhibitor structures. We find protease inhibitor placement improving at a ratio of 9:1 when one critical interface water molecule is included in the docking simulation. Ligand-centric docking is applied to 341 structures from the CSAR benchmark of diverse protein/ligand complexes [1]. Across this diverse dataset we see up to 56% recovery of failed docking studies, when waters are included in the docking simulation.

Molecular dynamics study of water molecule diffusion in oil-paper insulation materials

International Nuclear Information System (INIS)

Liao Ruijin; Zhu Mengzhao; Yang Lijun; Zhou Xin; Gong Chunyan

2011-01-01

Moisture is an important factor that influences the safe operation of transformers. In this study, molecular dynamics was employed to investigate the diffusion behavior of water molecules in the oil-paper insulation materials of transformers. Two oil-cellulose models were built. In the first model, water molecules were initially distributed in oil, and in the second model, water molecules were distributed in cellulose. The non-bonding energies of interaction between water molecules and oil, and between water molecules and cellulose, were calculated by the Dreiding force field. The interaction energy was found to play a dominant role in influencing the equilibrium distribution of water molecules. The radial direction functions of water molecules toward oil and cellulose indicate that the hydrogen bonds between water molecules and cellulose are sufficiently strong to withstand the operating temperature of the transformer. Mean-square displacement analysis of water molecules diffusion suggests that water molecules initially distributed in oil showed anisotropic diffusion; they tended to diffuse toward cellulose. Water molecules initially distributed in cellulose diffused isotropically. This study provides a theoretical contribution for improvements in online monitoring of water in transformers, and for subsequent research on new insulation materials.

Molecular dynamics study of water molecule diffusion in oil-paper insulation materials

Energy Technology Data Exchange (ETDEWEB)

Liao Ruijin [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China); Zhu Mengzhao, E-mail: xiaozhupost@163.co [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China); Yang Lijun; Zhou Xin; Gong Chunyan [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China)

2011-03-01

Moisture is an important factor that influences the safe operation of transformers. In this study, molecular dynamics was employed to investigate the diffusion behavior of water molecules in the oil-paper insulation materials of transformers. Two oil-cellulose models were built. In the first model, water molecules were initially distributed in oil, and in the second model, water molecules were distributed in cellulose. The non-bonding energies of interaction between water molecules and oil, and between water molecules and cellulose, were calculated by the Dreiding force field. The interaction energy was found to play a dominant role in influencing the equilibrium distribution of water molecules. The radial direction functions of water molecules toward oil and cellulose indicate that the hydrogen bonds between water molecules and cellulose are sufficiently strong to withstand the operating temperature of the transformer. Mean-square displacement analysis of water molecules diffusion suggests that water molecules initially distributed in oil showed anisotropic diffusion; they tended to diffuse toward cellulose. Water molecules initially distributed in cellulose diffused isotropically. This study provides a theoretical contribution for improvements in online monitoring of water in transformers, and for subsequent research on new insulation materials.

REMOVAL OF ARSENIC FROM DRINKING WATER SUPPLIES BY IRON REMOVAL PROCESS

Science.gov (United States)

This design manual is an in-depth presentation of the steps required to design and operate a water treatment plant for removal of arsenic in the As (V) form from drinking water using an iron removal process. The manual also discusses the capital and operating costs including many...

Water Distribution and Removal Model

International Nuclear Information System (INIS)

Y. Deng; N. Chipman; E.L. Hardin

2005-01-01

The design of the Yucca Mountain high level radioactive waste repository depends on the performance of the engineered barrier system (EBS). To support the total system performance assessment (TSPA), the Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is developed to describe the thermal, mechanical, chemical, hydrological, biological, and radionuclide transport processes within the emplacement drifts, which includes the following major analysis/model reports (AMRs): (1) EBS Water Distribution and Removal (WD and R) Model; (2) EBS Physical and Chemical Environment (P and CE) Model; (3) EBS Radionuclide Transport (EBS RNT) Model; and (4) EBS Multiscale Thermohydrologic (TH) Model. Technical information, including data, analyses, models, software, and supporting documents will be provided to defend the applicability of these models for their intended purpose of evaluating the postclosure performance of the Yucca Mountain repository system. The WD and R model ARM is important to the site recommendation. Water distribution and removal represents one component of the overall EBS. Under some conditions, liquid water will seep into emplacement drifts through fractures in the host rock and move generally downward, potentially contacting waste packages. After waste packages are breached by corrosion, some of this seepage water will contact the waste, dissolve or suspend radionuclides, and ultimately carry radionuclides through the EBS to the near-field host rock. Lateral diversion of liquid water within the drift will occur at the inner drift surface, and more significantly from the operation of engineered structures such as drip shields and the outer surface of waste packages. If most of the seepage flux can be diverted laterally and removed from the drifts before contacting the wastes, the release of radionuclides from the EBS can be controlled, resulting in a proportional reduction in dose release at the accessible environment

Water Distribution and Removal Model

Energy Technology Data Exchange (ETDEWEB)

Y. Deng; N. Chipman; E.L. Hardin

2005-08-26

The design of the Yucca Mountain high level radioactive waste repository depends on the performance of the engineered barrier system (EBS). To support the total system performance assessment (TSPA), the Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is developed to describe the thermal, mechanical, chemical, hydrological, biological, and radionuclide transport processes within the emplacement drifts, which includes the following major analysis/model reports (AMRs): (1) EBS Water Distribution and Removal (WD&R) Model; (2) EBS Physical and Chemical Environment (P&CE) Model; (3) EBS Radionuclide Transport (EBS RNT) Model; and (4) EBS Multiscale Thermohydrologic (TH) Model. Technical information, including data, analyses, models, software, and supporting documents will be provided to defend the applicability of these models for their intended purpose of evaluating the postclosure performance of the Yucca Mountain repository system. The WD&R model ARM is important to the site recommendation. Water distribution and removal represents one component of the overall EBS. Under some conditions, liquid water will seep into emplacement drifts through fractures in the host rock and move generally downward, potentially contacting waste packages. After waste packages are breached by corrosion, some of this seepage water will contact the waste, dissolve or suspend radionuclides, and ultimately carry radionuclides through the EBS to the near-field host rock. Lateral diversion of liquid water within the drift will occur at the inner drift surface, and more significantly from the operation of engineered structures such as drip shields and the outer surface of waste packages. If most of the seepage flux can be diverted laterally and removed from the drifts before contacting the wastes, the release of radionuclides from the EBS can be controlled, resulting in a proportional reduction in dose release at the accessible environment. The purposes

Boron removal from geothermal waters by electrocoagulation

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey); Yilmaz, M. Tolga; Paluluoglu, Cihan [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)

2008-05-01

Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm{sup 2}, but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.

Boron removal from geothermal waters by electrocoagulation

International Nuclear Information System (INIS)

Yilmaz, A. Erdem; Boncukcuoglu, Recep; Kocakerim, M. Muhtar; Yilmaz, M. Tolga; Paluluoglu, Cihan

2008-01-01

Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm 2 , but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%

On the Several Molecules and Nanostructures of Water

Directory of Open Access Journals (Sweden)

Cynthia Kolb Whitney

2012-01-01

Full Text Available This paper investigates the water molecule from a variety of viewpoints. Water can involve different isotopes of Hydrogen and Oxygen, it can form differently shaped isomer molecules, and, when frozen, it occupies space differently than most other substances do. The tool for conducting the investigation of all this is called ‘Algebraic Chemistry’. This tool is a quantitative model for predicting the energy budget for all sorts of changes between different ionization states of atoms that are involved in chemical reactions and in changes of physical state. The model is based on consistent patterns seen in empirical data about ionization potentials, together with rational scaling laws that can interpolate and extrapolate for situations where no data are available. The results of the investigation of the water molecule include comments, both positive and negative, about technologies involving heavy water, poly water, Brown’s gas, and cold fusion.

Methods of removing uranium from drinking water. 1. A literature survey. 2. Present municipal water treatment and potential removal methods

International Nuclear Information System (INIS)

Drury, J.S.; Michelson, D.; Ensminger, J.T.; Lee, S.Y.; White, S.K.

1982-12-01

Literature was searched for methods of removing uranium from drinking water. U.S. manufacturers and users of water-treatment equipment and products were also contacted regarding methods of removing uranium from potable water. Based on the results of these surveys, it was recommended that untreated, partially treated, and finished water samples from municipal water-treatment facilities be analyzed to determine the extent of removal of uranium by presently used procedures, and that additional laboratory studies be performed to determine what changes are needed to maximize the effectiveness of treatments that are already in use in existing water-treatment plants

Nitrate Removal from Ground Water: A Review

Directory of Open Access Journals (Sweden)

Archna

2012-01-01

Full Text Available Nitrate contamination of ground water resources has increased in Asia, Europe, United States, and various other parts of the world. This trend has raised concern as nitrates cause methemoglobinemia and cancer. Several treatment processes can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that biological denitrification is more acceptable for nitrate removal than reverse osmosis and ion exchange. This paper reviews the developments in the field of nitrate removal processes which can be effectively used for denitrifying ground water as well as industrial water.

Comparison of biological activated carbon (BAC) and membrane bioreactor (MBR) for pollutants removal in drinking water treatment.

Science.gov (United States)

Tian, J Y; Chen, Z L; Liang, H; Li, X; Wang, Z Z; Li, G B

2009-01-01

Biological activated carbon (BAC) and membrane bioreactor (MBR) were systematically compared for the drinking water treatment from slightly polluted raw water under the same hydraulic retention time (HRT) of 0.5 h. MBR exhibited excellent turbidity removal capacity due to the separation of the membrane; while only 60% of influent turbidity was intercepted by BAC. Perfect nitrification was achieved by MBR with the 89% reduction in ammonia; by contrast, BAC only eliminated a moderate amount of influent ammonia (by 54.5%). However, BAC was able to remove more dissolved organic matter (DOM, especially for organic molecules of 3,000 approximately 500 Daltons) and corresponding disinfection by-product formation potential (DBPFP) in raw water than MBR. Unfortunately, particulate organic matter (POM) was detected in the BAC effluent. On the other hand, BAC and MBR displayed essentially the same capacity for biodegradable organic matter (BOM) removal. Fractionation of DOM showed that the removal efficiencies of hydrophobic neutrals, hydrophobic acids, weakly hydrophobic acids and hydrophilic organic matter through BAC treatment were 11.7%, 8.8%, 13.9% and 4.8% higher than that through MBR; while MBR achieved 13.8% higher hydrophobic bases removal as compared with BAC.

Tar removal from biosyngas in the biomass gasification process. (Liquid + liquid) equilibrium {water + solvent (paraxylene and methyl hexadecanoate) + model molecules of tar (benzene, toluene, phenol)}

International Nuclear Information System (INIS)

Bassil, Georgio; Mokbel, Ilham; Abou Naccoul, Ramy; Stephan, Juliette; Jose, Jacques; Goutaudier, Christelle

2012-01-01

Highlights: ► (Liquid + liquid) equilibria at atmospheric pressure. ► Solubility of benzene (or toluene or phenol) in paraxylene at (303 to 343) K. ► Solubility of benzene (or toluene or phenol) in methyl palmitate or methyl hexadecanoate at (303 to 343) K. ► Correlation of LLE using NRTL model. - Abstract: Tar is generated in the process by the condensation of the gas resulting from biomass gasification. The objective of this work is a contribution to the database on thermodynamic quantity which will be useful at the operation of tar removal from aqueous medium. With this aim, (liquid + liquid) equilibrium of {water + solvent (paraxylene and methyl hexadecanoate) + model molecules of tar (benzene, toluene, phenol)} was studied at temperatures (303.2, 323.2, and 343.2) K. The data obtained were correlated with the non-random two-liquid (NRTL) model.

Removal of Strontium from Drinking Water by Conventional ...

Science.gov (United States)

The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. There is very little data available on strontium removal from drinking water. As a result, there is an immediate need to perform treatment studies. The objective of this work is to evaluate the effectiveness of conventional and lime-soda ash softening treatments to remove strontium from surface and ground waters. Conventional drinking water treatment with aluminum and iron coagulants were able to achieve 12% and 5.9% strontium removal at best, while lime softening removed as much as 78% from natural strontium-containing ground water. Systematic fundamental experiments showed that strontium removal during the lime-soda ash softening was related to pH, calcium concentration and dissolved inorganic carbon concentration. Final strontium concentration was also directly associated with initial strontium concentration. Precipitated solids showed well-formed crystals or agglomerates of mixed solids, two polymorphs of calcium carbonate (vaterite and calcite), and strontianite, depending on initial water quality conditions. X-ray diffraction analysis suggested that strontium likely replaced calcium inside the crystal lattice and was likely mainly responsible for removal during lime softening. To inform the public.

Role of water in the tribochemical removal of bare silicon

Energy Technology Data Exchange (ETDEWEB)

Chen, Cheng; Xiao, Chen [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Xiaodong [Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Peng; Chen, Lei; Qi, Yaqiong [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Qian, Linmao, E-mail: linmao@swjtu.edu.cn [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

2016-12-30

Highlights: • The wear of bare silicon against SiO{sub 2} micro-spherical tip is a tribochemical process with participation of water. • The water amount at Si/SiO{sub 2} interface plays a significant role on the wear of bare silicon. • The role of water relies on the hydroxylation by auto-ionized OH{sup −}, the hydrolysis of H{sub 2}O molecules, and the dissolution of SiO{sub m}H{sub n} in water. - Abstract: Nanowear tests of bare silicon against a SiO{sub 2} microsphere were conducted in air (relative humidity [RH] = 0%–89%) and water using an atomic force microscope. Experimental results revealed that the water played an important role in the tribochemical wear of the bare silicon. A hillock-like wear trace with a height of 0.7 nm was generated on the bare silicon surface in dry air. As the RH increased, the wear depth increased and reached the maximum level in water. Analysis of frictional dissipated energy suggested that the wear of the bare silicon was not dominated by mechanical interactions. High-resolution transmission electron microscopy detection demonstrated that the silicon atoms and crystal lattice underneath the worn area maintained integral perfectly and thus further confirmed the tribochemical wear mechanism of the bare silicon. Finally, the role of water in the tribochemical wear of the bare silicon may be explained by the following three aspects: the hydroxylation by hydroxyl ions auto-ionized in water, the hydrolytic reaction of water molecules, and the dissolution of the tribochemical product SiO{sub m}H{sub n} in liquid water. With increasing RH, a greater water amount would adsorb to the Si/SiO{sub 2} interface and induce a more serious tribochemical wear on the bare silicon surface. The results of this paper may provide further insight into the tribochemical removal mechanism of bare monocrystalline silicon and furnish the wider reaction cognition for chemical mechanical polishing.

Trace-level mercury removal from surface water

International Nuclear Information System (INIS)

Klasson, K.T.; Bostick, D.T.

1998-01-01

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water

Zeolites for nitrosamine and pharmaceutical removal from demineralised and surface water: Mechanisms and efficacy

KAUST Repository

De Ridder, David J.

2012-03-01

Zeolites with a high Si/Al ratio can be used as selective adsorbents in water treatment, targeting organic micropollutants which are removed poorly with activated carbon. Due to size exclusion, many Natural Organic Matter (NOM) components cannot access the pores, thus limiting adsorption competition between organic micropollutant and NOM. Furthermore, zeolite channel diameters are close to molecule diameters, which results in strong van der Waals interaction. MOR200 and ZSM5, the two most hydrophobic zeolites, showed the highest removal of neutral nitrosamines in demineralised water, with higher efficacy than activated carbon. DAY and MOR30, which were relatively hydrophilic zeolites, did not show appreciable removal of any of the nitrosamines. When nitrosamines were adsorbed from surface water, there was no influence of competition with, or pore blockage by, NOM components on nitrosamine removal for ZSM5 zeolite, in contrast to activated carbon. Repulsion of negatively charged pharmaceuticals was significant for ZSM5, which had a Si/Al ratio of 80. MOR200 had a Si/Al ratio of 200, indicating a lower Al content than ZSM5 and, as such, a lower negative surface charge. Charge effects were not observed for MOR200. A relationship was found between the Stokes diameter of the pharmaceuticals and nitrosamines, and their removal by ZSM5 and MOR200, indicating that a "close fit" adsorption mechanism is more likely than hydrophobic interaction in these zeolites. Due to their selective nature, adsorption on zeolites should only be considered as an additional treatment step to existing processes, dedicated for the removal of specific organic micropollutants. Less specific treatment techniques, such as activated carbon filtration, are still required to ensure a broad barrier for organic micropollutants in water treatment. © 2012 Elsevier B.V. All rights reserved.

Radium removal from Australian spa waters

International Nuclear Information System (INIS)

Dickson, B.L.; Meakins, R.L.; Bland, C.J.

1982-01-01

The dissolved radium content of some mineral spring waters in Victoria and Queensland has been found to exceed the maximum permissible concentration in drinking water. Activities in excess of 40 pCi/1 were measured in some bottles. Studies revealed that the dissolved radium content decreased markedly if the spring water was aerated and filtered prior to bottling. The sediment removed contained ferric hydroxide which is a natural scavenging agent for radium. The formation of such sediments in storage tanks and their removal prior to bottling may create a possible radiation hazard

Water removal from a dry barrier cover system

International Nuclear Information System (INIS)

Stormont, J.C.; Ankeny, M.D.; Tansey, M.K.

1994-01-01

The results of the numerical simulations reveal that horizontal air flow through the coarse with reasonable pressure gradients can remove large quantities of water from the cover system. Initially, the water removal from the cover system is dominated by the evaporation and advection of water vapor out of the coarse layer. Once the coarse layer is dry, removal of water by evaporation near the fine/coarse layer interface reduces the local water content and water potential, and water moves toward the fine-coarse layer interface and becomes available for evaporation. This result is important in that it suggests the fine layer water content may be moderated by air flow in the coarse layer. Incorporating diffusion of water vapor from the fine layer into the coarse layer substantially increases the water movement out of the fine layer

The Effect of Water Chemistry on the Removal of Arsenic from Drinking Water During Iron Removal Treatment

Science.gov (United States)

This research investigates the effects of water chemistry, oxidant type and concentration on the removal of iron and arsenic from drinking water. The research will be conducted using one of the National Risk Management Research Laboratory’s Water Supply and Water Resources Divisi...

Autodissociation of a water molecule in liquid water

Energy Technology Data Exchange (ETDEWEB)

Geissler, Phillip L.; Dellago, Christoph; Chandler, David; Hutter, Jurg; Parrinello, Michele

2000-04-01

The dissociation of a water molecule in liquid water is the fundamental event in acid-base chemistry, determining the pH of water.Because the microscopic dynamics of this autodissociation are difficult to probe, both by experiment and by computer simulation, its mechanism has been unknown. Here we report several autodissociation trajectories generated by ab initio molecular dynamics [1]. These trajectories, which were harvested using transition path sampling [2-4], reveal the mechanism for the first time. Rare fluctuations in solvation energies destabilize an oxygen-hydrogen bond. Through the transfer of one or more protons along a hydrogen bond.

Rapid and accurate prediction and scoring of water molecules in protein binding sites.

Directory of Open Access Journals (Sweden)

Gregory A Ross

Full Text Available Water plays a critical role in ligand-protein interactions. However, it is still challenging to predict accurately not only where water molecules prefer to bind, but also which of those water molecules might be displaceable. The latter is often seen as a route to optimizing affinity of potential drug candidates. Using a protocol we call WaterDock, we show that the freely available AutoDock Vina tool can be used to predict accurately the binding sites of water molecules. WaterDock was validated using data from X-ray crystallography, neutron diffraction and molecular dynamics simulations and correctly predicted 97% of the water molecules in the test set. In addition, we combined data-mining, heuristic and machine learning techniques to develop probabilistic water molecule classifiers. When applied to WaterDock predictions in the Astex Diverse Set of protein ligand complexes, we could identify whether a water molecule was conserved or displaced to an accuracy of 75%. A second model predicted whether water molecules were displaced by polar groups or by non-polar groups to an accuracy of 80%. These results should prove useful for anyone wishing to undertake rational design of new compounds where the displacement of water molecules is being considered as a route to improved affinity.

Removal of antibiotics from surface and distilled water in conventional water treatment processes

Science.gov (United States)

Adams, C.; Wang, Y.; Loftin, K.; Meyer, M.

2002-01-01

Conventional drinking water treatment processes were evaluated under typical water treatment plant conditions to determine their effectiveness in the removal of seven common antibiotics: carbadox, sulfachlorpyridazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfathiazole, and trimethoprim. Experiments were conducted using synthetic solutions prepared by spiking both distilled/ deionized water and Missouri River water with the studied compounds. Sorption on Calgon WPH powdered activated carbon, reverse osmosis, and oxidation with chlorine and ozone under typical plant conditions were all shown to be effective in removing the studied antibiotics. Conversely, coagulation/flocculation/sedimentation with alum and iron salts, excess lime/soda ash softening, ultraviolet irradiation at disinfection dosages, and ion exchange were all relatively ineffective methods of antibiotic removal. This study shows that the studied antibiotics could be effectively removed using processes already in use many water treatment plants. Additional work is needed on by-product formation and the removal of other classes of antibiotics.

Removing water from gels

International Nuclear Information System (INIS)

Lane, E.S.; Winter, J.A.

1982-01-01

Water is removed from a gel material by contacting the gel material with an organic liquid and contacting the organic liquid with a gas such that water is taken up by the gas. The invention, in one embodiment, may be used to dry gel materials whilst maintaining an open porous network therein. In one example, the invention is applied to gel precipitated spheres containing uranium and plutonium. (author)

The role of water molecules in computational drug design.

Science.gov (United States)

de Beer, Stephanie B A; Vermeulen, Nico P E; Oostenbrink, Chris

2010-01-01

Although water molecules are small and only consist of two different atom types, they play various roles in cellular systems. This review discusses their influence on the binding process between biomacromolecular targets and small molecule ligands and how this influence can be modeled in computational drug design approaches. Both the structure and the thermodynamics of active site waters will be discussed as these influence the binding process significantly. Structurally conserved waters cannot always be determined experimentally and if observed, it is not clear if they will be replaced upon ligand binding, even if sufficient space is available. Methods to predict the presence of water in protein-ligand complexes will be reviewed. Subsequently, we will discuss methods to include water in computational drug research. Either as an additional factor in automated docking experiments, or explicitly in detailed molecular dynamics simulations, the effect of water on the quality of the simulations is significant, but not easily predicted. The most detailed calculations involve estimates of the free energy contribution of water molecules to protein-ligand complexes. These calculations are computationally demanding, but give insight in the versatility and importance of water in ligand binding.

Theoretical investigation of the ultrafast dissociation of core-ionized water and uracil molecules immersed in liquid water

Energy Technology Data Exchange (ETDEWEB)

Stia, C.R.; Fojon, O.A. [Instituto de Fisica Rosario - CONICET-Universidad Nacional de Rosario, Rosario (Argentina); Gaigeot, M.P. [Laboratoire Analyse et Modelisation pour la Biologie et l' Environnement, LAMBE, UMR-CNRS 8587, Universite d' Evry-Val-d' Essonne, 91 - Evry (France); Institut Universitaire de France, 75 - Paris (France); Vuilleumier, R. [Departement de chimie, Ecole Normale Superieure, 75 - Paris (France); Herve du Penhoat, M.A.; Politis, M.F. [Institut de Mineralogie et de Physique des Milieux Condenses, IMPMC, UMR-CNRS 7590, Universite Pierre et Marie Curie, 75 - Paris (France)

2010-10-15

We present a series of ab initio density functional based calculations of the fragmentation dynamics of core-ionized biomolecules. The computations are performed for pure liquid water, aqueous and isolated Uracil. Core ionization is described by replacing the 1s{sup 2} pseudopotential of one atom of the target molecule (C, N or O) with a pseudopotential for a 1s{sup 1} core-hole state. Our results predict that the dissociation of core-ionized water molecules may be reached during the lifetime of inner-shell vacancy (less than 10 fs), leading to OH bond breakage as a primary outcome. We also observe a second fragmentation channel in which total Coulomb explosion of the ionized water molecule occurs. Fragmentation pathways are found similar for pure water or when the water molecule is in the primary hydration shell of the uracil molecule. In the latter case, the proton may be transferred towards the uracil oxygen atoms. When the core hole is located on the uracil molecule, ultrafast dissociation is only observed in the aqueous environment and for nitrogen-K vacancies, resulting in proton transfers towards the hydrogen-bonded water molecule. (authors)

Removal of radium from drinking water

International Nuclear Information System (INIS)

Clifford, D.A.

1990-01-01

The traditional, proven process for radium removal are sodium ion exchange softening, lime softening, and reverse osmosis. The newer, radium-specific column processes include adsorption onto the Dow RSC and BaSO 4 -impregnated alumina. The most promising new radium-specific treatment process for large-scale use is adsorption onto preformed manganese dioxide followed by multimedia or diatomaceous earth filtration The disposal of radium-contaminated wastewaters and sludges from processes under consideration will be a major factor in process selection. The processes of choice for municipal water supply treatment to remove radium are sodium ion exchange softening, lime softening, manganese dioxide adsorption-filtration, and selective adsorption onto the Dow RSC or BaSO 4 -impregnated alumina. Where the water is brackish, reverse osmosis hyperfiltration should also be considered. The radium removal process of choice for whole-house or point-of-entry treatment is sodium ion exchange softening. For point-of-use radium removal, a standard reverse osmosis system including cartridge filtration, activated carbon adsorption, and reverse osmosis hyperfiltration is recommended. Although no cost estimates have been made, the relative costs from most expensive to least expansive, for radium removal in small community water supplies are reverse osmosis, sodium ion exchange softening, lime soda softening, manganese dioxide adsorption-filtration, and the radium-selective adsorbents. 34 refs., 7 figs., 2 tabs

Present municipal water treatment and potential removal methods

International Nuclear Information System (INIS)

Lee, S.Y.; White, S.K.; Bondietti, E.A.

1982-01-01

Uranium analyses of raw water, intermediate stage, and treated water samples from 20 municipal water treatment plants indicated that the present treatment practices were not effective in removing uranium from raw waters when the influent concentration was in the range of 0.1 to 16 μg/L uranium. Laboratory batch tests revealed that the water softening and coagulant chemicals commonly used were able to remove more than 90% of the dissolved uranium ( < 100 μg/L) in waters if an optimum pH and dosage were provided. Absorbents, titanium oxide and activated charcoal, were also effective in uranium removal under specific conditions. Strong base anion exchange resin was the most efficient uranium adsorbent, and an anion exchange column is a recommended option for the treatment of private well waters containing uranium at higher than desirable levels

Uranium speciation and removal from well water

International Nuclear Information System (INIS)

Ayaz, B.; DeVol, T.; Navratil, J.D.

2001-01-01

The purpose of this work was to determine the form of uranium present in the well water and to test the effectiveness of common household treatment devices to remove uranium and radium. Batch tests with activated carbon, iron powder, anion exchange resin and cation exchange resin were used to characterize the form of uranium in the drinking water. In the tests, water and the separation materials were first equilibrated, filtered and then analyzed by alpha spectrometry. The results of the batch tests showed that it is possible to remove greater than 90% of the uranium and radium in the drinking water by using any of the sorbents listed above. Simple filtration with 0.1 μm had little to no impact on uranium removal. Results of tests using household treatment devices will also be presented. (authors)

Quantum Behavior of Water Molecules Confined to Nanocavities in Gemstones.

Science.gov (United States)

Gorshunov, Boris P; Zhukova, Elena S; Torgashev, Victor I; Lebedev, Vladimir V; Shakurov, Gil'man S; Kremer, Reinhard K; Pestrjakov, Efim V; Thomas, Victor G; Fursenko, Dimitry A; Dressel, Martin

2013-06-20

When water is confined to nanocavities, its quantum mechanical behavior can be revealed by terahertz spectroscopy. We place H2O molecules in the nanopores of a beryl crystal lattice and observe a rich and highly anisotropic set of absorption lines in the terahertz spectral range. Two bands can be identified, which originate from translational and librational motions of the water molecule isolated within the cage; they correspond to the analogous broad bands in liquid water and ice. In the present case of well-defined and highly symmetric nanocavities, the observed fine structure can be explained by macroscopic tunneling of the H2O molecules within a six-fold potential caused by the interaction of the molecule with the cavity walls.

Virus removal efficiency of Cambodian ceramic pot water purifiers.

Science.gov (United States)

Salsali, Hamidreza; McBean, Edward; Brunsting, Joseph

2011-06-01

Virus removal efficiency is described for three types of silver-impregnated, ceramic water filters (CWFs) produced in Cambodia. The tests were completed using freshly scrubbed filters and de-ionized (DI) water as an evaluation of the removal efficiency of the virus in isolation with no other interacting water quality variables. Removal efficiencies between 0.21 and 0.45 log are evidenced, which is significantly lower than results obtained in testing of similar filters by other investigators utilizing surface or rain water and a less frequent cleaning regime. Other experiments generally found virus removal efficiencies greater than 1.0 log. This difference may be because of the association of viruses with suspended solids, and subsequent removal of these solids during filtration. Variability in virus removal efficiencies between pots of the same manufacturer, and observed flow rates outside the manufacturer's specifications, suggest tighter quality control and consistency may be needed during production.

Fluoride Removal from Water by Reverse Osmosis Membrane

Directory of Open Access Journals (Sweden)

Sara Namavar

2013-09-01

Full Text Available As fluoride concentration in drinking water is one of the effective parameters in human health, finding the way to remove excess amount of fluoride from drinking water is very important in water supply projects. Today, with developing in technology and finding new methods, the use of membrane technology for producing fresh water get improved. In this study the efficiency of reverse osmosis method to remove fluoride from water was investigated. Initial concentration of fluoride, sulfate and electrical conductivity in feed water and the effect of associated cation with fluoride ion were studied. All tests adapted from “Standard Methods for Examination of Water and Wastewater”. Determination of fluoride concentration was done according the standard SPANDS method by using a spectrophotometer DR/5000. Obtain results show that with increasing in concentration of fluoride and sulfate and electrical conductivity in feed water the efficiency of RO membrane to remove fluoride reduced. In addition, this efficiency for CaF2 was higher than NaF.

Density, distribution, and orientation of water molecules inside and outside carbon nanotubes.

Science.gov (United States)

Thomas, J A; McGaughey, A J H

2008-02-28

The behavior of water molecules inside and outside 1.1, 2.8, 6.9, and 10.4 nm diameter armchair carbon nanotubes (CNTs) is predicted using molecular dynamics simulations. The effects of CNT diameter on mass density, molecular distribution, and molecular orientation are identified for both the confined and unconfined fluids. Within 1 nm of the CNT surface, unconfined water molecules assume a spatially varying density profile. The molecules distribute nonuniformly around the carbon surface and have preferred orientations. The behavior of the unconfined water molecules is invariant with CNT diameter. The behavior of the confined water, however, can be correlated to tube diameter. Inside the 10.4 nm CNT, the molecular behavior is indistinguishable from that of the unconfined fluid. Within the smaller CNTs, surface curvature effects reduce the equilibrium water density and force water molecules away from the surface. This effect changes both the molecular distribution and preferred molecular orientations.

Arsenic removal in drinking water by reverse osmosis

OpenAIRE

Ahmad, Md. Fayej

2012-01-01

Arsenic is widely distributed in nature in the air, water and soil. Acute and chronic arsenic exposure by drinking water has been reported in many countries, especially Argentina, Bangladesh, India, Mexico, Mongolia, Thailand and Taiwan. There are many techniques used to remove arsenic from drinking water. Among them reverse osmosis is widely used. Therefore the purpose of this study is to find the conditions favorable for removal of arsenic from drinking water by using reverse osmosis ...

Structures of water molecules in carbon nanotubes under electric fields

International Nuclear Information System (INIS)

Winarto,; Takaiwa, Daisuke; Yamamoto, Eiji; Yasuoka, Kenji

2015-01-01

Carbon nanotubes (CNTs) are promising for water transport through membranes and for use as nano-pumps. The development of CNT-based nanofluidic devices, however, requires a better understanding of the properties of water molecules in CNTs because they can be very different from those in the bulk. Using all-atom molecular dynamics simulations, we investigate the effect of axial electric fields on the structure of water molecules in CNTs having diameters ranging from (7,7) to (10,10). The water dipole moments were aligned parallel to the electric field, which increases the density of water inside the CNTs and forms ordered ice-like structures. The electric field induces the transition from liquid to ice nanotubes in a wide range of CNT diameters. Moreover, we found an increase in the lifetime of hydrogen bonds for water structures in the CNTs. Fast librational motion breaks some hydrogen bonds, but the molecular pairs do not separate and the hydrogen bonds reform. Thus, hydrogen bonds maintain the water structure in the CNTs, and the water molecules move collectively, decreasing the axial diffusion coefficient and permeation rate

ADSORPTIVE REMOVAL OF FLUORIDE FROM WATER USING ...

African Journals Online (AJOL)

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Currently available treatment methods for removal of excess fluoride from water are broadly divided into three ... the application of nanoparticles as sorbents for fluoride removal. Sundaram [26] studied the ... Characterization of adsorbent.

Approximative Krieger-Nelkin orientation averaging and anisotropy of water molecules vibrations

International Nuclear Information System (INIS)

Markovic, M.I.

1974-01-01

Quantum-mechanics approach of water molecules dynamics should be taken into account for precise theoretical calculation of differential scattering cross sections of neutrons. Krieger and Nelkin have proposed an approximate method for averaging orientation of molecules regarding directions of incoming and scattered neutron. This paper shows that this approach can be successfully applied for general shape of water molecule vibration anisotropy

Iron and manganese removal from drinking water

Directory of Open Access Journals (Sweden)

Daniela-Elena Pascu

2016-04-01

Full Text Available The purpose of the present study is to find a suitable method for removal of iron and manganese from ground water, considering bothlocal economical and environmental aspects. Ground water is a highly important source of drinking water in Romania. Ground water is naturally pure from bacteria at a 25 m depth or more. However, solved metals may occur and if the levels are too high, the water is not drinkable. Different processes, such as electrochemical and combined electrochemical-adsorption methods have been applied to determine metals content in accordance to reports of National Water Agency from Romania (ANAR. Every water source contains dissolved or particulate compounds. The concentrations of these compounds can affect health, productivity, compliance requirements, or serviceability and cannot be economically removed by conventional filtration means. In this study, we made a comparison between the electrochemical and adsorption methods (using membranes. Both methods have been used to evaluate the efficiency of iron and manganese removal at various times and temperatures. We used two membrane types: composite and cellulose, respectively. Different approaches, including lowering the initial current density and increasing the initial pH were applied. Reaction kinetics was achieved using mathematical models: Jura and Temkin.

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.

Nitrate Removal from Ground Water: A Review

OpenAIRE

Archna; Sharma, Surinder K.; Sobti, Ranbir Chander

2012-01-01

Nitrate contamination of ground water resources has increased in Asia, Europe, United States, and various other parts of the world. This trend has raised concern as nitrates cause methemoglobinemia and cancer. Several treatment processes can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that biological denitrification is more acceptable for nitrate removal than reverse osmosis and ion ex...

Quantum Electric Dipole Lattice - Water Molecules Confined to Nanocavities in Beryl

Science.gov (United States)

Dressel, Martin; Zhukova, Elena S.; Thomas, Victor G.; Gorshunov, Boris P.

2018-02-01

Water is subject to intense investigations due to its importance in biological matter but keeps many of its secrets. Here, we unveil an even other aspect by confining H2O molecules to nanosize cages. Our THz and infrared spectra of water in the gemstone beryl evidence quantum tunneling of H2O molecules in the crystal lattice. The water molecules are spread out when confined in a nanocage. In combination with low-frequency dielectric measurements, we were also able to show that dipolar coupling among the H2O molecules leads towards a ferroelectric state at low temperatures. Upon cooling, a ferroelectric soft mode shifts through the THz range. Only quantum fluctuations prevent perfect macroscopic order to be fully achieved. Beside the significance to life science and possible application, nanoconfined water may become the prime example of a quantum electric dipolar lattice.

REMOVAL OF HEXAVALENT CHROMIUM FROM DRINKING WATER

Directory of Open Access Journals (Sweden)

A. R. Asgari ، F. Vaezi ، S. Nasseri ، O. Dördelmann ، A. H. Mahvi ، E. Dehghani Fard

2008-10-01

Full Text Available Removal of chromium can be accomplished by various methods but none of them is cost-effective in meeting drinking water standards. For this study, granular ferric hydroxide was used as adsorbent for removal of hexavalent chromium. Besides, the effects of changing contact time, pH and concentrations of competitive anions were determined for different amounts of granular ferric hydroxide. It was found that granular ferric hydroxide has a high capacity for adsorption of hexavalent chromium from water at pH≤7 and in 90 min contact time. Maximum adsorption capacity was determined to be 0.788 mg Cr+6/g granular ferric hydroxide. Although relatively good adsorption of sulfate and chloride had been specified in this study, the interfering effects of these two anions had not been detected in concentrations of 200 and 400 mg/L. The absorbability of hexavalent chromium by granular ferric hydroxide could be expressed by Freundlich isotherm with R2>0.968. However, the disadvantage was that the iron concentration in water was increased by the granular ferric hydroxide. Nevertheless, granular ferric hydroxide is a promising adsorbent for chromium removal, even in the presence of other interfering compounds, because granular ferric hydroxide treatment can easily be accomplished and removal of excess iron is a simple practice for conventional water treatment plants. Thus, this method could be regarded as a safe and convenient solution to the problem of chromium-polluted water resources.

THE REMOVAL OF GLYPHOSATE FROM DRINKING WATER

Science.gov (United States)

The effectiveness of granulated activated carbon (GAC), packed activated carbon (PAC), conventional treatment, membranes, and oxidation for removing glyphosate from natural waters is evaluated. Results indicate that GAC and PAC are not effective in removing glyphosate, while oxid...

Compositions and methods for removing arsenic in water

Science.gov (United States)

Gadgil, Ashok Jagannth [El Cerrito, CA

2011-02-22

Compositions and methods and for contaminants from water are provided. The compositions comprise ferric hydroxide and ferric oxyhydride coated substrates for use in removing the contaminant from the water. Contacting water bearing the contaminant with the substrates can substantially reduce contaminant levels therein. Methods of oxidizing the contaminants in water to facilitate their removal by the ferric hydroxide and ferric oxyhydride coated substrates are also provided. The contaminants include, but are not limited to, arsenic, selenium, uranium, lead, cadmium, nickel, copper, zinc, chromium and vanadium, their oxides and soluble salts thereof.

Distribution of binding energies of a water molecule in the water liquid-vapor interface

Energy Technology Data Exchange (ETDEWEB)

Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV

2008-01-01

Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

[The method to remove nitrite from tap water by tea].

Science.gov (United States)

Lu, M; Chen, L; Xian, H

1997-03-01

Drinking water (tap water) is polluted in pipelines by bacteria after long distance transportation. The water contains nitrite (NO2-) which is potentially harmful to human health. The nitrite concentrations range from 0.10 to 2.0 mg/L. Our experiment proved that NO2- could not be removed by boiling, but could be removed by tea. As a natural antioxidant, tea contains several antioxidants, such as ascorbic acid and catechins, which removed NO2- from tap water effectively.

Analysis of microplastics and their removal from water

OpenAIRE

Oladejo, Abiola

2017-01-01

Removal of microplastics from water was studied using extraction with oil. The aim of the thesis was to remove microplastics from water using an organic medium, and to analyse the amount of microplastics in the media involved. The separation of different microplastic types was done by conducting experiments in the laboratory. The microplastics were made by grinding and sieving plastics with a grinding machine before adding them to water and oil, which serves as the organic medium. Tw...

Effects of water chemistry on arsenic removal from drinking water by electrocoagulation.

Science.gov (United States)

Wan, Wei; Pepping, Troy J; Banerji, Tuhin; Chaudhari, Sanjeev; Giammar, Daniel E

2011-01-01

Exposure to arsenic through drinking water poses a threat to human health. Electrocoagulation is a water treatment technology that involves electrolytic oxidation of anode materials and in-situ generation of coagulant. The electrochemical generation of coagulant is an alternative to using chemical coagulants, and the process can also oxidize As(III) to As(V). Batch electrocoagulation experiments were performed in the laboratory using iron electrodes. The experiments quantified the effects of pH, initial arsenic concentration and oxidation state, and concentrations of dissolved phosphate, silica and sulfate on the rate and extent of arsenic removal. The iron generated during electrocoagulation precipitated as lepidocrocite (γ-FeOOH), except when dissolved silica was present, and arsenic was removed by adsorption to the lepidocrocite. Arsenic removal was slower at higher pH. When solutions initially contained As(III), a portion of the As(III) was oxidized to As(V) during electrocoagulation. As(V) removal was faster than As(III) removal. The presence of 1 and 4 mg/L phosphate inhibited arsenic removal, while the presence of 5 and 20 mg/L silica or 10 and 50 mg/L sulfate had no significant effect on arsenic removal. For most conditions examined in this study, over 99.9% arsenic removal efficiency was achieved. Electrocoagulation was also highly effective at removing arsenic from drinking water in field trials conducted in a village in Eastern India. By using operation times long enough to produce sufficient iron oxide for removal of both phosphate and arsenate, the performance of the systems in field trials was not inhibited by high phosphate concentrations. Copyright © 2010 Elsevier Ltd. All rights reserved.

N-Basin water removal plan

International Nuclear Information System (INIS)

Nellesen, A.L.

1997-07-01

This ALARA review provides a description of the engineering and administrative controls used to manage personnel exposure, control contamination levels, and airborne radioactivity concentrations, while removing water and stabilizing surfaces in the 105-N Fuel Storage Building

Process for removing sulfate anions from waste water

Science.gov (United States)

Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

1997-01-01

A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

Dynamics of water molecules in the active-site cavity of human cytochromes P450

DEFF Research Database (Denmark)

Rydberg, Patrik; Rod, Thomas Holm; Olsen, Lars

2007-01-01

We have studied the dynamics of water molecules in six crystal structures of four human cytochromes P450, 2A6, 2C8, 2C9, and 3A4, with molecular dynamics simulations. In the crystal structures, only a few water molecules are seen and the reported sizes of the active-site cavity vary a lot....... In the simulations, the cavities are completely filled with water molecules, although with approximately 20% lower density than in bulk water. The 2A6 protein differs from the other three in that it has a very small cavity with only two water molecules and no exchange with the surroundings. The other three proteins...... channels, through which there is a quite frequent exchange of water molecules (one molecule is exchanged every 30-200 ps), except in 2A6. Most of the channels are observed also in the crystal structures, but two to three channels in each protein open only during the simulations. There are no water...

Turbidity and microbes removal from water using an electrochemical filter

International Nuclear Information System (INIS)

Venkateswaran, G.; Gokhale, B.K.; Belapurkar, A.D.; Kumbhar, A.G.; Balaji, V.

2004-01-01

An in-house designed and fabricated Electrochemical fibrous graphite filter (ECF) was used to remove turbidity and microbes. The filter was found to be effective in removing sub micron size indium turbidity from RAPS-1 moderator water, iron turbidity from Active Process Cooling Water (APCW) of Kaiga Generating Station and microbial reduction from process cooling water RAPS-2. Unlike conventional turbidity removal by addition of coagulants and biocide chemical additions for purification, ECF is a clean way to remove the turbidity without contaminating the system and is best suited for close loop systems

GLYPHOSATE REMOVAL FROM DRINKING WATER

Science.gov (United States)

Activated-carbon, oxidation, conventional-treatment, filtration, and membrane studies are conducted to determine which process is best suited to remove the herbicide glyphosate from potable water. Both bench-scale and pilot-scale studies are completed. Computer models are used ...

Quantification of the Intracellular Life Time of Water Molecules to Measure Transport Rates of Human Aquaglyceroporins.

Science.gov (United States)

Palmgren, Madelene; Hernebring, Malin; Eriksson, Stefanie; Elbing, Karin; Geijer, Cecilia; Lasič, Samo; Dahl, Peter; Hansen, Jesper S; Topgaard, Daniel; Lindkvist-Petersson, Karin

2017-12-01

Orthodox aquaporins are transmembrane channel proteins that facilitate rapid diffusion of water, while aquaglyceroporins facilitate the diffusion of small uncharged molecules such as glycerol and arsenic trioxide. Aquaglyceroporins play important roles in human physiology, in particular for glycerol metabolism and arsenic detoxification. We have developed a unique system applying the strain of the yeast Pichia pastoris, where the endogenous aquaporins/aquaglyceroporins have been removed and human aquaglyceroporins AQP3, AQP7, and AQP9 are recombinantly expressed enabling comparative permeability measurements between the expressed proteins. Using a newly established Nuclear Magnetic Resonance approach based on measurement of the intracellular life time of water, we propose that human aquaglyceroporins are poor facilitators of water and that the water transport efficiency is similar to that of passive diffusion across native cell membranes. This is distinctly different from glycerol and arsenic trioxide, where high glycerol transport efficiency was recorded.

Structural Arrangement of Water Molecules around Highly Charged Nanoparticles: Molecular Dynamics Simulation

International Nuclear Information System (INIS)

Kim, Eunae; Yeom, Min Sun

2014-01-01

Molecular dynamics simulations were performed to understand the structural arrangement of water molecules around highly charged nanoparticles under aqueous conditions. The effect of two highly charged nanoparticles on the solvation charge asymmetry has been examined. We calculated the radial distribution functions of the components of water molecules around nanoparticles which have four charge types at two different salt concentrations. Even though the distributions of water molecules surrounding a sodium ion and a chloride ion are hardly affected by the charges of nanoparticles and the salt concentrations, those around highly charged nanoparticles are strongly influenced by the charges of nanoparticles, but hardly by the charges of nanoparticles and salt concentrations. We find that the distributions of hydrogen atoms in water molecules around one highly charged nanoparticle are dependent on the magnitude of the nanoparticle charge

Effect of color removal agent on textiles waste water

International Nuclear Information System (INIS)

Khomsaton Abu Bakar; Selambakknu, Sarala; Jamaliah Shariff; Ting, Teo Ming; Khairul Zaman Dahlan

2010-01-01

The effect of color removal agent (CRA) on textile waste water has been studied. The aim of this work is to determine the optimum condition for CRA to react on the textile waste water and to see the effect of CRA on waste water with different Chemical Oxygen Demand. 8 ml CRA was used to treat 800 mls of sample with various COD ranging between 2500 mg/ l-500 mg/ l. The results showed that CRA totally remove the colour of textile waste water at pH ranging from 6 to 8. At an optimum condition CRA works efficiently on waste water with COD 2300 mg/ l for reduction of suspended solid and turbidity. It also observed, sludge accumulation was depended on COD concentration. Color removal curves for different initial COD concentration also obtained. (author)

A Single-Molecule Propyne Trap: Highly Efficient Removal of Propyne from Propylene with Anion-Pillared Ultramicroporous Materials.

Science.gov (United States)

Yang, Lifeng; Cui, Xili; Yang, Qiwei; Qian, Siheng; Wu, Hui; Bao, Zongbi; Zhang, Zhiguo; Ren, Qilong; Zhou, Wei; Chen, Banglin; Xing, Huabin

2018-03-01

Propyne/propylene (C 3 H 4 /C 3 H 6 ) separation is a critical process for the production of polymer-grade C 3 H 6 . However, optimization of the structure of porous materials for the highly efficient removal of C 3 H 4 from C 3 H 6 remains challenging due to their similar structures and ultralow C 3 H 4 concentration. Here, it is first reported that hybrid ultramicroporous materials with pillared inorganic anions (SiF 6 2- = SIFSIX, NbOF 5 2- = NbOFFIVE) can serve as highly selective C 3 H 4 traps for the removal of trace C 3 H 4 from C 3 H 6 . Especially, it is revealed that the pyrazine-based ultramicroporous material with square grid structure for which the pore shape and functional site disposition can be varied in 0.1-0.5 Å scale to match both the shape and interacting sites of guest molecule is an interesting single-molecule trap for C 3 H 4 molecule. The pyrazine-based single-molecule trap enables extremely high C 3 H 4 uptake under ultralow concentration (2.65 mmol g -1 at 3000 ppm, one C 3 H 4 per unit cell) and record selectivity over C 3 H 6 at 298 K (>250). The single-molecule binding mode for C 3 H 4 within ultramicroporous material is validated by X-ray diffraction experiments and modeling studies. The breakthrough experiments confirm that anion-pillared ultramicroporous materials set new benchmarks for the removal of ultralow concentration C 3 H 4 (1000 ppm on SIFSIX-3-Ni, and 10 000 ppm on SIFSIX-2-Cu-i) from C 3 H 6 . © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vibrational properties of water molecules adsorbed in different zeolitic frameworks

International Nuclear Information System (INIS)

Crupi, V; Longo, F; Majolino, D; Venuti, V

2006-01-01

The perturbation of water 'sorbed' in samples of zeolites of different structural type, genesis, and cation composition (K-, Na-, Mg- and Ca-rich zeolites), namely the CHA framework of a synthetic K-chabazite, the LTA framework of synthetic Na-A and Mg50-A zeolites, and the NAT framework of a natural scolecite, has been studied by FTIR-ATR spectroscopy, in the -10 to +80 o C temperature range. The aim was to show how differences in the chemical composition and/or in the topology of the zeolite framework and, in particular, the possibility for the guest water molecules to develop guest-guest and/or host-guest interactions, lead to substantial differences in their vibrational dynamical properties. The spectra, collected in the O-H stretching and H 2 O bending mode regions, are complex, with multiple bands being observed. As far as water in the CHA and LTA frameworks is concerned, whose behaviour is governed by the balance of water-water, water-framework and water-extra-framework cations interactions, the assignment of the resolved components of the O-H stretching band has been discussed by fitting the band shapes into individual components attributed to H 2 O molecules engaged in different degrees of hydrogen bonding. A detailed quantitative picture of the connectivity pattern of water, as a function of temperature and according to the chemical and topological properties of the environment, is furnished. The H 2 O bending vibrational bands give additional information that perfectly agrees with the results obtained from the analysis of the O-H stretching spectral region. In the case of scolecite, a small-pored zeolite where water-water interactions are eliminated, the increased complexity observed in the infrared spectra in the O-H stretching and H 2 O bending regions was explained as due to the hydrogen bonding between the water molecules and the network, and also with the extra-framework cation. Furthermore, these observations have been correlated with the different

7 CFR 701.53 - Debris removal and water for livestock.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Debris removal and water for livestock. 701.53 Section... RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART § 701.53 Debris removal and water for livestock..., and for providing water for livestock. [71 FR 30265, May 26, 2006] ...

Removal efficiency of water purifier and adsorbent for iodine, cesium, strontium, barium and zirconium in drinking water.

Science.gov (United States)

Sato, Itaru; Kudo, Hiroaki; Tsuda, Shuji

2011-01-01

The severe incident of Fukushima Daiichi Nuclear Power Station has caused radioactive contamination of environment including drinking water. Radioactive iodine, cesium, strontium, barium and zirconium are hazardous fission products because of the high yield and/or relatively long half-life. In the present study, 4 pot-type water purifiers and several adsorbents were examined for the removal effects on these elements from drinking water. Iodide, iodate, cesium and barium were removed by all water purifiers with efficiencies about 85%, 40%, 75-90% and higher than 85%, respectively. These efficiencies lasted for 200 l, which is near the recommended limits for use of filter cartridges, without decay. Strontium was removed with initial efficiencies from 70% to 100%, but the efficiencies were slightly decreased by use. Zirconium was removed by two models, but hardly removed by the other models. Synthetic zeolite A4 efficiently removed cesium, strontium and barium, but had no effect on iodine and zirconium. Natural zeolite, mordenite, removed cesium with an efficiency as high as zeolite A4, but the removal efficiencies for strontium and barium were far less than those of zeolite A4. Activated carbon had little removal effects on these elements. In case of radioactive contamination of tap water, water purifiers may be available for convenient decontamination of drinking water in the home.

The hydrophilic/hydrophobic ratio vs. dissolved organics removal by coagulation – A review

Directory of Open Access Journals (Sweden)

Djamel Ghernaout

2014-07-01

Full Text Available This review discusses the hydrophilic/hydrophobic ratio as a function of the hydrophilic and hydrophobic contents removal by coagulation process. It is well established that coagulation process could bring a reduction in dissolved organic carbon of around 30–60% by increasing the coagulant dose and optimising reaction pH, in which large organic molecules with hydrophobic property was removed preferentially. Furthermore, the literature affirmed that the greater removal of UV-absorbing substances indicates that alum coagulation preferentially removed the hydrophobic fraction of the total organic carbon. For the hydrophobic fraction, it needs to be removed entirely without its transformation into hydrophilic fractions by coagulation process avoiding pre-chlorination/pre-oxidation due to the risk of organic molecules fragmentation. Determining the exact numerical values of the hydrophilic/hydrophobic ratio for raw water and treated water at different stages of the treatment processes in a water treatment plant, as for the DCO/DBO5 ratio in the case of wastewater treatment, would help on more focusing on OM control and removal.

Uranium removal from water by five aquatic plants

International Nuclear Information System (INIS)

Hu Nan; Ding Dexin; Li Guangyue; Wang Yongdong; Li Le; Zheng Jifang

2012-01-01

Hydroponic solution culture experiments were conducted on the growth of Eichhornia crassipes, Lemna minor L, Azolla imbircata, Potamogeton crispus, and Alligator alternanthera Herb in water with 0.15, 1.50 and 15.00 mg . L -1 concentrations of uranium, and on the uranium removal from the water by the aquatic plants. For the 21 days of hydroponic solution culture experiments, Azolla imbircata exhibited the strongest resistance to uranium and its growth inhibition rates induced by the water with 0.15, 1.50 and 15.00 mg · L -1 concentrations of uranium were 4.56%, 2.48%, 6.79%, respectively, and the uranium removal rates from the water by the plant amounted to 94%, 97% and 92%, respectively. Further experiments revealed that the most uranium removal could be achieved when 7.5 g Azolla imbircata was grown in 1 L of water, and the time required for the plant to reduce the uranium concentration in water with 1.25, 2.50, 5.00 and 10.00 mg · L -l concentrations of uranium below that stipulated in the national emission standards of China were 17, 19, 23 and 25 days, respectively. The results have laid foundation for further studies of phytoremediation of uranium contaminated water. (authors)

Uranium removal from the water supply

International Nuclear Information System (INIS)

Miranzadeh, Mohammad Bagher.

1996-01-01

Uranium can be naturally occurring radionuclides that contaminate some potable water supplies. Uranium is found both in surface water and ground water supplies. The United States Environmental Protection Agency recently proposed a maximum contaminant of 20 micro gram/liter for uranium because of concerns about its association with kidney disease and cancer. uranium can be removed from the supply by strong base anion-resin. Exhausted resin is regenerated by sodium chloride solution. (Author)

Integration or segregation: how do molecules behave at oil/water interfaces?

Science.gov (United States)

Moore, F G; Richmond, G L

2008-06-01

It has been over 250 years since Benjamin Franklin, fascinated with the wave-stilling effect of oil on water, performed his famous oil-drop experiments; nevertheless, the behavior of water molecules adjacent to hydrophobic surfaces continues to fascinate today. In the 18th century, the calming of the seas seemed the most pertinent application of such knowledge; today, we understand that oil-on-water phenomena underlie a range of important chemical, physical, and biological processes, including micelle and membrane formation, protein folding, chemical separation, oil extraction, nanoparticle formation, and interfacial polymerization. Beyond classical experiments of the oil-water interface, recent interest has focused on deriving a molecular-level picture of this interface or, more generally, of water molecules positioned next to any hydrophobic surface. This Account summarizes more than a decade's work from our laboratories aimed at understanding the nature of the hydrogen bonding occurring between water and a series of organic liquids in contact. Although the common perception is that water molecules and oil molecules positioned at the interface between the immiscible liquids want nothing to do with one another, we have found that weak interactions between these hydrophilic and hydrophobic molecules lead to interesting interfacial behavior, including highly oriented water molecules and layering of the organic medium that extends several molecular layers deep into the bulk organic liquid. For some organic liquids, penetration of oriented water into the organic layer is also apparent, facilitated by molecular interactions established at the molecularly thin region of first contact between the two liquids. The studies involve a combined experimental and computational approach. The primary experimental tool that we have used is vibrational sum frequency spectroscopy (VSFS), a powerful surface-specific vibrational spectroscopic method for measuring the molecular

Carbon Nanotubes Technology for Removal of Arsenic from Water

Directory of Open Access Journals (Sweden)

Ali Naghizadeh

2012-08-01

Full Text Available Please cite this article as: Naghizadeh A, Yari AR, Tashauoei HR, Mahdavi M, Derakhshani E, Rahimi R, Bahmani P. Carbon nanotubes technology for removal of arsenic from water. Arch Hyg Sci 2012;1(1:6-11. Aims of the Study: This study was aimed to investigate the adsorption mechanism of the arsenic removal from water by using carbon nanotubes in continuous adsorption column. Materials & Methods: Independent variables including carbon nanotubes dosage, contact time and breakthrough point were carried out to determine the influence of these parameters on the adsorption capacity of the arsenic from water. Results: Adsorption capacities of single wall and multiwall carbon nanotubes were about 148 mg/g and 95 mg/g respectively. The experimental data were analyzed using Langmuir and Freundlich isotherm models and equilibrium data indicate the best fit obtained with Langmuir isotherm model. Conclusions: Carbon nanotubes can be considered as a promising adsorbent for the removal of arsenic from large volume of aqueous solutions. References: 1. Lomaquahu ES, Smith AH. Feasibility of new epidemiology studies on arsenic exposures at low levels. AWWA Inorganic Contaminants Workshop. San Antonio; 1998. 2. Burkel RS, Stoll RC. Naturally occurring arsenic in sandstone aquifer water supply wells of North Eastern Wisconsin. Ground Water Monit Remediat 1999;19(2:114-21. 3. Mondal P, Majumder CB, Mohanty B. Laboratory based approaches for arsenic remediation from contaminated water: recent developments. J Hazard Mater 2006;137(1: 464-79. 4. Meenakshi RCM. Arsenic removal from water: a review. Asian J Water Environ Pollut 2006;3(1:133-9. 5. Wickramasinghe SR, Binbing H, Zimbron J, Shen Z, Karim MN. Arsenic removal by coagulation and filtration: comparison of ground waters from United States and Bangladesh. Desalination 2004;169:231-44. 6. Hossain MF. Arsenic contamination in Bangladesh-an overview. Agric Ecosyst Environ 2006;113(1-4:1-16. 7. USEPA, Arsenic. Final

Removal of some radionuclides from water by bioaccumulation

International Nuclear Information System (INIS)

Miskovic, D.; Conkic, L.; Dalmacija, B.; Gantar, M.

1992-01-01

First objective of this study was to investigate the application of biologically activated carbon (BAC) as well as its comparison to adsorption, with the aim of removing some radionuclides from water. The isotopes Cs 134 and Cs 137 were bioaccumulated by BAC up to 50%, while the I 131 isotope was only physicochemically adsorbed (about 40%). Also, the process of radionuclides (Cs 137 , Ce 139 , Co 57 , Co 60 ) fixation on blue-green algae (Nostoc sp.) was investigated. The kinetics of the removal of these radionuclides from water was recorded. It was found that after a contact period of about half an hour 40-70% of the activity was removed. (Author)

Method of arsenic removal from water

Science.gov (United States)

Gadgil, Ashok

2010-10-26

A method for low-cost arsenic removal from drinking water using chemically prepared bottom ash pre-treated with ferrous sulfate and then sodium hydroxide. Deposits on the surface of particles of bottom ash form of activated iron adsorbent with a high affinity for arsenic. In laboratory tests, a miniscule 5 grams of pre-treated bottom ash was sufficient to remove the arsenic from 2 liters of 2400 ppb (parts per billion) arsenic-laden water to a level below 50 ppb (the present United States Environmental Protection Agency limit). By increasing the amount of pre-treated bottom ash, even lower levels of post-treatment arsenic are expected. It is further expected that this invention supplies a very low-cost solution to arsenic poisoning for large population segments.

Fast Rotational Diffusion of Water Molecules in a 2D Hydrogen Bond Network at Cryogenic Temperatures

Science.gov (United States)

Prisk, T. R.; Hoffmann, C.; Kolesnikov, A. I.; Mamontov, E.; Podlesnyak, A. A.; Wang, X.; Kent, P. R. C.; Anovitz, L. M.

2018-05-01

Individual water molecules or small clusters of water molecules contained within microporous minerals present an extreme case of confinement where the local structure of hydrogen bond networks are dramatically altered from bulk water. In the zinc silicate hemimorphite, the water molecules form a two-dimensional hydrogen bond network with hydroxyl groups in the crystal framework. Here, we present a combined experimental and theoretical study of the structure and dynamics of water molecules within this network. The water molecules undergo a continuous phase transition in their orientational configuration analogous to a two-dimensional Ising model. The incoherent dynamic structure factor reveals two thermally activated relaxation processes, one on a subpicosecond timescale and another on a 10-100 ps timescale, between 70 and 130 K. The slow process is an in-plane reorientation of the water molecule involving the breaking of hydrogen bonds with a framework that, despite the low temperatures involved, is analogous to rotational diffusion of water molecules in the bulk liquid. The fast process is a localized motion of the water molecule with no apparent analogs among known bulk or confined phases of water.

Hydroxyl and water molecule orientations in trypsin: Comparison to molecular dynamics structures

Energy Technology Data Exchange (ETDEWEB)

McDowell, R.S.; Kossiakoff, A.A. [Genentech, Inc., South San Francisco, CA (United States)

1994-12-31

A comparison is presented of experimentally observed hydroxyl and water hydrogens in trypsin determined from neutron density maps with the results of a 140ps molecular dynamics (MD) simulation. Experimental determination of hydrogen and deuterium atom positions in molecules as large as proteins is a unique capability of neutron diffraction. The comparison addresses the degree to which a standard force-field approach can adequately describe the local electrostatic and van der Waals forces that determine the orientations of these hydrogens. Neutron densities, derived from 2.1{Angstrom} D{sub 2}O-H{sub 2}O difference Fourier maps, provide a database of 27 well-ordered hydroxyl hydrogens. Most of the simulated hydroxyl orientations are within a standard deviation of the experimentally-observed positions, including several examples in which both the simulation and the neutron density indicate that a hydroxyl group is shifted from a {open_quote}standard{close_quote} rotamer. For the most highly ordered water molecules, the hydrogen distributions calculated from the trajectory were in good agreement with neutron density; simulated water molecules that displayed multiple hydrogen bonding networks had correspondingly broadened neutron density profiles. This comparison was facilitated by development of a method to construct a pseudo 2{Angstrom} density map based on the hydrogen atom distributions from the simulation. The degree of disorder of internal water molecules is shown to result primarily from the electrostatic environment surrounding that water molecule as opposed to the cavity size available to the molecule. A method is presented for comparing the discrete observations sampled in a dynamics trajectory with the time- averaged data obtained from X-ray or neutron diffraction studies. This method is particularly useful for statically-disordered water molecules, in which the average location assigned from a trajectory may represent a site of relatively low occupancy.

TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

Directory of Open Access Journals (Sweden)

RAISA NASTAS

2012-03-01

Full Text Available Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the type of impregnated heteroatom (N, O, or metals (Fe, Cu, Ni, on removal of hydrogen sulfide species and nitrite ions have been researched. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous ground waters. Comparative analysis of carbonaceous adsorbents reveals the importance of surface chemistry for oxidation of nitrite ions.

Transport of water molecules through noncylindrical pores in multilayer nanoporous graphene.

Science.gov (United States)

Shahbabaei, Majid; Kim, Daejoong

2017-08-09

In this study, molecular dynamics (MD) simulations are used to examine the water transport properties through asymmetric hourglass-shaped pores in multilayer nanoporous graphene with a constant interlayer separation of 6 Å. The properties of the tested asymmetric hourglass-shaped pores [with the models having long cone (l 1 , -P) and short cone (l 2 , +P) entrances] are compared to a symmetric pore model. The study findings indicate that the water occupancy increases across the asymmetric pore (l 1 , -P) compared to (l 2 , +P), because of the length effect. The asymmetric pore, (l 1 , -P), yields higher flux compared to (l 2 , +P) and even the symmetric model, which can be attributed to the increase in the hydrogen bonds. In addition, the single-file water molecules across the narrowest pore diameter inside the (l 2 , +P) pore exhibit higher viscosity compared to those in the (l 1 , -P) pore because of the increase in the water layering effect. Moreover, it is found that the permeability inside the multilayer hourglass-shaped pore depends on the length of the flow path of the water molecules before approaching the layer with the smallest pore diameter. The probability of dipole orientation exhibits wider distribution inside the (l 1 , -P) system compared to (l 2 , +P), implying an enhanced formation of hydrogen bonding of water molecules. This results in the fast flow of water molecules. The MD trajectory shows that the dipole orientation across the single-layer graphene has frequently flipped compared to the dipole orientation across the pores in multilayer graphene, which is maintained during the whole simulation time (although the dipole orientation has flipped for a few picoseconds at the beginning of the simulation). This can be attributed to the energy barrier induced by the individual layer. The diffusion coefficient of water molecules inside the (l 2 , +P) system increases with pressure difference, however, it decreases inside the (l 1 , -P) system because

Acceleration induced water removal from ear canals.

Science.gov (United States)

Kang, Hosung; Averett, Katelee; Jung, Sunghwan

2017-11-01

Children and adults commonly experience having water trapped in the ear canals after swimming. To remove the water, individuals will shake their head sideways. Since a child's ear canal has a smaller diameter, it requires more acceleration of the head to remove the trapped water. In this study, we theoretically and experimentally investigated the acceleration required to break the surface meniscus of the water in artificial ear canals and hydrophobic-coated glass tubes. In experiments, ear canal models were 3D-printed from a CT-scanned human head. Also, glass tubes were coated with silane to match the hydrophobicity in ear canals. Then, using a linear stage, we measured the acceleration values required to forcefully eject the water from the artificial ear canals and glass tubes. A theoretical model was developed to predict the critical acceleration at a given tube diameter and water volume by using a modified Rayleigh-Taylor instability. Furthermore, this research can shed light on the potential of long-term brain injury and damage by shaking the head to push the water out of the ear canal. This research was supported by National Science Foundation Grant CBET-1604424.

Laser removal of water repellent treatments on limestone

Energy Technology Data Exchange (ETDEWEB)

Gomez-Heras, Miguel; Alvarez de Buergo, Monica; Rebollar, Esther; Oujja, Mohamed; Castillejo, Marta; Fort, Rafael

2003-12-15

Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

Cyclic process of simazine removal from waters by adsorption on zeolite H-Y and its regeneration by thermal treatment

International Nuclear Information System (INIS)

Sannino, Filomena; Ruocco, Silvia; Marocco, Antonello; Esposito, Serena; Pansini, Michele

2012-01-01

Highlights: ► Bringing agrochemical concentration below the law limit allowed in wastewaters. ► Regenerating the adsorbent which can be used again in the cyclic process. ► Destroying the agrochemical molecules by combustion. - Abstract: Removal of the agrochemical simazine from polluted waters through adsorption by zeolite Y in its protonic form was studied. The investigated parameters were: pH, time, initial simazine concentration and solid/liquid ratio. An iterative process of simazine removal from waters is proposed, featuring: (i) final agrochemical concentration well below 0.05 mg/dm 3 , the maximum concentration allowed by Italian laws in wastewaters; (ii) regeneration of the adsorbent by a few minutes thermal treatment in air at about 500 °C, which results in the combustion of simazine without damage of the adsorbent; (iii) destruction of the agrochemical compound by combustion.

Shear-stress-induced structural arrangement of water molecules in nanoscale Couette flow with slipping at wall boundary

International Nuclear Information System (INIS)

Lin, Jau-Wen

2014-01-01

This study investigated the structuring of water molecules in a nanoscale Couette flow with the upper plate subjected to lateral forces with various magnitudes and water slipping against a metal wall. It was found that when the upper plate is subjected to a force, the water body deforms into a parallelepiped. Water molecules in the channel are then gradually arranged into lattice positions, creating a layered structure. The structural arrangement of water molecules is caused by the water molecules accommodating themselves to the increase in energy under the application of a lateral force on the moving plate. The ordering arrangement of water molecules increases the rotational degree of freedom, allowing the molecules to increase their Coulomb potential energy through polar rotation that accounts for the energy input through the upper plate. With a force continuously applied to the upper plate, the water molecules in contact with the upper plate move forward until slip between the water and upper plate occurs. The relation between the structural arrangement of water molecules, slip at the wall, and the shear force is studied. The relation between the slip and the locking/unlocking of water molecules to metal atoms is also studied

Efficiency of lead removal from drinking water using cationic resin Purolite

Directory of Open Access Journals (Sweden)

Ashour Mohammad Merganpour

2015-01-01

Full Text Available Background: Today, issues such as water shortage, difficulties and costs related to supplying safe water, and anomalous concentrations of heavy metals in groundwater and surface water resources, doubled the necessity of access to technical methods on removing these pollutants from water resources. Methods: In this lab study, cationic resin Purolite S-930 (with co-polymer styrene di-vinyl benzene structure was used for lead removal from drinking water containing up to 22 μg/L. Using statistical analysis and designing a full factorial experiment are the most important effective parameters on lead removal obtained through ion exchange process. Results: Analysis of response and interaction parameters of ion exchange showed that the resin column height has maximum and pH value has minimum effect on the efficiency of lead removal from aquatic environment. Trinary interaction of “effective size, flow rate, resin column high” has the most important for lead removal efficiency in this system. So the maximum efficiency was obtained at the mesh = 40, bed height =1.6 meter, and pH= 6.5. At the best operation conditions, ability to remove 95.42% of lead concentration can be achieved. Conclusion: Using the resin Purolite S-930 during 21-day service with 91.12% of mean lead removal ratio from drinking water is an economic and technical feasibility.

Zirconium-Based Metal–Organic Framework for Removal of Perrhenate from Water

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Debasis; Xu, Wenqian; Nie, Zimin; Johnson, Lewis E. V.; Coghlan, Campbell; Sushko, Maria L.; Kim, Dongsang; Schweiger, Michael J.; Kruger, Albert A.; Doonan, Christian J.; Thallapally, Praveen K.

2016-09-06

Efficient removal of pertechnetate (TcO4-) anions from liquid waste or melter off-gas solution for alternative treatment is one of the promising options to manage 99Tc in legacy nuclear waste. Safe immobilization of 99Tc is of major importance due to its long half-life (t1/2= 2.13 × 105 yrs) and environmental mobility. Different types of inorganic and solid state ion-exchange materials such as layered double hydroxides have been shown to absorb TcO4- anions from water. However, both high capacity and selectivity have yet to be achieved in a single material. Herein, we show that a protonated version of an ultra-stable zirconium based metal-organic framework can adsorb perrhenate (ReO4-) anions, a non-radioactive sur-rogate for TcO4-, from water even in the presence of other common anions. Synchrotron based powder X-ray diffraction and molecular simulations were used to identify the position of the adsorbed ReO4- (surrogate for TcO4-) molecule within the framework.

Zirconium-Based Metal–Organic Framework for Removal of Perrhenate from Water

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Debasis; Xu, Wenqian; Nie, Zimin; Johnson, Lewis E. V.; Coghlan, Campbell; Sushko, Maria L.; Kim, Dongsang; Schweiger, Michael J.; Kruger, Albert A.; Doonan, Christian J.; Thallapally, Praveen K.

2016-09-06

Efficient removal of pertechnetate (TcO4 -) anions from liquid waste or melter off-gas solution for alternative treatment is one of the promising options to manage 99Tc in legacy nuclear waste. Safe immobilization of 99Tc is of major importance due to its long half-life (t1/2= 2.13 × 105 yrs) and environmental mobility. Different types of inorganic and solid state ion-exchange materials such as layered double hydroxides have been shown to absorb TcO4 - anions from water. However, both high capacity and selectivity have yet to be achieved in a single material. Herein, we show that a protonated version of an ultra-stable zirconium based metalorganic framework can adsorb perrhenate (ReO4 -) anions, a non-radioactive surrogate for TcO4 -, from water even in the presence of other common anions. Synchrotron based powder X-ray diffraction and molecular simulations were used to identify the position of the adsorbed ReO4 - (surrogate for TcO4 -) molecule within the framework.

Removal of radionuclides from household water; Metoder foer avlaegsnande av radionuklider fraan hushaallsvatten

Energy Technology Data Exchange (ETDEWEB)

Vesterbacka, P.; Turtiainen, T.; Haemaelaeinen, K.; Salonen, L.; Arvela, H.

2007-02-15

Research upon methods for removing radionuclides from household water was initiated in Finland in 1995. Three research projects, of which two were carried out with National Technology Agency of Finland and one with CEC, have been completed by the end of 2002. One of the main objectives of the research was to compose a guidebook for consumers and water treatment companies. Radon can be removed from household water by aeration and by activated carbon filtration. Aerators that are well designed and set up can remove over 90% of waterborne radon. The best aerators have achieved removal efficiencies that are nearly 100%. However, setting up an aeration system requires thorough planning. Also, activated carbon filtration removes radon efficiently. The removal efficiencies have been over 90%, often nearly 100%. Depending on the water quality and usage, the carbon batch inside the filter needs to be changed every 2 - 3 years. Since activated carbon filters emit gamma radiation while in use, they should not be installed inside the dwelling but in a separate building or by the well. It is recommended that uranium be removed from drinking water by anion exchange, which is the most efficient removal method for this purpose. Typically, the removal efficiencies are nearly 100%. The one exception is the so called tap filter, the removal efficiency of which depends on uranium concentration in raw water and the rate of water flow. High saline concentration in water may extricate uranium from ion exchange resin. Changes in plumbing pressure or pH-value do not have any significant influence in uranium retention. Removal efficiencies of lead and polonium vary a lot depending on the chemical form in which they occur in water. They can be reliably removed from water by reverse osmosis only. Other treatment methods, such as ion exchange and activated carbon filtration, remove lead and polonium partly. Lead and polonium are removed more efficiently when they are bound onto smaller

Removal of some radionuclides from water by bioaccumulation

Energy Technology Data Exchange (ETDEWEB)

Miskovic, D.; Conkic, L.; Dalmacija, B.; Gantar, M. (Trg D. Obradvica 3, Novi Sad (Yugoslavia). Faculty of Sciences)

1992-01-01

First objective of this study was to investigate the application of biologically activated carbon (BAC) as well as its comparison to adsorption, with the aim of removing some radionuclides from water. The isotopes Cs[sup 134] and Cs[sup 137] were bioaccumulated by BAC up to 50%, while the I[sup 131] isotope was only physicochemically adsorbed (about 40%). Also, the process of radionuclides (Cs[sup 137], Ce[sup 139], Co[sup 57], Co[sup 60]) fixation on blue-green algae (Nostoc sp.) was investigated. The kinetics of the removal of these radionuclides from water was recorded. It was found that after a contact period of about half an hour 40-70% of the activity was removed. (Author).

Implication of Crystal Water Molecules in Inhibitor Binding at ALR2 Active Site

Directory of Open Access Journals (Sweden)

Hymavati

2012-01-01

Full Text Available Water molecules play a crucial role in mediating the interaction between a ligand and a macromolecule. The solvent environment around such biomolecule controls their structure and plays important role in protein-ligand interactions. An understanding of the nature and role of these water molecules in the active site of a protein could greatly increase the efficiency of rational drug design approaches. We have performed the comparative crystal structure analysis of aldose reductase to understand the role of crystal water in protein-ligand interaction. Molecular dynamics simulation has shown the versatile nature of water molecules in bridge H bonding during interaction. Occupancy and life time of water molecules depend on the type of cocrystallized ligand present in the structure. The information may be useful in rational approach to customize the ligand, and thereby longer occupancy and life time for bridge H-bonding.

Oil and grease (O&G removal from commercial kitchen waste water using carbonised grass as a key media

Directory of Open Access Journals (Sweden)

Rahmat Siti Nazahiyah

2017-01-01

Full Text Available Oil and grease (O&G are usually found in kitchen waste water. O&G are poorly soluble in water and can cause serious problems during the wastewater treatment. Adsorption is a fundamental process in the treatment of kitchen waste water and very economical. Activated carbon is the most effective adsorbent for this application. Therefore, the aim of the current study is to determine the potential of four materials (i.e. sand, gravel, carbonised grass (CG and clay powder as filter media for O&G removal. The CGs were originated from “Elephant Grass” and it is a fast growing plant with significant potential as carbon. The clay acts as a magnet, drawing the oil molecules out of the water and causing them to attach to the surfaces of the clay. In the current study, two filters were developed with different media materials to get the best percentage removal. Filters 1 and 2 were filled with sand, gravel and CG, and sand, gravel, CG and powder clay, respectively. Three samples were taken during peak hour between April and May 2016. The initial O&G concentration varied from 101.37 mg/l to 248.30 mg/l and the final concentration varied from none to 22.57 mg/l for both filters. The percentage removal (% of O&G were between 90.9 and 97.3 (Filter 1 and between 94.3 and 100 (Filter 2. Overall, both filters could efficiently remove O&G in the waste water and the quality of the carbonised grass proved to be as good as carbon produced from other traditional sources.

The effectiveness of conventional water treatment in removing ...

African Journals Online (AJOL)

Algal blooms are a global problem due to various negative effects that can compromise water quality, such as the production of metabolites that are responsible for odour, colour, taste and toxins. In drinking water supplies algae can reduce the aesthetics of potable water when not readily removed by conventional water ...

Pore diffusion limits removal of monochloramine in treatment of swimming pool water using granular activated carbon.

Science.gov (United States)

Skibinski, Bertram; Götze, Christoph; Worch, Eckhard; Uhl, Wolfgang

2018-04-01

Overall apparent reaction rates for the removal of monochloramine (MCA) in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system and under conditions typical for swimming pool water treatment. Reaction rates dropped and quasi-stationary conditions were reached quickly. Diffusional mass transport in the pores was shown to be limiting the overall reaction rate. This was reflected consistently in the Thiele modulus, in the effect of temperature, pore size distribution and of grain size on the reaction rates. Pores <2.5 times the diameter of the monochloramine molecule were shown to be barely accessible for the monochloramine conversion reaction. GACs with a significant proportion of large mesopores were found to have the highest overall reactivity for monochloramine removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of natural radionuclides from drinking water from private wells in Finland

International Nuclear Information System (INIS)

Huikuri, Pia; Salonen, Laina; Turtiainen, Tuukka

1999-01-01

Removal of natural radionuclides is often necessary in Finland when household water is taken from a drilled well. Removal of radionuclides by various methods from Finnish groundwaters were studied in a EU-research project, TENAWA. The results indicated that radon can be removed very efficiently (up to 99%) by applying aeration or granular activated carbon (GAC) filtration. Uranium and radium were also removed (over 94%) by using strong base anion (SBA) and strong acid cation (SAC) resins. The capability of reverse osmosis (RO) equipment to remove radionuclides was over 90% for uranium, radium and polonium. The water quality analyses indicated that water quality remained mostly good during the water treatment. (au)

Removal of arsenic from potable water by adsorptive media treatment techniques

International Nuclear Information System (INIS)

Yousuf, S.; Khan, S.; Aslam, M.T.; Khan, A.R.

2012-01-01

Summary: This study was conducted to investigate the arsenic removal efficiency of different adsorptive media from water. Different naturally occurring materials such as bauxite, plastic clay, plaster of Paris, lime, alum, and alumina etc. were used for the development of media to remove arsenic As/sup +5/ present in the artificially contaminated water. Different ratios of the selected materials were combined and ignited at 9000 C to enhance its arsenic removing efficiency. It was found that the media bauxite, plastic clay, lime (1:1:1) has a maximum removal (99%) of As +5 species from aqueous media and can be used on- site to reduce the arsenic contamination of potable water. Furthermore, the materials used in this experiment were cheaply and abundantly available within the country. The method is very simple and economically viable, for removal of arsenic from potable water. (author)

Removal of trace metal contaminants from potable water by electrocoagulation

OpenAIRE

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

2016-01-01

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...

Nuclear reactor with makeup water assist from residual heat removal system

Science.gov (United States)

Corletti, Michael M.; Schulz, Terry L.

1993-01-01

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path.

Nuclear reactor with makeup water assist from residual heat removal system

International Nuclear Information System (INIS)

Corletti, M.M.; Schulz, T.L.

1993-01-01

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path. 2 figures

Nuclear reactor with makeup water assist from residual heat removal system

Science.gov (United States)

Corletti, M.M.; Schulz, T.L.

1993-12-07

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path. 2 figures.

Iron and manganese removal from drinking water

OpenAIRE

Pascu, Daniela-Elena; Neagu (Pascu), Mihaela; Alina Traistaru, Gina; Nechifor, Aurelia Cristina; Raluca Miron, Alexandra

2016-01-01

The purpose of the present study is to find a suitable method for removal of iron and manganese from ground water, considering both local economical and environmental aspects. Ground water is a highly important source of drinking water in Romania. Ground water is naturally pure from bacteria at a 25 m depth or more. However, solved metals may occur and if the levels are too high, the water is not drinkable. Different processes, such as electrochemical and combined electrochemical-adsorption m...

Study the properties of activated carbon and oxyhydroxide aluminum as sorbents for removal humic substances from natural waters

International Nuclear Information System (INIS)

Shiyan, L N; Machekhina, K I; Gryaznova, E N

2016-01-01

The present work relates to the problem of high-quality drinking water supply using processes of adsorption on activated carbon and aluminum oxyhydroxide for removal humic- type organic substances. Also the paper reports on sorbtion properties of the activeted carbon Norit SA UF and oxyhydroxide aluminum for removal humic substances. It was found out that the maximum adsorption capacity of activated carbon to organic substances is equal to 0.25 mg/mg and aluminum oxyhydroxide is equal to 0.3 mg/mg. It is shown that the maximum adsorption capacity of activated carbon Norit SA UF to iron (III) ions is equal to 0.0045 mg/mg and to silicon ions is equal to 0.024 mg/mg. Consequently, the aluminum oxyhydroxide has better adsorption characteristics in comparison with the activated carbon for removal of humic substances, iron and silicon ions. It is associated with the fact that activated carbon has a large adsorption surface, and this is due to its porous structure, but not all molecules can enter into these pores. Therefore, the fibrous structure of aluminum oxyhydroxide promotes better sorption capacity. The presented results suggest that activated carbon Norit SA UF and aluminum oxyhydroxide can be used as sorbents for removal humic substances or other organic substances from groundwater and natural waters. (paper)

Electrochemical filtration for turbidity removal in industrial cooling/process water systems

International Nuclear Information System (INIS)

Kumbhar, A.G.; Venkateswaran, G.

2008-01-01

Water samples of large cooling water reservoirs may look visibly clear and transparent, but still may contain sub-micron size particles at sub-parts-per-million levels. Deposition of these particles on heat exchanger surfaces, reduces the heat transfer efficiency in power industry. In nuclear power plants, additionally it creates radiation exposure problems due to activation of fine metallic turbidity in the reactor core and its subsequent transfer to out-of-core surfaces. Sub-micron filtration creates back high-pressure problem. Zeta filters available commercially are prescribed for separating either positively or negatively charged particles. They are of once-use and throw-type. Precipitation surface modified ion exchangers impart chemical impurities to the system. Thus, sub-micron size and dilute turbidity removal from large volumes of waters such as heat exchanger cooling water in nuclear and power industry poses a problem. Electro deposition of the turbidity causing particles, on porous carbon/graphite felt electrodes, is one of the best suited methods for turbidity removal from large volumes of water due to the filter's high permeability, inertness to the system and regenerability resulting in low waste generation. Initially, active indium turbidity removal from RAPS-1 heavy water moderator system, and microbes removal from heat exchanger cooling lake water of RAPS 1 and 2 were demonstrated with in-house designed and fabricated prototype electrochemical filter (ECF). Subsequently, a larger size, high flow filter was fabricated and deployed for iron turbidity removal from active process waters system of Kaiga Generation Station unit 1 and silica and iron turbidity removal from cooling water pond used for heat exchanger of a high temperature high pressure (HTHP) loop at WSCD, Kalpakkam. The ECF proved its exclusive utility for sub-micron size turbidity removal and microbes removal. ECF maneuverability with potential and current for both positively and

Alternative technology for arsenic removal from drinking water

Directory of Open Access Journals (Sweden)

Purenović Milovan

2007-01-01

Full Text Available Arsenic is a naturally occurring element in water, food and air. It is known as a poison, but in very small quantities it is showed to be an essential element. Actual problem in the world is arsenic removal from drinking water using modern and alternative technology, especially because EPA's and other international standards have reduced MCL from 50 to 10 ug/1. Because of rivers and lakes pollution, in a number of plants for natural water purification, average concentrations of arsenic in water are up to 100 ug/1. According to MCL, present technologies are unadjusted for safely arsenic removal for concentrations below of 10 ug/1. This fact has inspired many companies to solve this problem adequately, by using an alternative technologies and new process able materials. In this paper the observation of conventional and the alternative technologies will be given, bearing in mind complex chemistry and electrochemistry of arsenic, formation of colloidal arsenic, which causes the biggest problems in water purification technologies. In this paper many results will be presented, which are obtained using the alternative technologies, as well as the newest results of original author's investigations. Using new nanomaterials, on Pilot plant "VALETA H2O-92", concentration of arsenic was removed far below MLC value.

Treatment technology for removing radon from small community water supplies

International Nuclear Information System (INIS)

Kinner, N.E.; Quern, P.A.; Schell, G.S.; Lessard, C.E.; Clement, J.A.

1990-01-01

This paper reports on the selection of an appropriate treatment system to remove radon from drinking water which depends primarily upon percent removal; capital and operating and maintenance costs; safety; raw water quality with respect to parameters such as Fe, Mn, bacteria, and organics. The radon removal efficiency of the diffused bubble and packed tower aeration exceeded 99% at A:W ratios of 15:1 and 5:1, respectively; the GAC system averaged 81 ± 7.7%. Though our field evaluations indicated that GAC systems may not be as efficient as aeration systems, the system tested was operated above design requirements for most of the study period. Other researchers have found removals of greater than 99% with GAC point-of-entry applications. Therefore, each of these processes has the potential to consistently remove 99% of the radon applied. However, even this percent removal may not be sufficient to meet an MCL in the range of 200 to 1000 pCi/L if the raw water contained more than 20,000 to 100,000 pCi/L, respectively

Arsenic removal in water by means of coagulation-flocculation processes

International Nuclear Information System (INIS)

Franco, M. F.; Carro P, M. E.

2014-01-01

Arsenic and arsenical compounds are considered as carcinogenic and risky for humans according to epidemiological evidence related with the ingestion of arsenical water during a long period. In many places the only source of drinking water contains arsenic and, therefore, removal strategies have to be investigated. This work shows experimental results of coagulation-flocculation processes implemented to evaluate the efficiency in the removal of arsenic from drinking water. The main objectives include the evaluation of the relevant aspect that controls the removal efficiency. Experimental tests were performed with coagulant concentrations from 5 to 500 mg/L, solid particle concentrations from 0 to 6000 mg/L, and initial arsenic concentrations from 0.5 to 5 mg/L. These variables were simultaneously varied in more than 100 experiments. The efficiency in remediation ranged from 0% to 95%. Removal efficiency near 95% was obtained when using ferric chloride as coagulant, and was close to 80% when using aluminium sulfate as coagulant in arsenate solutions. The remediation efficiency decreased significantly when the ferric chloride concentration was higher than 50 mg/L in relation to the obtained results for aluminum sulfate for different type and concentration of soil particles. The highest removal efficiency were obtained at ph between 3 and 5 in oxidized solutions. Obtained results simulated by means of multiple linear regression analysis (R>0.90) allow determining that the main parameters that control the removal of arsenic from drinking water are coagulant concentration, ph, and solid particles concentration. Conversely, particle mineralogy and coagulant type have less significant effect on the removal by means of coagulation-flocculation mechanisms. Obtained results are relevant for the removal of As in water treatment plants as well as for the development of small scale filters. The samples were studied by scanning electron microscopy and energy dispersive X

Naturally occurring radionuclides in drinking water before and after radon removal

International Nuclear Information System (INIS)

Swedjemark, G.A.; Linden, A.

1998-06-01

Radon removal can, with a good effect, be used to remove radon from well water. The short-lived radon progeny have been investigated in the raw and cleaned water from six private wells where radon removal based on aeration and recirculation of the water have been installed. The results from this pilot study indicate that the short-lived radon progeny in some cases follow the water to the tap for consumption to such an extent that the problem should be considered. The extent of the study is not sufficient for general conclusions. However, it is important to stress that the effective dose from the short-lived progeny is always lower than it would have been from the radon, when no radon is removed

Removal method of radium in mine water by filter sand

International Nuclear Information System (INIS)

Taki, Tomihiro; Naganuma, Masaki

2003-01-01

Trace radium is contained in mine water from the old mine road in Ningyo-Toge Environmental Engineering Center, JNC. We observed that filter sand with hydrated manganese oxide adsorbed radium in the mine water safely for long time. The removal method of radium by filter sand cladding with hydrated manganese oxide was studied. The results showed that radium was removed continuously and last for a long time from mine water with sodium hypochlorite solution by passing through the filter sand cladding with hydrated manganese. Only sodium hypochlorite solution was used. When excess of it was added, residue chlorine was used as chlorine disinfection. Filter sand cladding with hydrated manganese on the market can remove radium in the mine water. The removal efficiency of radium is the same as the radium coprecipitation method added with barium chloride. The cost is much lower than the ordinary methods. Amount of waste decreased to about 1/20 of the coprecipitation method. (S.Y.)

Community Responses to the Removal of Bottled Water on a University Campus

Science.gov (United States)

Mikhailovich, Katja; Fitzgerald, Robert

2014-01-01

Purpose: This paper aimed to examine the impact of the removal of bottled water on the campus community. This paper presents the findings of a survey conducted at the first Australian university to remove single-use bottled water from sale on a small regional university campus. The removal of bottled water from sale at the university formed part…

Effectiveness of table top water pitcher filters to remove arsenic from drinking water.

Science.gov (United States)

Barnaby, Roxanna; Liefeld, Amanda; Jackson, Brian P; Hampton, Thomas H; Stanton, Bruce A

2017-10-01

Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As 3+ and As 5+ , from 1000μg/L to water and its use reduces plastic waste associated with bottled water. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Removal of arsenic from ground water samples collected from West Bengal, India

International Nuclear Information System (INIS)

Ajith, Nicy; Swain, K.K.; Dalvi, Aditi A.; Verma, R.

2015-01-01

Arsenic contamination in ground water is one of the major concerns in many parts of the world including Bangladesh and India. Considering the high toxicity of arsenic, World Health Organization (WHO) has set a provisional guideline value of 10 μg L -1 for arsenic in drinking water. Several methods have been adopted for the removal of arsenic from drinking water. Most of the methods fail to remove As(III), the most toxic form of arsenic. An extra oxidative treatment step is essential for effective removal of total arsenic. Manganese dioxide (MnO 2 ) oxidizes As(III) to As(V). Removal of arsenic from water using manganese dioxide has been reported. During this work, removal of arsenic from ground water samples collected from arsenic contaminated area of West Bengal, India were carried out using MnO 2

Influence of orientation averaging on the anisotropy of thermal neutrons scattering on water molecules

International Nuclear Information System (INIS)

Markovic, M. I.; Radunovic, J. B.

1976-01-01

Determination of spatial distribution of neutron flux in water, most frequently used moderator in thermal reactors, demands microscopic scattering kernels dependence on cosine of thermal neutrons scattering angle when solving the Boltzmann equation. Since spatial orientation of water molecules influences this dependence it is necessary to perform orientation averaging or rotation-vibrational intermediate scattering function for water molecules. The calculations described in this paper and the obtained results showed that methods of orientation averaging do not influence the anisotropy of thermal neutrons scattering on water molecules, but do influence the inelastic scattering

Cyclic process of simazine removal from waters by adsorption on zeolite H-Y and its regeneration by thermal treatment

Energy Technology Data Exchange (ETDEWEB)

Sannino, Filomena, E-mail: fsannino@unina.it [Dipartimento di Scienze del Suolo, della Pianta, dell' Ambiente e delle Produzioni Animali, Universita di Napoli ' Federico II' , Via Universita 100, 80055 Portici (Italy); Ruocco, Silvia [Dipartimento di Scienze del Suolo, della Pianta, dell' Ambiente e delle Produzioni Animali, Universita di Napoli ' Federico II' , Via Universita 100, 80055 Portici (Italy); Marocco, Antonello; Esposito, Serena; Pansini, Michele [Laboratorio Materiali - Dipartimento di Meccanica, Strutture, Ambiente e Territorio - Universita di Cassino - Via Di Biasio 43 - 03043 Cassino (Italy)

2012-08-30

Highlights: Black-Right-Pointing-Pointer Bringing agrochemical concentration below the law limit allowed in wastewaters. Black-Right-Pointing-Pointer Regenerating the adsorbent which can be used again in the cyclic process. Black-Right-Pointing-Pointer Destroying the agrochemical molecules by combustion. - Abstract: Removal of the agrochemical simazine from polluted waters through adsorption by zeolite Y in its protonic form was studied. The investigated parameters were: pH, time, initial simazine concentration and solid/liquid ratio. An iterative process of simazine removal from waters is proposed, featuring: (i) final agrochemical concentration well below 0.05 mg/dm{sup 3}, the maximum concentration allowed by Italian laws in wastewaters; (ii) regeneration of the adsorbent by a few minutes thermal treatment in air at about 500 Degree-Sign C, which results in the combustion of simazine without damage of the adsorbent; (iii) destruction of the agrochemical compound by combustion.

40 CFR 1065.659 - Removed water correction.

Science.gov (United States)

2010-07-01

... water content according to paragraph (b)(1) of this section. (3) You may also use a nominal value of...) Use any of the techniques described in paragraph (b) of this section. (2) If the measurement comes.... (a) If you remove water upstream of a concentration measurement, x, or upstream of a flow measurement...

Preozonation Effect on Total Organic Carbon Removal in Surface Water Treatment

Directory of Open Access Journals (Sweden)

Ali Torabian

2006-06-01

Full Text Available In drinking water treatment, preozonation is often applied in order to control the microorganisms and taste and odor causing materials, which may influence organics removal by preoxidation and adsorption. Using commercial and natural water humic substances, the positive effect of preozonation as an aid to coagulation-flocculation of these compounds was confirmed by removal of TOC removal in Tehranpars Water Treatment Plant in Tehran. These experiments were conducted as bench-scale studies through a series of jar tests using different pH coagulant dosages and total organic carbon concentration of approximately 4, 8 and 12 mg/L. In addition to TOC removal, the existence of an optimum preozonation dose (OPZD was also confirmed. Experiments show that preozonation can improve coagulation and flocculation depending on influent TOC concentration of raw water. The results demonstrate different effects of preozonation on removal of influent TOC. Preozonation showed a positive effect on a system with low influent TOC and very low molecular weight (noncolloidal humic substances.

Treatment technology for removing radon from small community water supplies

International Nuclear Information System (INIS)

Kinner, N.E.; Quern, P.A.; Schell, G.S.; Lessard, C.E.; Clement, J.A.

1989-01-01

Radon contamination of drinking water primarily affects individual homeowners and small communities using ground-water supplies. Presently, three types of treatment processes have been used to remove radon: granular activated carbon adsorption (GAC), diffused-bubble aeration, and packed-tower aeration. In order to obtain data on these treatment alternatives for small communities water supplies, a field evaluation study was conducted on these three processes as well as on several modifications to aeration of water in storage tanks considered to be low cost/low technology alternatives. The paper presents the results of these field studies conducted at a small mobile home park in rural New Hampshire. The conclusion of the study was that the selection of the appropriate treatment system to remove radon from drinking water depends primarily upon: (1) precent removal of process; (2) capital operating and maintenance costs; (3) safety (radiation); and (4) raw water quality (Fe, Mn, bacteria and organics)

Removing Dissolved Silica from Waste Water with Catechol and Active Carbon

Energy Technology Data Exchange (ETDEWEB)

Sasan, Koroush [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanoscale Sciences Dept.; Brady, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Energy Program; Krumhansl, James L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geosciences Dept.; Nenoff, Tina M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Physical Chemical and Nano Sciences Center

2017-01-01

Fresh water scarcity is going to be a global great challenge in the near future because of the increasing population. Our water resources are limited and, hence, water treatment and recycling methods are the only alternatives for fresh water procurement in the upcoming decades. Water treatment and recycling methods serve to remove harmful or problematic constituents from ground, surface and waste waters prior to its consumption, industrial supply, or other uses. Scale formation in industrial and domestic installations is still an important problem during water treatment. In water treatment, silica scaling is a real and constant concern for plant operations. The focus of this study is on the viability of using a combination of catechol and active carbon to remove dissolved silica from concentrated cooling tower water (CCTW). Various analytical methods, such as ICP-MS and UV-vis, were used to understand the structure-property relationship between the material and the silica removal results. UV-Vis indicates that catechol can react with silica ions and form a silica-catecholate complex. The speciation calculation of catechol and silica shows that catechol and silica bind in the pH range of 8 – 10; there is no evidence of linkage between them in neutral and acidic pHs. The silica removal results indicate that using ~4g/L of catechol and 10g/L active carbon removes up to 50% of the dissolved silica from the CCTW.

Removal of different fractions of NOM foulants during demineralized water backwashing

KAUST Repository

Li, Sheng

2012-09-01

The effectiveness of demineralized water backwashing on fouling by different fractions of NOM was investigated in this study. Two types of natural surface water (Schie canal and Biesbosch reservoir) were tested to confirm the improvement of demineralized water backwashing on fouling control, and LC-OCD analysis was conducted on Schie canal water to find out which fraction of NOM was removed with those backwashes. Results derived from natural waters showed that demineralized water backwashing substantially improved UF fouling control. LC-OCD analyses showed both UF permeate and demineralized water backwashes were effective on removing part of biopolymers, but demineralized water is also effective for humic substances and a limited amount of low molecular weight substances. However, based on the LC-OCD results, even demineralized water backwashing is not effective to remove all humic substances and biopolymers rejected on the UF membranes. © 2012 Elsevier B.V. All rights reserved.

An innovative bovine odorant binding protein-based filtering cartridge for the removal of triazine herbicides from water.

Science.gov (United States)

Bianchi, Federica; Basini, Giuseppina; Grolli, Stefano; Conti, Virna; Bianchi, Francesco; Grasselli, Francesca; Careri, Maria; Ramoni, Roberto

2013-01-01

Odorant binding protein (OBP) is a multi-functional scavenger for small hydrophobic molecules dissolved in the mucus lining the nasal epithelia of mammals, characterized by broad ligand binding specificity towards a large number of structurally unrelated natural and synthetic molecules of different chemical classes. Here, we demonstrate for the first time the application of OBP as the active element of an innovative filtering matrix for the removal of environmental pollutants such as triazine herbicides from water samples. The filtering device, obtained by coupling histidine-tagged bovine OBP to a nickel nitrilotriacetic acid (Ni-NTA) agarose resin, was characterized in terms of retention capacity for the herbicides atrazine, simazine, and propazine. Analysis of these herbicides at trace levels with solid-phase microextraction followed by gas chromatography-mass spectrometry using the selected ion monitoring mode proved the capabilities of the proposed device for the decontamination of surface and groundwater samples in the 0.2-2,300 μg/L concentration range, obtaining a reduction in the triazine content greater than 97 %, thus suggesting its possible use for the potabilization of water.

PHOSPHATES REMOVAL FROM REJECT WATER FROM DIGESTION OF SLUDGE

Directory of Open Access Journals (Sweden)

Elżbieta Sperczyńska

2016-06-01

Full Text Available The aim of the research work was to evaluate if coagulants used on technical scale are useful in phosphates removal from reject water. Effectiveness of phosphorus compounds removal from reject water from digestion of sewage sludge was examined. Selected prehydrolysed alkaline aluminium polychlorides were used. The results were compared to the ones obtained with aluminium sulphate. Reject water from digestion of sewage sludge form WWTP of 100 000 PE were examined. Commercial agents – prehydrolysed PAX 18, PAX XL10, PAX-XL1905 as well as aluminium sulphate were used. Various doses of coagulants: 0.7; 1.0; 1.5 – time higher than stoichiometric dose were applied. Stoichiometric dose was calculated based on chemical reaction of insoluble aluminium phosphate formation. Concentrations of Kiejdahl nitrogen (891 mgNKj/dm3, phosphates (125 mgPO43-/dm3 and organic compounds - COD (592 mgO2/dm3 in reject water were very high. The effectiveness of coagulation process increased as the doses of chemical agents increased. The most effective doses were the highest ones used during the experiment. The most effective agent was PAX 18 (96% removal efficiency. As the phosphates concentration decreased COD content declined simultaneously. Maximum COD removal (47% was obtained when highly alkaline PAX XL 1905 was used. Use of the lowest dose of Al2(SO43 allowed for 50% phosphates removal, whereas the lowest dose of PAX 18 decreased phosphates concentration by 83%.

Winter Maintenance Wash-Water Heavy Metal Removal Pilot Scale Evaluation

Directory of Open Access Journals (Sweden)

Christopher M. Miller

2016-01-01

Full Text Available To encourage sustainable engineering practices, departments of transportation are interested in reusing winter maintenance truck wash water as part of their brine production and future road application. Traffic-related metals in the wash water, however, could limit this option. The objective of this work was to conduct a pilot scale evaluation of heavy metal (copper, zinc, iron, and lead removal in a filtration unit (maximum flow rate of 45 L/minute containing proprietary (MAR Systems Sorbster® media. Three different trials were conducted and approximately 10,000 L of wash water collected from a winter maintenance facility in Ohio was treated with the pilot unit. Lab studies were also performed on six wash-water samples from multiple facilities to assess particle size removal and estimate settling time as a potential removal mechanism during wash-water storage. Pilot unit total metal removal efficiencies were 79%, 77%, 63%, and 94% for copper, zinc, iron, and lead, respectively. Particle settling calculation estimates for copper and zinc show that 10 hours in storage can also effectively reduce heavy metal concentrations in winter maintenance wash water in excess of 70%. These pilot scale results show promise for reducing heavy metal concentrations to an acceptable level for reuse.

Nanoparticle Zere-valent Iron Affect on As (V Removal from Drinking Water

Directory of Open Access Journals (Sweden)

Hamed Koohpayehzadeh

2012-10-01

Full Text Available Arsenic which is present in the underground and surface water is one of the most toxic elements threating human health and animals. Arsenic has been removed in different type of ways. In this study Arsenic removal from drinking water and its decreasing rates were investigated by NZVI (nanoparticle zerovalent iron to standard limit (I.e.  0.01 mg/lit . The tests were conducted on reactor containing 100 ml water containing 1mg/L. Arsenic by virtue of Batch method. The mixture was executed in mixing was done an Oultrasnic device in order to have better mixture and complete distribution of nanoparticles in water. Then the arsenic was removed from the water by VATMAN paper of 0.45 Hm. The remained arsenic in the water was measured by ICP device. In this article the influence of the parameters including mixture time , PH ,NZVI and arcenic doses were examined . Having perfomed many tests the results showed that 1 mg arsenic can be removed 100 percent by 0.05 g NZVI in 8 min. It is possible to remove by 98 percent arsenic in 5-10 PH range. Iron nanopaticle way is an effective and rapid way to remove arsenic from water and various conditions have not considerable effect on it.

Colloids removal from water resources using natural coagulant: Acacia auriculiformis

Science.gov (United States)

Abdullah, M.; Roslan, A.; Kamarulzaman, M. F. H.; Erat, M. M.

2017-09-01

All waters, especially surface waters contain dissolved, suspended particles and/or inorganic matter, as well as several biological organisms, such as bacteria, algae or viruses. This material must be removed because it can affect the water quality that can cause turbidity and colour. The objective of this study is to develop water treatment process from Seri Alam (Johor, Malaysia) lake water resources by using natural coagulant Acacia auriculiformis pods through a jar test experiment. Jar test is designed to show the effectiveness of the water treatment. This process is a laboratory procedure that will simulate coagulation/flocculation with several parameters selected namely contact time, coagulant dosage and agitation speed. The most optimum percentage of colloids removal for each parameter is determined at 0.2 g, 90 min and 80 rpm. FESEM (Field-emission Scanning Electron Microscope) observed the small structures of final floc particles for optimum parameter in this study to show that the colloids coagulated the coagulant. All result showed that the Acacia auriculiformis pods can be a very efficient coagulant in removing colloids from water.

Enteric virus removal from water by coal-based sorbents: development of low-cost water filters

Energy Technology Data Exchange (ETDEWEB)

Chaudhuri, M.; Sattar, S.A.

1986-01-01

Using poliovirus type 1 (Sabin) and dechlorinated tap water, several coal-based sorbents were tested for their capacity to remove viruses from water. The sorbents included bituminous coal from Giridih, India, pretreated/impregnated with either alum, ferric hydroxide, lime or manganese dioxide. Filtrasorb-400, commercially available active carbon, was used as a reference. In batch tests, with input virus concentration of 2.34-2.83x10/sup 6/ PFU/1 and sorbent concentration of 10 g/l, alum pretreated coal removed about 96% of the virus when pH of the water was between 6.3 and 8.9. Virus sorption was rapid and a plateau was reached in 30 min. Compared with the active carbon, alum pretreated coal exhibited greater sorption energy and about one log higher limiting poliovirus sorption capacity. Downflow column study indicated the potential of alum pretreated coal as a filter media for removing enteric viruses from water. A previous study showed this sorbent to be capable of removing enteric bacteria as well. Water filters prepared from such low-cost material may prove useful for domestic use in rural areas of India and other developing countries. 19 refs.

REDUCING ARSENIC LEVELS IN DRINKING WATER DURING IRON REMOVAL PROCESSES

Science.gov (United States)

The presentation provides an overview of iron removal technology for the removal of arsenic from drinking water. The presentation is divided into several topic topics: Arsenic Chemistry, Treatment Selection, Treatment Options, Case Studies and Iron Removal Processes. Each topic i...

Investigation of the Hydantoin Monomer and its Interaction with Water Molecules

Science.gov (United States)

Gruet, Sébastien; Perez, Cristobal; Schnell, Melanie

2017-06-01

Hydantoin (Imidazolidine-2,4-dione, C_3H_4N_2O_2) is a five-membered heterocyclic compound of astrobiological interest. This molecule has been detected in carbonaceous chondrites [1], and its formation can rise from the presence of glycolic acid and urea, two prebiotic molecules [2]. The hydrolysis of hydantoin under acidic conditions can also produce glycine [3], an amino acid actively searched for in the interstellar medium. Spectroscopic data of hydantoin is very limited and mostly dedicated to the solid phase. The high resolution study in gas phase is restricted to the work recently published by Ozeki et al. reporting the pure rotational spectra of the ground state and two vibrational states of the molecule in the millimeter-wave region (90-370 GHz)[4]. Using chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy, we recorded the jet-cooled rotational spectra of hydantoin with water between 2 to 8 GHz. We observed the ground state of hydantoin monomer and several water complexes with one or two water molecules. All the observed species exhibit a hyperfine structure due to the two nitrogen atoms present in the molecule, which were fully resolved and analyzed. Additional experiments with a ^{18}O enriched water sample were realized to determine the oxygen-atom positions of the water monomers. These experiments yielded accurate structural information on the preferred water binding sites. The observed complexes and the interactions that hold them together, mainly strong directional hydrogen bonds, will be presented and discussed. [1] Shimoyama, A. and Ogasawara, R., Orig. Life Evol. Biosph., 32, 165-179, 2002. DOI:10.1023/A:1016015319112. [2] Menor-Salván, C. and Marín-Yaseli, M.R., Chem. Soc. Rev., 41(16), 5404-5415, 2012. DOI:10.1039/c2cs35060b. [3] De Marcellus P., Bertrand M., Nuevo M., Westall F. and Le Sergeant d'Hendecourt L., Astrobiology. 11(9), 847-854, 2011. DOI:10.1089/ast.2011.0677. [4] Ozeki, H., Miyahara R., Ihara H., Todaka S., Kobayashi

Preparation and characterisation of core-shell CNTs@MIPs nanocomposites and selective removal of estrone from water samples.

Science.gov (United States)

Gao, Ruixia; Su, Xiaoqian; He, Xiwen; Chen, Langxing; Zhang, Yukui

2011-01-15

This paper reports the preparation of carbon nanotubes (CNTs) functionalized with molecularly imprinted polymers (MIPs) for advanced removal of estrone. CNTs@Est-MIPs nanocomposites with a well-defined core-shell structure were obtained using a semi-covalent imprinting strategy, which employed a thermally reversible covalent bond at the surface of silica-coated CNTs for a large-scale production. The morphology and structure of the products were characterised by transmission electron microscopy and Fourier transform infrared spectroscopy. The adsorption properties were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The results demonstrate that the imprinted nanocomposites possess favourable selectivity, high capacity and fast kinetics for template molecule uptake, yielding an adsorption capacity of 113.5 μmol/g. The synthetic process is quite simple, and the different batches of synthesized CNTs@Est-MIPs nanocomposites showed good reproducibility in template binding. The feasibility of removing estrogenic compounds from environmental water using the CNTs@Est-MIPs nanocomposites was demonstrated using water samples spiked with estrone. Copyright © 2010 Elsevier B.V. All rights reserved.

Tests of some methods to remove I-131 from contaminated tap water

International Nuclear Information System (INIS)

Tagami, Keiko; Uchida, Shigeo

2011-01-01

Following the Fukushima Daiichi Nuclear Power Plant accident, iodine-131 concentrations in tap water higher than 100 Bq L"-"1 were reported by several local governments in the Kanto Plain in March 2011. To remove iodine-131 from tap water, five methods were tested in this study, that is, (1) boiling, (2) adding charcoals from oak or bamboo, (3) activated charcoals, (4) water purifiers, and (5) reverse osmosis (RO) treatments. Boiling was shown to be not effective in removing iodine-131 from tap water; indeed even higher concentrations may result from the liquid-volume reduction accompanying this process. Adding charcoals and activated charcoal treatment could not remove iodine-131, because no reduction of iodine-131 was observed in tap water samples after these treatments. Only limited effect was found with water purifiers with first several portions; no effect was expected with further water treatment. On the other hand, the RO showed high iodine-131 removal percentage of more than 95%, although the method needs about 5-10 L water to obtain 1 L of RO treated water. (author)

Evaluation of the Efficiency of Clay Pots in Removal of Water Impurities

Directory of Open Access Journals (Sweden)

K Naddafi , AH Mahvi, S Nasseri, M Mokhtari, H Zeraati

2005-04-01

Full Text Available Recently, inexpensive technologies for drinking water supply in small communities are highly considered in developing countries. One of these technologies is the application of ceramic filters that are usually made of diatomaceous earth or clay soil. This research was carried out to determine the efficiency of clay pots (as a filter in removing water impurities. Pilot and the related clay parts were manufactured and its efficiency in removing TDS, hardness, NO3-, color and turbidity was measured by passing water through the clay pipes. The results showed that the clay filters had not the potential to remove hardness, EC, TDS and nitrate of water. However, they showed excellent efficiency in turbidity removal (≥ 90% and could significantly decrease the color of the water (≥ 60%.

Femtosecond spectroscopic study of the solvation of amphiphilic molecules by water

NARCIS (Netherlands)

Rezus, Y.L.A.; Bakker, H.J.

2008-01-01

We use polarization-resolved mid-infrared pump-probe spectroscopy to study the aqueous solvation of proline and N-methylacetamide. These molecules serve as models to study the solvation of proteins. We monitor the orientational dynamics of partly deuterated water molecules (HDO) that are present at

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

Removal of Fe(II) from tap water by electrocoagulation technique

International Nuclear Information System (INIS)

Ghosh, D.; Solanki, H.; Purkait, M.K.

2008-01-01

Electrocoagulation (EC) is a promising electrochemical technique for water treatment. In this work electrocoagulation (with aluminum as electrodes) was studied for iron Fe(II) removal from aqueous medium. Different concentration of Fe(II) solution in tap water was considered for the experiment. During EC process, various amorphous aluminum hydroxides complexes with high sorption capacity were formed. The removal of Fe(II) was consisted of two principal steps; (a) oxidation of Fe(II) to Fe(III) and (b) subsequent removal of Fe(III) by the freshly formed aluminum hydroxides complexes by adsorption/surface complexation followed by precipitation. Experiments were carried out with different current densities ranging from 0.01 to 0.04 A/m 2 . It was observed that the removal of Fe(II) increases with current densities. Inter electrode distance was varied from 0.005 to 0.02 m and was found that least inter electrode distance is suitable in order to achieve higher Fe(II) removal. Other parameters such as conductivity, pH and salt concentration were kept constant as per tap water quality. Satisfactory iron removal of around 99.2% was obtained at the end of 35 min of operation from the initial concentration of 25 mg/L Fe(II). Iron concentration in the solution was determined using Atomic absorption spectrophotometer. By products obtained from the electrocoagulation bath were analyzed by SEM image and corresponding elemental analysis (EDAX). Cost estimation for the electrocoagulation was adopted and explained well. Up to 15 mg/L of initial Fe(II) concentration, the optimum total cost was 6.05 US$/m 3 . The EC process for removing Fe(II) from tap water is expected to be adaptable for household use

Water hyacinths and alligator weeds for removal of silver, cobalt, and strontium from polluted waters

Science.gov (United States)

Wolverton, B. C.; Mcdonald, R. C.

1975-01-01

Water hyacinths and alligator weeds demonstrated the ability to rapidly remove heavy metals from an aqueous system by root absorption and concentration. Water hyacinths demonstrated the ability to remove 0.439 mg of silver, 0.568 mg of cobalt, and 0.544 mg of strontium in an ionized form per gram of dry plant material in a 24-hour period. Alligator weeds removed a maximum of 0.439 mg of silver, 0.130 mg of cobalt, and 0.161 mg of strontium per gram of dry plant material per day.

Photoionization of water molecules by high energy photons

Directory of Open Access Journals (Sweden)

Lara Martini

2017-07-01

Full Text Available We theoretically study the photoionization of water molecules by high energy photon impact. We develop a model in which the final state wavefunction is given by a Coulomb continuum wavefunction with effective charges and the water molecule bound states are represented using the Moccia's monocentric wavefunctions. We obtain analytical expressions for the transition matrix element that enable the computation of cross sections by numerical quadratures. We compare our predictions for photon energies between 20 and 300 eV with more elaborated theoretical results and experiments. We obtain a very good agreement with experiments, in particular, at enough high energies where there is a lack of elaborated results due to their high computational cost. Received: 15 March 2017, Accepted: 25 June 2017; Edited by: S. Kais; DOI: http://dx.doi.org/10.4279/PIP.090006 Cite as: L Martini, D I R Boll, O A Fojón, Papers in Physics 9, 090006 (2017

Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water.

Science.gov (United States)

Carey, Manus; Jiujin, Xiao; Gomes Farias, Júlia; Meharg, Andrew A

2015-01-01

A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (Asi) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more Asi removed by cooking, suggesting that the Asi in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in Asi, or Asi free. This has the advantage of not only exposing grain to large volumes of cooking water, but also physically removes any Asi leached from the grain into the water receiving vessel. The relationship between cooking water volume and Asi removal in conventional rice cooking was demonstrated for the rice types under study. At a water-to-rice cooking ratio of 12:1, 57±5% of Asi could be removed, average of 6 wholegrain and 6 polished rice samples. Two types of percolating technology were tested, one where the cooking water was recycled through condensing boiling water steam and passing the freshly distilled hot water through the grain in a laboratory setting, and one where tap water was used to cook the rice held in an off-the-shelf coffee percolator in a domestic setting. Both approaches proved highly effective in removing Asi from the cooking rice, with up to 85% of Asi removed from individual rice types. For the recycled water experiment 59±8% and 69±10% of Asi was removed, on average, compared to uncooked rice for polished (n=27) and wholegrain (n=13) rice, respectively. For coffee percolation there was no difference between wholegrain and polished rice, and the effectiveness of Asi removal was 49±7% across 6 wholegrain and 6 polished rice samples. The manuscript explores the potential applications and further optimization of this percolating cooking water, high Asi removal, discovery.

Applicability of MIEX(®)DOC process for organics removal from NOM laden water.

Science.gov (United States)

Karpinska, Anna M; Boaventura, Rui A R; Vilar, Vítor J P; Bilyk, Andrzej; Molczan, Marek

2013-06-01

The aim of this study was to evaluate applicability of ion exchange process for organics removal from Douro River surface water at the intake of Lever water treatment plant using magnetized ion exchange resin MIEX®. Qualitative analysis of the natural organic matter present in the surface water and prediction of its amenability to removal in conventional coagulation process were assessed. Results obtained in MIEX®DOC process kinetic batch experiments allowed determination of ion exchange efficiency in dissolved organic carbon (DOC), UV absorbing organics, and true color removal. The data were compared with the efficiencies of the conventional unit processes for organics removal at Lever WTP. MIEX®DOC process revealed to be more efficient in DOC removal than conventional treatment achieving the efficiencies in the range of 61-91 %, lowering disinfection by-products formation potential of the water. DOC removal efficiency at Lever WTP depends largely on the raw water quality and ranges from 28 % for water of moderated quality to 89 % of significantly deteriorated quality. In this work, MIEX®DOC process was also used as a reference method for the determination of contribution of anionic fraction to dissolved organic matter and selectivity of the unit processes at Lever WTP for its removal.

Removal of Fe(II) from tap water by electrocoagulation technique

Energy Technology Data Exchange (ETDEWEB)

Ghosh, D.; Solanki, H. [Department of Chemical Engineering, Indian Institute of Technology, Guwahati 781039 (India); Purkait, M.K. [Department of Chemical Engineering, Indian Institute of Technology, Guwahati 781039 (India)], E-mail: mihir@iitg.ernet.in

2008-06-30

Electrocoagulation (EC) is a promising electrochemical technique for water treatment. In this work electrocoagulation (with aluminum as electrodes) was studied for iron Fe(II) removal from aqueous medium. Different concentration of Fe(II) solution in tap water was considered for the experiment. During EC process, various amorphous aluminum hydroxides complexes with high sorption capacity were formed. The removal of Fe(II) was consisted of two principal steps; (a) oxidation of Fe(II) to Fe(III) and (b) subsequent removal of Fe(III) by the freshly formed aluminum hydroxides complexes by adsorption/surface complexation followed by precipitation. Experiments were carried out with different current densities ranging from 0.01 to 0.04 A/m{sup 2}. It was observed that the removal of Fe(II) increases with current densities. Inter electrode distance was varied from 0.005 to 0.02 m and was found that least inter electrode distance is suitable in order to achieve higher Fe(II) removal. Other parameters such as conductivity, pH and salt concentration were kept constant as per tap water quality. Satisfactory iron removal of around 99.2% was obtained at the end of 35 min of operation from the initial concentration of 25 mg/L Fe(II). Iron concentration in the solution was determined using Atomic absorption spectrophotometer. By products obtained from the electrocoagulation bath were analyzed by SEM image and corresponding elemental analysis (EDAX). Cost estimation for the electrocoagulation was adopted and explained well. Up to 15 mg/L of initial Fe(II) concentration, the optimum total cost was 6.05 US$/m{sup 3}. The EC process for removing Fe(II) from tap water is expected to be adaptable for household use.

Organically modified clay removes oil from water

International Nuclear Information System (INIS)

Alther, G.R.

1995-01-01

When bentonite or other clays and zeolite are modified with quaternary amines, they become organophilic. Such modified bentonites are used to remove mechanically emulsified oil and grease, and other sparingly soluble organics. Types of oil found in water can include fats, lubricants, cutting fluids, heavy hydrocarbons such as tars, grease, crude oil, diesel oils; and light hydrocarbons such as kerosene, jet fuel, and gasoline. If the organoclay is granulated, it is placed into a liquid phase carbon filter vessel to remove FOGs (Free Oil and Grease) and chlorinated hydrocarbons. In this application the clay is mixed with anthrazite to prevent early plugging of the filter by oil or grease droplets. In batch systems a powdered organoclay is employed. Organoclay removes mechanically emulsified oil and grease at 5--7 times the rate of activated carbon, or 50% of its dry weight. Oil and grease and other large sparingly soluble chlorinated hydrocarbons and NOMs (Natural Organic Matter) blind the pores of activated carbon (and ion-exchange resins), reducing its effectiveness significantly. It is therefore economically advantageous for the end user to prepolish the water before it enters carbon vessels. Operating costs can often be reduced by 50% or more

Arsenic removal from water using iron-coated seaweeds.

Science.gov (United States)

Vieira, Bárbara R C; Pintor, Ariana M A; Boaventura, Rui A R; Botelho, Cidália M S; Santos, Sílvia C R

2017-05-01

Arsenic is a semi-metal element that can enter in water bodies and drinking water supplies from natural deposits and from mining, industrial and agricultural practices. The aim of the present work was to propose an alternative process for removing As from water, based on adsorption on a brown seaweed (Sargassum muticum), after a simple and inexpensive treatment: coating with iron-oxy (hydroxides). Adsorption equilibrium and kinetics were studied and modeled in terms of As oxidation state (III and V), pH and initial adsorbate concentration. Maximum adsorption capacities of 4.2 mg/g and 7.3 mg/g were obtained at pH 7 and 20 °C for arsenite and arsenate, respectively. When arsenite was used as adsorbate, experimental evidences pointed to the occurrence of redox reactions involving As(III) oxidation to As(V) and Fe(III) reduction to Fe(II), with As(V) uptake by the adsorbent. The proposed adsorption mechanism was then based on the assumption that arsenate was the adsorbed arsenic species. The most relevant drawback found in the present work was the considerable leaching of iron to the solution. Arsenite removal from a mining-influenced water by adsorption plus precipitation was studied and compared to a traditional process of coagulation/flocculation. Both kinds of treatment provided practically 100% of arsenite removal from the contaminated water, leading at best in 12.9 μg/L As after the adsorption and precipitation assays and 14.2 μg/L after the coagulation/flocculation process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Water Transport and Removal in PEMFC Gas Flow Channel with Various Water Droplet Locations and Channel Surface Wettability

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Yanzhou Qin

2018-04-01

Full Text Available Water transport and removal in the proton exchange membrane fuel cell (PEMFC is critically important to fuel cell performance, stability, and durability. Water emerging locations on the membrane-electrode assembly (MEA surface and the channel surface wettability significantly influence the water transport and removal in PEMFC. In most simulations of water transport and removal in the PEMFC flow channel, liquid water is usually introduced at the center of the MEA surface, which is fortuitous, since water droplet can emerge randomly on the MEA surface in PEMFC. In addition, the commonly used no-slip wall boundary condition greatly confines the water sliding features on hydrophobic MEA/channel surfaces, degrading the simulation accuracy. In this study, water droplet is introduced with various locations along the channel width direction on the MEA surface, and water transport and removal is investigated numerically using an improved model incorporating the sliding flow property by using the shear wall boundary condition. It is found that the water droplet can be driven to the channel sidewall by aerodynamics when the initial water location deviates from the MEA center to a certain amount, forming the water corner flow in the flow channel. The channel surface wettability on the water transport is also studied and is shown to have a significant impact on the water corner flow in the flow channel.

Scattering of thermal neutron by the water molecule

International Nuclear Information System (INIS)

Rosa, L.P.

The calculation of the differenctial cross section for scattering of thermal neutrons by water, taking into account the translational, rotational and vibrational motions of the water molecule, is presented according to Nelkin' model. Some modifications are presented which have been introduced in the original method to improve the results and an application has been made to reactor physics, by calculating the thermal neutron flux in a homogenous medium containing water and absorver. Thirty thermal energy groups have been used to compute the spectra. Within the limits of error, better agreement has been obtained between theory and experiments by using a modified Nelkin kernel consisting of substituting the asymptotic formulae for the rotational and vibrational motions by more exact expressions, similar to the Buttler model for heavy water

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.

Mo and Ni Removal from Drinking Water Using Zeolitic Tuff from Jordan

Directory of Open Access Journals (Sweden)

Khalil M. Ibrahim

2016-11-01

Full Text Available Mo and Ni metals could be hazardous in natural waters. The initial Mo and Ni concentration in the sampled domestic drinking water of north Jordan is 550 and 110 μg/L, respectively. The efficiency of using natural faujasite–phillipsite and phillipsite–chabazite tuffs in removing Mo and Ni from contaminated drinking water was tested. Batch experiments using different weights of the adsorbent were conducted at different contact times to determine the optimum conditions. The maximal uptake capacity of Mo from drinking water was equivalent to 440–420 μg/g adsorbent. The maximum removal efficiency of Mo by faujasite–phillipsite, phillipsite–chabazite, and the modified surfactant phillipsite–chabazite tuffs were 80%, 76%, and 78%, respectively. The proportional relationship between contact time and removal efficiency of Ni from water samples was observed. The maximum removal efficiency of Ni by the zeolitic tuffs is up to 90% compared to the original groundwater sample.

Dispersion of C(60) in natural water and removal by conventional drinking water treatment processes.

Science.gov (United States)

Hyung, Hoon; Kim, Jae-Hong

2009-05-01

The first objective of this study is to examine the fate of C(60) under two disposal scenarios through which pristine C(60) is introduced to water containing natural organic matter (NOM). A method based on liquid-liquid extraction and HPLC to quantify nC(60) in water containing NOM was also developed. When pristine C(60) was added to water either in the form of dry C(60) or in organic solvent, it formed water stable aggregates with characteristics similar to nC(60) prepared by other methods reported in the literature. The second objective of this study is to examine the fate of the nC(60) in water treatment processes, which are the first line of defense against ingestion from potable water -- a potential route for direct human consumption. Results obtained from jar tests suggested that these colloidal aggregates of C(60) were efficiently removed by a series of alum coagulation, flocculation, sedimentation and filtration processes, while the efficiency of removal dependent on various parameters such as pH, alkalinity, NOM contents and coagulant dosage. Colloidal aggregates of functionalized C(60) could be well removed by the conventional water treatment processes but with lesser efficiency compared to those made of pristine C(60).

Nutrient removal from Chinese coastal waters by large-scale seaweed aquaculture

KAUST Repository

Xiao, Xi

2017-04-21

China is facing intense coastal eutrophication. Large-scale seaweed aquaculture in China is popular, now accounting for over 2/3\\'s of global production. Here, we estimate the nutrient removal capability of large-scale Chinese seaweed farms to determine its significance in mitigating eutrophication. We combined estimates of yield and nutrient concentration of Chinese seaweed aquaculture to quantify that one hectare of seaweed aquaculture removes the equivalent nutrient inputs entering 17.8 ha for nitrogen and 126.7 ha for phosphorus of Chinese coastal waters, respectively. Chinese seaweed aquaculture annually removes approximately 75,000 t nitrogen and 9,500 t phosphorus. Whereas removal of the total N inputs to Chinese coastal waters requires a seaweed farming area 17 times larger than the extant area, one and a half times more of the seaweed area would be able to remove close to 100% of the P inputs. With the current growth rate of seaweed aquaculture, we project this industry will remove 100% of the current phosphorus inputs to Chinese coastal waters by 2026. Hence, seaweed aquaculture already plays a hitherto unrealized role in mitigating coastal eutrophication, a role that may be greatly expanded with future growth of seaweed aquaculture.

Nutrient removal from Chinese coastal waters by large-scale seaweed aquaculture

KAUST Repository

Xiao, Xi; Agusti, Susana; Lin, Fang; Li, Ke; Pan, Yaoru; Yu, Yan; Zheng, Yuhan; Wu, Jiaping; Duarte, Carlos M.

2017-01-01

China is facing intense coastal eutrophication. Large-scale seaweed aquaculture in China is popular, now accounting for over 2/3's of global production. Here, we estimate the nutrient removal capability of large-scale Chinese seaweed farms to determine its significance in mitigating eutrophication. We combined estimates of yield and nutrient concentration of Chinese seaweed aquaculture to quantify that one hectare of seaweed aquaculture removes the equivalent nutrient inputs entering 17.8 ha for nitrogen and 126.7 ha for phosphorus of Chinese coastal waters, respectively. Chinese seaweed aquaculture annually removes approximately 75,000 t nitrogen and 9,500 t phosphorus. Whereas removal of the total N inputs to Chinese coastal waters requires a seaweed farming area 17 times larger than the extant area, one and a half times more of the seaweed area would be able to remove close to 100% of the P inputs. With the current growth rate of seaweed aquaculture, we project this industry will remove 100% of the current phosphorus inputs to Chinese coastal waters by 2026. Hence, seaweed aquaculture already plays a hitherto unrealized role in mitigating coastal eutrophication, a role that may be greatly expanded with future growth of seaweed aquaculture.

Experiments on aerosol removal by high-pressure water spray

Energy Technology Data Exchange (ETDEWEB)

Corno, Ada del, E-mail: delcorno@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Morandi, Sonia, E-mail: morandi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Parozzi, Flavio, E-mail: parozzi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Araneo, Lucio, E-mail: lucio.araneo@polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy); CNR-IENI, via Cozzi 53, I-20125 Milano (Italy); Casella, Francesco, E-mail: francesco2.casella@mail.polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy)

2017-01-15

Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m{sup 3}. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m{sup 3}. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was

Experiments on aerosol removal by high-pressure water spray

International Nuclear Information System (INIS)

Corno, Ada del; Morandi, Sonia; Parozzi, Flavio; Araneo, Lucio; Casella, Francesco

2017-01-01

Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO_2 particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m"3. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO_2 particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m"3. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was detected with 1 �

Performance of alum and assorted coagulants in turbidity removal of muddy water

Science.gov (United States)

Malik, Qasim H.

2018-03-01

Coagulation is a primary and cost effective process in water treatment plants. Under optimum conditions, not only it effectively removes turbidity but also results in reduced sludge volume and subsequently minimizes sludge management costs. Highly turbid water from streams, canals, rivers and rain run offs was run through jar test for turbidity removal. The brown water with 250NTU turbidity when coagulated with alum and assorted coagulants proved that maximum turbidity removal was witnessed using alum dose of 0.25 g/l at ph 6 with a sedimentation time of 30 min.

Significantly improving trace thallium removal from surface waters during coagulation enhanced by nanosized manganese dioxide.

Science.gov (United States)

Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Jiang, Jin; Wang, Yaan; Wu, Zhengsong

2017-02-01

Thallium (Tl) is an element of high toxicity and significant accumulation in human body. There is an urgent need for the development of appropriate strategies for trace Tl removal in drinking water treatment plants. In this study, the efficiency and mechanism of trace Tl (0.5 μg/L) removal by conventional coagulation enhanced by nanosized manganese dioxide (nMnO 2 ) were explored in simulated water and two representative surface waters (a river water and a reservoir water obtained from Northeast China). Experimental results showed that nMnO 2 significantly improve Tl(I) removal from selected waters. The removal efficiency was dramatically higher in the simulated water, demonstrating by less than 0.1 μg/L Tl residual. The enhancement of trace Tl removal in the surface waters decreased to a certain extent. Both adjusting water pH to alkaline condition and preoxidation of Tl(I) to Tl(III) benefit trace Tl removal from surface waters. Data also indicated that competitive cation of Ca 2+ decreased the efficiency of trace Tl removal, resulting from the reduction of Tl adsorption on nMnO 2 . Humic acid could largely low Tl removal efficiency during nMnO 2 enhanced coagulation processes. Trace elemental Tl firstly adsorbed on nMnO 2 and then removed accompanying with nMnO 2 settling. The information obtained in the present study may provide a potential strategy for drinking water treatment plants threatened by trace Tl. Copyright © 2016 Elsevier Ltd. All rights reserved.

Filtering Water by Use of Ultrasonically Vibrated Nanotubes

Science.gov (United States)

Gavalas, Lillian Susan

2009-01-01

Devices that could be characterized as acoustically driven molecular sieves have been proposed for filtering water to remove all biological contaminants and all molecules larger than water molecules. Originally intended for purifying wastewater for reuse aboard spacecraft, these devices could also be attractive for use on Earth in numerous settings in which there are requirements to obtain potable, medical-grade, or otherwise pure water from contaminated water supplies. These devices could also serve as efficient means of removing some or all water from chemical products . for example, they might be useful as adjuncts or substitutes for stills in the removal of water from alcohols and alcoholic beverages. These devices may be constructed using various materials, such as ceramics, metallics, or polymers, depending on end-use requirements. A representative device of this type (see figure) would include a polymeric disk, about 1 mm in diameter and between 1 and 40 microns thick, within which would be embedded single-wall carbon nanotubes aligned along the thickness axis. The polymeric disk would be part of a unitary polymeric ring assembly. An acoustic transducer in the form of a piezoelectric-film-and-electrode subassembly - typically 9 microns thick and made of poly(vinylidene fluoride) coated with copper 150 nm thick -. would be affixed to the outside of the outer polymeric ring by means of an electrically nonconductive epoxy. The nanotubes would be chosen to have diameters between about 8 and about 13.5 A because water molecules could fit into the nanotubes, but larger molecules could not. Water to be purified would be placed in contact with one face (typically, the upper face) of the filter disk. The surface tension of water is low enough that water molecules should enter and travel along the nanotubes, and computational simulations of molecular dynamics and experimental measurements have shown that the water molecules inside the nanotubes in this size range can

Factors affecting radon removal from Rn-222 enriched water

International Nuclear Information System (INIS)

Abulfaraj, W.H.; Mamoon, A.

1994-01-01

Continued use of potable well water that has elevated levels of Rn-222 is harmful to human health. activated carbon, aeration and heating can remove radon from treated water. Water artificially enriched with Rn-222 using a pitchblende source was studied in a laboratory scale model under controlled conditions. (author), 3 figs., 3 refs

Materials removal by water jets with high relative velocity

International Nuclear Information System (INIS)

Schikorr, W.

1986-01-01

By way of introduction approaches to the systematic apprehension of the material removal by water jets up to 1000 bar are made. In drilling experiments the effects of jet dynamic are studied, using the controlled disintegration of the jet. Using model-layer-systems the removal of layers by the 'natural' disintegrating fluid-jet is examined. The mechanisms of material removal and the consequences on the praxis of cleaning are discussed. A concept to measure specially the effects of the dynamic jet components is developed. In conclusion aspects of progress in this methods of material removal are discussed. (orig.) [de

Water molecule-enhanced CO2 insertion in lanthanide coordination polymers

International Nuclear Information System (INIS)

Luo Liushan; Huang Xiaoyuan; Wang Ning; Wu Hongyan; Chen Wenbin; Feng Zihao; Zhu Huiping; Peng Xiaoling; Li Yongxian; Huang Ling; Yue Shantang; Liu Yingliang

2009-01-01

Two new lanthanide coordination polymers H 2 N(CH 3 ) 2 .[Eu III 2 (L 1 ) 3 (L 2 )] (1, L 1 =isophthalic acid dianion, L 2 =formic acid anion) and [La III (2,5-PDC)(L 2 )](2, 2,5-PDC=2,5-pyridinedicarboxylate dianion) were synthesized under solvothermal conditions. It is of interest that the formic ligand (L 2 ) is not contained in the stating materials, but arises from the water molecule-enhanced CO 2 insertion during the solvothermal process. Both of the two compounds exhibit complicated three dimensional sandwich-like frameworks. - Graphical abstract: Two new lanthanide coordination polymers involving water molecule-enhanced CO 2 insertion resulting in the formation of formic anion and dimethylammonium cation were synthesized under solvothermal conditions.

Aluminium removal from water after defluoridation with the electrocoagulation process.

Science.gov (United States)

Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

2015-01-01

Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

Ophthalmic ester removal in the agar state giant molecule; Kantenjo kobunshi de futarusan esuteru jokyo

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-10-01

Matsubara professors of Tokyo College of Pharmacy developed the technique which simply removed phthalic ester from the solution. The property in which the giant molecule called the poly N isopropyl acrylamide cohered like the agar, when 32 degrees C is exceeded, was utilized, and the phthalic ester of poor solubility is taken in the flocculation stage. It is expected with that it can be utilized for wastewater treatment and solicitation quantity thing analysis in the environment. (translated by NEDO)

La3+-modified activated alumina for fluoride removal from water

International Nuclear Information System (INIS)

Cheng, Jiemin; Meng, Xiaoguang; Jing, Chuanyong; Hao, Jumin

2014-01-01

Graphical abstract: - Highlights: • A La 3+ -modified activated alumina adsorbent was prepared for effective removal F − . • SEM/EDS and EXAFS analyses determined the formation of La(OH) 3 coating on the AA. • The La-AA had much high adsorption rate and capacity than the AA. • The La-AA was promising adsorbent for effective removal of F − from water. - Abstract: A La 3+ -modified activated alumina (La-AA) adsorbent was prepared for effective removal of fluoride from water. The surface properties of adsorbent were characterized with zeta potential analysis, SEM-EDS and EXAFS. Batch and column experiments were conducted to evaluate improvement of F − removal by the La-AA. SEM/EDS and EXAFS analyses determined the formation of La(OH) 3 coating on the AA and strong bonding interactions between La 3+ and the Al atoms. The points of zero charge (pH PZC ) of AA and La-AA were at pH 8.94 and 9.57, respectively. Batch experimental results indicated that the La-AA had much higher adsorption rate and capacity than the AA. The F − adsorption processes on La-AA and AA followed the pseudo-second-order kinetics and the Langmuir isotherm. Column filtration results shows that the La-AA and AA treated 270 and 170 bed volumes of the F − -spiked tap water, respectively, before F − breakthrough occurred. The results demonstrated that the La-AA was a promising adsorbent for effective removal of F − from water

Novel Photocatalytic Reactor Development for Removal of Hydrocarbons from Water

Directory of Open Access Journals (Sweden)

Morgan Adams

2008-01-01

Full Text Available Hydrocarbons contamination of the marine environment generated by the offshore oil and gas industry is generated from a number of sources including oil contaminated drill cuttings and produced waters. The removal of hydrocarbons from both these sources is one of the most significant challenges facing this sector as it moves towards zero emissions. The application of a number of techniques which have been used to successfully destroy hydrocarbons in produced water and waste water effluents has previously been reported. This paper reports the application of semiconductor photocatalysis as a final polishing step for the removal of hydrocarbons from two waste effluent sources. Two reactor concepts were considered: a simple flat plate immobilised film unit, and a new rotating drum photocatalytic reactor. Both units proved to be effective in removing residual hydrocarbons from the effluent with the drum reactor reducing the hydrocarbon content by 90% under 10 minutes.

Electric dipole moments of nanosolvated acid molecules in water clusters.

Science.gov (United States)

Guggemos, Nicholas; Slavíček, Petr; Kresin, Vitaly V

2015-01-30

The electric dipole moments of (H2O)nDCl (n=3-9) clusters have been measured by the beam-deflection method. Reflecting the (dynamical) charge distribution within the system, the dipole moment contributes information about the microscopic structure of nanoscale solvation. The addition of a DCl molecule to a water cluster results in a strongly enhanced susceptibility. There is evidence for a noticeable rise in the dipole moment occurring at n≈5-6. This size is consistent with predictions for the onset of ionic dissociation. Additionally, a molecular-dynamics model suggests that even with a nominally bound impurity an enhanced dipole moment can arise due to the thermal and zero-point motion of the proton and the water molecules. The experimental measurements and the calculations draw attention to the importance of fluctuations in defining the polarity of water-based nanoclusters and generally to the essential role played by motional effects in determining the response of fluxional nanoscale systems under realistic conditions.

Nuclear reactor with makeup water assist from residual heat removal system

International Nuclear Information System (INIS)

Schulz, T.L.; Corletti, M.M.

1994-01-01

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit by pumping water from an in-containment refueling water storage tank during staged depressurization of the coolant circuit, the final stage including passive emergency cooling by gravity feed from the refueling water storage tank to the coolant circuit and to flood the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and avoids the final stage of depressurization with its flooding of the containment when such action is not necessary, but does not prevent the final stage when it is necessary. A high pressure makeup water storage tank coupled to the reactor coolant circuit holds makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal system can also be coupled in a loop with the refueling water supply tanks for cooling the tank. (Author)

Mercury removal from water streams through the ion exchange membrane bioreactor concept.

Science.gov (United States)

Oehmen, Adrian; Vergel, Dario; Fradinho, Joana; Reis, Maria A M; Crespo, João G; Velizarov, Svetlozar

2014-01-15

Mercury is a highly toxic heavy metal that causes human health problems and environmental contamination. In this study, an ion exchange membrane bioreactor (IEMB) process was developed to achieve Hg(II) removal from drinking water and industrial effluents. Hg(II) transport through a cation exchange membrane was coupled with its bioreduction to Hg(0) in order to achieve Hg removal from concentrated streams, with minimal production of contaminated by-products observed. This study involves (1) membrane selection, (2) demonstration of process effectiveness for removing Hg from drinking water to below the 1ppb recommended limit, and (3) process application for treatment of concentrated water streams, where >98% of the Hg was removed, and the throughput of contaminated water was optimised through membrane pre-treatment. The IEMB process represents a novel mercury treatment technology with minimal generation of contaminated waste, thereby reducing the overall environmental impact of the process. Copyright © 2013 Elsevier B.V. All rights reserved.

Procedure to remove a dirt and/or oil film from water

Energy Technology Data Exchange (ETDEWEB)

Jager, T; Jager, G P.A.; Jager, K L.E.

1970-12-11

A procedure is described to remove dirt and/or oil films from a water surface. A number of rotating wiper scoops moves through the water. The top of the polluted water is brought into motion by the scoops and directed to a gutter system where it is removed. The advantage of the system is that the wiper scoops can be lowered selectively to the depth of the pollutant, thereby avoiding moving large quantities of unnecessary unpolluted liquid which later has to be separated. (12 claims)

Influence of the effective mass of water molecule on thermal neutron scattering

International Nuclear Information System (INIS)

Markovic, M.

1981-01-01

The influence of the effective water molecule mass on the thermal neutron scattering on the nucleus of the hydrogen atom has been investigated. Besides the actual water molecule mass (M = 18) the investigations have been carried out with its two effective values (M1 = 16 and M2 = 20). The differential and total cross sections have been calculated for the incident thermal neutron energy E o = 1 eV. Investigation results show different prominence of the quantum effects and for M2 the appearance of peaks in the quasielastic scattering. (author)

Use of Moringa oleifera seeds for the removal of turbidity of water supply

Directory of Open Access Journals (Sweden)

Gustavo Lopes Muniz

2015-04-01

Full Text Available Water used for human consumption may contain various impurities and solid particles in suspension that increase its turbidity level. Moringa oleifera Lam is a plant that has the potential to be used as coagulating agent in removing turbidity. The objective of this work was to evaluate the efficiency of Moringa oleifera seeds used in shells and without shells in the removal of turbidity from waters with different degrees of turbidity. Waters were used with 70, 250 and 400 initial NTU obtained synthetically. The extract of moringa seeds was prepared using unshelled and shelled seeds, seeking a simplified procedure and practice. The sedimentation times and dose of coagulant solution used were based on existing recommendations in the literature. All treatments were performed with three replicates and the averages depicted in graphs. The results showed that the use of extract of moringa seeds in shells was more efficient than with unshelled seeds in the removal of turbidity of all treatments and that the shelled seeds removed more than 99% of the initial turbidity of the water samples. Furthermore, there was a direct relationship between turbidity removal efficiency and the level of initial turbidity of the samples. The seeds were more efficient in removing turbidity of the water with a higher level of initial turbidity.

Coagulation effectiveness of graphene oxide for the removal of turbidity from raw surface water.

Science.gov (United States)

Aboubaraka, Abdelmeguid E; Aboelfetoh, Eman F; Ebeid, El-Zeiny M

2017-08-01

This study presents the performance of graphene oxide (GO) as a coagulant in turbidity removal from naturally and artificially turbid raw surface water. GO is considered an excellent alternative to alum, the more common coagulant used in water treatment processes, to reduce the environmental release of aluminum. Effects of GO dosage, pH, and temperature on its coagulation ability were studied to determine the ideal turbidity removal conditions. The turbidity removal was ≥95% for all levels of turbid raw surface water (20, 100, and 200 NTU) at optimum conditions. The role of alkalinity in inducing turbidity removal by GO coagulation was much more pronounced upon using raw surface water samples compared with that using artificially turbid deionized water samples. Moreover, GO demonstrated high-performance removal of biological contaminants such as algae, heterotrophic bacteria, and fecal coliform bacteria by 99.0%, 98.8% and 96.0%, respectively, at a dosage of 40 mg/L. Concerning the possible environmental release of GO into the treated water following filtration process, there was no residual GO in a wide range of pH values. The outcomes of the study highlight the excellent coagulation performance of GO for the removal of turbidity and biological contaminants from raw surface water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Turbidity removal from surface water using Tamarindus indica crude ...

African Journals Online (AJOL)

Plant-based coagulants are potential alternatives to chemical coagulants used in drinking water treatment. This paper examined the turbidity removal efficiency of Tamarindus indica fruit crude pulp extract (CPE) towards evaluating a low-cost option for drinking-water treatment. Laboratory analysis was carried out on high ...

Nutrient Removal of Grey Water from Wet Market Using Sequencing Batch Reactor

International Nuclear Information System (INIS)

Omar Danial; Mohd Razman Salim; Salmiati

2016-01-01

Fresh water scarcity has become an important issue in this world today. Water reuse is known as one of the strategies to overcome this problem. Grey water is one of the sources of reused water. Several researches were carried out on water reuse, but limited attention was focused on reusing grey water from wet market, which contains high nutrient and organic matters. This study was carried out on nutrient removal from grey water using sequencing batch reactor (SBR). The grey water sample was taken from a wet market (Pasar Peladang, Skudai). About 1L of grey water was fed into the reactor with a total volume of 4L. Anoxic-aerobic phase were divided with a ratio of 30 % - 70 % of total time respectively. Mixing was maintained at 30 rpm during the start of each cycle until settling phase to achieve uniform condition. Influent and effluent were set for 30 minutes. The SBR was operated with 3 cycles/ day, temperature 30 degree Celsius, cycle time 8 hours and hydraulic retention time (HRT) 1.2 days. Aeration at 35 L/ min was induced for ammonia conversion and assisting nitrification.. The results show that the bacteria growing in alternating anoxic/ aerobic systems could remove organic substrates and nutrient. The COD, Total Nitrogen and Total Phosphorus removal efficiencies were maximum at the levels of 94 %, 88 % and 70 % respectively. Anaerobic-Aerobic-Anoxic phase was proposed to increase the removal percentage. (author)

Solvated protein-protein docking using Kyte-Doolittle-based water preferences

NARCIS (Netherlands)

Kastritis, P.; Visscher, K.M.; van Dijk, A.D.J.; Bonvin, A.M.J.J.

2013-01-01

HADDOCK is one of the few docking programs that can explicitly account for water molecules in the docking process. Its solvated docking protocol starts from hydrated molecules and a fraction of the resulting interfacial waters is subsequently removed in a biased Monte Carlo procedure based on

Solvated protein-protein docking using Kyte-Doolittle-based water preferences

NARCIS (Netherlands)

Kastritis, Panagiotis L.; Visscher, Koen M.; van Dijk, Aalt D.J.; Bonvin, Alexandre M.J.J.

HADDOCK is one of the few docking programs that can explicitly account for water molecules in the docking process. Its solvated docking protocol starts from hydrated molecules and a fraction of the resulting interfacial waters is subsequently removed in a biased Monte Carlo procedure based on

Removal of Arsenic from Drinking Water by Adsorption and Coagulation

Science.gov (United States)

Zhang, M.; Sugita, H.; Hara, J.; Takahashi, S.

2013-12-01

Removal of arsenic from drinking water has been an important issue worldwide, which has attracted greater attentions in recent years especially for supplying safe drinking water in developing countries. Although many kinds of treatment approaches that are available or applicable both in principle and practice, such as adsorption, coagulation, membrane filtration, ion exchange, biological process, electrocoagulation and so on, the first 2 approaches (i.e., adsorption and coagulation) are most promising due to the low-cost, high-efficiency, simplicity of treating systems, and thus can be practically used in developing countries. In this study, a literature survey on water quality in Bangladesh was performed to understand the ranges of arsenic concentration and pH of groundwater in Bangladesh. A series of tests were then organized and performed to investigate the effects of arsenic concentration, arsenic forms, pH, chemical compositions of the materials used for adsorption and coagulation, particle size distribution and treatment time on quality of treated water. The experimental results obtained in the study illustrated that both adsorption and coagulation can be used to effectively reduce the concentrations of either arsenic (V) or arsenic (III) from the contaminated water. Coagulation of arsenic with a magnesium-based material developed in this study can be very effective to remove arsenic, especially arsenic (V), from contaminated water with a concentration of 10 ppm to an undetectable level of 0.002 ppm by ICP analyses. Compared to arsenic (III), arsenic (V) is easier to be removed. The materials used for adsorption and coagulation in this study can remove arsenic (V) up to 9 mg/g and 6 mg/g, and arsenic (III) up to 4 mg/g and 3 mg/g, respectively, depending on test conditions and compositions of the materials being used. The control of pH during treatment can be a challenging technical issue for developing both adsorbent and coagulant. Keywords: Water Treatment

A Raman spectroscopy study on the effects of intermolecular hydrogen bonding on water molecules absorbed by borosilicate glass surface

Science.gov (United States)

Li, Fabing; Li, Zhanlong; Wang, Ying; Wang, Shenghan; Wang, Xiaojun; Sun, Chenglin; Men, Zhiwei

2018-05-01

The structural forms of water/deuterated water molecules located on the surface of borosilicate capillaries have been first investigated in this study on the basis of the Raman spectral data obtained at different temperatures and under atmospheric pressure for molecules in bulk and also for molecules absorbed by borosilicate glass surface. The strongest two fundamental bands locating at 3063 cm-1 (2438 cm-1) in the recorded Raman spectra are assigned here to the Osbnd H (Osbnd D) bond stretching vibrations and they are compared with the corresponding bands observed at 3124 cm-1 (2325 cm-1) in the Raman spectrum of ice Ih. Our spectroscopic observations have indicated that the structure of water and deuterated water molecules on borosilicate surface is similar to that of ice Ih (hexagonal phase of ice). These observations have also indicated that water molecules locate on the borosilicate surface so as to construct a bilayer structure and that strong and weak intermolecular hydrogen bonds are formed between water/deuterated molecules and silanol groups on borosilicate surface. In accordance with these findings, water and deuterated water molecules at the interface of capillary have a higher melting temperature.

Transport behavior of water molecules through two-dimensional nanopores

International Nuclear Information System (INIS)

Zhu, Chongqin; Li, Hui; Meng, Sheng

2014-01-01

Water transport through a two-dimensional nanoporous membrane has attracted increasing attention in recent years thanks to great demands in water purification and desalination applications. However, few studies have been reported on the microscopic mechanisms of water transport through structured nanopores, especially at the atomistic scale. Here we investigate the microstructure of water flow through two-dimensional model graphene membrane containing a variety of nanopores of different size by using molecular dynamics simulations. Our results clearly indicate that the continuum flow transits to discrete molecular flow patterns with decreasing pore sizes. While for pores with a diameter ≥15 Å water flux exhibits a linear dependence on the pore area, a nonlinear relationship between water flux and pore area has been identified for smaller pores. We attribute this deviation from linear behavior to the presence of discrete water flow, which is strongly influenced by the water-membrane interaction and hydrogen bonding between water molecules

Chemical reactions of water molecules on Ru(0001) induced by selective excitation of vibrational modes

Energy Technology Data Exchange (ETDEWEB)

Mugarza, Aitor; Shimizu, Tomoko K.; Ogletree, D. Frank; Salmeron, Miquel

2009-05-07

Tunneling electrons in a scanning tunneling microscope were used to excite specific vibrational quantum states of adsorbed water and hydroxyl molecules on a Ru(0 0 0 1) surface. The excited molecules relaxed by transfer of energy to lower energy modes, resulting in diffusion, dissociation, desorption, and surface-tip transfer processes. Diffusion of H{sub 2}O molecules could be induced by excitation of the O-H stretch vibration mode at 445 meV. Isolated molecules required excitation of one single quantum while molecules bonded to a C atom required at least two quanta. Dissociation of single H{sub 2}O molecules into H and OH required electron energies of 1 eV or higher while dissociation of OH required at least 2 eV electrons. In contrast, water molecules forming part of a cluster could be dissociated with electron energies of 0.5 eV.

Removal of virus to protozoan sized particles in point-of-use ceramic water filters.

Science.gov (United States)

Bielefeldt, Angela R; Kowalski, Kate; Schilling, Cherylynn; Schreier, Simon; Kohler, Amanda; Scott Summers, R

2010-03-01

The particle removal performance of point-of-use ceramic water filters (CWFs) was characterized in the size range of 0.02-100 microm using carboxylate-coated polystyrene fluorescent microspheres, natural particles and clay. Particles were spiked into dechlorinated tap water, and three successive water batches treated in each of six different CWFs. Particle removal generally increased with increasing size. The removal of virus-sized 0.02 and 0.1 microm spheres were highly variable between the six filters, ranging from 63 to 99.6%. For the 0.5 microm spheres removal was less variable and in the range of 95.1-99.6%, while for the 1, 2, 4.5, and 10 microm spheres removal was >99.6%. Recoating four of the CWFs with colloidal silver solution improved removal of the 0.02 microm spheres, but had no significant effects on the other particle sizes. Log removals of 1.8-3.2 were found for natural turbidity and spiked kaolin clay particles; however, particles as large as 95 microm were detected in filtered water. Copyright 2009 Elsevier Ltd. All rights reserved.

Improvement of NOM Removal from Water Resources by Modifying the Coagulation Process

Directory of Open Access Journals (Sweden)

F Vaezi, A Mohagheghian, J Nouri, MR Eshraghian, A Ghasri

2005-01-01

Full Text Available As a result of the regulations on DBPs, interest in NOM removal is increasing and many water treatment plants in developed countries have started to measure the concentration of TOC in their finished waters. Promulgation of the rules will substantially increase these efforts in other countries too. Since the cost of TOC (and DBPs determination was high, it was decided to study the traditional analysis of COD as a surrogate measure to detect the organic constituents in raw water and the extent to which optimized coagulation with ferric chloride can increase COD removal. The two water samples studied belonged to Karaj and Jajrood Rivers. For both samples the observed values of COD removal by coagulation at lower pH (about 1-1.5 pH values less than the regular pH were about 85-95 percent without making water turbidity unacceptable. In order to determine the effects of organic content on coagulation, synthetic samples were also prepared with much higher COD values. Again, considerable increases in COD removal have been observed for most of these samples only by decreasing 0.5-2 pH value. The results indicated that a modified coagulation process without need to much increasing the amount of coagulant can be developed for these water samples.

The removal of uranium from mining waste water using algal/microbial biomass

International Nuclear Information System (INIS)

Kalin, Margarete; Wheeler, W.N.; Meinrath, G.

2004-01-01

We describe a three step process for the removal of uranium (U) from dilute waste waters. Step one involves the sequestration of U on, in, and around aquatic plants such as algae. Cell wall ligands efficiently remove U(VI) from waste water. Growing algae continuously renew the cellular surface area. Step 2 is the removal of U-algal particulates from the water column to the sediments. Step 3 involves reducing U(VI) to U(IV) and transforming the ions into stable precipitates in the sediments. The algal cells provide organic carbon and other nutrients to heterotrophic microbial consortia to maintain the low E H , within which the U is transformed. Among the microorganisms, algae are of predominant interest for the ecological engineer because of their ability to sequester U and because some algae can live under many extreme environments, often in abundance. Algae grow in a wide spectrum of water qualities, from alkaline environments (Chara, Nitella) to acidic mine drainage waste waters (Mougeotia, Ulothrix). If they could be induced to grow in waste waters, they would provide a simple, long-term means to remove U and other radionuclides from U mining effluents. This paper reviews the literature on algal and microbial adsorption, reduction, and transformation of U in waste streams, wetlands, lakes and oceans

Phytoremediation to remove nutrients and improve eutrophic stormwaters using water lettuce (Pistia stratiotes L.).

Science.gov (United States)

Lu, Qin; He, Zhenli L; Graetz, Donald A; Stoffella, Peter J; Yang, Xiaoe

2010-01-01

Water quality impairment by nutrient enrichment from agricultural activities has been a concern worldwide. Phytoremediation technology using aquatic plants in constructed wetlands and stormwater detention ponds is increasingly applied to remediate eutrophic waters. The objectives of this study were to evaluate the effectiveness and potential of water lettuce (Pistia stratiotes L.) in removing nutrients including nitrogen (N) and phosphorus (P) from stormwater in the constructed water detention systems before it is discharged into the St. Lucie Estuary, an important surface water system in Florida, using phytoremediation technologies. In this study, water lettuce (P. stratiotes) was planted in the treatment plots of two stormwater detention ponds (East and West Ponds) in 2005-2007 and water samples from both treatment and control plots were weekly collected and analyzed for water quality properties including pH, electrical conductivity, turbidity, suspended solids, and nutrients (N and P). Optimum plant density was maintained and plant samples were collected monthly and analyzed for nutrient contents. Water quality in both ponds was improved, as evidenced by decreases in water turbidity, suspended solids, and nutrient concentrations. Water turbidity was decreased by more than 60%. Inorganic N (NH(4) (+) and NO(3) (-)) concentrations in treatment plots were more than 50% lower than those in control plots (without plant). Reductions in both PO(4) (3-) and total P were approximately 14-31%, as compared to the control plots. Water lettuce contained average N and P concentrations of 17 and 3.0 g kg(-1), respectively, and removed 190-329 kg N ha(-1) and 25-34 kg P ha(-1) annually. Many aquatic plants have been used to remove nutrients from eutrophic waters but water lettuce proved superior to most other plants in nutrient removal efficiency, owing to its rapid growth and high biomass yield potential. However, the growth and nutrient removal potential are affected by many

Removal of Perfluorinated Compounds From Water using Nanoscale Zero-Valent Iron

OpenAIRE

Arvaniti, Olga S.; Hwang, Yuhoon; Andersen, Henrik Rasmus; Nikolaos, Thomaidis S.; Athanasios, Stasinakis S.

2014-01-01

Perfluorinated Compounds (PFCs) are persistent micropollutants that have been detected in various environmental and biological matrices, worldwide. During the last decade, these compounds have also been detected in municipal wastewater and tap water. Due to the stability of C-F bond, the application of biological and conventional physicochemical treatment methods does not seem to remove sufficient these compounds from water and wastewater. In the current study, the removal efficiency of four ...

ETV REPORT: REMOVAL OF ARSENIC IN DRINKING WATER ORCA WATER TECHNOLOGIES KEMLOOP 1000 COAGULATION AND FILTRATION WATER TREATMENT SYSTEM

Science.gov (United States)

Verification testing of the ORCA Water Technologies KemLoop 1000 Coagulation and Filtration Water Treatment System for arsenic removal was conducted at the St. Louis Center located in Washtenaw County, Michigan, from March 23 through April 6, 2005. The source water was groundwate...

Permeability of uncharged organic molecules in reverse osmosis desalination membranes.

Science.gov (United States)

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

2017-06-01

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

Hydrogen bonding characterization in water and small molecules

Science.gov (United States)

Silvestrelli, Pier Luigi

2017-06-01

The prototypical hydrogen bond in water dimer and hydrogen bonds in the protonated water dimer, in other small molecules, in water cyclic clusters, and in ice, covering a wide range of bond strengths, are theoretically investigated by first-principles calculations based on density functional theory, considering not only a standard generalized gradient approximation functional but also, for the water dimer, hybrid and van der Waals corrected functionals. We compute structural, energetic, and electrostatic (induced molecular dipole moments) properties. In particular, hydrogen bonds are characterized in terms of differential electron density distributions and profiles, and of the shifts of the centres of maximally localized Wannier functions. The information from the latter quantities can be conveyed to a single geometric bonding parameter that appears to be correlated with the Mayer bond order parameter and can be taken as an estimate of the covalent contribution to the hydrogen bond. By considering the water trimer, the cyclic water hexamer, and the hexagonal phase of ice, we also elucidate the importance of cooperative/anticooperative effects in hydrogen-bonding formation.

Combining Ferric Salt and Cactus Mucilage for Arsenic Removal from Water.

Science.gov (United States)

Fox, Dawn I; Stebbins, Daniela M; Alcantar, Norma A

2016-03-01

New methods to remediate arsenic-contaminated water continue to be studied, particularly to fill the need for accessible methods that can significantly impact developing communities. A combination of cactus mucilage and ferric (Fe(III)) salt was investigated as a flocculation-coagulation system to remove arsenic (As) from water. As(V) solutions, ferric nitrate, and mucilage suspensions were mixed and left to stand for various periods of time. Visual and SEM observations confirmed the flocculation action of the mucilage as visible flocs formed and settled to the bottom of the tubes within 3 min. The colloidal suspensions without mucilage were stable for up to 1 week. Sample aliquots were tested for dissolved and total arsenic by ICP-MS and HGAFS. Mucilage treatment improved As removal (over Fe(III)-only treatment); the system removed 75-96% As in 30 min. At neutral pH, removal was dependent on Fe(III) and mucilage concentration and the age of the Fe(III) solution. The process is fast, achieving maximum removal in 30 min, with the majority of As removed in 10-15 min. Standard jar tests with 1000 μg/L As(III) showed that arsenic removal and settling rates were pH-dependent; As removal was between 52% (high pH) and 66% (low pH).

A review of cyanobacteria and cyanotoxins removal/inactivation in drinking water treatment.

Science.gov (United States)

Westrick, Judy A; Szlag, David C; Southwell, Benjamin J; Sinclair, James

2010-07-01

This review focuses on the efficiency of different water treatment processes for the removal of cyanotoxins from potable water. Although several investigators have studied full-scale drinking water processes to determine the efficiency of cyanotoxin inactivation, many of the studies were based on ancillary practice. In this context, "ancillary practice" refers to the removal or inactivation of cyanotoxins by standard daily operational procedures and without a contingency operational plan utilizing specific treatment barriers. In this review, "auxiliary practice" refers to the implementation of inactivation/removal treatment barriers or operational changes explicitly designed to minimize risk from toxin-forming algae and their toxins to make potable water. Furthermore, the best drinking water treatment practices are based on extension of the multibarrier approach to remove cyanotoxins from water. Cyanotoxins are considered natural contaminants that occur worldwide and specific classes of cyanotoxins have shown regional prevalence. For example, freshwaters in the Americas often show high concentrations of microcystin, anatoxin-a, and cylindrospermopsin, whereas Australian water sources often show high concentrations of microcystin, cylindrospermopsin, and saxitoxins. Other less frequently reported cyanotoxins include lyngbyatoxin A, debromoaplysiatoxin, and beta-N-methylamino-L-alanine. This review focuses on the commonly used unit processes and treatment trains to reduce the toxicity of four classes of cyanotoxins: the microcystins, cylindrospermopsin, anatoxin-a, and saxitoxins. The goal of this review is to inform the reader of how each unit process participates in a treatment train and how an auxiliary multibarrier approach to water treatment can provide safer water for the consumer.

Removal of chromium (VI) from water by micro-alloyed aluminium ...

African Journals Online (AJOL)

This paper deals with Cr(VI) ion removal from water, by micro-alloyed aluminium composite (MAlC), under flow conditions. In a water environment the MAlC acts as a strong reducing agent. Dissolving it in water is accompanied by the generation of Al(III) ions and reduction of water to H2, with OH- ions. The final product is ...

Clinoptilolite in Drinking Water Treatment for Ammonia Removal

Directory of Open Access Journals (Sweden)

H. M. Abd El-Hady

2001-01-01

Full Text Available In most countries today the removal of ammonium ions from drinking water has become almost a necessity. The natural zeolite clinoptiloliteis mined commercially in many parts of the world. It is a selective exchanger for the ammonium cation, and this has prompted its use in water treatment, wastewater treatment, swimming pools and fish farming. The work described in this paper provides dynamic data on cation exchange processes in clinoptilolite involving the NH4 +, Ca+2 and Mg+2 cations. We used material of natural origin – clinoptilolite from Nižný Hrabovec in Slovakia (particle-size 3–5 mm. The breakthrough capacity was determined by dynamic laboratory investigations, and we investigated the influence of thermal pretreatment of clinoptilolite and the concentration of regenerant solution (2, 5, and 10% NaCl. The concentrations of ammonium ion inputs in the tap water that we used were 10, 5, and 2 mg NH4 + l_1 and down to levels below 0.5 mg NH4 + l_1. The experimental results show that repeated pretreatment sufficiently improves the zeolite’s properties, and the structure of clinoptilolite remains unchanged during the loading and regeneration cycles. Ammonium removal capacities were increased by approximately 40 % and 20 % for heat-treated zeolite samples. There was no difference between the regenerates for 10% and 5% NaCl. We conclude that the use of zeolite is an attractive and promising method for ammonium removal.

Water-mediated influence of a crowded environment on internal vibrations of a protein molecule.

Science.gov (United States)

Kuffel, Anna; Zielkiewicz, Jan

2016-02-14

The influence of crowding on the protein inner dynamics is examined by putting a single protein molecule close to one or two neighboring protein molecules. The presence of additional molecules influences the amplitudes of protein fluctuations. Also, a weak dynamical coupling of collective velocities of surface atoms of proteins separated by a layer of water is detected. The possible mechanisms of these phenomena are described. The cross-correlation function of the collective velocities of surface atoms of two proteins was decomposed into the Fourier series. The amplitude spectrum displays a peak at low frequencies. Also, the results of principal component analysis suggest that the close presence of an additional protein molecule influences the high-amplitude, low-frequency modes in the most prominent way. This part of the spectrum covers biologically important protein motions. The neighbor-induced changes in the inner dynamics of the protein may be connected with the changes in the velocity power spectrum of interfacial water. The additional protein molecule changes the properties of solvation water and in this way it can influence the dynamics of the second protein. It is suggested that this phenomenon may be described, at first approximation, by a damped oscillator driven by an external random force. This model was successfully applied to conformationally rigid Choristoneura fumiferana antifreeze protein molecules.

Removing uranium from drinking water by metal hydroxides and anion-exchange resin

International Nuclear Information System (INIS)

Lee, S.Y.; Bondietti, E.A.

1983-01-01

Results of bench-scale testing on uranium removal from a natural water that was chosen as a good representative of uranium-bearing waters indicated that conventional coagulant and lime softening treatment removes more than 85 percent of dissolved uranium (83 μg U/L) when an optimum pH and dosage were provided. A strong base anion-exchange column is a recommended option for the treatment of private well waters containing uranium at higher than desirable levels

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

Directory of Open Access Journals (Sweden)

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

2009-10-01

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

Use of polymeric resins for removing contaminants from oily waters

Energy Technology Data Exchange (ETDEWEB)

Clarisse, M.D.; Queiros, Y.G.C.; Mauro, A.C.; Lucas, E.F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas; Barbosa, C.C.R. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Barbosa, L.C.F.; Louvisse, A.M.T. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2004-07-01

Polymeric resins are being tried as an alternative material for treating oily waters from the petroleum industry, which have already been treated by conventional methods. The objective of this work has been to evaluate the purification degree of synthetic oily waters when treated in fixed bed columns packed with polymeric resins made up of hydrophilic and lipophilic moieties. The analysis used for characterizing the total grease and oil content (TOG) was fluorimetry. Starting oily waters of average TOG 40 ppm were prepared. Data obtained from eluted waters did not outweigh 1% of the TOG values of starting solutions. The kinetic study showed that the contaminant removal efficiency depends on the system elution flow rate; optimum removal values were reached at a 7.0 mL/min flow rate. High efficiency and speed in the purification process were obtained at this optimum flow rate. The passage of a water volume 1,000 times the volume of the column bed was not sufficient to observe its saturation level. (author)

Technologies for Arsenic Removal from Water: Current Status and Future Perspectives.

Science.gov (United States)

Nicomel, Nina Ricci; Leus, Karen; Folens, Karel; Van Der Voort, Pascal; Du Laing, Gijs

2015-12-22

This review paper presents an overview of the available technologies used nowadays for the removal of arsenic species from water. Conventionally applied techniques to remove arsenic species include oxidation, coagulation-flocculation, and membrane techniques. Besides, progress has recently been made on the utility of various nanoparticles for the remediation of contaminated water. A critical analysis of the most widely investigated nanoparticles is presented and promising future research on novel porous materials, such as metal organic frameworks, is suggested.

Removal of arsenic from contaminated water using coagulation enhanced microfiltration

International Nuclear Information System (INIS)

Volchek, K.; Velicogna, D.; Dumouchel, A.; Wong, W.P.; Brown, C.E.

2002-01-01

Results of an innovative arsenic removal process were presented. The process is based on a combination of coagulation and microfiltration processes. Coagulation-Enhanced Microfiltration (CEMF) may eventually become a full-scale commercial technology. This study focused on the process with respect to groundwater treatment because of the importance of arsenic contamination in drinking water. Most experiments were bench-scale using tap water spiked with arsenic. Ferric chloride, which is commonly used in arsenic removal processes was also added. In addition, some tests were conducted on actual arsenic-contaminated water from the effluent treatment plant of a former mining site in Ontario. Results indicate a high arsenic removal efficiency in both spiked and actual water solutions. The microfiltration significantly reduced the level of arsenic in the treatment. This paper described the characteristics of membrane separation. It also presented information regarding chemically enhanced membrane filtration and coagulation-enhanced microfiltration. Bench-scale tests were conducted with both tubular membranes and with immersed capillary membranes. The effect of iron to arsenic ratios on the effectiveness of the system was also tested. It was recommended that future research should include a field study of the process on a pilot-scale to optimize process parameters and to accurately determine the cost of the process. 16 refs., 8 tabs., 9 figs

Nitrate removal from drinking water with a focus on biological methods: a review.

Science.gov (United States)

Rezvani, Fariba; Sarrafzadeh, Mohammad-Hossein; Ebrahimi, Sirous; Oh, Hee-Mock

2017-05-31

This article summarizes several developed and industrial technologies for nitrate removal from drinking water, including physicochemical and biological techniques, with a focus on autotrophic nitrate removal. Approaches are primarily classified into separation-based and elimination-based methods according to the fate of the nitrate in water treatment. Biological denitrification as a cost-effective and promising method of biological nitrate elimination is reviewed in terms of its removal process, applicability, efficiency, and associated disadvantages. The various pathways during biological nitrate removal, including assimilatory and dissimilatory nitrate reduction, are also explained. A comparative study was carried out to provide a better understanding of the advantages and disadvantages of autotrophic and heterotrophic denitrification. Sulfur-based and hydrogen-based denitrifications, which are the most common autotrophic processes of nitrate removal, are reviewed with the aim of presenting the salient features of hydrogenotrophic denitrification along with some drawbacks of the technology and research areas in which it could be used but currently is not. The application of algae-based water treatment is also introduced as a nature-inspired approach that may broaden future horizons of nitrate removal technology.

Phosphonate removal from discharged circulating cooling water using iron-carbon micro-electrolysis.

Science.gov (United States)

Zhou, Zhen; Qiao, Weimin; Lin, Yangbo; Shen, Xuelian; Hu, Dalong; Zhang, Jianqiao; Jiang, Lu-Man; Wang, Luochun

2014-01-01

Phosphonate is a commonly used corrosion and scale inhibitor for a circulating cooling water (CCW) system. Its discharge could cause eutrophication of receiving waters. The iron-carbon (Fe/C) micro-electrolysis technology was used to degrade and remove phosphonate from discharged CCW. The influences of initial pH, Fe/C ratio (FCR) and temperature on phosphonate removal were investigated in a series of batch tests and optimized by response surface methodology. The quadratic model of phosphonate removal was obtained with satisfactory degrees of fitness. The optimum conditions with total phosphorus removal efficiency of 95% were obtained at pH 7.0, FCR of 1.25, and temperature of 45 °C. The phosphonate removal mechanisms were also studied. Phosphonate removal occurred predominantly via two consecutive reactive phases: the degradation of phosphonate complexes (Ca-phosphonate) and the precipitation of Fe/C micro-electrolysis products (PO₄(3-), Ca²⁺ and Fe³⁺).

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

International Nuclear Information System (INIS)

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

2009-01-01

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.

Manganese removal from mine waters - investigating the occurrence and importance of manganese carbonates

International Nuclear Information System (INIS)

Bamforth, Selina M.; Manning, David A.C.; Singleton, Ian; Younger, Paul L.; Johnson, Karen L.

2006-01-01

Manganese is a common contaminant of mine water and other waste waters. Due to its high solubility over a wide pH range, it is notoriously difficult to remove from contaminated waters. Previous systems that effectively remove Mn from mine waters have involved oxidising the soluble Mn(II) species at an elevated pH using substrates such as limestone and dolomites. However it is currently unclear what effect the substrate type has upon abiotic Mn removal compared to biotic removal by in situ micro-organisms (biofilms). In order to investigate the relationship between substrate type, Mn precipitation and the biofilm community, net-alkaline Mn-contaminated mine water was treated in reactors containing one of the pure materials: dolomite, limestone, magnesite and quartzite. Mine water chemistry and Mn removal rates were monitored over a 3-month period in continuous-flow reactors. For all substrates except quartzite, Mn was removed from the mine water during this period, and Mn minerals precipitated in all cases. In addition, the plastic from which the reactor was made played a role in Mn removal. Manganese oxyhydroxides were formed in all the reactors; however, Mn carbonates (specifically kutnahorite) were only identified in the reactors containing quartzite and on the reactor plastic. Magnesium-rich calcites were identified in the dolomite and magnesite reactors, suggesting that the Mg from the substrate minerals may have inhibited Mn carbonate formation. Biofilm community development and composition on all the substrates was also monitored over the 3-month period using denaturing gradient gel electrophoresis (DGGE). The DGGE profiles in all reactors showed no change with time and no difference between substrate types, suggesting that any microbiological effects are independent of mineral substrate. The identification of Mn carbonates in these systems has important implications for the design of Mn treatment systems in that the provision of a carbonate-rich substrate

The Use of Activated Alumina and Magnetic Field for the Removal Heavy Metals from Water

Directory of Open Access Journals (Sweden)

Ewa Szatyłowicz

2018-05-01

Full Text Available The objective of this work was to verify the granular activated alumina (AA sorption properties, during the process of removing copper, lead and cadmium from water, and to monitor the impact of magnetic field (MF on the effectiveness of removing copper, lead and cadmium from water. Activated alumina adsorption is known to be an effective and inexpensive technology for the removal of selenium and arsenic from water and was suggested by EPA as a BAT for point-of-use applications. The removal of copper, lead and cadmium from water using AA and impact of magnetic field was less reported. Pilot tests showed that the use of AA sorption materials with MF impact could possibly decrease the copper, lead and cadmium content in the model water. The MF had also a positive effect on the efficiency of removal copper, lead and cadmium on AA. Increasing the efficiency of heavy metals removal in the samples had been exposed magnetic field varied from 1.9% to 8.2% compared to the control samples.

Organically modified clay removes oil from water

International Nuclear Information System (INIS)

Alther, G.R.

1995-01-01

When bentonite or other clays and zeolites are modified with quaternary amines, they become organophilic. Such modified bentonites are used to remove mechanically emulsified oil and grease, and other sparingly soluble organics. If the organoclay is granulated, it is placed into a liquid phase carbon filter vessel to remove FOG's and chlorinated hydrocarbons. In this application the clay is mixed with anthrazite to prevent early plugging of the filter by oil or grease droplets. In batch systems a powered organoclay is employed. Types of oil found in water can include fats, lubricants, cutting fluids, heavy hydrocarbons such as tars, grease, crude oil, diesel oils; and light hydrocarbons such as kerosene, jet fuel, and gasoline

Perchlorate: Health Effects and Technologies for Its Removal from Water Resources

Directory of Open Access Journals (Sweden)

Thiruvenkatachari Viraraghavan

2009-04-01

Full Text Available Perchlorate has been found in drinking water and surface waters in the United States and Canada. It is primarily associated with release from defense and military operations. Natural sources include certain fertilizers and potash ores. Although it is a strong oxidant, perchlorate is very persistent in the environment. At high concentrations perchlorate can affect the thyroid gland by inhibiting the uptake of iodine. A maximum contaminant level has not been set, while a guidance value of 6 ppb has been suggested by Health Canada. Perchlorate is measured in environmental samples primarily by ion chromatography. It can be removed from water by anion exchange or membrane filtration. Biological and chemical processes are also effective in removing this species from water.

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

KAUST Repository

Dehwah, Abdullah

2016-10-18

An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed. Between 44 and over 90% of the transparent exopolymer particles (TEP) are removed with a corresponding significant reduction in concentration of the colloidal fraction of TEP. The removal rate for TEP appears to be greater in carbonate aquifers compared to siliciclastic systems. Although the production wells range in age from 4 months to 14 years, no significant difference in the degree of water treatment provided by the aquifer was found.

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

KAUST Repository

Dehwah, Abdullah; Almashharawi, Samir; Ng, Kim Choon; Missimer, Thomas M.

2016-01-01

An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed. Between 44 and over 90% of the transparent exopolymer particles (TEP) are removed with a corresponding significant reduction in concentration of the colloidal fraction of TEP. The removal rate for TEP appears to be greater in carbonate aquifers compared to siliciclastic systems. Although the production wells range in age from 4 months to 14 years, no significant difference in the degree of water treatment provided by the aquifer was found.

Removal of micropollutants from aerobically treated grey water via ozone and activated carbon

NARCIS (Netherlands)

Hernandez Leal, L.; Temmink, B.G.; Zeeman, G.; Buisman, C.J.N.

2011-01-01

Ozonation and adsorption onto activated carbon were tested for the removal micropollutants of personal care products from aerobically treated grey water. MilliQ water spiked with micropollutants (100–1600 µgL-1) was ozonated at a dosing rate of 1.22. In 45 min, this effectively removed (>99%):

Efficiency of water removal from water/ethanol mixtures using supercritical carbon dioxide

Directory of Open Access Journals (Sweden)

M. A. Rodrigues

2006-06-01

Full Text Available Techniques involving supercritical carbon dioxide have been successfully used for the formation of drug particles with controlled size distributions. However, these processes show some limitations, particularly in processing aqueous solutions. A diagram walking algorithm based on available experimental data was developed to evaluate the effect of ethanol on the efficiency of water removal processes under different process conditions. Ethanol feeding was the key parameter resulting in a tenfold increase in the efficiency of water extraction.

Heavy metal removal from waste waters by ion flotation

OpenAIRE

Polat, Hürriyet; Erdoğan, D.

2007-01-01

Flotation studies were carried out to investigate the removal of heavy metals such as copper (II), zinc (II), chromium (III) and silver (I) from waste waters. Various parameters such as pH, collector and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol and methyl isobutyl carbinol (MIBC) were used as frothers. Metal removal reached about 74% under o...

Radon-removal techniques for small community public water supplies

International Nuclear Information System (INIS)

Kinner, N.E.; Malley, J.P.; Clement, J.A.; Quern, P.A.; Schell, G.S.

1990-08-01

The report presents the results of an evaluation, performed by the University of New Hampshire--Environmental Research Group (ERG), of radon removal in small community water supplies using full-scale granular activated carbon adsorption, diffused bubble aeration and packed tower aeration. Various low technology alternatives, such as loss in a distribution system and addition of coarse bubble aeration to a pilot-scale atmospheric storage tank were also evaluated. The report discusses each of the treatment alternatives with respect to their radon removal efficiency, potential problems (i.e., waste disposal, radiation exposure and intermedia pollution), and economics in small community applications. In addition, several sampling methods, storage times, scintillation cocktails and extraction procedures currently used in the liquid scintillation technique for analysis of radon in water were compared

Technologies for Arsenic Removal from Water: Current Status and Future Perspectives

Directory of Open Access Journals (Sweden)

Nina Ricci Nicomel

2015-12-01

Full Text Available This review paper presents an overview of the available technologies used nowadays for the removal of arsenic species from water. Conventionally applied techniques to remove arsenic species include oxidation, coagulation-flocculation, and membrane techniques. Besides, progress has recently been made on the utility of various nanoparticles for the remediation of contaminated water. A critical analysis of the most widely investigated nanoparticles is presented and promising future research on novel porous materials, such as metal organic frameworks, is suggested.

Removal of oil products from fitters in water treatment plants

International Nuclear Information System (INIS)

Carlson, B.B.; Olander, M.A.; Arvin, E.

1996-01-01

Gasoline and oil spills cause aromatic hydrocarbon pollution of ground water. Benzene, toluene and naphtalene can be found in water wells. The purpose of the experiment was to investigate the filtering of water and biological degradation of aromatics on water treatment filters. These filters were proved to reduce benzene, toluene and naphtalene concentration from 5-12 μg/l to 0,3-0,6 μg/l (86-98 % removal). (EG)

Endotoxin Removal from Water Using Heterogenus Catalytic Ozonation by Bone Char

Directory of Open Access Journals (Sweden)

Abas Rezaee

2011-10-01

Full Text Available The endotoxin is one of pollutants with lipopolysaccharide structure which release from gram negative bacteria and cyanobacters. The aim of this study was removal of endotoxin from water using catalytic ozonation by bone char. The endotoxin for experiments have extracted from Escherichia coli bacterium cell wall by Stefan and Jan method. Chromogenic limulus ambusite lysate method in 405-410 nm wave length was used for analysing of endotoxin. The ozone have analysed by potassium iodine method. Results: Results of the research shown endotoxin removal rates using heterogenous catalytic ozonation were 6.0 Eu/ml.min and 0.5 Eu/ml.min for grey bone char and white bone char, respectively. The efficency of the process was found eighty percent. Primary concentration of basic compounds had no effect on endotoxin removal rate. Therefore, endotoxin removal kinetic of reaction is a zero order reaction. This study revealed that ozonation process using bone char is more efficient than other proposed methods such as ozonation or chlorination and can be used successfully for endotoxin removal from water as a efficient method.

Removal of Fluoride from Drinking Water Using Modified Immobilized Activated Alumina

Directory of Open Access Journals (Sweden)

Aneeza Rafique

2013-01-01

Full Text Available The study describes the removal of fluoride from drinking water using modified immobilized activated alumina (MIAA prepared by sol-gel method. The modification was done by adding a specific amount of alum during the sol formation step. The fluoride removal efficiency of MIAA was 1.35 times higher as compared to normal immobilized activated alumina. A batch adsorption study was performed as a function of adsorbent dose, contact time, stirring rate, and initial fluoride concentration. More than 90% removal of fluoride was achieved within 60 minutes of contact time. The adsorption potential of MIAA was compared with activated charcoal which showed that the removal efficiency was about 10% more than the activated charcoal. Both the Langmuir and Freundlich adsorption isotherms fitted well for the fluoride adsorption on MIAA with the regression coefficient R2 of 0.99 and 0.98, respectively. MIAA can both be regenerated thermally and chemically. Adsorption experiments using MIAA were employed on real drinking water samples from a fluoride affected area. The study showed that modified immobilized activated alumina is an effective adsorbent for fluoride removal.

Slow neutron scattering by water molecules

Energy Technology Data Exchange (ETDEWEB)

Stancic, V [Boris Kidric Institute of Nuclear Sciences Vinca, Beograd (Yugoslavia)

1970-07-01

In this work some new, preliminary formulae for slow neutron scattering cross section calculation by heavy and light water molecules have been done. The idea was to find, from the sum which exists in well known Nelkin model, other cross sections in a more simple analytical form, so that next approximations may be possible. In order to sum a series it was starting from Euler-Mclaurin formula. Some new summation formulae have been derived there, and defined in two theorems. Extensive calculations, especially during the evaluation of residues, have been made at the CDC 3600 computer. validation of derived formulae was done by comparison with the BNL-325 results. Good agreement is shown. (author)

Slow neutron scattering by water molecules

International Nuclear Information System (INIS)

Stancic, V.

1970-01-01

In this work some new, preliminary formulae for slow neutron scattering cross section calculation by heavy and light water molecules have been done. The idea was to find, from the sum which exists in well known Nelkin model, other cross sections in a more simple analytical form, so that next approximations may be possible. In order to sum a series it was starting from Euler-Mclaurin formula. Some new summation formulae have been derived there, and defined in two theorems. Extensive calculations, especially during the evaluation of residues, have been made at the CDC 3600 computer. validation of derived formulae was done by comparison with the BNL-325 results. Good agreement is shown. (author)

Measurements of water molecule density by tunable diode laser absorption spectroscopy in dielectric barrier discharges with gas-water interface

Science.gov (United States)

Tachibana, Kunihide; Nakamura, Toshihiro; Kawasaki, Mitsuo; Morita, Tatsuo; Umekawa, Toyofumi; Kawasaki, Masahiro

2018-01-01

We measured water molecule (H2O) density by tunable diode-laser absorption spectroscopy (TDLAS) for applications in dielectric barrier discharges (DBDs) with a gas-water interface. First, the effects of water temperature and presence of gas flow were tested using a Petri dish filled with water and a gas injection nozzle. Second, the TDLAS system was applied to the measurements of H2O density in two types of DBDs; one was a normal (non-inverted) type with a dielectric-covered electrode above a water-filled counter electrode and the other was an inverted type with a water-suspending mesh electrode above a dielectric-covered counter electrode. The H2O density in the normal DBD was close to the density estimated from the saturated vapor pressure, whereas the density in the inverted DBD was about half of that in the former type. The difference is attributed to the upward gas flow in the latter type, that pushes the water molecules up towards the gas-water interface.

Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment

Science.gov (United States)

Abebe, Lydia S.; Chen, Xinyu; Sobsey, Mark D.

2016-01-01

The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI) between 4.7 (±1.56) and 7.5 (±0.02) log10 for Escherichia coli, and between 2.8 (±0.10) and 4.5 (±1.04) log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities turbidity standards of the US EPA and guidance by the World Health Organization (WHO). According to WHO health-based microbial removal targets for household water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions. PMID:26927152

Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment

Directory of Open Access Journals (Sweden)

Lydia S. Abebe

2016-02-01

Full Text Available The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI between 4.7 (±1.56 and 7.5 (±0.02 log10 for Escherichia coli, and between 2.8 (±0.10 and 4.5 (±1.04 log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities < 1 NTU, which meet turbidity standards of the US EPA and guidance by the World Health Organization (WHO. According to WHO health-based microbial removal targets for household water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

Ground water pollution by arsenic and its effects on health. Removal of arsenic from water; Suichu karano hiso no jokyo gijutsu

Energy Technology Data Exchange (ETDEWEB)

Tokunaga, S.

1997-07-10

Recently environmental standard for ground water is established. It is pointed out that the need of arsenic`s removal from water is expected in high level. Present condition of removal techniques of inorganic nitrogen and problems are explained. For example, ferro (III) chloride method is effective in As(V) and most suitable range is pH4{approx}5. Removal is possible until 0.005 when initial concentration is 0.2 mg{center_dot}l{sup -1}. As far as secondary problems are, there are dry treatment of generated sludge and disposal. Earth adsorbent as a new adsorbent is adsorption method is expected. Lanthanum and yttrium compounds possess adsorption for As(III) and As(V) and re-generation use is also possible. For example, removal of As(V) with initial concentration 19 mg{center_dot}l{sup -1} until 0.01 is possible at pH5{approx}77 range when hydroxide lanthanum is used as an adsorbent. Further special characteristics of each method are explained. It is concluded that a good removal method should be selected by considering raw water`s quality, capacity of treatment water, use of treatment water and economics. 29 refs., 2 figs.

STICKING OF MOLECULES ON NONPOROUS AMORPHOUS WATER ICE

Energy Technology Data Exchange (ETDEWEB)

He, Jiao; Vidali, Gianfranco [Physics Department, Syracuse University, Syracuse, NY 13244 (United States); Acharyya, Kinsuk, E-mail: gvidali@syr.edu [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States)

2016-05-20

Accurate modeling of physical and chemical processes in the interstellar medium (ISM) requires detailed knowledge of how atoms and molecules adsorb on dust grains. However, the sticking coefficient, a number between 0 and 1 that measures the first step in the interaction of a particle with a surface, is usually assumed in simulations of ISM environments to be either 0.5 or 1. Here we report on the determination of the sticking coefficient of H{sub 2}, D{sub 2}, N{sub 2}, O{sub 2}, CO, CH{sub 4}, and CO{sub 2} on nonporous amorphous solid water. The sticking coefficient was measured over a wide range of surface temperatures using a highly collimated molecular beam. We showed that the standard way of measuring the sticking coefficient—the King–Wells method—leads to the underestimation of trapping events in which there is incomplete energy accommodation of the molecule on the surface. Surface scattering experiments with the use of a pulsed molecular beam are used instead to measure the sticking coefficient. Based on the values of the measured sticking coefficient, we suggest a useful general formula of the sticking coefficient as a function of grain temperature and molecule-surface binding energy. We use this formula in a simulation of ISM gas–grain chemistry to find the effect of sticking on the abundance of key molecules both on grains and in the gas phase.

performance of water filters towards the removal of selected

African Journals Online (AJOL)

Morohani Merinyo

sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% ... associated diseases in developing countries ... The main drinking water risks in developing ... Tanzania Demographic and Health Survey.

Development of iron-based nanoparticles for Cr(VI removal from drinking water

Directory of Open Access Journals (Sweden)

Vourlias G.

2013-01-01

Full Text Available A great deal of research over recent decades has been motivated by the requirement to lower the concentration of chromium in drinking water. This study has been conducted to determine the feasibility of iron-based nanoparticles for chromium removal from contaminated water. Single Fe, Fe3O4 and binary Fe/Fe3O4 nanoparticles were grown at the 45-80 nm size range using the solar physical vapor deposition technique and tested as potential hexavalent chromium removing agents from aqueous solutions. Due to their higher electron donation ability compared to the Fe3O4 ones, single Fe nanoparticles exhibited the highest Cr(VI removal capacity of more than 3 µg/mg while maintaining a residual concentration 50 µg/L, equal to the regulation limit for drinking water. In combination to their facile and fast magnetic separation, the applicability of the studied particles in water treatment facilities should be considered.

USE OF SYNTHETIC ZEOLITES FOR ARSENATE REMOVAL FROM POLLUTANT WATER

Science.gov (United States)

Arsenic is known to be a hazardous contaminant in drinking water that causes arsenical dermatitis and skin cancer. In the present work, the potential use of a variety of synthetic zeolites for removal of arsenic from water below the current and proposed EPA MCL has been examined...

Aluminum-Based Water Treatment Residue Reuse for Phosphorus Removal

Directory of Open Access Journals (Sweden)

Lai Yoke Lee

2015-04-01

Full Text Available Aluminum-based water treatment residue (Al-WTR generated during the drinking water treatment process is a readily available recycled material with high phosphorus (P adsorption capacity. The P adsorption capacity of Al-WTR generated from Singapore’s water treatment plant was evaluated with reference to particle size range, adsorption pH and temperature. Column tests, with WTR amendments in sand with and without compost, were used to simulate the bioretention systems. The adsorption rate decreased with increasing WTR sizes. Highest P adsorption capacity, 15.57 mg PO43−-P/g WTR, was achieved using fine WTR particles (>50% particles at less than 0.30 mm. At pH 4, the contact time required to reduce effluent P concentration to below the detectable range was half compared with pH 7 and 9. The adsorption rate observed at 40 ± 2 °C was 21% higher compared with that at 30 ± 2 °C. Soil mixes amended with 10% WTR and compost were able to maintain consistently high (90% total phosphorus (TP removal efficiency at a TP load up to 6.45 g/m3. In contrast, TP removal efficiencies associated with columns without WTR amendment decreased to less than 45% as the TP load increased beyond 4.5 g/m3. The results showed that WTR application is beneficial for enhanced TP removal in bioretention systems.

Evaluating the Performance of Iron Nano-particle Resin in Removing Fluoride from Water

Directory of Open Access Journals (Sweden)

Amir Hossein Mahvi

2011-01-01

Full Text Available Excessive amounts of fluoride in drinking water pose serious health problems. It is, therefore, essential to remove it from drinking water by appropriate water treatment processes down to standard levels for preventing the health risks associated. The aim of this study was to determine the performance of a kind of hybrid sorbent resin in removing fluoride from water. Batch experiments were performed to investigate adsorption isotherms and the effects of experimental parameters such as contact time (5-120 min and pH (3-9. Results revealed that fluoride adsorption rate was initially rapid but continued at a slower rate before it reached equilibrium in 120 min. Optimum fluoride removal was observed at a pH range of 3-5.5. The data obtained from the experiments were fitted with Langmiur model.

Removal of arsenic from drinking water by natural adsorbents

OpenAIRE

MD SHAHNOOR ALAM KHAN

2017-01-01

The presence of arsenic in groundwater has been reported in many countries across the world and it is a serious threat to public health. The aim of this study was to identify prospective natural materials with high arsenic adsorption capacity and durable hydraulic property to produce adequate flow of water. The comparative study identified Skye sand as the best natural adsorbent. The prototype household filter with Skye sand achieved complete removal of arsenic and iron. Arsenic removal by du...

Sorbents for phosphate removal from agricultural drainage water

DEFF Research Database (Denmark)

Lyngsie, Gry

Subsurface transport of phosphate (P) from fertilized agricultural fields to freshwaters may lead to eutrophication and reduced biodiversity in inland waters. Mitigation of eutrophic waters is difficult and costly. Reduction of P export to surface waters using filters installed in agricultural...... drains comprising P sorbing materials (PSM) may be a more efficient and cost-effective way to improve water quality. Several materials have been proposed as PSMs for use for cleaning agricultural drainage water. The objective of the present study was to provide data on sorption behavior among a variety...... of PSMs in order to select a material that can quickly remove P from runoff water at both base and peak flow. This was done by screening 15 “local” PSMs’ for their ability to sorb and retain low orthophosphate concentrations (0-161 µM) at short equilibration time (

Membrane Bioprocesses for Pharmaceutical Micropollutant Removal from Waters

Directory of Open Access Journals (Sweden)

Matthias de Cazes

2014-10-01

Full Text Available The purpose of this review work is to give an overview of the research reported on bioprocesses for the treatment of domestic or industrial wastewaters (WW containing pharmaceuticals. Conventional WW treatment technologies are not efficient enough to completely remove all pharmaceuticals from water. Indeed, these compounds are becoming an actual public health problem, because they are more and more present in underground and even in potable waters. Different types of bioprocesses are described in this work: from classical activated sludge systems, which allow the depletion of pharmaceuticals by bio-degradation and adsorption, to enzymatic reactions, which are more focused on the treatment of WW containing a relatively high content of pharmaceuticals and less organic carbon pollution than classical WW. Different aspects concerning the advantages of membrane bioreactors for pharmaceuticals removal are discussed, as well as the more recent studies on enzymatic membrane reactors to the depletion of these recalcitrant compounds.

Kinetics of trace metal removal from tidal water by mangrove sediments under different redox conditions

International Nuclear Information System (INIS)

Suzuki, K.N.; Machado, E.C.; Machado, W.; Bellido, A.V.B.; Bellido, L.F.; Osso, J.A.; Lopes, R.T.

2014-01-01

The extent in which redox conditions can affect the removal kinetics of 58 Co and 65 Zn from tidal water by mangrove sediments was evaluated in microcosm experiments, simulating a tidal flooding period of 6 h. The average half-removal time (t 1/2 ) of 58 Co from overlaying water was slightly higher (7.3 h) under an N 2 -purged water column than under an aerated water column (5.4 h). A lower difference was found for 65 Zn (1.9 h vs. 1.5 h, respectively). Average removals of 58 Co activities from water were 54.6% (N 2 treatment) and 43.5% (aeration treatment), whereas these values were 88.0% and 92.7% for 65 Zn, respectively. Very contrasting sorption kinetics of different radiotracers occurred, while more oxidising conditions favoured only a slightly higher removal. Average 58 Co and 65 Zn inventories within sediments were 30.4% and 18.8% higher in the aeration treatment, respectively. A stronger particle-reactive behaviour was found for 65 Zn that was less redox-sensitive and more efficiently removed by sediments than 58 Co. - Highlights: ► Radiotracer experiments evidenced the role of mangrove sediments in trapping trace metals. ► Very contrasting removal kinetics from tidal water were observed for 65 Zn and 58 Co. ► Nearly 40%–50% of 58 Co activities and nearly 90% of 65 Zn activities in overlying water were removed. ► 65 Zn showed a stronger particle-reactive behaviour than observed for 58 Co. ► 58 Co was more sensitive to redox conditions in tidal water than observed for 65 Zn

The mechanism of 2-dimensional manipulation of DNA molecules by water and ethanol flows

International Nuclear Information System (INIS)

Shen Zigang; Huang Yibo; Li Bin; Zhang Yi

2007-01-01

Due to its unique physical and chemical properties, DNA has recently become a promising material for building blocks in nanofabrication. Many researches focus on how to use DNA molecules as a template for nanowires. Molecular Combing technique is one of important methods to manipulate DNA molecules by using a water meniscus and form specific DNA nano-structures on surfaces. In this paper, by employing a modified molecular combing technique, special patterns of DNA molecules was formed, and the interaction between liquid flows or meniscus and DNA molecules was analyzed, and the mechanism of manipulating DNA molecules by liquid was studied. (authors)

Nitrogen removal and greenhouse gas emissions from constructed wetlands receiving tile drainage water.

Science.gov (United States)

Groh, Tyler A; Gentry, Lowell E; David, Mark B

2015-05-01

Loss of nitrate from agricultural lands to surface waters is an important issue, especially in areas that are extensively tile drained. To reduce these losses, a wide range of in-field and edge-of-field practices have been proposed, including constructed wetlands. We re-evaluated constructed wetlands established in 1994 that were previously studied for their effectiveness in removing nitrate from tile drainage water. Along with this re-evaluation, we measured the production and flux of greenhouse gases (GHGs) (CO, NO, and CH). The tile inlets and outlets of two wetlands were monitored for flow and N during the 2012 and 2013 water years. In addition, seepage rates of water and nitrate under the berm and through the riparian buffer strip were measured. Greenhouse gas emissions from the wetlands were measured using floating chambers (inundated fluxes) or static chambers (terrestrial fluxes). During this 2-yr study, the wetlands removed 56% of the total inlet nitrate load, likely through denitrification in the wetland. Some additional removal of nitrate occurred in seepage water by the riparian buffer strip along each berm (6.1% of the total inlet load, for a total nitrate removal of 62%). The dominant GHG emitted from the wetlands was CO, which represented 75 and 96% of the total GHG emissions during the two water years. The flux of NO contributed between 3.7 and 13% of the total cumulative GHG flux. Emissions of NO were 3.2 and 1.3% of the total nitrate removed from wetlands A and B, respectively. These wetlands continue to remove nitrate at rates similar to those measured after construction, with relatively little GHG gas loss. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Synthesis and characterization of iron nano particles for the arsenic removal in water

International Nuclear Information System (INIS)

Gutierrez M, O. E.

2011-01-01

The synthesis of iron nanoparticles for the removal of metallic ions in polluted waters has been during the last years study topic for different world organizations. This work presents a synthesis method of conditioned coal with iron nanoparticles starting from the use of leaves of pineapple crown, with the purpose of using it in arsenic removal processes in aqueous phase. For the synthesis of this material, the leaves of the pineapple crown were used like supports structure of the iron nanoparticles. First, the pyrolysis appropriate temperature was determined. For the preparation of the support material, this had contact with a ferric nitrate and hexamine solution, because the preparation of the material and the coal synthesis were realized during the pyrolysis process, where the hexamine molecules and the ferric nitrate react, causing the reduction of the iron particles and their dispersion on the support material, obtaining as product a conditioned coal with iron nanoparticles. For the characterization of the materials were used techniques as: Scanning electron microscopy, Transmission electron microscopy, X-Rays Diffraction), X-Ray photoelectron spectroscopy and Moessbauer spectroscopy; moreover was determined the isoelectric point and the density of surface sites. The arsenic sorption capacity of the materials was evaluated by means of the methodology type lots where was determined the sorption kinetics and isotherms in terms of arsenic concentration and mass. (Author)

Biological nitrate removal processes from drinking water supply-a review.

Science.gov (United States)

Mohseni-Bandpi, Anoushiravan; Elliott, David Jack; Zazouli, Mohammad Ali

2013-12-19

This paper reviews both heterotrophic and autotrophic processes for the removal of nitrate from water supplies. The most commonly used carbon sources in heterotrophic denitrification are methanol, ethanol and acetic acid. Process performance for each feed stock is compared with particular reference nitrate and nitrite residual and to toxicity potential. Autotrophic nitrate removal has the advantages of not requiring an organic carbon source; however the slow growth rate of autotrophic bacteria and low nitrate removal rate have contributed to the fact that relatively few full scale plants are in operation at the present time.

Graphene oxide/ferric hydroxide composites for efficient arsenate removal from drinking water

International Nuclear Information System (INIS)

Zhang Kai; Dwivedi, Vineet; Chi Chunyan; Wu Jishan

2010-01-01

A series of novel composites based on graphene oxide (GO) cross-linked with ferric hydroxide was developed for effective removal of arsenate from contaminated drinking water. GO, which was used as a supporting matrix here, was firstly treated with ferrous sulfate. Then, the ferrous compound cross-linked with GO was in situ oxidized to ferric compound by hydrogen peroxide, followed by treating with ammonium hydroxide. The morphology and composition of the composites were analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The ferric hydroxide was found to be homogenously impregnated onto GO sheets in amorphous form. These composites were evaluated as absorbents for arsenate removal from contaminated drinking water. For the water with arsenate concentration at 51.14 ppm, more than 95% of arsenate was absorbed by composite GO-Fe-5 with an absorption capacity of 23.78 mg arsenate/g of composite. Effective arsenate removal occurred in a wide range of pH from 4 to 9. However, the efficiency of arsenate removal was decreased when pH was increased to higher than 8.

Fluoride Removal From Drinking Water by Electrocoagulation Using Iron and Aluminum Electrodes

Directory of Open Access Journals (Sweden)

Takdastan

2014-07-01

Full Text Available Background Existence of fluoride in drinking water above the permissible level causes human skeletal fluorosis. Objectives Electrocoagulation by iron and aluminum electrodes was proposed for removing fluoride from drinking water. Materials and Methods Effects of different operating conditions such as treatment time, initial pH, applied voltage, type and number of electrodes, the spaces between aluminum and iron electrodes, and energy consumption during electrocoagulation were investigated in the batch reactor. Variable concentrations of fluoride solution were prepared by mixing proper amounts of sodium fluoride with deionized water. Results Experimental results showed that aluminum electrode is more effective in fluoride removal than iron, as in 40 minutes and initial pH of 7.5 at 20 V, the fluoride removal process reached to 97.86%. The final recommendable limit of fluoride (1.5 mg/L was obtained in 10 minutes at 20 V with the aluminum electrode. Conclusions In electrocoagulation with iron and aluminum electrodes, increase of voltage, number of electrodes and reaction time as well as decrease of the spaces between electrodes, enhanced the fluoride removal efficiency from drinking water. In addition the effect of pH and initial concentration of fluoride varied with types of electrodes.

Facile synthesis of Cu(II) impregnated biochar with enhanced adsorption activity for the removal of doxycycline hydrochloride from water.

Science.gov (United States)

Liu, Su; Xu, Wei-Hua; Liu, Yun-Guo; Tan, Xiao-Fei; Zeng, Guang-Ming; Li, Xin; Liang, Jie; Zhou, Zan; Yan, Zhi-Li; Cai, Xiao-Xi

2017-08-15

In this study, the effect factors and mechanisms of doxycycline hydrochloride (DOX) adsorption on copper nitrate modified biochar (Cu-BC) was investigated. Cu-BC absorbent was synthesized through calcination of peanut shells biomass at 450°C and then impregnation with copper nitrate. The Cu-BC has exhibited excellent sorption efficiency about 93.22% of doxycycline hydrochloride from aqueous solution, which was double higher than that of the unmodified biochar. The experimental results suggest that the adsorption efficiency of DOX on the Cu-BC is dominated by the strong complexation, electrostatic interactions between DOX molecules and the Cu-BC samples. Comprehensively considering the cost, efficiency and the application to realistic water, the Cu-BC hold the significant potential for enhancing the effectiveness to remove DOX from water. Copyright © 2017 Elsevier B.V. All rights reserved.

Removal of emerging perfluorooctanoic acid and perfluorooctane sulfonate contaminants from lake water.

Science.gov (United States)

Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Sarker, Dipok Chandra; Suja, Fatihah

2017-08-01

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the major polyfluoroalkyl substances (PFASs) contaminating global water environment. This study investigated the efficiency of granular activated carbon (GAC), ultrafiltration (UF) and nanofiltration (NF) treatment for removing PFOS and PFOA contaminants from lake water. NF gave greater removal of all contaminant types (in terms of organic matter, PFOS and PFOA) than GAC treatment which in turn was greater than UF treatment. The lower removal by UF was due to larger pore size of the membrane compared to the size of the target contaminants. For all treatment processes, lower pH (4) in the feedwater showed greater rejection of the organics and selected PFASs. This was likely due to increase in the electrostatic repulsion between solute and sorbent. It could be observed that on increasing the concentration of organics in the feed solution, the rejection of PFOA/PFOS decreased which was due to competition between organics and PFOS/PFOA for binding sites on the membrane/activated carbon surface. It was also noted that protein content led to greater influence for lower rejection of the PFOA/PFOS than carbohydrate or DOC content. This study demonstrated the potential use of membrane processes for removing emerging persistent organic pollutant removal from lake water.

Comparison of Water Turbidity Removal Efficiencies of Descurainia Sophia Seed Extract and Ferric chloride

Directory of Open Access Journals (Sweden)

Mazyar Peyda

2016-03-01

Full Text Available Background Turbidity removal using inorganic coagulants such as iron and aluminum salts in water treatment processes causes environmental and human health concern. Historically, the use of natural coagulant to purify turbid water has been practiced for a long time. Recent research indicates that Descurainia Sophia seed can be effectively used as a natural coagulant to remove water turbidity. Method: In this work, turbidity removal efficiency of Descurainia Sophia seed extract was compared with Ferric chloride. Experiments were performed in laboratory scale. The coagulation experiments were done with kaolin as a model soil to produce turbidity in distilled water. The turbidity removal efficiency of Descurainia Sophia seed extract and Ferric chloride were conducted with jar test apparatus. In all experiments, initial turbidity was kept constant 100(NTU. Optimum combination of independent variables was used to compare two different types of coagulants. Result: The obtained results showed that Ferric chloride could remove 89.75% of the initial turbidity, while in case of Descurainia Sophia this value was 43.13%. The total organic carbon (TOC analysis of the treated water using seed extract showed an increased concentration of TOC equal to 0.99 mg/L. Conclusions: This research has shown that Descurainia Sophia seed extract has an acceptable potential in the coagulation/flocculation process to treat turbid water.

Removal of Sulfate from Waste Water by Activated Carbon

OpenAIRE

Mohammed Sadeq Salman

2009-01-01

Activated carbon was Produced from coconut shell and was used for removing sulfate from industrial waste water in batch Processes. The influence of various parameter were studied such as pH (4.5 9.) , agitation time (0 120)min and adsorbent dose (2 10) gm.The Langmuir and frandlich adsorption capacity models were been investigated where showed there are fitting with langmmuir model with squre regression value ( 0.76). The percent of removal of sulfate (22% - 38%) at (PH=7) in the isotherm ...

Removal of phenol from water : a comparison of energization methods

NARCIS (Netherlands)

Grabowski, L.R.; Veldhuizen, van E.M.; Rutgers, W.R.

2005-01-01

Direct electrical energization methods for removal of persistent substances from water are under investigation in the framework of the ytriD-project. The emphasis of the first stage of the project is the energy efficiency. A comparison is made between a batch reactor with a thin layer of water and

Physico-chemical forms of natural radionuclides in drilled well waters and their removal by ion exchange

International Nuclear Information System (INIS)

Vaaramaa, K.

2003-01-01

Appreciable concentrations of natural uranium and its daughter radionuclides may occur in drinking water obtained from drilled wells when the bedrock contains these nuclides. Effective methods are needed to remove these radionuclides. A wide range of ion exchange materials, both organic and inorganic, were evaluated for the removal of 234,238 U, 226 Ra, 210 Po and 210 Pb from ground waters. Screenin tests were carried out, in which distribution coefficients (KD) were determined for the ion exchangers. The ion exchangers that gave the highest KD's were tested in column-mode experiments for the removal of the radionuclides from drilled well water. The most efficient exchanger for the removal of U from neutral and slightly alkaline waters was the strong base anion resin. The chelating aminophosphonate resin removed uranium very efficiently from slightly acidic water. As well, it was an efficient exchanger for the removal of toxic and harmful transition metals from drilled well waters. The strong and weak acid cation resins and zeolite A removed radium most efficiently. Large fractions of the total activity of polonium and lead were found to adsorb on equipment in the ion exchange studies. In investigation of this, the well waters were filtered through membranes to determine the soluble and particle-bound forms of 234,238 U, 226 Ra, 210 Po and 210 Pb. Eight of the waters were of Ca type and two were of Na-Cl type. Some of the waters also had high concentrations of Fe, Mn and humic substances. Uranium was present entirely in soluble form, probably as uranyl ion in soluble carbonate complexes. 226 Ra was in soluble form in the waters with low concentrations of Fe and Mn, but 10% of the total radium activity was bound to particles in Fe-Mn-rich waters. The speciation of Po is complex in natural waters; polonium was present in both soluble and particle-bound forms. A correlation was observed between the fractions of particle-bound 210 Po and the concentrations of iron in

Removal of Perfluorinated Compounds From Water using Nanoscale Zero-Valent Iron

DEFF Research Database (Denmark)

Arvaniti, Olga S.; Hwang, Yuhoon; Andersen, Henrik Rasmus

Perfluorinated Compounds (PFCs) are persistent micropollutants that have been detected in various environmental and biological matrices, worldwide. During the last decade, these compounds have also been detected in municipal wastewater and tap water. Due to the stability of C-F bond......, the application of biological and conventional physicochemical treatment methods does not seem to remove sufficient these compounds from water and wastewater. In the current study, the removal efficiency of four PFCs using three different types of nanoscale zero-valent iron (nZVI) was investigated. Influencing...... factors such as, initial pH solution, reaction temperature and nZVI dosage were also studied. According to the results, target compounds were removed in the presence of chemically synthesized nZVI modified with Mg-aminoclay (MgAC) than under commercial iron powder and chemically synthesized uncoated n...

Novel flow-through bioremediation system for removing nitrate from nursery discharge water.

Science.gov (United States)

Chris Wilson, P; Albano, Joseph P

2013-11-30

Nitrate losses in surface runoff water from nursery production areas can be significant. This study evaluated the potential use of microbial-based (denitrification), flow-through bioreactors for their nitrate-remediation ability. Duplicate bioreactor systems were constructed at a local foliage plant nursery. Each bioreactor system consisted of four 242 L tanks with connections alternating between bottom and top. Each tank was filled with approximately 113 L of Kaldness media to provide surface area for attachment of native microflora. Molasses was supplied as a carbon source for denitrification and water flow rates through the systems ranged from 5 to 18 L min(-1) during tests. Automatic water samplers were used to collect composite samples every 15 min from both the inflow and the exit flow water. Results indicate consistent removal of 80-100% of the nitrate flowing into the systems. Accumulation of ammoniacal and nitrite nitrogen did not occur, indicating that the nitrate-nitrogen was removed from the water, and not simply transformed into another water-soluble species. Occasions where removal rates were less than 80% were usually traced to faulty delivery of the carbon source. Results indicate that modular microbial-based bioremediation systems may be a useful tool for helping water managers meet stringent nitrogen water quality regulations, especially at nurseries with limited space for expansion of water retention facilities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ozone-assisted Regeneration of Magnetic Carbon Nanotubes for Removing Organic Water Pollutants

DEFF Research Database (Denmark)

Ateia, Mohamed; Ceccato, Marcel; Budi, Akin

2018-01-01

(MCNTs) after they have been used to remove organic pollutants from water. We ran MCNT through multiple regeneration cycles (i.e. magnetic collection → ozone regeneration → washing with ethanol then water) to adsorb atrazine. The results of our adsorption experiments show that the atrazine removal...... consecutive regeneration cycles. Additionally, we used a three layer graphite slab as a model system for CNTs and performed density functional theory (DFT) calculations to determine the free energy of adsorption and the free energy of solvation of atrazine and its byproducts in water and ethanol. The results...

Arsenic removal from water using low-cost adsorbents: A comparative study

Directory of Open Access Journals (Sweden)

Rajaković Ljubinka V.

2011-01-01

Full Text Available Inorganic arsenic removal from water using low-cost adsorbents is presented in this paper. Selective removal of As(III and As(V from water was performed with natural materials (zeolite, bentonite, sepiolite, pyrolusite and limonite and industrial by-products (waste filter sand as a water treatment residual and blast furnace slag from steel production; all inexpensive and locally available. Kinetic and equilibrium studies were realized using batch system techniques under conditions that are likely to occur in real water treatment systems. The natural zeolite and the industrial by-products were found to be good and inexpensive sorbents for arsenic while bentonite and sepiolite clays showed little affinity towards arsenic. The highest maximum sorption capacities were obtained for natural zeolite, 4.07 mg As(V g-1, and waste iron slag, 4.04 mg As(V g-1.

Identification of Carboxylate, Phosphate, and Phenoxide Functionalities in Deprotonated Molecules Related to Drug Metabolites via Ion-Molecule Reactions with water and Diethylhydroxyborane

Science.gov (United States)

Zhu, Hanyu; Ma, Xin; Kong, John Y.; Zhang, Minli; Kenttämaa, Hilkka I.

2017-10-01

Tandem mass spectrometry based on ion-molecule reactions has emerged as a powerful tool for structural elucidation of ionized analytes. However, most currently used reagents were designed to react with protonated analytes, making them suboptimal for acidic analytes that are preferentially detected in negative ion mode. In this work we demonstrate that the phenoxide, carboxylate, and phosphate functionalities can be identified in deprotonated molecules by use of a combination of two reagents, diethylmethoxyborane (DEMB) and water. A novel reagent introduction setup that allowed DEMB and water to be separately introduced into the ion trap region of the mass spectrometer was developed to facilitate fundamental studies of this reaction. A new reagent, diethylhydroxyborane (DEHB), was generated inside the ion trap by hydrolysis of DEMB on introduction of water. Most carboxylates and phenoxides formed a DEHB adduct, followed by addition of one water molecule and subsequent ethane elimination (DEHB adduct +H2O - CH3CH3) as the major product ion. Phenoxides with a hydroxy group adjacent to the deprotonation site and phosphates formed a DEHB adduct, followed by ethane elimination (DEHB adduct - CH3CH3). Deprotonated molecules with strong intramolecular hydrogen bonds or without the aforementioned functionalities, including sulfates, were unreactive toward DEHB/H2O. Reaction mechanisms were explored via isotope labeling experiments and quantum chemical calculations. The mass spectrometry method allowed the differentiation of phenoxide-, carboxylate-, phosphate-, and sulfate-containing analytes. Finally, it was successfully coupled with high-performance liquid chromatography for the analysis of a mixture containing hymecromone, a biliary spasm drug, and its three possible metabolites. [Figure not available: see fulltext.

Application of cellulose nanofibers to remove water-based flexographic inks from wastewaters.

Science.gov (United States)

Balea, Ana; Monte, M Concepción; de la Fuente, Elena; Negro, Carlos; Blanco, Ángeles

2017-02-01

Water-based or flexographic inks in paper and plastic industries are more environmentally favourable than organic solvent-based inks. However, their use also creates new challenges because they remain dissolved in water and alter the recycling process. Conventional deinking technologies such as flotation processes do not effectively remove them. Adsorption, coagulation/flocculation, biological and membrane processes are either expensive or have negative health impacts, making the development of alternative methods necessary. Cellulose nanofibers (CNF) are biodegradable, and their structural and mechanical properties are useful for wastewater treatment. TEMPO-oxidised CNF have been evaluated for the decolourisation of wastewaters that contained copper phthalocyanine blue, carbon black and diarlyide yellow pigments. CNF in combination with a cationic polyacrylamide (cPAM) has also been tested. Jar-test methodology was used to evaluate the efficiency of the different treatments and cationic/anionic demand, turbidity and ink concentration in waters were measured. Results show that dual-component system for ink removal has a high potential as an alternative bio-based adsorbent for the removal of water-based inks. In addition, experiments varying CNF and cPAM concentrations were performed to optimise the ink-removal process. Ink concentration reductions of 100%, 87.5% and 83.3% were achieved for copper phthalocyanine blue, carbon black and diarlyide yellow pigments, respectively. Flocculation studies carried out show the decolourisation mechanism during the dual-component treatment of wastewaters containing water-based inks.

Removal of bacteria and viruses from waters using layered double hydroxide nanocomposites

Directory of Open Access Journals (Sweden)

Song Jin et al

2007-01-01

Full Text Available We have identified synthetic layered double hydroxides (LDH nanocomposites as an effective group of material for removing bacteria and viruses from water. In this study, LDH nanocomposites were synthesized and tested for removing biological contaminants. LDH was used to remove MS2 and X174 (indicator viruses, and Escherichia coli (an indicator bacterium from synthetic groundwater and to remove mixed communities of heterotrophic bacteria from raw river water. Our results indicate that LDH composed of magnesium–aluminium or zinc–aluminium has a viral and bacterial adsorption efficiency ≥99% at viral concentrations between 5.9×106 and 9.1×106 plaque forming units (pfu/L and bacterial concentrations between 1.6×1010 and 2.6×1010 colony forming units (cfu/L when exposed to LDH in a slurry suspension system. Adsorption densities of viruses and bacteria to LDH in suspension ranged from 1.4×1010 to 2.1×1010 pfu/kg LDH and 3.2×1013–5.2×1013 cfu/kg LDH, respectively. We also tested the efficiency of LDH in removing heterotrophic bacteria from raw river water. While removal efficiencies were still high (87–99%, the adsorption capacities of the two kinds of LDH were 4–5 orders of magnitude lower than when exposed to synthetic groundwater, depending on if the LDH was in suspension or a packed column, respectively.

Control of unidirectional transport of single-file water molecules through carbon nanotubes in an electric field.

Science.gov (United States)

Su, Jiaye; Guo, Hongxia

2011-01-25

The transport of water molecules through nanopores is not only crucial to biological activities but also useful for designing novel nanofluidic devices. Despite considerable effort and progress that has been made, a controllable and unidirectional water flow is still difficult to achieve and the underlying mechanism is far from being understood. In this paper, using molecular dynamics simulations, we systematically investigate the effects of an external electric field on the transport of single-file water molecules through a carbon nanotube (CNT). We find that the orientation of water molecules inside the CNT can be well-tuned by the electric field and is strongly coupled to the water flux. This orientation-induced water flux is energetically due to the asymmetrical water-water interaction along the CNT axis. The wavelike water density profiles are disturbed under strong field strengths. The frequency of flipping for the water dipoles will decrease as the field strength is increased, and the flipping events vanish completely for the relatively large field strengths. Most importantly, a critical field strength E(c) related to the water flux is found. The water flux is increased as E is increased for E ≤ E(c), while it is almost unchanged for E > E(c). Thus, the electric field offers a level of governing for unidirectional water flow, which may have some biological applications and provides a route for designing efficient nanopumps.

Removal of aqueous nC60 fullerene from water by low pressure membrane filtration

NARCIS (Netherlands)

Floris, R.; Nijmeijer, K.; Cornelissen, E. R.

2016-01-01

The potential environmental and health risks of engineered nanoparticles such as buckminsterfullerene C60 in water require their removal during the production of drinking water. We present a study focusing on (i) the removal mechanism and (ii) the elucidation of the role of the membrane pore size

Water removal characteristics of parallel serpentine channels

Energy Technology Data Exchange (ETDEWEB)

Jiao, K.; Zhou, B.; Quan, P. [Windsor Univ., ON (Canada). Dept. of Mechanical, Automotive and Materials Engineering

2005-07-01

A study was conducted in which the liquid water behaviours in parallel serpentine channels with manifolds on the cathode side of a proton exchange membrane (PEM) fuel cell stack were examined. A 3-dimensional, unsteady two-phase flow model within the commercial computational fluid dynamics software package FLUENT was used. Membrane electrode assemblies (MEA) were placed on different sides in the numerical analysis. Several water management issues were identified for this type of fuel cell stack by examining the flow behaviours of liquid water and airflow velocity fields. It was shown that water in the outflow manifold could be blocked by air streams from the gas flow channels, with water flowing continuously into the outflow manifold. It was also shown that the pressure drop along all the unit cells can never increase or decrease at the same pace. Water which adheres to the end wall of both the inlet and outlet manifolds is difficult to remove. It was suggested that faster water drainage can be achieved by keeping the MEA side of the gas flow channels close to the outlet of the outflow manifold. It was also suggested that the collecting and separating effect at the serpentine gas flow channels could improve the water drainage. 8 refs., 10 figs.

Evaluating of arsenic(V) removal from water by weak-base anion exchange adsorbents.

Science.gov (United States)

Awual, M Rabiul; Hossain, M Amran; Shenashen, M A; Yaita, Tsuyoshi; Suzuki, Shinichi; Jyo, Akinori

2013-01-01

Arsenic contamination of groundwater has been called the largest mass poisoning calamity in human history and creates severe health problems. The effective adsorbents are imperative in response to the widespread removal of toxic arsenic exposure through drinking water. Evaluation of arsenic(V) removal from water by weak-base anion exchange adsorbents was studied in this paper, aiming at the determination of the effects of pH, competing anions, and feed flow rates to improvement on remediation. Two types of weak-base adsorbents were used to evaluate arsenic(V) removal efficiency both in batch and column approaches. Anion selectivity was determined by both adsorbents in batch method as equilibrium As(V) adsorption capacities. Column studies were performed in fixed-bed experiments using both adsorbent packed columns, and kinetic performance was dependent on the feed flow rate and competing anions. The weak-base adsorbents clarified that these are selective to arsenic(V) over competition of chloride, nitrate, and sulfate anions. The solution pH played an important role in arsenic(V) removal, and a higher pH can cause lower adsorption capacities. A low concentration level of arsenic(V) was also removed by these adsorbents even at a high flow rate of 250-350 h(-1). Adsorbed arsenic(V) was quantitatively eluted with 1 M HCl acid and regenerated into hydrochloride form simultaneously for the next adsorption operation after rinsing with water. The weak-base anion exchange adsorbents are to be an effective means to remove arsenic(V) from drinking water. The fast adsorption rate and the excellent adsorption capacity in the neutral pH range will render this removal technique attractive in practical use in chemical industry.

Application of chitosan/polyacrylamide nanofibres for removal of chromate and phosphate in water

Science.gov (United States)

Nthumbi, Richard M.; Catherine Ngila, J.; Moodley, Brenda; Kindness, Andrew; Petrik, Leslie

Water pollution is an intractable environmental problem in South Africa. Management of the water resource is vital in order to address the water scarcity issues. Research on remediation of contaminated water has focused mainly on the removal of heavy metals such as Pb, Cd, Zn, Hg and Cu and neglected other inorganic pollutants. In this work we focus on the removal of anions, namely chromate and phosphate. Chromium is extensively used in the textile, leather and metallurgy industries and contaminates surface water and groundwater when inadequately treated industrial effluents are discharged. Chromium has been associated with irregular sugar metabolism, nosebleeds and ulcers, and it is also carcinogenic. The phosphate ion is an essential micronutrient responsible for healthy plant growth. However, excess phosphate intake stimulates rapid growth of photosynthetic algae and cyanobacteria, resulting in eutrophication. This phenomenon (algal bloom) causes other organisms to die due to reduced oxygen in the water. In order to offer remediation measures, this study reports the use of electrospun nanofibres for the removal of chromate and phosphate anions. Adsorption experiments were carried out using nanofibres electrospun from chitosan and polyacrylamide polymer blends, cross-linked with glutaraldehyde. Quantification of chromium was done using ICP-OES while UV-Vis spectrophotometry was used for the determination of phosphates. Batch adsorption experiments were done to determine optimum adsorption parameters such as pH, contact time, temperature and initial analyte concentration. Removal of the ions using a flow-adsorption technique through a micro-column was performed. The experimental data obtained were analysed using Langmuir and Freundlich models to study the adsorption mechanisms. The nanofibres had an adsorption capacity for Cr(VI) and PO43- of 0.26 mg g-1 and 392 mg g-1, respectively, and removal efficiencies of 93% and 97.4%, in the same order, in synthetic water

Removal of arsenic species from drinking water by Iranian natural and synthetic zeolites

International Nuclear Information System (INIS)

Menhaje-Bena, R.; Kazemian, H.; Shahtaheri, S.J.; Ghazi-Khansari, M.

2003-01-01

The main objective of this study was to find a relatively inexpensive method for removal of arsenic species from drinking water. The uptake capability of Iron (II) modified natural clinoptilolites and relevant synthetic zeolites A and P was investigated toward inorganic arsenic species from drinking water. Results obtained from sorption experiments, using a batch (static) technique showed that, among the investigated zeolites, modified synthetic zeolite A was the most selective sorbent for removal of arsenate and arsenite from drinking water. Through this study the influencing of factories including temperature, concentration, pH, particle size and interferences was evaluated on removal of arsenic species. The synthetic zeolites and their modified forms were also characterized, using XRD, XRF and thermal analysis techniques. (authors)

Treatment techniques for removing natural radionuclides from drinking water. Final report of the TENAWA project

International Nuclear Information System (INIS)

Annanmaeki, M.; Turtiainen, T.

2000-01-01

TENAWA project (Treatment Techniques for Removing Natural Radionuclides from Drinking Water) was carried out on a cost-shared basic with the European Commission (CEC) under the supervision of Directorate-General XII, Radiation Protection Unit. TENAWA project was started because in several European countries ground water supplies may contain high amounts of natural radionuclides. During the project both laboratory and field research was performed in order to test the applicability of different equipment and techniques for removing natural radionuclides from drinking water. The measurable objectives of the project were: to give recommendations on the most suitable methods for removing radon ( 222 Rn), uranium ( 238,234 U), radium ( 226 , 228 Ra), lead ( 210 Pb) and polonium ( 210 Po) from drinking water of different qualities (i.e. soft, hard, iron-, manganese- and humus-rich, acidic) to test commercially available equipment for its ability to remove radionuclides; to find new materials, absorbents and membranes effective in the removal of radionuclides and to issue guidelines for the treatment and disposal of radioactive wastes produced in water treatment. Radon could be removed efficiently (>95%) from domestic water supplies by both aeration and granular activated carbon (GAC) filtration. Defects in technical reliability or radon removal efficiency were observed in some aerators. The significant drawback of GAC filtration was the elevated gamma dose rates (up to 120 μSv/h) near the filter and the radioactivity of spent GAC. Aeration was found to be a suitable method for removing radon at waterworks, too. The removal efficiencies at waterworks where the aeration process was designed to remove radon or carbon dioxide were 67-99%. If the aeration process was properly designed, removal efficiencies higher than 95% could be attained. Uranium could best be removed (>95%) with strong basic anion exchange resins and radium by applying strong acidic cation exchange resins

Treatment techniques for removing natural radionuclides from drinking water. Final report of the TENAWA project

Energy Technology Data Exchange (ETDEWEB)

Annanmaeki, M.; Turtiainen, T. [eds.

2000-01-01

TENAWA project (Treatment Techniques for Removing Natural Radionuclides from Drinking Water) was carried out on a cost-shared basic with the European Commission (CEC) under the supervision of Directorate-General XII, Radiation Protection Unit. TENAWA project was started because in several European countries ground water supplies may contain high amounts of natural radionuclides. During the project both laboratory and field research was performed in order to test the applicability of different equipment and techniques for removing natural radionuclides from drinking water. The measurable objectives of the project were: to give recommendations on the most suitable methods for removing radon ({sup 222}Rn), uranium ({sup 238,234}U), radium ({sup 226}, {sup 228}Ra), lead ({sup 210}Pb) and polonium ({sup 210}Po) from drinking water of different qualities (i.e. soft, hard, iron-, manganese- and humus-rich, acidic) to test commercially available equipment for its ability to remove radionuclides; to find new materials, absorbents and membranes effective in the removal of radionuclides and to issue guidelines for the treatment and disposal of radioactive wastes produced in water treatment. Radon could be removed efficiently (>95%) from domestic water supplies by both aeration and granular activated carbon (GAC) filtration. Defects in technical reliability or radon removal efficiency were observed in some aerators. The significant drawback of GAC filtration was the elevated gamma dose rates (up to 120 {mu}Sv/h) near the filter and the radioactivity of spent GAC. Aeration was found to be a suitable method for removing radon at waterworks, too. The removal efficiencies at waterworks where the aeration process was designed to remove radon or carbon dioxide were 67-99%. If the aeration process was properly designed, removal efficiencies higher than 95% could be attained. Uranium could best be removed (>95%) with strong basic anion exchange resins and radium by applying strong

Subsurface iron and arsenic removal for drinking water treatment in Bangladesh

NARCIS (Netherlands)

Van Halem, D.

2011-01-01

Arsenic contamination of shallow tube well drinking water is an urgent health problem in Bangladesh. Current arsenic mitigation solutions, including (household) arsenic removal options, do not always provide a sustainable alternative for safe drinking water. A novel technology, Subsurface Arsenic

The effect of magnesium on partial sulphate removal from mine water as gypsum.

Science.gov (United States)

Tolonen, Emma-Tuulia; Rämö, Jaakko; Lassi, Ulla

2015-08-15

The aim of this research was to investigate the effect of magnesium on the removal efficiency of sulphate as gypsum from mine water. The precipitation conditions were simulated with MINEQL + software and the simulation results were compared with the results from laboratory jar test experiments. Both the simulation and the laboratory results showed that magnesium in the mine water was maintaining sulphate in a soluble form as magnesium sulphate (MgSO4) at pH 9.6. Thus magnesium was preventing the removal of sulphate as gypsum (CaSO4·2H2O). However, change in the lime precipitation pH from 9.6 to 12.5 resulted in magnesium hydroxide (Mg(OH)2) precipitation and improved sulphate removal. Additionally, magnesium hydroxide could act as seed crystals for gypsum precipitation or co-precipitate sulphate further enhancing the removal of sulphate from mine water. Copyright © 2015 Elsevier Ltd. All rights reserved.

Can Microalgae Remove Pharmaceutical Contaminants from Water?

Science.gov (United States)

Xiong, Jiu-Qiang; Kurade, Mayur B; Jeon, Byong-Hun

2018-01-01

The increase in worldwide water contamination with numerous pharmaceutical contaminants (PCs) has become an emerging environmental concern due to their considerable ecotoxicities and associated health issues. Microalgae-mediated bioremediation of PCs has recently gained scientific attention, as microalgal bioremediation is a solar-power driven, ecologically comprehensive, and sustainable reclamation strategy. In this review, we comprehensively describe the current research on the possible roles and applications of microalgae for removing PCs from aqueous media. We summarize several novel approaches including constructing microbial consortia, acclimation, and cometabolism for enhanced removal of PCs by microalgae, which would improve practical feasibility of these technologies. Some novel concepts for degrading PCs using integrated processes and genetic modifications to realize algal-based bioremediation technologies are also recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetite nanoparticles coated glass wool for As(V) removal from drinking water

International Nuclear Information System (INIS)

Kango, Sarita; Kumar, Rajesh

2015-01-01

Arsenic (As) removal from contaminated groundwater is a key environmental concern worldwide. In this study, glass wool was coated with magnetite nanoparticles under argon gas flow and magnetite coated glass wool have been investigated for application as an adsorbent for As(V) removal from water. The adsorbent was characterized by using Scanning Electron Microscopy (SEM) and arsenic contaminated water treated with adsorbent was analyzed by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The ICP-MS results showed that 10 g/L of adsorbent removed 99.4% of As(V) within 5 hours at pH-7 and initial arsenic concentration of 360µg/L. Adsorption kinetics data fitted well in pseudo-first-order kinetics model with high correlation coefficient (R 2 = 0.995). As magnetite nanoparticles coated glass wool showed favorable adsorption behavior for As(V), it can be a promising tool for water purification

Magnetite nanoparticles coated glass wool for As(V) removal from drinking water

Energy Technology Data Exchange (ETDEWEB)

Kango, Sarita; Kumar, Rajesh, E-mail: rajesh.kumar@juit.ac.in [Department of Physics and Materials Science, Jaypee University of Information Technology, Waknaghat, District Solan (H.P.)- 173 234 (India)

2015-08-28

Arsenic (As) removal from contaminated groundwater is a key environmental concern worldwide. In this study, glass wool was coated with magnetite nanoparticles under argon gas flow and magnetite coated glass wool have been investigated for application as an adsorbent for As(V) removal from water. The adsorbent was characterized by using Scanning Electron Microscopy (SEM) and arsenic contaminated water treated with adsorbent was analyzed by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The ICP-MS results showed that 10 g/L of adsorbent removed 99.4% of As(V) within 5 hours at pH-7 and initial arsenic concentration of 360µg/L. Adsorption kinetics data fitted well in pseudo-first-order kinetics model with high correlation coefficient (R{sup 2} = 0.995). As magnetite nanoparticles coated glass wool showed favorable adsorption behavior for As(V), it can be a promising tool for water purification.

Adsorption of ethyl xanthate on ZnS(110) surface in the presence of water molecules: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Long, Xianhao [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Chen, Jianhua, E-mail: jhchen@gxu.edu.cn [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Guangxi Colleges and University Key Laboratory of Minerals Engineering, 530004 (China); Chen, Ye, E-mail: fby18@126.com [College of Resources and Metallurgy, Guangxi University, Nanning 530004 (China)

2016-05-01

Graphical abstract: - Highlights: • Adsorption of water molecules decreases the reactivity of surface Zn atom. • Copper impurities decrease the band gap of ZnS surface. • Copper impurities enhance the adsorption of xanthate on the ZnS surface. • Water molecules have little influence on the properties of Cu-substituted ZnS surface. • The xanthate S atom can interact with the surface S atom of Cu-substituted ZnS surface. - Abstracts: The interaction of collector with the mineral surface plays a very important role in the froth flotation of sphalerite. The adsorptions occurred at the interface between the mineral surface and waters; however most of DFT simulations are performed in vacuum, without consideration of water effect. Semiconductor surface has an obvious proximity effect, which will greatly influence the surface reactivity. To understand the mechanism of xanthate interacting with sphalerite surface in the presence of water molecules, the ethyl xanthate molecule adsorption on un-activated and Cu-activated ZnS(110) surface in the absence and presence of water molecules were performed using the density functional theory (DFT) method. The calculated results show that the adsorption of water molecules dramatically changes the properties of ZnS surface, resulting in decreasing the reactivity of surface Zn atoms with xanthate. Copper activation of ZnS surface changes the surface properties, leading to the totally different adsorption behaviors of xanthate. The presence of waters has little influence on the properties of Cu-activated ZnS surface. The xanthate S atom can interact with the surface S atom of Cu-substituted ZnS surface, which would result in the formation of dixanthogen.

A Review of Removal of Pollutants from Water/Wastewater Using Different Types of Nanomaterials

Directory of Open Access Journals (Sweden)

M. T. Amin

2014-01-01

Full Text Available The rapidly increasing population, depleting water resources, and climate change resulting in prolonged droughts and floods have rendered drinking water a competitive resource in many parts of the world. The development of cost-effective and stable materials and methods for providing the fresh water in adequate amounts is the need of the water industry. Traditional water/wastewater treatment technologies remain ineffective for providing adequate safe water due to increasing demand of water coupled with stringent health guidelines and emerging contaminants. Nanotechnology-based multifunctional and highly efficient processes are providing affordable solutions to water/wastewater treatments that do not rely on large infrastructures or centralized systems. The aim of the present study is to review the possible applications of the nanoparticles/fibers for the removal of pollutants from water/wastewater. The paper will briefly overview the availability and practice of different nanomaterials (particles or fibers for removal of viruses, inorganic solutes, heavy metals, metal ions, complex organic compounds, natural organic matter, nitrate, and other pollutants present in surface water, ground water, and/or industrial water. Finally, recommendations are made based on the current practices of nanotechnology applications in water industry for a stand-alone water purification unit for removing all types of contaminants from wastewater.

Removing efficiency of radon from water by different methods

International Nuclear Information System (INIS)

Muellerova, M.; Holy, K.; Gulasova, Z.; Polaskova, A.

2008-01-01

In this contribution problem of radon removing from water samples by different methods was tested. Lowest efficiency of deemanation was achieved at tossing of water from one vessel into the other. For increasing of efficiency deemanation of radon use of needle-bath principle was also used. Low efficiency deemanation was found at trapping of radon from sample of water by toluene (83 ± 5) %, too. Reversal highest efficiency deemanation of radon from water was reached at aerating by argon (95 ± 6)%. It is shown, that reduction of volume activity of radon in water under 0.1 Bq/dm l - 3 is big problem. Suppression of this limit will claim use of more completion and sophistic approaches. (author)

Research on How to Remove Efficiently the Condensate Water of Sampling System

International Nuclear Information System (INIS)

Cho, SungHwan; Kim, MinSoo; Choi, HoYoung; In, WonHo

2015-01-01

Corrosion was caused in the measurement chamber inside the O 2 and H 2 analyzer, and thus measuring the concentration of O 2 and H 2 was not possible. It was confirmed that the cause of the occurrence of condensate water is due to the temperature difference caused during the process of the internal gas of the disposal and degasifier tank being brought into the analyzer. Thus, a heating system was installed inside and outside of the sampling panel for gas to remove generated condensate water in the analyzer and pipe. For the case where condensate water is not removed by the heating system, drain port is also installed in the sampling panel for gas to collect the condensate water of the sampling system. It was verified that there is a great volume of condensate water existing in the pipe line during the purging process after installing manufactured goods. The condensate water was fully removed by the installed heating cable and drain port. The heating cable was operated constantly at a temperature of 80 to 90 .deg. C, which allows the precise measurement of gas concentration and longer maintenance duration by blocking of the condensate water before being produced. To install instruments for measuring the gas, such as an O 2 and H 2 analyzer etc., consideration regarding whether there condensate water is present due to the temperature difference between the measuring system and analyzer is required

Research on How to Remove Efficiently the Condensate Water of Sampling System

Energy Technology Data Exchange (ETDEWEB)

Cho, SungHwan; Kim, MinSoo; Choi, HoYoung; In, WonHo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

Corrosion was caused in the measurement chamber inside the O{sub 2} and H{sub 2} analyzer, and thus measuring the concentration of O{sub 2} and H{sub 2} was not possible. It was confirmed that the cause of the occurrence of condensate water is due to the temperature difference caused during the process of the internal gas of the disposal and degasifier tank being brought into the analyzer. Thus, a heating system was installed inside and outside of the sampling panel for gas to remove generated condensate water in the analyzer and pipe. For the case where condensate water is not removed by the heating system, drain port is also installed in the sampling panel for gas to collect the condensate water of the sampling system. It was verified that there is a great volume of condensate water existing in the pipe line during the purging process after installing manufactured goods. The condensate water was fully removed by the installed heating cable and drain port. The heating cable was operated constantly at a temperature of 80 to 90 .deg. C, which allows the precise measurement of gas concentration and longer maintenance duration by blocking of the condensate water before being produced. To install instruments for measuring the gas, such as an O{sub 2} and H{sub 2} analyzer etc., consideration regarding whether there condensate water is present due to the temperature difference between the measuring system and analyzer is required.

Removal of emerging micropollutants from water using cyclodextrin.

Science.gov (United States)

Nagy, Zsuzsanna Magdolna; Molnár, Mónika; Fekete-Kertész, Ildikó; Molnár-Perl, Ibolya; Fenyvesi, Éva; Gruiz, Katalin

2014-07-01

Small scale laboratory experiment series were performed to study the suitability of a cyclodextrin-based sorbent (ß-cyclodextrin bead polymer, BCDP) for modelling the removal of micropollutants from drinking water and purified waste water using simulated inflow test solutions containing target analytes (ibuprofen, naproxen, ketoprofen, bisphenol-A, diclofenac, β-estradiol, ethinylestradiol, estriol, cholesterol at 2-6 μg/L level). This work was focused on the preliminary evaluation of BCDP as a sorbent in two different model systems (filtration and fluidization) applied for risk reduction of emerging micropollutants. For comparison different filter systems combined with various sorbents (commercial filter and activated carbon) were applied and evaluated in the filtration experiment series. The spiked test solution (inflow) and the treated outflows were characterized by an integrated methodology including chemical analytical methods gas chromatography-tandem mass spectrometry (GC-MS/MS) and various environmental toxicity tests to determine the efficiency and selectivity of the applied sorbents. Under experimental conditions the cyclodextrin-based filters used for purification of drinking water in most cases were able to absorb more than 90% of the bisphenol-A and of the estrogenic compounds. Both the analytical chemistry and toxicity results showed efficient elimination of these pollutants. Especially the toxicity of the filtrate decreased considerably. Laboratory experiment modelling post-purification of waste water was also performed applying fluidization technology by ß-cyclodextrin bead polymer. The BCDP removed efficiently from the spiked test solution most of the micropollutants, especially the bisphenol-A (94%) and the hormones (87-99%) The results confirmed that the BCDP-containing sorbents provide a good solution to water quality problems and they are able to decrease the load and risk posed by micropollutants to the water systems. Copyright © 2014

Cavity mutants of Savinase. Crystal structures and differential scanning calorimetry experiments give hints of the function of the buried water molecules in subtilisins.

Science.gov (United States)

Pedersen, J T; Olsen, O H; Betzel, C; Eschenburg, S; Branner, S; Hastrup, S

1994-09-23

The subtilisin molecule possesses several internal water molecules, which may be characterised as an integral part of the protein structure. We have introduced specific mutations (T71I, T71S, T71V, T71A and T71G) at position 71 in the subtilisin variant Savinase from Bacillus lentus. This position is involved in a hydrogen bonded network with several internal water molecules, forming a water channel. The water channel and most of the other internal water molecules are positioned in the interface between two half-domains of the subtilisin molecule. The data presented here indicate that the internal water molecules are structural, and may be the result of trapping during the folding process.

Method of removing tritium in exhaust water in a nuclear equipment

Energy Technology Data Exchange (ETDEWEB)

Iwamoto, T

1976-05-12

A method is claimed to increase the efficiency of removing tritium from waste water through adsorption treatment. Steam is produced by heating waste water containing tritium, and it is passed through a tube filled with an adsorbent such as activated alumina, silica gel or zeolite. When a control limiting value is reached by the concentration of tritium within the steam, the flow of steam is stopped, and the adsorption tube is removed from the path of steam flow. Thereafter, another adsorption tube containing the afore-said adsorbent is provided in the steam flow path, and the steam is then allowed to flow again.

Removal of organic compounds from shale gas flowback water

NARCIS (Netherlands)

Butkovskyi, Andrii; Faber, Ann-Hélène; Wang, Yue; Grolle, Katja; Hofman-Caris, Roberta; Bruning, Harry; Van Wezel, Annemarie P.; Rijnaarts, Huub H M

2018-01-01

Ozonation, sorption to granular activated carbon and aerobic degradation were compared as potential treatment methods for removal of dissolved organic carbon (DOC) fractions and selected organic compounds from shale gas flowback water after pre-treatment in dissolved air flotation unit. Flowback

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.

Simultaneous removal of water and BTEX from feed gas for a cryogenic plant

Energy Technology Data Exchange (ETDEWEB)

Jones, S.; Lee, S.; Evans, M.; Chen, R.

1999-07-01

The removal of water and benzene, toluene, ethyl benzene, xylene (BTEX) from the feed gas of a cryogenic plant is critical in order to avoid precipitation of these components in the cold section of the plant. The design of the Hannibal Gas Plant in Sfax, Tunisia, accomplishes the removal of water and BTEX simultaneously. The plant receives 7.1 million Nm{sub 3}/day of feed gas and produces high heating value pipeline quality sales gas by removing nitrogen in the cold box. A methyl diethanol amine (MDEA) treating system at the front end of the plant is designed to remove carbon dioxide. The glycol system takes the saturated gas from the MDEA contactor and reduces the water content to 7 lb/MMscf. The glycol system is also designed to remove more than half of the BTEX from the feed gas so that these aromatic components will not precipitate in the cold section of the plant. GPA experimental data were used to fit the interaction parameters for the computer simulator used to design the glycol system. The results of the plant performance test verify the validity of the design.

Nitrogen and Organics Removal during Riverbank Filtration along a Reclaimed Water Restored River in Beijing, China

Directory of Open Access Journals (Sweden)

Weiyan Pan

2018-04-01

Full Text Available Reclaimed water has been widely used to restore rivers and lakes in water scarce areas as well as in Beijing municipality, China. However, refilling the rivers with reclaimed water may result in groundwater pollution. A three-year field monitoring program was conducted to assess the effect of a riverbank filtration (RBF system on the removal of nitrogen and organics from the Qingyang River of Beijing, which is replenished with reclaimed water. Water samples from the river, sediment, and groundwater were collected for NO3-N, NH4-N, and chemical oxygen demand (COD was measured. The results indicate that about 85% of NO3-N was removed from the riverbed sediments. Approximate 92% of NH4-N was removed during the infiltration of water from river to aquifer. On average, 54% of COD was removed by RBF. The attenuation of NO3-N through RBF to the groundwater varied among seasons and was strongly related to water temperature. On the other hand, no obvious temporal variability was identified in the removal of COD. These results suggest that the RBF system is an effective barrier against NO3-N, NH4-N and COD in the Qingyang River, as well as those rivers with similar geological and climatic conditions refilled with reclaimed water.

Micropollutants removal and health risk reduction in a water reclamation and ecological reuse system.

Science.gov (United States)

Ma, Xiaoyan Y; Li, Qiyuan; Wang, Xiaochang C; Wang, Yongkun; Wang, Donghong; Ngo, Huu Hao

2018-07-01

As reclaimed water use is increasing, its safety attracts growing attention, particularly with respect to the health risks associated with the wide range of micropollutants found in the reclaimed water. In this study, sophisticated analysis was conducted for water samples from a water reclamation and ecological reuse system where domestic wastewater was treated using an anaerobic-anoxic-oxic unit followed by a membrane bioreactor (A 2 O-MBR), and the reclaimed water was used for replenishing a landscape lake. A total of 58 organic micropollutants were detected in the system, consisting of 13 polycyclic aromatic hydrocarbons (PAHs), 16 phenols, 3 pesticides, and 26 pharmaceuticals and personal care products (PPCPs). After treatment by the A 2 O-MBR process, effective removal of pesticides and phenols was achieved, while when the reclaimed water entered the landscape lake, PPCPs were further removed. From the physicochemical properties of micropollutants, it could be inferred that phenols and dichlorphos (the only pesticide with considerable concentration in the influent) would have been mainly removed by biodegradation and/or volatilization in the biological treatment process. Additionally, it is probable that sludge adsorption also contributed to the removal of dichlorphos. For the predominant PPCP removal in the landscape lake, various actions, such as adsorption, biodegradation, photolysis, and ecologically mediated processes (via aquatic plants and animals), would have played significant roles. However, according to their logK oc , logK ow and logD (pH = 8) values, it could be concluded that adsorption by suspended solids might be an important action. Although carcinogenic and non-carcinogenic risks associated with all the detected micropollutants were at negligible levels, the hazard quotients (HQs) of PPCPs accounted for 92.03%-97.23% of the HQ Total . With the significant removal of PPCPs through the ecological processes in the landscape lake, the safety

Removal of endocrine disruptors PAEs in drinking water by gamma-ray irradiation

International Nuclear Information System (INIS)

Zhao Yongfu; Zheng Zheng; Zheng Binguo; Wang Changbao; Li Lili

2012-01-01

Phthalic acid esters (PAEs) belong to environmental endocrine disruptor. The dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-n-butyl phthalate (DBP) were selected for the radiation study. The removal efficiencies of DMP, DEP and DBP in drinking water by gamma-ray irradiation are discussed. The results show that these PAEs could be efficiently removed by gamma-ray irradiation. The removal efficiencies of DMP, DEP and DBP (12 mg/L) in aqueous solutions by 0.8 kGy gamma-ray treatment were 96.6%, 94.5% and 86.2%. The absorbed dose needed for the removal of total carbon in aqueous solutions was much larger than the doses for PAEs degradation. When 2 kGy was selected, the removal efficiencies of TC for DMP, DEP and DBP were only 23.6%, 14.3% and 12.9%. The study results also show that the radiation degradation reaction of PAEs should be divided into two stages: low dose addition reaction and high dose ring-opening reaction. This study is of significance in the disposal of micro-polluted drinking water. (authors)

Centrifuge experiments for removal of aluminium turbidity from Dhruva heavy water

International Nuclear Information System (INIS)

Shetiya, R.S.; Unny, V.K.P.; Nayak, A.P.

1989-01-01

Aluminium turbidity and associated radioactivity was observed in the moderator cum coolant system of Dhruva during initial power operation. Ion exchange resin beds of the purification system were not able to remove aluminium turbidity and radioactivity of system heavy water. Centrifuge technique was used as a convenient alternative method to remove the turbidity and radioactivity. (author)

Using Magnetically Responsive Tea Waste to Remove Lead in Waters under Environmentally Relevant Conditions

KAUST Repository

Yeo, Siang Yee

2013-06-20

We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb2+) ions from water. Magnetite-waste tea composites were dispersed in four different types of water–deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater–that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16–5.55 ppm) of Pb2+ ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb2+ ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ~70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb2+ ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions.

Using Magnetically Responsive Tea Waste to Remove Lead in Waters under Environmentally Relevant Conditions

KAUST Repository

Yeo, Siang Yee; Choi, Siwon; Dien, Vivian; Sow-Peh, Yoke Keow; Qi, Genggeng; Hatton, T. Alan; Doyle, Patrick S.; Thio, Beng Joo Reginald

2013-01-01

We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb2+) ions from water. Magnetite-waste tea composites were dispersed in four different types of water–deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater–that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16–5.55 ppm) of Pb2+ ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb2+ ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ~70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb2+ ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions.

Removal of Water-Soluble Extractives Improves the Enzymatic Digestibility of Steam-Pretreated Softwood Barks.

Science.gov (United States)

Frankó, Balázs; Carlqvist, Karin; Galbe, Mats; Lidén, Gunnar; Wallberg, Ola

2018-02-01

Softwood bark contains a large amounts of extractives-i.e., soluble lipophilic (such as resin acids) and hydrophilic components (phenolic compounds, stilbenes). The effects of the partial removal of water-soluble extractives before acid-catalyzed steam pretreatment on enzymatic digestibility were assessed for two softwood barks-Norway spruce and Scots pine. A simple hot water extraction step removed more than half of the water-soluble extractives from the barks, which improved the enzymatic digestibility of both steam-pretreated materials. This effect was more pronounced for the spruce than the pine bark, as evidenced by the 30 and 11% glucose yield improvement, respectively, in the enzymatic digestibility. Furthermore, analysis of the chemical composition showed that the acid-insoluble lignin content of the pretreated materials decreased when water-soluble extractives were removed prior to steam pretreatment. This can be explained by a decreased formation of water-insoluble "pseudo-lignin" from water-soluble bark phenolics during the acid-catalyzed pretreatment, which otherwise results in distorted lignin analysis and may also contribute to the impaired enzymatic digestibility of the barks. Thus, this study advocates the removal of extractives as the first step in the processing of bark or bark-rich materials in a sugar platform biorefinery.

Combined ion exchange / biological denitrification for nitrate removal from ground water

NARCIS (Netherlands)

Hoek, van der J.P.

1988-01-01

This thesis deals with the development of a new process for nitrate removal from ground water. High nitrate concentrations in ground water are a result of fertilization in agriculture. According to a directive of the European Community the maximum admissible concentration of nitrate in

Banana peel as an adsorbent for removing atrazine and ametryne from waters.

Science.gov (United States)

Silva, Claudineia R; Gomes, Taciana F; Andrade, Graziela C R M; Monteiro, Sergio H; Dias, Ana C R; Zagatto, Elias A G; Tornisielo, Valdemar L

2013-03-13

The feasibility of using banana peel for removal of the pesticides atrazine and ametryne from river and treated waters has been demonstrated, allowing the design of an efficient, fast, and low-cost strategy for remediation of polluted waters. The conditions for removal of these pesticides in a laboratory scale were optimized as sample volume = 50 mL, banana mass = 3.0 g, stirring time = 40 min, and no pH adjustment necessary. KF(sor) values for atrazine and ametryne were evaluated as 35.8 and 54.1 μg g(-1) (μL mL(-1)) by using liquid scintillation spectrometry. Adsorption was also evaluated by LC-ESI-MS/MS. As quantification limits were 0.10 and 0.14 μg L(-1) for both pesticides, sample preconcentration was not needed. Linear analytical curves (up to 10 μg L(-1)), precise results (RSD 90% removal efficiency were attained for both pesticides. Water samples collected near an intensively cultivated area were adequately remedied.

Removal of uranium from water media by bentonite and zeolite

International Nuclear Information System (INIS)

Viglasova, E.; Krajnak, A.; Galambos, M.; Rosskopfova, O.

2014-01-01

The removal and recovery of uranium from contaminated surface, environment and ground water, as result of nuclear industries, has attracted more and more attentions. Several methods are available for removing of uranium, but adsorption among the others, is the most attractive. In case of management of radioactive waste, the adsorption of radionuclides plays significant role. Among the natural sorbents applied to the adsorption of uranium zeolites and bentonites offer a number of advantages. The main aims of this work are investigations of adsorption properties of Greek zeolite Metaxades and Greek bentonite Kimolos during adsorption of uranium from water solutions, comparison of their adsorption characteristics, fitting with isotherms (Freundlich, Langmuir and DR isotherm) and its behaviour during kinetics process influenced by temperature. (authors)

A biomimetic absorbent for removal of trace level persistent organic pollutants from water

International Nuclear Information System (INIS)

Liu Huijuan; Qu Jiuhui; Dai Ruihua; Ru Jia; Wang Zijian

2007-01-01

A novel biomimetic absorbent containing the lipid triolein was developed for removing persistent organic pollutants (POPs) from water. The structural characteristics of the absorbent were obtained by SEM and a photoluminescence method. Under optimum preparation conditions, triolein was perfectly embedded in the cellulose acetate (CA) spheres, the absorbent was stable and no triolein leaked into the water. Dieldrin, endrin, aldrin and heptachlor epoxide were effectively removed by the CA-triolein absorbent in laboratory batch experiments. This suggests that CA-triolein absorbent may serve as a good absorbent for those selected POPs. Triolein in the absorbent significantly increased the absorption capacity, and lower residual concentrations of POPs were achieved when compared to the use of cellulose acetate absorbent. The absorption rate for lipophilic pollutants was very fast and exhibited some relationship with the octanol-water partition coefficient of the analyte. The absorption mechanism is discussed in detail. - Triolein-embedded absorbent was developed and it could remove lipophilic pollutants from water effectively

Overview of technologies for removal of methyl tert-butyl ether (MTBE) from water.

Science.gov (United States)

Levchuk, Irina; Bhatnagar, Amit; Sillanpää, Mika

2014-04-01

Wide use of methyl tert-butyl ether (MTBE) as fuel oxygenates leads to worldwide environment contamination with this compound basically due to fuel leaks from storage or pipelines. Presence of MTBE in drinking water is of high environmental and social concern. Existing methods for MTBE removal from water have a number of limitations which can be possibly overcome in the future with use of emerging technologies. This work aims to provide an updated overview of recent developments in technologies for MTBE removal from water. Copyright © 2014. Published by Elsevier B.V.

Investigation of the Effect of Water Removal from Wells Surrounding Parishan Lake on Groundwater and Surface Water Levels

International Nuclear Information System (INIS)

Shafiei, M.; Raini Sarjaz, M.; Fazloli, R.; Gholami Sefidkouhi, M. A.

2017-01-01

In recent decades the human impacts on global warming and, its consequences, climate change, stirred up earth ecosystems balance and has created many problems all over the world. Unauthorized underground water removal, especially in arid and semi-arid regions of Iran, along with recent decade drought occurrences significantly lowered underground and surface water levels. To investigate the impacts of water removal from surrounding wells in Parishan Lake water level, during 1996 to 2009 interval, 8 buffer layers surrounding the lake were mapped in ArcGIS 9.3 environment. Each buffer layer wells and their total annual discharges were determined. Using SPSS 16 software, the regression equations between wells water levels and water discharges were computed. By employing Thiessen function and creating Thiessen network (TIN) around observation wells, decline of groundwater levels was evaluated. Finally regression equations between wells discharges and groundwater level declines were created. The findings showed that there are highly significant correlations (p ≤ 0.01), in all buffer layers, between water levels and wells discharges. Investigation of the observation wells surrounding lake showed that severe groundwater level declines has been started since the beginning of the first decade of the 21st century. Using satellite images in ArcGIS 9.3 environment it was confirmed that lake’s area has been reduced significantly. In conclusion, it is obvious that human interferences on lake’s natural ecosystem by digging unauthorized wells and removing underground water more than annual recharges significantly impacted surface and groundwater levels.

Pilot scale test of a produced water-treatment system for initial removal of organic compounds

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Enid J [Los Alamos National Laboratory; Kwon, Soondong [UT-AUSTIN; Katz, Lynn [UT-AUSTIN; Kinney, Kerry [UT-AUSTIN

2008-01-01

A pilot-scale test to remove polar and non-polar organics from produced water was performed at a disposal facility in Farmington NM. We used surfactant-modified zeolite (SMZ) adsorbent beds and a membrane bioreactor (MBR) in combination to reduce the organic carbon content of produced water prior to reverse osmosis (RO). Reduction of total influent organic carbon (TOC) to 5 mg/L or less is desirable for efficient RO system operation. Most water disposed at the facility is from coal-bed gas production, with oil production waters intermixed. Up to 20 gal/d of produced water was cycled through two SMZ adsorbent units to remove volatile organic compounds (BTEX, acetone) and semivolatile organic compounds (e.g., napthalene). Output water from the SMZ units was sent to the MBR for removal of the organic acid component of TOC. Removal of inorganic (Mn and Fe oxide) particulates by the SMZ system was observed. The SMZ columns removed up to 40% of the influent TOC (600 mg/L). BTEX concentrations were reduced from the initial input of 70 mg/L to 5 mg/L by the SMZ and to an average of 2 mg/L after the MBR. Removal rates of acetate (input 120-170 mg/L) and TOC (input up to 45 mg/L) were up to 100% and 92%, respectively. The water pH rose from 8.5 to 8.8 following organic acid removal in the MBR; this relatively high pH was likely responsible for observed scaling of the MBR internal membrane. Additional laboratory studies showed the scaling can be reduced by metered addition of acid to reduce the pH. Significantly, organic removal in the MBR was accomplished with a very low biomass concentration of 1 g/L throughout the field trial. An earlier engineering evaluation shows produced water treatment by the SMZ/MBR/RO system would cost from $0.13 to $0.20 per bbl at up to 40 gpm. Current estimated disposal costs for produced water are $1.75 to $4.91 per bbl when transportation costs are included, with even higher rates in some regions. Our results suggest that treatment by an SMZ

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.

Occurrence of illicit drugs in water and wastewater and their removal during wastewater treatment.

Science.gov (United States)

Yadav, Meena K; Short, Michael D; Aryal, Rupak; Gerber, Cobus; van den Akker, Ben; Saint, Christopher P

2017-11-01

This review critically evaluates the types and concentrations of key illicit drugs (cocaine, amphetamines, cannabinoids, opioids and their metabolites) found in wastewater, surface water and drinking water sources worldwide and what is known on the effectiveness of wastewater treatment in removing such compounds. It is also important to amass information on the trends in specific drug use as well as the sources of such compounds that enter the environment and we review current international knowledge on this. There are regional differences in the types and quantities of illicit drug consumption and this is reflected in the quantities detected in water. Generally, the levels of illicit drugs in wastewater effluents are lower than in raw influent, indicating that the majority of compounds can be at least partially removed by conventional treatment processes such as activated sludge or trickling filters. However, the literature also indicates that it is too simplistic to assume non-detection equates to drug removal and/or mitigation of associated risks, as there is evidence that some compounds may avoid detection via inadequate sampling and/or analysis protocols, or through conversion to transformation products. Partitioning of drugs from the water to the solids fraction (sludge/biosolids) may also simply shift the potential risk burden to a different environmental compartment and the review found no information on drug stability and persistence in biosolids. Generally speaking, activated sludge-type processes appear to offer better removal efficacy across a range of substances, but the lack of detail in many studies makes it difficult to comment on the most effective process configurations and operations. There is also a paucity of information on the removal effectiveness of alternative treatment processes. Research is also required on natural removal processes in both water and sediments that may over time facilitate further removal of these compounds in receiving

In field arsenic removal from natural water by zero-valent iron assisted by solar radiation

International Nuclear Information System (INIS)

Cornejo, Lorena; Lienqueo, Hugo; Arenas, Maria; Acarapi, Jorge; Contreras, David; Yanez, Jorge; Mansilla, Hector D.

2008-01-01

An in situ arsenic removal method applicable to highly contaminated water is presented. The method is based in the use of steel wool, lemon juice and solar radiation. The method was evaluated using water from the Camarones River, Atacama Desert in northern Chile, in which the arsenic concentration ranges between 1000 and 1300 μg L -1 . Response surface method analysis was used to optimize the amount of zero-valent iron (steel wool) and the citrate concentration (lemon juice) to be used. The optimal conditions when using solar radiation to remove arsenic from natural water from the Camarones river are: 1.3 g L -1 of steel wool and one drop (ca. 0.04 mL) of lemon juice. Under these conditions, removal percentages are higher than 99.5% and the final arsenic concentration is below 10 μg L -1 . This highly effective arsenic removal method is easy to use and inexpensive to implement. - An in situ arsenic removal method applicable to highly contaminated waters by using zero-valent iron, citrate and solar radiation was developed

In field arsenic removal from natural water by zero-valent iron assisted by solar radiation

Energy Technology Data Exchange (ETDEWEB)

Cornejo, Lorena [Departamento de Quimica, Facultad de Ciencias, Universidad de Tarapaca, Casilla 7-D, Arica (Chile); Laboratorio de Investigaciones Medioambientales de Zonas Aridas, LIMZA, Centro de Investigaciones del Hombre en el Desierto, CIHDE, Arica (Chile)], E-mail: lorenacp@uta.cl; Lienqueo, Hugo; Arenas, Maria [Departamento de Quimica, Facultad de Ciencias, Universidad de Tarapaca, Casilla 7-D, Arica (Chile); Acarapi, Jorge [Departamento de Quimica, Facultad de Ciencias, Universidad de Tarapaca, Casilla 7-D, Arica (Chile); Laboratorio de Investigaciones Medioambientales de Zonas Aridas, LIMZA, Centro de Investigaciones del Hombre en el Desierto, CIHDE, Arica (Chile); Contreras, David; Yanez, Jorge; Mansilla, Hector D. [Facultad de Ciencias Quimicas, Universidad de Concepcion, Casilla 160C, Concepcion (Chile)

2008-12-15

An in situ arsenic removal method applicable to highly contaminated water is presented. The method is based in the use of steel wool, lemon juice and solar radiation. The method was evaluated using water from the Camarones River, Atacama Desert in northern Chile, in which the arsenic concentration ranges between 1000 and 1300 {mu}g L{sup -1}. Response surface method analysis was used to optimize the amount of zero-valent iron (steel wool) and the citrate concentration (lemon juice) to be used. The optimal conditions when using solar radiation to remove arsenic from natural water from the Camarones river are: 1.3 g L{sup -1} of steel wool and one drop (ca. 0.04 mL) of lemon juice. Under these conditions, removal percentages are higher than 99.5% and the final arsenic concentration is below 10 {mu}g L{sup -1}. This highly effective arsenic removal method is easy to use and inexpensive to implement. - An in situ arsenic removal method applicable to highly contaminated waters by using zero-valent iron, citrate and solar radiation was developed.

PVP capped silver nanocubes assisted removal of glyphosate from water-A photoluminescence study.

Science.gov (United States)

Sarkar, Sumit; Das, Ratan

2017-10-05

Glyphosate [N-phosphono-methylglycine (PMG)] is the most used herbicide worldwide and it has been reported very recently that Glyphosate is very harmful and can produce lots of diseases such as alzheimer and parkinson's disease, depression, cancer, infertility including genotoxic effects. As it is mostly present in stable water body and ground water system, its detection and removal is very important. Here, we have shown a fluorescence technique for the removal of glyphosate from water using chemically synthesized polyvinylpyrrolidone (PVP) silver nanocrystals. Transmission Electron Microscopy (TEM) study shows the average size of silver nanocrystals of 100nm approximately with a morphology of cubic shape. Glyphosate does not show absorption in the visible region. But both glyphosate and silver nanocrystals show strong fluorescence in the visible region. So, photoluminescence study has been successfully utilized to detect the glyphosate in water samples and on treating the glyphosate contaminated water sample with silver nanocrystals, the sample shows no emission peak of glyphosate at 458nm. Thus, this approach is a promising and very rapid method for the detection and removal of glyphosate from water samples on treatment with silver nanocubes. NMR spectra further confirms that the silver nanocrystals treated contaminated water samples are glyphosate free. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental Application of an Advanced Separation Process for NOM Removal from Surface Drinking Water Supply

Directory of Open Access Journals (Sweden)

Arianna Callegari

2017-10-01

Full Text Available Natural organic matter (NOM in drinking water supplies significantly impacts on water supply quality and treatment, due to observed reactivity with many dissolved and particulate species. Several technologies are used nowadays to remove NOM from the water supply. The evolution of water-related directives, and progressively more restrictive standards for drinking water, however, call for the investigation of advanced, more efficient, and cost-effective water treatment processes. This paper contains a brief overview on the state-of-the-art methods for NOM removal from supply waters, and describes the experimental application of an advanced technology, tested and validated at the pilot scale on the water supply source of a town in Poland. The process allowed significant removal of natural organic matter (about 50% as Dissolved Organic Carbon and turbidity (from 50% to 90%, however, these results requested significant additions of powdered activated carbon. The key to success of this type of process is a correct setup with the identification of optimal types and dosages of reagents. Based on the results of the tests conducted it is foreseeable that this technology could be used onsite, not only for removal of NOM, but also of other hard-to-tackle pollutants potentially contained in the freshwater supply and not presently considered.

Drugs in Your Drinking Water: Removing Pharmaceutical Pollution

Science.gov (United States)

Richardson, K.

2017-12-01

Pharmaceuticals, mostly estrogen-based hormones and antibiotics, are increasingly polluting waterways and contaminating municipal drinking water sources. A 2008 study funded by the American Water Works Association Research Foundation and the WateReuse Foundation tested 19 drinking water treatment plants across the United States. The study found pharmaceuticals and metabolites at all of the locations tested. These plants provide drinking water for over 28 million Americans - yet only five states test for pharmaceuticals. A 2007 US Government Accountability Office study of male smallmouth bass showed ovarian tissue in their gonads and concluded the combination of EDCs (Endocrine Disrupting Chemicals) likely caused the feminization of the male fish. The purpose of this project is to determine whether bivalves can effectively remove pharmaceuticals as well as other CECs (Contaminants of Emerging Concern).Pharmaceuticals, specifically ibuprofen, were found to be resistant to chemical and mechanical filtration methods, such as coffee grounds and activated carbon, so biological filtration methods are used. Three types of common mollusks (Sphaeriidae `fingernail clams', freshwater mussels, scallops) will be used to assess the potential for biological remediation of the chemical pollutants. Fifteen specimens of each species will be used - a total of 45 individuals. Each group of five will be introduced to either an NSAID (ibuprofen), oil (vegetable) or hormone (estrogen, pending approval). This creates an array of 3 species and 3 contaminants, for a 3x3 grid of nine sample groups. Water is contaminated with pollutant levels similar to EPA measurements. The concentration will be measured before and after the introduction of the specimens using a UV spectrophotometer, at regular time intervals. As mollusks are capable of filtering up to two liters of water a day, the 37.8 liter tanks are filtered at a rate of 10 liters a day. A successful trial of bivalves reducing and

Autotrophic nitrogen removal process in a potable water treatment biofilter that simultaneously removes Mn and NH4(+)-N.

Science.gov (United States)

Cai, Yan'an; Li, Dong; Liang, Yuhai; Zeng, Huiping; Zhang, Jie

2014-11-01

Ammonia (NH4(+)-N) removal pathways were investigated in a potable water treatment biofilter that simultaneously removes manganese (Mn) and NH4(+)-N. The results indicated a significant loss of nitrogen in the biofilter. Both the completely autotrophic nitrogen removal over nitrite (CANON) process and nitrification were more likely to contribute to NH4(+)-N removal. Moreover, the model calculation results demonstrated that the CANON process contributed significantly to the removal of NH4(+)-N. For influent NH4(+)-N levels of 1.030 and 1.749mg/L, the CANON process contribution was about 48.5% and 46.6%, respectively. The most important finding was that anaerobic ammonia oxidation (ANAMMOX) bacteria were detectable in the biofilter. It is interesting that the CANON process was effective even for such low NH4(+)-N concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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.

[Interactions of DNA bases with individual water molecules. Molecular mechanics and quantum mechanics computation results vs. experimental data].

Science.gov (United States)

Gonzalez, E; Lino, J; Deriabina, A; Herrera, J N F; Poltev, V I

2013-01-01

To elucidate details of the DNA-water interactions we performed the calculations and systemaitic search for minima of interaction energy of the systems consisting of one of DNA bases and one or two water molecules. The results of calculations using two force fields of molecular mechanics (MM) and correlated ab initio method MP2/6-31G(d, p) of quantum mechanics (QM) have been compared with one another and with experimental data. The calculations demonstrated a qualitative agreement between geometry characteristics of the most of local energy minima obtained via different methods. The deepest minima revealed by MM and QM methods correspond to water molecule position between two neighbor hydrophilic centers of the base and to the formation by water molecule of hydrogen bonds with them. Nevertheless, the relative depth of some minima and peculiarities of mutual water-base positions in' these minima depend on the method used. The analysis revealed insignificance of some differences in the results of calculations performed via different methods and the importance of other ones for the description of DNA hydration. The calculations via MM methods enable us to reproduce quantitatively all the experimental data on the enthalpies of complex formation of single water molecule with the set of mono-, di-, and trimethylated bases, as well as on water molecule locations near base hydrophilic atoms in the crystals of DNA duplex fragments, while some of these data cannot be rationalized by QM calculations.

Continuum simulations of water flow past fullerene molecules

DEFF Research Database (Denmark)

Popadic, A.; Praprotnik, M.; Koumoutsakos, P.

2015-01-01

We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip boundary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest...... as computed by the present model are in good agreement with results from atomistic and atomistic-continuum simulations at a fraction of the cost. We simulate the flow past a single fullerene and an array of fullerenes and demonstrate that such nanoscale flows can be computed efficiently by continuum flow...

Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment.

Science.gov (United States)

Abebe, Lydia S; Chen, Xinyu; Sobsey, Mark D

2016-02-27

The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI) between 4.7 (± 1.56) and 7.5 (± 0.02) log10 for Escherichia coli, and between 2.8 (± 0.10) and 4.5 (± 1.04) log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

REMOVAL OF ARSENIC IN DRINKING WATER: ARS CFU-50 APC ELECTROFLOCCULATION AND FILTRATION WATER TREATMENT SYSTEM

Science.gov (United States)

ETV testing of the ARS CFU-50 APC Electroflocculation and Filtration Water Treatment System (ARS CFU-50 APC) for arsenic removal was conducted at the Town of Bernalillo Well #3 site from April 18 through May 2, 2006. The source water was chlorinated groundwater from two supply w...

Autotrophic nitrogen removal from low strength waste water at low temperature

NARCIS (Netherlands)

Hendrickx, T.L.G.; Wang, Y.; Kampman, C.; Zeeman, G.; Temmink, B.G.; Buisman, C.J.N.

2012-01-01

Direct anaerobic treatment of municipal waste waters allows for energy recovery in the form of biogas. A further decrease in the energy requirement for waste water treatment can be achieved by removing the ammonium in the anaerobic effluent with an autotrophic process, such as anammox. Until now,

Research on removing reservoir core water sensitivity using the method of ultrasound-chemical agent for enhanced oil recovery.

Science.gov (United States)

Wang, Zhenjun; Huang, Jiehao

2018-04-01

The phenomenon of water sensitivity often occurs in the oil reservoir core during the process of crude oil production, which seriously affects the efficiency of oil extraction. In recent years, near-well ultrasonic processing technology attaches more attention due to its safety and energy efficient. In this paper, the comparison of removing core water sensitivity by ultrasonic wave, chemical injection and ultrasound-chemical combination technique are investigated through experiments. Results show that: lower ultrasonic frequency and higher power can improve the efficiency of core water sensitivity removal; the effects of removing core water sensitivity under ultrasonic treatment get better with increase of core initial permeability; the effect of removing core water sensitivity using ultrasonic treatment won't get better over time. Ultrasonic treatment time should be controlled in a reasonable range; the effect of removing core water sensitivity using chemical agent alone is slightly better than that using ultrasonic treatment, however, chemical injection could be replaced by ultrasonic treatment for removing core water sensitivity from the viewpoint of oil reservoir protection and the sustainable development of oil field; ultrasound-chemical combination technique has the best effect for water sensitivity removal than using ultrasonic treatment or chemical injection alone. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluoride removal from rural spring water using wood ash

CSIR Research Space (South Africa)

Makhado, R

2006-05-01

Full Text Available This paper presents an overview of a report on an investigation on the use of cheap wood ash as an effective means of removing excess fluoride from drinking water used by an impoverished rural community of the Didi village in Limpopo province....

Survival of fish upon removal of cyanide from water

International Nuclear Information System (INIS)

Gacsi, Mariann; Czegeny, Ildiko; Nagy, Gabor; Banfalvi, Gaspar

2005-01-01

The effects of potassium cyanide and the removal of cyanide from water in vivo on the survival of fish were investigated. This research was initiated because of the catastrophe that took place at the end of January 2000 in the Carpathian basin, when an enormous amount of cyanide pollution swept through the Samos and Tisza rivers, and then to the Danube. Since nothing was done against the disaster, we have suggested a chemical solution to remove cyanide from waterways (Chem. Innovat. 30 (2000b) 53). Based on experiments, we describe that the most effective and harmless way to remove cyanide and to save the lives of fish from 40 to 160x the lethal doses of cyanide is to use carbogen gas containing 5% carbon dioxide and 95% oxygen followed by aeration with air

Nano-adsorbents for the removal of metallic pollutants from water and wastewater.

Science.gov (United States)

Sharma, Y C; Srivastava, V; Singh, V K; Kaul, S N; Weng, C H

2009-05-01

Of the variety of adsorbents available for the removal of heavy and toxic metals, activated carbon has been the most popular. A number of minerals, clays and waste materials have been regularly used for the removal of metallic pollutants from water and industrial effluents. Recently there has been emphasis on the application of nanoparticles and nanostructured materials as efficient and viable alternatives to activated carbon. Carbon nanotubes also have been proved effective alternatives for the removal of metallic pollutants from aqueous solutions. Because of their importance from an environmental viewpoint, special emphasis has been given to the removal of the metals Cr, Cd, Hg, Zn, As, and Cu. Separation of the used nanoparticles from aqueous solutions and the health aspects of the separated nanoparticles have also been discussed. A significant number of the latest articles have been critically scanned for the present review to give a vivid picture of these exotic materials for water remediation.

Ordered microporous layered lanthanide 1,3,5-benzenetriphosphonates pillared with cationic organic molecules.

Science.gov (United States)

Araki, Takahiro; Kondo, Atsushi; Maeda, Kazuyuki

2015-04-13

Novel isomorphous pillared-layer-type crystalline lanthanide 1,3,5-benzenetriphosphonates were prepared with bpy and dbo as organic pillars (LnBP-bpy and LnBP-dbo; Ln: Ce, Pr, and Nd). Ab initio crystal structure solution using synchrotron X-ray powder diffraction data revealed that the organic pillars do not exist as neutral coordinating ligands but as cationic molecules. Especially the LnBP-dbo phases have ordered interlayer space filled with water molecules between the dbo pillars, and the interlayer water is successfully removed by heating under vacuum with slightly distorted but basically retained pillared layer structures. Microporosity of the materials is confirmed by adsorption of nitrogen, carbon dioxide, and hydrogen gases. Such microporous layered metal phosphonates pillared with cationic molecules should be unprecedented and should offer new strategies to design ordered microporous materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The spontaneous synchronized dance of pairs of water molecules

Energy Technology Data Exchange (ETDEWEB)

Roncaratti, Luiz F. [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia (Italy); Instituto de Física, Universidade de Brasília, 70910-900 Brasília (Brazil); Cappelletti, David, E-mail: david.cappelletti@unipg.it; Pirani, Fernando [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia (Italy)

2014-03-28

Molecular beam scattering experiments have been performed to study the effect of long-range anisotropic forces on the collision dynamics of two small polar molecules. The main focus of this paper is on water, but also ammonia and hydrogen sulphide molecules have been investigated, and some results will be anticipated. The intermolecular distances mainly probed are of the order of 1 nm and therefore much larger than the molecular dimensions. In particular, we have found that the natural electric field gradient, generated by different spatial orientations of the permanent electric dipoles, is able to promote the transformation of free rotations into coupled pendular states, letting the molecular partners involved in the collision complex swinging to and fro around the field direction. This long-ranged concerted motion manifested itself as large increases of the magnitude of the total integral cross section. The experimental findings and the theoretical treatment developed to shed light on the details of the process suggest that the transformation from free rotations to pendular states depends on the rotational level of both molecules, on the impact parameter, on the relative collision velocity, on the dipole moment product and occurs in the time scale of picoseconds. The consequences of this intriguing phenomenon may be important for the interpretation and, in perspective, for the control of elementary chemical and biological processes, given by polar molecules, ions, and free radicals, occurring in several environments under various conditions.

The spontaneous synchronized dance of pairs of water molecules

International Nuclear Information System (INIS)

Roncaratti, Luiz F.; Cappelletti, David; Pirani, Fernando

2014-01-01

Molecular beam scattering experiments have been performed to study the effect of long-range anisotropic forces on the collision dynamics of two small polar molecules. The main focus of this paper is on water, but also ammonia and hydrogen sulphide molecules have been investigated, and some results will be anticipated. The intermolecular distances mainly probed are of the order of 1 nm and therefore much larger than the molecular dimensions. In particular, we have found that the natural electric field gradient, generated by different spatial orientations of the permanent electric dipoles, is able to promote the transformation of free rotations into coupled pendular states, letting the molecular partners involved in the collision complex swinging to and fro around the field direction. This long-ranged concerted motion manifested itself as large increases of the magnitude of the total integral cross section. The experimental findings and the theoretical treatment developed to shed light on the details of the process suggest that the transformation from free rotations to pendular states depends on the rotational level of both molecules, on the impact parameter, on the relative collision velocity, on the dipole moment product and occurs in the time scale of picoseconds. The consequences of this intriguing phenomenon may be important for the interpretation and, in perspective, for the control of elementary chemical and biological processes, given by polar molecules, ions, and free radicals, occurring in several environments under various conditions

Using Coagulation Process in Optimizing Natural Organic Matter Removal from Low Turbidity Waters

Directory of Open Access Journals (Sweden)

Alireza Mesdaghinia

2006-03-01

Full Text Available Optimization of coagulation process  for efficient removal of Natural Organic Matters (NOM has gained a lot of focus over the last years to meet the requirements of enhanced coagulation. NOM comprises both particulate and soluble components which the latter usually comprises the main portion. Removal of soluble NOM from low turbidity waters by coagulation is not a successful process unless enough attention is paid to stages of formation and development of both micro and macro-flocs. This study, which presents experimental results from pilot scale research studies aimed at optimizing coagulation process applied to synthetic raw waters supplemented by adding commercial humic acid with low turbidity levels, explains how pH and turbidity can be controlled to maximize soluble NOM removal. The removal of NOM at various coagulant doses and coagulation pHs has been assessed through raw and treated (coagulated-settled water measurements of total organic carbon (TOC. For low turbidity waters, essential floc nucleation sites can be provided by creating synthetic turbidities, for example by adding clay. Adjusting the initial pH at 5.5 or adding clay before coagulant addition allows the formation of micro-flocs as well as formation of the insoluble flocs at low coagulant doses.

Biological and Physiochemical Techniques for the Removal of Zinc from Drinking Water: A Review

Directory of Open Access Journals (Sweden)

Naseem Zahra

2015-12-01

Full Text Available Presence of Zinc (II in drinking water beyond permissible limits is considered unsafe for human health. Many different anthropogenic activities including mining, burning of petroleum, industrialization, and urbanization cause a release of considerably higher amounts of zinc into the waterbodies. A permissible limit of 5 mg/L is set by various environmental and pollution control authorities beyond which water may cause respiratory, liver, gonads, and brain disorders. Due to these health hazards, it is important to remove exceeding amounts of zinc from drinking water. Zinc enters drinking water from various sources such as corrosive pipelines, release of industrial effluents, and metal leaching. Different biological and physiochemical techniques are used to remove zinc involving chemical precipitation, ion exchange, adsorption, biosorbents, distillation, ozonation, and membrane filtration technology. Among these technologies, physical process of adsorption using low cost adsorbents is not only economical but abundant, efficient, and easily available. In present review different physiochemical and biological techniques are discussed for the removal of Zinc from drinking water.

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

-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone). However, this removal is a considerable improvement compared to direct discharge into surface 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...

Removal of soluble microbial products as the precursors of disinfection by-products in drinking water supplies.

Science.gov (United States)

Liu, Jin-Lin; Li, Xiao-Yan

2015-01-01

Water pollution worsens the problem of disinfection by-products (DBPs) in drinking water supply. Biodegradation of wastewater organics produces soluble microbial products (SMPs), which can be important DBP precursors. In this laboratory study, a number of enhanced water treatment methods for DBP control, including enhanced coagulation, ozonation, and activated carbon adsorption, were evaluated for their effectiveness in treating SMP-containing water for the DBP reduction purpose. The results show that enhanced coagulation with alum could remove SMPs only marginally and decrease the DBP formation potential (DBPFP) of the water by less than 20%. Although ozone could cause destruction of SMPs in water, the overall DBPFP of the water did not decrease but increased after ozonation. In contrast, adsorption by granular activated carbon could remove the SMP organics from water by more than 60% and reduce the DBPFP by more than 70%. It is apparent that enhanced coagulation and ozonation are not suitable for the removal of SMPs as DBP precursors from polluted water, although enhanced coagulation has been commonly used to reduce the DBP formation caused by natural organic matter. In comparison, activated carbon adsorption is shown as a more effective means to remove the SMP content from water and hence to control the wastewater-derived DBP problem in water supply.

URANIUM REMOVAL FROM DRINKING WATER USING A SMALL FULL-SCALE SYSTEM

Science.gov (United States)

This report presents background and history of water quality, the basis for design and nine months of actual operating data for a small, full-scale strong-base ion exchange system that is used to remove uranium from a water supply serving a school in Jefferson County, CO. Informa...

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. Copyright © 2013 Elsevier B.V. All rights reserved.

Studies on the removal of arsenic (III) from water by a novel hybrid material

International Nuclear Information System (INIS)

Mandal, Sandip; Padhi, T.; Patel, R.K.

2011-01-01

Highlights: → The removal of As (III) is about 98% at pH 7 with the hybrid material (ZrO-EA). → The hybrid material exhibits specific surface area of 201.62 m 2 /g. → The adsorption of arsenic (III) from aqueous solution by the hybrid material is spontaneous. → The material could be easily regenerated with sodium hydroxide at pH 12. - Abstract: The present work provides a method for removal of the arsenic (III) from water. An ion-exchanger hybrid material zirconium (IV) oxide-ethanolamine (ZrO-EA) is synthesized and characterized which is subsequently used for the removal of selective arsenic (III) from water containing 10,50,100 mg/L of arsenic (III) solution. The probable practical application for arsenic removal from water by this material has also been studied. The various parameters affecting the removal process like initial concentration of As (III), adsorbent dose, contact time, temperature, ionic strength, and pH are investigated. From the data of results, it is indicated that, the adsorbent dose of 0.7 mg/L, contact time 50 min after which the adsorption process comes to equilibrium, temperature (25 ± 2), solution pH (5-7), which are the optimum conditions for adsorption. The typical adsorption isotherms are calculated to know the suitability of the process. The column studies showed 98% recovery of arsenic from water especially at low concentration of arsenic in water samples.

Use of biochar amendments for removing bacteria from simulated tile-drainage waters

Science.gov (United States)

The addition of biochar has been shown to increase bacterial removal rates by several orders of magnitude in sand-packed columns, suggesting that biochar may be a suitable amendment for use in end-of-tile filter systems to remove indicator and pathogenic microorganisms in tile-drainage waters. Addit...

Removal of bromide and bromate from drinking water using granular activated carbon.

Science.gov (United States)

Zhang, Yong-Qing; Wu, Qing-Ping; Zhang, Ju-Mei; Yang, Xiu-Hua

2015-03-01

Granular activated carbon (GAC) was used to remove bromide (Br⁻) and bromate (BrO(3)(-)) from drinking water in both bench- and pilot-scale experiments. The present study aims to minimize BrO(3)(-) formation and eliminate BrO(3)(-) generated during the ozonation of drinking water, particularly in packaged drinking water. Results show that the Br⁻ and BrO(3)(-) levels in GAC-treated water decreased in both bench- and pilot-scale experiments. In the bench-scale experiments, when the empty bed contact time (EBCT) was 5 min, the highest reduction rates of Br(-) in the mineral and ultrapure water were found to be 74.9% and 91.2%, respectively, and those of BrO(3)(-) were 94.4% and 98.8%, respectively. The GAC capacity for Br⁻ and BrO(3)(-) removal increased with the increase in EBCT. Reduction efficiency was better in ultrapure water than in mineral water. In the pilot-scale experiments, the minimum reduction rates of Br⁻ and BrO(3)(-) were 38.5% and 73.2%, respectively.

Pilot-scale study of the radiation-induced silica removal from underground brackish water in Saudi Arabia

Energy Technology Data Exchange (ETDEWEB)

Aljohani, Mohammed S. [King Abdulaziz Univ., Jeddah (Saudi Arabia). Nuclear Engineering Dept.

2017-08-01

Silica scaling deposition in industrial water systems is one of the biggest challenges facing the water treatment industry due the low solubility of the scalants in the feed waters. In this preliminary work, we investigated the effectiveness of the ionizing radiation induced removal of silica in water sample from the Salbukh, Saudi Arabia, water treatment plant by using metallic iron as the source of ferric hydroxide to co-precipitate the silica. The influence of several reaction parameters, i.e. iron powder dosage, radiation dose, initial pH and equilibrium pH effect were investigated. In the optimum conditions, up to 75% of silica was removed. This preliminary study showed that this environmentally friendly process is effective in silica removal from underground water.

Arsenic removal from drinking water by a household sand filter in Vietnam--effect of filter usage practices on arsenic removal efficiency and microbiological water quality.

Science.gov (United States)

Nitzsche, Katja Sonja; Lan, Vi Mai; Trang, Pham Thi Kim; Viet, Pham Hung; Berg, Michael; Voegelin, Andreas; Planer-Friedrich, Britta; Zahoransky, Jan; Müller, Stefanie-Katharina; Byrne, James Martin; Schröder, Christian; Behrens, Sebastian; Kappler, Andreas

2015-01-01

Household sand filters are applied to treat arsenic- and iron-containing anoxic groundwater that is used as drinking water in rural areas of North Vietnam. These filters immobilize poisonous arsenic (As) via co-oxidation with Fe(II) and sorption to or co-precipitation with the formed Fe(III) (oxyhydr)oxides. However, information is lacking regarding the effect of the frequency and duration of filter use as well as of filter sand replacement on the residual As concentrations in the filtered water and on the presence of potentially pathogenic bacteria in the filtered and stored water. We therefore scrutinized a household sand filter with respect to As removal efficiency and the presence of fecal indicator bacteria in treated water as a function of filter operation before and after sand replacement. Quantification of As in the filtered water showed that periods of intense daily use followed by periods of non-use and even sand replacement did not significantly (psand replacement, CFUs of Escherichia coli of sand filters regarding As removal, but indicate a potential risk for human health arising from the enrichment of coliform bacteria during filtration and from E. coli cells that are introduced by sand replacement. Copyright © 2014 Elsevier B.V. All rights reserved.

Heavy metal removal from waste waters by ion flotation.

Science.gov (United States)

Polat, H; Erdogan, D

2007-09-05

Flotation studies were carried out to investigate the removal of heavy metals such as copper (II), zinc (II), chromium (III) and silver (I) from waste waters. Various parameters such as pH, collector and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol and methyl isobutyl carbinol (MIBC) were used as frothers. Metal removal reached about 74% under optimum conditions at low pH. At basic pH it became as high as 90%, probably due to the contribution from the flotation of metal precipitates.

Synergistic Removal of Humic Acid in Water by Coupling Adsorption and Photocatalytic Degradation Using TiO2/Coconut Shell Powder Composite

Directory of Open Access Journals (Sweden)

Jong Kyu Kim

2016-01-01

Full Text Available The feasibility of applying nanoscale TiO2/coconut shell powder (TCNSP composite to remove HA in aqueous solution was evaluated, and the optimization of the photocatalytic systems using newly developed TCNSP composite was performed. The developed TCNSP composite has high specific surface area (i.e., 454 m2/g and great porosity (i.e., 66.9% with pore size of less than 5 μm. High removal efficiencies (≥95% of HA were observed due to the significant synergistic effects by coupling adsorption and photocatalytic reaction of TCNSP composite. As the initial concentration of HA increased, the degradation rate (Kapp decreased due to HA sorption saturation to the surface of TCNSP composite and the photon interception by HA molecules in aqueous solution. Since the increased loading amount of TCNSP composite enhanced the number of active sites, Kapp values increased until the optimum loading amount of TCNSP composite. As pH values increased, HA removal efficiency decreased due to increasing electrostatic repulsion between HA and TCNSP composite. Based on the response surface methodology, higher HA removal efficiencies were obtained with acidic condition, longer reaction time, and appropriated loading amount of TCNSP. Further pilot-scale study is in progress using TCNSP composite combined with UVC to remove HA from large amounts of surface water (i.e., 200 m3/d.

Removal of toxic chemicals from water with activated carbon

Science.gov (United States)

Dawson, V.K.; Marking, L.L.; Bills, T.D.

1976-01-01

Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, NoxfishA? (5% rotenone), Dibrorms, juglone, MSa??222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths of 15, 30, and 60 cm; temperatures of 7, 12, 17, and 22 C; pH's of 6.5, 7.5, 8.5, and 9.5; and flow rates of 50, 78, 100, 200, and 940 ml/min. Adsorptive capacity increased when the contact time was increased by reducing the flow rate or increasing the column depth. The adsorptive capacity was not significantly influenced by temperature but was substantially higher at pH 6.5 than at the other pH's tested. A practical and efficient filter for purifying chemically treated water was developed.

Nitrogen Removal from Digested Black Water by One-stage Partial Nitritation and Anammox

DEFF Research Database (Denmark)

Vlaeminck, S.E.; Terada, Akihiko; Smets, Barth F.

2009-01-01

This study assessed the technical feasibility to treat digested black water from vacuum toilets (> 1000 mg NH4+-N L-1) in a lab-scale oxygen-limited autotrophic nitrification/denitrification (OLAND) rotating biological contactor. After an adaptation period of 2.5 months, a stable. nitrogen removal...... conversion was very low, in contrast to the high specific AnAOB activity. DGGE analysis showed that the dominant AerAOB and AnAOB species were resistant to the transition from synthetic medium to digested black water. This study demonstrates high-rate nitrogen removal from digested black water by one...

Biochars made from agro-industrial by-products remove chlorine and lower water toxicity

Science.gov (United States)

Tzachristas, Andreas; Xirou, Maria; Manariotis, Ioannis D.; Dailianis, Stefanos; Karapanagioti, Hrissi K.

2016-04-01

Chlorination is the most common disinfection process for water and treated wastewater. For the industrial use of water in food production, chlorine can add undesired taste and odor to the final product. For this reason, dechlorination is desired for food industries that use municipal tap water. For treated wastewater discharge or reuse, chlorine can be toxic to the receiving aqueous systems and to the irrigated plants. In both the above cases, dechlorination is also required. Traditionally activated carbon has been used as the ideal material for the removal of chlorine. The main mechanisms that describe the interaction between activated carbon and HOCl or OCl- are described by the following equations (AWWA, 1990): HOCl + C* → C*O + H+ + Cl- (1), OCl- + C* → C*O + Cl- (2) Where C* and C*O represent the activated carbon surface and a surface oxide, respectively. The present study proposes the use of agro-industrial by-products for the production of biochars that will be used for dechlorination of tap-water used for food-industry production. Different raw materials such as malt spent rootlets, coffee residue, olive and grape seeds, etc. are used for the production of biochar. Various temperatures and air-to-solid ratios are tested for optimizing biochar production. Batch tests as well as a column test are employed to study the dechlorination efficiency and kinetics of the different raw and biochar materials as well as those of commercial activated carbons. As chlorine concentration increases the removal also increases linearily. After 1 and 24 hours of contact the chlorine relative removal efficiencies for the biochar made from olive seeds are 50 and 77 ± 4%, respectively. It seems that the removal kinetics are faster during the first hour; then, removal continues but with a slower rate. Most of the biochars tested (with 3 mg of solid in 20 mL of chlorine solution at initial concentration Co=1.5 mg/L) demonstrated removal efficiencies with an average of 9.4 ± 0

Pollutants in drinking water - sources, harmful effects and removal procedures

International Nuclear Information System (INIS)

Qadeer, R.

2005-01-01

The underground water resources available for human consumption are being continuously contaminated by the natural sources and anthropogenic activities. The pollutants include toxic microorganism, inorganic and organic chemicals and radionuclide etc. This is an acute problem in our country, where free style way of disposal of industrial effluents into the natural water bodies contaminates the surface and ground water. These contaminants make their way into human body through contaminated drinking water, which leads to the malfunctioning of the body organs. Details of some pollutants present in drinking water, their source and harmful effects on human beings are reviewed in this communication Merits and demerits of methods used to remove the pollutants from drinking water are also discussed. (author)

Carbonate effects on hexavalent uranium removal from water by nanocrystalline titanium dioxide

International Nuclear Information System (INIS)

Wazne, Mahmoud; Meng, Xiaoguang; Korfiatis, George P.; Christodoulatos, Christos

2006-01-01

A novel nanocrystalline titanium dioxide was used to treat depleted uranium (DU)-contaminated water under neutral and alkaline conditions. The novel material had a total surface area of 329 m 2 /g, total surface site density of 11.0 sites/nm 2 , total pore volume of 0.415 cm 3 /g and crystallite size of 6.0 nm. It was used in batch tests to remove U(VI) from synthetic solutions and contaminated water. However, the capacity of the nanocrystalline titanium dioxide to remove U(VI) from water decreased in the presence of inorganic carbonate at pH > 6.0. Adsorption isotherms, Fourier transform infrared (FTIR) spectroscopy, and surface charge measurements were used to investigate the causes of the reduced capacity. The surface charge and the FTIR measurements suggested that the adsorbed U(VI) species was not complexed with carbonate at neutral pH values. The decreased capacity of titanium dioxide to remove U(VI) from water in the presence of carbonate at neutral to alkaline pH values was attributed to the aqueous complexation of U(VI) by inorganic carbonate. The nanocrystalline titanium dioxide had four times the capacity of commercially available titanium dixoide (Degussa P-25) to adsorb U(VI) from water at pH 6 and total inorganic carbonate concentration of 0.01 M. Consequently, the novel material was used to treat DU-contaminated water at a Department of Defense (DOD) site

Nutrient and dissolved organic carbon removal from water using mining and metallurgical by-products.

Science.gov (United States)

Wendling, Laura A; Douglas, Grant B; Coleman, Shandel; Yuan, Zheng

2012-05-15

Excess nutrient input to water bodies frequently results in algal blooms and development of oxygen deficient conditions. Mining or metallurgical by-products can potentially be utilised as filtration media within water treatment systems such as constructed wetlands, permeable reactive barriers, or drain liners. These materials may offer a cost-effective solution for the removal of nutrients and dissolved organic carbon (DOC) from natural waters. This study investigated steel-making, alumina refining (red mud and red sand) and heavy mineral processing by-products, as well as the low-cost mineral-based material calcined magnesia, in laboratory column trials. Influent water and column effluents were analysed for pH and flow rate, alkalinity, nutrient species and DOC, and a range of major cations and anions. In general, by-products with high Ca or Mg, and to a lesser extent those with high Fe content, were well-suited to nutrient and DOC removal from water. Of the individual materials examined, the heavy mineral processing residue neutralised used acid (NUA) exhibited the highest sorption capacity for P, and removed the greatest proportions of all N species and DOC from influent water. In general, NUA and mixtures containing NUA, particularly those with calcined magnesia or red mud/red sand were the most effective in removing nutrients and DOC from influent water. Post-treatment effluents from columns containing NUA and NUA/steel-making by-product, NUA/red sand and NUA/calcined magnesia mixtures exhibited large reductions in DOC, P and N concentrations and exhibited a shift in nutrient ratios away from potential N- and Si-limitation and towards potential P-limitation. If employed as part of a large-scale water treatment scheme, use of these mining and metallurgical by-products for nutrient removal could result in reduced algal biomass and improved water quality. Identification and effective implementation of mining by-products or blends thereof in constructed wetlands

Removal of pollutants from surface water and groundwater by nanofiltration: overview of possible applications in the drinking water industry

International Nuclear Information System (INIS)

Bruggen, Bart van der; Vandecasteele, Carlo

2003-01-01

The nanofiltration system has many potential uses in removing chemical and biological contaminants from water. - During the last decade, nanofiltration (NF) made a breakthrough in drinking water production for the removal of pollutants. The combination of new standards for drinking water quality and the steady improvement of the nanofiltration process have led to new insights, possible applications and new projects on lab-scale, pilot scale and industrial scale. This paper offers an overview of the applications in the drinking water industry that have already been realised or that are suggested on the basis of lab-scale research. Applications can be found in the treatment of surface water as well as groundwater. The possibility of using NF for the removal of hardness, natural organic material (NOM), micropollutants such as pesticides and VOCs, viruses and bacteria, salinity, nitrates, and arsenic will be discussed. Some of these applications have proven to be reliable and can be considered as known techniques; other applications are still studied on laboratory scale. Modelling is difficult due to effects of fouling and interaction between different components. The current insight in the separation mechanisms will be briefly discussed

THE EFFICIENCY OF ELECTROCOAGULATION PROCESS USING ALUMINUM ELECTRODES IN REMOVAL OF HARDNESS FROM WATER

Directory of Open Access Journals (Sweden)

M. Malakootian ، N. Yousefi

2009-04-01

Full Text Available There are various techniques for removal of water hardness each with its own special advantages and disadvantages. Electrochemical or electrocoagulation method due to its simplicity has gained a great attention and is used for removal of various ions and organic matters. The aim of the present study was to investigate the efficiency of this technique in removal of water hardness under different conditions. This experimental study was performed using a pilot plant. The applied pilot was comprised of a reservoir containing aluminum sheet electrodes. The electrodes were connected as monopolar and a power supply was used for supplying direct electrical current. Drinking water of Kerman (southeast of Iran was used in the experiments. The efficiency of the system in three different pH, voltages and time intervals were determined. Results showed the efficiency of 95.6% for electrocoagulation technique in hardness removal. pH and electrical potential had direct effect on hardness removal in a way that the highest efficiency rate was obtained in pH=10.1, potential difference of 20 volt and detention time of 60 minutes. Considering the obtained efficiency in the present study, electrocoagulation technique may be suggested as an effective alternative technique in hardness removal.

Oil adsorbing package, also procedure to remove oil from a water surface

Energy Technology Data Exchange (ETDEWEB)

1971-05-01

A method is given to remove oil from water to prevent water pollution. Use is made of an oil-adsorbing packet having a specific gravity which is lower than the specific gravity of water. The hull is manufactured from any material which is not a water-insoluble nonpolar material. The hull is partly permeable to water and encloses a solid oil-adsorbing compound having a large adsorbing surface. (10 claims)

Examinations on the removal of natural radionuclides from drinking water and overview on their distribution in Austria

International Nuclear Information System (INIS)

Staubmann, K.

2002-09-01

The objective of the thesis was to give an overview about available data regarding natural radioactivity in Austrian ground and spring water and to examine the capability of membrane processes, ion exchange processes and processes for iron and manganese removal to remove natural radionuclides from drinking water. There are already Austrian-wide data existing for the activity concentrations of radon-222 in ground- and spring water, only few values are available for radium-226 (Ra-226), lead-210 (Pb-210), uranium (U) and polonium-210 up til now. From the existing data it is to be expected that in Austria only in exceptions water treatment will be necessary. The tested reverse osmosis and nanofiltration systems removed between 95.6 % and 99.8 % of Ra-226, U and Pb-210 on the average. Laboratory scale experiments for ion exchange showed an essential influence of the concurrent ions in the water on the removal of the radionuclides. With water softeners (cation exchangers) Ra-226 to more than 90 % and Pb to more than 80 % could be removed. By the use of other ones than the standard cartridge fillings for pour-through-filters (ion exchangers) the radionuclides could be removed more selectively and more effectively and the influence on the chemical composition of the water could be minimized. In a laboratory scale experiment simulating the planned treatment process at a waterwork for the removal of iron and manganese Ra-226 was removed to 61%. At the examined processes often disadvantageous side effects onto the water quality which require a subsequent treatment were observed. During the operation of the systems it should be aimed at keeping the activity in the produced waste low so that no radiation protection relevant risk starts from that. (author)

REMOVAL OF BERYLLIUM FROM DRINKING WATER BY CHEMICAL COAGULATION AND LIME SOFTENING

Science.gov (United States)

The effectiveness of conventional drinking water treatment and lime softening was evaluated for beryllium removal from two drinking water sources. ar test studies were conducted to determine how common coagulants (aluminum sulfate and ferric chloride and lime softening performed ...

Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation.

Science.gov (United States)

Jang, Min; Lee, Hyun-Ju; Shim, Yonsik

2010-04-01

The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 microm, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L(-1) FL-2949 (coagulant) and 12 mg L(-1) A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

Micropollutant removal from black water and grey water sludge in a UASB-GAC reactor.

Science.gov (United States)

Butkovskyi, A; Sevenou, L; Meulepas, R J W; Hernandez Leal, L; Zeeman, G; Rijnaarts, H H M

2018-02-01

The effect of granular activated carbon (GAC) addition on the removal of diclofenac, ibuprofen, metoprolol, galaxolide and triclosan in a up-flow anaerobic sludge blanket (UASB) reactor was studied. Prior to the reactor studies, batch experiments indicated that addition of activated carbon to UASB sludge can decrease micropollutant concentrations in both liquid phase and sludge. In continuous experiments, two UASB reactors were operated for 260 days at an HRT of 20 days, using a mixture of source separated black water and sludge from aerobic grey water treatment as influent. GAC (5.7 g per liter of reactor volume) was added to one of the reactors on day 138. No significant difference in COD removal and biogas production between reactors with and without GAC addition was observed. In the presence of GAC, fewer micropollutants were washed out with the effluent and a lower accumulation of micropollutants in sludge and particulate organic matter occurred, which is an advantage in micropollutant emission reduction from wastewater. However, the removal of micropollutants by adding GAC to a UASB reactor would require more activated carbon compared to effluent post-treatment. Additional research is needed to estimate the effect of bioregeneration on the lifetime of activated carbon in a UASB-GAC reactor.

Local area water removal analysis of a proton exchange membrane fuel cell under gas purge conditions.

Science.gov (United States)

Lee, Chi-Yuan; Lee, Yu-Ming; Lee, Shuo-Jen

2012-01-01

In this study, local area water content distribution under various gas purging conditions are experimentally analyzed for the first time. The local high frequency resistance (HFR) is measured using novel micro sensors. The results reveal that the liquid water removal rate in a membrane electrode assembly (MEA) is non-uniform. In the under-the-channel area, the removal of liquid water is governed by both convective and diffusive flux of the through-plane drying. Thus, almost all of the liquid water is removed within 30 s of purging with gas. However, liquid water that is stored in the under-the-rib area is not easy to remove during 1 min of gas purging. Therefore, the re-hydration of the membrane by internal diffusive flux is faster than that in the under-the-channel area. Consequently, local fuel starvation and membrane degradation can degrade the performance of a fuel cell that is started from cold.

Development of improved low-cost ceramic water filters for viral removal in the Haitian context

OpenAIRE

Guerrero Latorre, Laura; Rusiñol Arantegui, Marta; Hundesa Gonfa, Ayalkibet; Garcia Vallès, Maite; Martínez Manent, Salvador; Joseph, Osnick; Bofill Mas, Silvia; Gironès Llop, Rosina

2015-01-01

Household-based water treatment (HWT) is increasingly being promoted to improve water quality and, therefore, health status in low-income countries. Ceramic water filters (CWFs) are used in many regions as sustainable HWT and have been proven to meet World Health Organization (WHO) microbiological performance targets for bacterial removal (24 log); however, the described viral removal efficiencies are insufficient to significantly reduce the associated risk of viral infection. With the object...

Multi-weight isotherm results for mercury removal in upper East Fork Popular Creek water

International Nuclear Information System (INIS)

Bostick, D.A.; Klasson, K.T.

1998-02-01

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, the majority of data published to date do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. The initial mercury content in the majority of the batch samples was significantly augmented so that the equilibrium concentration was similar to that found in the original stream sample for at least one sample. Mercury was successfully removed from actual water via adsorption onto Ionac SR-4 (by Sybron Chemicals, Inc.), Keyle:X (by SolmeteX), and Mersorb (by Nucon International, Inc.) resins to levels below the target goal of 12 ng/L. A thiol-based resin (Ionac SR-4) performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1000 gal of water

Potential of duckweed (Lemna minor) for removal of nitrogen and phosphorus from water under salt stress.

Science.gov (United States)

Liu, Chunguang; Dai, Zheng; Sun, Hongwen

2017-02-01

Duckweed plays a major role in the removal of nitrogen (N) and phosphorus (P) from water. To determine the effect of salt stress on the removal of N and P by duckweed, we cultured Lemna minor, a common species of duckweed, in N and P-rich water with NaCl concentrations ranging from 0 to 100 mM for 24 h and 72 h, respectively. The results show that the removal capacity of duckweed for N and P was reduced by salt stress. Higher salt stress with longer cultivation period exerts more injury to duckweed and greater inhibition of N and P removal. Severe salt stress (100 mM NaCl) induced duckweed to release N and P and even resulted in negative removal efficiencies. The results indicate that L. minor should be used to remove N and P from water with salinities below 75 mM NaCl, or equivalent salt stress. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of high energy radiation in decomposition and removal of organic water pollutants

International Nuclear Information System (INIS)

Toelgyessy, P.

1990-01-01

The present review deals with the radiation chemistry of dilute aqueous solutions of organic substances emphasizing the possibility of use of high energy radiation in waste water treatment. Effects of radiation on biodegradability, toxicity to water organisms and changes in molecules of solutes showing resistance to biochemical degradation and toxicity to water organisms are discussed. (author) 31 refs

Effects of Water Molecule on CO Oxidation by OH: Reaction Pathways, Kinetic Barriers, and Rate Constants.

Science.gov (United States)

Zhang, Linyao; Yang, Li; Zhao, Yijun; Zhang, Jiaxu; Feng, Dongdong; Sun, Shaozeng

2017-07-06

The water dilute oxy-fuel combustion is a clean combustion technology for near-zero emission power; and the presence of water molecule could have both kinetic and dynamic effects on combustion reactions. The reaction OH + CO → CO 2 + H, one of the most important elementary reactions, has been investigated by extensive electronic structure calculations. And the effects of a single water molecule on CO oxidation have been studied by considering the preformed OH(H 2 O) complex reacts with CO. The results show little change in the reaction pathways, but the additional water molecule actually increases the vibrationally adiabatic energy barriers (V a G ). Further thermal rate constant calculations in the temperature range of 200 to 2000 K demonstrate that the total low-pressure limit rate constant for the water assisted OH(H 2 O) + CO → CO 2 + H 2 O + H reaction is 1-2 orders lower than that of the water unassisted one, which is consistent with the change of V a G . Therefore, the hydrated radical OH(H 2 O) would actually slow down the oxidation of CO. Meanwhile, comparisons show that the M06-2X/aug-cc-pVDZ method gives a much better estimation in energy and thus is recommended to be employed for direct dynamics simulations.

Removal of trace organics from water by pervaporation : a technical and economic analysis

NARCIS (Netherlands)

Nijhuis, Herman Henk

1990-01-01

Volatile organic hydrocarbons in ground water, surface water or waste water are a continuous threat to the public health. Often traditional purification techniques cannot be applied to remove these components from aqueous solutions. In this thesis the technical and economic feasibility of

Zinc peroxide nanomaterial as an adsorbent for removal of Congo red dye from waste water.

Science.gov (United States)

Chawla, Sneha; Uppal, Himani; Yadav, Mohit; Bahadur, Nupur; Singh, Nahar

2017-01-01

In the past decade, various natural byproducts, advanced metal oxide composites and photocatalysts have been reported for removal of dyes from water. Although these materials are useful for select applications, they have some limitations such as use at fixed temperature, ultra violet (UV) light and the need for sophisticated experimental set up. These materials can remove dyes up to a certain extent but require long time. To overcome these limitations, a promising adsorbent zinc peroxide (ZnO 2 ) nanomaterial has been developed for the removal of Congo red (CR) dye from contaminated water. ZnO 2 is highly efficient even in the absence of sunlight to remove CR from contaminated water upto the permissible limits set by the World Health Organization (WHO) and the United States- Environmental Protection Agency (US-EPA). The adsorbent has a specific property to adjust the pH of the test solution within 6.5-7.5 range irrespective of acidic or basic nature of water. The adsorption capacity of the material for CR dye was 208mgg -1 within 10min at 2-10pH range. The proposed material could be useful for the industries involved in water purification. The removal of CR has been confirmed by spectroscopic and microscopic techniques. The adsorption data followed a second order kinetics and Freundlich isotherm. Copyright © 2016 Elsevier Inc. All rights reserved.

Molecular Dynamics Study of Water Molecules in Interlayer of 14 ^|^Aring; Tobermorite

KAUST Repository

Yoon, Seyoon

2013-01-01

The molecular structure and dynamics of interlayer water of 14 Å tobermorite are investigated based on molecular dynamics (MD) simulations. Calculated structural parameters of the interlayer water configuration are in good agreement with current knowledge of the refined structure. The MD simulations provide detailed information on the position and mobility of the hydrogen and oxygen of interlayer water, as well as its self-diffusion coefficient, through the interlayer of 14 Å tobermorite. Comparison of the MD simulation results at 100 and 300 K demonstrates that water molecules in the interlayer maintain their structure but change their mobility. The dominant configuration and self-diffusion coefficient of interlayer water are obtained in this study. Copyright © 2013 Japan Concrete Institute.

On the behavior of water at subfreezing temperatures in a protein crystal: evidence of higher mobility than in bulk water.

Science.gov (United States)

Wang, Dongqi; Böckmann, Anja; Dolenc, Jožica; Meier, Beat H; van Gunsteren, Wilfred F

2013-10-03

NMR experiments have shown that water molecules in the crystal of the protein Crh are still mobile at temperatures well below 273 K. In order to investigate this water anomaly, a molecular dynamics (MD) simulation study of crystalline Crh was carried out to determine the mobility of water in this crystal. The simulations were carried out at three temperatures, 150, 200, and 291 K. Simulations of bulk water at these temperatures were also done to obtain the properties of the simple point charge (SPC) water model used at these temperatures and to allow a comparison of the properties of water in the Crh crystal with those of bulk water at the same temperatures. According to the simulations, water is immobilized at 150 K both in crystal and in bulk water. As expected, at 291 K it diffuses and rotates more slowly in the protein crystal than in bulk water. However, at 200 K, the translational and rotational mobility of the water molecules is larger in the crystal than in bulk water. The enhancement of water mobility in the crystal at 200 K was further investigated by MD simulations in which the backbone or all protein atoms were positionally restrained, and in which additionally the electrostatic protein-water interactions were removed. Of these changes in the environment of the water molecules, rigidifying the protein backbones slightly enhanced water diffusion, while it slowed down rotation. In contrast, removal of electrostatic protein-water interactions did not change water diffusion but enhanced rotational motion significantly. Further investigations are required to delineate particular features of the protein crystal that induce the anomalous behavior of water at 200 K.

Metal removal from tailings ponds water using indigenous micro-algae

Energy Technology Data Exchange (ETDEWEB)

Mahdavi, H.; Ulrich, A.; Liu, Y. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

2010-07-01

Each barrel of oil produced by oil sands produce 1.25 m{sup 3} of tailings. The tailings are collected in ponds located at mining sites. The tailing pond water (TPW) must be reclaimed and released into the environment. This PowerPoint presentation discussed a method of removing metals from tailings pond water that used indigenous micro-algae. The in situ experimental method used Parachlorella kessliri to treat 2 ponds. The TPW was enriched with low and high concentrations of nutrients. Dry cell biomass analyses were then conducted, and the pH of the resulting samples was compared. Inductively coupled plasma mass spectrometry analysis methods were used to determine the initial metal concentrations in the raw TPWs. The study showed that the micro-algae remove significantly more metals when high levels of nutrients are used. tabs., figs.

REMOVING AGGRESSIVE CARBON DIOXIDE FROM WATER USING MELAPHYRE BED

Directory of Open Access Journals (Sweden)

Magdalena Maria Michel

2017-09-01

Full Text Available The experiment was based on filtration of the highly aggressive water through the melaphyre bed. The quartz bed was non-reactive reference material. The aim of this work was to determine the ability of the melaphyre to remove aggressive CO2 during the chemical reaction. It was noted that a decrease of acidity of the filtrate in comparison to the feed and an increase of its alkalinity and pH. It was calculated that until the moment of exhaustion of the de-acidifying properties of the melaphyre, maximum amount of bound CO2 added to the water was 29.7 g CO2/L of the bed, and maximum amount of the aggressive CO2 removed from the water was 33.3 g CO2/L of the bed. Regarding very high content of the aggressive CO2 (116 mg/L average in the feed only 28.76% of this component was subject to transformation into bound and affiliated CO2 in the filtrate. For the melaphyre bed the CO2 loss from the experiment system following from desorption was 7.80% of the total load of CO2 added with the feed. On the quartz bed the loss was slightly lower 4.56%.

Removal of arsenic from water using nano adsorbents and challenges: A review.

Science.gov (United States)

Lata, Sneh; Samadder, S R

2016-01-15

Many researchers have used nanoparticles as adsorbents to remove water pollutants including arsenic after modifying the properties of nanoparticles by improving reactivity, biocompatibility, stability, charge density, multi-functionalities, and dispersibility. For arsenic removal, nano adsorbents emerged as the potential alternatives to existing conventional technologies. The present study critically reviewed the past and current available information on the potential of nano adsorbents for arsenic removal from contaminated water and the challenges involved in that. The study discussed the separation and regeneration techniques of nano adsorbents and the performance thereof. The study evaluated the adsorption efficiency of the various nanoparticles based on size of nanoparticles, types of nano adsorbents, method of synthesis, separation and regeneration of the nano adsorbents. The study found that more studies are required on suitable holding materials for the nano adsorbents to improve the permeability and to make the technology applicable at the field condition. The study will help the readers to choose suitable nanomaterials and to take up further research required for arsenic removal using nano adsorbents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Costs of Arsenic Removal Technologies for Small Water Systems: U.S. EPA Arsenic Removal Technology Demonstration Program

Science.gov (United States)

As part of the Arsenic Rule Implementation Research Program, between July 2003 and July 2011, the U.S. environmental Protection Agency (EPA) conducted 50 full-scale demonstration projects on treatment systems removing arsenic from drinking water in 26 states throughout the U.S. ...

Study of the Efficiency of Arsenic Removal from Drinking Water by Granular Ferric Hydroxide (GFH

Directory of Open Access Journals (Sweden)

.R. Asgari

2008-04-01

Full Text Available Background and ObjectivePollution of surface and ground water to arsenic (As has been reported from many parts of the world and in some regions of Iran especially in Kurdistan province. Natural pollution of water to As is in fact dependent to geological characteristics of a region. To day, various methods have been recommended for As removal that each of which has special advantages and drawbacks. Granular ferric hydroxide (GFH is a relatively new adsorbent available in market which is principally introduced for As removal.MethodsThis study was an applied survey in which the effects of changing contact time, As concentration, adsorbent weight, pH as well as the effect of sulfate and chloride ions in arsenic removal were determined. Moreover, the model of absorption by GFH was studied and compared with Freundlich and Langmuir models. Raw data were analyzed by Excel and SPSS softwares. ResultsResults showed that As adsorption by GFH imitate both the Freundlich and Langmuir equations (with R2 >0.95. Optimum PH was 7.5 and duration of the process about 30 minutes was sufficient for optimum removal of As. It was also found that efficiency of As removal was high when small amounts of adsorbent were used. Furthermore, sulfate and chloride ions in concentrations used in this study had no noticeable effect on As removal and Fe added during process remains in the water more than the standard value (0.3 mg/l.ConclusionAccording to this study, GFH could be considered as a suitable adsorbent for As removal from polluted water resources because of its high performance without any needs to PH adjustment. However, there are few drawbacks such as Fe addition and relatively high initial cost. Keywords: Arsenic, Granular Ferric Hydroxide (GFH, Adsorption, Drinking Water

Fluoride removal studies in water using natural materials : technical ...

African Journals Online (AJOL)

Excess fluoride in water causes health hazards to the natural environment. The removal of fluoride was attempted using natural materials such as red soil, charcoal, brick, fly-ash and serpentine. Each material was set up in a column for a known volume and the defluoridation capacities of these materials were studied with ...

Iron coated pottery granules for arsenic removal from drinking water.

Science.gov (United States)

Dong, Liangjie; Zinin, Pavel V; Cowen, James P; Ming, Li Chung

2009-09-15

A new media, iron coated pottery granules (ICPG) has been developed for As removal from drinking water. ICPG is a solid phase media that produces a stable Fe-Si surface complex for arsenic adsorption. Scanning electron microscopy (SEM) was used to document the physical attributes (grain size, pore size and distribution, surface roughness) of the ICPG media. Several advantages of the ICPG media such as (a) its granular structure, (b) its ability to absorb As via the F(0) coating on the granules' surface; (c) the inexpensive preparation process for the media from clay material make ICPG media a highly effective media for removing arsenic at normal pH. A column filtration test demonstrated that within the stability region (flow rate lower than 15L/h, EBCT >3 min), the concentration of As in the influent was always lower than 50 microg/L. The 2-week system ability test showed that the media consistently removed arsenic from test water to below the 5 microg/L level. The average removal efficiencies for total arsenic, As(III), and As(V) for a 2-week test period were 98%, 97%, and 99%, respectively, at an average flow rate of 4.1L/h and normal pH. Measurements of the Freundlich and Langmuir isotherms at normal pH show that the Freundlich constants of the ICPG are very close to those of ferric hydroxide, nanoscale zero-valent iron and much higher than those of nanocrystalline titanium dioxide. The parameter 1/n is smaller than 0.55 indicating a favorable adsorption process [K. Hristovski, A. Baumgardner, P. Westerhoff, Selecting metal oxide nanomaterials for arsenic removal in fixed bed columns: from nanopowders to aggregated nanoparticle media, J. Hazard. Mater. 147 (2007) 265-274]. The maximum adsorption capacity (q(e)) of the ICPG from the Langmuir isotherm is very close to that of nanoscale zero-valent indicating that zero-valent iron is involved in the process of the As removal from the water. The results of the toxicity characteristic leaching procedure (TCLP

Iron coated pottery granules for arsenic removal from drinking water

International Nuclear Information System (INIS)

Dong Liangjie; Zinin, Pavel V.; Cowen, James P.; Ming, Li Chung

2009-01-01

A new media, iron coated pottery granules (ICPG) has been developed for As removal from drinking water. ICPG is a solid phase media that produces a stable Fe-Si surface complex for arsenic adsorption. Scanning electron microscopy (SEM) was used to document the physical attributes (grain size, pore size and distribution, surface roughness) of the ICPG media. Several advantages of the ICPG media such as (a) its granular structure, (b) its ability to absorb As via the F(0) coating on the granules' surface; (c) the inexpensive preparation process for the media from clay material make ICPG media a highly effective media for removing arsenic at normal pH. A column filtration test demonstrated that within the stability region (flow rate lower than 15 L/h, EBCT >3 min), the concentration of As in the influent was always lower than 50 μg/L. The 2-week system ability test showed that the media consistently removed arsenic from test water to below the 5 μg/L level. The average removal efficiencies for total arsenic, As(III), and As(V) for a 2-week test period were 98%, 97%, and 99%, respectively, at an average flow rate of 4.1 L/h and normal pH. Measurements of the Freundlich and Langmuir isotherms at normal pH show that the Freundlich constants of the ICPG are very close to those of ferric hydroxide, nanoscale zero-valent iron and much higher than those of nanocrystalline titanium dioxide. The parameter 1/n is smaller than 0.55 indicating a favorable adsorption process [K. Hristovski, A. Baumgardner, P. Westerhoff, Selecting metal oxide nanomaterials for arsenic removal in fixed bed columns: from nanopowders to aggregated nanoparticle media, J. Hazard. Mater. 147 (2007) 265-274]. The maximum adsorption capacity (q e ) of the ICPG from the Langmuir isotherm is very close to that of nanoscale zero-valent indicating that zero-valent iron is involved in the process of the As removal from the water. The results of the toxicity characteristic leaching procedure (TCLP) analysis

Application of ozonation process for the removal of Legionella pneumophila from water

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Mohammad Safaee

2015-09-01

Full Text Available Background: Legionella pneumophila mortality and morbidity is a health concern worldwide. Due to the role of water in transmission of Legionenlla, several techniques have been used for water disinfection. This research was aimed to analyze the efficacy of ozonation process and the effects of bacterial density, contact time and pH on the removal of Legionella pneumophila from water. Methods: Legionella pneumophila was isolated from hospital water line and spiked into sterile drinking water with 300, 700 and 1000 CFU/ml densities. Ozonation was conducted within 1 L batch glass reactor with injection of 5 mg/h and contact time of 5 to 30 minutes at pH = 5, 7 and 9. Legionella culture was performed in supplemented BCYE containing GVPC and thermal treatment. After ozonation, the developed colonies were identified via biochemical and morphological tests. Results: In pH =5, the contact time 25 min and pH= 7 as well as the contact time 30 min, increase of legionella density from 300 to 1000 CFU/ml led to the reduction of removal efficiency from 100 to 87% and 100 to 82%, respectively. In pH=9 and contact time 20 min with the same bacterial density, 300 to 1000 CFU/ml, the disinfection efficacy was decreased from 100 to 91.5 %. Conclusion: Ozonation is an appropriate technique for elimination of legionella from water. The increased bacterial density led to the reduction of removal efficiency. The lowest and highest performance rates were obtained in pH=7 and 9, respectively.

Removal of fluoride from water using aluminium containing compounds

Institute of Scientific and Technical Information of China (English)

M. Karthikeyan; K. P. Elango

2009-01-01

Batch adsorption studies were undertaken to assess the suitability of aluminium titanate (AT) and bismuth aluminate (BA) to remove fluoride ions from water.The effect of pH,dose of adsorbent,contact time,initial concentration,co-ions and temperature on fluoride removal efficiency were studied.The amounts of fluoride ions adsorbed,at 30℃ from 4 mg/L of fluoride ion solution,by AT and BA are 0.85 and 1.55 mg/g,respectively.The experimental data fitted well to the Freundlich and Langmuir isotherms.Thermodynamic parameters such as △H~0,△S~0 and △G~0 indicated that the removal of fluoride ions by AT is exothermic and non-spontaneous while that by BA is endothermic and spontaneous.Furrier transform infrared (FT-IR) analysis and X-ray diffraction (XRD) patterns of the adsorbent before and after adsorption indicated that fluoride ions are chemisorbed by these adsorbents.

Preparation of fly ash based zeolite for removal of fluoride from drinking water

Science.gov (United States)

Panda, Laxmidhar; Kar, Biswabandita; Dash, Subhakanta

2018-05-01

Fluoride contamination of drinking water is a worldwide phenomenon and scientists are working relentlessly to find ways to remove fluoride from drinking water. Out of the different methods employed for removal fluoride from drinking water adsorption process is the most suitable because in this process the adsorbent is regenerated and the process is cost effective. In the present study fly ash is used as the raw material, which is treated with alkali (NaOH) to form NaP1 zeolite. This zeolite is then subjected to characterization by standard procedures. It is found that the synthesized zeolite has more crystalline character than the raw fly ash and has also more voids and channels on its surface. The surface of the synthesized zeolite is modified with calcium chloride and the same is employed for removal of fluoride under varying pH, contact time, initial concentration of fluoride, temperature and adsorbent dose etc so as to assess the suitably or otherwise of the synthesized product.

Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation

Energy Technology Data Exchange (ETDEWEB)

Jang, M.; Lee, H.J.; Shim, Y. [Korean Mine Reclamation Corporation MIRECO, Seoul (Republic of Korea)

2010-07-01

The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 {mu} m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L{sup -1} FL-2949 (coagulant) and 12 mg L{sup -1} A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

REMOVAL OF ORGANIC MATTER FROM SURFACE WATER USING COAGULANTS WITH VARIOUS BASICITY

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Lidia Dąbrowska

2016-07-01

Full Text Available Humic substances are a natural admixture of surface water and determine the level of organic pollution of water and colour intensity. Application of coagulation process in surface water treatment allows for decrease turbidity and colour of water, as well as organic matter content. In Poland most drinking water treatment plants use aluminium sulphate as a coagulant. Research works on pre-hydrolysed coagulants, e.g. polyaluminium chlorides (general formula Aln(OHmCl3n-m are also carried out. The aim of this study was to evaluate the effectiveness of the coagulation process using polyaluminium chlorides with different basicity, in reducing the level of pollution of surface water with organic substances. Apart from the typical indicators used to evaluate the content of organic compounds, the potential for trihalomethanes formation THM-FP was also determined. The influence of the type of coagulant (low, medium, highly alkaline on the efficiency of organic compound removal, determined as total organic carbon TOC, oxidisability OXI, absorbance UV254, was stated. Under the conditions of the coagulation (pH 7.2-7.4, temperature of 19-21°C, the best results were obtained using highly alkaline polyaluminium chlorides PAX-XL19F, PAX-XL1905 and PAX-XL1910S, decrease in TOC and OXI by 43-46%, slightly worse - 40-41% using low alkaline PAX18. Using the medium alkaline coagulants PAX-XL61 and PAXX-XL69, 30-35% removal of organic matter was obtained. Despite various effects of dissolved organic carbon removal, depending on the used coagulant, THM-FP in purified water did not differ significantly and ranged from 10.0 to 10.9 mgCHCl3 m-3. It was by 37-42% lower than in surface water.

ARSENIC REMOVAL FROM DRINKING WATER BY COAGULATION/FILTRATION AND LIME SOFTENING PLANTS

Science.gov (United States)

This report documents a long term performance (one year) study of 3 water treatment plants to remove arsenic from drinking water sources. The 3 plants consisted of 2 conventional coagulation/filtration plants and 1 lime softening plant. The study involved the collecting of weekly...

The efficiency of macroporous polystyrene ion-exchange resins in natural organic matter removal from surface water

Directory of Open Access Journals (Sweden)

Urbanowska Agnieszka

2017-01-01

Full Text Available Natural water sources used for water treatment contains various organic and inorganic compounds. Surface waters are commonly contaminated with natural organic matter (NOM. NOM removal from water is important e.g. due to lowering the risk of disinfection by-product formation during chlorination. Ion exchange with the use of synthetic ion-exchange resins is an alternative process to typical NOM removal approach (e.g. coagulation, adsorption or oxidation as most NOM compounds have anionic character. Moreover, neutral fraction could be removed from water due to its adsorption on resin surface. In this study, applicability of two macroporous, polystyrene ion exchange resins (BD400FD and A100 in NOM removal from water was assessed including comparison of treatment efficiency in various process set-ups and conditions. Moreover, resin regeneration effectivity was determined. Obtained results shown that examined resins could be applied in NOM removal and it should be noticed that column set-up yielded better results (contrary to batch set-up. Among the examined resins A100 one possessed better properties. It was determined that increase of solution pH resulted in a slight decrease in treatment efficiency while higher temperature improved it. It was also observed that regeneration efficiency was comparable in both tested methods but batch set-up required less reagents.

Biostimulation strategies to enhance manganese removal in drinking water biofilters

DEFF Research Database (Denmark)