Personal Research Database

Full Text: W\Wat Sci Tec40, 231.pdf

Abstract: Humic substances are nor major objectives of water treatment in drinking water supply. But, as they often influence the treatment efficiency or participate in treatment reactions, their behaviour in the treatment process can significantly determine the process design. A very effective pretreatment step can be achieved by soil passage (e. g. bank filtration or slow sand filtration) which is usually involved in German surface water treatment processes. In this study transport phenomena of humic matter during underground passage are investigated with special attention to the alteration of their treatment behaviour. In a fundamental a work the deposition of humic substances was studied in a model system. Transport phenomena could mathematically be described by a filtration theory of colloidal transport. From the results of these calculations the collision efficiencies of humic substances on clean and coated surfaces can be derived. The humic substance deposition on subsurfaces is accompanied by a classification based on molecular weight. An additional alteration of dissolved humic matter due to microbiological degradation and partial resolvation of deposited humic matter was observed by passage of river water through columns containing actual soil. The alteration of dissolved organic matter during soil passage is finally characterized by its adsorption and chlorination precursor behaviour. All results confirm that bank filtration is an effective pretreatment step particulary due to the decrease in connection with improvement in treatability of humic matter. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. An rights reserved.

Keywords: Deposition, Humic Substances, Dissolved Organic Matter, Bank Filtration, Adsorption, THM Precursor

Leung, W.C., Wong, M.F., Chua, H., Lo, W., Yu, P.H.F. and Leung, C.K. (2000), Removal and recovery of heavy metals by bacteria isolated from activated sludge treating industrial effluents and municipal wastewater. Water Science and Technology, 41 (12), 233-240.

Full Text: W\Wat Sci Tec41, 233.pdf

Abstract: A total of nineteen metal-resistant and non-resistant bacteria from activated sludge treating both metal-contaminated industrial effluents and municipal wastewater were isolated and identified. These included both Gram-positive (e.g. Micrococcus) and Gram-negative (e.g. Pseudomonas) bacteria. The biosorption capacity of these strains for five different heavy metals (copper, nickel, zinc, lead and chromium) was determined at pH 5 and initial metal concentration 100 mg/L. Pseudomonas pseudoalcaligenes and Micrococcus luteus were found to be capable of removing significant amounts of copper and lead. Hence, they were selected for further investigations. Langmuir adsorption isotherms adequately represented the distribution of copper and lead for both species. The study of pH effect on metal removal for both species indicated that the metal biosorption increased with increasing pH from 2 to 6. The effect of competing cations on biosorption of P. pseudoalcaligenes was studied. Sulphuric acid (0.05 M) was the most efficient desorption medium among the eleven reagents tested. Over 90% of copper sorbed on the cells of M, luteus could be recovered by washing with 0.05 M sulphuric acid within five minutes. The biosorbent was used for at least five biosorption and desorption cycles without loss of copper removal capacity. Immobilization of M. luteus in 2% calcium alginate and 10% polyacrylamide gel beads increased copper uptake by 61%.

Keywords: Adsorption, Bioremediation, Biosorption, Desorption, Heavy Metals, Wastewater Treatment, Aqueous-Solutions, Accumulation, Biosorption

? Wang, L., Chua, H., Wong, P.K., Lo, W.H., Yu, P.H.F. and Zhao, Y.G. (2000), An optimal magnetite immobilized Pseudomonas-putida 5-x cellsystem for Cu²⁺ removal from industrial waste effluent. Water Science and Technology, 41 (12), 241-246.

Full Text: 2000\Wat Sci Tec41, 241.pdf

Abstract: An optimal magnetite immobilized Pseudomonas putida 5-x cell system was developed to remove Cu²⁺ from industrial waste affluent. Cu²⁺ adsorption capacity of P. putida 5-x cultured in sulphate-limiting medium (SLM) was minimum in early log growth phase, and reached maximum in late stationary growth phase or early death phase. Pretreated cells by 0.6 N HCl could greatly enhance the adsorption capacity of biomass up to 85.6 mg, g and had no significant effect for the loss of P. putida 5-x cells during the pretreatment. In a semi-continuous biosorption system, the removal efficiency of Cu²⁺ from wastewater reached 96%, and recovery efficiency of Cu²⁺ was 95%, and the concentration in the recovery solution was 1.4 g, L using 0.6 N HCl as eluant. The mechanism of Cu²⁺ adsorption by this type of biomass was studied by using the technique of transmission electron microscopy (TEM). Degradation of a peptidoglycan layer on the cell surface was observed after acidic pretreatment, but no further degradation appeared after the adsorption-desorption cycle. TEM and X-ray analysis also showed that Cu²⁺ was mainly accumulated on the cell surface, so it was effectively desorpted by acidic treatment in the desorption process. The process of adsorption obeyed the Freundlich isotherm.

Keywords: Adsorption, Biomass, Biosorption, Copper, Cu(II), Cu²⁺ Adsorption, Growth Phase, Heavy-Metals, Ions, Magnetite-Immobilized Cells, Peptidoglycan Layer, Pseudomonas putida, Ramigera, Sorption And Desorption, Strain, Tem Analysis

Brion, G.M., Mao, H.H. and Lingireddy, S. (2000), New approach to use of total coliform test for watershed management. Water Science and Technology, 42 (1-2), 65-69.

Full Text: W\Wat Sci Tec42, 65.pdf

Abstract: This study monitored surface water quality around a reservoir for a P-year period. It was found that the total coliform test could be used in new ways, and in conjunction with other bacterial and viral indicators. to provide valuable information on the sources of fecal inputs and their potential impact on water quality. Two new approaches to the use of total coliforms were developed. Specifically, it was found that atypical colonies (AC) from the total coliform, membrane filtration test were invaluable input parameters for neural network models that could be trained to recognize and predict potentially hazardous fecal sources from agricultural activities. AC counts were also used in conjunction with total coliphage (TP) concentrations to create a reference index relative to domestic sewage to rank the level of fecal contamination at sites within the watershed. Atypical colonies isolated from total coliform tests of surface water samples were further classified with the API 20E system. The classification showed that the heterogeneous group known as atypicals consisted of three main groups of bacteria: modified coliforms, Aeromonas, and a mix of predominantly Vibrio and Samonella.

Keywords: Coliforms, Atypicals, Coliphage, Watershed Management, Indicators, Neural Networks, Cryptosporidium, Giardia

Lai, C.H., Chen, C.Y., Shih, P.H. and Hsia, T.H. (1999), Competitive adsorption of copper and lead ions on an iron-coated sand from water. Water Science and Technology, 42 (3-4), 149-154.

Full Text: W\Wat Sci Tec42, 149.pdf

Abstract: Iron oxides are good adsorbents for some metal ions. However, the adsorbent properties of these oxides are not fully exploited in water or wastewater operations because of difficulties associated with their separation from the aqueous phase. An oven process with agitators for applying an iron oxide coating onto the sand surface to utilize the adsorbent properties of the coating and filtration properties of the sand media was developed. The competitive adsorption of iron-coated sand for copper and lead ions from water was investigated by batch and column experiments. Among the two metal ions studied, the coated sand has greater affinity for the removal of lead ions compared to copper ions at a concentration of 5×10^-5M, 1×10^-4M and an interval of pH = 2.5 similar to 6.5. Adsorption behaviors of copper and lead ions at the iron oxide/water interface could be proved to form chemisorption through the SEM/EDAX analysis. From the column experiment results, both copper and lead ions could be removed simultaneously by the iron-coated sand in a continuous treatment unit.

Keywords: Adsorption, Coating, Copper, Iron Oxide, Lead, SEM/EDAX, Drinking-Water, Oxide, Filtration, Sorption, Cadmium, Wastes

Ricou-Hoeffer, P., Hequet, V., Lecuyer, I. and Le Cloirec, P. (1999), Adsorption and stabilization of nickel ions on fly ash/lime mixing. Water Science and Technology, 42 (5-6), 79-84.

Full Text: W\Wat Sci Tec42, 79.pdf

Abstract: Experimental design methodology was used to define conditions for the adsorption and the stabilization of nickel ions (initial concentration of 500 mg.L^-1) on coal fly ash/lime sorbent. This type of sorbent allows the reuse of by-products and increases the stabilization of metallic ions by lime addition. It was shown that tho solution pH, the metal/adsorbent mass ratio, the type of fly ash used as sorbent, and the fly ash/lime mass ratio are the most influential factors. A set of parameters was finally obtained (pH 5, metal/adsorbent ratio of 0.01 g.g^-1, fly ash/lime ratio of 4 g.g^-1, fly ash with the lowest content of iron oxide) for which the removal of Ni²⁺ is 96% and the leaching 0.03% by permuted water and 0.2% by acid solution of pH 2.

Keywords: Adsorption, Coal Fly Ash/Lime Sorbent, Experimental Design Methodology, Leaching, Nickel Ions, Ash, Removal

Texier, A.C., Andrès, Y. and Le Cloirec, P. (2000), Selective biosorption of lanthanide (La, Eu, Yb) ions by an immobilized bacterial biomass. Water Science and Technology, 42 (5-6), 91-94.

Full Text: W\Wat Sci Tec42, 91.pdf

Abstract: The removal of metallic ions La³⁺, Eu³⁺ and Yb³⁺ from aqueous solution by immobilized biomass of Pseudomonas aeruginosa was investigated in batch and column reactors. Batch studies consisted in kinetic measurements for lanthanum adsorption by biomass-chitosan beads. Results did not show a significant effect of the presence of bacteria into chitosan matrix on the lanthanum uptake. Then, laboratory scale fixed-bed column experiments were carried out using biomass-entrapped polyacrylamide gel beads, which contained approximately 48% (dry weight basis) of biomass. The lanthanum sorption was dependent on the superficial liquid velocity based on empty column in the range 0.76-2.29 m.h^-1. The removal of lanthan decations (2 mM) at pH 5.0 and 0.76 m, h was 198 mol.g^-1 (dry biomass) for lanthanum, 167 mol.g^-1 for europium and 192 mol.g^-1 for ytterbium (+, -10%). These results are of the order of 1.7-2 times lower than those observed in batch systems with free bacterial cells. Column experiments with mixed-cation solutions showed the following sequence of preferential biosorption: Eu³⁺ > Yb³⁺ > La³⁺.

Keywords: Adsorption, Biosorption, Chitosan, Column, Column Adsorption, Fixed Bed, Fixed Bed Column, Fixed-Bed, Fixed-Bed Column, Immobilized Biomass, Immobilized Cells, Lanthanides, Pseudomonas Aeruginosa, Removal, Selectivity, Sorption, Water

Gelover, S., Leal, T., Bandala, E.R., Roman, A., Jimenez, A. and Estrada, C. (2000), Catalytic photodegradation of alkyl surfactants. Water Science and Technology, 42 (5-6), 101-106.

Full Text: W\Wat Sci Tec42, 101.pdf

Abstract: An attempt to identify intermediate and final products of photocatalytic degradation of sodium dodeylbenzensulfonate (DBSNa) in aqueous solution was carried out. Synthetic samples of DBSNa containing TiO₂ as catalyst were treated in a solar concentrator device. Samples were taken at regular intervals and analyzed by GC/MS. Two main types of signal were observed in the total ion chromatograms. The first group includes signals absent in the untreated sample that appeared during the first phases of the experiment and decreased toward the end. The second group comprised species already present in the untreated sample. There were signals in both groups probably because of stable oxygenated molecules that were accumulated to the ene of treatment, indicating partial mineralization. Results clearly showed that degradation dynamic is complex. The detergent is fragmented into other products that undergo further reactions. The species distribution towards the end of the process is difficult to predict since it depends on a large number of variables including adsorption, reaction rates and the nature of the intermediate products. It is necessary to continue the study to determinate if these molecules are destroyed within the system for longer illumination times.

Keywords: Alkyl Surfactants, Dbsna, Photocatalysis, Photodegradation, Solar Detoxification, TiO₂, Photocatalytic Degradation, Hydrogen-Peroxide, Waste-Water, P-Dioxin, Suspensions, Dyes

Toumi, A., Nejmeddine, A. and El Hamouri, B. (2000), Heavy metal removal in waste stabilisation ponds and high rate ponds. Water Science and Technology, 42 (10-11), 17-21.

Full Text: W\Wat Sci Tec42, 17.pdf

Abstract: Heavy metals, zinc (Zn), copper (Cu) and lead (Pb) removal in two wastewater treatment units were compared. One of the systems consisted of a train of Waste Stabilisation Ponds (WSP) including one anaerobic, three facultative in series and two maturation ponds, also in series. The other system, called High Rate Ponds (HRP) consisted of one anaerobic, one High Rate Algal Pond (HRAP) and two maturation ponds in series. The two treatment systems were located on the same site and received the same wastewater. Data collected from the two treatment systems, for a period of three consecutive months (May, June and July, 1995) show that the content of the three elements in the crude wastewater of the city of Ouarzazate varied from 210 to 340 mg/l for Zn; 35 to 55 for Cu and 30 to 25 for Pb. The removal rate for the three elements reached 91, 92 and 71% respectively for Zn, Gu and Pb in the WSP train. The corresponding values in the HRP train were, respectively 89, 88 and 51%. However, since the two trains were not receiving the same Row, the use of specific removal rate expressed as mg removed m^-1 d^-1 showed that the HRAP was 1.3, 10 and 2 times more efficient respectively for Zn, Cu and Ph removal than the three facultative ponds in series of the WSP. Also, the collected data showed that the content of the sediment of the anaerobic pond was high for all the three elements. However, the recorded concentrations 613, 99 and 78 mg/kg, respectively for Zn, Cu and Pb did not exceed the EEG recommended limits.

Keywords: Wastewater Treatment, Waste Stabilisation Ponds, High Rate Ponds, High Rate Algal Pond, Heavy Metals, Rate Algal Pond

Jodra, Y. and Mijangos, F. (2001), Ion exchange selectivities of calcium alginate gels for heavy metals. Water Science and Technology, 43 (2), 237-244.

Full Text: W\Wat Sci Tec43, 237.pdf

Abstract: An equilibrium model has been proposed and verified, based on the conditions in the gel phase and Donnan equilibrium theory, for the analysis of the experimental data on the recovery of lead, copper, cadmium, cobalt, nickel and zinc from synthetic, nonmetallic aqueous solutions on calcium alginate gels. This equilibrium model considers that the system behaves as an ion-exchange process between the calcium in the gets and the divalent metals in solution, and that the metallic portion enclosed in gel fluid is supposed an important quantitative contribution to the total amount of metal uptake by gels. According to the equilibrium constants calculated, it is deduced that the selectivity order is: Pb>Cu>Cd>Ni>Zn>Co.

Keywords: Calcium Alginate, Heavy Metals, Ion Exchange Equilibrium, Metal Distribution, New Ion Exchangers, Donnan Model, Equilibrium

Graham, N., Chen, X.G. and Jayaseelan, S. (2001), The potential application of activated carbon from sewage sludge to organic dyes removal. Water Science and Technology, 43 (2), 245-252.

Full Text: W\Wat Sci Tec43, 245.pdf

Abstract: The objective of this research work was to study the potential application of activated carbon from sewage sludge to organic dye removal. Methylene blue and crystal violet were the two dyes investigated in the present study. Three activated carbons were produced from the exclusive sewage sludge (referred to as DS), the sludge with the additive of coconut husk (DC) and sludge with the additive of peanut shell (DP) respectively. They were characterized by their surface area and porosity and their surface chemistry structure. Adsorption studies were performed by the batch technique to obtain kinetic and equilibrium data. The results show that the three sludge derived activated carbons had a developed porosity and marked content of surface functional groups. They exhibited a rapid three-stage adsorption process for both Methylene blue and crystal violet. Their adsorption capacities for the two dyes were high, the carbon DP performed best in the adsorption whereas the carbon DC performed worst. It is therefore concluded that the activated carbons made from sewage sludge and its mixtures are promising for dye removal from aqueous streams.

Keywords: Activated Carbon, Adsorption, Dyes, Coconut Husk, Peanut Shell, Sewage Sludge, Adsorbents, Waste

Wagner, M. and Nicell, J.A. (2001), Peroxidase-catalyzed removal of phenols from a petroleum refinery wastewater. Water Science and Technology, 43 (2), 253-260.

Full Text: W\Wat Sci Tec43, 253.pdf

Abstract: The phenol content of a petroleum refinery wastewater was reduced below the discharge limit following treatment with horseradish peroxidase and H₂O₂. Approximately 58% of GOD, 78% of BOD5, and 95% of toxicity were removed along with the phenols. As a result of treatment, phenols were transformed into less biodegradable compounds which could be removed by subsequent coagulation and precipitation. Optimization of the peroxide concentration led to 20% enzyme savings. The use of PEG and chitosan as protective additives resulted in 4 and 25-fold reductions in enzyme requirements, respectively. Phenol removal did not appear to be adversely affected by the presence of other hydrocarbons that are frequently present in refinery wastewaters.

Keywords: Enzymatic Treatment, Horseradish Peroxidase, Phenol Removal, Petroleum Refinery Wastewater, Toxicity, Pollutants

? Hu, T.L. (2001), Kinetics of azoreductase and assessment of toxicity of metabolic products from azo dyes by Pseudomonas luteola. Water Science and Technology, 43 (2), 261-269.

Full Text: 2001\Wat Sci Tec43, 261.pdf

Abstract: This is a continuous study on a decolorization strain, Pseudomonas luteola, which involves treating seven azo dyes with different structures. This study focuses mainly on determining both the mechanism of decolorization by P, luteola and the activity of azoreductase from P. luteola as well as identifying and assessing the toxicity of metabolic products of azo dyes.

The growth of P. luteola reached the stationary phase after shaking incubation for 24 hours. Then, while being kept static, the color of seven tested azo dyes (100 mg/l) could be removed. The proportion of color removal was between 59-99%, which figure is related to the structure of the dye. Monoazo dyes (RP2B, V2RP and Red 22) showed the fastest rate of decolorization, i.e, from 0.23-0.44 mg dye-mg cell^-1 hr(-1). P. luteola could remove the color of V2RP and a leather dye at a concentration of 200 mg/l, and as to the rest of the azo dyes, it could remove at a concentration of up to 100 mg/l.

Decolorization of RP2B and Red 22 required activation energy of 7.00 J/mol and 6.63 J/mole, respectively, indicating that it was easier for azoreductase to decolorize structurally simple dyes. The kinetics of azoreductase towards seven azo dyes suggested a competitive inhibition model be applied.

Microtox(R) was used to analyze the toxicity of the metabolic products of azo dyes. ECS, showed differences in toxicity before and after the azo dyes had been metabolized. Analysis revealed significant differences between the results obtained by EC50 with Blue 15 and those obtained with the feather dye, indicating that the toxicities of the metabolic products were increased. The differences obtained by EC50 with Red 22, RP2P and V2RP were small, and Black 22 showed no such difference Sulfanic acid and orthanilic acid may be the intermediate products of Violet 9 and RP2B, respectively. However, according to FT-IR analysis, aromatic amines were present in the metabolic product.

Keywords: Azoreductase, Competitive Inhibition, EC50, Microtox (R), Degradation, Decolorization, Biodegradation, Purification, Bacteria

Tiehm, A., Kohnagel, I. and Neis, U. (2001), Removal of chlorinated pollutants by a combination of ultrasound and biodegradation. Water Science and Technology, 43 (2), 297-303.

Full Text: W\Wat Sci Tec43, 297.pdf

Abstract: Chlorinated organic compounds are hazardous pollutants found in waste water, surface water, and ground water. Our study shows that a combination of ultrasonic pretreatment and biodegradation effectively removes the solvent chlorobenzene and the disinfectant 2,4-dicblorophenol, also reduces Adsorbable Organic Halogens (AOX) and Chemical Oxygen Demand (COD). In our experiments, the ultrasonic dechlorination was not influenced by the presence of other soluble organic compounds like acetate or glucose. Dechlorination of chlorobenzene by ultrasound did not lead to toxic or inhibiting reaction products. More than that, the ultrasonic pretreatment significantly reduced the toxicity of 2,4-dichlorophenol and biological activity was initiated after sonication. Residual organic pollutants after ultrasonic pretreatment were eliminated by biodegradation.

Keywords: Aox, Biodegradation, Chlorinated Pollutants, Ultrasonic Dehalogenation, Ultrasound, Aqueous-Solution, 2-Chlorophenol, Destruction, Water

Yang, X.J., Fane, A.G. and MacNaughton, S. (2001), Removal and recovery of heavy metals from wastewaters by supported liquid membranes. Water Science and Technology, 43 (2), 341-348.

Full Text: W\Wat Sci Tec43, 341.pdf

Abstract: The removal and recovery of Cu, Cr and Zn from plating rinse wastewater using supported liquid membranes (SLM) are investigated. SLMs with specific organic extractants as the liquid membrane carriers in series are able to remove and concentrate heavy metals with very high purity, which is very promising for recycling of heavy metals in the electroplating industry. A technical comparison between the membrane process and the conventional chemical precipitation process was made.

Keywords: Heavy Metals, Removal, Wastewaters, Supported Liquid Membranes, Chromium

Jang, A., Kim, S.M., Kim, S.Y., Lee, S.G. and Kim, I.S. (2001), Effect of heavy metals (Cu, Pb, and Ni) on the compositions of EPS in biofilms. Water Science and Technology, 43 (6), 41-48.

Full Text: W\Wat Sci Tec43, 41.pdf

Abstract: A series of batch adsorption tests to estimate the biofilm capacity for removal of the heavy metals (Cu, Pb, and Ni) in wastewater were carried out. The metal sorption results were fitted to the Freundlich isotherm model to compare their sorption capacity. The change of the composition of EPSs (extracellular polymeric substances) was simultaneously represented by the ratio of carbohydrate to protein (C/P) when the biofilm was exposed to the heavy metals. EPS composed of slime loosely bound to the cell and capsular materials was extracted by the four general extraction methods including regular centrifugation, regular centrifugation with formaldehyde, EDTA extraction and steam extraction. Although the various extraction methods showed different results, CIP ratio of biofilm exposed to copper and lead metal ions was generally lower than that of control.

Keywords: Adsorption, Biofilm, Extraction Method, EPS, Extracellular Polymeric Substances, Heavy Metal Activated-Sludge Cultures, Extracellular Polymers, Extraction Methods, Removal

Liu, Y., Lam, M.C. and Fang, H.H.P. (2001), Adsorption of heavy metals by EPS of activated sludge. Water Science and Technology,