Personal Research Database

Full Text: W\Wat Res31, 2969.pdf

Abstract: A two-phase, thermophilic anaerobic reactor was operated with a starch-based feed. Copper, zinc, nickel and lead (3 mM) were individually added to the feed each for a period of 30 h. The results were analysed to determine the extent of metal binding in the acidogenic, first-stage reactor and the degree of protection that this’ afforded to the traditionally more sensitive methanogenic phase. The results showed that zinc and nickel were not bound particularly well, that lead was bound very strongly and that copper had binding characteristics that were between these two extremes. When these findings were compared with an earlier study with a mesophilic sludge, zinc was shown to have a very different behaviour. A possible reason for this is given. An examination of the gas production by the methanogenic stage, in relation to the amount of metal reaching this stage, suggested that the phase separation did not offer any real protection from the toxic effects of heavy metals.

Keywords: Extracellular Polymers, Activated-Sludge, UASB-Reactor, Removal, Thermophilic Sludge, Acidogenic Sludge, Two-Phase Digestion, Heavy Metals, Binding

Afcharian, A., Levi, Y., Kiene, L. and Scribe, P. (1997), Fractionation of dissolved organic matter from surface waters using macroporous resins. Water Research, 31 (12), 2989-2996.

Full Text: W\Wat Res31, 2989.pdf

Abstract: To obtain fractions enriched with biodegradable dissolved organic carbon (BDOC) or with organic compounds responsible for the chlorine demand (CID) and for trihalomethane formation potential (THMFP), Seine river water samples were percolated on various macroporous resins (anionic, cationic and non-ionic) and compared with granulated activated carbon (GAG). In addition, measurement of UV absorbance at 254 nm and the fluorescence index (lambda(excitation) 320 nm) had allowed to follow up the retention of dissolved organic matter by the different adsorbants. In contrast to cationic and non-ionic resins, anionic resins confirm their excellent retention capacity of organic compounds responsible for UV 254 absorbance and fluorescence index. The relative values of BDOC/DOC ratio (mg-C/mg-C) are slightly increased in the effluents of anionic resins, indicating that they retain a little preferentially the refractory fraction instead of the biodegradable fraction. There is no significant difference between the ratio of CID/DOC (mg-Cl-2/mg-C) in influent and effluent of anionic resins. Cationic resin has a low capacity for retention of DOG, but they seem to retain significantly the organic compounds responsible for ClD. The capability of anionic resins to retain THMFP is similar to that of GAG. (C) 1997 Elsevier Science Ltd.

Keywords: Surface Waters, Macroporous Resins, Biodegradable Dissolved Organic Carbon (BDOC), Chlorine Demand, Humic Substances, Granular Activated Carbon (GAC), Fractionation, Adsorption, Aquatic Humic Substances, Thm Precursors, Preparative Isolation, Natural-Waters, Acids, Chlorination, Exchange, Distributions, Filtration, Removal

Lee, H.S. and Volesky, B. (1997), Interaction of light metals and protons with seaweed biosorbent. Water Research, 31 (12), 3082-3088.

Full Text: W\Wat Res31, 3082.pdf

Abstract: Based on their displacement by protons, the following ascending order of light metals affinity toward Sargassum fluitans biomass was observed: Na⁺ ≤≤ K⁺ < Mg²⁺ < Ca²⁺ < Al³⁺. Higher biomass-metal affinities resulted in lowering the leaching tendency of (polysaccharidic) biomass components during the sorption process. More than 12% weight loss of protonated biomass occurred during 2 min of sorption, which should be considered in all stoichiometric and sorption calculations. The rate of proton uptake for Na-loaded and Ca-loaded S. fluitans biomass at pH 4.5 was lower than the rate of desorption at pH 1.1. In the case of Na-loaded S. fluitans, the predominant proton uptake rate was of a zero order. Na uptake by protonated S. fluitans biomass did not take place at all in the presence of Ca and Al ions. However, it increased in the absence of other light metals. Since the affinity of Ca²⁺ for the biomass was much greater than that of Na⁺, the three-component system of Na⁺, H⁺ and Ca²⁺ could be simplified into proton-calcium ion exchange. The initial rate of Ca uptake with protonated S. fluitans biomass at pH 4.5 was lower than that of proton release from biomass. Approximately 20% of Ca²⁺ sorbed was bound to the binding site as a mono-valent ion. Titration and stoichiometric indications pointed to the fact that Al was being sorbed as a hydroxyl complex. (C) 1997 Elsevier Science Ltd. All rights reserved.

Keywords: Biosorption, Protonated Biomass, Light Metals, Protons, Marine Algae, Sargassum Fluitans Biomass

Gomez-Serrano, V., Macias-Garcia, A., Espinosa-Mansilla, A. and Valenzuela-Calahorro, C. (1998), Adsorption of mercury, cadmium and lead from aqueous solution on heat-treated and sulphurized activated carbon. Water Research, 32 (1), 1-4.

Full Text: W\Wat Res32, 1.pdf

Abstract: The adsorption of mercury, cadmium and lead from aqueous solutions on heat-treated and sulphurized activated carbon has been studied comparatively. The adsorption isotherms for the various metals were measured at 298 K, using adsorptive solutions at two pH values. The adsorption was much higher for mercury than for cadmium and lead for all adsorbents. The adsorption of mercury greatly increased for the samples of sulphurized carbon and also, though less, for the sample prepared in N₂. The decrease of pH in the adsorptive solution to pH 2.0 drastically reduced the adsorption of mercury. The effect of pH change on the adsorption of Cd²⁺ and Pb²⁺ occurred with less adsorbents than for mercury. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Activated Carbon, Adsorption, Cadmium, Mercury, Lead

? Karanfil, T., Kilduff, J.E., Schlautman, M.A. and Weber, Jr., W.J. (1998), The oxygen sensitivity of organic macromolecule sorption by activated carbon: Effects of solution chemistry. Water Research, 32 (1), 154-164.

Full Text: 1998\Wat Res32, 154.pdf

Abstract: The influence of solution chemistry (pH, ionic strength and calcium concentration) on the oxygen sensitivity of natural and synthetic dissolved organic macromolecule sorption by granular activated carbon was investigated. Sorption sensitivity to the presence of oxygen was found to decrease with decreasing pH, with increasing ionic strength and with increasing calcium concentration, The influence of oxygen on the extent of sorption by a basic GAC (pH(PZC) = 8.5) appears to be enhanced by increasing phenolic acidity and/or decreasing macromolecule size. The results suggest that open, flexible molecular configurations of organic macromolecules and the direct interactions of these substances with carbon surfaces are important factors with respect to the effects of oxygen on their sorption from aqueous phase. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Acids, Activated Carbon, Adsorption, Adsorption, Dissolved-Oxygen, Gac, Humic Substances, Humics, Matter, Models, Natural Organic Matter, Oxygen, Polymerization, Size-Exclusion, Sorption, Systems, Transport, Water Chemistry

Costa, C. and Márquez, M.C. (1998), Kinetics of the PACT process. Water Research, 32 (1), 107-114.

Full Text: W\Wat Res32, 107.pdf

Abstract: Kinetics of textile dye removal from a dyeing wastewater was researched. Treatment was carried out in an activated sludge lab plant with powdered activated carbon (PACT). A kinetic model that involved dye adsorption on biomass and carbon and dye degradation by microorganisms was developed. The deduced mechanism of dye removal from the mathematical model showed that the PACT process must be considered basically as a biological process, because dye removal is 99% due to microorganisms.

Keywords: Activated Carbon, Powdered Activated Carbon, Kinetics, Dye Removal, Activated Sludge, Wastewater Treatment

Williams, C.J., Aderhold, D. and Edyvean, R.G.J. (1998), Comparison between biosorbents for the removal of metal ions from aqueous solutions. Water Research, 32 (1), 216-224.

Full Text: W\Wat Res32, 216.pdf

Abstract: This study compared the ability of a brown seaweed Ecklonia maxima, a dealginated seaweed waste, alginate fibre and waste Linseed fibre to remove copper. nickel and cadmium from single and mixed metal ion solutions. All experiments were conducted using metal ion solutions of 10 mg/litre in concentration. The study has shown that alginate fibre generally exhibited the best overall metal ion uptake and cadmium ions were the most effectively sequestered by these biosorbents. The study indicates that the uptake of these metal ions is selective once saturation of the biosorbent has been achieved, with copper ions being adsorbed in preference to cadmium and nickel ions.

Keywords: Marine-Algae, Biosorption, Biomass, Copper, Adsorption, Sorption, Alginate, Cadmium, Biosorption, Seaweed Alginate, Wastewater, Copper, Nickel, Cadmium, Waste Biomass, Biomass Capacity

? Sakadevan, K. and Bavor, H.J. (1998), Phosphate adsorption characteristics of soils, slags and zeolite to be used as substrates in constructed wetland systems. Water Research, 32 (2), 393-399.

Full Text: 1998\Wat Res32, 393.pdf

Abstract: Constructed wetlands are used to remove pollutants from wastewater. The performance of such wetlands to remove pollutants from wastewater can be improved by using suitable substrates. In this study the phosphorus (P) adsorption capacities of soils, two industrial by-products and a clinoptilolite material (zeolite) were examined for their potential use as substrates to remove P in constructed wetlands. Both Freundlich and Langmuir adsorption isotherms were used to describe the adsorption characteristics of these substrates. The Langmuir adsorption isotherm was used to calculate the maximum P adsorption capacity of these substrates. One of the industrial by-products, namely blast furnace slag, showed the highest P adsorption capacity (44.2 g P kg^-1 slag) followed by soil samples collected from an operating (Byron Bay) constructed wetland system in Northern NSW (4.2 to 5.2 g P kg^-1 soil). The surface soils collected from two regional constructed wetland systems were found to have the least P adsorption capacity (1153 and 934 mg P kg^-1 soil, respectively for Richmond and Carcoar wetlands). The clinoptilolite material (zeolite), which is used to remove ammonium ion from wastewater, was found to have a P adsorption capacity of 2.15 g kg^-1. The relationship between P adsorption and oxalate extractable iron (Fe) and aluminium (Al) showed that P adsorption related more closely to extractable Al (r² = 0.890) than Fe (r² = 0.736). Multiple regression analysis showed that P adsorption is more closely related to a combination of both oxalate extractable Fe and Al (r² = 0.901) than extractable Fe or Al alone. The P saturation capacity of wetland systems incorporating these substrates is described. The results suggest that selected industrial by-products and adsorptive materials may be used alone or in combination with soils to improve the performance of constructed wetland systems subject to other properties Such as pH, permeability and structural stability of these materials. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Wastewater, Phosphorus, Adsorption, Freundlich, Langmuir, Slags, Zeolite, Phosphorus Removal, Sorption, Clay, pH

Butter, T.J., Evison, L.M., Hancock, I.C., Holland, F.S., Matis, K.A., Philipson, A., Sheikh, A.I. and Zouboulis, A.I. (1998), The removal and recovery of cadmium from dilute aqueous solutions by biosorption and electrolysis at laboratory scale. Water Research, 32 (2), 400-406.

Full Text: W\Wat Res32, 400.pdf

Abstract: A multi-stage process has been developed at laboratory scale for the removal and recovery of cadmium from dilute aqueous solutions. Metal removal is achieved by biosorption of the metal cations onto a free cell suspension of dead Streptomyces biomass in a stirred tank reactor. The solids are then separated from the aqueous phase by flotation or sedimentation. The resulting water, which contains only 10 µg l^-1 residual cadmium, can be safely discharged. The solids are diverted to a filtration unit where they become immobilised as a filter cake. The biomass is then eluted, using an electrolyte solution as the eluant, in order to desorb the bound cadmium ions from the biomass. The eluant is drawn through the biomass filter cake under a soft vacuum resulting in intimate contact between the eluant and the solids. The elution step regenerates the biomass for subsequent biosorption steps and also greatly concentrates the cadmium in the eluate with respect to the original wastewater. Finally, the cadmium is recovered from the eluate by electrolysis using a Rotating Cathode Cell, resulting in cadmium powder and cadmium-depleted electrolyte which is recycled as the eluant. This process is therefore capable of achieving very effective cadmium removal and produces only clean water and solid metal, both commercially useful products. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Cadmium Recovery, Biosorption, Streptomyces, Flotation, Sedimentation, Metal Desorption, Electrolysis, Rotating Cathode Cell, Clean Technology, Water Re-Use

Apak, R., Tütem, E., Hügül, M. and Hizal, J. (1998), Heavy metal cation retention by unconventional sorbents (red muds and fly ashes). Water Research, 32 (2), 430-440.

Full Text: W\Wat Res32, 430.pdf

Abstract: Toxic heavy metals, i.e. copper(II), lead(II) and cadmium(II), can be removed from water by metallurgical solid wastes, i.e. bauxite waste red muds and coal fly ashes acting as sorbents. These heavy-metal-loaded solid wastes mag then be solidified by adding cement to a durable concrete mass assuring their safe disposal. Thus, toxic metals in water have been removed by sorption on to inexpensive solid waste materials as a preliminary operation of ultimate fixation. Metal uptake (sorption) and release (desorption) have been investigated by thermostatic batch experiments. The distribution ratios of metals between the solid sorbent and aqueous solution have been found as a function of sorbent type, equilibrium aqueous concentration of metal and temperature. The breakthrough volumes of the heavy metalsolutions have been measured by dynamic column experiments so as to determine the saturation capacities of the sorbents. The sorption data have been analysed and fitted to linearized adsorption isotherms. These observations are believed to constitute a database for the treatment of one industrial plant’s effluent with the solid waste of another, and also to utilize unconventional sorbents, i.e. metallurgical solid wastes, as cost-effective substitutes in place of the classical hydrous-oxide-type sorbents such as alumina, silica and ferric oxides.

Keywords: Silica-Gel Surface, Aqueous-Solutions, Sorptive Removal, Activated Carbon, Waste-Water, Adsorption, Cadmium, Cesium-137, Behavior, Sr-90, Cadmium(II), Lead(II), Copper(II), Sorption, Red Muds, Fly Ashes

Gharaibeh, S.H., Abu-El-Sha’r, W.Y. and Al-Kofahi, M.M. (1998), Removal of selected heavy metals from aqueous solutions using processed solid residue of olive mill products. Water Research, 32 (2), 498-502.

Full Text: W\Wat Res32, 498.pdf

Abstract: The potential use of processed solid residue of olive mill products (SROOMP) to treat drinking water containing several heavy metals in trace concentrations, namely Cr(III), Ni(II), Pb(II), Cd(II), and Zn(II), was explored. Different experimental approaches including equilibrium batch mode experiments, S.C.anning electron microscopy (SEM), and X-ray fluorescence (XRF) were used to explore the feasibility of this material as an adsorbent far the removal of these heavy metals from aqueous solutions. Results indicate that SROOMP can be used to remove Pb(II) and Zn(II) from aqueous solutions by adsorption (data best fit Fruenlich isotherm) but does not remove the other heavy metals investigated in this study. (C) 1998 Elsevier Science Ltd. All rights reserved.

? Zhang, M., Tay, J.H., Qian, Y. and Gu, X.S. (1998), Coke plant wastewater treatment by fixed biofilm system for COD and NH₃-N removal. Water Research, 32 (2), 519-527.

Full Text: 1998\Wat Res32, 519.pdf

Abstract: Coke plant and coal gasification wastewater have similar characteristics. There are high concentrations of ammonia and organic compounds especially refractory and inhibitory organics in them. Coal is the main energy resource in China hence pollution caused by coke plant and coal gasification wastewater has been severe for decades. The anaerobic-anoxic-oxic (A(1)-A(2)-O) fixed biofilm system was used for coke plant wastewater treatment in this study. The experimental results showed that this system was efficient and stable in NH3-N and COD reductions. The effluent NH3-N and COD were 3.1, 114 mg/l with removal efficiencies of 98.8 and 92.4%, respectively, when the total HRT of the whole system was 31.6 hours. Microorganisms were enumerated and organic transformation in the system was analyzed by GC/MS equipment. Batch tests were also conducted and it was found that anaerobic treatment of coke plant wastewater differed from anoxic treatment. Biodegradable phenolics were removed at lower efficiencies while complicated and high molecular a eight organics were removed at higher efficiencies by anaerobic treatment in comparison with anoxic treatment. The biodegradability of anaerobic effluent was higher than that of anoxic effluent. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Anaerobic, Anoxic, Cod Removal, Coke Plant Wastewater, GC, MS, Microorganic Enumeration, NH₃-N Removal, Organic Compounds, Organics Removal, Oxic, Wastewater, Wastewater Treatment, Water

Lawton, L.A., Cornish, B.J.P.A. and Macdonald, A.W.R. (1998), Removal of cyanobacterial toxins (microcystins) and cyanobacterial cells from drinking water using domestic water filters. Water Research, 32 (3), 633-638.

Full Text: W\Wat Res32, 633.pdf

Abstract: Toxic cyanobacteria are increasingly found in drinking water reservoirs, with cells and/or dissolved toxins entering the potable water supply. The most commonly observed group of cyanobacterial toxins is the microcystins, and concern about their impact on human health has prompted investigations into remedial treatment methods. This study investigates the ability of domestic water filters to remove cyanobacterial cells and microcystins from drinking water. Cyanobacterial cell were removed by the filter, but the percentage removal (c. 60% of filamentous cells compared to only 10% of single cells) appeared to be dependent on the colony morphology. The removal of four microcystins was assessed and their percentage removal varied little, although microcystins-LR appeared to be removed to a slightly lesser extent. Toxin concentration and the presence of cell components did not affect the amount of soluble toxin removed from water. The performance of three different brands of water filter was compared, assessing the reproducibility of cartridges and their efficiency when both new and at the manufacturers recommended half-life. All brands of water filters investigated were found to remove a proportion of the soluble microcystin; however, none removed all the toxin in a single passage through the filter. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Blue-Green-Algae, Protein Phosphatase-1, Activated Carbon, LR, Purification, Adsorption, Microcystins, Cyanobacteria, Blue-Green Algae, Drinking Water

Majone, M., Papini, M.P. and Rolle, E. (1998), Influence of metalspeciation in landfill leachates on kaolinite sorption. Water Research, 32 (3), 882-890.

Full Text: W\Wat Res32, 882.pdf

Abstract: The sorption onto kaolinite of Pb, Cd, Ni and Cu from a landfill leachate was studied in relation to the metalspeciation in the liquid phase. Metal speciation was determined by two different experimental procedures based on the exchangeability on a cation chelating resin (Chelex100) and on the separation by dialysis with membranes at different molecular weight (MW) cut off. The speciation procedures were applied on the leachate before and after equilibration with clay, in order to determine the contribution of the different fractions to the total sorption. As determined by the MW-based procedure, large fractions of dissolved metals were associated to substances with high MW (> 1000 and > 12000 daltons), even if these substances represent only 18% of the total organic content (as determined by chemical oxygen demand, COD). These high-MW fractions contribute to metalsorption onto kaolinite, as also confirmed by the concurrent removal of COD and phenolic substances. As determined by the exchange-based procedure, the main contribution to metalsorption derived from free/labile (rapidly exchangeable) or slowly exchangeable Fractions. However, Pb and Cd were also removed from the stable/inert (not exchangeable) fraction. Because metalsorption is partially due to species that are not exchangeable on Chelex100 and partially to species that have MW more than 1000 daltons, these experimental evidences strongly support that free metals are not the only species participating in the sorption onto kaolinite and that some metalspecies are adsorbed without previous dissociation.

Keywords: Solute Adsorption-Isotherm, Solid-Waste Leachates, Organic-Matter, General Treatment, Cadmium, Identification, Substances, Classification, Separation, Dialysis, Landfill Leachates, Heavy Metals, Speciation, Soil Sorption

Kuan, W.H., Lo, S.L., Wang, M.K. and Lin, C.F. (1998), Removal of Se(IV) and Se(VI) from water by aluminum-oxide-coated sand. Water Research, 32 (3), 915-923.

Full Text: W\Wat Res32, 915.pdf

Abstract: Aluminum-oxide-coated sand (AOCS) was evaluated for the removal of selenite (Se(IV)) and selenate (Se(VI)) from water. Quartz sand was coated at 70°C using 1 M AlCl₃ solution aging for 2 d at various coating pH (pH_(coating)). The characteristics of the AOCS surface were pH-(coating)-dependent. The Al oxide coating was an X-ray noncrystalline, porous compound at low pH_(coating), while at high pH_(coating) the AOCS could better withstand acid/alkali and the coatings tended to form crystalline boehmite and bayerite. Adsorption of Se(IV) and Se(VI) was more effective using sand coated at low pH_(coating) than at high pH_(coating). AOCS produced at pH_(coating) 5.98 had optimum properties and was employed as the adsorbent for the present adsorption studies. Adsorption experiments of Se(IV) and Se(VI) by AOCS performed as a function of pH, initial concentration, reaction time, and competing ion concentrations were examined. Removal of Se(IV) and Se(IV) increased with decreasing pH but was obviously greater for Se(IV) than Se(VI). In Se(IV) and Se(VI) mixed systems, the adsorption of Se(IV) was evidently inhibited by Se(VI) only at system pH ranging from 3 to 8, and the degree of inhibition was similar at Se(VI) to Se(IV) molar ratios of 1 and 3. However, Se(VI) adsorption significantly decreased with increasing Se(IV) concentration at all system pH. The sequence of foreign anions competing with respect to Se(IV) and Se(VI) adsorption was in the order of SO₄^2-> HCO₃^-. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Iron-Oxide, Selenite Adsorption, Sulfate Adsorption, Surface-Charge, Mixed Oxides, Interface, Goethite, Complexation, Sorption, Selenate, Aluminum-Oxide-Coated Sand, Se(IV), Se(VI), Coating, Adsorption

Namasivayam, C. and Ranganathan, K. (1998), Effect of organic ligands on the removal of Pb(II), Ni(II) and Cd(II) by ‘waste’ Fe(III)/Cr(III) hydroxide. Water Research,