Personal Research Database

Tsezos, M. and Seto, W. (1986), The adsorption of chloroethanes by microbial biomass. Water Research, 20 (7), 851-858.

Full Text: W\Wat Res20, 851.pdf

Abstract: The adsorption isotherms of halogenated aliphatic hydrocarbons by various selected types of inactive microbial biomass were determined. The isotherms were shown to be independent of the initial organic solution concentration and could be described by a modified Freundlich adsorption equation. Biosorptive uptake capacities varied among the biomass species. The water solubility and the octanol/water partition coefficient of the tested organics affected the biomass uptake capacity. In general, the least water soluble component showed the greatest tendency to be accumulated by the microbial biomass. The results also suggest that structural differences among the various microbial biomass types and possibly the fragmentation of the microbial cells, also affect the biomass uptake capacity for both single and mixed-solute systems.

Keywords: Adsorption, Biosorption, Toxic Organics, Biomass, Microorganisms, Chloroethanes

Brattebø, H. and Ødegaard, H. (1986), Phosphorus removal by granular activated alumina. Water Research, 20 (8), 977-986.

Full Text: W\Wat Res20, 977.pdf

Abstract: Phosphorus removal from wastewater may be carried out by fixed-bed adsorption using activated alumina. In order to prevent unacceptable head-losses coarse-grained alumina must be used. Such systems have been referred to by several authors in literature. The mass transport characteristics of the system has so far, however, not been given a thorough investigation. This study uses the homogeneous surface diffusion model (HSDM) to describe the process as influenced by the system parameters.

A sensitivity analysis is presented to optimize the process design for given conditions. The pH, the alumina particle size and the column length are found to be very important parameters determining the column performance. The process is very well suited for designing a beds-in-series system.

Keywords: Wastewater, Phosphorus, Removal, Adsorption, Activated Alumina, Modelling

Martin, T.R. and Holdich, D.M. (1986), The acute lethal toxicity of heavy-metals to peracarid crustaceans (with particular reference to fresh-water asellids and gammarids). Water Research, 20 (9), 1137-1147.

Full Text: W\Wat Res20, 1137.pdf

Abstract: In static tests on the acute toxicity of metal salts to two fresh-water peracarids, Asellus aquaticus (L.) (Isopoda) and Crangonyx pseudogracilis Bousfield (Amphipoda), 48 and 96 h LC₅₀ values were determined for Al(III), Cd(II), Cr(III), Cu(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II) and Zn(II). Additional metals tested upon Crangonyx alone were Ag(I), Co(II), Cr(VI), Fe(II), Mn(VII), Mo(VI), Sn(II) and V(V). Of the metal salts tested on both species, Asellus was more sensitive to Al(III) and Mn(II) than Crangonyx, similarly sensitive to Cd(II), Fe(III) and Zn(II), and less sensitive to the remainder. Toxicity of metal salts which are unstable with respect to reduction or oxidation was found to be higher than that of the corresponding stable salts of the same metal.

Previously published data on the acute toxicity of heavy metal salts to fresh-water, estuarine and marine amphipods and isopods are tabulated and discussed. Brief comparisons are also made between the relative tolerances of peracarids, Daphnia and fresh-water fish. Crangonyx pseudogracilis is recommended as worthy of further research, due to its widespread distribution and ease of culture.

Keywords: Heavy Metals, Acute Toxicity, LC₅₀, Crustaceans, Peracarids, Asellus, Crangonyx

Grau, P., Sutton, P.M., Henze, M., Elmaleh, S., Grady, C.P., Gujer, W. and Koller, J. (1987), Notation for use in the description of wastewater treatment processes. Water Research, 21 (2), 135-139.

Full Text: W\Wat Res21, 135.pdf

McKay, G., Ramprasad, G. and Pratapa Mowli, P. (1987), Desorption and regeneration of dye colors from low-cost materials. Water Research, 21 (3), 375-377.

Full Text: W\Wat Res21, 375.pdf

Abstract: Experimental methods and results are reported in this paper on the desorption and regeneration of eight dye colours individually from six low-cost sorbent materials. Desorption and regeneration values give an idea about the type of interaction between the sorbate and the sorbent, and the possibility of regeneration of the sorbent. Bentonite clay, amongst the six low-cost materials studied in the present investigation, could sorb all the dyes used in investigation with the exception of the acid dyes. No regeneration of clay is possible in the sorption of dyes, since strong chemical bonding occurs between it and the sorbed dyes. Rice husk, bark, cotton waste and hair could sorb only the red and blue basic dyes and a combination of ion-exchange and chemical bonding occurs in the sorption process.

Keywords: Dyes, Sorption/Desorption, Sorbents

? Henze, M., Grady, Jr., C.P.L., Gujer, W., Marais, G.V.R. and Matsuo, T. (1987), A general model for single-sludge wastewater treatment systems. Water Research, 21 (5), 505-515.

Full Text: 1987\Wat Res21, 505.pdf

Abstract: In 1983 IAWPRC formed a task group to facilitate the application of practical models to the design and operation of biological wastewater treatment systems. This paper is a summary of the report prepared by the task group. It presents the model development for single-sludge systems performing carbon oxidation, nitrification and denitrification. The model includes eight fundamental processes: aerobic growth of heterotrophic biomass, anoxic growth of heterotrophic biomass, aerobic growth of autotrophic biomass, decay of heterotrophic biomass, decay of autotrophic biomass, ammonification of soluble organic nitrogen, hydrolysis of entrapped particulate organic matter, and hydrolysis of entrapped organic nitrogen. Methods are suggested for characterization of wastewaters and estimation of parameter values in ways consistent with the model. Finally, techniques are presented by which the model may be implemented for both education and engineering practice.

? Elrehaili, A.M. and Weber, Jr., W.J. (1987), Correlation of humic substance trihalomethane formation potential and adsorption behavior to molecular-weight distribution in raw and chemically treated waters. Water Research, 21 (5), 573-582.

Full Text: 1987\Wat Res21, 573.pdf

Abstract: The molecular weight distributions (MWDs) of several commercially prepared humic and fulvic acids and organic matter present in natural waters were analyzed by gel chromatography. The responses of these substances to treatment by alum coagulation, lime softening, and activated carbon adsorption were also analyzed, as were their trihalomethane formation potentials before and after each treatment. The treatability characteristics and trihalomethane formation properties of the different organic substances were then related to their respective MWDs. Differences in the MWDs were found to effect differences in the behavior of lumped parameter measures of organic matter (such as TOC) with respect to the several treatment operations. The treatments in turn were observed to alter the MWDs of the organic substances as well as their phenomenological behavior in subsequent process operations.

Keywords: Humic Substances, Molecular Weight Distributions, Water Treatment, Adsorption, Coagulation, Softening, Trihalomethane Formation Potential

? Sen, A.K. and De, A.K. (1987), Adsorption of mercury(II) by coal fly ash. Water Research, 21 (8), 885-888.

Full Text: 1987\Wat Res21, 885.pdf

Abstract: Coal fly ash, an industrial solid waste, was found to have a good adsorption capacity for mercury(II). Adsorption of mercury(II) on coal fly ash conforms to Freundlich’s adsorption model. Several parameters such as time of equilibration, effect of pH, effect of initial concentration of solute, effect of fly ash dose etc. were studied. The maximum adsorption was observed after shaking for 3 h. Solution pH was the most important parameter affecting the adsorption. The optimum pH range was 3.5–4.5. There was total adsorption of mercury below 10 mg l⁻¹. The performance of coal fly ash as an adsorbent was found to be significant when compared with activated powdered charcoal.

Keywords: Coal Fly Ash, Adsorption, Mercury, Flameless Atomic Absorption

Corapcioglu, M.O. and Huang, C.P. (1987), The adsorption of heavy metals onto hydrous activated carbon. Water Research, 21 (9), 1031-1044.

Full Text: W\Wat Res21, 1031.pdf

Abstract: The absorption characteristics of some heavy metals, namely Cu(II), Pb(II), Ni(II) and Zn(II) onto the hydrous activated carbon surface are studied. Carbon type, pH and surface loading are the most important factors affecting the extent of metal removal. The adsorption reaction can be best described by a surface complex formation model. The free metal ions, M²⁺, and their hydroxo species, M(OH)_y^2-y all participate in the absorption reaction. Specific chemical bonding, probably hydrogen bonding provided the sole energy needed for adsorption reaction.

Keywords: Adsorption, Surface Complexes, Activated Carbon, Heavy Metals, Surface Loading

Tan, T.C. and Teo, W.K. (1987), Combined effect of carbon dosage and initial adsorbate concentration on the adsorption isotherm of heavy metals on activated carbon. Water Research, 21 (10), 1183-1188.

Full Text: W\Wat Res21, 1183.pdf

Abstract: The adsorption of dissolved chromium and lead ions by powdered activated carbons significantly depends on the pH, initial adsorbate concentration and carbon dosage. Freundlich and Langmuir equations were unable to describe adequately the observed isotherms under the combined influence of both the carbon dosage and initial adsorbate concentration. These equations were modified and the resulting equations were found to correlate well with the experimental equilibrium data. The modified Langmuir equation gave an overall mean ratio of calculated to experimental adsorptive capacity of 1.001 compared with 1.046 given by the modified Freundlich equation for a total of 135 sets of equilibrium data obtained at different carbon dosages and initial adsorbate concentrations.

Keywords: Metal Ion Adsorption, Carbon, Adsorption Isotherms

Srivastava, S.K., Pant, N. and Pal, N. (1987), Studies on the efficiency of a local fertilizer waste as a low cost adsorbent. Water Research, 21 (11), 1389-1394.

Full Text: W\Wat Res21, 1389.pdf

Abstract: Waste slurry, generated in local fertilizer plants, is converted into activated carbon in air, steam and nitrogen atmospheres. Products so obtained have been characterized and utilized for the removal of phenols, especially 2,4-dinitrophenol. Investigations include the effect of pH, kinetics of adsorption and the effect of salts on the uptake of DNP. Carbon prepared in air exhibits good sorption capacity for DNP and the adsorption data follows both Langmuir and Freundlich models. Some experiments have also been performed with a view to recover phenols and have in situ regeneration of spent carbon column. It is observed that 5% NaOH removes almost 96% of phenol loaded on the carbon column and a treatment with 1 M HNO₃ reactivates the adsorbent particles which can be used for 6–10 cycles at a stretch.

Keywords: Activated Carbon Systems, Carbon, Adsorbent, Activated Carbon Columns

McKay, G., El-Geundi, M. and Nassar, M.M. (1987), Equilibrium studies during the removal of dyestuffs from aqueous solutions using bagasse pith. Water Research, 21 (12), 1513-1520.

Full Text: W\Wat Res21, 1513.pdf

Abstract: The adsorption of four dyestuffs, namely, Basic Blue 69 (BB69), Basic Red 22 (BR22), Acid Red 114 (AR114) and Acid Blue 25 (AB25), onto bagasse pith has been studied. Bagasse pith is a cheap, abundant waste product from the sugar industry in Egypt and was found to have the following monolayer equilibrium saturation capacities: 158, 77, 23 and 22 mg dye g^-1 pith.

The effects of pith particle size range and dye solution temperature were studied. The equilibrium data were analysed using Langmuir, Freundlich and Jossens isotherms.

Keywords: Equilibrium Isotherms, Bagasse Pith, Dyestuffs, Adsorption Capacity

McKay, G. and Bino, M.J. (1988), Adsorption of pollutants from waste water onto activated carbon based on external mass transfer and pore diffusion. Water Research, 22 (3), 279-286.

Full Text: W\Wat Res22, 279.pdf

Abstract: The adsorption of four pollutants in aqueous solutions onto activated carbon has been studied. The following solutes have been investigated, phenol, p-chlorophenol, sodium dodecyl sulphate and mercuric ions. The kinetics were studied using an agitated batch adsorber and a model was proposed, based on external mass transfer and pore diffusion. The model presented has a rapid analytical solution and is based on the assumption of a pseudo-irreversible (rectangular) isotherm.

Keywords: Adsorption, Carbon, Mass Transport, Phenol, Mercuric Ions, Sodium Dodecyl Sulphate, P-Chlorophenol

Toller, G. and Flaim, G.M. (1988), A filtering unit for the removal of pesticide residues from aqueous solutions. Water Research, 22 (5), 657-661.

Full Text: W\Wat Res22, 657.pdf

Abstract: Pesticide loss during filling and washing spray tanks can be considerable especially where cooperative pesticide distribution centres exist (up to 200 1000-litre tanks daily). A filtering unit using readily available organic media (peat, moss and manure) was designed to filter out a variety of commonly-used pesticides in apple orchards. Each filtering unit received residues from 20 pesticide applications consisting of a typical pesticide treatment schedule for apples. Initial concentration of the pesticides in the wastewater was between 26 and 1820 mg 1^-1. Average removal efficiencies were > 99% for dodine. copper oxychloride, azinphos methyl, triadimefon, bitertanol, dithianon, fenarimol, chlorpyrifos ethyl, cyhexatin, benzomate, dinocap and benomyl. Removal efficiency for vamidothion averaged 61%; removal for sulphur was 73%. Bioassays with Daphnia magna and Gloeosporium sp. were performed to evaluate effluent toxicity.

Keywords: Wastewater Treatment, Adsorption, Pesticides, Insecticides, Fungicides, Filtering Unit, Metabolites, Bioassays

? Xue, H.B., Stumm, W. and Sigg, L. (1988), The binding of heavy metals to algal surfaces. Water Research, 22 (7), 917-926.

Full Text: 1988\Wat Res22, 917.pdf

Abstract: Biological particles can profoundly influence the distribution of heavy metals in natural waters because the functional groups on the cell surfaces are able to bind metal ions. The interaction of Cu(III) and Cd(II) was evaluated from titration of algal suspensions (Chlamydomonas rheinhardii) (i) at a constant pH with increments of metal ions and (ii) in the presence of the metal ions with increments of acid. A voltammetric methodology was developed to measure (without prior separation of the solid phase) the metal ions in solution in the presence of algae and to assess the binding of metals to the surfaces of algae. The surfaces of algal cells have a high affinity for Cu(II) and Cd(II), even in the presence of 10⁻³ M Ca²⁺; their functional group ligands can compete with soluble complex formers typically present in natural waters. The adsorption of metals is readily interpreted in terms of surface complex formation equilibria or—mathematically equivalent—Langmuir type adsorption equilibria. The ‘average’ conditional equilibrium constant extracted from the experimental data permits a generalization valid for a certain range of metal surface loading and can be used in multi-metal multi-ligand speciation calculations. Under-standably, the data cannot be fitted over a large range of free metal ion concentrations or metal loading of the surface because the tendency to form surface complexes decreases with increasing metal loading, because there are a variety of surface ligands, and the metal ions bind first to the surface groups with highest affinity and subsequently to groups with lower affinity. A much better fit of the data is obtained if models are used with more than one adjustable constant such as the constant capacitance or the Fowler Guggenheim Frumkin model or a two-site Langmuir isotherm. The kinetics of adsorption and uptake of Cu(II) to Chlamydomonas is characterized by the establishment of a relatively fast pseudo-adsorption equilibrium with the surface that is followed by slow diffusion-controlled uptake into the inside of the cell.

Wong, M.K., Gan, L.M. and Koh, L.L. (1988), Temperature effects on the leaching of lead from unplasticized polyvinyl-chloride pipes. Water Research, 22 (11), 1399-1403.

Full Text: W\Wat Res22, 1399.pdf

Abstract: The leaching of lead from unplasticized poly(vinyl chloride) pipes under different temperatures and by different extractants was studied. The extractants used were tap water, sodium hydrogen carbonate and disodium hydrogen phosphate solutions. The results show that for tap water and sodium hydrogen carbonate extractants, increasing the temperature generally increases the leaching rate of lead. The reverse was observed for the phosphate extractant. The study also shows that the extrusion temperature of the pipes affects the leaching rate of lead by water. Less lead is leached from pipes extruded at higher temperature.

Keywords: Unplasticized Poly(Vinyl Chloride) Pipes, Lead, Water, Leaching, Extraction, Extrusion, Temperature Effect

McKay, G., El-Geundi, M. and Nassar, M.M. (1988), External mass transport processes during the adsorption of dyes onto bagasse pith. Water Research, 22 (12), 1527-1533.

Full Text: W\Wat Res22, 1527.pdf

Abstract: The kinetics of the adsorption of four dyestuffs onto bagasse pith has been studied. Two basic dyes, Basic Blue 69 and Basic Red 22, and two acid dyes, Acid Blue 25 and Acid Red 114, were used in an agitated batch adsorber. The effect of agitation, initial dye concentration, pith mass, pith particle size and dye solution temperature were investigated. A model is proposed to determine the external mass transfer coefficients, k_f, for the systems and these are correlated with the system variable by the following equation: k_f = A(variable)^B.

Keywords: Dyestuffs, Adsorption, Mass Transfer, Bagasse Pith

Wolborska, A. (1989), Adsorption on activated carbon of p-nitrophenol from aqueous solution. Water Research, 23 (1), 85-91.

Full Text: W\Wat Res23, 85.pdf

Abstract: A method of the fixed-bed adsorption on activated carbon has been used in the removal of p-nitrophenol from water. The range of low concentrations of a break-through curve has been analyzed. On the basis of a three-stage model of the process the equations describing the initial stage of the adsorption dynamics and concentration distribution in the bed at low concentrations of the break-through curve have been derived. The equations were used to determine the effective kinetic coefficient and to evaluate the effect of axial diffusion on the process kinetics. A method for determination of the time for protective action of the adsorbent layer has been proposed.

Keywords: Adsorption, Water Purification, Activated Carbon, Break-Through Curve, Fixed-Bed Adsorption, Concentration Distribution, Adsorption From Solution, Mass Transfer Coefficient

Tsezos, M. and Bell, J.P. (1989), Comparison of the biosorption and desorption of hazardous organic pollutants by live and dead biomass. Water Research, 23 (5), 561-568.

Full Text: W\Wat Res23, 561.pdf

Abstract: The adsorption and desorption of lindane, diazinon, pentachlorophenol and 2-chlorobiphenyl by living and dead cells of the fungus R. arrhizus and activated sludge was studied. A generalization concerning the relative magnitude of biosorptive uptake between live and dead biomass cannot be made using the experimental data. Uptakes by live and dead cells are similarly correlated to the octanol/water partition coefficient of the organic pollutants. The desorption of the organic pollutants is not always complete. A part of the observed biosorptive uptake can be attributed to the cell walls of the microbial biomass.

Keywords: Biosorption, Adsorption, Organic, Pollutants, Activated Sludge, Desorption, Fate

Couillard, D., Gariépy, S. and Tran, F. (1989), Slaughterhouse effluent treatment by thermophilic aerobic process. Water Research, 23 (5), 573-579.

Full Text: W\Wat Res23, 573.pdf

Abstract: A pig slaughterhouse effluent was submitted to laboratory runs in order to assess the potentiality of the thermophilic aerobic process for the treatment of meat processing industry’s effluents. A mixed aerobic bacterial culture was successfully maintained at 52 and 58°C in a semi-continuously fed bioreactor, without recycling the cells. Operation was conducted at 6, 12, 18, 24 and 30 h of solids retention time. Over 93% of the CODs (Chemical Oxygen Demand) were removed during the treatment at 52°C for all the retention times investigated, as compared to 86% of removal at 58°C, with an exception for the case of 6 h retention time. Reduction of phosphorus in the form of orthophosphate ranged between 72–90% with the best efficiency noted at 52°C and 6 h retention time. Extremely high specific utilization rates (q_m) were observed and revealed that the process is about 10 times faster than the mesophilic process for slaughterhouse effluent treatment. Biokinetics parameters _m (maximal specific growth rate) and k_d (endogenous respiration coefficient) were evaluated by fitting to appropriate mathematical models. They were found superior to those reported in the literature for mesophilic process, with the exception of the Y (actual yield) coefficient which is of the same magnitude. High k_d values had a marked effect on the apparent yield of sludges which showed low values as compared to those found in mesophilic systems.

Keywords: Thermophilic, Aerobic, Bacteria, Activated Sludge, Slaughterhouse, Mixed Culture, Orthophosphate, Kinetics, Ammonia, Microbial

Srivastava, S.K., Tyagi, R. and Pant, N. (1989), Adsorption of heavy metal ions on carbonaceous material developed from the waste slurry generated in local for tiliser plants. Water Research, 23 (9), 1161-1165.

Full Text: W\Wat Res23, 1161.pdf

Abstract: The waste slurry generated in fertilizer plants in India has been converted into a cheap carbonaceous adsorbent material. This product exhibits a good adsorption potential for chromium, mercury and lead, significant uptake of copper and molybdenum but is a poor scavenger for cadmium, nickel, cobalt and zinc. Isotherms have been used to obtain the thermodynamic parameters of the process. Some column studies have also been performed with a view to recovering the metal ions and have an in situ chemical regeneration of the adsorbent material.

Keywords: Metal Ion Adsorption, Activated Carbon, Recycling Fertilizer Waste

? Sotelo, J.L., Beltrán, F.J., Benitez, F.J. and Beltrán-Heredia, J. (1989), Henry’s law constant for the ozone-water system. Water Research, 23 (10), 1239-1246.

Full Text: 1989\Wat Res23, 1239.pdf

Abstract: Ozone absorption in water in the presence of several salts has been studied in an agitated tank. The influence of the operating variables: ionic strength, temperature, pH, gas flow rate, ozone partial pressure and agitation speed, on the dissolved ozone concentration has been investigated. From an ozone balance in the reactor, the liquid phase volumetric mass transfer coefficient and the equilibrium ozone concentration were calculated.

Finally, equations for the Henry’s law constant as a function of temperature, pH and ionic strength for every salt have been deduced. These equations reproduce the experimental results with deviations less than ±15%. The equations allow us to know the ozone solubility for a given operating condition.

Keywords: Ozone, Ozone Solubility, Absorption, Ionic Strength, Water Ozonation

Notes: highly cited

Gupta, G.S., Prasad, G. and Singh, V.N. (1990), Removal of chrome dye from aqueous solutions by mixed adsorbents: Fly ash and coal. Water Research, 24 (1), 45-50.

Full Text: W\Wat Res24, 45.pdf

Abstract: The removal of Omega Chrome Red ME (a popular chrome dye) from its aqueous solutions by adsorption on a homogeneous mixture of fly ash and coal in different proportions has been carried out. It has been noted that low adsorbate concentration, small particle size of adsorbent, low temperature and acidic medium favour the removal of the dye. A 100% removal of the said dye was achieved at 10 mg1^-1, 30°C, 2.0 pH and 53 m particle size, using a 1: 1 ratio of fly ash and coal. The kinetics and mass transfer studies were made using the models suggested by Lagergren and McKay et al. respectively. The equilibrium data fit well in the Langmuir model of adsorption, showing the formation of monolayer coverage of dye molecules at the outer surface of the adsorbent. Effect of temperature was explained on the basis of solubility and chemical potential of the adsorbate. An attempt has been made to explain the results thus obtained on the basis of various physiochemical properties of the solid-solution interface involved in the process of removal.

Keywords: Chrome Dye, Fly Ash, Coal, Adsorption Kinetics, Pore Diffusion, Mass Transfer and Langmuir’s Model

Huang, C.P., Huang, C.P. and Morehart, A.L. (1990), The removal of Cu(II) from dilute aqueous solutions by Saccharomyces cerevisiae. Water Research, 24 (4), 433-439.

Full Text: W\Wat Res24, 433.pdf

Abstract: Biosorption of Cu(II) by virgin or treated unicellular yeast, Saccharomyces cerevisiae, was studied. Cu(II) adsorption is strongly affected by pH. A given amount of protein is released from live cells upon interactions with metal ions. This decreases the amount of Cu(II) uptake and is most pronounced at high pH values. Adsorption takes place on multisites and can be analyzed by Scatchard plots. Cu(II) uptake by live yeast was biphasic and consisted of an initial, rapid surface binding of Cu(II) followed by a second, slower intracellular uptake of Cu(II). Cu(II) uptake by dead yeast and Cd(II), Pb(II) uptake by live yeast takes place only via surface binding. In a total of 30 mol/g Cu(II) uptake by live yeast, 7 mol/g can be attributed to the intracellular uptake.

A sand column with immobilized S. cerevisiae can completely remove metals before the breakpoint. After the breakpoint, a significant amount of Cu(II) removal over a long period was observed. This is thought to be the result of intracellular uptake. Strong acid can be used to strip the Cu(II)-laden column for reuse.

The result shows that a Cu(II)-laden column can be stripped of adsorbed Cu(II) with one volume of acid (5×10^-3 M HClO₄) per 20 volumes of Cu(II) containing solution.

Keywords: Biosorption, Saccharomyces Cerevisiae, Yeast, Heavy Metals, Copper(II)

Kim, B.R., Anderson, S.G. and Zemla, J.F. (1990), Effect of biological treatments on COD adsorption. Water Research, 24 (4), 457-461.

Full Text: W\Wat Res24, 457.pdf

Abstract: A simulated wastewater, which contains eight metal cutting fluids, was treated using three biological schemes: anaerobic, anaerobic followed by aerobic and aerobic. Sludge ages for the biological schemes were sufficiently long to produce the effluents in which the residual organics were practically nonbiodegradable. Adsorption isotherms, obtained using the wastewater and the three biologically treated effluents, revealed that the absorption capacity of activated carbon increased substantially after the wastewater was biologically treated. This increase appeared to be due to selective, biological removal of poorly adsorbable organics, displaying a synergistic relationship between adsorption and biodegradation.

The organic compositions in the anaerobic/aerobic effluent and in the aerobic effluent might be similar because the adsorption isotherms for the effluents were virtually identical.

Keywords: Adsorption, Chemical Oxygen Demand, Metal Cutting Fluids, Activated Carbon, Anaerobic Treatment, Aerobic Treatment, Isotherms

Martin, R.J. and Shackleton, R.C. (1990), Comparison of two partially activated carbon fabrics for the removal of chlorine and other impurities from water. Water Research, 24 (4), 477-484.

Full Text: W\Wat Res24, 477.pdf

Abstract: Experimental studies were undertaken at the University of Birmingham to investigate and compare the use of two partially activated carbon fabrics for the removal of chlorine and other impurities from potable water in domestic point-of-use water filters. Since the implementation of the EEC drinking water quality directive in July 1985, there has been a marketing surge in domestic water filters, generally aimed at improving taste (the taste of chlorine is frequently cited). The fabrics were observed to be very effective at removing chlorine from water; their dechlorinating powers were significantly superior to that of the granular activated carbon used for comparison. The fabrics were observed to be much less effective at removing phenol, methylene blue and colour.

Keywords: Activated Carbon, Fabric Filters, Domestic Water Filters, Point-of-Use Water Filters, Dechlorination, Taste Removal, Drinking Water Quality

? Matthews, R.W. (1990), Purification of water with near-U.V. illuminated suspensions of titanium dioxide. Water Research, 24 (5), 653-660.

Full Text: 1990\Wat Res24, 653.pdf

Abstract: Benzoic acid, salicyclic acid, phenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, nitrobenzene, methanol, ethanol, acetic acid and formic acid in aerated, aqueous suspensions of TiO₂ were illuminated with near u.v. light. Each solute was present over a range of concentration; generally 1–50 mg 1⁻¹. The rate of oxidation to carbon dioxide was measured at each concentration. The dependence of the rate on concentration obeyed simple Langmuir-Hinshelwood (L-H) kinetics for each solute. Empirical constants have been determined enabling the prediction of mineralization rates at any solute concentration in 0.1% (w/w) TiO₂ suspensions. The integrated L-H rate expression gives reasonable agreement with observed time-dependent CO₂ formation curves. A comparison was made between CO₂ formation rate using 4-chlorophenol illuminated with artificial and natural u.v. light. The results indicate that 90% mineralization of all the solutes except formic acid initially present as 50 mg solute 1⁻¹ suspension occurs within 2–3 h with 1 m² of sunlight. Formic acid was mineralized at approximately twice the rate of the other solutes.