Personal Research Database

Full Text: 2005\Wat Res39, 4961.pdf

Abstract: Microbial fuel cells (MFCs) represent a new method for treating animal wastewaters and simultaneously producing electricity. Preliminary tests using a two-chambered MFC with an aqueous cathode indicated that electricity could be generated from swine wastewater containing 8320 +/- 190 mg/L of soluble chemical oxygen demand (SCOD) (maximum power density of 45 mW/m(2)). More extensive tests with a single-chambered air cathode MFC produced a maximum power density with the animal wastewater of 261 mW/m(2) (200 Omega resistor), which was 79% larger than that previously obtained with the same system using domestic wastewater (146 +/- 8 mW/m(2)) due to the higher concentration of organic matter in the swine wastewater. Power generation as a function of substrate concentration was modeled according to saturation kinetics, with a maximum power density of P-max = 225 mW/m(2) (fixed 1000 Omega resistor) and half-saturation concentration of K-s = 1512 mg/L (total COD). Ammonia was removed from 198 +/- 1 to 34 +/- 1 mg/L (83% removal). In order to try to increase power output and overall treatment efficiency, diluted (1:10) wastewater was sonicated and autoclaved. This pretreated wastewater generated 16% more power after treatment (110 +/- 4 mW/m(2)) than before treatment (96 +/- 4 mW/m(2)). SCOD removal was increased from 88% to 92% by stirring diluted wastewater, although power output slightly decreased. These results demonstrate that animal wastewaters such as this swine wastewater can be used for power generation in MFCs while at the same time achieving wastewater treatment. (c) 2005 Elsevier Ltd. All rights reserved.

Keywords: Microbial Fuel Cell, Electricity, Swine Wastewater, Animal Wastewater, Power Generation, Intermittent Aeration, Hydrogen-Production, Removal, Manure, Reactor, Energy, Power, Denitrification, Phosphorus, Nitrogen

? Deschamps, E., Ciminelli, V.S.T. and Höll, W.H. (2005), Removal of As(III) and As(V) from water using a natural Fe and Mn enriched sample. Water Research, 39 (20), 5212-5220.

Full Text: 2005\Wat Res39, 5212.pdf

Abstract: The arsenic removal capacity of a natural oxide sample consisting basically of Mn-minerals (birnessite, cryptomelane, todorokite), and Fe-oxides (goethite, hematite), collected in the Iron Quadrangle mineral province in Minas Gerais, Brazil, has been investigated. As-spiked tap water and an As-rich mining effluent with As-concentrations from 100 μg L⁻¹ to 100 mg L⁻¹ were used for the experiments. Sorbent fractions of different particle sizes (<38 μm to 0.5 mm), including spherical material (diameter 2 mm), have been used. Batch and column experiments (pH values of 3.0, 5.5, and 8.5 for batch, and about pH 7.0 for column) demonstrated the high adsorption capacity of the material, with the sorption of As(III) being higher than that of As(V). At pH 3.0, the maximum uptake for As(V) and for As(III)-treated materials were 8.5 and 14.7 mg g⁻¹, respectively. The Mn-minerals promoted the oxidation of As(III) to As(V), for both sorbed and dissolved As-species. Column experiments with the cFeMn-c sample for an initial As-concentration of 100 μg L⁻¹ demonstrated a very efficient elimination of As(III), since the drinking water limit of 10 g L⁻¹ was exceeded only after 7400 BV total throughput. The As-release from the loaded samples was below the limit established by the toxicity characteristic leaching procedure, thus making the spent material suitable for discharge in landfill deposits.

Keywords: Arsenic, Arsenic Removal, Arsenic Sorption, Iron–Manganese Sorbent

? Shilton, A.N., Elmetri, I., Drizo, A., Pratt, S., Haverkamp, R.G. and Bilby, S.C. (2006), Phosphorus removal by an ‘active’ slag filter-a decade of full scale experience. Water Research, 40 (1), 113-118.

Full Text: 2006\Wat Res40, 113.pdf

Research on active filters for P removal using steel slag material has been conducted in laboratories across the world, however, field experiments have been limited and long-term data is practically non-existent. This paper presents a decade of experience on P removal by active slag filters at a full-scale treatment plant. During 1993-1994 the filter removed 77% of the total phosphorus (TP), and over the first 5 years of the filter’s operation it reduced the mean effluent TP concentration to 2.3 mg l(-1). However during the sixth year of operation P removal was significantly reduced. Over the 11 years of monitoring, 22.4 tonnes of TP was removed by the filter, 19.7 tonnes of this in the first 5-year period. It was determined that the slag material maintained its maximum removal potential until reaching a P-retention ratio of 1.23kg TP per tonne of slag. This paper provides the first long-term field data for slag filters, and shows that they can provide P removal for a half a decade before filter replacement/rejuvenation is required. (c) 2005 Elsevier Ltd. All rights reserved.

Keywords: Active Filter, Adsorption, Blast-Furnace Slag, Constructed Reed Beds, Media, Monitoring, Phosphorus, Phosphorus Removal, Plant, Ponds, Ratio, Research, Retention Capacity, Sands, Slag, Steel Slag, Systems, Treatment, Treatment Wetlands, Waste-Water, Wastewater, Wastewater Treatment

? Ho, Y.S. (2006), Second-order kinetic model for the sorption of cadmium onto tree fern: A comparison of linear and non-linear methods. Water Research, 40 (1), 119-125.

Full Text: 2006\Wat Res40, 119.pdf; 2005\Wat Res-Ho1.pdf; 2005\Wat Res-Ho.pdf

Abstract: A comparison was made of the linear least-squares method and a trial-and-error non-linear method of the widely used pseudo-second-order kinetic model for the sorption of cadmium onto ground-up tree fern. Four pseudo-second-order kinetic linear equations are discussed. Kinetic parameters obtained from the four kinetic linear equations using the linear method differed but they were the same when using the non-linear method. A type 1 pseudo-second-order linear kinetic model has the highest coefficient of determination. Results show that the non-linear method may be a better way to obtain the desired parameters.

Keywords: Biosorption, Kinetics, Pseudo-Second-Order, Tree Fern, Metal

? Beolchini, F., Pagnanelli, F., Toro, L. and Vegliò, F. (2006), Ionic strength effect on copper biosorption by Sphaerotilus natans: Equilibrium study and dynamic modelling in membrane reactor. Water Research, 40 (1), 144-152.

Full Text: 2006\Wat Res40, 144.pdf

Abstract: Biosorption of copper by Sphaerotilus natans in different conditions of ionic strength and pH was studied by performing sorption tests in batch and membrane reactors. Equilibrium batch tests evidenced the negative effect of ionic strength and the positive effect of pH on biosorption performances: the highest determined value for copper specific uptake, q, was about 60 mg/g at pH 6 and about 15 mg/g at pH 4. A competitive equilibrium model was successfully fitted to experimental data at different ionic strength levels to account for copper–sodium competition. In membrane reactor tests, experimental profiles of copper concentration in the permeate vs. time did not evidence a significant effect of ionic strength at low pH values (4 and 5). On the other hand a more remarkable effect of ionic strength on copper concentration in the permeate was observed at pH 6. Experimental profiles of continuous biosorption in the membrane reactors were successfully simulated by developing a dynamic model accounting for Cu–Na competition and for binding ability of cells fragments.

Keywords: Copper, Biosorption, Membrane, Equilibrium, Kinetics, Modelling

? Vilar, V.J.P., Botelho, C.M.S. and Boaventura, R.A.R. (2006), Equilibrium and kinetic modelling of Cd(II) biosorption by algae Gelidium and agar extraction algal waste. Water Research, 40 (2), 291-302.

Full Text: 2006\Wat Res40, 291.pdf

Abstract: In this study an industrial algal waste from agar extraction has been used as an inexpensive and effective biosorbent for cadmium(II) removal from aqueous solutions. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction. Equilibrium data follow both Langmuir and Redlich–Peterson models. The parameters of Langmuir equilibrium model are q_max = 18.0 mg g⁻¹, b = 0.19 mg l⁻¹, and q_max = 9.7 mg g⁻¹, b = 0.16 mg l⁻¹, respectively for Gelidium and the algal waste. Kinetic experiments were conducted at initial Cd(II) concentrations in the range 6–91 mg l⁻¹. Data were fitted to pseudo-first- and second-order Lagergren models. For an initial Cd(II) concentration of 91 mg l⁻¹ the parameters of the pseudo-first-order Lagergren model are k_1,ads = 0.17 and 0.87 min⁻¹; q_eq = 16.3 and 8.7 mg g⁻¹, respectively, for Gelidium and algal waste. Kinetic constants vary with the initial metal concentration. The adsorptive behaviour of biosorbent particles was modelled using a batch reactor mass transfer kinetic model. The model successfully predicts Cd(II) concentration profiles and provides significant insights on the biosorbents performance. The homogeneous diffusivity, Dh, is in the range 0.5–2.2×10⁻⁸ and 2.1–10.4×10⁻⁸ cm² s⁻¹, respectively, for Gelidium and algal waste.

Keywords: Biosorption, Cadmium(II), Gelidium, Agar Extraction Waste, Mass Transfer Modelling

? Seredyńska-Sobecka, B., Tomaszewska, M., Janus, M. and Morawski, A.W. (2006), Biological activation of carbon filters. Water Research, 40 (2), 355-363.

Full Text: 2006\Wat Res40, 355.pdf

Abstract: To prepare biological activated carbon (BAC), raw surface water was circulated through granular activated carbon (GAC) beds. Biological activity of carbon filters was initiated after about 6 months of filter operation and was confirmed by two methods: measurement of the amount of biomass attached to the carbon and by the fluorescein diacetate (FDA) test. The effect of carbon prewashing on WG-12 carbon properties was also studied. For this purpose, the nitrogen adsorption isotherms at 77K and Fourier transform-infrared (FT-IR) spectra analyses were performed. Moreover, iodine number, decolorizing power and adsorption properties of carbon in relation to phenol were studied. Analysis of the results revealed that after WG-12 carbon prewashing its BET surface increased a little, the pH value of the carbon water extract decreased from 11.0 to 9.4, decolorizing power remained at the same level, and the iodine number and phenol adsorption rate increased. in preliminary studies of the ozonation-biofiltration process, a model phenol solution with concentration of approximately 10mg/l was applied. During the ozonation process a dose of 1.64 mgO₃/mgTOC (total organic carbon) was employed and the contact time was 5 min. Four empty bed contact times (EBCTs) in the range of 2.4-24.0 min were used in the biofiltration experiment. The effectiveness of purification was measured by the following parameters: chemical oxygen demand (CODMn), TOC, phenol concentration and UV254-absorbance. The parameters were found to decrease with EBCT. (c) 2005 Elsevier Ltd. All rights reserved.

Keywords: Agricultural By-Products, Biological Activated Carbon, Bioregeneration, Kinetics, Microbial Activity, Ozonation, Performance, Sorption, Water

? Song, Z., Edwards, S.R. and Burns, R.G. (2006), Treatment of naphthalene-2-sulfonic acid from tannery wastewater by a granular activated carbon fixed bed inoculated with bacterial isolates Arthrobacter globiformis and Comamonas testosteroni. Water Research, 40 (3), 495-506.

Full Text: 2006\Wat Res40, 495.pdf

Abstract: The kinetics of naphthalene-2-sulfonic acid (2-NSA) adsorption by granular activated carbon (GAC) were measured and the relationships between adsorption, desorption, bioavailability and biodegradation assessed. The conventional Langmuir model fitted the experimental sorption isotherm data and introduced 2-NSA degrading bacteria, established on the surface of the GAC, did not interfere with adsorption. The potential value of GAC as a microbial support in the aerobic degradation of 2-NSA by Arthrobacter globiformis and Comamonas testosteroni was investigated. Using both virgin and microbially colonised GAC, adsorption removed 2-NSA from the liquid phase up to its saturation capacity of 140 mg/g GAC within 48 h. However, between 83.2% and 93.3% of the adsorbed 2-NSA was bioavailable to both bacterial species as a source of carbon for growth. In comparison to the non-inoculated GAC, the combination of rapid adsorption and biodegradation increased the amount (by 70–93%) of 2-NSA removal from the influent phase as well as the bed-life of the GAC (from 40 to >120 d). A microbially conditioned GAC fixed-bed reactor containing 15 g GAC removed 100% 2-NSA (100 mg/l) from tannery wastewater at an empty bed contact time of 22 min for a minimum of 120 d without the need for GAC reconditioning or replacement. This suggests that small volume GAC bioreactors could be used for tannery wastewater recycling.

Keywords: Tannery Wastewater, Naphthalene-2-Sulfonic Acid, Biodegradation, Sorption, Bioavailability, GAC, Arthrobacter, Comamonas, Desulphurisation

? Pokhrel, D. and Viraraghavan, T. (2006), Arsenic removal from an aqueous solution by a modified fungal biomass. Water Research, 40 (3), 549-552.

Full Text: 2006\Wat Res40, 549.pdf

Abstract: Non-viable fungal biomass of Aspergillus niger, coated with iron oxide was investigated for its potential to remove arsenic from an aqueous solution. A. niger biomass coated with iron oxide showed maximum removal (approximately 95% of As(V) and 75% of As(III)) at a pH of 6. No strong relationship was observed between the surface charge of the biomass and arsenic removal.

Keywords: Arsenic Removal, Fungal Biomass, Aspergillus Niger, Iron Oxide Coating

? Lo, I.M.C., Lam, C.S.C. and Lai, K.C.K. (2006), Hardness and carbonate effects on the reactivity of zero-valent iron for Cr(VI) removal. Water Research, 40 (3), 595-605.

Full Text: 2006\Wat Res40, 595.pdf

Abstract: Zero-valent iron (Fe0) was used to remove hexavalent chromium, Cr(VI), in groundwater via a coupled reduction-oxidation reaction. Nine columns were set up under various groundwater geochemistry to investigate the effects of hardness and carbonate on Cr(VI) removal. The Cr(VI) removal capacity of Fe0 was found to be about 4 mg Cr/g Fe0 in the control column (i.e., column 1). A slight decrease in the Cr(VI) removal capacity was found in the presence of calcium hardness. However, there was a 17% drop in the Cr(VI) removal capacity when magnesium hardness was present at low to moderately hard level. Results also revealed that carbonate changed the morphology of the Fe0 by formation of pale green precipitates on the iron filings. Furthermore, there was a 33% decrease in the Cr(VI) removal capacity of Fe0 when both carbonate and hardness ions were present. In general, the presence of hardness ions and carbonate in groundwater have great impact on the Fe0 by formation of passivated precipitates, such as CaCO₃, on the Fe0 surface resulting in a diminished lifespan of the Fe0 by blocking electron transfer.

Keywords: Carbonate, Chromium, Hardness, Reactivity, Zero-Valent Iron

? Oladoja, N.A. and Ademoroti, C.M.A. (2006), The use of fortified soil-clay as on-site system for domestic wastewater purification. Water Research, 40 (3), 613-620.

Full Text: 2006\Wat Res40, 613.pdf

Abstract: The quest for simple, low-cost and high-performance decentralized wastewater treatment system for domestic application in developing nations necessitated this study. Clay samples collected from different deposits in Nigeria were characterized by studying the mineralogical and geochemical composition using X-ray diffraction (XRD) and atomic absorption spectroscopy (AAS), respectively. Three major clay minerals of kaolinite, illite and smectite were identified. The geochemical studies showed the abundance of SiO₂, Al₂O₃ and H₂O+ in each of the clay samples. Performance efficiency studies were conducted to determine the best combination ratio of pebbles/soil-clay. Soil-clay fortified by pebbles in combination ratios of 1:3 (i.e. pebbles:soil-clay=1:3 (w/w) showed the optimum water purification, while the combination 3:1 gave the least. The flow rate studies showed that the wastewater had a longer residence time in non-fortified soil-clay than in fortified soil-clay. Two modes of treatment methods were employed—single and double column treatment methods (SCT and DCT). The two methods gave effluents of good quality characteristics, but those from the DCT were of better quality. The quality of effluents also varies from one clay type to another. The quality of effluents from media containing smectite clay mineral was better than those from other columns. Repeated usage of the fortified clay column showed a decrease of pH, TS and DO, and an increase of COD when monitored over a period of 10 days.

Keywords: Fortified Soil-Clay, Wastewater Treatment, Percolator, Single Column, Double Column

? Ambonguilat, S., Gallard, H., Garron, A., Epron, F. and Croué, J.P. (2006), Evaluation of the catalytic reduction of nitrate for the determination of dissolved organic nitrogen in natural waters. Water Research, 40 (4), 675-682.

Full Text: 2006\Wat Res40, 675.pdf

Abstract: The catalytic reduction of nitrate ions into nitrogen gas was tested to partly remove dissolved inorganic nitrogen (DIN) before the determination of dissolved organic nitrogen (DON). Experiments were conducted on nitrate solutions enriched with natural organic matter (NOM) isolates previously extracted from surface waters. Three catalysts Pd-In/Al2O3, Pd-Sn/Al2O3 and Pd/SnO2 were tested. Their noble metal (palladium) and promoter metal (indium or tin) contents are 5 and 1.75wt%, respectively. Preliminary experiments performed on a solution containing 17 amino acids showed that most compounds were removed by less than 15%, probably due to sorption onto the catalysts, Reduction of nitrate in absence of NOM was complete after 20 min of reaction time and the removal of DIN was about 80% (about 19% formation of ammonium). In the presence of NOM (DOC 20mgC/L, DON 0.67mg N/L), the kinetic of nitrate reduction was slower and the reduction in DIN content was limited to 15% i.e. selectivity toward ammonium reached 85%. Adsorption tests showed a similar removal of both DOC and DON of about 70% and 30% onto Pd-Sn/Al2O3 and Pd/SnO2 catalysts, respectively, which confirmed that NOM probably compete with nitrate for active catalytic sites. In conclusion, catalytic reduction of nitrate before DON determination cannot be used because of DON sorption and low DIN removal. (c) 2005 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Catalytic Reduction, Copper, Dissolved Organic Nitrogen, Drinking-Water, Evaluation, Ions, Natural Organic Matter, Nitrate, Nitrite, Nitrogen, Palladium, Platinum, Reduction, Removal, Sorption, Surface

Notes: highly cited

? Rosenberger, S., Laabs, C., Lesjean, B., Gnirss, R., Amy, G., Jekel, M. and Schrotter, J.C. (2006), Impact of colloidal and soluble organic material on membrane performance in membrane bioreactors for municipal wastewater treatment. Water Research, 40 (4), 710-720.

Full Text: 2006\Wat Res40, 710.pdf

Abstract: Two parallel membrane bioreactors (2 m(3) each) were operated over a period of 2 years. Both pilots were optimised for nitrification, denitrification, and enhanced biological phosphorous elimination, treating identical municipal wastewater under comparable operating conditions. The only constructional difference between the pilots was the position of the denitrification zone (pre-denitrification in pilot 1 and post-denitrification in pilot 2). Despite identical modules and conditions, the two MBRs showed different permeabilities and fouling rates. The differences were not related to the denitrification scheme. In order to find an explanation for the different membrane performances, a one-year investigation was initiated and the membrane performance as well as the operating regime and characteristics of the activated sludge were closely studied. MLSS concentrations, solid retention time, loading rates, and filtration flux were found not to be responsible for the different performance of the submerged modules. These parameters were kept identical in the two pilot plants. Instead, the non-settable fraction of the sludges (soluble and colloidal material, i.e. polysaccharides, proteins and organic colloids) was found to impact fouling and to cause the difference in membrane performance between the two MBR. This fraction was analysed by spectrophotometric and size exclusion chromatography (SEC) methods. In a second step, the origin of these substances was investigated. The results point to microbiologically produced substances such as extracellular polymeric substances (EPS) or soluble microbial products (SMP). (c) 2005 Elsevier Ltd. All rights reserved.

Keywords: Membrane Bioreactor, Fouling, Organic Substances, Solutes, Sec, Polysaccharides, Extracellular Polymeric Substances, Activated-Sludge, Microbial Products, Filtration Characteristics, Permeate Flux, System

? Lv, L.A., He, J., Wei, M., Evans, D.G. and Duan, X. (2006), Uptake of chloride ion from aqueous solution by calcined layered double hydroxides: Equilibrium and kinetic studies. Water Research, 40 (4), 735-743.

Full Text: 2006\Wat Res40,735.pdf

Abstract: Layered double hydroxides (LDH) calcined within a certain temperature range (denoted as CLDH) have been shown to recover their original layered structure in the presence of appropriate anions. in the light of this so-called ‘memory effect’, uptake of chloride ion from aqueous solution by calcined MgAl-CO₃ LDH was investigated in batch mode. The equilibrium isotherm showed that the uptake of chloride ion by CLDH was consistent with the Langmuir and Freundlich equations and that the Langmuir model gave a better fit to the experimental data than the Freundlich model. The maximum uptake capacity of CLDH for chloride ion was 149.5 mg/g, close to the stoichiometric uptake (168 mg/g). The influence of varying pH of solution, initial chloride concentration, adsorbent quantity, and temperature on the kinetics of chloride removal has also been explored. Four kinetic models were used to fit the experimental data, and it was found that the pseudo - second-order kinetics model could be used to describe the uptake process satisfactorily. The calculated value of E. was found to be 56.8kJ/mol, which suggests that the process of uptake of chloride ion is controlled by the rate of reaction of chloride ion with the CLDH rather than diffusion. A mechanism for removal of chloride ion has been confirmed by X-ray diffraction, FT-IR spectroscopy and TG-MS measurements. (c) 2005 Elsevier Ltd. All rights reserved.

Keywords: Chloride, Kinetics, Layered Double Hydroxides, Hydrotalcite, Memory Effect, Isotherm, Magnesium-Aluminum Oxide, Waste-Water, Activated Carbon, Diffusion-Model, Sodium-Chloride, Basic Dye, Adsorption, Sorption, Removal, Hydrotalcite

? Zhang, Y. and Banks, C. (2006), A comparison of the properties of polyurethane immobilised Sphagnum moss, seaweed, sunflower waste and maize for the biosorption of Cu, Pb, Zn and Ni in continuous flow packed columns. Water Research, 40 (4), 788-798.

Full Text: 2006\Wat Res40, 788.pdf

Abstract: The biosorption of Cu, Pb, Zn and Ni from a mixed solution of the metals was investigated in continuous flow packed columns containing polyurethane immobilised biomass. The characteristics and biosorption properties of Sphagnum moss, the brown seaweed Ascophyllum nodosum, waste biomass from the preparation of sunflower oil, and whole plant maize were compared.

All the biomass types showed a preference for the sequestration of Pb followed by Cu, with Ni and Zn having roughly equal affinity. With continuous metal loading to the column there was an initial binding of all metals and then a displacement of the lower affinity metals by those with a high affinity. This led to a chromatographic effect in the column with breakthrough concentrations for low-affinity metals higher than the concentration in the feed. A similar phenomenon was found on desorption using acidic solutions where low-affinity metals were desorbed preferentially. The results also indicated that despite competitive displacement of one metal species by another the biomass appeared to succeed in retaining some low-affinity metal species indicating that there may be selective sites present with different affinity characteristics.

When using a multi-metal solution with Cu, Pb, Zn and Ni at equal 10 mg g⁻¹ concentrations as column influent, the total quantities of metal sequestered were: seaweed, 117.3 mg g⁻¹; sunflower waste, 33.2 mg g⁻¹; Sphagnum moss, 32.5 mg g⁻¹; and maize, 2.3 mg g⁻¹. The use of an acid base potentiometric titration showed a relationship between the number of acid functional groups and biosorption capacity, although this was not proportional for the biomass types studied. It can, however, be used in conjunction with a simple classification of metals into high and low-affinity bands to make a preliminary assessment of a biosorption system.

Keywords: Biosorption, Multi-Metal, Biosorption Capacity, Biosorption Affinity

? Tang, Z.J., Hong, S., Xiao, W.Z. and Taylor, J. (2006), Impacts of blending ground, surface, and saline waters on lead release in drinking water distribution systems. Water Research,