Personal Research Database

Full Text: W\Wat Sci Tec43, 59.pdf

Abstract: Extracellular polymeric substances (EPSs) were extracted by high-speed centrifugation at 20,000 G for 30 min from an activated sludge treating municipal wastewater. Each gram of sludge, as measured in volatile suspended solids (VSS), contained 7.3 mg of EPS, including 6.5 mg of protein (EPSp) and 0.8 mg of carbohydrate (EPS,). The EPS, had a mean MW of 2.0×10⁵; about 18% of EPSp had MW over 5×10⁴ and 16% below 5×10³. For heavy metal concentrations ranging 10-100 mg/l, EPS on average removed 99% of Zn²⁺, 98% of Cu²⁺, 97% of Cr³⁺, 85% of Cd²⁺, 69% of Co²⁺, 37% of Ni²⁺, and 26% of CrO₄^2-. The relative degrees of metal removals were inconsistent with those reported for the activated sludge process. Each mg of ESP had the capacity to remove up to 1.48 mg of Zn²⁺, 1.12 mg of Cu²⁺, 0.83 mg of Cr³⁺, 0.90 mg of Cd²⁺, 1.10 mg of Co²⁺, 0.25 mg each of Ni²⁺ and CrO₄^2-. Results suggest the feasibility of recovering ESP from waste sludge for use as adsorbent. Freundlich isotherm correlated satisfactorily with the adsorption data of Ni²⁺, Cu²⁺. Cd²⁺, and CrO₄^2- (R2 ranging 0.39-0.97), whereas Langmuir isotherm correlated satisfactorily with those of Zn²⁺, Cr³⁺ and Ni²⁺ (R² ranging 0.93-0.96). Both correlated poorly for those of Co²⁺.

Keywords: Activated Sludge, Adsorption, Eps, Extracellular Polymeric Substances, Heavy Metals, Bacterial Extracellular Polymers, Z-Ramigera, Zoogloea-Ramigera, Ions, Extraction, Culture, Removal

? Yoo, C.K., Cho, J.H., Kwak, H.J., Choi, S.K., Chun, H.D. and Lee, I. (2001), Closed-loop identification and control application for dissolved oxygen concentration in a full-scale coke wastewater treatment plant. Water Science and Technology, 43 (7), 207-214.

Full Text: 2001\Wat Sci Tec43, 207.pdf

Abstract: The objective of this paper is to apply a closed-loop identification to actual dissolved oxygen control system in the coke wastewater treatment plant. It approximates the dissolved oxygen dynamics to a high order model using the integral transform method and reduces it to the first-order plus time delay (FOPTD) or second-order plus time delay (SOPTD) for the PID controller tuning. To experiment the process identification on the real plant, a simple set-point change of the speed of surface aerator under the closed-loop control without any mode change was used as an activation signal of the identification. The full-scale experimental results show a good identification performance and a good tracking ability for set-point change. As a result of improved control performance, the fluctuation of dissolved oxygen concentration variation has been decreased and the electric power saving has been accomplished.

Keywords: Autotuning, Closed-Loop Identification, Dissolved Oxygen, FOPTD Model, PID Controller, PID Controllers, SOPTD Model, Wastewater, Wastewater Treatment

Zouboulis, A.I., Matis, K.A., Rousou, E.G. and Kyriakidis, D.A. (2001), Biosorptive flotation for metal ions recovery. Water Science and Technology, 43 (8), 123-129.

Full Text: W\Wat Sci Tec43, 123.pdf

Abstract: The solid/liquid separation of suspended. metals-loaded biomass was studied extensively by successfully applying flotation. Industrial non-living biomass samples of different origin have been tried in the laboratory as sorbents of metal ions, with the main stress on Streptomyces rimosus, an effective actinomyces. Flotation was used as the harvesting technique downstream, following the biosorption stage. Important parameters of the investigation were the solution pH, the surfactant type and concentration, the applied modification of biomass, etc. The reuse and recycling of biosorbent following elution was proved possible. As a result cleaned water was produced as underflow of the flotation process.

Keywords: Biomass, Biosorption, Copper, Harvesting, Nickel, Zinc, Removal, Cadmium

Beccari, M., Majone, M., Papini, M.P. and Torrisi, L. (2001), Enhancement of anaerobic treatability of olive oil mill effluents by addition of Ca(OH)₂ and bentonite without intermediate solid/liquid separation. Water Science and Technology, 43 (11), 275-282.

Full Text: W\Wat Sci Tec43, 275.pdf

Abstract: Previous work on the anaerobic treatment of olive oil mill effluents (OME) have shown: (a) lipids, even if more easily degraded than phenols, were potentially capable of inhibiting methanogenesis more strongly; (b) a pretreatment based on addition of Ca(OH), and bentonite removed lipids almost quantitatively; (c) preliminary biotreatability tests performed on the pretreated OME showed high bloconversion into methane at very low dilutions ratios, especially when the mixture (OME, Ca(OH), and bentonite) was fed to the biological treatment without providing an intermediate phase separation. This paper was directed towards two main aims: (a) to optimize pretreatment: the best results in terms of methane production were obtained by addition of Ca(OH)₂ UP to pH 6.5 and of 10 g L^-1 of bentonite; (b) to evaluate the enhancement of anaerobic treatability of OME pretreated under optimized conditions in a lab-scale continuous mathanogenic reactor fed with the substrate without intermediate solid/liquid separation: very satisfactory performances were obtained (at an organic load of 8.2 kg COD m^-3 d^-1 and at a dilution ratio of 1: 1.5 total COD removal was 91%, biogas production was 0.80 g CH4 (as COD)/g tot. COD, lipids removal was 98%, phenols removal was 63%). The results confirm the double role played by bentonite (adsorption of the inhibiting substances and release of the adsorbed biodegradable matter in the methanogenic reactor).

Keywords: Anaerobic Digestion, Olive Oil Mill Effluents, Integration of Chemico-Physical and Biological, Processes, Bentonite, Fatty-Acids, Digestion

de Victorica, J. and Galvan, M. (2001), Pseudomonas aeruginosa as an indicator of health risk in water for human consumption. Water Science and Technology, 43 (12), 49-52.

Full Text: W\Wat Sci Tec43, 49.pdf

Abstract: During an outbreak of gastroenteritis in 28 children living in a small neighbourhood of Cuernavaca city (Mexico), a survey was performed to evaluate the confidence in coliform bacteria as sole indicators of potability of drinking waters. A primary infection by E coli and a secondary by Pseudomonas aeruginosa was diagnosed in five of the children and the drinking water provided by a well was suspected as a transmission source. General and household distribution systems, household filters and bottled waters were evaluated for total and faecal coliforms, family Enterobacteriaceae, P aeruginosa and residual chlorine. In every sample, pathogenic/opportunistic bacteria were isolated even in the absence of coliforms and in the presence of residual chlorine. Arbitrarily assigned ‘pollution/risk levels’ indicated that the most elevated risk was most frequently associated with storage in tanks and with bacterial colonisation in the pipeline system and commercial household filters where high levels of P aeruginosa were determined. A probability of correspondence between the presence of this bacterium and the secondary gastrointestinal infection diagnosed was found pointing towards a need for the inclusion of other microorganisms, one of which may be P aeruginosa, as indicators of health risk associated with drinking waters in Mexico.

Keywords: Coliform Indicators, Drinking Water, Drinking Water Standards, Health Risk, Pseudomonas aeruginosa

Notes: highly cited

? van Dongen, U., Jetten, M.S.M. and van Loosdrecht, M.C.M. (2001), The SHARON^-Anammox^ process for treatment of ammonium rich wastewater. Water Science and Technology, 44 (1), 153-160.

Full Text: 2001\Wat Sci Tec44, 153.pdf

Abstract: The treatment of ammonium rich wastewater, like sludge digester effluent, can be significantly improved when new biotechnological processes are introduced. In this paper, the combination of a partial nitrification process (SHARON (R)) and anoxic ammonium oxidation (Anammox (R)) process for the treatment of ammonia rich influents is evaluated. Herein the combined process has been studied with sludge recycle liquor from the WWTP Rotterdam-Dokhaven. The SHARON process was:operated stably for more than 2 years in a 10 l CSTR under continuous aeration with a HRT of 1 day. The ammonia in the sludge liquor was converted by 53% to nitrite only. During the test period no formation of nitrate was observed. The effluent of the SHARON process was ideally suited as influent for the Anammox reactor. The Anammox process was operated as a granular sludge SBR-process. More than 80% of the ammonia was converted into dinitrogen gas at a load of 1.2 kgN/m(3) per day. Planctomycete-like bacteria dominated the mixed community of the Anammox reactor, and only a small percentage of the population consisted of aerobic ammonium-oxidizing bacteria. This showed that the ammonium-oxidizers in the effluent of the SHARON process did not accumulate in the SBR. The test period showed that the combined SHARON-Anammox system can work stably over long periods and the process is ready for full-scale implementation.

Keywords: Partial Nitrification, Nitrite, Aerobic And Anaerobic Ammonium Oxidation, Sludge Liquor, Sharon, Anammox, Nitrogen Removal, Oxidation, Reactor, System, Diversity, Sludge, Water

? Awuah, E., Anohene, F., Asante, K., Lubberding, H. and Gijzen, H. (2001), Environmental conditions and pathogen removal in macrophyte- and algal-based domestic wastewater treatment systems. Water Science and Technology, 44 (6), 11-18.

Full Text: 2001\Wat Sci Tec44, 11.pdf

Abstract: The environmental conditions and pathogen removal in macrophyte (Pistia stratiotes and Lemna paucicostata) and algal-based wastewater treatment systems were determined over a period of 29 days under tropical conditions. The experiment was conducted on a batch scale in 4.5 plastic containers immersed in moist sand beds. A control of raw sewage stored under dark conditions was included. Environmental conditions such as pH, temperature DO and conductivity and heterotrophic and faecal enterococci populations were monitored five times a week at 8, 12 and 20 GMT. BOD was monitored once a week for five weeks. Average temperatures within the systems ranged between 28.3 degreesC in the control to 30.6 degreesC In the algal-based system. Low pH levels of pH of 4.5 and DO levels of 3 mg/L were recorded in the water lettuce treatment systems. High pH levels around 10.5 and DO levels of about 20 mg/L were observed in the algal-based system. The control and duckweed system remained neutral. All treatment systems performed equally well fn pathogen removal and BOD reduction. The BOD decreased from 130mg/L to 5.0, 7.5, 10 and 15 mg/L in the duckweed, water lettuce, control and algal based treatment systems respectively. The faecal enterococci population decreased from 1.1810⁵ /ml to values below 100/ml in all treatment systems.

Keywords: Duckweed, Faecal Enterococci, Macrophytes, Pathogen Removal, Pistia, Pistia Stratiotes, Stabilization Ponds, Wastewater, Wastewater Treatment, Water Treatment

Haytoglu, B., Demirer, G.N. and Yetis, U. (2001), Effectiveness of anaerobic biomass in adsorbing heavy metals. Water Science and Technology, 44 (10), 245-252.

Full Text: W\Wat Sci Tec44, 245.pdf

Abstract: This study focuses on the effectiveness of waste anaerobic dead biomass (AIDE) in adsorbing heavy metals, namely Pb(II), Cr(VI), Cu(II), Ni(II) and Zn(II). The metal uptake capacity of ADB was investigated and compared with the values for various biomass types from the literature. The biomass, which was grown under laboratory conditions using a synthetic wastewater, was used throughout the study after sterilization. The maximum metal adsorptive capacities were evaluated by running isotherm tests at 25 degreesC and initial pH of 4. It was observed that Pb(II) was adsorbed with the highest capacity. The maximum adsorptive capacity of ADB for Pb(II), Zn(II), Cu(II), Ni(II) and Cr(VI) was determined as 1250, 625, 357, 227 and 384 mg/g dry biomass, respectively. These values were significantly higher than the corresponding capacities reported in the literature for other types of biomass. In describing the adsorption equilibrium, both the Langmuir and Freundlich isotherm models were examined. The experimental data for Pb(II), Zn(II), Cr(VI), and Ni(II) fitted both the Langmuir and Freundlich models with correlation coefficients of 0.80-0.99 while Cu(II) only fitted the Langmuir model with a correlation coefficient of 0.99. Therefore, different and distinct aspects of the interactions between the cell surfaces and the metal ions might have occurred for Cu(II) and the rest of the metals. The equilibrium pH values attained were all higher than the initial pH value of 4.0, and this indicated that both the type and the initial concentration of the metal influenced the equilibrium pH. Furthermore, there was a decrease in equilibrium pH with increasing initial metal concentration at varying levels.

Keywords: Anaerobic Sludge, Binding Capacity, Biosorption, Heavy Metals, pH, Immobilized Fungal Biomass, Aqueous-Solutions, Activated-Sludge, Marine-Algae, Cell-Walls, Biosorption, Removal, Adsorption, Digestion, Cadmium

Weng, C.H., Chang, E.E. and Chiang, P.C. (2001), Characteristics of new coccine dye adsorption onto digested sludge particulates. Water Science and Technology, 44 (10), 279-284.

Full Text: W\Wat Sci Tec44, 279.pdf

Abstract: The adsorption characteristics of an anionic azo dye (new coccine) onto digested sludge have been studied. Results show that the dye can effectively be removed by sludge. It was found that the adsorption rate is very rapid and the equilibrium can be reached in 10 min. The adsorption kinetics can be expressed by the modified Freundlich equation. Also, the solution pH, ionic strength, and temperature are the key factors affecting the adsorption. The effect of electrical double layer thickness on the adsorption was also discussed. The adsorption standard free energy, enthalpy, and entropy were determined. The adsorption follows a nonlinear multilayer adsorption isotherm. The specific surface area of sludge was determined as 82 similar to 150 m²/g on the basis of its monolayer dye adsorption capacity.

Keywords: Adsorption, Dye, Sludge, Specific Surface Area, Activated-Sludge, Surface-Area

Dierks, S. (2001), Investigation of copper adsorption to peat using the simple metal sorption model. Water Science and Technology, 44 (11-12), 477-483.

Full Text: W\Wat Sci Tec44, 477.pdf

Abstract: The Simple Metal Sorption (SiMS) equilibrium model was used to simulate the proton/cation exchange behavior of peat with dissolved copper. The SiMS model represents proton binding and metal binding as cation exchange for heterogeneous sorbents as a function of pH, salt concentration, total metal concentration and total ligand concentration. The SiMS model uses fewer parameters than other cation exchange models for multidimensional datasets and can be executed on a standard spreadsheet. The cation exchange selectivity coefficient, K-Me, K-app, is represented as K-Me, K-app = K-Me(H⁺)(alpha)(L-T/Me-T)I-beta(phi). The model is similar to standard surface complexation approaches, with an intrinsic relationship described by mass action laws (K-Me = metal equilibrium constant) and variable terms that are expressed as simple power functions of proton concentration, ligand to metal ratio (L-T/Me-T), and ionic strength (I). The model successfully simulated the proton exchange behavior of acid-washed, Sphagnum peats over a range of 4 to 8 pH units with ionic strength differing by three orders of magnitude (I = 0.001 to 0.1). Simulation of copper binding on five peat data sets and the dried biomass of Potamogeton lucens was also successful (0.94 < r² < 0.99). However, there was no apparent relationship between model parameters and peat characteristics. Incorporation of the SiMS model into a framework for predicting metals removals in wetlands will require more work.

Keywords: Cation Exchange Selectivity Coefficient, Ion-Exchange, Peat, Surface Complexation Model, Ions, Moss

? Kao, C.M., Wang, J.Y., Lee, H.Y. and Wen, C.K. (2001), Application of a constructed wetland for non-point source pollution control. Water Science and Technology, 44 (11-12), 585-590.

Full Text: 2001\Wat Sci Tec44, 585.pdf

Abstract: In Taiwan, non-point source (NPS) pollution is one of the major causes of impairment of surface waters. The main objective of this study was to evaluate the efficacy of using constructed wetlands on NPS pollutant removal and water quality improvements. A field-scale constructed wetland system was built inside the campus of National Sun Yat-Sen University (located in southern Taiwan) to remove (1) NPS pollutants due to the stormwater runoff, and (2) part of the untreated wastewater from school drains. The constructed wetland was 40 m (L) x 30 m (W) x 1 m (D), which received approximately 85 m(3) per day of untreated wastewater from school drainage pipes. The plants grown on the wetland included floating (Pistia stratiotes L.) and emergent (Phragmites communis L.) species. One major storm event and baseline water quality samples were analyzed during the monitoring period. Analytical results indicate that the constructed wetland removed a significant amount of NPS pollutants and wastewater constituents. More than 88% of nitrogen, 81% of chemical oxygen demand (COD), 85% of heavy metals, and 60% of the total suspended solids (TSS) caused by the storm runoff were removed by the wetland system before discharging. Results from this study may be applied to the design of constructed wetlands for NPS pollution control and water quality improvement.

Keywords: Constructed Wetland, Constructed Wetlands, Non-Point Source Pollutants, Pistia Stratiotes, Pollution, Wastewater Treatment, Water Quality, Wetland

Pinisakul, A., Polprasert, C., Parkpian, P. and Satayavivad, J. (2002), Arsenic removal efficiency and mechanisms by electro-chemical precipitation process. Water Science and Technology, 46 (9), 247-254.

Full Text: W\Wat Sci Tec46, 247.pdf

Abstract: This research was conducted to investigate the efficiency and mechanisms of arsenic (As) removal from a contaminated water by using the electro-chemical precipitation (ECP) process, with the operating conditions as follows: initial As concentration of 0.5-5 mg/L, 0.1 M KCl, electrical gradient of 200 V/m and initial pH higher than 3. The laboratory-scale ECP unit was able to reduce As to within the WHO drinking water standard of 0.01 mg/L in 20 min. The Cl^- salt was found to yield better As removal efficiencies than the NO₃^- salt probably because NO₃^- ions interfered with the production of OH^- and Fe(OH)₃ important for As removal. X-ray fluorescence and X-ray diffractometric analysis revealed maghemite (Fe₂O₃) and angelellite (Fe₄As₂O11,) to be the major compounds present in the precipitated sludge. The percent Fe₂O, and Fe₄AS₂O₁₁ contents of the dried ECP sludge were 98.29% and 0.26%, respectively. From a mass balance analysis, As removal in the ECP process was due to: incorporation in and adsorption on the ECP sludge - 64.9-94.9%, conversion to arsine (AsH₃) gas - 10.5-15.6%, adsorption on the electrode plates and reactor walls - 0.03-1.1 %, residual in the supernatant - 0.2-0.4%, and unaccounted for 1.2-19.8%.

Keywords: Arsenic Removal, Electrochemical Precipitation, Electrolysis, Heavy Metal Removal, Electrochemical Precipitation, Water, Groundwater

? Salim, M.R., Othman, F., Ali, M.I., Patterson, J. and Hardy, T. (2002), Application of locally available materials for the treatment of organic polluted water. Water Science and Technology, 46 (9), 339-346.

Full Text: 2002\Wat Sci Tec46, 339.pdf

Abstract: Several types of water treatment technologies including adsorption are how being used to treat polluted water. In this paper the removal of phenol by adsorption will be discussed. Activated carbons are successfully applied for purification of potable water and the removal of organic pollutants in wastewater. This paper is concerned with a low cost approach to treating waste water that is significant especially for those countries where oil palm is an available agricultural product like Malaysia, Ivory Coast, Nigeria, Thailand, Papua New Guinea. In the coastal region coconut is an available agricultural product and activated carbon prepared using coconut shell is also an economical method of water treatment. The materials used in this study were Commercial Activated Carbon (CAC), prepared from coconut shell and Modified Oil Palm Shell (MOPAS) of 1 to 2 mm diameters. The surface area of CAC and MOPAS was 38.5 m²/g and 38.2 m²/g respectively and the iodine number was determined as 674 and 454 for CAC and MOPAS, respectively. From the study the result shows above 70% removal efficiency for 5 mg/L and 40% removal efficiency for 20 mg/L of phenol solution. The performance efficiency will be discussed based on batch test, following Freundlich adsorption isotherm. The results indicate that CAC exhibits a higher adsorptive capacity (K-f of 0.079) as compared to MOPAS (K-f of 0.048). Hence a better removal efficiency for CAC at lower concentration of phenol. Results from column tests show a better adsorptive capacity for CAC (2.73) as compared to MOPAS (2.48).

Keywords: Adsorption, Adsorption Kinetic, Breakthrough Time, Freundlich Isotherm, Modified Oil Palm Shell, Phenol, Treatment, Wastewater

Annadurai, G., Juang, R.S. and Lee, D.J. (2003), Adsorption of heavy metals from water using banana and orange peels. Water Science and Technology, 47 (1), 185-190.

Full Text: W\Wat Sci Tec47, 185.pdf

Abstract: Liquid-phase adsorption removal of Cu²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Pb²⁺ in the concentration range of 5-25 mg/L using low-cost banana and orange peel wastes was examined at 30 C. Under comparable conditions, the amount of adsorption decreased in the order Pb²⁺ > Ni²⁺ > Zn²⁺ > Cu²⁺ > Co²⁺ for both adsorbents. The adsorption isotherms could be better described by the Freundlich equation. The amount of adsorption increased with increasing pH and reached a plateau at pH > 7, which was confirmed by the variations of zeta potentials. The application potential of such cellulose-based wastes for metal removal (up to 7.97 mg Pb²⁺ per gram of banana peel at pH 5.5) at trace levels appeared to be promising.

Keywords: Adsorption, Adsorption Removal, Aqueous-Solution, Carbon, Copper, Fruit Peels, Heavy Metals, Ions, Isotherms, Orange Peel, Peel, Removal, Waste-Water, Zeta Potentials

? Lee, K.M. and Lim, P.E. (2003), Treatment of phenolic wastewater using agricultural wastes as an adsorbent in a sequencing batch reactor. Water Science and Technology, 47 (10), 41-47.

Full Text: 2003\Wat Sci Tec47, 41.pdf

Abstract: The objective of this study is to investigate the potential of the activated rice husk to be used as an alternative adsorbent to powdered activated carbon (PAC) in the simultaneous adsorption and biodegradation processes under sequencing batch reactor (SBR) operation to Treat synthetic wastewater containing phenol; p-methylphenol, p-ethylphenol and p-isopropylphenol. The rice husk (PRH) was activated by pyrolysis at 600 C for 5 hours in a nitrogen atmosphere. Using the Langmuir model the limiting. adsorption capacities of PRH for the phenols were found to vary from 0.015-0.05 of those of PAC. The SBR reactors with and without adsorbent addition were operated with fill, react, settle, draw and idle periods in the ratio of 4:6:1:0.75:0.25 for a cycle time of 12 hours. For phenolic wastewater containing, 1,200 mg/L phenol, 1,200 mg/L p-methylphenol, 800 mg/L p-ethylphenol and 650 mg/L p-isopropylphenol, it was found that the biodegradation process alone was unable to produce effluent of quality which would satisfy the discharge standards of COD less than or equal to 100 mg/L and phenol concentration (_)less than or equal to 1 mg/L. The Addition of PAC in the ratio of PAC/phenolic compound at 0.095 g/g for phenol, 0.119 g/g for p-methylphenol, 0.179 g/g for p-ethylphenol and 0.220 g/g for p-isopropylphenol, can improve the effluent quality to satisfy the discharge standards. Equivalent treatment performance was achieved with the use of PRH at dosages of 2-3 times higher than those of PAC for all the phenolic wastewater studied. The increased adsorption capacity of PRH shown in the treatment indicates bioregeneration of the adsorbed surface during the treatment process.

Keywords: Adsorption, Agricultural Wastes, Powdered Activated Carbon, SBr, Sequencing Batch Reactor, Sludge, Treatment, Wastewater

Rae, I.B. and Gibb, S.W. (2003), Removal of metals from aqueous solutions using natural chitinous materials. Water Science and Technology,