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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2010.04.012 Byline: A. Duran, J.M. Monteagudo, I. San Martin, M. Aguirre Abstract: The aim of this work was to study the mineralization of wastewater effluent from an integrated-gasification combined-cycle (IGCC) power station sited in Spain to meet the requirements of future environmental legislation. This study was done in a pilot plant using a homogeneous photo-Fenton oxidation process with continuous addition of H.sub.2O.sub.2 and air to the system. The mineralization process was found to follow pseudo-first-order kinetics. Experimental kinetic constants were fitted using neural networks (NNs). The NNs model reproduced the experimental data to within a 90% confidence level and allowed the simulation of the process for any values of the parameters within the experimental range studied. At the optimum conditions (H.sub.2O.sub.2 flow rate=120mL/h, [Fe(II)]=7.6mg/L, pH=3.75 and air flow rate=1m.sup.3/h), a 90% mineralization was achieved in 150min. Determination of the hydrogen peroxide consumed and remaining in the water revealed that 1.2mol of H.sub.2O.sub.2 was consumed per each mol of total organic carbon removed from solution. This result confirmed that an excess of dissolved H.sub.2O.sub.2 was needed to achieve high mineralization rates, so continuous addition of peroxide is recommended for industrial application of this process. Air flow slightly improved the mineralization rate due to the formation of peroxo-organic radicals which enhanced the oxidation process. Author Affiliation: Department of Chemical Engineering, Grupo IMAES Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, Avda. Camilo Jose Cela 3, 13071 Ciudad Real, Spain Article History: Received 6 November 2009; Revised 25 March 2010; Accepted 19 April 2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2010.03.016 Byline: Natalia C. Archilha (a), Catarina S.A. Canto (a), Suzana M. Ratusznei (a), Jose A.D. Rodrigues (a), Marcelo Zaiat (b), Eugenio Foresti (b) Abstract: The objective of this work was to analyze the effect of the interaction between feeding strategy and COD/sulfate ratio on the removal efficiency of sulfate and organic matter from a synthetic wastewater. An anaerobic sequencing batch reactor with recirculation of the liquid phase and containing immobilized biomass on polyurethane foam (AnSBBR) was used. The AnSBBR with a total volume of 3.7L, treated 2.0L synthetic wastewater in 8-h cycles at 30[+ or -]1[degrees]C and was inoculated with anaerobic biomass from a UASB. Two feeding strategies were assessed: (a) batch and (b) batch followed by fed-batch. In strategy (a) the reactor was fed in 10min with 2L wastewater containing sulfate and carbon sources. In strategy (b) 1.2L wastewater (containing only the sulfate source) was fed during the first 10min of the cycle and the remaining 0.8L (containing only the carbon source) in 240min. The COD/sulfate ratios assessed were 1 and 3. Based on these values and on the concentrations of organic matter (0.5-11.25gCOD/L) and sulfate (0.5 and 2.5gSO.sub.4.sup.2-/L), the sulfate and organic matter loading rates applied equaled 1.5 and 4.5gSO.sub.4.sup.2-/Ld for sulfate and 1.5, 4.5 and 13.5gCOD/Ld for organic matter. After stabilization of the system time profiles were run of monitored parameters (COD, sulfate, sulfide and sulfite). In general, the reactor showed to be robust for use in the anaerobic treatment of wastewaters containing sulfate. Gradual feeding (strategy b) of the carbon source favored sulfate reduction, resulting in sulfate removal efficiencies of 84-98% and organic matter removal efficiencies of 48-95%. The best results were observed under COD/sulfate ratio equal to 1 (loading rates of 1.5 and 4.5gSO.sub.4.sup.2-/Ld for sulfate, and 1.5 and 4.5gCOD/Ld for organic matter). When COD/sulfate ratio was 3 (loading rates of 1.5and 4.5gSO.sub.4.sup.2-/Ld for sulfate, and 4.5 and 13.5gCOD/Ld for organic matter) the effect of feed mode became less significant. These results show that the strategy batch followed by fed-batch is more advantageous for COD/sulfate ratios near the stoichiometric value (0.67) and higher organic matter and sulfate concentrations. Author Affiliation: (a) Escola de Engenharia Maua - Instituto Maua de Tecnologia (EEM/IMT), Praca Maua 1, CEP 09.580-900, Sao Caetano do Sul - SP, Brazil (b) Departamento de Hidraulica e Saneamento - Escola de Engenharia de Sao Carlos - Universidade de Sao Paulo (SHS/EESC/USP), Av. Trabalhador Sao-Carlense 400, CEP 13566-590, Sao Carlos - SP, Brazil Article History: Received 14 May 2009; Revised 11 March 2010; Accepted 26 March 2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2010.03.009 Byline: Tim Rixen (a), Antje Baum (a), Harni Sepryani (b), Thomas Pohlmann (c), Christine Jose (b), Joko Samiaji (b) Abstract: The Siak is a typical, nutrient-poor, well-mixed, black water river in central Sumatra, Indonesia, which owes its brown color to dissolved organic matter (DOM) leached from surrounding, heavily disturbed peat soils. We measured dissolved organic carbon (DOC) and oxygen concentrations along the river, carried out a 36-h experiment in the province capital Pekanbaru and quantified organic matter and nutrient inputs from urban wastewater channels into the Siak. In order to consider the complex dynamic of oxygen in rivers, a box-diffusion model was used to interpret the measured data. The results suggest that the decomposition of soil derived DOM was the main factor influencing the oxygen concentration in the Siak which varied between [approximately equal to]100 and 140 [mu]mol l.sup.-1. Additional DOM input caused by wastewater discharges appeared to reduce the oxygen concentrations by [approximately equal to]20 [mu]mol l.sup.-1 during the peak-time in household water use in the early morning and in the early evening. Associated enhanced nutrient inputs appear to reduce the impact of the anthropogenic DOM by favoring the photosynthetic production of oxygen in the morning. A reduction of 20 [mu]mol l.sup.-1, which although perhaps not of great significance in Pekanbaru, has strong implications for wastewater management in the fast developing areas downstream Pekanbaru where oxygen concentrations rarely exceed 20 [mu]mol l.sup.-1. Author Affiliation: (a) Leibniz-Zentrum fur Marine Tropenokologie, Fahrenheitstr. 6, 28359 Bremen, Germany (b) University of Riau, Jl. Simpang Panam Km 12.5, Pekanbaru, Riau, Indonesia (c) Zentrum fur Meeres- und Klimaforschung, Institut fur Meereskunde, Universitat Hamburg, Bundesstr. 53, 20146 Hamburg, Germany Article History: Received 14 April 2009; Revised 22 January 2010; Accepted 23 March 2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2010.02.021 Byline: Ali Erturk, Melike Gurel, Alpaslan Ekdal, Cigdem Tavsan, Aysegul Ugurluoglu, Dursun Zafer Seker, Aysegul Tanik, Izzet Ozturk Abstract: Istanbul, being one of the highly populated metropolitan areas of the world, has been facing water scarcity since the past decade. Water transfer from Melen Watershed was considered as the most feasible option to supply water to Istanbul due to its high water potential and relatively less degraded water quality. This study consists of two parts. In the first part, water quality data covering 26 parameters from 5 monitoring stations were analyzed and assessed due to the requirements of the 'Quality Required of Surface Water Intended for the Abstraction of Drinking Water' regulation. In the second part, a one-dimensional stream water quality model with simple water quality kinetics was developed. It formed a basic design for more advanced water quality models for the watershed. The reason for assessing the water quality data and developing a model was to provide information for decision making on preliminary actions to prevent any further deterioration of existing water quality. According to the water quality assessment at the water abstraction point, Melen River has relatively poor water quality with regard to NH.sub.4.sup.+, BOD.sub.5, faecal streptococcus, manganese and phenol parameters, and is unsuitable for drinking water abstraction in terms of COD, PO.sub.4.sup.3-, total coliform, total suspended solids, mercury and total chromium parameters. The results derived from the model were found to be consistent with the water quality assessment. It also showed that relatively high inorganic nitrogen and phosphorus concentrations along the streams are related to diffuse nutrient loads that should be managed together with municipal and industrial wastewaters. Author Affiliation: Istanbul Technical University, Faculty of Civil Engineering, 34469 Maslak, Istanbul, Turkey Article History: Received 2 September 2008; Revised 4 February 2010; Accepted 15 February 2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.11.006 Byline: S. Jellali (a), E. Diamantopoulos (b), H. Kallali (a), S. Bennaceur (a), M. Anane (a), N. Jedidi (a) Abstract: The release of excess nitrogen-containing compounds into groundwater is a major concern in aquifer recharge by the Soil Aquifer Treatment (SAT) process. Ammonium (N H.sub.4.sup.+) is one of the most nocive and common nitrogen compounds in wastewaters. In order to assess the risk of wastewater use for aquifer recharge,N H.sub.4.sup.+adsorption onto Souhil wadi soil sampled from the SAT pilot plant (Nabeul, Tunisia) was studied using laboratory columns experiments. Several experiments were conducted using aqueous synthetic solutions under different aqueous ammonium concentrations and flow rates. Furthermore, a real wastewater solution was used to test the effect of competitive cations contents on N H.sub.4.sup.+ adsorption. Afterwards, the Hydrus-1D model was used in inverse mode to simulate the ammonium transport through the Souhil wadi soil. For the synthetic solutions, the adsorbed ammonium amount varied from 1 to 30.7 mg kg.sup.-1 for aqueous ammonium concentrations between 4.9 and 36.4 mg L.sup.-1. The linear isotherm model was found to be the most suitable for describing this adsorption. The flow rate decrease from 45 to 15 mL min.sup.-1 induced an increase in the ammonium adsorption capacity by 49%. Indeed, the lesser the flow rate is, the longer the residence time and the higher the exchange between the aqueous solution and soil matrix. The use of wastewater instead of aqueous synthetic solution decreased about 7 times the Souhil wadi adsorption capacity of ammonium because of its relatively high concentrations of competitive ions such as calcium and magnesium. The use of the Hydrus-1D model showed that the chemical non-equilibrium model was the best to simulate the ammonium transport through the laboratory soil columns. Author Affiliation: (a) Water Research and Technologies Centre (CERTE), Wastewater Treatment and Recycling Laboratory, B.P.273, Soliman 8020, Tunisia (b) Agricultural University of Athens, Department of Natural Resources Management and Agricultural Engineering, 75 Iera Odos Str, 118 55 Athens, Greece Article History: Received 16 May 2009; Revised 4 November 2009; Accepted 27 November 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.09.026 Byline: Seong-Rin Lim (a), Sangwon Suh (b), Jung-Hoon Kim (c), Hung Suck Park (c) Abstract: Urban water planning and policy have been focusing on environmentally benign and economically viable water management. The objective of this study is to develop a mathematical model to integrate and optimize urban water infrastructures for supply-side planning and policy: freshwater resources and treated wastewater are allocated to various water demand categories in order to reduce contaminants in the influents supplied for drinking water, and to reduce consumption of the water resources imported from the regions beyond a city boundary. A case study is performed to validate the proposed model. An optimal urban water system of a metropolitan city is calculated on the basis of the model and compared to the existing water system. The integration and optimization decrease (i) average concentrations of the influents supplied for drinking water, which can improve human health and hygiene; (ii) total consumption of water resources, as well as electricity, reducing overall environmental impacts; (iii) life cycle cost; and (iv) water resource dependency on other regions, improving regional water security. This model contributes to sustainable urban water planning and policy. Author Affiliation: (a) Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, USA (b) Department of Bioproducts and Biosystems Engineering, University of Minnesota, 1390 Eckles Avenue, St. Paul, MN 55108, USA (c) Department of Civil and Environmental Engineering, University of Ulsan, P.O. Box 18, Ulsan 680-749, Republic of Korea Article History: Received 3 April 2009; Revised 11 September 2009; Accepted 21 September 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2009.04.018 Byline: Francesco Mari (a), Lucia Politi (a), Annibale Biggeri (b)(c), Gabriele Accetta (c), Claudia Trignano (d), Marianna Di Padua (a), Elisabetta Bertol (a) Keywords: Waste water; Illicit drugs; 1-year study Abstract: The diffusion and trends in use of each substance is a basic information in policy planning of strategies aiming at deterrence of drug abuse or in the organization of the fight against drug trafficking. The actual diffusion of illicit drugs in a population is hardly measurable, but, among the various measures available, the analysis of waste water plants represents one of the most reliable source of data. We analyzed waste water in order to monitor illicit drug use by local population. We investigated the use of cocaine and heroin in the city of Florence, Italy, over a 1-year (July 2006-June 2007) period using state-of-the-art measuring techniques from waste water samples. Cocaine, benzoylecgonine, and morphine were determined in water samples by gas chromatography-mass spectrometer, and the amount of illicit substance was estimated. Data indicate for cocaine a bimodal distribution (December and March), while heroin showed a main peak in April. The heroin-to-cocaine use ratio in terms of estimated doses per month ranged from 0.11 to 0.76, representing new evidence of wider distribution of cocaine than heroin in Florence. Waste water analysis can become a valuable tool in monitoring use of illicit drugs over time. In particular, it can highlight changes in the magnitude and relative use of illicit drug at a population level thereby becoming useful to develop strategies against drug trafficking and abuse. If routinely performed, it can be part of Epidemiologic Surveillance Programmes on drug abuse. Author Affiliation: (a) Division of Forensic Toxicology, Department of Anatomy, Histology, and Legal Medicine, University of Florence, Viale Morgagni, 85, 50134 Florence, Italy (b) Department of Statistics 'G. Parenti', University of Florence, Italy (c) Biostatistics Unit, ISPO Institute for Cancer Prevention, Florence, Italy (d) Institute of Legal Medicine, University of Sassari, Italy Article History: Received 17 December 2008; Revised 9 April 2009; Accepted 16 April 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.05.032 Byline: J. Medellin-Azuara (a), L.G. Mendoza-Espinosa (b), J.R. Lund (a), J.J. Harou (c), R.E. Howitt (d) Abstract: This paper uses simple hydro-economic optimization to investigate a wide range of regional water system management options for northern Baja California, Mexico. Hydro-economic optimization models, even with parsimonious model formulations, enable investigation of promising water management portfolios for supplying water to agricultural, environmental and urban users. CALVIN, a generalized hydro-economic model, is used in a case study of Baja California. This drought-prone region faces significant challenges to supply water to agriculture and its fast growing border cities. Water management portfolios include water markets, wastewater reuse, seawater desalination and infrastructure expansions. Water markets provide the flexibility to meet future urban demands; however conveyance capacity limits their use. Wastewater reuse and conveyance expansions are economically promising. At current costs desalination is currently uneconomical for Baja California compared to other alternatives. Even simple hydro-economic models suggest ways to increase efficiency of water management in water scarce areas, and provide an economic basis for evaluating long-term water management solutions. Author Affiliation: (a) Department of Civil and Environmental Engineering, Engineering Unit III, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA (b) Instituto de Investigaciones Oceanologicas, Universidad Autonoma de Baja California, Km 107 Carretera Ensenada-Tijuana, Ensenada, Baja California, CP 22800, Mexico (c) UCL Environment Institute, Department of Civil, Environmental & Geomatic Engineering, University College London, Gower Street, London WC1E 6BT, UK (d) Department of Agricultural and Resource Economics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA Article History: Received 15 October 2008; Revised 1 May 2009; Accepted 22 May 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.05.026 Byline: Sardar Khan (a), Irshad Ahmad (b), M. Tahir Shah (b), Shafiqur Rehman (a), Abdul Khaliq (c) Abstract: This study was conducted to investigate the effectiveness of a continuous free surface flow wetland for removal of heavy metals from industrial wastewater, in Gadoon Amazai Industrial Estate (GAIE), Swabi, Pakistan. Industrial wastewater samples were collected from the in-let, out-let and all cells of the constructed wetland (CW) and analyzed for heavy metals such as lead (Pb), cadmium (Cd), iron (Fe), nickel (Ni), chromium (Cr) and copper (Cu) using standard methods. Similarly, samples of aquatic macrophytes and sediments were also analyzed for selected heavy metals. Results indicate that the removal efficiencies of the CW for Pb, Cd, Fe, Ni, Cr, and Cu were 50%, 91.9%, 74.1%, 40.9%, 89%, and 48.3%, respectively. Furthermore, the performance of the CW was efficient enough to remove the heavy metals, particularly Cd, Fe, and Cu, from the industrial wastewater fed to it. However, it is suggested that the metal removal efficiency of the CW can be further enhanced by using proper management of vegetation and area expansion of the present CW. Author Affiliation: (a) Department of Environmental Science, University of Peshawar, Peshawar 25120, Pakistan (b) National Center of Excellence in Geology, University of Peshawar, Pakistan (c) Atomic Energy Commission, REO-Peshawar, PO Box No. 734, University of Peshawar, Pakistan Article History: Received 14 October 2008; Revised 24 April 2009; Accepted 22 May 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.05.016 Byline: Francisco W. Sousa (a), Marcelo James Sousa (a), Isadora R.N. Oliveira (a), Andre G. Oliveira (a), Rivelino M. Cavalcante (a), Pierre B.A. Fechine (a), Vicente O.S. Neto (b), Denis de Keukeleire (c), Ronaldo F. Nascimento (a) Abstract: In this study, sugar cane residue or bagasse was used for removal of toxic metal ions from wastewater of an electroplating factory located in northeast Brazil. Prior acid treatment increased the adsorption efficacies in batch wise experiments. The microstructure of the material before and after the treatment was investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Column operations showed that removals of Cu.sup.2+, Ni.sup.2+ and Zn.sup.2+ from wastewater (in the absence of cyanide) were 95.5%, 96.3.0%, and 97.1%, respectively. Regeneration of the adsorbent obtained in acid indicated that the efficiencies decreased only after the fourth cycle of re-use. Acid-treated sugar cane bagasse can be considered a viable alternative to common methods to remove toxic metal ions from aqueous effluents of electroplating industries. Author Affiliation: (a) Laboratorio de Analise Traco, Departamento de Quimica Analitica e Fisico Quimica, Universidade Federal do Ceara, Campus do Pici, Centro de CiA*ncias, Bloco 940-CEP: 60451-970 Fortaleza, Ceara, Brazil (b) Universidade Estadual do Ceara, Centro de CiA*ncias e Tecnologia. Av. Paranjana, 1700 Campus do Itaperi, 60740-000 Fortaleza, CE - Brazil (c) Ghent University, Faculty of Pharmaceutical Sciences, Harelbekestraat 72, 9000 Ghent, Belgium Article History: Received 15 August 2008; Revised 6 April 2009; Accepted 7 May 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.03.012 Byline: M. Achak, L. Mandi, N. Ouazzani Abstract: The aim of this work was to examine the performance of a sand filter in treating modern olive mill (OMW) effluents after dilution with domestic wastewater on a one-to-one basis. The experimental pilot consisted of a column of opaque PVC, and the sand filter was filled with 50cm of sand and 10cm of gravel in the top and the bottom of the filter. The alimentation (4cm/day) was done sequentially following a 1day wet/3days dry cycle. The OMW effluent was very acidic with a pH of 4.12, and had high concentrations of phenolic compounds (7.2g/L) and total chemical oxygen demand (65g/L). The percolation of the diluted OMW through the sand filters caused an increase in pH from 4.84 to 8.25 and a 90% removal of total suspended solids. The sand filter treatment also led to important reductions in organic matter (90% of total COD, 83% of dissolved COD and 92% of phenolic compounds) and nutrients (91% of Kjeldahl-nitrogen, 97% of ammonia-nitrogen, 99% of nitrate-nitrogen and 99% of phosphates). The flow rate became very low indicating clogging of the sand pores after 10weeks. HPLC analysis of the diluted OMW before and after passage through the sand filter showed an important reduction in the toxic monomeric compounds after the treatment. Author Affiliation: Laboratoire d'Hydrobiologie, d'Ecotoxicologie et d'Assainissment, Universite Cadi Ayyad, Faculte des Sciences Semlalia, Boulevard Prince Moulay-Abdelah, BP. 2390, Marrakech, Morocco Article History: Received 12 August 2008; Revised 19 February 2009; Accepted 19 March 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2008.11.007 Byline: Y.P. Li (a), G.H. Huang (b)(c) Abstract: In water-quality management problems, uncertainties may exist in a number of impact factors and pollution-related processes (e.g., the volume and strength of industrial wastewater and their variations can be presented as random events through identifying a statistical distribution for each source); moreover, nonlinear relationships may exist among many system components (e.g., cost parameters may be functions of wastewater-discharge levels). In this study, an inexact two-stage stochastic quadratic programming (ITQP) method is developed for water-quality management under uncertainty. It is a hybrid of inexact quadratic programming (IQP) and two-stage stochastic programming (TSP) methods. The developed ITQP can handle not only uncertainties expressed as probability distributions and interval values but also nonlinearities in the objective function. It can be used for analyzing various scenarios that are associated with different levels of economic penalties or opportunity losses caused by improper policies. The ITQP is applied to a case of water-quality management to deal with uncertainties presented in terms of probabilities and intervals and to reflect dynamic interactions between pollutant loading and water quality. Interactive and derivative algorithms are employed for solving the ITQP model. The solutions are presented as combinations of deterministic, interval and distributional information, and can thus facilitate communications for different forms of uncertainties. They are helpful for managers in not only making decisions regarding wastewater discharge but also gaining insight into the tradeoff between the system benefit and the environmental requirement. Author Affiliation: (a) College of Urban and Environmental Sciences, Peking University, Beijing 100871, China (b) Environmental Systems Engineering Program, Faculty of Engineering, University of Regina, Regina, Sask S4S 0A2, Canada (c) Chinese Research Academy of Environmental Science, North China Electric Power University, Beijing 100012-102206, China Article History: Received 18 September 2007; Revised 12 October 2008; Accepted 22 November 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2008.08.003 Byline: Rogerio Michelan (b), Thiago R. Zimmer (b), Jose A.D. Rodrigues (a), Suzana M. Ratusznei (a), Deovaldo de Moraes (c), Marcelo Zaiat (b), Eugenio Foresti (b) Abbreviations: COD, chemical oxygen demand; HAc, acetic acid; M, methane; S, substrate; TVA, total volatile acids; tvs, total volatile solids; He70, reactor operated with three-blade-helix impeller and agitation rate of 70rpm; He100, reactor operated with three-blade-helix impeller and agitation rate of 100rpm; Pa50, reactor operated with six-vertical-flat-blade-paddle impeller and agitation rate of 50rpm; Pa75, reactor operated with six-vertical-flat-blade-paddle impeller and agitation rate of 75rpm; Pi50, reactor operated with six-45[degrees]-inclined-flat-blade-paddle impeller and agitation rate of 50rpm; Pi75, reactor operated with six-45[degrees]-inclined-flat-blade-paddle impeller and agitation rate of 75rpm; Ti50, reactor operated with six-45[degrees]-inclined-flat-blade-turbine impeller and agitation rate of 50rpm; Ti75, reactor operated with six-45[degrees]-inclined-flat-blade-turbine impeller and agitation rate of 50rpm; Tu50, reactor operated with six-vertical-flat-blade-turbine impeller and agitation rate of 50rpm Abstract: The effect of flow type and rotor speed was investigated in a round-bottom reactor with 5L useful volume containing 2.0L of granular biomass. The reactor treated 2.0L of synthetic wastewater with a concentration of 800mgCOD/L in 8-h cycles at 30[degrees]C. Five impellers, commonly used in biological processes, have been employed to this end, namely: a turbine and a paddle impeller with six-vertical-flat-blades, a turbine and a paddle impeller with six-45[degrees]-inclined-flat-blades and a three-blade-helix impeller. Results showed that altering impeller type and rotor speed did not significantly affect system stability and performance. Average organic matter removal efficiency was about 84% for filtered samples, total volatile acids concentration was below 20mgHAc/L and bicarbonate alkalinity a little less than 400mgCaCO.sub.3/L for most of the investigated conditions. However, analysis of the first-order kinetic model constants showed that alteration in rotor speed resulted in an increase in the values of the kinetic constants (for instance, from 0.57h.sup.-1 at 50rpm to 0.84h.sup.-1 at 75rpm when the paddle impeller with six-45[degrees]-inclined-flat-blades was used) and that axial flow in mechanically stirred reactors is preferable over radial-flow when the vertical-flat-blade impeller is compared to the inclined-flat-blade impeller (for instance at 75rpm, from 0.52h.sup.-1 with the six-flat-blade-paddle impeller to 0.84h.sup.-1 with the six-45[degrees]-inclined-flat-blade-paddle impeller), demonstrating that there is a rotor speed and an impeller type that maximize solid-liquid mass transfer in the reaction medium. Furthermore, power consumption studies in this reduced reactor volume showed that no high power transfer is required to improve mass transfer (less than 0.6kW/10.sup.3 m.sup.3). Author Affiliation: (a) Departamento de Engenharia Quimica e de Alimentos, Escola de Engenharia Maua, Instituto Maua de Tecnologia (EEM/IMT), Praca Maua 1, CEP 09.580-900, Sao Caetano do Sul, SP, Brazil (b) Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo (SHS/EESC/USP), Av. Trabalhador Sao-Carlense 400, CEP 13.566-590, Sao Carlos, SP, Brazil (c) Departamento de Engenharia Quimica, Universidade Santa Cecilia, Rua Oswaldo Cruz 266, CEP 11045-907, Santos, SP, Brazil Article History: Received 26 June 2007; Revised 14 April 2008; Accepted 3 August 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2008.05.008 Byline: Tansiphorn Janhom (a), Suraphong Wattanachira (a)(b), Prasert Pavasant (a)(c) Abstract: The wastewater treatment systems from the three local breweries consist of upflow anaerobic sludge blanket (UASB) and activated sludge (AS) connected in series for which the influent and effluent from each treatment step were collected and determined for their dissolved organic matter (DOM) surrogate parameters including dissolved organic carbon (DOC), UV.sub.254 and SUVA.sub.254. The analyses suggested that the influent wastewater contained a high level of aromatic organic content classified as humic substances with high average molecular weight. Organic removal mostly occurred in the UASBs where DOC and UV.sub.254 were reduced by 24-58% and 38-50%, respectively. Spectrofluorometry analysis (fluorescent excitation-emission matrix: FEEM) was reasonably accurate in evaluating DOM reduction during the treatment course. A total of eight fluorescent peaks were detected by the FEEM technique comprising (A) 230nm.sub.Ex/315nm.sub.Em, (B) 275nm.sub.Ex/315nm.sub.Em, (C) 230nm.sub.Ex/365nm.sub.Em, (D) 285nm.sub.Ex/365nm.sub.Em, (E) 290nm.sub.Ex/400nm.sub.Em, (F) 335-355nm.sub.Ex/405-465nm.sub.Em, (G) 255nm.sub.Ex/455nm.sub.Em, and (H) 500nm.sub.Ex/525nm.sub.Em. Peaks 'A and B' and 'C and D' were associated with tyrosine-like, tryptophan-like substances, respectively, whilst each individual peak E, F and G was associated with humic and fulvic acid-like substances. Peaks C, D, F and H were always found in the influent wastewater from all the breweries, whereas the effluents only exhibited Peak F. The origin of Peak H had not been recognized elsewhere and was not identified in this work. This suggested that FEEM could not only be used to monitor the reduction in DOM, but it could also provide details on the organic composition of the wastewater. Author Affiliation: (a) National Center of Excellence for Environmental and Hazardous Waste Management, Chulalongkorn University, Bangkok 10330, Thailand (b) Department of Environmental Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand (c) Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Phyathai Road, Patumwan, Bangkok 10330, Thailand Article History: Received 23 June 2007; Revised 23 April 2008; Accepted 15 May 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.12.015 Byline: Giuseppe Luigi Cirelli (a), Simona Consoli (a), Marcelo Juanico (b) Abstract: The operational parameter MRT%FE, representing the mean residence time of different ages fractions of effluent within a completely mixed reactor, was evaluated and integrated with first order kinetics. The parameter was used to model Escherichia coli concentrations in a municipal wastewater reservoir managed under different operating conditions (continuous and discontinuous). The study was conducted during 2004-2005 in a reservoir receiving effluents from the activated sludge treatment plant of Caltagirone (Eastern Sicily - Italy). The analytical approach is applied to the hydraulic state variables of the system (daily stored volumes, inlet and outlet flows), and the physical-chemical (pH, temperature, EC, TSS, BOD.sub.5, COD) and bacteriological wastewater parameters (E. coli, FC, FS). In order to evaluate the reliability of the proposed approach, predicted E. coli concentrations within the reservoir were compared with measured ones by the correlation coefficient, F-test and Sperman's index. The study included the evaluation of die-off coefficient K.sub.T (d.sup.-1), light extinction coefficient K (m.sup.-1) and their relationships with climatic factors. Results of the study confirm that E. coli removal is related to the fractions of fresh effluent remaining each day within the reservoir with MRT%FE of about 5-8d, significantly lower than the nominal detention time (about 27d). The E. coli die-off coefficient (K.sub.T) was higher during system discontinuous operations and correlated with incident solar radiation and water temperature. Author Affiliation: (a) Department of Agricultural Engineering, University of Catania, Via S. Sofia, 100, 95123 Catania, Italy (b) Juanico-Environmental Consulting Ltd., Moshav Ram-On, M.P. Megido 19205, Israel Article History: Received 8 February 2007; Revised 15 November 2007; Accepted 11 December 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.11.006 Byline: Sarunya Sujaritpong, Vilas Nitivattananon Abstract: As population densities have risen and settlements become increasingly crowded, wastewater effluent volumes have, not unexpectedly, also risen. The adverse impacts of effluent from housing estates (HEs) in suburban areas of Thailand, served by local wastewater management (WWM) systems, are of particular concern. Because of this problem, which reflects the poor performance of WWM systems, it has become increasingly important that the pivotal factors that hinder WWM improvements be identified and effective solutions be proposed and implemented. The goal of the research described in this paper was to determine the critical factors influencing WWM performance at HEs in suburban Bangkok, using multiple regression analysis. Three significant factors encompassing financial, social, institutional and general aspects were identified for each type of WWM system (community centralized and onsite). For the community centralized system, the key factors were house price, type of organization managing the HE, and the attitudes of the organization. For onsite systems, the three factors were total number of house units, direct experience with water pollution and percentage of occupied houses. These findings reflect the importance of having a WWM that employs an integrated approach rather than focusing on specific aspects in isolation from other factors. WWM performance could be improved if significant factors indicating high priority concerns were to be identified and properly applied. Addressing the priority concerns could, consequently, contribute to the development of appropriate environmental management measures, plans, and policies related to HE WWM. Author Affiliation: Urban Environmental Management Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand Article History: Received 18 October 2006; Revised 3 November 2007; Accepted 30 November 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.10.010 Byline: Pablo CaA[+ or -]izares, Ruben Paz, Cristina Saez, Manuel A. Rodrigo Abstract: In the work described here the technical and economic feasibilities of three Advanced Oxidation Processes (AOPs) have been studied: Conductive-Diamond Electrochemical Oxidation (CDEO), Ozonation and Fenton oxidation. The comparison was made by assessing the three technologies with synthetic wastewaters polluted with different types of organic compounds and also with actual wastes (from olive oil mills and from a fine-chemical manufacturing plant). All three technologies were able to treat the wastes, but very different results were obtained in terms of efficiency and mineralization. Only CDEO could achieve complete mineralization of the pollutants for all the wastes. However, the efficiencies were found to depend on the concentration of pollutant (mass transfer control of the oxidation rate). Results obtained in the oxidation with ozone (at pH 12) or by Fenton's reagent were found to depend on the nature of the pollutants, and significant concentrations of oxidation-refractory compounds were usually accumulated during the treatment. Within the discharge limits that all of the technologies can reach, the economic analysis shows that the operating cost of Fenton oxidation is lower than either CDEO or ozonation, although CD\EO can compete satisfactorily with the Fenton process in the treatment of several kinds of wastes. Likewise, the investment cost for the ozonation process seems to be higher than either CDEO or Fenton oxidation, regardless of the pollutant treated. Author Affiliation: Department of Chemical Engineering, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha, Campus Universitario s/n, 13071 Ciudad Real, Spain Article History: Received 23 April 2007; Revised 2 October 2007; Accepted 30 October 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.06.011 Byline: Markus T. Lasut (a), Kathe R. Jensen (b), Ganesh Shivakoti (a) Keywords: Wastewater management; Environmental management; Coastal city; Manado; North Sulawesi; Indonesia Abstract: Manado is the largest and most densely populated coastal city in North Sulawesi Province, Indonesia. The city is facing problems of wastewater discharged from various sources. These problems are driven by high population pressure, increasing economic activity, and low household income, in combination with inadequate organizational structure of government institutions for addressing the wastewater problems as well as for law enforcement. There have been no community initiatives to prevent or mitigate wastewater problems. Therefore, a wastewater management plan is urgently needed to prevent and mitigate pollution caused by discharged wastewater. In this paper we analyze the current situation with respect to environmental state, sources and treatment of wastewater, socio-economic and institutional capacities as well as community awareness. Constraints and potentials are discussed to give recommendations for an integrated wastewater management plan for the city of Manado. Author Affiliation: (a) Integrated Tropical Coastal Zone Management, Asian Institute of Technology, Bangkok, Thailand (b) Zoological Museum, Universitetsparken 15, DK-2100 Copenhagen, Denmark Article History: Received 18 September 2005; Revised 30 May 2007; Accepted 6 June 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.11.013 Byline: Eran Friedler (a), Ori Lahav (a), Hagar Jizhaki (b), Tali Lahav (c) Keywords: Wastewater reuse; Public awareness; Public perception; Urban reuse Abstract: This paper summarizes the findings of a survey (256 participants) conducted to determine the attitude of the Israeli urban public towards various urban water reuse options. Israel is known for its long and successful agricultural water reuse scheme, but to date no large-scale urban reuse projects have been implemented. The survey included 21 reuse options, which were clustered into three reuse categories, namely: low, medium, and high contact levels. Results show that a high proportion of the participants supported medium contact reuse options such as sidewalk landscaping (95%), domestic WC flushing (85%) and firefighting (96%). Higher contact reuse options such as domestic laundry (38%), preserved food (13%), and potable aquifer recharge (11%) found much lesser support. Less than expected support was found for low contact reuse options with 86% for field crop irrigation, 62% for aquifer recharge for agricultural irrigation, and as low as 49% for orchard irrigation. This low support is surprising, since all three options have been practiced on a large scale for over three decades in Israel without any adverse effects to the public. No correlation was found between any biographical characteristic examined (education, gender, income, marital status, having young children, and age) and support for medium contact options. For the medium contact options, the results suggest that perceived financial gain (individual and/or communal) and positive public opinion enhances support, while perceived health effects negatively affects the degree of support. Technology, trust in authorities and awareness of water and environmental issues were found to not have a significant effect on support for medium contact reuse options. Analyzing the four possible reasons for support given by participants who identified themselves as supporters of wastewater reuse revealed that the most important reason for support was 'water saving', followed by 'minimization of importing water from abroad'. These were followed by 'infrastructure cost saving' together with 'environmental improvement'. Author Affiliation: (a) Faculty of Civil and Environmental Engineering, Technion, Haifa, 32000, Israel (b) Faculty of Sociology and Anthropology, Emek Yezreel College, Israel (c) School of Social Work, Hebrew University, Jerusalem, Israel Article History: Received 27 December 2004; Revised 29 September 2005; Accepted 1 November 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.07.011 Byline: Guleda Onkal Engin (a), Ibrahim Demir (b) Abstract: Wastewater collection and treatment is quite important for sustainable management. It would be uneconomical and impractical to provide sewer systems and separate wastewater treatment plants (WWTP) for small communities. The decision process in wastewater planning is rather important in terms of comparing the alternatives considered. The two important points in the management of wastewater at rural areas not connected to a sewer system are to develop an optimized operation strategy and to make sure that the complete system is environmentally and economically sustainable. In some regions, package treatment could be an alternative solution. However, in cases where there is an existing large WWTP, a cluster system, where sewage generated by small communities could be transported via conveyors to a centralized WWTP, could be employed. In this study, the wastewater treatment and disposal problems in small communities were addressed and an alternative wastewater handling scenario was proposed. Additionally, three wastewater handling scenarios were compared. As a case study, Gebze villages were selected. Author Affiliation: (a) Gebze Institute of Technology, Faculty of Engineering, Department of Environmental Engineering, Gebze, 41400, Kocaeli, Turkey (b) Environmental Informatics and Control Program, Warnell School of Forest Resources, University of Georgia, Athens, GA 30602, USA Article History: Received 7 September 2004; Revised 21 July 2005; Accepted 21 July 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.05.008 Byline: Joselito M. Arocena (a), Sanjay K. Nepal (b), Michael Rutherford (c) Abstract: Balancing recreation and conservation is an important issue in Canada's parks and protected areas. Increased levels of visitation to parks, especially to backcountry areas, create undue pressure on natural resources, resulting in a variety of ecological impacts. This paper illustrates the issue of visitor-induced changes on the chemical composition of soils in Mt Robson Provincial Park, British Columbia. Soil samples were collected from dish wash stations and fire pits (disturbed sites) at seven campgrounds located along two popular backcountry trails, and were compared to samples obtained from adjacent undisturbed control sites. Analysis of soil samples suggest that the lower amounts of aluminum, potassium, magnesium and sodium in many of the 'disturbed' samples can be related to intense leaching in dish wash stations, and can be attributed to frequent disposal of waste water from washing and cooking activities. Soils in wash stations generally had higher phosphorus, copper and zinc contents as compared to controls. Soils in fire pits were elevated in copper, relative to controls. Results of this study support park regulations that waste water disposal and camp fires be restricted to designated areas. Informing the public of scientific studies helps them understand the consequences of their activities; this may help persuade them to observe park rules and regulations. Author Affiliation: (a) Ecosystem Science and Management Program and Canada Research Chair -- Soil and Environmental Sciences, University of Northern British Columbia, Prince George, BC, Canada V2N 4Z9 (b) Department of Recreation, Park and Tourism Sciences, Texas A&M University, College Station, TX 77843-2261, USA (c) Environmental Science and Engineering Programs, University of Northern British Columbia (UNBC), 3333 University Way, Prince George, BC, Canada V2N 4Z9 Article History: Received 5 June 2004; Accepted 18 May 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.03.010 Byline: Yasemin Bulut, Zubeyde Baysal Abstract: The adsorption of Pb(II) ions from aqueous solutions on wheat bran (WB) has been investigated as a function of initial concentration, adsorbent dose, adsorbent particle size, agitation speed, temperature, contact time and pH of solution. The equilibrium process was described well by the Langmuir isotherm model with maximum sorption capacities of 69.0, 80.7 and 87.0mgg.sup.-1 of Pb(II) on wheat bran at 20, 40 and 60[degrees]C, respectively. Thermodynamic parameters, i.e. [DELTA]G.sup.0, [DELTA]H.sup.0 and [DELTA]S.sup.0 have also been calculated for the system and the sorption process was found to be endothermic. Good correlation coefficients were obtained for the pseudo second-order kinetic model. The metal ion could be stripped by addition of 0.5M HCl, making the adsorbent regeneration and its reutilization possible. Author Affiliation: Department of Chemistry, Faculty of Science-Art, Dicle University, Diyarbakir, Turkey Article History: Received 26 January 2004; Revised 12 February 2005; Accepted 30 March 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.03.012 Byline: Preeti C. Sangave, Aniruddha B. Pandit Abstract: A combined treatment technique consisting of enzymatic hydrolysis, followed by aerobic biological oxidation was investigated for the treatment of alcohol distillery spent wash. The enzyme cellulase was used for the pretreatment step with an intention of transforming the complex and large pollutant molecules into simpler biologically assimilable smaller molecules. Batch experiments were performed in order to analyze the influence of various parameters like pretreatment time, enzyme concentration and pH during the pretreatment step on the subsequent aerobic oxidation kinetics. The rate of aerobic oxidation was enhanced by 2.3 fold for the pretreated sample as compared to the untreated sample when the pH during the pretreatment step was maintained at a value of 4.8. Similarly, a two fold increase in the aerobic oxidation rate was found when the effluent was pretreated with the enzyme, without any pH control (i.e. effluent pH of 3,8). The study indicated that the enzymatic pretreatment of the effluent could be one of the successful pretreatments which can lead to enhancement of the rate of the subsequent aerobic oxidation. Author Affiliation: Chemical Engineering Division, University Institute of Chemical Technology, Matunga, Mumbai 400019, India Article History: Received 12 May 2004; Revised 3 March 2005; Accepted 21 March 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.02.005 Byline: Wen-Cheng Liu (a), Shin-Yi Liu (b), Ming-Hsi Hsu (b), Albert Y. Kuo (c) Abstract: The Hsintien Stream is one of the major branches of the Danshuei River system, which runs through the metropolitan capital city of Taipei, Taiwan and receives a large amount of wastewater. The dissolved oxygen concentration is generally low in the tidal portion of the Hsintien Stream. Hypoxia/anoxia occurs often, particularly during the low-flow period when the Feitsui Reservoir, Chingtan Dam and Chihtan Dam impound the freshwater for municipal water supply. Fish kills happen from time to time. This paper describes the application of a numerical hydrodynamic and water quality model to the Danshuei River system, with special attention to the tidal portion of the Hsintien Stream. The model is recalibrated with the prototype conditions of the year 2000. The hydrodynamic portion of the model is recalibrated with measured surface elevation and velocity at various stations in the river system. The water quality portion of the model is recalibrated with respect to the field data provided by Taiwan EPA. The input data of point and nonpoint sources are also estimated. The model simulates the concentrations of various forms of nutrients, CBOD and dissolved oxygen. A series of sensitivity runs was conducted to investigate the effects of point source loadings and river flow on the DO level in the river. It is demonstrated that the augmentation of river flow has as much effect on raising DO level as the reduction of point source loadings. The completion of the Taipei sewer project is expected to reduce the point source loadings by at least 75%. Under these reduced loadings, if the daily instream flow is maintained above the monthly Q.sub.75 flow throughout the year, the minimum DO concentration in the river would not fall below 1mg/L, which is the suffocation level for most fish species in the Hsintien Stream. (Q.sub.75 is the flow which is equaled or exceeded 75% of the days in the month.) The Feitsui Reservoir, Chingtan Dam and Chihtan Dam may impound water during the high flow periods and release freshwater to maintain the flow at the Q.sub.75 value in the Hsintien Stream during the drought periods. Author Affiliation: (a) Department of Civil and Disaster Prevention Engineering, National United University, Miao-Li 360, Taiwan, ROC (b) Department of Bioenvironmental Systems Engineering and Hydrotech Research Institute, National Taiwan University, Taipei 10617, Taiwan, ROC (c) National Center for Ocean Research, National Taiwan University, Taipei 10617, Taiwan, ROC Article History: Received 4 April 2004; Accepted 15 February 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2004.11.025 Byline: Xinhao Wang (a), Mike Homer (b), Scott D. Dyer (b), Charlotte White-Hull (b), Changming Du (c) Abstract: Scientists often use mathematical models to assess river water quality. However, the application of the models in environmental management and risk assessment is quite limited because of the difficulty of preparing input data and interpreting model output. This paper presents a study that links ArcIMS, a Web-based Geographic Information System (GIS) software to ROUT, a national and regional scale river model which evolved from the US Environmental Protection Agency's Water Use Improvement and Impairment Model, to create a WWW-GIS-based river simulation model called GIS-ROUT. GIS-ROUT is used to predict chemical concentrations in perennially flowing rivers throughout the continental United States that receive discharges from more than 10,000 publicly owned wastewater treatment plants (WWTPs). The WWTP chemical loadings are calculated from per capita per day disposal of product ingredients and the population served by each plant. Each WWTP, containing data on treatment type and influent and effluent flows, is spatially associated with a specific receiving river segment. Based on user defined treatment-type removal rates for a particular chemical, an effluent concentration for each WWTP is calculated and used as input to the river model. Over 360,000km of rivers are modeled, incorporating dilution and first order loss of the chemical in each river segment. The integration of spatial data, GIS, the WWW, and modeling in GIS-ROUT makes it possible to organize and analyze data spatially, and view results on interactive maps as well as tables and distribution charts. The integration allows scientists and managers in different locations to coordinate and share their estimations for environmental exposure and risk assessments. Author Affiliation: (a) School of Planning, University of Cincinnati, College of DAAP, 346 Clifton Court, 6210 DAAP, Cincinnati, OH 45221-0016, USA (b) Miami Valley Laboratories, The Procter & Gamble Co., P.O. Box 538707, Cincinnati, OH 45253, USA (c) Geo-Science and Planning Solutions, 2185 Mainsail Dr., Marietta, GA 30062, USA Article History: Received 27 January 2004; Revised 1 November 2004; Accepted 8 November 2004

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2004.10.004 Byline: Dae In Lee (a), Chung Kil Park (a), Hyeon Seo Cho (b) Abstract: This study estimated the appropriate pollutant load reduction from point sources in Kwangyang Bay, Korea, using an eco-hydrodynamic model. The total chemical oxygen demand (COD), nitrogen (TN), and phosphorus (TP) loads from rivers and ditches that provide input to the bay were approximately 2.8x10.sup.4, 2.5x10.sup.4, and 5.9x10.sup.2 kgday.sup.-1, respectively. Wastewater discharge from industrial complexes was the greatest contributor to pollutant loads in the inner part of the bay. COD values in the inner part of the bay were greater than 3.0mgl.sup.-1, and exceeded Korean seawater quality grade III limits. A residual current was simulated, using a hydrodynamic model, to have a slightly complicated pattern in the inner part of the bay, ranging from 0.001 to 8cms.sup.-1. In the outer part of the bay, the simulated current flowed out to the South Sea with a southward flow at a maximum of 15cms.sup.-1. The results of the ecological model simulation of COD levels showed high concentrations, exceeding 4mgl.sup.-1, in the southwest of the Myodo, an area of wastewater discharge, and lower levels, approaching less than 1mgl.sup.-1, closer to the outer part of the bay. Engineering countermeasures to reduce the organic and inorganic material loads from point sources by more than 45% were required to keep the COD levels below 2mgl.sup.-1. Author Affiliation: (a) Division of Environmental System Engineering, Pukyong National University, Busan 608-737, South Korea (b) Division of Ocean System, Yosu National University, Yeosu, Jeonnam 550-749, South Korea Article History: Received 21 May 2003; Revised 18 October 2004; Accepted 21 October 2004