Personal Research Database

Full Text: W\Wat Sci Tec34, 295.pdf

Abstract: The seasonal change of microbial population and activities in an existing building wastewater reuse system using membrane separation activated sludge process (MSAS) were investigated, and they were also compared with those in a municipal wastewater treatment plant using conventional activated sludge (CAS) process. The operating conditions of MSAS process, such as sludge retention time, biomass concentration, the ratio of food to microorganism () and so on, are much different from CAS process. Acridine orange direct count (AODC), plate count of heterotrophic bacteria (HPC), MPN of ammonia oxidizing bacteria (MPNa) and microfauna were measured. In the MSAS process, the AODC and MPNa/HPC were high, but the HPC/AODC was low. This means that the MSAS process tended to maintain a high ratio of ammonia oxidizing bacteria and also tended to keep dead cells. The microfauna in the MSAS process was unstable and changed a lot seasonally, but it wouldn’t affect the treatment efficiency. Moreover, the specific activities of nitrification, denitrification and organic removal fluctuated largely and seasonally, and were lower than those in the CAS process. However, their volumetric activities were higher than those in the CAS process because the MSAS process could maintain very high biomass concentration. Dehydrogenase activity, ATP content and oxygen utilization rate were measured to estimate the bacterial activities and viability. The OUR and ATP has different relationship in the both processes. Polysaccharides were also determined as metabolic products.

Keywords: Membrane Separation, Activated Sludge, Bacterial Population, Bacterial Activity, Microfauna

Lawrence, A. and Poulter, C. (1996), The potential role of the estuarine amphipod Gammarus duebeni in sub-lethal ecotoxicology testing. Water Science and Technology, 34 (7-8), 93-100.

Full Text: W\Wat Sci Tec34, 93.pdf

Abstract: The aim of this study was to assess the suitability of Gammarus duebeni as an indicator of estuarine pollution. This involved the development of sub-lethal pollution bioassays monitoring respiration rate, swimming efficinecy and precopula pairing; assessment of the sensitivity of the assays to copper pollution and comparison of the suitability of the assays. Significant impairment of respiration rate, as measured by changes in pleopod beat, was determined at a copper concentration of 600 µgl^-1. Significant impairment to swimming ability was determined after exposure to copper pollution at a concentration of 600 µgl^-1 and precopula pairing was significantly reduced at a concentration of 600 µgl^-1. of the assays, swimming efficiency and pleopod beat frequency appear to offer the most potential for further development. The lower limit of sensitivity of the bioassays developed in this study is yet to be determined. However, the levels of copper shown to induce an effect can be experienced in the natural environment. The study has shown that Gammarus duebeni can be used in sub-lethal pollution assays, at relatively high Cu concentrations and indicates that it is potentially a useful species with which to assess estuarine water and sediment pollution.

Tkalitch, P.V., Chen, W. and Tay, J.H. (1996), Modeling of heavy metals in a reservoir with diffusive bottom layer. Water Science and Technology, 34 (7-8), 117-123.

Full Text: W\Wat Sci Tec34, 117.pdf

Abstract: A model of heavy metal kinetics in the well mixed reservoir with respect to vertical diffusion in the active bottom layer is presented. The model incorporates the mechanisms of a heavy metal reaction process between ‘overlying water-suspended sediments-interstitial water-bottom sediment’. Application of longterm modeling is provided to simulate the self-cleaning abilities of the Kranji Reservoir. The adsorption rate of Zn on bottom sediments was determined by a modified batch test. The analytical results demonstrate the high retention and concentration of Zn in the interstitial water, which indicates the importance of including the interstitial water quality in the assessment of potential ecological effects. The numerical simulations show the influence of the bottom diffusive layer on Zn long-term dynamics in the aquatic system. Copyright (C) 1996 IAWQ.

Keywords: Bottom Diffusive Layer, Distribution and Diffusion Coefficients, Interstitial Water, Kinetic Model, Sediments, Tropical Reservoir, Zinc

Matheickal, J.T. and Yu, Q. (1996), Biosorption of lead from aqueous solutions by marine algae Ecklonia radiata. Water Science and Technology, 34 (9), 1-7.

Full Text: W\Wat Sci Tec34, 1.pdf

Abstract: Experimental studies showed that brown marine algae, Ecklonia radiata, can be used for the development of an efficient biosorbent material for heavy metal removal from wastewater. E. radiata exhibited high uptake capacities for lead, cadmium and copper. In particular, lead sorption was very marked. The equilibrium data fitted well to the Langmuir isotherm model. Within a pH range of 4.5 to 5.5, the uptake capacity of E. radiata for lead is 1.36 mM/g (282 mg/g), which is much higher than those of powdered activated carbon and natural zeolite. Studies indicated that sorption of lead increases as pH increases and reaches a plateau at pH 5. The lead uptake process was rapid, with 60% of me sorption completed within 10 minutes. Presence of light metal ions in solution did not affect lead sorption significantly. Breakthrough curves of fixed bed operations were obtained to illustrate the process of lead removal in a continuous flow system.

Keywords: Heavy-Metals, Accumulation, Biosorbents, Recovery, Removal, Uranium, Biosorbent, Biosorption, Ecklonia Radiata, Heavy Metal Removal, Lead Removal, Marine Algae, Wastewater

Booker, N.A., Cooney, E.L. and Priestly, A.J. (1996), Ammonia removal from sewage using natural Australian zeolite. Water Science and Technology, 34 (9), 17-24.

Full Text: W\Wat Sci Tec34, 17.pdf

Abstract: A rapid adsorption process, which utilises the ammonium ion selectivity of a natural Australian zeolite, is being developed for removal of ammonia from sewage. The study reported in this paper claims not to have invented nor discovered this technique of ammonia removal from wastewater, but aims to realise the value of this natural Australian resource as an efficient alternative to existing treatment processes. An understanding of the equilibrium and kinetic behaviour of this material provided insight into its expected capacity as an adsorption media. Favourable results led to pilot scale trials, which revealed excellent performance of the zeolite under continuous column operation. The zeolite adsorption process has proved effective, at pilot scale, in reducing ammonium ions in sewage from concentrations ranging from 25 to 50 mgNH₄-N/L down to levels below 1 mgNH₄-N/L. Under optimised operating conditions, the adsorption capacity of the zeolite for this range of influent ammonium concentrations was about 4.5 mgNH₄-N/g. The rate of treatment by the pilot zeolite column makes it ideally suited as a retrofit to high rate secondary sewage treatment processes, for removal of the soluble ammonium component.

Keywords: Ammonia, Ammonium, Nutrient Removal, Sewage Treatment, Sirofloc, Zeolite

Kongsricharoern, N. and Polprasert, C. (1996), Chromium removal by a bipolar electrochemical precipitation process. Water Science and Technology, 34 (9), 109-116.

Full Text: W\Wat Sci Tec34, 109.pdf

Abstract: This research was conducted in laboratory to investigate an alternative for Cr removal from an electroplating wastewater using the electro-chemical precipitation (ECP) process. The ECP unit, operated in the bipolar mode, had six steel plates including the anode and cathode and was supplied with DC power, The electroplating wastewater used in the experiments contained Cr concentrations in the range of 570-2100 mg/l. The Cr removal efficiencies in the bipolar ECP units were higher than 99% and the Cr concentrations in the treated effluent were less than 0.5 mg/l. The acceptable conditions of the bipolar ECP unit treating the electroplating wastewater were found to be: I-1.0 amp (or i-6.70 amp/m²) and initial pH (pH_i) of 4.5. At these acceptable conditions, the electric power and steel electrode plate consumptions were 20.0 kWh/m³ and 1.1-2.8 kg-Fe/kg Cr removed, respectively, X-ray fluorescence and X-ray diffractometric analysis performed on the precipitated sludge revealed the main compounds to be maghemite (Fe₂O₃) and chromite. The percent Fe₂O₃ and FeCr₂O₄ contents of the dried ECP sludge were 68% and 25%, respectively. From the mass balance analysis, the percent of Cr removal by precipitation in the ECP unit and adsorption on the ECP sludge were 85.1 and 14.8%, respectively.

Keywords: Water, Electroplating Wastewater, Chromium, Electrochemical Precipitation, Heavy Metal Removal, Sludge

Brasquet, C., Roussy, J., Subrenat, E. and Le Cloirec, P. (1996), Adsorption of micropollutants onto fibrous activated carbon: Association of ultrafiltration and fibers. Water Science and Technology, 34 (9), 215-222.

Full Text: W\Wat Sci Tec34, 215.pdf

Abstract: The adsorption of polluted solutions is performed by different kinds of activated carbon: grains, powder and fibers (cloth or felt). The adsorption is carried out in a batch reactor. Classic models are applied and kinetic constants are calculated. Results showed that the performance of fiber activated carbon (FAC) is significantly higher than that of granular activated carbon (GAG). Moreover, FAC’s adsorption capacities of phenol are greater than GAC’s. Therefore the application of FAC adsorbers may lead to smaller adsorption reactors. The breakthrough curves obtained with FAC adsorbers are particularly steep, suggesting a smaller mass transfer resistance than GAG. The adsorption zone in the FAC bed is about 3.4 mm and is not dependent on the flow rate within the range 0.67-2.07 mh^-1. The selectivity of the FAC between different size of soluble molecules is shown. Then, an Ultrafiltration (UF) membrane is coupled with FAC to remove successively macromolecules (humic substances) and phenols present together in an aqueous solution. This new and original approach to a water treatment compact process successfully put to use. Industrial developments are put forward.

Keywords: Adsorption, Fibrous Activated Carbon, Humic Substances, Phenol, Organic Matter, Ultrafiltration, Water Treatment, Removal, PAC

? Liu, J.X., Wang, B.Z., Li, W.G., Jin, C.J., Cao, X.D. and Wang, L. (1996), Removal of nitrogen from coal gasification and coke plant wastewaters in A/O submerged biofilm-activated sludge (SBF-AS) hybrid system. Water Science and Technology, 34 (10), 17-24.

Full Text: 1996\Wat Sci Tec34, 17.pdf

Abstract: Experimental research involving both laboratory and full-scale studies has been carried out to evaluate the nitrification-denitrification process carried out in a submerged biofilm (in anoxic zone)-activated sludge (in oxic zone) (SBF-AS) hybrid system for nitrogen removal from coal gasification and coke plant wastewaters. The anoxic reactor in the system was packed with fibrous carriers fixed on plastic plates of circular form for the attached growth of submerged biofilm with facultative denitrifying bacteria as dominant species to carry out denitrification, and the activated sludge process was used in the aerobic reactor for nitrification. As the denitrifying and nitrifying bacteria live under anoxic and aerobic conditions respectively in the hybrid system, the process was tested under the conditions of high organic and ammonia loading rates and short hydraulic retention time(HRT). The experimental results show that ammonia nitrogen, NH₃-N removal is between 94% and 99.9% and COD removal between 80% and 95%. Copyright (C) 1996 IAWQ.

Keywords: A/O Submerged Biofilm-Activated Sludge Hybrid System, Activated Sludge, Ammonia, Ammonia-Nitrogen, Anoxic, Biological Removal of Nitrogen, Coal Gasification Wastewater, Cod Removal, Coke Plant, Coke Plant Wastewater, Denitrification, NH₃-N Removal, Nitrification, Nitrification-Denitrification, Oxic

Mittal, A.K. and Gupta, S.K. (1996), Biosorption of cationic dyes by dead macro fungus Fomitopsis carnes: Batch studies. Water Science and Technology, 34 (10), 81-87.

Full Text: W\Wat Sci Tec34, 81.pdf

Abstract: Application of dead macrofungus, Fomotopsis carnea for the sorption of three cationic dyes viz., Orlamar Red BC (ORBG), Orlamar Blue G (OBG) and Orlamar Red GTL (ORGTL) has been investigated. This study mainly focuses on the effect of various sorption kinetic parameters for the uptake of ORBG. Fomitopsis carnea shows excellent sorption potential for all the dyes studied. Saturation capacities for ORBG, OBG and ORGTL are 503.1, 545.2 and 643.9 mgg^-1 respectively. Biosorption in the batch adsorber can be described by first-order reaction kinetics. Sorption decreases with decrease in pH.

Hu, T.L. (1996), Removal of reactive dyes from aqueous solution by different bacterial genera. Water Science and Technology, 34 (10), 89-95.

Full Text: W\Wat Sci Tec34, 89.pdf

Abstract: The use of biomass for the removal of reactive dyes from an aqueous solution with different bacterial genera has been investigated. Three Gram-negative bacteria: Aeromonas sp., P. luteola and E. coli and two Gram-positive bacteria: B. subtilis and S. aureus and a mixed biomass of activated sludge are the tested biosorbents. Dead cells of Gram-negative bacteria have a higher specific adsorption capacity than the living cells. The dye removal is in the order of Aeromonoas sp. > P. luteola > E. coli. The adsorption equilibrium can be reached within one hour. Due to the positively charged cells at acidic pH, the removal of reactive dyes increases with decreasing pH. Evaluating the adsorption parameters, bacterial biomass exhibits stable adsorption characteristics, which makes it a suitable adsorbent for different dye compounds.

Keywords: Hazardous Organic Pollutants, Fly-Ash, Adsorption, Biosorption, Sorption, Biomass, Sludge, Azo, Reactive Dyes, Adsorption, Biomass, Specific Adsorption Capacity

Jansson-Charrier, M., Guibal, E., Roussy, J., Surjous, R. and Le Cloirec, P. (1996), Dynamic removal of uranium by chitosan: Influence of operating parameters. Water Science and Technology, 34 (10), 169-177.

Full Text: W\Wat Sci Tec34, 169.pdf

Abstract: New wastewater treatments involving biosorption processes are being developed This work focuses on the dynamic removal of uranium using chitosan in fixed-bed reactors and investigates the main operating parameters: particle size, column size, flow velocity and metal ion concentration. The results confirm the predominant effect of diffusion on the control rate. The optimization of the process should take into account both sorption performances and hydrodynamic behaviour. The process is successfully applied to the treatment of leachates at an abandoned mine site. This study shows that chitosan is an effective sorbent for the treatment and recovery of uranium from dilute effluents.

Keywords: Glutamate Glucan, Uranyl Ions, Sorption, Derivatives, Performances, Biosorption, Equilibrium, Adsorption, Polymers, Waters, Adsorption, Chitosan, Column Size Effect, Concentration Effect, Desorption, Pilot Scale Application, Fixed Bed Reactor, Flow Velocity Effect, Particle Size Effect, Uranyl Ions

Tünay, O., Kabdasli, I., Eremektar, G. and Orhon, D. (1996), Color removal from textile wastewaters. Water Science and Technology, 34 (11), 9-16.

Full Text: W\Wat Sci Tec34, 9.pdf

Abstract: The requirement of color removal has promoted the research in this field. However, there is still a lack of understanding of colour problems. In this paper a literature review is made to assess the information on color removal and need for systematic evaluation of the results is emphasized. Experimental studies are conducted on the textile dyeing wastewaters applying chemical precipitation, chemical oxidation, adsorption and their combination. Results of the study are evaluated and discussed within the context of a systematic approach.

Keywords: Industry Wastewaters, Adsorption, Chemical Oxidation, Chemical Precipitation, Color Removal, Textile Wastewater

Baes, A.U., Umali, S.J.P. and Mercado, R.L. (1996), Ion exchange and adsorption of some heavy metals in a modified coconut coir cation exchanger. Water Science and Technology, 34 (11), 193-200.

Full Text: W\Wat Sci Tec34, 193.pdf

Abstract: Potentiometric titration experiments were carried out to determine the relative ability of sodium and different heavy metal cations in replacing protons from ionogenic sites of a modified coconut coir cation exchanger. The relative preference for the cations follow the sequence: Na << Ca(II) < Mn(II) < Ni(II) < Cu(II) < Pb(II). This preferential series was confirmed by determining the concentrations of the divalent cations and sodium which were adsorbed by the materiAl-During the titration process. Adsorption isotherms at pH 4 and pH 6 were obtained to determine the Langmuir adsorption constants for the heavy metal cations. The adsorbent material adsorbed high amounts of Pb(II), Cu(II) and Ni(II) (in decreasing order) from solutions whose concentrations were comparable to those of wastewaters. Our results show that the modified coconut coir cation exchanger has good potential as an adsorbent of heavy metals in industrial wastewaters.

Keywords: Adsorption, Cation Exchanger, Heavy Metals, Modified Coconut Coir, Potentiometric Titration

Kueh, C.S.W. and Chui, H.K. (1996), Integrated catchment management of Deep Bay, Hong Kong. Water Science and Technology, 34 (12), 1-8.

Full Text: W\Wat Sci Tec34, 1-8.pdf

Abstract: Deep Bay contains one of the most important wetlands in southern China It is located at the border of Hong Kong and the Shenzhen Special Economic Zone (SEZ). Over 50,000 birds rely on this wetland as a breeding, feeding, resting and refuelling station in winter. The Deep Bay catchment is also one of Asia’s fastest developing areas. Its population has doubled since 1984. The rapid population increase and economic development have exerted considerable pressure on the wetland environment. Efforts have been made to reduce the pollution loads by both the Hong Kong and Shenzhen Governments to protect this ecologically important wetland. Through the implementation of a series of environmental programmes, including: sewerage master plans, the livestock waste control scheme and enforcement of the Water Pollution Control Ordinance, the pollution loads arising from Hong Kong decreased from 125,000 to 45,000 kgBOD₅/day between 1988 and 1994 and are expected to further reduce to around 3,000 kgBOD₅/day by the year 2000. To protect the wetland community while promoting sustainable development in the catchment, Hong Kong initiated a study in 1995 to develop a mathematical model for the bay and a water quality management strategy for the future.

Burrows, R. (1996), A sewage disposal strategy for the Isle of Man. Water Science and Technology, 34 (12), 119-126.

Full Text: W\Wat Sci Tec34, 119.pdf

Abstract: The Isle of Man sits in the middle of the Irish Sea, surrounded by the United Kingdom (UK) coasts of England, Scotland, Wales and Northern Ireland. It is, however, independently governed by its own Parliament, Tynwald and is not part of the European Union (formerly the European Community, EC). A radical scheme for the integrated sewerage provision of the whole of the Island, of population approximately 65,000, involving centralised treatment and re-use of sewage sludges, has been accepted in principle. The policy adopted, as realised in the so-called ‘IRIS’ scheme, goes beyond the level of provision called for by the recent EC Directive on Urban Wastewater Treatment, yet the threat posed by the Isle of Man to the waters of the Irish Sea is negligible in comparison to the major inputs from its more populous neighbours. The geographic separation of the Island from the major pollution inputs from the British and Irish mainlands should ensure unobstructed assimilation of its releases by the marine environment. In many instances the coastal communities of the island, through their small size, would be without the statutory responsibility for land based treatment provision, even if bound by the EC legislation. This article, based on evidence presented to Public Inquiry on a first phase of the scheme’s implementation, expresses the view that the strategy for future sewerage provision should be re-evaluated in the light of the flexibilities in implementation which would be afforded to the Isle of Man under the EC legislation. More fundamentally, however, it is suggested that the ‘marine treatment’ option using long-sea outfalls should be incorporated in the range of scheme options to be evaluated against achievement of a ‘best environmental solution’. The argument developed herein draws extensively on the background leading to the UK Water Industry’s reluctant adoption of the EC legislation. These circumstances are considered worthy of report in their own right and the Isle of Man provides an ideal case study.

Keywords: Sewage Disposal, Outfalls, Marine Treatment, Environmental Impacts, Legislation, Harmonisation

? Bally, D., Asano, T., Bhamidimarri, R., Chin, K.K., Grabow, W.O.K., Hall, E.R., Ohgaki, S., Orhon, D., Milburn, A., Purdon, C.D. and Nagle, P.T. (1996), Water quality international 96.4. environmental contaminants health related water microbiology coastal pollution and eutrophication environmental restoration, groundwater contamination and management solid waste disposal selected proceedings of the 18th biennial conference of the international association on water quality, held in Singapore, 23-28 June 1996 preface. Water Science and Technology, 34, R9-R9.

Holmes, P.R. (1996), Measuring success in water pollution control. Water Science and Technology, 34 (12), 155-164.

Full Text: W\Wat Sci Tec34, 155.pdf

Abstract: Ambient water quality is much used to show progress in water pollution control. The state of the environment is not easy to measure reliably and may be subject to very many factors other than the impact of polluting discharges and those who seek to control them. Even measured trends in water quality do not prove that the pollution control activity is being managed to the best standards of efficiency and effectiveness. So managers may have great difficulty in measuring their success or in correctly attributing change in the environment to their action. On the other hand, owners of pollution control systems, both public and private, make little allowance for scientific scruples in their demands for objective measures of effectiveness. The paper examines the theory behind these contradictions and uses the recent development of performance indicators for environmental management in Hong Kong to consider how theory and practice differ. It concludes that effectiveness is relative, but pollution control managers can help themselves if they integrate into their organizations a constant alertness to fundamental goals.

Notes: highly cited

? Brix, H. (1997), Do macrophytes play a role in constructed treatment wetlands? Water Science and Technology, 35 (5), 11-17.

Full Text: 1997\Wat Sci Tec35, 11.pdf

Abstract: The larger aquatic plants growing in wetlands are usually called macrophytes. These include aquatic vascular plants, aquatic mosses and some larger algae. The presence or absence of aquatic macrophytes is one of the characteristics used to define wetlands, and as such macrophytes are an indispensable component of these ecosystems. As the most important removal processes in constructed treatment wetlands are based on physical and microbial processes, the role of the macrophytes in these has been questioned. This paper summarizes how macrophytes influence the treatment processes in wetlands.

The most important functions of the macrophytes in relation to the treatment of wastewater are the physical effects the presence of the plants gives rise to. The macrophytes stabilise the surface of the beds, provide good conditions for physical filtration, prevent vertical flow systems from clogging, insulate the surface against frost during winter, and provide a huge surface area for attached microbial growth. Contrary to earlier belief, the growth of macrophytes does not increase the hydraulic conductivity of the substrate in soil-based subsurface flow constructed wetlands. The metabolism of the macrophytes affects the treatment processes to different extents depending on the type of the constructed wetland. Plant uptake of nutrients is only of quantitative importance in low-loaded systems (surface flow systems). Macrophyte mediated transfer of oxygen to the rhizosphere by leakage from roots increases aerobic degradation of organic matter and nitrification. The macrophytes have additional site-specific values by providing habitat for wildlife and making wastewater treatment systems aesthetically pleasing. (C) 1997 IAWQ.

Keywords: Hydraulic Conductivity, Biochemical Oxygen Demand, Rhizosphere, Oxygen Transport, Root Oxygen Release, Aeration, Nutrient Uptake, Potamogeton-Perfoliatus L, Trin Ex Steudel, Phragmites-Australis, Oxygen Release, Aquatic Macrophytes, Flood Tolerance, Water-Flow, Roots, Plants, Soil

Wittgren, H.B. and Mæhlum, T. (1997), Wastewater treatment wetlands in cold climates. Water Science and Technology,