Boonthanon, S, Hwan, L, Vigneswaran, S, Aim, R & More, JC 1991, 'Application of pulsating cleaning technique in crossflow microfiltration', Filtration & Separation, vol. 28, no. 3, pp. 199-201.
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Crossflow microfiltration (CFMF), is a pressure driven membrane process allowing better permeate flux by shearing action of flow. It can remove most of the impurities found In water and wastewater. But there are still major problems to be solved caused by fouling, deposition and internal clogging, which reduce the efficiency of separation. The pulsation cleaning technique is one of the methods used to avoid or minimise these drawbacks. Laboratory scale microfiltration using a clay suspension was carried out to study the effect of the pulsation cleaning technique on overall CFMF performance at various pulsation times of flux. It was found that the higher permeate flux was obtained when the operation of pulsation was more frequent. Also the study performed showed that this technique improved the permeate flux by 80%. © 1991.
Manandhar, UK & Vigneswaran, S 1991, 'Effect of media size gradation and varying influent concentration in deep-bed filtration: Mathematical models and experiments', Separations Technology, vol. 1, no. 4, pp. 178-183.
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A new model for deep-bed filtration that considers the presence of medium size gradations and the variation of influent concentration with time is proposed. In formulating the model, the rate of filtration is assumed to be either enhanced or retarded by the deposited particles, and the increase in the headloss necessary to maintain a given flow is estimated from the Kozeny equation. Simulated filter performance based on the model was found to agree with pilot plant data on the filtration of clarified effluent from a water treatment plant.
Vigneswaran, S & Chang, J-S 1991, 'Effect of media pore size distribution on deep-bed filtration', Separations Technology, vol. 1, no. 5, pp. 259-266.
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One important parameter of filtration, the media pore size distribution, has not been explicitly considered in modeling deep-bed filtration models by previous investigators. In this study, we propose, based on the hypothesis of O'Melia-Ali and the use of the effective medium approximation theory, a new transient-state model and examine the effect of the media pore size distribution on filter performance. From the simulation results based on six different pore size distribution functions, it is clear that the pore size distribution plays an important role in determining the removal efficiency as well as headloss development
Vigneswaran, S, Casiano, VL & Polprasert, C 1991, 'Application of Coarse-Media Slow Sand Filtration in Aquaculture', Water Science and Technology, vol. 23, no. 10-12, pp. 1817-1824.
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Laboratory experiments were carried out with pilot-scale experimental unit of Coarse Media Slow Sand Filter (CMSSF). A 2.7 m high filter column with a diameter of 0.56 m was operated with the filter media size of 1-2 mm and media depth of 1.0 m at filtration rates of 0.5 and 0.2 m3/m2h. This was connected to a circular concrete fish tank with a diameter of 1.16 m. The performance of CMSSF was compared with the 1.5 m × 1.0 m × 1.0 m Biological Filter (BF) operated at a filtration rate of 1.92 m3/m2h which was connected to 8 fish tanks. Experimental results showed that CMSSF has comparatively higher removal efficiency than BF for turbidity, total phosphorous, nitrogen and organic carbon. This study is an initial attempt to introduce CMSSF as a treatment unit in a recirculating aquaculture system which would be an economical solution to improve the water quality and production in aquaculture.
Zhou, JL & Banks, CJ 1991, 'Removal of humic acid fractions by Rhizopus arrhizus: Uptake and kinetic studies', Environmental Technology, vol. 12, no. 10, pp. 859-869.
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Zhou, JL & Banks, CJ 1991, 'The adsorption of humic acid fractions by fungal biomass', Environmental Technology, vol. 12, no. 6, pp. 519-529.
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Zhou, JL & Kiff, RJ 1991, 'The uptake of copper from aqueous solution by immobilized fungal biomass', Journal of Chemical Technology & Biotechnology, vol. 52, no. 3, pp. 317-330.
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AbstractThe removal of cupric ions from aqueous solution by a biosorption column in which the Rhizopus arrhizus fungal biomass was immobilized in reticulated foam biomass support particles was studied. Solution pH was found to be crucial to copper uptake, with the optimum range being 6·7–7·0. The removal efficiency was usually higher at low influent copper concentration and long residence time. The presence of other cations and anions inhibited copper uptake in the following order: for the cations, Mn2+ ≫ Zn2+ > Cd2+ > Mg2+ > Ca2+; for the anions, EDTA ≫ SO ≫ Cl−. The biosorption process was fully reversible and regenerated columns showed undiminished performance.
Vigneswaran, S, Manandhar, UK, Janssens, JG & Ben Aim, R 1970, 'Mathematical modelling of the effect of size distribution of suspended particles in deep-bed filtration - Experimental testing', Water Supply.
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A mathematical model for granular bed filtration incorporating the influent particle size distribution was tested using extensive experimental results obtained from laboratory-scale filter experiments with sikron particles. This study gives an approach which reduces the nos. of model coefficients to be estimated by expressing these as functions of particle diameter. The predicted result fits reasonably well for the case of finer particles than the bigger ones, specially at the ripening stage.
