A modular Gravity-Driven Ultrafiltration (GDU) membrane system for contaminant removal: Dynamic flux modelling and its fouling study

Abstract

During flood or drought, water shortage is a critical issue due to the water contamination. Under this situation, gravitational driven ultrafiltration (GDU) membrane system which solely depends on hydrostatic pressure could be employed to provide the clean water for domestic usage. Due to the limitation of site accessibility during flood, a modular and batch type GDU membrane system is required for water filtration. In that case, prediction of the water level within the module which affected the hydrostatic pressure and effective filtration area over the time is important. The prediction of water level enables the design of the intermittent pumping frequencies for the optimum usage of energy. In this work, the removal efficiency of GDU system towards two common contaminants in water surface namely humic acid and calcium carbonate were tested. The highest removal efficiency of the GDU system towards humic acid, and calcium carbonate were recorded as 94.96 % and 99.19 % respectively. It was found that different feed solutions exhibited different fluxes declination profiles due to their distinctive fouling characteristic. A model was developed to predict the ideal dynamic flux of the membrane under the condition of reducing hydrostatic pressure and effective membrane area. Using the dynamic model, the resistance of the membrane and cake layer were determined. It was found that the filtration resistance is dominated by the cake layer resistance. River water test showed that GDU is an effective method for reclaiming the river water in removing the colour and turbidity.