Effect of particle size distributions on membrane performance and fouling in microfiltration of polydispersed suspensions

Abstract

Microfiltration has been increasingly used for the removal of particulate matter in water purification and wastewater treatment. A major operational constraint in microfiltration is the rapid reduction in permeate flux as a result of membrane fouling due to high solids loading. In this study, suspensions of different particle size distributions were prepared and used in dead-end microfiltraion experiments. The effect of particle size distribution on trans-membrane pressure, and permeation flux was investigated. The mechanisms of pore blocking and cake formation were characterized through theoretical models, together with surface examination using SEM. Results show that membrane fouling transits from initial pore blocking to a process eventually dominated by cake formation, and the transition is greatly affected by particle size distribution in the suspensions.