Microfiltration membrane fouling and cake behavior during algal filtration

Abstract

This study was carried out to investigate the membrane fouling phenomena due to algal deposition and to understand the nature of the cake deposited on the membrane while treating the algae-laden water by membrane filtration. To accomplish this, batch experiments in dead end mode were carried out using Chlorella algae to investigate the effect of feed concentration and transmembrane pressure (TMP) on cake resistance using cellulose ester and polyvinylidene difluoride (PVDF) membranes. It was found that algae can cause significant fouling of both the cellulose ester and PVDF membranes. Fouling due to algae is quite complex because these cells release extracellular organic matter (EOM) which significantly increases the resistance. The cake resistance offered by the Chlorella algae was independent of the membrane materials considered; thus the interaction between the membrane material and Chlorella cells was not important in the resistance development. It was also found that the cake deposited on the membrane was compressible in nature with a compressibility index of 0.439.