Decomposition of EPS on the membrane surface and its influence on the fouling mechanism in MBRs

This study is aimed at elucidating the mechanism of the chan-e of molecular weight distribution of EPS by bacterial activities after being attached on the membrane Surface and the influence of EPS on the membrane surface on membrane fouling in a laboratory-scale MBR reactor. Change of EPS amount after accumulation on the membrane Surface was measured Under a non-substrate-fed condition. High molecular weight EPS (more than 1,000 kDa) accumulated on the membrane Surface was found to be decomposed to smaller molecular-weight EPS and was finally mineralised decreasing the filtration resistance of the membrane. This natural recovery mechanism from fouling was explained by a mathematical model considering the production and decomposition of high- and low-molecular weight EPS on the membrane Surface.