Control and modeling of membrane fouling due to microorganism growth by UV pretreatment

Control of membrane-fouling is an important topic for extending continuous running time and reducing the frequency of chemical cleaning in membrane processes. Since the microorganism contribution to membrane fouling was considered to be significant, UV was thought to be effective to control membrane fouling In this study, a pilot plant scale MF-membrane system (flow rate = 5 m(3)d(-1)) was operated in order to investigate the effect of UV pretreatment. As the experimental results, it was found that UV irradiation prevented the membrane fouling by control the microorganism concentration in the feed. And the continuous running time of membrane was extended 6 times longer than that of a process without UV pretreatment. In order to know how UV pretreatment prevented fouling, we also investigated the residual bactericidal effect which persists in water even after UV irradiation. However, the residual bactericidal effect wasn't observed in our experiment therefore inhibition of microorganism growth by the residual effect in the membrane module could be ignored. We developed the theoretical model ed microorganism growth on membrane as a membrane fouling material. This model can explain the observed membrana fouling due to microorganism growth. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.