Control and modeling of membrane fouling due to microorganism growth by UVpretreatment

Control of membrane-fouling is an important topic for extending continuous running time and reducing the frequency of chemical cleaning in membrane pr ocesses. Since the microorganism contribution to membrane fouling was consi dered 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 pretrea tment. As the experimental results, it was found that UV irradiation preven ted the membrane fouling by control the microorganism concentration in the feed. And the continuous running time of membrane was extended 6 times long er than that of a process without UV pretreatment. In order to know how UV pretreatment prevented fouling, we also investigated the residual bacterici dal effect which persists in water even after UV irradiation. However, the residual bactericidal effect wasn't observed in our experiment therefore in hibition of microorganism growth by the residual effect in the membrane mod ule could be ignored. We developed the theoretical model ed microorganism g rowth on membrane as a membrane fouling material. This model can explain th e observed membrana fouling due to microorganism growth. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.