Abstract
Although RO membrane system has been widely used, it often faces serious problems caused by the developments of biofilm on the membrane that lowers the efficiency. The biofilm is a complex mixture of organic polymers, microbial cells and sometimes larger organisms. In order to properly maintain and operate RO system, the understanding of biofilm is prerequisite. In this review, basic characteristics of microorganisms and experimental observations on the biofilm formation processes with special emphasis on microbial community structures are described and dis-cussed.
