Role of transparent exopolymer particles (TEP) in initial bacterial deposition and biofilm formation on reverse osmosis (RO) membrane

The fouling potential of transparent exopolymer particles (TEP) was evaluated to reveal its role in the biofouling mechanism of reverse osmosis (RO) membrane process. A methodology to determine the fouling potential of TEP was systematically developed based on cake filtration theory. The resulting cake fouling index of TEP (CFI_TEP) was then correlated to initial bacterial deposition observed in RO biofouling tests. Alginic acid was employed to simulate TEP and Pseudomonas aeruginosa PA14 was inoculated for biofouling test. The results showed that the fouling propensity of TEP could be assessed by cake fouling potential of particulate TEP (>0.45μm). Furthermore, the analysis of biofouled RO membranes indicated that bacterial deposition on RO membranes was enhanced significantly with increasing the cake fouling potential of TEP (i.e., CFI_TEP). This work demonstrated the importance of TEP at the initial stage of biofilm formation, suggesting TEP control by pretreatment for mitigating biofouling in RO applications.