Effect of Microbial Community Structure of Activated Sludge on Membrane Fouling Development in A/O-MBR

摘要

In this study, the influence of difference in the microbial community structure of activated sludge on the membrane fouling of the membrane bioreactor (MBR) under low organic loading rate conditions were investigated. 2 MBR was operated in duplicate under low temperature condition of R_L (12.9°C) and high temperature conditions of R_(H1) and R_(H2) (25.8°C and 26.3°C), respectively. During the MBR operation, periodically collecting the activated sludge samples and the membrane surface biofilm and sludge samples, where membrane fouling occurred, were collected and analyzed the microbial community structure based on the 16S rRNA gene sequence. As the result, membrane fouling was developed under R_L and R_(H1) conditions. The microbial community analysis of activated sludge on each MBR suggested that mechanism of membrane fouling was different under low temperature R_L and high temperature R_(H1) conditions. In the R_L condition, an uncultured OD1 bacteria was predominant in the biofilm, and TM6 bacteria was predominant in the biofilm of R_(H1) condition MBR. On the other hand, Candidatus Promineofilum (phylum Chloroflexi), which is reported as EPS degradation bacteria, was predominant genus in the MBR of R_(H2) condition and it was thought that it might be leads to membrane fouling mitigation.