Microbial Communities on the Submerged Membranes in Full-Scale Membrane Bioreactors Treating Municipal Wastewater

Abstract

This study used 16S rRNA gene-based terminal-restriction fragment length polymorphism (T-RFLP) analysis to investigate full-scale membrane bioreactors (MBRs), which mainly treat domestic wastewater, with specific examination of the microbial communities on membrane biofilms. Using cluster analysis and principal component analysis based on T-RF profiles, the microbial community structures of biofilms on moderately fouled membranes were distinguished from those on slightly fouled membranes and from activated sludge in the MBRs. Furthermore, biofilms on the severely fouled membranes hosted characteristic microbial communities under high-flux operation. The microbial community structures showed correlation with transmembrane pressure and the humus and iron biofilm contents. The microbial communities in membrane biofilms can indicate the fouling state.