Attached-growth configuration outperforms continuously stirred tank anaerobic membrane bioreactors in alleviating membrane biofouling

Abstract

Biofouling impedes the performance of anaerobic membrane bioreactors (AnMBR). Two reactors, one as an up-flow attachment-growth AnMBR (UA-AnMBR) configuration, and the other, as a continuously stirred AnMBR (CS-AnMBR) were evaluated for differences in membrane fouling rate. TMP increment in UA-AnMBR was slower than CS-AnMBR, although both reactors had similar COD removal efficiency (ca. > 96%). Slower fouling rate for UA-AnMBR was related to lower total and viable cells, and thereby microbial activity compared to that in CS-AnMBR. Acinetobacter and Methanobacterium that played keystone roles in anaerobic biofilm formation were not consistently prevalent on the membranes connected to UA-AnMBR. This is in contrast to both Acinetobacter and Methanobacterium consistently prevalent on the membranes connected to CS-AnMBR. The findings suggest that UA-AnMBR can alleviate membrane biofouling through changes in microbial activity and profile dynamics, and would be a suitable reactor configuration to adopt to achieve an efficient AnMBR for municipal wastewater treatment.