Biofouling Control by Facultative Quorum Quenching Bacteria in Anaerobic Membrane Bioreactors for High-Strength Wastewater Treatment

Abstract

Quorum quenching (QQ) by bacterial strains has been demonstrated to be a cost-efficient approach for biofouling control in an anaerobic membrane bioreactor (AnMBR). In this study, a facultative anaerobic QQ consortium was screened and encapsulated in beads (QQ beads) to mitigate biofouling in AnMBR for high-strength wastewater treatment. The operation time of membrane fouling in QQ-AnMBR was 3.5 times longer than that of control-AnMBR. The biofouling mitigation was attributed to the QQ effect on the reduction of quorum sensing signals and extracellular polymeric substances (EPS) in the cake layer. However, the retarded membrane biofouling and lower EPS in the QQ-AnMBR led to a higher level of irreversible membrane resistance. The addition of QQ beads enriched the genus Thauera and Methanothrix, while reduced the abundance of Methanosarcina. Moreover, the relative abundance of QQ-related genes in the cake layer increased from 0.014% in the Control-AnMBR to 0.022% in the QQ-AnMBR. These findings indicate significant promise for the facultative anaerobic QQ strains in implementing a biofouling strategy in AnMBR for high-strength wastewater treatment.