Electrochemical anaerobic fluidized bed membrane bioreactor: Sustainable management of membrane fouling and enhancement of methane production rate in greywater treatment

Abstract

A novel electrochemical anaerobic fluidized bed membrane bioreactor (E-AFMBR) was developed and applied to enhance both methane production kinetics and antifouling efficiency from synthetic greywater treatment. A unique feature of the E-AFMBR is the integration of electrochemical interactions, driven by external voltage, with mechanical scouring actions caused by media fluidization across the ceramic membrane surface to ensure sustainable operation. Compared to the control AFMBR (C-AFMBR) operated under the same organic loading rate (OLR) without external voltage, the E-AFMBR produced 48.9 % more biomethane at an applied voltage of -1.00 V. Furthermore, antifouling efficiency in the E-AFMBR was 50 % higher than that in the C-AFMBR. These synergistic effects were more pronounced at longer hydraulic retention times (HRTs) or lower set-point permeate fluxes. The electrical energy produced by biomethane was about 50 % higher in the E-AFMBR than in the CAFMBR. Microbial community analysis revealed that hydrogenotrophic Methanobacterium and electroactive Geobacter were more dominant in the E-AFMBR than in the C-AFMBR. The findings of this study strongly support the E-AFMBR as one of the most promising anaerobic membrane bioreactor (AnMBR) technologies for achieving energy-positive, decentralized wastewater treatment and resource recovery by enhancing both antifouling efficiency and methane production rate.