Assessment of an anaerobic membrane bio-electrochemical reactor (AnMBER) for wastewater treatment and energy recovery

• An anaerobic membrane bio-electrochemical (AnMBER) system was developed.
• Stable electricity (0.132 V) was produced in AnMBER while treating wastewater.
• Removal efficiencies of COD and nitrate averaged 91.6 and 94.8%, respectively.
• Lower SMP content was beneficial for the fouling limitation in AnMBER.

Microbial fuel cells (MFCs) have a great potential for cost-effective wastewater treatment; however, the effluent quality from MFC is not always satisfied. In this study, an anaerobic membrane bio-electrochemical reactor (AnMBER) with an anaerobic membrane bioreactor (AnMBR) equipped with hollow-fiber microfiltration (MF) membranes directly serving as the cathodic chamber of a dual-chamber MFC was developed. Over an operational period of more than 600 h, the AnMBER system (with 100 Ω resistor) was able to generate continuous bio-electricity (0.132 V), with a maximum power density of 1.16 W m−3 net cathodic chamber (NCC), and achieved high removal efficiencies of chemical oxygen demand (COD) (91.6%) and nitrate (94.8%). Furthermore, compared with a control AnMBR (with open circuit), membrane fouling was mitigated significantly in the AnMBER system, which was mainly attributed the lower particle zeta potential and lower amount of soluble microbial products (SMP) in the cathodic mixed liquor. These results demonstrate that integrating the anaerobic MF filtration sequentially to MFCs is a feasible approach to accomplish simultaneous efficient wastewater treatment and energy recovery and also raises the possibility of using MFCs as a means to minimize fouling in combined systems by improving the mixed liquor properties.