High-quality effluent and electricity production from non-CEM based flow-through type microbial fuel cell

A new flow-through type microbial fuel cell (MFC) system was developed for practical application as a wastewater treatment process. The ultrafiltration MFC (UF-MFC), which has a UF membrane instead of an expensive cation exchange membrane (CEM) as a separator, was designed to continuously filter the anode chamber solution to cathode chamber via UF membrane. Through the UF-MFC system, high-quality effluent and electricity generation can be simultaneously achieved by the two different wastewater treatment processes applied, e.g., a biological organic pollutant removal in the anode chamber by electrochemically active bacteria and a physical filtration by UF membrane. The maximum power density of the UF-MFC was 53.5 mW/m2, lower than the power density shown by comparison with a Nafion based two-chambered MFC (55.7 mW/m2). However, the UF-MFC continuously produced high-quality effluent that did not need further post-treatment processes, showing a high and stable COD removal efficiency (>90%), and high rejection rate for total coliform (>97%) and suspended solids during 20 d operation. This study confirmed that UF-MFC s could be a promising technology for both of efficient wastewater treatment and energy recovery from wastewater in future wastewater treatment plants.

• A new flow-through type MFC equipped with a UF membrane instead of CEM is proposed.
• High-quality effluent and electricity can be simultaneously achieved in UF-MFC.
• Maximum power density of UF-MFC was 53.5 mW/m2.
• High removal rate was observed for COD and total coliform (90% and 97% each).
• The pH in both of chambers of the UF-MFC was kept around neutral.