Methanogenesis Control using 2-Bromoethanesulfonate for Enhanced Power Recovery from Sewage Sludge in Air-cathode Microbial Fuel Cells

Coulombic efficiencies (CE) of microbial fuel cells (MFCs) treating real organic wastes are generally low. Methanogenesis is a major factor reducing CE by diverting electrons to methanogens rather than electrochemically active bacteria. In this study, batch tests were conducted to enhance power recovery in sludge-fed MFCs by using 2-bromoethanesulfonate (BES) to control methanogenesis. Results showed that 0.5 mM BES effectively inhibited methane production in the sludge MFCs. In the presence of BES, the MFC reactor yielded a maximum voltage of 0.62 V and a maximum power density of 115 mW/m2, and CE increased from 4.1% to 7.8%. The cyclic voltammetry and DGGE analyses showed different catalytic behavior and microbial community of anode biofilm as a consequence of BES addition. As a first report using a complex feed, this study demonstrated that power recovery from complex organic wastes in MFCs can be improved by methanogenesis suppression with low dosage of BES.