In situ biofilm removal from air cathodes in microbial fuel cells treating domestic wastewater.

One challenge in using microbial fuel cells (MFCs) for wastewater treatment is the reduction in performance over time due to cathode fouling. An in-situ technique was developed to clean air cathodes using magnets on either side of the electrode, with the air-side magnet moved to clean the water-side magnet by scraping off the biofilm. The power output of the magnet-cleaned cathodes after one month of operation was 132 ± 7 mW m, which was 42% higher than the controls with no magnet (93 ± 4 mW m) (no separator, NS), and 110% higher (116 ± 4 mW m) than controls with separators (Sp, 55 ± 7 mW m). Cleaning cathodes using magnets reduced the biofilm by 75% (NS) and 28% (Sp). The in-situ cleaning technique thus improved the performance of the MFC over time by reducing biofouling due to biofilm formation on the air cathodes.