Performance of air cathode earthen pot microbial fuel cell for simultaneous wastewater treatment with bioelectricity generation

Air cathode earthen pot microbial fuel cell (ACEMFC) was made using low cost earthen pots as a separator coated with conductive carbon black on the exterior to work as a cathode. ACEMFC was operated in fed-batch mode with synthetic wastewater containing acetate as anolyte (0.40 L) at a fixed external resistance of 100 Ω. Carbon cloth (projected surface area of 32 cm ²) was used as anode. Sludge collected from the bottom of septic tank was used as an anodic inoculum. An average OCV of 0.62 ± 0.1 V, a Coulombic efficiency of 17 ± 4%, and a peak volumetric power density of 3.56 ± 0.2 W.m^-3 was obtained during steady state condition. It was found that ACEMFC produced 45% higher power output when compared with conventional dual chamber earthen pot MFC. This low cost ACEMFC, with total production cost of about 1.5$, as per Indian market, demonstrated its utility as a wastewater treatment and onsite power generation device. However, biofouling was observed on cathode surface of ACEMFC after a couple of weeks of operation resulting in overall performance reduction, which needs to be improved to make this device sustainable for long term operation.