Design, Construction, and Evaluation of a Scaled-Up Air-Cathode Microbial Fuel Cell

Presented in this report is an investigation of the design, construction, and operation of scaled-up cloth electrode assembly (CEA) air-cathode microbial fuel cells (MFCs). 40 mL MFCs were designed and constructed using either single or double CEAs with carbon cloth electrodes. The MFCs were evaluated using acetate media, municipal wastewater, and brewing wastewater with mixed culture originally enriched from municipal wastewater. A single CEA MFC using acetate reached a power density of 3450 mW/m2 (860 W/m3), 192% of a similar 2.5 mL MFC. This was possibly due to increased platinum loading and an improved microbial community. Double CEA MFC power density losses were likely due to biofilm accumulation between CEA layers, changes in the microbial community, and greater areas for oxygen diffusion into media. The 12 W/m3 generated with municipal wastewater was much lower than that produced with acetate medium due to low chemical oxygen demand (COD) and pH buffer concentrations in the wastewater. 47% of COD in brewing wastewater was removed while producing a power density 81% lower than acetate (160 W/m3) due to the lack of sufficient pH control. Further efforts are needed to improve CEA fabrication to prevent unintended biofilm growth within the CEA structure and optimize the environmental and operational condition for wastewater treatment