Treatment of domestic and distillery wastewater in high surface microbial fuel cells

Microbial fuel cells (MFCs) are bio-electrochemical devices that couple organic carbon removal from wastewater and electricity production. Full-scale application of MFCs in a wastewater treatment plant (WWTP) requires high surface, lowcost electrodes to maximize microbial growth and power output. In this study, a high surface MFC anode is constructed by interlacing carbon yarn with stainless steel. The anode is arranged in a double-air cathode MFC configuration with 6 ± 1 Ω internal resistance. When closed on 100 Ω external resistances in batch mode, the MFCs produce maximum power densities of 621 ± 17 and 364 ± 11 mW m−2 for domestic and distillery wastewater, respectively. The chemical oxygen demand (COD) removal is 68% and 58% with a columbic efficiency of 47% and 27% for domestic and distillery wastewater, respectively. The biofouling layer on the Nafion membrane is twofold thicker in the domestic wastewater MFC, thereby suggesting that the power output and COD removal in distillery wastewater MFC are not limited by the cation transport across the membrane, but rather by the chemical composition of the distillery wastewater that does not support an efficient electrochemically active microbial community.