Non-catalyzed microbial fuel cell (MFC) with open air cathode for bioelectricity generation during acidogenic wastewater treatment

Abstract

Single chambered mediatorless microbial fuel cell (MFC Nafion-117 membrane) fabricated with non-catalyzed electrodes was operated with open-air cathode to evaluate bioelectricity generation from domestic wastewater under acidogenic conditions (pH, 6) using anaerobic mixed consortia as anodic biocatalyst. Experimental data illustrated the feasibility of bioelectricity generation from domestic wastewater treatment. A steady increase in MFC performance was observed from the first cycle (0.248 V; 27.3 mW/m 2; 1.06 W/kg COD R) during the startup phase prior to stabilization on fourth cycle (0.449 V; 144.6 mW/m 2; 4.64 W/kg COD R). Sharp increase in power generation was observed after the fourth hour (125.4 mW/m 2; 289.61 mA/m 2) which continued up to the sixth hour (155.92 mW/m 2; 325.51 mA/m 2) and gradually decreased thereafter. Voltammogram evidenced clear redox peaks (E 0′, − 0.334 V) related to redox mediator NAD +/NADH (E 0′, − 0.32 V) suggesting a strong reducing phase. Higher energy (1.33 J) was observed at the fourth hour in concurrence with the effective electron discharge and higher substrate degradation.