Electricity generation in a microbial fuel cell using yogurt wastewater under alkaline conditions

Abstract

The aim of this study was to investigate the feasibility of electricity generation in a microbial fuel cell (MFC) using yogurt wastewater as the substrate under alkaline conditions. Different initial COD concentrations of yogurt wastewater (i.e., 1.0 ± 0.1, 2.0 ± 0.1, 5.0 ± 0.5, 8.0 ± 0.6, and 13.0 ± 1.0 g L⁻¹) at pH 10.5 were tested in the single-chamber air-cathode MFC. The maximum power density reached 1043 ± 100 mW m⁻², which was much higher than those previously reported using food-processing wastewater under alkaline conditions. The COD and NH₄-N removal efficiencies were more than 87% and 74%, respectively. With the increase of COD concentration in yogurt wastewater, the internal resistance in the MFC increased but the bacterial viability in the anode biofilm decreased, resulting in a decrease of electricity generation in the MFC. Geoalkalibacter with a relative abundance of 12.9–49.9% dominated the bacterial community in the anode biofilm. Our results should be useful in expanding the application scope of MFCs in wastewater treatment under alkaline conditions.