Simultaneous power generation and sewage sludge stabilization using an air cathode-MFCs

Abstract In recent decades, the generation of bioenergy from wastes as a cost-effective and environmentally friendly source has attracted the attention of researchers. Among waste materials, sewage sludge contains a high amount of organic matter that can be stabilized and converted directly into electricity via microbial fuel cells. Here in this study, the effects of different concentrations of mixed liquor suspended solid (MLSS) and initial chemical oxygen demand (COD) concentration of the municipal sewage sludge (secondary excess sludge) on the electricity generation in an air cathode microbial fuel cells (MFCs) have been investigated. The results confirmed significant effects of MLSS and COD on the sludge stabilization and power generation. The secondary excess sludge when MLSS was 10000 mgL−1 produced maximum power density and current density of 27.65 Wm-3 and 473.5 mAm−3, respectively. The maximum MLSS removal efficiency for aerobic and anaerobic compartments was 50% and 36%, respectively. This result represented that the applied MFC is suitable for treating secondary excess sludge and energy recovery. Furthermore, the process in the cathode chamber was more efficient for sludge stabilization than the anodic process.