Electricity generation from starch processing wastewater using microbial fuel cell technology

Microbial fuel cells (MFCs) represent a new method for simultaneous wastewater treatment and biological electricity generation. In this study, an air-cathode MFC with membrane electrode assembly was operated over four batch cycles (a total period of 140 d) and results indicated that starch processing wastewater containing 4852 mg/l of chemical oxygen demand could be used as substrate to produce electricity with this MFC. Maximum voltage output and power density of 490.8 mV and 239.4 mW/m2 (a current density of 893.3 mA/m2) were approached in the third cycle, which also had the minimum internal resistance of about 120 Ω and maximum coulombic efficiency of 8.0%. Removal efficiencies of chemical oxygen demand and ammonia-nitrogen increased as a function of time, and maximum amounted to 98.0% and 90.6%, respectively. Scanning electron microscope image revealed that short rod shaped bacillus were the dominant bacteria on the biofilm of the anode, whose electrochemical activity was proved by cyclic voltammetry. These results demonstrate that starch processing wastewater can be used for power generation in MFCs and also can be treated with high removal efficiencies of chemical oxygen demand and ammonia-nitrogen.