Continuous electricity generation in stacked air cathode microbial fuel cell treating domestic wastewater

This study examined the continuous performance of air cathode MFC stacks for domestic wastewater treatments at two different temperatures (23 +/- 3 degrees C and 30 +/- 1 degrees C) and organic loading rates to determine the effects of the electrode connection and hydraulic flow mode on the stack performance. The power density and process stability were affected significantly by the electrode connection type, flow mode, and operating parameters. The parallel electrode connection system (in series flow mode) had benefits of COD removal, Coulombic efficiency and maximal power density due to the higher stability of the ORP in overall cells. The highest power density of 420 mW/m(2) (12.8 W/m(3)) was achieved in series flow and parallel connection mode at an organic loading rate of 25.6 g COD/L-d (HRT of 0.33 h) under mesophilic conditions, achieving a COD removal of 44%. The results highlight the importance of prefermentation process in the application of a stacked MFC for an actual wastewater treatment. (C) 2013 Elsevier Ltd. All rights reserved.