Effect of Temperature Variation on the Performance of Microbial Fuel Cells

The anode of a microbial fuel cell (MFC) was inoculated using recycling activated sludge and incubated at 25 degrees C (start-up temperature, denoted as 25 degrees C-stu) for 2 weeks, and the temperature was then stepwise changed to 35, 25, 45, and 25 degrees C. A maximum power density of 54 mWm(-2) and a current density of 348 mAm(-2) were observed at 25 degrees C-stu. The MFC performances at 35 and 45 degrees C were much lower compared to 25 degrees C-stu due to substrate limitations. After operation at 35 (11 days) and 45 degrees C (9 days), the temperature was switched back to the initial temperature of 25 degrees C, but the MFC performance did not recover to the initial level for 25 degrees C-stu. These results confirm that after MFC stabilization at a start-up temperature, the increase of MFC operating temperature could lead to a failure of the MFC system, indicating that the operating temperature of an MFC system for wastewater treatment should be stable and remain as identical to its start-up temperature as possible.