Effects of organic loading rates on the continuous electricity generation from fermented wastewater using a single-chamber microbial fuel cell

Abstract

Novel coupling of single-chamber microbial fuel cells (MFCs) with granular activated carbon anodes were constructed, and their ability to produce electricity from fermented wastewater operating in continuous mode was investigated. MFCs treating real fermented wastewater can generate a power density of approximately 1884 mW/m 3, which is equivalent to approximately 51.5% of that obtained from the MFCs (3664 mW/m 3) using acetate at the same organic loading rate (OLR) of 1.92 g/L d. As the OLR was increased in a stepwise fashion, power density increased to 2981 mW/m 3 at an OLR of 3.84 g/L d. The corresponding energy production was 268 kJ/m 3 d. The decrease in the power density was mainly due to the higher internal resistance resulted from complex substrate. Based on the electrode characteristics, it was verified that colloidal particulates and complex organics in the real fermented wastewater not only lowered power density but also played a role as rate-limiting factors in the continuous generation of electricity.