Using mixed sludge-derived short-chain fatty acids enhances power generation of microbial fuel cells

摘要

Microbial fuel cell (MFC) has drawn much attention in recent years, because it can produce electricity from sewage and waste. This paper reported that the fermentation of primary and secondary sludges (i.e., mixed sludge) tinder the combined use of surfactant and alkaline pH condition highly improved the production of SCFAs, and using mixed sludge-derived SCFAs as the fuel could significantly enhance the performance of electricity generation of MFCs (630 mV versus 405 mV). The data indicated that the maximal SCFA production under the combined condition reached 2150 mg COD/L, which was much higher than that of the control (160 mg COD/L). The mechanism investigation showed that the combined strategy had greater sludge solubilization, higher protein hydrolysis and lower activity of methanogens. Fluorescence in situ hybridization analysis revealed that the abundance of bacteria was significantly increased, whereas that of archaea was decreased by fermentation under the combined condition. Therefore, the reuse of primary and secondary sludges under the combined use of surfactant and alkaline pH condition can be a good approach to highly improve the power generation of MFCs.