In-situ alkaline pretreatment of waste activated sludge in microbial fuel cell enhanced power production

Abstract

Energy recovery from waste activated sludge (WAS) by microbial fuel cell (MFC) can simultaneously address energy issue and environmental concerns. Pretreatments are vital to enhancing energy recovery and sludge reduction with WAS as power source in MFC. The commonly applied two-stage process, which separates WAS pretreatment with electricity generation, decreases the cost-effectiveness of MFC with WAS as power source. It is of great practical importance to investigate the feasibility of one-stage process for simultaneous sludge pretreatment and electricity generation. Herein, a one-stage alkaline MFC (anode chamber controlled at pH 9.0) is constructed to recover energy from in-situ alkaline pretreated WAS. Results show that alkaline MFC achieves excellent performance of electricity generation with high voltage output (0.74 V) and high power density (0.65 W m−2). The total chemical oxygen demand removal of WAS is >40%. No greenhouse gas (CH4 and CO2) are released from the alkaline MFC with WAS as power source. The enhanced electricity generation performance in the alkaline MFC is investigated through three aspects, including internal resistance, degradation of soluble organics, and shift of microbial community. This work offers a promising alternative for energy recovery with WAS as renewable power source.