The traditional treatment of sludge methods are high energy-consumption and expensive processes. Due to the increasing awareness considering risks for the global environment and human health, appropriate treatments of sewage sludge are urgently expected. A novel flow fuel cell technology was reported herein which could convert sewage sludge to electricity directly with high power output. In this flow fuel cell, chemically stable and completely regenerable polyoxometalates (POMs) were used as both catalysts and charge carriers. Thermal induced charge transfer from sludge organisms to POM was successfully used to power the flow fuel cell. The power density of the cell could achieve as high as 50 mW/cm(2), which is 100 times higher than the output of microbial sludge fuel cell reported in literature. Catalyst recyclability was investigated and the POMs were demonstrated to be effective to degrade sludge and transfer electrons in the fuel cell system after four rounds. (C) 2017 Elsevier Ltd. All rights reserved.