Microbial fuel cell sensors for water quality early warning systems: Fundamentals, signal resolution, optimization and future challenges.

An early warning system is important to guarantee human health and ecological safety. Microbial fuel cell (MFC) sensor can achieve a self-sustainable monitoring without additional transducer or power sources. It would not limited by the main bottleneck of other contemporary MFC technologies, i.e., the low current density output, and is believed one of the most promising applications in the niche market of MFC technologies. This review is limited to MFC sensors for water quality early warning systems only, with emphasis on biochemical oxygen demand (BOD) and toxicity sensors. A comprehensive summary and discussion on sensor fabrication, operation, data representation, and optimization are provided. The MFC sensor is particularly promising to serve as a self-powered sensing device for in-situ and on-line environmental monitoring, as proved both in laboratory and field test. In addition, the main hurdles and future perspectives are discussed, as well as potential future research, which includes the following: separately lowering the detection limit or improving the concentration range dependent on the application of MFC for organic matter monitoring; further improving the sensitivity as well as lowering the recovery time of biofilm after a certain shock; developing the kinetic and/or empirical model in combining with the detection algorithm to distinguish the signal interference of complex aquatic environment, especially when the shock of BOD and toxicity occur simultaneously. [ABSTRACT FROM AUTHOR]