Biosensor
Since the current generated from a microbial fuel cell is directly proportional to the energy content of wastewater used as the fuel, an MFC can be used to measure the solute concentration of wastewater (i.e. as a biosensor system).
The strength of wastewater is commonly evaluated as biochemical oxygen demand (BOD) values. BOD values are determined incubating samples for 5 days with proper source of microbes, usually activate sludge collected from sewage works. When BOD values are used as a real time control parameter, 5 days' incubation is too long.
An MFC-type BOD sensor can be used to measure real time BOD values. Oxygen and nitrate are preferred electron acceptors over the electrode reducing current generation from an MFC. MFC-type BOD sensors underestimate BOD values in the presence of these electron acceptors. This can be avoided by inhibiting aerobic and nitrate respirations in the MFC using terminal oxidase inhibitors such as cyanide and azide. This type of BOD sensor is commercially available.
Read more about this topic: Microbial Fuel Cell, Applications