The improving standard of living causes the increases in energy consumption and waste or wastewater production. The possibility of combining wastewater treatment and electricity production can be accomplished by means of a microbial fuel cell. The possibility of wastewater treatment using the Ni-Co alloy as cathode catalyst with KMnO4 catholyte for microbial fuel cells was presented in this paper. The measurements covered the comparison of changes in the concentration of COD, NH4+ and NO3- in the reactor without aeration, with aeration and using a microbial fuel cell (with Ni-Co cathode and KMnO4 catholyte). The reduction time for COD using a microbial fuel cell with the Ni-Co catalyst (and KMnO4 catholyte) is similar to the reduction time with aeration. It has been shown that the Ni-Co (with KMnO4 catholyte) can be used as cathode catalyst in microbial fuel cells. Unfortunately, in this case a constant delivery of catholyte is needed. The cell power of 15 mW and current density of 0.23 mA/cm2 were obtained in the analysed MFC.