A microbial fuel cell (MFC) is a system that can integrate electricity generation and, at the same time, contribute to decontaminating wastewater, becoming an eco-friendly technology with the environment. In this research, microbial fuel cells with graphite and aluminum electrodes were used at different sizes: 9, 25and 64 cm2, and a wastewater sample obtained from a rural location in Peru was used as substrate. The MFCs parameters of voltage, current and conductivity were monitored for 12 days, for the generation of electricity; and the parameters of Chemical Oxygen Demand (COD), Thermotolerant Coliforms, Turbidity and pH, for wastewater treatment. The MFCs with electrodes of 64 cm2 were the ones that had the highest efficiency in the production of electricity, because they generated higher voltage, current and conductivity throughout the days evaluated, with peaks of 0.22 V, 0.08 mA and...