Design of a Two-Chamber Microbial Fuel Cell Without a Proton Exchange Membrane for Electricity Generation from Food Waste

Abstract

A conventional biomass-fired power plant requires substantial construction costs, making its implementation difficult in rural areas of developing countries. In contrast, microbial fuel cell (MFC) technology offers numerous benefits over conventional plants; however, its performance is currently inadequate and requires improvement before it can be deployed. This study proposed a new design for the anode chamber of a two-chamber MFC without a proton exchange membrane when food waste is used as a substrate. Different configurations of the anode chamber, including those with and without a soil layer and different anode positions, were investigated. The effects of each structure on MFC performance were investigated by measuring temporal changes in the cathode potential and examining the electrical conductivity (EC), oxidation–reduction potential (ORP) of the cathode water, and electrical current of MFC. The analysis of EC and ORP variations revealed that the introduction of a soil layer in the anode chamber resulted in lower EC values and higher cathode potentials, indicating that the soil layer acted as a filter to reduce the diffusion of ions from the anode chamber to the cathode chamber. However, this adsorption process increased the ohmic losses in the MFC system and decreased the current density. In the designs without a soil layer, when the anode was installed in the steelmaking slag (SS) layer, a higher cathode potential was observed compared with the design in which the anode was placed on the SS layer. Consequently, this higher potential induced a higher current density. However, without the exchange of cathode water, the current density decreased temporally, and no significant difference in the current density was observed between these designs during the first 7 days after generating electrical current. Therefore, placing the anode on the SS layer is a suitable design for recovering electricity from food waste.