The Effect of External Resistance on the Performance of an Annular Single Chamber Microbial Fuel Cell (ASCMFC) Using Chocolate Industry Wastewater

The following goals were followed by the study to treat wastewater and produce power and electricity simultaneously using a single chamber microbial fuel cell (SCMFC). Firstly, the stainless-steel mesh with graphite coating as the anode brought about a porous surface for the proper growth and attachment of the biofilm. Secondly, using the anode in the spiral geometry, the surface of the anode electrode increased and the time for the substrate to reach the microorganisms decreased. Wastewater of the chocolate industry was used as substrate. In this study, two ASCMFCs with a volume of 90 cm³, with a completely identical configuration and the only difference in the electrode distance, were examined discontinuously. The maximum voltage values in the open circuit state and the power density for the first system with an electrode distance of 1.3 cm were obtained as 742 mV and 7.98 W/m³, respectively. The second fuel cell was built to optimize the electrode distance and started at three electrode distances of 1, 0.7 and 0.4 cm, and its performance was examined and compared with the results obtained from the first fuel cell at these three distances. The maximum voltage in the open circuit mode was obtained at the optimal electrode distance of 0.7 cm and 856 mV. The experiments were repeated to obtain the maximum current and power density. The maximum power density at the optimal distance was 22.898 W/m³. The performance of the microbial fuel cell as an electricity generator is given according to the polarization behavior and the cell potential. In the next stages of the experiments, the input substrate concentration and chemical oxygen demand were analyzed. A significant decrease in turbidity and chemical oxygen demand was seen after 96 hours, respectively, at 79.66% and 91.2%.