Optimization of Biogas Liquid Waste from Livestock Manure as a Source of Renewable Energy through Microbial Fuel Cell (MFC) Technology

This study examines the potential of biogas liquid waste as a source of electrical energy through microbial fuel cell (MFC) technology. The results showed that biogas effluent in one-room MFC produced a maximum voltage of 1302.2 mV. In the two-room MFC with KMnO4 electrolyte, the voltage reached 1084.3 mV with an electric current of 0.1 mA. At the same time, the two-chamber MFC with K2Cr2O4 advanced a maximum voltage of 1675.8 mV and an electric current of 0.99 mA. Characterization of the MFC substrate showed a decrease in organic matter of biogas liquid waste, with C-organic content of 2.20%, total nitrogen of 1.85%, and C/N ratio of 1.19. The COD value decreased to 500.96 mg/L, while the BOD level decreased to 300.23 mg/L. Bacteria in MFC from biogas effluent are dominantly Gram-positive with rod and Sarcina forms, except for one Gram-negative isolate in the form of Spirillum.