Alternative Biological Process for Livestock Manure Utilization and Energy Production Using Microbial Fuel Cells

Abstract

Carbon-based porous materials are most widely used for Microbial Fuel Cells (MFC) based on their unique properties facilitating and allowing the development of high surface area electrode. The electrochemically active layer of the electrode was prepared using two types of catalysts: activated carbon (Norit NK) and activated carbon promoted with CoTMPP (AC/CoTMPP). Mobilization of phosphate ions in the liquid phase was observed during the process of livestock manure treatment. From 20 mg l−1 initially, the concentration of dissolved phosphates reached 100 mg l−1 after 96 h. Increased concentration of ammonium ions in the medium was also observed, indicating ongoing anaerobic mineralization of the organic matter. The processes taking place in the bio electrochemical reactor used result in recovery of nutrients and production of energy. A maximum current density of 140 μА cm−2 was reached during the MFC operation. The chemical oxygen demand (COD) removal rates were relatively high (above 2 g O2/L/h) for both differently catalyzed cathode configurations. As widely reported elsewhere, the electrochemical results confirm that a gas-diffusion electrode using activated carbon catalyst is very well suited as a positive electrode for use in bio electrochemical systems.