Organic Flocculation as an Alternative for Wastewater Treatment

Microbial fuel cells are bio-electrochemical systems which are capable of producing electrical energy directly from chemical energy by utilizing exo-electrogenic bacteria capable of extracellular electron transfer (EET). These bacteria present in the anode chamber oxidize the substrate to produce electrons and protons. The produced electrons are transferred from anode later to cathode through external electrical circuits. MFC, when operated with wastewater as source of chemical energy, aids in containing the dual issues of energy crisis and waste reclamation. MFC confers numerous advantages over other waste to energy conversion systems like bio-methanation, gasification and incineration. It has a low environmental footprint, and the direct conversion of chemical to electrical energy reduces the conversion losses. MFC operated on a lab scale produced substantial power, but in a large-scale operation the power was not as expected. Extensive research into the factors affecting MFC power production has been carried out, and it has been found that both the physicochemical and biological factors influenced the overall MFC performance. The operating parameters include pH and concentration of waste stream, the inoculum used and the hydraulic retention time, whereas the physical and chemical factors such as electrode material, number of chambers and cathode system used also influence the performance of MFC. Hence, a complete study on the factors affecting power production is important to further improve the power production. In this chapter we will focus on the studies made on factors affecting power production in mediator-less MFCs, the modifications made in the system to improve the power production, future scope and challenges underlying the system. A special focus on MFC employing bio-anodes and the power harvesting system used has been made.