Multi-response parametric optimization and biofilm studies of low-cost ceramic microbial fuel cell for dairy wastewater treatment

Microbial Fuel Cells (MFCs) can treat wastewater, generating electricity simultaneously. However, major issues for up-scaling MFCs are expensive materials and low power densities. In this study, single-chamber MFCs made of low-cost materials i.e., earthen pot separator, stainless-steel mesh electrodes, cathode catalyst as activated carbon and manganese oxide mixture were used; cost of materials totaling less than a dollar. Using dairy wastewater as substrate, system optimization was done by studying effects of pH, external resistance, and co-substrate using Response Surface Methodology (RSM) for maximization of power density, COD removal percentage and columbic efficiency. Acidic pH, higher external resistance, and acetic acid co-substrate conditions showed optimized results. Cyclic Voltammetry and Electrochemical Impedance Spectroscopy were tested, studying effects of pH on biofilm formation. Consistent biofilm seen in case of neutral pH than pH 6 & pH 8. RSM had proposed quadratic models for all three parameters. Confirmation run carried out showed satisfactory results.