Establishing and Understanding the Electron Balance in Microbial Fuel Cells

Abstract

Microbial fuel cells (MFCs) have been intensively studied in the past decade as a promising alternative wastewater treatment technology. However, the critical mass balances such as carbon (or electrons) balances have not well addressed before. Clear understanding of a carbon balance in the anode of an MFC will help to identify electron distribution among different electron acceptors, and the limiting factors that divert electrons from electricity generation. In this study, the effect of substrate loading rate, sulfate, temperature, substrate type and nitrate concentration on MFC's performance were investigated. At different operation condition, the biomass, current, biogas, dissolved oxygen, sulfate and nitrate concentrations were monitored to make an electron balance. The results suggested that COD removal rate, current, biomass and biogas can increase with the increase of organic loading rate. The sulfate concentration has a negative effect on biogas production, but, it has a positive effect on the current, COD removal rate which is different from previous study. The substrate type (fermentative or un-fermentative) can increase the electricity production.