Effect of Different Substrates and Concentrations on the Performance of Double Chamber Microbial Fuel Cell

Abstract

Microbial fuel cell (MFC) provides new opportunities for energy generation and wastewater treatment through conversion of organic matter into electricity by electrogenic bacteria. This study investigates the effect of different types and concentrations of substrates on the performance of double chamber microbial fuel cell (DCMFC). Three mediators-less laboratory scale DCMFCs were used in this study, which were equipped with graphite electrode and cation exchange membrane. The MFCs were fed with three different types of substrates (glucose, acetate and sucrose) at concentration of 1000 mg COD/L. The selected substrate (acetate) was studied for three different concentrations of 500, 2000 and 3000 mg/L of COD. Electricity generation and organic matter removal efficiency of MFCs were measured for evaluation of their performance. Results demonstrate that power production depends strongly on the types and concentrations of substrate used. The MFCs fed with acetate, sucrose and glucose produced maximum power density of 91, 64 and 51 mW/m2 respectively. In contrast, COD removal efficiency of 79, 77 and 60% was recorded for MFCs fed with glucose, acetate and sucrose respectively. Coulombic efficiency (CE) for all substrates indicate that only 0.7-1.3% of COD was utilized in current production. The polarization curve shows that ohmic losses were dominant in DCMFCs established for all three substrates. The performance of MFC was found to be affected by the concentration of substrates. Polarization and power curves established for different concentrations of acetate show that maximum power density of 33, 110 and 114 mW/m2 and internal resistance of and 871, 370 and 301 Ω are produced at concentrations of 500, 2000, and 3000 mg/L of COD respectively.