Effect of different concentrations of substrate in microbial fuel cells toward bioenergy recovery and simultaneous wastewater treatment

Microbial fuel cells (MFCS) is a promising and expanding technology able to eliminate various
pollutants of wastewater while converting its chemical energy into power energy using
biocatalysts. The potential application of double-chamber microbial fuel cell (DC-MFC) for
chemical oxygen demand (COD) removal and generated power from wastewater in the different
conditions is investigated. DC-MFC is operated with anaerobic sludge as an active biocatalyst in
an anode section, an aerobic cathode section and a Nafion117 membrane as a separator. The
performance of the bioreactor is determined with different concentrations of chemical oxygen
demand (COD) loadings in the MFC process, in terms of COD removal, power generation and
columbic efficiencies. The results illustrated that COD removal efficiency increased at the high
concentrations of organic matter. So that at COD concentration of 2000.0 mg/L the highest COD
removal efficiency (84%) was obtained. But with increasing substrate initial concentration to
10000.0 mg/L the efficiency decreased to 79%. The important outputs of the system like the
highest voltage, maximum generated power, current density, and energy efficiency with the
100,000 mg/L COD are 447 mV, 50.7 mW/m2, 570.0 mA/m2, and 18.6%, respectively. The optical
density levels increased due to bacterial growth while pH severely decreased in the anode
chamber when using high-concentration substrates in the MFC