Microbial fuel cells (MFC) in the treatment of dairy wastewater

Abstract

Microbial Fuel Cells (MFC) appear to offer a feasible alternative to conventional wastewater treatment techniques; thus, constructing and testing MFCs for this purpose was accomplished in this research. The experiments were carried out in two stage; In first stage, synthetic dairy wastewater was used as substrate in an anode chamber using Saccharomyces cerevisiae at different pH values (5, 6, 7, and 8) and different operational temperatures (25, 30, 34 °C in order to evaluate the performance of MFC in term of COD reduction and electricity generation, while in the second stage, the MFC testing was conducted using real dairy wastewater with an initial concentration of COD equal to 2,610 mg/L, inoculated with Saccharomyces cerevisiae in an anaerobic anode chamber under optimum operation conditions. The results revealed that increasing operation temperature had a significant effect on COD reduction and operation time. The optimum pH and temperature were 6 and 34 °C, respectively. After treatment of the dairy wastewater, the COD, TSS, TDS, EC, SO4, and NO3 removal efficiencies of the MFC were found to be 92%, 79.3%, 62.5%, 38.6%, and 60%, respectively. These removal ratios confirm ability of living microorganisms to digest the organic matter present in dairy wastewater to produce electrical power, with maximum values of 850 mV and 28 μA produced for voltage and current, respectively. Microbial Fuel Cell technology thus offers an efficient approach to both dairy wastewater treatment and energy recovery.