Wastewater Treatment and Energy Production Using a Baffled Microbial Fuel Cell

Abstract

Microbial fuel cells (MFCs) convert chemical energy into electricity through catabolic activities of exoelectrogenic bacteria under anaerobic conditions, and have a great self-sustainable potential of converting wastewater to electric power and a cost-effective approach for environmental sustainability. However, the performance is still far from the expected levels, and researchers continue to improve the performance of MFCs. Even though many different configurations are possible for the MFCs in either batch or continuous flow operation mode, MFCs in complete mix in batch mode configuration extensively studied in lab scale systems because of simplicity of construction and operation, where theoretically a uniform substrate concentration achieved in the systems. Recent studies confirmed that other rector configuration also succesfully can be applied into MFCs. One of them is Anaerobic Baffled Reactor (ABR) which is consisted of a series of vertical baffles to force the wastewater to flow under and over baffles as it passes from the inlet through outlet. Applying these reactors to MFC technology has a lot of potential for being developed into efficient applications. In this study, two types of MFCs configuration BPF-MFC and PF-MFC that simulate the existing wastewater treatment processes have been developed and compared in batch mode and continuous flow mode to investigate MFC performances. The results showed that the BPF-MFC has higher substrate removal than the PF-MFC. The maximum COD removals up to 88% and 74% were obtained with initial COD concentrations of 1000 mg/L in BPF-MFC and PF-MFC reactors, respectively. Moreover, when we compare the power generation in the both BPF-MFC and PF-MFC reactors, it is clearly shown that the BPF-MFC has better power density response under the same conditions. Therefore, this study showed that the flow pattern in the MFC reactors is one of the crucial factors that directly effects performances.