Scaled-up multi-anode shared cathode microbial fuel cell for simultaneous treatment of multiple real wastewaters and power generation

Abstract

Microbial fuel cell (MFC) is lauded for its capacity to valorize organic substrates in wastes, providing a solution to environmental pollution and energy crisis. While different types of organic substrates affect removal efficiency and current output, most MFCs are designed to only be able to utilize one type of wastewater. However, many real wastewater treatment sites generate more than one type of wastewater which hinders the installation of most MFCs. This study aimed to investigate the performance of the novel-designed multi-anode shared cathode MFC (MASC-MFC) compared with a standard single anode/cathode MFC (SAC-MFC) and the simultaneous treatment of different types of real wastewaters (sewage, slaughterhouse, and hospital) in one MFC unit. The MASC-MFC (9025 mW/m2 at 23.332 mA/m2) produced 1.7 times and 1.6 times higher in power density and current density and 2.2 times lower in internal resistance than the standard single anode/cathode MFC (SAC-MFC). A maximum COD removal efficiency of 62.7% was achieved with synthetic wastewater. Feeding the MASC-MFC with multiple real wastewaters decreased maximum power density 3.5 (2599 mW/m2) times and increased internal resistance 2.7 times. Stable current generation 1.575 mA was achieved over 300 h despite the different and complex wastewater physio-chemical compositions. The MASC-MFC achieved over 40% and approximately 30% coulombic efficiency independently in all the anode chambers irrespective of the type of real wastewater used, demonstrating the MASC-MFC's capacity to treat different real wastewaters with the added benefit of electricity production.