Performance investigation of multi-anode-shared cathode microbial fuel cells with different anodic internal configurations

Scaling up microbial fuel cells for practical applications is a challenge in wastewater treatment. MFC internal fluid flow is an important aspect to consider as it influences the bio-electrochemical reactions occurring at the electrodes. To investigate the influence of internal fluid flow on the bio-electrochemical efficiency of a MFC, vertically disposed multi-anode-shared cathode MFCs were developed to study the performance differences from two-fluid flow types which varied according to the characteristics of the internal structure of the anode chamber. The multi-anode plug flow MFC (MAPF-MFC) with a rectangular-type internal structure and the multi-anode MFC (MA-MFC) with no internal structure in the anode chamber (standard) were tested under varying organic loads and hydraulic loads. The multi-anode plug flow MFC on average produced 1.2 × higher power density except under varying flow rates, 1.3 × higher current over time, 1.21 × higher COD removal efficiency, 2.05 × higher removal rate, and 1.5 × higher coulombic efficiency than the MA-MFC. The multi-anode plug flow MFC also achieved complete COD degradation 24–96 h faster than the MA-MFC. Ammonium-N and Total Nitrogen removal were treated at a higher efficiency in the multi-anode plug flow MFC. This study demonstrated that the design of the internal structure of the anode chamber is key to enhancing MFC performance in wastewater treatment and power generation and with the addition of a shared cathode, this MFC has the potential to increase volumes treated, saving time and operation costs. Graphical abstract