Anodic current distribution in a liter-scale microbial fuel cell with electrode arrays

A liter-scale microbial fuel cell with graphite rod electrode arrays (MFC-EA) was constructed and its relative anodic current distribution was investigated with 9 groups of anode electrodes. Meanwhile, the influences of COD concentration and ionic strength of anolyte on anodic current distribution were discussed. It is demonstrated that the electrode spacing between the anode segment and cathode significantly influenced the ohmic resistance distribution and the biomass content of each segment, further affected the anodic current distribution. A significantly uneven current distribution was found in MFC-EA, especially at high currents. The further the anode segment was away from the cathode, the smaller the segment current generation contributed to the total current. Consequently, a suitable MFC structure with equidistant electrode spacing will be a necessary consideration for large-scale MFC design. Moreover, for MFC-EA, improvement on the uneven current distribution was achieved by feeding the anolyte with a COD concentration of 1000 mg COD L−1 or with 0.2 M KCl.