Increased power production from a sediment microbial fuel cell with a rotating cathode.

The application of a rotating cathode in a river sediment microbial fuel cell increased the oxygen availability to the cathode, and therefore improved the cathode reaction rate, resulting in a higher power production (49 mW/m(2)) compared to a nonrotating cathode system (29 mW/m(2)). The increased dissolved oxygen in the water of our lab-scale sediment MFC, however, resulted in a less negative anode potential and a higher anodic charge transfer resistance, which constrained the maximum power density. Thus, an optimum balance between the superior cathode reaction rates and the inferior anode reaction rates due to higher dissolved oxygen levels must be ascertained.