Anodic potentials, electricity generation and bacterial community as affected by plant roots in sediment microbial fuel cell: Effects of anode locations

A planted sediment microbial fuel cell (PSMFC) is a promising new technology for harvesting energy and remediating a contaminated geo-environment. In this study, the effects of roots (of Acorus tatarinowii) on oxygen profiles in sediment, power generation, and anodic bacterial community were investigated in PSMFCs and unplanted SMFCs with different anode locations to roots. The presence of plant did not improve the electricity generation when roots were placed on the surface of an anode because a high amount of oxygen loss from roots increased the redox potential at anode and made aerobic bacteria co-exit and compete with electrochemically active bacteria in substance utilization. It was suggested to place the anode under the roots with a proper distance, where the PSMFCs made use of root-derived organics, avoiding the negative effects of oxygen loss. Oxygen loss could control the diurnal rhythm of power generation in the PSMFCs. [Display omitted] •The root location to the anode influenced the electricity generation.•Aerobic bacteria co-exited with EAB on the anode with the presence of roots.•Oxygen loss influenced the diurnal rhythm of power generation in the PSMFCs.