Enhanced simultaneous nitrification/denitrification in the biocathode of a microbial fuel cell fed with cyanobacteria solution

A double-chamber microbial fuel cell (MFC) fed with the decomposed cyanobacteria solution at both the anodic and the cathodic compartments was constructed to investigate the power generation and the nitrogen removal performance in the cathode. The simultaneous nitrification and denitrification (SND) could be achieved effectively when 800-1000 mg L-1 chemical oxygen demand (COD) and 5.0 +/- 0.3 mg L-1 dissolved oxygen (DO) were applied to the cathode. The achieved removal efficiencies of 0.064 +/- 0.005 kg TN m(-3) day(-1) and 0.063 +/- 0.005 kg NH4+-N m(-3) day(-1) under the closed-circuit condition were 2.6 and 2.0 times greater than that under the open-circuit condition, respectively, which indicated the capability of the MFC system to improve the nitrogen removal performance in the cathode. Both the enrichment of the heterotrophic denitrifying bacteria with the organic matter added in the cathode and the stimulated metabolic activities of the nitrifiers and denitrifiers in the electric field probably contributed to the observed enhanced nitrogen removal efficiencies in the MFC system. Therefore, MFC is expected to be a promising approach for efficient nitrogen removal accompanied with power generation in the cathode under high organic matter loading condition. (C) 2015 Elsevier Ltd. All rights reserved.