Nitrification and denitrification in two-chamber microbial fuel cells for treatment of wastewater containing high concentrations of ammonia nitrogen

Simultaneous nitrification and denitrification in the aerated cathode chamber of microbial fuel cells (MFCs) inoculated with nitrifying bacteria were investigated using two-chamber MFCs. Based on the variations of [GRAPHICS] , [GRAPHICS] and [GRAPHICS] in the cathode chamber of four MFCs added with different concentrations of [GRAPHICS] (50, 65, 130 and 230 mg/L), the occurrence of simultaneous nitrification and denitrification leading to effective removal of nitrogen was confirmed. Electrochemical reaction with electrons transferred from the anode chamber was found to be the major mechanism responsible for the removal of [GRAPHICS] in the cathode chamber. The estimated values of the first-order rate constant for nitrification and denitrification varied in the range of 0.3-1.7 day(-1) and 0.2-0.9 day(-1), revealing a decreasing trend with increases in the initial [GRAPHICS] concentrations and the detected maximum concentration of the nitrification product of [GRAPHICS] in the cathode chamber, respectively.