Continuous autotrophic denitrification process for treating ammonium-rich leachate wastewater in bioelectrochemical denitrification system (BEDS)

The reduction of nitrogen compounds in aqueous solution is extremely important for sustainable management of ecosystem and human health. An autotrophic bioelectrochemical denitrification (BED) process was evaluated at various conditions for enhanced treatment of synthetic wastewater (SW) and ammonium-rich leachate. With SW, a decrease in hydraulic retention time (HRT: 41.6 to 8.3 h) resulted in a 370% increase in denitrification rate from 0.026 to 0.096 kg NO3--N/m(3). D. An increase in applied voltage (0.7 to 2 V) enhanced nitrate removal (81 to 97% removal), but coulombic efficiency decreased from 74% to 19%. With doubled cathode electrodes, the nitrate removal rate was doubled from 0.056 to 0.114 kg NO3--N/m(3). D. Moreover, leachate wastewater was successfully denitrified with the maximum removal rate of 0.121 kg NO3--N/m(3). D. These results point towards the practical potential for the combination of nitrification systems with BEDS for reduction of nitrogen for discharge purposes. (C) 2019 Elsevier B.V. All rights reserved.