Performance of cathodic nitrate reduction driven by electricity generated from ANAMMOX sludge in anode

Abstract In this study, ANAMMOX sludge was used as anode microbial catalysts to drive electrocatalytic reduction of nitrate in the SnCu-Pd/CFC catalytic cathode with total nitrogen (TN) removal efficiency of ANAMMOX as well as generate electricity without additional carbon and energy source. The system operation with 1.74 Kg·N/m3·d as nitrogen loading rate (NLR) exhibited a TN removal efficiency of 96.3% and obtained the highest nitrogen removal rate (NRR, 1.69 Kg·N/m3·d), increased by 14.9% and 0.30 Kg·N/m3·d compared with open circuit (control group), respectively. Maximum voltage (39.8 mV) and power density (21.20 ± 0.05 mW/m3, standardized to anode surface area) were also observed. Additionally, microbial community analysis revealed community structure of S2anode had an obvious disparity compared with others as the predominant ANAMMOX bacteria (AnAOB) closed to anode surface was evolved from Candidatus_Kuenenia to Candidatus_Brocadia.