A novel nitrogen removal strategy, the combined photoelectrocatalytic oxidation and autotrophic biofilm denitrification, was developed to achieve simultaneous NH4+-N oxidation and NO3 -N reduction in a single reactor. Agl/TiO2-NTs and autotrophic denitrifying biofilm were used as anode and cathode, respectively. NH4+-N oxidation efficiency was enhanced by 3 times after the introduction of visible light. Moreover, NO3 -N and NO2 -N generated in the process of NH4+-N oxidation could be further removed by biocathode. Applied voltage and pH have significant effects on nitrogen removal. The NO3-N and NH4+-N removal efficiencies gradually increased from 27.2% to 74.3% and 60.0% to 83.1%, respectively, when the voltage increased from 1.0 V to 3.0 V. Neutral or slightly alkaline condition was favorable on account of the autotrophic denitrifying biofilm. The optimum TN (TN=NH4+-N + NO3 -N + NO2 -N) removal efficiency was up to 89.6% at pH 8 with 3.0 V voltage. (C) 2016 Elsevier Ltd. All rights reserved.