The startup and performance of the completely autotrophic nitrogen removal over nitrite (CANON) process was tested in a continuously fed granular bubble column reactor (BCR) with two different aeration strategies: controlling the oxygen volumetric flow and oxygen concentration. During the startup with the control of oxygen volumetric flow, the air volume was adjusted to 60 mL/h and the CANON reactor had volumetric N loadings ranging from 7.35 to 100.90 mgN/L d with 36-71% total nitrogen removal and high instability. In the second stage, the reactor was operated at oxygen concentrations of 0.6, 0.4 and 0.2 mg/L. The best condition was 0.2 mgO(2)/L with a total nitrogen removal of 75.36% with a CANON reactor activity of 0.1149 gN/gVVS d and high stability. The feasibility and effectiveness of CANON processes with oxygen control was demonstrated, showing an alternative design tool for efficiently removing nitrogen species. (C) 2015 Elsevier Ltd. All rights reserved.