The objective of this research was to investigate the macroscopical effect of high concentration nitrite and nitrate denitrification on waste decomposition and to evaluate the kinetics of NO(3)(-)-N and NO(2)(-)-N removal. Two reactors loaded fresh refuse were fed 4000 mg NO(3)(-)-N/L or 4000 NO(2)(-)-N/L every 48 h, respectively. Results showed that NO(3)(-)-N addition was more effective on promotion of the waste degradation process as compared to NO(2)(-)-N addition. In the initial stage, NO(x)(-)-N removal was mainly contributed by adsorption rather than denitrification. NO(x)(-)-N reduction rate data obtained from microcosm experiment were fit to Monod kinetics, with specific removal rates of 1.625 mg NO(3)(-)-N/(g dry waste d) and 1.125 mg NO(2)(-)-N/(g dry waste d) and nitrogen removal half-saturation constants of 1250.5 NO(3)(-)-N/L and 125.5 NO(2)(-)-N/L, respectively. (C) 2008 Elsevier Ltd. All rights reserved.