Abstract: The energy consumption analysis for the removal of ammonia and phosphorous is studied in a pilot-scale sequencing batch reactor (SBR) of 8.8 m³.Frequency converter is used to control ρ(DO) at the constant level to investigate the power consumption at aerobic stage and the amount of the additional carbon sources in different ρ(DO),temperatures and running ways.Results show that frequency converter can reduce the energy consumption of about 49.4% compared with the full load operation,when ρ(DO) is set to 2.0 mg·L^-1.The electricity consumption is negatively correlated with the temperature.Finally,the operation pattern of step-feeding can not only save the carbon source cost of 47.6%,but also reduce the energy consumption of 17.9%.