Abstract: An optimization control scheme for pre-denitrification type of biological treatment process for wastewater is proposed to achieve the wastewater effluent standards with minimal energy consumption control scheme.Complex mechanism and multitudinous parameters in wastewater biological treatment process make it difficult to solve this optimization problem.Based on international evaluation benchmark and activated sludge model No.1,a simplified process model is developed which is able to approximate the intrinsic model effectively.A hybrid genetic algorithm is proposed to look for the optimal value,and it raises the solution efficiency significantly.Simulation experiments validate the effectiveness of the proposed control scheme and method.