Performance assessment of cascade control strategy in wastewater treatment process

As the public awareness of environmental protection increases and the environmental regulations become more stringent, effective control of the wastewater treatment process (WWTP) has become a research hotspot. In this paper, a cascade MPC and PID control strategy is introduced to the Benchmark Simulation Model 1 (BSM1). The proposed cascade control structure is composed of a primary MPC controller to control the nitrate concentration in the effluent and a secondary PID controller to control the nitrate concentration in the final anoxic compartment. The suggested method controls the nitrate concentrations in the effluent as well as in the final anoxic reactor simultaneously to strictly satisfy the quality of the effluent as well as to remove the effects of disturbances more quickly by manipulating the external carbon dosage. Because the control performance assessment (CPA) technique has the features of determining the capability of the current controller and locating the best achievable performance, the other novelty of this paper is to take the CPA technology into the wastewater treatment process. The CPA results indicate that the primary MPC controller has more potential to improve compared with the secondary PID controller.