Decentralized Model Predictive Control for N and P removal in wastewater treatment plants

Due to the complex and non linear character, wastewater treatment process is difficult to be controlled. And the demand for removing the pollutant, especially for nitrogen (N) and phosphorus (P), as well as reducing the cost of wastewater treatment plant (WWTP) is an important research topic. This paper applies PI control and decentralised model predictive control control to the combined phosphorus removal Benchmark Simulation Model 1 (BSM1-P) wastewater treatment process to enhance the P removal. A default control strategy which contains two control loops and is similar to the one given by the original version of BSM1 was tested on BSM1-P. In addition, linear models have been identified and model predictive controllers implemented for each one of these loops. The simulation results showed that the MPC controllers are able to the controller performance in all the three weather conditions.