Model Predictive Controller for Integrated Wastewater Treatment System

Abstract

Optimising control of wastewater treatment systems (WWTS), allowing for cost savings while fulfilling the effluent discharge limits over long period requires application of advanced control techniques. Model Predictive Control (MPC) is a very suitable control technology for a synthesis such a truly multivariable controller that can handle constraints and accommodate model-based knowledge combined with hard measurements. A hierarchical architecture is used to structure the MPC controller into the functional Supervisory, Optimising and Follow up levels. The Optimising Control Level is further decomposed into three layers operating in different time scales: slow, medium and fast. The paper considers MPC controller operating in medium time scale.As it is impossible to efficiently control the plant under all possible influent conditions, three dedicated control strategies were designed. The controller performance was validated by simulation based on Kartuzy WWTS data records. Recently developed mechanism for soft switching between different MPC control strategies was used in the simulations.