Dissolved Oxygen Tracking and Control of Blowers at Fast Time Scale

Abstract Aeration is very important and expensive process in Wastewater Treatment Plant (WWTP). Oxygen is provided as a fundamental component for the biological processes. The aeration system is a complicated hybrid nonlinear dynamic system with faster dynamics compared to internal dynamics of the dissolved oxygen (DO) at the biological reactor. The currently used control systems are far from satisfactory. The achieved energy cost due to blowing the air into the biological reactor aerobic zones is high and the (DO) tracking performance is low. This paper extends newly developed hierarchical hybrid model predictive controller to plants with several aerobic zones supplied by an aeration system of limited capacity. The constraint on the airflow that can be delivered is then active and a multivariable predictive controller at the upper level handles its distribution between the zones. Simulation tests for aeration system at WWTP in Kartuzy are presented.