Event-based control for dissolved oxygen and nitrogen in wastewater treatment plants

This paper addresses the problem of basic control loops in wastewater treatment plants. By basic control loops we are referring to the traditional dissolved oxygen and nitrates. In a usual activated sludge process based wastewater treatment plant, these controls are located, respectively, at the aerated and anoxic sections. They are the basic controls more sophisticated control solutions can be based upon. Therefore it is important that these loops perform in an efficient way. The problem is addressed here within the framework provided by the Benchmark Simulation Model Number 1 (BSMI) and by the use of an event-based solution. As far as to the knowledge of the authors, no solution based on this kind of controllers has been proposed already in the literature. The controllers are taken as of similar complexity as the ones provided as default control strategy in the BSMI, therefor being the main difference, the possibilities provided by the event-based implementation. It will be verified that the solution can slightly improve the performance of the already exiting controllers both at loop level as well as at plant operation level.