Control strategies for removing nitrogen compounds in wastewater treatment plants

This paper presents the application of different control strategies applied for wastewater treatment plants (WWTP). The main purpose is to evaluate its effectiveness/cost trade-off attending a set of criteria. The study has been performed by using the Benchmark Simulation Model No. 2 (BSM2) and the evaluation criteria have been selected taking into account the most relevant indicators provided by this benchmark scenario. More specifically, five strategies have been implemented and compared with the default closed loop control strategy (DCL) of BSM2 and between them. Results show that the control strategies that use the ammonia cascade controller provide better results in most of the evaluated criteria than the control strategies implemented by using only the oxygen controller. Ammonia controller improves the results in terms of effluent quality and operational costs due to the reported aeration energy savings. As a conclusion of this study the control strategy that uses the ammonia and carbon controllers has been selected as the most recommended for implementation.