Reduction of aeration costs by tuning a multi-set point on/off controller: A case study

The objective of this work was to select the best configuration for a dissolved oxygen multi-set point on/off controller of a full-scale wastewater treatment plant to ensure the best dissolved oxygen concentration set-point values. The optimal set point values should allow the attainment of a good quality of effluent wastewater and minimise the operational costs related to the aeration process. To achieve this goal, simulation and optimisation software and off-line optimisation techniques were used. As a result of the optimisation of the dissolved oxygen controller, a more stable system was obtained. Because of the stability of the system, the quality of the effluent and activated sludge and the operating life of the aeration equipment was increased. Moreover, the aeration costs were reduced by approximately 17%.