Aeration Control with Gain Scheduling in a Full-scale Wastewater Treatment Plant

Abstract

Process control is important at wastewater treatment plants to meet effluent criteria and minimise resource use. In a nitrogen removal plant, the aeration costs in the biological treatment part constitute the largest single electricity user at the plant. This study has investigated gain scheduling PI control at the Käppala wastewater treatment plant in full-scale operation and by simulation using a calibrated model of the plant. The aim was to vary the controller settings based on the nitrogen removal performance to achieve an energy saving. The best results were reached when scheduling the controller output limit, achieving a higher energy saving compared to a controller without gain scheduling.