Design, implementation and experimental validation of a real-time control architecture for nitrogen removal in SBR systems

This paper presents a real-time control architecture for SBR systems with no holding tank. The control approach has been divided into three separated layers in order to accommodate different full-scale scenarios. The lower control layer processes the ORP and DO trajectories to detect the depletion of the denitrification and nitrification reactions in order to automatically interrupt the reaction phases. The intermediate layer has been designed to maintain the total solid mass constant in reactors. Finally, an ammonia controller has been implemented in the supervisory layer that optimises the aeration costs to fulfil the effluent ammonia requirements. The overall control system has been verified experimentally in a 150L pilot plant. In this study, the lower control layer reduced the length of mixing and aeration by approximately 20%. In addition, the experimental validation of the ammonia controller led to reductions of about 30% in the overall aerated fraction.