Optimization and control of aeration distribution in the wwtp nitrification reactor

Abstract

The aerated biological reactor of the Waste Water Treatment Plant (WWTP), operating on the basis of the active sludge technology, is recognized as the major energy consumer of the WWTP. Automatic control of the nitrification treatment step plays a major role both for satisfying the required quality of the effluent water and for whole plant energy efficiency. The paper presents a solution for finding the optimal distribution of aeration along the nitrification reactor, in association to ammonia automatic control. The incentives of the proposed nitrification control approach are investigated by two control system structures. They have the ammonia master controller acting either on the setpoints of the Dissolved Oxygen controllers, in a supervisory control design, or manipulating the air flow rate along the reactor by the Dissolved Oxygen slave controllers, in a cascade setup. Investigations were performed for an Anaerobic-Anoxic-Oxic municipal WWTP case study. The benefits of the proposed control structures are revealed by assessing the Pumping Energy, Aeration Energy and Effluent Quality performance indices.