Control strategies for ammonia violations removal in BSM1 for dry, rain and storm weather conditions

This paper presents a proposal with the objective of eliminating violations of ammonia nitrogen in the effluent (NH_e) of a wastewater treatment process. Furthermore, improving effluent quality and reducing operating costs and the percentage of violations of total nitrogen in the effluent (N_tot,e) are also considered. The evaluation of control strategies are conducted with the Benchmark Simulation Model N^o 1 (BSM1). Several controllers have been proposed: Model Predictive Control (MPC) with inlet flow rate feedforward compensation (MPCFF), Fuzzy controller and Exponential, Linear and Affine Functions. MPCFF and Fuzzy controller are applied in a hierarchical structure to improve effluent quality, to reduce operational costs and to decrease NHe peaks. Exponential, Linear and Affine Functions are implemented, along with the hierarchical control structure, to avoid NH_e violations. The results are presented and compared with the default control strategy of BSM1 for dry, rain and storm weahter conditions. They show that the NH_e violation removal is achieved for the three weather conditions. For dry influent also an improvement of effluent quality and a reduction of operational cost are acquired. For the rain and storm cases, an increment of operational cost is required.