Optimization of the operation conditions for denitrifying wastewater treatment plants

NOELIA ALASINO; MIGUEL C. MUSSATI; NICOLÁS SCENNA

Barcelona, España

Simposio; 2nd European Modeling and Simulation Symposium EMSS2006 and International Mediterranean Modelling Multiconference I3M2006; 2006

Universitat Autònoma de Barcelona y Universitat Politècnica de Catalunya

Optimal operation condition for biological nitrogen removal and organic matter oxidation for selected wastewater treatment plant configurations in continuous operation was investigated. The optimization of each proposed configuration aims to minimize the total annual operation cost while predicting compliance with the effluent permitted limits. Defined influent wastewater flow and composition are assumed, and the plant equipment size is supposed given. Each configuration plant consists of five reaction compartments, tree of which are aerated and two anoxic, and a secondary settler. The Activated Sludge Model No. 3 and the Tákacs model are used to model the reaction compartments and the secondary settler, respectively, resulting in a highly nonlinear system. The three conventional plant configurations for biological nitrogen removal, i. e. predenitrification, postdenitrification and pre-postdenitrification systems are extended considering flow distribution of the nitrate and sludge recycle streams and fresh feed stream along the reaction zone. The resulting mathematical model is a Non-Linear-Programming problem. A reaction performance indicator is defined aiming to compare the different operation strategies obtained as optimal solution for each case.