Analysis of phosphorus removal performances in a municipal treatment plant

This paper addresses the performance modeling and analysis in the case of a wastewater treatment system for removal of phosphorus, consisting a biological reactor and a secondary settling tank. The mathematical model was developed in the SIMBA simulation environment. The system is based on an actual municipal wastewater treatment plant. The implemented architecture is similar to that in BSM1 (the digestion anaerobic process is not treated) so that the Activated Sludge Model 2d is used to describe the variables and processes of the wastewater treatment plant. The control strategies were simulated, using the model of an influent having loads corresponding to the real plant, for a dry regime, in open and closed loop. As part of the analyzed strategies, PI-type regulators were used for the control of dissolved oxygen concentration, internal recirculation and ferric chloride addition, which accelerates the phosphorus precipitation.