Experimental validation of a simulation and design model for nitrogen removal in sequencing batch reactors

Abstract

The development and the sensitivity analysis of a dynamic SBR simulation model for biological nitrogen removal, based on the Activated Sludge Model N. 1, are presented. An experimental study for the calibration and validation of the model was carried out using a bench scale SBR. Piggery wastewater was used as feed. The operating daily cycle of the SBR reactor included three sub-cycles of 7.5 hours each, each one alternating anoxic and aerobic condition, while settling phase was carried out at the end of the three sub-cycles. A first enhancement of model N. 1 was performed splitting nitrification into the two sub-processes of nitriation and nitratation. A second enhancement of the model was obtained with the introduction of a switch function of nitratation kinetics. An algorithm for optimization of the cycle length and phase distribution in order to minimize effluent nitrogen concentration was developed. A design procedure of SBR systems is also described.