A Modified ASM3 Model for a Trickling Filter

Abstract

This paper aims to determine and analyze a model for a biological filter that is part of an intensive recycled aquaculture plant. The biological filter used in this plant is a biofilm filter of trickling type. In this filter only the nitrification processes take place. In order to determine a model that can be used in real-time control a global model for the nitrification filter is recommended. Consequently, a modified ASM3 (Activated Sludge Model No. 3) model is proposed in order to include only the nitrification processes and to consider the nitrite and the nitrate as distinct statevariables. In this model the quality variables are the ammonium and the nitrite concentrations, the command variables are the aeration and recycled volume and the disturbance variable is the ammonium concentration from the fish tanks. The simulation results of the model are also presented in the paper. These results are obtained for different functioning conditions of the technological plant. The simulation results show that the model offers a good description of the main state variables: ammonium, nitrite and nitrate.