A model of nitrogen removal from waste water in a fixed bed reactor using simultaneous nitrification and denitrification (SND)

A model predicting the effluent nitrogen concentration of treated waste water in an submerged fixed bed reactor using clinoptilolite clay as matrix, is presented. By this treatment oxidation of organic material, nitrification and denitrification, by three different classes of bacteria, occurs in the same environment. The occurrence of these three processes within a close environment resemble too some extent the way the processes take place in aquatic sediment, which also to some extent consists of clay. The results presented in this paper show that it is possible to simulate the simultaneous nitrification and denitrification (SND) processes with a model which containing 6 state-variables including a coupling of the 3 processes performed by each of the bacterial species included. The model results and the results obtained from experimental data are in general comparable.