The variability observed in the experimental sets is reflected inthe model. Changes in the bacterial growth parameters, includingmaximum denitrification rate (VDRmax) and Kxhave a great impacton the denitrification performance and the initial lag phase. Theseresults concur with the data reported in literature were a change inthe bacteria population can increase or collapse the denitrificationrates. The denitrification rates can vary from 0 to 170 g (m3-d)−1or more, depending on the bacterial species and strain (Gomezet al., 2003; Patureau et al., 2000).