Inhibition kinetics of a commercial mixed culture by ammonium sulfate

The inhibitory effect of ammonium sulfate on a commercial mixed culture, used in biological waste-water treatment was studied under aerobic batch conditions. Several mathematical models of enzyme and growth kinetics including a death factor were analyzed through nonlinear regression to find the best fit to corresponding data of inhibition. The best fit model was found to be the generalized Monod type with a death factor having the biokinetic parameters; mu (max) 0.681 h(-1), K-s 0.224 gdm(-3), K-i 56240 g dm(-3), K 0.055 g dm(-3) and k(d) 0.052 h(-1) to represent the experimental data accurately. The low saturation coefficient value along with high maximum specific growth rate and inhibition coefficient denotes the competitive characteristics of commercial mixed cultures in the biological treatment of high ammonium polluted waste waters. (C) 2001 Elsevier Science B.V. All rights reserved.