Nitrification modelling in biofilms under inhibitory conditions.

A biofilm model has been developed for simulating nitrification in biofilms under inhibitory conditions. Nitrification inhibition has been modelled using uncompetitive inhibition kinetics. Inhibition kinetic experiments were performed by varying the bulk concentrations of inhibitory compound, aniline. Two sets of results were obtained with a nitrifying biofilm that was unacclimated to aniline and another which was acclimated to aniline. Fitting of the nitrification inhibition biofilm model to the experimental results yielded the nitrification inhibition constant, Ki, for aniline. Both the experiments yielded a value of about 3mg/L for Ki, which was similar to that obtained during nitrification inhibition experiments with suspended growth process carried out in an earlier study. The nitrification inhibition biofilm model is general and can be applied to nitrification inhibition with other toxic compounds.