Abstract
In the present study, nitrifying bacteria entrapped in waterborne polyurethane gel was used to investigate the kinetic characteristics of nitritation and nitratation in relation to achieve shortcut nitrification. The nitrite accumulation rate was over 80% during the acclimation period. The following kinetic parameters were experimentally obtained: maximum nitrification rate (v(max)), half-saturation coefficient (K(s) and K(o)), and inhibition coefficient (K(IH)). The bacterial populations were also determined by fluorescence in situ hybridization. 73.5% proportion of ammonia oxidizing bacteria (AOB) resulted in a significantly higher ammonia oxidizing rate than nitrite oxidizing rate, which is in agreement with higher V(max) of nitritation (608.5 mgNl(-1)-pellet h(-1)) over nitratation (66.3 mgN l(-1)-pellet h(-1)).
