Nitrifying activity monitoring and kinetic parameters determination in a biofilm airlift reactor by respirometry

Abstract

The applicability of batch respirometry, as a simple technique for monitoring off-line nitrifying activity and kinetic parameters, was evaluated using two sets of ammonia and nitrite concentrations. The O2 uptake rate (OUR) profiles obtained from the assays were adjusted to a substrate inhibition model. The maximum specific ammonia-oxidizing biomass activity (rSmax) was 0.079 g N-NH4+ g VSS−1 d−1 with a half saturation coefficient (KS) of 11 mg N-NH4+ l−1 and an inhibition coefficient (Ki) of 3300 mg N-NH4+ l−1. Besides, the maximum specific value of nitrite-oxidizing activity was 0.082 g N-NO2− g VSS−1 d−1 with a KS of 4.1 mg N-NO2− l−1 and Ki of 1400 mg N-NO2− l−1.