Comparison and combination of titrimetric and respirometric techniques to estimate nitrification kinetics parameters

A respirometric technique (open respirometry) and a titrimetric technique ( pH-stat) were compared to monitor the first, nitrification step (ammonia ox idation to nitrite) by providing a titrimetric biosensor (ANITA), previousl y developed to measure ammonia oxidation kinetics. with an oxygen electrode . Then, a new procedure for the simultaneous estimation of kinetic constant s related to both ammonia and nitrite oxidisers which couples both open res piration and titration. is presented. This procedure allows for the complet e characterisation of the nitrifying biomass kinetics with simple and short (1 to 1.5 h) tests without any analytical substrate determination. All dat a handling was implemented on Excel data sheets in order to be able to foll ow data inrerpolation step by step instead of using software packages which automatically perform data processing.