A STRATEGY TO SCALE-UP NITRIFICATION PROCESSES WITH IMMOBILIZED CELLS OF NITROSOMONAS-EUROPAEA AND NITROBACTER-AGILIS

A scale-up strategy for a nitrification process with immobilized cells is presented. The complete description of such a process for a wide range of conditions is time consuming or even impossible. For a successful scale up of the process knowledge of the rate-limiting step is essential. To estimate the rate-limiting step a regime analysis was used. A new element in this regime analysis is a solid third phase in which cells grow non-homogeneously. Three different conditions of the nitrification process were considered: low temperature (7-degrees-C) with a low ammonia concentration (2 mM), and optimal temperature (30-degrees-C) with an ammonia concentration Of 2 and 250 mM. The regime analysis proved to be a helpful tool for the understanding of the process and for establishing the rate-limiting step. A set of design rules for the different nitrification conditions was obtained from the results of this regime analysis.