Study of Factors Controlling Nitrite Build-Up in Biological Processes for Water Nitrification

Nitrification processes are well known for certain problems in connection with transient build-up of nitrite ions. Moreover, some works have shown interest in controlling the build-up of this ion, particularly when treatment procedures for nitrogenous pollution are of the nitritation-denitritation type. With this in mind, we have carried out a programme of research to check the main factors responsible for the accumulation of this ion, i.e. [NH4]o, T°, pH, and dissolved O2. The main results highlight the key role played by the free form N-NH3 and by the temperature. This research thus provides answers to a number of practical questions and allows us to envisage setting up new procedures for the treatment of nitrogenous pollution by fixed cultures.