Abstract
This paper presents the mathematical model of the nitrification process starting from the kinetic equations describing this process. The mathematical model was developed using Scilab-Xcos program and allows the visualization in time of the water concentration evolution of the following parameters: organic nitrogen (Norg), ammonia nitrogen (NH3-N), nitrite nitrogen (NO2-N), nitrate nitrogen (NO3-N), oxygen (C) and biochemical oxygen consumption for the oxidation of organic substances containing carbon (LC). Also in this work is presented an example of simulation of the above mentioned parameters.