This paper is focused on modelling the degradation of micropollutants by solar photo-Fenton at pilot plan scale. To this aim, a three pesticide mixture (acetamiprid, thiabendazole and imazalil, 100 μg l-1 each) was treated by photo-Fenton in simulated secondary effluent. The model covered a wide interval of catalyst concentration (1 to 20 mg l-1 Fe) and solar irradiance (5 to 30 W m-2). A Monte Carlo direct search was used to determine the kinetic constants which adjusted pesticide removal and hydrogen peroxide consumption in the selected experimental conditions (identification runs). The model was validated with experimental conditions different from the identification step (validation runs). Hydrogen peroxide consumption and pollutant degradation could be predicted adequately for all irradiances and iron concentrations higher than 5 mg l-1 Fe. As a result, the presented model could predict the treatment time during the whole year, as it is valid for a wide range of irradiation and for commonly used values of catalyst concentration.