A dynamic model for the degradation of aqueous metronidazole by hydrogen peroxide and ultraviolet irradiation processes (UV/H2O2) as an advanced oxidation technology (AOT) in a single lamp tubular photoreactor as well as in a multilamp tubular photoreactor is developed. The model contains the main chemical and photochemical reactions in a medium flowing in the turbulent regime. The optimal hydrogen peroxide concentrations of 75, 150, and 200 mg L−1 were predicted for different alkalinity concentrations of 0, 1.5, and 3 μM, respectively. The model is validated with distilled water as well as alkaline water at different alkalinity concentrations. The model is validated by using the experimental data reported in the open literature. The velocity field and concentration profiles for the turbulent flow using the k−ε model are determined by computational fluid dynamics (CFD).