Simulation numérique des réacteurs gaz-liquide utilisés en traitement de l'eau

The main objective in water industry is to ensure the adequate treatment process, guarantee its maximum efficiency and contain investment and operating costs. Due to the increasing power of computers, Computational Fluid Dynamics modelling approach becomes an efficient tool to reach this objective. This paper resumes some applications of the CFD modelling to the study of the hydrodynamic and mass transfer performance of single- and multi-phase biological and/or chemical reactors used in water and wastewater treatment. Numerical simulations together with experimental measurements have been performed on laboratory and full-scale plants in order to gain better understanding of the physical phenomena (mixing, interfacial transfer) occurring in these systems in order to improve their design and process efficiency. The examples described in this paper allow to highlight the feasibility and provisional limitations of the CFD modelling tools. In most of the cases complementary work is necessary to be carried out in order to improve the mathematical models related basically to a better knowledge of the physical parameters controlling the hydrodynamics of the reactors.