The performance of many processes such as sewage treatment plants is highly related to the oxygen transfer from air bubbles, usually injected through diffusers, to microorganisms able to degrade pollutants contained in wastewaters. However, characterizing accurately the oxygen mass transfer in such processes is still a challenging issue mainly because of the liquid phase complexity. The aim of this project is to develop specific techniques and rigorous models to better estimate the various mechanisms that locally govern the gas/liquid mass transfer process. New and efficient visualization techniques are proposed to visualize and estimate the surfactant migration, structure and layer thickness. A new modelisation will permit to adapt and reduce the energy consumption of aeration that represents 80% of the global process energy.