Without neglecting the purification performance aspect of the process, research activity is focused, among other things, on developing procedures for acclimatizing microorganisms (heterotrophic, autotrophic) to effluents (synthetic or real), with all the attendant complications due in part to the nature and concentration of toxic compounds, the importance of inhibition phenomena and stability problems. So the challenge is as much to understand biodegradation performance as it is to control the coupled process. The ultimate aim is to optimize the potential of biomass for biological degradation and achieve optimum membrane separation.

The intensification of transfer processes is also an integral part of the axis, in order to gain a better understanding of transfer mechanisms. These include - operating conditions in relation to local hydrodynamic problems (shear, stress) - the structure of biological flocs (in collaboration with the sludge rheology axis) - membrane clogging (proteins, humic acids, etc.) - material transfers, in order to gain a local understanding of fluid-particle-membrane interactions. Systemic modeling is also addressed, using, for example, the kinetic transfer models of Andrews-Haldane and Monod.

Finally, in-situ biological activities are also studied, either through a simplified system in which biological activity is minimal (endogenous respiration), or through a complex system in which activity is maximal (exogenous respiration).