The aim of the research was to understand the membrane/surfactant interactions according to the hydrodynamic conditions. Surfactants from degreasing baths were used for the present study, and the microfiltration membranes were characterised by pore sire distribution. An anionic surfactant concentration below the critical micellar concentration and a nonionic surfactant solution temperature below the cloud point were chosen to provide maximum interactions with the membrane.