The pollution level of the marine environment, landlocked seas in particular, has made it necessary to search for more effective techniques and technologies of limiting pollution generated by ships. Further elimination of oil pollution in dumping waters has been focused on in the recent period. Oil dumped in bilge waters is estimated to have a significant 20% share in the total amount of oil getting into the seas. This fact settles the issue of the important role bilge water separators on ships. The content of oil pollution in dumping waters can be restricted to even below 5 ppm, supporting traditional deoil-ing systems with ultrafiltration techniques. On the basis of research conducted, possibilities of restricting pollution in depending waters have been shown, depending on the kind of membranes applied.