For the disposal of mineral oil on surface water and sewage systems, most governments have special requirements on the quality of wastewater. The Dutch disposal resolution for example allows a maximum concentration of 20 mg/l mineral oil, and 100 mg/l unresolved particles.

By means of a water-oil separator, a large amount of oil can be removed from the wastewater. However, chemically stabilized oil/water solutions should be managed in an appropriate manner. These solutions can be purified by means of membrane filtration. (Ultra Filtration) To remove the organic compounds that remain in the permeate, ozone can be used. Research shows that pre-treatment with ozone make reuse of the UF permeate as process water possible. [1]

[1] In-Soung Chang, Chang-Mo Chung, Seung-Ho Han, Treatment of oily wastewater by ultrafiltration and ozone. Taejon, South Korea 2000