Abstract: A deck drainage system for removing oil containing fluid from an offshore facility includes a plurality of drains communicating with a liquid seal strainer for preventing a back flow of gas through the drain assembly. The liquid seal strainer is provided at each deck of the offshore facility with a vent provided downstream of the liquid seal strainers but upstream of a further treatment of the collected rain water and oil containing fluid. Preferably, the collected fluid is passed through a skim pile where oil is separated from the water and recovered. The clean water is then passed directly into the body of water beneath or adjacent the offshore platform. The vent located downstream of the liquid seal strainers but upstream of the skim pile preferably is provided with a flame arrestor for preventing a flash back of an inadvertent flame to the liquid seal strainer.

Abstract: Oil is recovered from an oil containing fluid mixture ecologically acceptable fluid is disposed of in a water body through the use of an open ended skim pile disposed in the water body and an interconnected skimmer vessel where fluid is maintained at a level independent of the mean level of the water body.