Oily Water Separator

Required for MARPOL compliance, an oily water separator (OWS) (marine) is a piece of equipment specific to the shipping or marine industry. It is used to separate oil and water mixtures into their separate components. This page deals exclusively oily water separators aboard marine vessels. They are found on board ships where they are used to separate oil from oily waste water such as bilge water before the waste water is discharged into the environment. These discharges of waste water must comply with the requirements laid out in Marpol For information on more general oil water separators Oily Water Separators (general).

Bilge water is a near-unavoidable product of shipboard operations. Oil leaks from running machinery such as diesel generators, air compressors, and the main propulsion engine. Modern OWSs have alarms and automatic closure devices which are activated when the oil storage content of the waste water exceeds a certain limit.