A 15 ppm bilge separator is a device used on ships to separate oil and contaminants from bilge water before it is discharged into the sea. The purpose of a bilge separator is to ensure that the oil content in the discharged water meets environmental regulations set by the International Maritime Organization (IMO). Typically, ships must comply with a 15 ppm oil content limit in bilge water discharged into the sea. Bilge separators work by employing physical and chemical separation methods to remove oil from bilge water before it is discharged into the sea. This helps prevent marine pollution and keeps the marine environment clean.