Water that collects in a ship’s bilges and often becomes dirty and toxic. Bilge water also includes liquids from machinery spaces, internal drainage systems, sludge tanks and various other sources. This mixture is collected in the bilge water holding tank, which is usually kept at a high temperature. Bilge water, regardless of its source, must be treated to reduce the oil content to levels that comply with international regulations for release into the environment.
Note : Cleaning agents, emulsifiers, solvents, or surfactants used for cleaning can cause the bilge water to emulsify. Appropriate measures should be taken to minimize the presence of these substances in a ship’s bilges.