Bilge water
Bilge water is water drained from vessel decks or machinery spaces that may have come into contact with oil. It is comprised of oil, detergents, liquids from the engine room, and other toxic chemicals, bilgewater collects in the bottom of the vessel before being stored in bilge tanks. A single ship can produce several tonnes of this oily mixture in a single day (Onwuegbuchunam et al., 2017)
The bilge water composition and volume varies from day to day and from ship to ship depending on the routines onboard, daily activities, trading area and what type of equipment is installed in the engine room.
United States of Environmental Protection Agency “Oily Bilgewater Separators.” n.d. https://www3.epa.gov/npdes/pubs/vgp_bilge.pdf
Onwuegbuchunam, D.E., Ebe, T.E., Okoroji, L.I., Essien, A.E., 2017. An analysis of ship-source marine pollution in Nigeria seaports. J Mar Sci Eng 5. https://doi.org/10.3390/JMSE5030039