About bilge water treatment

Oil pollution at sea has been a hot topic for decades. There have been too many unfortunate incidents that led to disastrous consequences to the environment but these unfortunate incidents also led to a very strict legislation when it comes to oil spills and handling of bilges from ships.

source: google.com

What is bilge water? It is water that collects in the lowest parts of the ship. On cruise ships this is mostly condensation water mixed with minimal quantities of oil that might leak from machines, during repairs, grease etc.

What do we do with it?ย The law (MARPOL) prohibits any discharges of untreated bilge water so, we treat it using Oily Water Separators.

Oily Water Separator (source: marinfloc.com)

How does the treatment work? The water gets separated from the oil and while we keep the oil residue in tanks onboard until we will land it shoreside using trucks, the clean bilge water gets discharged, as per MARPOL, through a special equipment called the White box that measures continuously the oil ppm (parts per million) in the water. MARPOL requires the clean bilge to be less than 15ppm when it goes overboard. Most cruise ships such as Royal Caribbean go above and beyond and have the limit set to 5ppm for the clean bilge. You can read more about it on their corporate website here.

White Box model (Source: marinfloc.com)

What does this have to do with me? A lot! Bilge treatment and disposal is one of my top priorities when I am onboard. Every week we are required to conduct several tests on both Oily Water Separators and Whitebox unit. These tests and inspections are done as per manufacturers instructions and they help us determine if the equipment is working properly or not. If any of these tests is not successful, then the operation is cancelled and shoreside specialized technicians are called onboard. Under normal circumstances, a ship is required to be able to hold its bilges for several days to weeks as long as it does not affect its stability and trim.

Most common questions I get from our guests are about the treatment of disposal of the waste water from the showers or accommodations area. While this will be another topic for another post, bilge water sadly is very little known to the public and yet, so important.

Hope you found this lesson of bilge treatment (in a nutshell) helpful and that it gives you better understanding on the efforts cruise ships take in protecting the seas. Let me know if you have any questions.


6 thoughts on “About bilge water treatment

  1. Sisonke says:

    wow this is so interesting, as I’m a young Girl whose about to embark in this industry. You such an inspiration keep shining and making us proud as Girls…


    • girlatsea1 says:

      Thank you Sarah! I actually shared your post as well on my Linkedin too. Very happy you enjoyed the article. Sorry for the late reply but I was away in vacation with limited internet access.

      Thanks and you also keep up the good work in keeping our Aegean sea clean! ๐Ÿ™‚



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