The purification equipment for separating oil and other pollutants from engine room bilge water has been updated several times over the years. From the 1970s with Regulation 393X through to MEPC 60 (33) in the 1990s and on, until the regulation we have today; MEPC 107 (49) which came into force in 2005.
The regulations that have been in force to date have tested the equipment’s ability to separate HFO and diesel fuel from water. In the regulation that now applies, a chemical has also been added to the water in a final step for 150 minutes as an emulsion maker along with equal parts (2.5%) of HFO and diesel oil.
Even in 2005 at the time the present MEPC 107 (49) regulation was passed, it did not reflect reality since it did not test for lubricating oils or hydraulic oils that are also in the engine room. Furthermore, it was decided to test with a chemical and to allow for testing to be done land-based without the requirement for tests to be done on board.
The reality today regarding chemicals and fuels differs dramatically from what it looked like 15 years ago. Today we have fuels such as LNG or methanol. In these cases, there is nothing but lubricating oil or other special oils that need to be separated from water!
From 2020 onwards, to meet new requirements of maximum 0.5% sulphur content, we must also consider this new type of fuel that is often a mixture. Such blended fuels had not existed before and it is not known ‘if and how’ existing separators will be able to properly separate them. Additionally, the use of chemicals is completely different today; apart from chemicals used for different treatments and cleaning, there may also be residues from ballast water treatment systems or from scrubbers.
All in all, it is impossible to expect a bilge water separator approved according to MEPC 107 (49) in 2005 or older, to work with the same efficiency today. Resultantly, one would expect that much of the water from the engine rooms is not being purified to the extent required by existing regulations; this is indeed observed in all the cases in the past 15 years that the USCG imposed fines for!
It is not reasonable that we have a test procedure for these types of separators, that gives certification in theory that they function properly but in practise leaves crew with no ability to meet the legal requirements imposed on them. Inevitably, crew and shipowners remain at risk of extortionate fines and even possible prison sentences.
The question that needs to be asked is; How could a new test be designed to ensure that certified separators on the market can in fact meet the requirements set by IMO for cleaning bilge water to a maximum of 15 ppm oil content before it is released overboard?
Of course, a land-based test should be an option as a first check on any separator’s efficiency. Thereafter, the route to certification should be supplemented with a recorded test over time on at least 3 vessels, preferably on ships using different fuel types, before a separator can be finally certified.
Innovation regarding new fuels and regulations is very welcome. Innovation in the equipment tasked with processing these new fuels, while adhering to new regulations, must follow the same evolutionary path.
The end goal after all is to achieve a clean environment, and that each industry ensures in practise, as well as in theory, that they avoid further polluting our already polluted world.
With a background as a marine engineer and as one of the founders of Marinfloc AB, Benny Carlson has been one of the leading authorities in waste water treatment on board ships for the last 30 years.