Surveyors and port state inspectors are forever highlighting the fact that they have "found yet another vessel with a supposed magic pipe fitted", another with "no functioning Oily Water Separator (OWS on-board" and yet another with no magic pipe but just the main bilge pump on direct discharge overboard. Engineers today are still bucking the law, bypassing and inventing forever fanciful methods to dispose of bilge matter to the sea but why are they doing this? By breaking this law they are placing themselves in-line for a heavy fine, a possible prison sentence and without doubt the loss of their job! Why would any engineer go to these lengths?

Oily water separators (OWS) are installed on most merchant vessels over 500 grt. There function is to separate oil from water to 15 parts per million or less. The separated oil to be retained on-board and disposed of ashore when possible and the water pumped overboard as it is extracted. The water and oil mixture is collected from various points around the vessel; oil from leaking oil lines, oil changes on machinery and purifiers and tank drains! The water comes from washing down, leaking salt water lines, cooler cleaning, etc and most of the water and oil ends up in the engine room bilges (the open space underneath the machinery). This is then typically pumped to the bilge holding tank, or sucked direct through the OWS.

I have been at sea for twenty years and in that time have come across maybe one, possibly two Separators that actually work as they were designed to! For the most part they require constant attention, seriously under-perform and consist of endless retrofits that engineers and companies have made to try and improve there performance or bring them up to standard, re: new legal requirements or requirement for increased throughput! In my time at sea I have never been able to switch on an OWS and walk away, confident that it will perform correctly and do the task that it was designed to do! This in itself is a problem as an engineer is taken away from other tasks and maintenance goes downhill, especially on vessels that sail under minimum manning, have undersized units and excessive water/oil in their bilges.

On a par with other machinery found on vessels they are high-maintenance! Purifiers or clarifiers do a similar job, they separate two differing mixtures from each other (water and solids from oil) and for the most part once started they are left to their own devices! Separators though require constant adjustments, cleaning, filter changes, removal of air, clean water sampling adjustment, back pressure change, suction filters cleaned, lenses cleaned, oil tank emptied, control air adjusted, burst hoses, blocked hoses, solenoid valve failure, splattering of oil from test pipes all over the engine room and the engineer, lost suction, and so on and on and on. The list is endless and painful and leads to one end result, that of frustration and anger at the machine itself, the company and the law that binds!

Companies the world over have failed to appreciate and/or act upon the new regulations fully, often because of the additional cost involved but also because they feel that bilge matter and its disposal is a matter for the ship and its crew rather than the office staff. For the most part superintendents ashore have coped with the increase from 100ppm to 15ppm overboard limits by retrofitting a 15ppm meter on an existing unit. All that this has done in practical terms is to increase dramatically the work that engineers have to do to get the machine to work to this end! Many of these machines were not designed for 15ppm separation, the mere fitting of a device that checks the overboard discharge does not suddenly make the separator perform to a better degree than before it just makes it harder to achieve the end result!

I once had a long conversation with an ABS surveyor about oily water separators! He was of the same opinion as I, that the system and the whole arena surrounding oil and its separation had gone way out of control! He even dared to mention that 15ppm was an unrealistic figure, that laws and paperwork had overtaken common sense but ……….. it was certainly nice to know that I was not alone in the world. We also covered such topics as bilge holding tanks, tanks that are far too small for today's heightened regulations and how companies are unwilling to accede to larger holding tanks and more of them as it encroaches on cargo carrying/ballast/fuel capacity, and we arrived at a similar conclusion; that engineers are being forced into a corner!

Engineers are frustrated. They are being asked to spend hours every day with a machine that they know is inadequate for the job! They also know that complaining about it will achieve nothing apart from rubbing up the office staff the wrong way! On a ship were the engineers have spent days sifting the oil from water they now come to the equally 'gritty' task of asking the company for a sludge truck so that the cycle can be completed! This forever seems to be an issue with the office and increases the pain of the engineers involved! Companies typically ask "were did all the sludge/waste materialize from" and then progress to complaining volubly with frequent references to the cost of the waste removal!

Is it any wonder that some engineers might turn to "magic pipes" as the press like to call them? An engineer who feels insecure over his job, who might be new to the company or who is afraid of his superior (the third to the second, the second to the chief) would be unwilling to ask the company for a sludge truck and so a rules are broken for self-survival!

When surveyors inspect a vessel and find faults with the system it is the engineers on-board that are penalized or reprimanded! The company denies any knowledge of anything illegal being done and they typically set-up an investigation into 'who did it' and 'why'! The engineer meanwhile skulks off back home …………. the company have their scapegoat.

I am positive that if more effort was placed on research and development an OWS could be produced that is self-sufficient, that does not require endless pernickety maintenance and that just ticks away on its own doing the job that it was designed to. If such a separator was produced, if shipping managers and technical superintendents swallowed the costs of sludge disposal without murmur and if older OWS units were replaced in their entirety with new and larger models instead of inane retrofits then engineers on-board would not resort to tricks and illegal means to dispose of their bilge matter!

Ieuan Dolby
Author and Webmaster of Seamania

Hello Ieuan,

Hope you are well, I was surfing the internet on oily water separators and I came across your article regarding 'Oily water separators and those Magic Pipes'.

I read it with interest and I agree with you on all your points made. You have condense the views of the many crew members and the surveyors we speak to but I thought that you would like an insight of what a manufacturer of OWS thinks.

I have been designing bilge separators for three years now and as private company we are driven by profit and sales. When I first took the job I developed a product that was designed to treat 'bilge' water to under 15ppm. We did this with great success (we have been making these since 1925 and realise the problems with the older versions) and were extremely confident that this new system would 'change' the perception of OWS, to people like yourselves, who have had to work with 'inadequate' equipment for the job. However after much promotion (to many customers including the MOD) we didn't manage to sell one unit although feedback was brilliant and they could see it working well - the reason, cost and also the no-confidence that separators never work and never will mentality.

The company got me to look at the IMO regulations again and reassess the situation - to pass this new IMO test was still simple. Whoever wrote them does not realise what goes into bilges and the main causes why OWS do not work in the field.

OWS are designed as oily-water separators (as the name suggests) and not really designed as sludge, laundry water, rust, solids, bacteria, discolouration, antifreeze, coolant and chemical separators which can occur in bilge water which can cause it to malfunction. The IMO test only requires neat fuel oils as a test liquid. For us to design a unit that can ultimately treat all contaminates is possible but will involve a lot more processes. However in the marketplace there are only separators that comply with the test liquids which require minimum technology/size. A more capable unit would cost 5 times the unit that is designed to specifically to comply with the test. Shipyards and ship-owners only look at initial costs when constructing a ship and they will go with the one that is least expensive with the correct certificates. The technology is there to treat bilge, 15ppm is achievable easily, I can draw up a design within a minute - the problem is convincing the shipbuilders and owners to buy a more expensive product and stop buying the 'inferior' products for their crew to use.

Another misunderstanding is that when the alarm goes off on the oil content monitor they immediately assume the separator is not working? The engineers on board will always believe the alarm - 9 out of 10 cases (our knowledge), it is the alarm misreading, you may know that most oil content monitor use a light scattering device to detect oil, not a good method! Basically it is a turbidity meter, measures light scatter (due to cost) and if the water is discoloured, has saturated air, solids, anything other than pristine water (15ppm is very clear water!), then the alarm will go. Try pouring milk in and the OCD will alarm off the scale, put pure ethanol in it and it will read zero, but is this monitoring oil? An accurate pure 'oil' content monitoring device will cost 10x-25x of the present monitors, you probably need an analytical chemist to analysis the data too as fuel oil is vastly complex. The separator can only be as good as its monitor.

As what we deem as 'quality' manufacturers we are as frustrated as the engineers are. We want to offer products that are hassle-free and reliable but then we will not commercially be able to survive cause there will always be someone selling cheaper units as the owners are only buying those. I felt that the manufacturers also get a hammering at times for mis-performing OWS's but I believe manufacturers are pushed into making units that are sometimes inadequate.

It is important for us to speak to engineers like yourself for us to appreciate your concerns so we can do something about it.

I hope you find this of interest,

Kindest Regards

Antony Chan
Victor Marine Limited