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November 2010

Searchlight Feature - 6th November 2010

OWS - How Ineffective are they - A Taboo Subject - Why?

The effective operation of the OWS is such a delicate subject that many people avoid asking the people who have to try to operate them and avoid pollution - i.e. the ships staff – about their problems. Why do we hear so many cases of tampering with this equipment and fitting and using all sorts of avoidance techniques in the use of this equipment? Similarly C/E's are generally afraid to voice their opinions about them - why? There are several reasons:

  1. Pollution - deliberate or otherwise has been criminalised by certain bodies making it such that anyone voicing short comings with antipollution equipment is immediately suspected of being a polluter just because they are discussing problems with the operation of the equipment.
  2. If they put anything in writing on the subject they are severely castigated and accused of risking the Companies reputation.
  3. Companies do not want to hear anything, least of all in writing in case such emails are used in a court case at a future date if the Company experiences an oil spill.

So our efforts to clean up the oceans has led to a situation whereby we cannot freely speak or write about this equipment in a truthful manner for fear of being branded polluters and criminals - this is a fine situation to encourage progress and improvements! If you doubt this remarks then I can assure you that you have not investigated the matter.

In conjunction with the operation of the OWS the Oil Record Book (ORB) must be completed whenever oily bilges are pumped within the machinery space. If a superintendent or better still a ship manager were to spend 2 hours correlating the entries in the ORB with those in the E.R. fuel book and log book he is almost certain to find significant discrepancies. The author has checked this on many occasions.

Testing of New OWS's - How effective are the Rules?

As recently as a few months ago a major producer of OWS came out and implied that the static OWS do not meet the requirements of separating the oil from water “n themselves” because without “add on’s” like polishing filters the present static OWS cannot handle emulsified oil - which is the major form that the mixture takes. The MEPC resolutions for the testing of this equipment leaves loopholes that manufacturers exploit - even the new resolution MEPC 107(49) missed a major requirement for their testing - namely repeatability. If the equipment can sustain the test once for a specific period with emulsified oily water then it will be accepted. To achieve this a pre-polishing filter is fitted, it is irrelevant then that in real life it is important that the costs of filters are minimised - i.e. maximum filter life and the work should not be labour intensive. Some of these polishing filters are costing a vessel several thousand dollars per year for replacements alone.

Bilge Handling System

The workload of ships staff could be significantly reduced and the handling of oil water done far more reliably if a clean bilge tank was fitted as part of the bilge handling system. On many vessels over 80% of the ‘bilge water’ may be considered near pure water – this includes water from the main engine scavenge drain from before the scavenge air separators, drains from the fridge and A/C save-all’s, the HT and LT cooler save-all’s, FWG save-all’s and boiler drains! Such drains as these would be better being piped to a separate clean bilge holding tank from where they can be pumped directly over the ships side or treated differently from the bilges whose contents are, or could be, of suspect condition. An oil detector unit could be fitted in the clean bilge holding tank as an added precaution. Several Companies have been doing such for several years. It seems somewhat self-defeating to mix known clean bilges with bilge water of suspect condition and then put the complete contents through a very difficult process and thereby risk unnecessary oil contamination. This is just an idea but Class have been consulted on this subject and they agree this is feasible and would be approved on a ship by ship basis.

In addition we should consider sending OWS test drains to the oily bilge tank rather than to the present bilge holding tank since only a small amount of oil from operating such test cocks cause an out of proportion amount of contamination of the bilge tank. If we look at the handling of bilge water as a whole and not the OWS as a separate piece of equipment we could perhaps better solve the continuing problem of “oil and water” and make ships staff life on board a lot better - particularly that of the engine room staff.

Mixing approximately 80% of clean water with a remaining 20% of dirty water and putting the whole mixture through a difficult process makes no sense. Retain the clean water separately and handle a smaller amount of difficult liquid through a difficult process makes far more sense. In fact it makes one think - how could we be so stupid in the first place when the answer to the created problem is so simple. As indicated the suggested modifications will need to be discussed with Class for approval on behalf of Flag.

In our next Newsletter we will discuss the merits of a centrifugal OWS as opposed to the static type separators.

People within the Carmania organisation are fully qualified and willing to discuss and engineer improvements in your planned new builds and existing vessels should you be interested. It is a problem and has been there for a number of years and must be discussed if we truly are going to effectively have genuine near 'zero' oil pollution.