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NARRATIVE The vessel was in the dry dock in the first week of Feb 2001 in Vietnam.The overboard valve and the oily water separator discharge pipe was opened up for inspection in the dry dock.It was reported that there was oil found in the overboard pipe line and subsequently the Technical Office requested for an investigation. Anglo Eastern Ship Management
INVESTIGATION FINDINGS / OBSERVATIONS • The oily water separator was not functioning properly due to the damaged internal parts of the separator and faulty first stage oil sensor. • The malfunctioning of the oily water separator has resulted in carrying over the oil to the second stage and subsequently to overboard. • The bilge pumping operation was carried out by the motormen with little supervision by the engineers. Anglo Eastern Ship Management
The motorman was made to stand by next to the OWS to monitor the oil from the sampling cock and to operate the first stage oil drain valve manually (as the auto drain valve was not working due to faulty oil level sensor) to empty the oil into the sludge tank. • The Human error by the crew can not be ruled out as he may have been involved in other engine room jobs as well. Anglo Eastern Ship Management
MANAGEMENT OF LARGE QUANTITY OF BILGE WATER • Vessel used to leave a port after two day’s port stay with a large quantity of bilge water as the leakages are bit more, especially from the ballast pumps, whose mechanical seals were leaking. • When they pump out the muddy water, the 15 ppm sensor was put off and the 3 way valve was made to remain open to overboard. • The motorman was continuously monitoring the water sample to check for the presence of oil and stop the pumping immediately, if required. Anglo Eastern Ship Management
POOR BILGE MANAGEMENT • The clean bilge tank was not maintained clean at all, but mixed with oil residues, which made the bilge management even more difficult. • The bilge pump also was observed to be not working efficiently due to worn out internal parts Anglo Eastern Ship Management
OWS CONDITION • Serious damages were observed on the OWS components • Many oil catch plates were damaged due to coating break down and general wastage Anglo Eastern Ship Management
HOLE ON THE WATER RISER PLATES AND GENERAL WASTAGE. Anglo Eastern Ship Management
DAMAGES TO OWS COMPONENTS • Wastage on three places on the oil ascending pipe chamber (repaired as shown in the photograph). This caused the mixing of water with separated oil. • Coalescer filtering inserts were missing in the second stage Anglo Eastern Ship Management
Living Dangerously • The condition of this IOPP equipment clearly indicated that it was not in good operating condition as required under MARPOL which itself is a detainable deficiency. • The ship staff /ship/ company/owner are answerable • It attracts criminal prosecution in some countries for not declaring the “Truth/Fact” and due to falsification of records. Anglo Eastern Ship Management
TASK • Please analyze the case: A) What are the reason for a bad practice being followed onboard ship? B) As a C/E: how would you stop such bad practices onboard. C) List out what are the pro active action which was lacking from the Office side? Anglo Eastern Ship Management
WHAT WENT WRONG • The bilge separator was not functioning the way it supposed to be working, due to the following :- aa) The internal components were not operational due to poor condition of plates, wastage on first stage oil division plate and absence of second stage coalescent filter elements. This has resulted in carrying over of oily mixture to the second stage and poor separation at the second stage. Anglo Eastern Ship Management
WHAT WENT WRONG bb) Absence of internal inspection and maintenance deteriorated the performance of the oily water separator. • The basic problem with the oily water separator was not identified in time and system was working with short term strategies. • In fact the separator was working in very poor condition, which was not identified until the internal inspection carried out. Anglo Eastern Ship Management
WHAT WENT WRONG • This valve was operated manually by the motorman, whenever he observes oil from the sampling cock. This short term strategy of operating the oil discharge valve became a long term strategy and eventually into a substandard practice and being continued onboard for quite some time. The custom made tool appeared to have been in use for a long time Anglo Eastern Ship Management
WHAT WENT WRONG • The drawing for the internal arrangement of the oily water separator available onboard was for a wrong type of equipment (Type B) while the correct equipment fitted onboard was of Type A. • This was pointed out by the makers on 15th Sept 05, when the spare parts were ordered for the oily water separator Anglo Eastern Ship Management
REMEDIAL ACTIONS • Follow the company instructions as per MTM 7.9 maintain and record keeping of oily water separator, including testing of 15 ppm monitor with calibration liquid. • Short term strategies adopted should be discontinued, once the problem is fixed and should not be allowed to become a practice onboard. • Strict compliance of company policy and procedures on environment protection should be observed by all onboard Anglo Eastern Ship Management
REMEDIAL ACTIONS • Minimise engine room leakages into the bilges, by keeping the sea water / ballast pumps in good condition. • Keep bilge tank (clean) always free from oil and use it exclusively to transfer clean bilge water. • Monitor the performance of the equipment time to time and replace the / repair the parts as soon as possible, OWS being a critical equipment. • The requisitions for the oily water separator and bilge pump should be handled urgently, if situation demands. • Carry out the function test of first stage oil sensor more frequently to ensure the proper operation. Anglo Eastern Ship Management
Introduction to Some concepts Anglo Eastern Ship Management
What is the Oil Content Meter measuring? 15ppm?? • It measures the turbudity of the liquid • Turbidity is a measure of the degree to which the water looses its transparency due to the presence of suspended particulates and oil. • The more total suspended solids in the water, the murkier it seems and the higher the turbidity. • Turbidity is considered as a good measure of the quality of water. Anglo Eastern Ship Management
How do we measure turbidity? Turbidity is measured in NTU: Nephelometric Turbidity Units. The instrument used for measuring it is called nephelometer or turbidimeter, which measures the intensity of light scattered at 90 degrees as a beam of light passes through a water sample. Sampling tube Measuring cell Anglo Eastern Ship Management
How to estimate the condition of water in the Bilge holding tank Principle:- In lakes the turbidity is measured with a secchi disk (in the picture). This is a black and white disk that is dropped in the water attached to a rope. The depth that the disk reaches before it disappears from sight is recorded. This provides an estimation of the turbidity level in the tank. We need to only improvise on the technique Anglo Eastern Ship Management
A peep into the latest technology MARIFLOC OWS and WHITEBOX Anglo Eastern Ship Management
Alfa Laval :- ECOSTREAM Anglo Eastern Ship Management
EcoStream – Typical system layout Anglo Eastern Ship Management
OCM • Continuously monitors and displays ppm value of cleaned water • Automatically recirculates cleaned water exceeding 15 ppm back to bilge tank • Stores values for 18 months Anglo Eastern Ship Management
OWS :- : Latest Technologies Wartsila With the acquisition of the Swedish company Senitec in 2007, Wärtsilä widened its scope of environmental technologies to include products to handle waste oil and reduce the amounts of sludge and bilge to be disposed of ashore. Anglo Eastern Ship Management
THE PRINCIPLES OF THE WÄRTSILÄ SENITEC OILY WATER SEPARATOR • The technology behind Wärtsilä Senitec M- and P-series is a combination of optimized traditional methods, and innovative new solutions. It consists of a four-stage, emulsion-breaking separator, where each stage handles one key component of the sludge and bilge mix. It can handle input flows with an oil content of between 0 and 100%, making it the most versatile separator on the market. • Stage 1 : Dissolved air flotation and oil skimming by a combination of dissolved air and a unique dual oil zone interface stage, the oil floats to the surface, where it is skimmed off and pumped to the waste oil (sludge) tank. Anglo Eastern Ship Management
Stage 2 : Emulsion breaking • The processes of coagulation and flocculation are employed to separate the suspended solids from, and break the emulsions in, the bilge water. • Dispersed solids (colloids) suspended in the bilge water are stabilized by negative electric charges on their surfaces, causing them to repel each other. Since this prevents these charged particles from colliding to form larger masses, called flocs, they do not settle. To assist in the removal of colloidal particles from suspension, chemical coagulation and flocculation are required. These processes, usually done in sequence, are a combination of physical and chemical procedures. Chemicals are mixed with the bilge water to promote the aggregation of the suspended solids into larger particles. To achieve maximum effect, the mixing of the different chemicals must be performed with the utmost control. Once the suspended particles are flocculated into larger particles, they can be removed from the liquid by flotation Anglo Eastern Ship Management
Stage 3 : Dissolved air flotationand sludge skimming Dissolved air flotation is used again to promote the separation and subsequent removal of the solids to the solids tank. The open design of the system makes it easy to have full control and to maintain and run the unit with a minimum of effort Anglo Eastern Ship Management
Understanding Coagulation Coagulation is the destabilization of colloids by neutralizing the forces that keep them apart. Cationic coagulants provide positive electric charges to reduce the negative charge (zeta potential) of the colloids. As a result, the articles collide to form larger particles (flocs). Rapid mixing is required to disperse the coagulant throughout the liquid. Anglo Eastern Ship Management
Understanding Flocculation • Flocculation is the action of polymers to form bridges between the flocs, binding the particles into large agglomerates or clumps. Bridging occurs when segments of the polymer chain adsorb on different particles and help particles aggregate. An anionic flocculant will react against a positively charged suspension, adsorbing on the particles and causing destabilization either by bridging or charge neutralization. • In this process it is essential that the flocculating agent be added by slow and gentle mixing to allow for contact between the small flocs, and to agglomerate them into larger particles. Anglo Eastern Ship Management
