33
Anglo Eastern Maritime Training Centre A CASE STUDY ON OWS- ABUSE!!
Anglo Eastern Maritime Training Centre
A CASE STUDY ON OWS- ABUSE!!
Anglo Eastern Ship Management
2008
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.
NARRATIVE
Anglo Eastern Ship Management
2008
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.
INVESTIGATION FINDINGS / OBSERVATIONS
Anglo Eastern Ship Management
2008
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
2008
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
2008
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
2008
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
2008
HOLE ON THE WATER RISER PLATES AND GENERAL WASTAGE.
Anglo Eastern Ship Management
2008
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
DAMAGES TO OWS COMPONENTS
Anglo Eastern Ship Management
2008
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
2008
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
2008
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
2008
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
2008
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
2008
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
2008
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
2008
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.
REMEDIAL ACTIONS
Anglo Eastern Ship Management
2008
Introduction to Some concepts
Anglo Eastern Ship Management
2008
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
2008
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
2008
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
2008
A peep into the latest technology
MARIFLOC OWS and WHITEBOX
Anglo Eastern Ship Management
2008
Alfa Laval :- ECOSTREAM
Anglo Eastern Ship Management
2008
EcoStream – Typical system layout
Anglo Eastern Ship Management
2008
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
2008
OWS :- : Latest Technologies
Wartsila
With the acquisition of the Swedish company Senitec in 2007, Wärtsilä widened its scope of environmentaltechnologies to include products to handle waste oil and reduce the amounts of sludge and bilge to bedisposed of ashore.
Anglo Eastern Ship Management
2008
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
2008
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
2008
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
2008
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
2008
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
2008
Anglo Eastern Ship Management
2008
