Transcript A case study on OWS- Abuse!!

A CASE STUDY ON
OWS- ABUSE!!
Anglo Eastern Maritime Training Centre
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.
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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.
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 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.
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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.
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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
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OWS CONDITION
 Serious damages
were observed on the
OWS components
 Many oil catch plates
were damaged due to
coating break down
and general wastage
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HOLE ON THE WATER RISER PLATES
AND GENERAL WASTAGE.
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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
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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.
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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?
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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.
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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.
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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
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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
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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
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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.
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Introduction to Some
concepts
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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.
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How do we measure turbidity?
Sampling tube
Measuring cell
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.
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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.
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We need to only
improvise on the
technique
A peep into the latest technology
MARIFLOC OWS
and WHITEBOX
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Alfa Laval :- ECOSTREAM
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EcoStream – Typical system layout
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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
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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.
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THE PRINCIPLES OF THE WÄRTSILÄ
SENITEC OILY WATER SEPARATOR
 The technology behind Wärtsilä Senitec M- and Pseries 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.
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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
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Stage 3 : Dissolved air flotation
and 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
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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.
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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
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Anglo Eastern Ship Management
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Anglo Eastern Ship Management
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