HELMEPA 2011 TRAINING PROGRAM
Exchange of Ballast Water at Sea and Onboard Treatment
1. The environmental problem
Globally, the number and frequency of invasions of alien species in marine
ecosystems are increasing. Invasive species are considered by scientists to be a major
threat to the marine environment, often with dramatic implications for biodiversity,
natural habitats and fishing.
Ships use ballast water to maintain their stability and structural integrity and ensure
the immersion of the propeller and rudder in the unloaded passage. It is closely linked
to the ship’s safe operation, since ballasting helps to restore balance during
loading/discharge operations and fuel consumption.
The environmental problem lies with the fact that ballast water is a vector of
thousands of species of animals and plants and also microorganisms (pathogens or
not), many of which succeed to survive temporarily in the ship’s tanks and are
therefore transferred to new aquatic ecosystems when ballast water is discharged.
Polluted marine areas are more susceptible to the establishment of harmful invasive
species, as ecosystem destabilization due to human activities such as over-fishing and
water pollution is a major factor in favor of a successful invasion of a species.
In the Black Sea for instance, over-fishing and eutrophication led to a massive
“blossoming” of the Mnemiopsis Leidyi population; a carnivorous jellyfish transferred
to the area in the beginning of the 80s through ballast water. This jellyfish consumed
large quantities of fish larvae and zooplankton, disrupting the whole food web and
leading to the collapse of fishing stocks.
With the constant growth of shipping, which serves 90% of the world trade, more than
10 billion tons of ballast water is discharged annually and invasive species are
increasingly transferred and successfully established in various marine areas, drawing
the attention of scientists and local authorities due to the serious ecological, economic
and social impact that these invasions often incur. Some of the transferred organisms
may present, under certain circumstances, a major threat to coastal ecosystems. There
have been many cases where the introduction and establishment of marine alien
species has had a detrimental impact. For example, the management of the European
mussel (Zebra Mussel), which was introduced to the Great Lakes in the mid-80s, costs
the U.S. many millions of dollars annually, not to mention the considerable ecological
damage inflicted upon the country’s inland waters.
The potential economic impacts are as follows:

Reduction of fish stocks and damage to fishing gear.

Negative impacts on tourism, as introduced species are often related to
eutrophication and water quality problems.

Substantial financial cost for the mitigation and management of their negative
impacts.
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HELMEPA 2011 TRAINING PROGRAM
The potential environmental problems are the following:
2.

Biodiversity loss and habitat degradation due to the competition between alien
and native species for food and space, the spread of new parasites and diseases
for which native species have not evolved adequate defense mechanisms, and
possible population blooms of invasive species, leading to oxygen depletion
and anoxic conditions.

Water quality degradation.

Changes to the food chain.

Disturbance of the whole ecosystem function.
The International Convention for the Management of Ballast Water
and Sediments
2.1 Introduction
Ballast Water Management means mechanical, physical, chemical and biological
processes, either singularly or in combination to remove, render harmless, or avoid the
uptake or discharge of harmful aquatic organisms and pathogens within ballast water
and sediments.
The International Convention for the Control and Management for Ships’ Ballast
Water and Sediments was adopted by IMO in 2004 with the aim to provide globally
applicable regulations to prevent, minimize and eliminate the risks to the
environment, human health, property and resources arising from the transfer of
harmful aquatic organisms. All vessels will be practically required to carry out ballast
water management to comply with specific standards depending on their ballast tanks
capacity and the year of built. These standards are the Ballast Water Exchange
Standard and the Ballast Water Performance Standard.
Although the Convention has not yet entered into force, several coastal states have
already established national standards on ballast water exchange procedures and have
specified the necessary documentation on the basis of IMO Resolution A.868(20).
Ballast water is essential to the safe and efficient operation of ships, controlling trim,
draft, stability, or stresses of the ship. However, ballast water may contain aquatic
organisms or pathogens which, if introduced into the sea including estuaries, or into
fresh water courses, may create hazards to the environment, human health, property or
resources, impair biological diversity or interfere with other legitimate uses of such
areas.
2.2 Duties of the Designated Ballast Water Management Officer
The Ballast Water Management Plan of the ship must designate the Officer onboard in
charge for ensuring that the plan is properly implemented. The Officer must:
-
ensure that the ballast water exchange follows the procedures in the Ballast Water
Management Plan, placing emphasis on the safety considerations,
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HELMEPA 2011 TRAINING PROGRAM
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obtain all available information in due time before arrival in the next port about
cargo prospects in respect of total quantities and discharging / loading sequence,
-
determine in accordance with the Master whether ballast water exchange is
required and create a step-by-step operational procedure,
-
supervise the operational procedures during ballast water exchange,
-
prepare action of the ballast water declaration form prior to arrival in port (this
includes to obtain information of the requirements of the Port Authorities of the
next visiting port),
-
maintain the ballast water handling log (incl. Ballast Water Record Book),
-
be available in port to assist the Port State control or quarantine officer for any
sampling that may needed to be undertaken,
-
organise the training for the crew in ballast water exchange procedures.
2.3
Ships’ Officers and Crew training
Ballast water exchange at sea is a comparatively new development; therefore it is to
be ensured that the officers and crew are familiar with the procedures for ballasting. A
regular training is to be performed in order to minimise possible safety hazards during
the exchange of ballast water as the operation can directly influence the vessel’s
safety. The following items should be familiar to all executing personnel:

the ship's pumping system in detail, including piping arrangement, involved
pumps and all arrangements of air and overflow pipes for co-ordination of the
crew working on deck,

functionality of the air pipe heads and the air/overflow pipes (blockage of
air/overflow pipes, ball failure, freezing or unintentional closure should be
kept under surveillance),

knowledge of expected time spans for ballast water exchange at sea. This
requires full knowledge over the ships' operational plan, the routing and the
time schedule for passages and ports. This could be relevant when the
exchange is prescribed in areas, such as open-ocean, deep water, high sea or
designated areas. In such cases it is necessary that the executing shipboard
personnel is familiarised with the respective definitions of these areas,

alternative methods of ballast water exchange. The involved risks and
consequences to ships' stability and strength and advantages of each method or
the possibility of using treatment alternatives,

procedures for recording (Ballast Water Record Book), sampling and sounding
to prove a proper record as postulated in the regulations,

ballast pump capacity restrictions, if any,

ballast water exchange procedures as stipulated by the shipyard or designer,
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HELMEPA 2011 TRAINING PROGRAM

precautions for entering tanks for sediment removal, further procedures for the
safe handling and packaging of sediment and storage thereof.
2.4 Procedures and operation of ballast water management systems
The designated Ballast Water Management Officer and the crew should be familiar
with the requirements of the Port Authorities with respect to ballast water and
sediment management, including information that will be needed to obtain entry
clearance. A ballast handling plan (Ballast Water Exchange Sequence) for a voyage
with ballast water is to be prepared in advance, whereby a step by step procedure for
the exchange of ballast water tanks is to be worked out. The Ballast Water Exchange
Sequence should be based on the specific loading condition for which it is intended
for.
In general exchange of ballast water should be carried out in a deep sea condition. It is
recommended to perform ballast water exchange at least 200 nm from the nearest land
and in waters at least 200 m in depth, if this is not possible at least 50 nm from the
nearest land and in waters at least 200 m in depth or in areas designated by the Port
State.
If ballast water exchange is not undertaken for any reasons e.g. if the Master
reasonably decides that such exchange would threaten the safety or stability of the
ship, its crew, or its passengers because of adverse weather, ship design or stress,
equipment failure, or any other extraordinary condition, then details of the reasons
ballast water exchange was not undertaken are to be recorded in the Ballast Water
Record Book. Such a statement will assist the Master when responding to enquiries
from a quarantine officer.
The necessity of ballast water exchange depends on several environmental conditions
such as location of ballast water intake/outtake, biological conditions etc. However,
the definite need to perform ballast water exchange depends on national regulations of
the responsible Port Authority in the arriving port; it is therefore recommended
contacting them in due time.
Commonly only tanks which shall be discharged in the next port are subject to Ballast
Water Management, i.e. only these tanks need to be exchanged with new water in a
deep sea condition.
2.5
Precautionary practices
Care should be taken to avoid unnecessary discharge of ballast water that has been
taken up in another port. It is noted that managed ballast water which is mixed with
unmanaged ballast water is no longer in compliance with respective requirements.
When loading ballast water, efforts should be made to avoid the uptake of potentially
harmful aquatic organisms, pathogens, and sediment that may contain such organisms.
The uptake of ballast water should be minimized or, where practicable, avoided in
areas and situations such as:
-
in areas identified by the Port State in connection with advice provided by ports
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in darkness when organisms may rise up in the water column
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HELMEPA 2011 TRAINING PROGRAM
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in very shallow water
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where propellers may stir up sediment
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where dredging is or recently has been carried out.
2.6.
Methods of ballast water exchange
2.6.1.
Sequential method
A process by which a ballast tank is first emptied and then refilled with replacement
ballast water to achieve at least a 95% volumetric exchange. For this method each
ballast tank should be discharged until suction is lost and stripping pumps or eductors
should be used if possible. Thus the process requires the removal of very large
weights from the ship in a dynamic situation, and then their replacement.
By using this method the original loading condition is changed which has a major
influence on the stability behaviour, structural strength, visibility and
manoeuvrability. In this regard all Safety Considerations and Limitations are to be
observed.
A step by step procedure has to be applied, listing the order of processed tanks. For
each exchange step the intermediate loading condition during sequential exchange is
to be pre-calculated.
Special attention should be paid to considerable heeling moments resulting from
exchange of tanks with different volumes or one-sided sequential ballast water
exchange. This heel can be reduced by simultaneous measures like ballast water
exchange of an opposite tank or by counter-filling of another empty tank. In general a
heeling angle of 2.0 deg. shall not be exceeded. Thus, the availability of a pair of
empty spare tanks could be helpful to successfully conduct ballast water exchange.
This circumstance should be taken into account during the planning of the ballast
water distribution.
2.6.2 Flow-through method
This is a process by which ballast water is pumped into a ballast tank, allowing water
to flow through, overflow or other arrangements.
It is recommended by IMO Res. A.868(20) and established by most Port State
Authorities that at least three times of the tank volume should be pumped through the
tank. With it, normally an exchange of 95% of the ballast water may be achieved.
When the flow-through method is applied suitable overflow points for each tank need
to be arranged on the vessel (e.g. bypass at the airpipe, overflow hatch, overflow
piping system, etc.). For this method additional pressure on the steel structure of the
tank boundaries can occur (pressure loss calculation). Prior to application it is to be
proved that the steel structure is sufficient to compensate that additional tank
pressure!
A step by step procedure has to be applied, listing the order of processed tanks. For
each step the tank, its volume, used pumps and the time for three exchanges is stated.
A direct overflow via the airpipe head is not permitted as the long term load would
lead to a failure of this component (respectively of the tank boundaries) and thus
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HELMEPA 2011 TRAINING PROGRAM
jeopardize the watertight integrity of the vessel. In any case, after each ballast water
exchange, a thorough check of each airpipe head for the functionality should be
carried out.
2.6.3 Dilution method
The dilution method is a process by which replacement ballast water is filled through
the top or side of the ballast tank with simultaneous discharge from the bottom or
opposite side at the same flow rate and maintaining constant level in the tanks through
out the ballast exchange operation. At least three times the tank volume is to be
pumped through the tank. For the dilution method a suitable piping systems (ring
system) needs to be installed with separate inlets and outlets for each tank.
Commonly two ballast pumps are used simultaneously, whereby one is acting as
filling pump and the other as suction pump. As it is essential to keep the filling level
in the tanks constant, an exact control of the pumped volume of both pumps is to be
ensured.
2.6.4 Sediment management
All practical steps should be taken during ballast uptake to avoid sediment
accumulation, however, it is recognized that sediment will be taken on board and will
settle on tank surfaces.
The volume of sediment in a ballast tank should be monitored on a regular basis.
Sediment in ballast tanks should be removed in a timely basis and as found necessary.
The frequency and timing of removal will depend on factors such as sediment build
up, ship’s trading pattern, availability of reception facilities, work load of the ship’s
personnel and safety considerations.
Removal of sediment from ballast tanks should preferably be undertaken under
controlled conditions in port, at a repair facility or in dry dock. The removed sediment
should preferably be disposed of in a sediment reception facility if available,
reasonable and practicable. When a tank is entered for sediment removal appropriate
safety considerations are to be observed.
When sediment has accumulated, consideration should be given to flushing tank
bottoms and other surfaces when in suitable areas, i.e. out side 200 nm from the
nearest land and in waters at least 200 m in depth, if this is not possible at least 50 nm
from the nearest land and in waters at least 200 m in depth.
2.6.5 Recording and reporting requirements
To facilitate the administration of ballast water exchange (and treatment procedures, if
applicable), the designated Ballast Water Management Officer is responsible for a
continuous and correct record keeping.
When carrying out ballast water operations the details are to be recorded in the Ballast
Water Record Book together with any exemptions, if applicable. The form and the
entries in the Ballast Water Record Book follow:
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HELMEPA 2011 TRAINING PROGRAM
BALLAST WATER RECORD BOOK
Entries in the Ballast Water record book shall be made on each of the following
occasions:
1 When Ballast Water is taken on board:
1.
Date, time and location port or facility of uptake (port or lat/long),
depth if outside port
2.
Estimated volume of uptake in cubic metres
3.
Signature of the officer in charge of the operation.
2 Whenever Ballast Water is circulated or treated for Ballast Water Management
purposes:
1.
Date and time of operation
2.
Estimated volume circulated or treated (in cubic metres)
3.
Whether conducted in accordance with the Ballast Water Management
plan
4.
Signature of the officer in charge of the operation
3 When Ballast Water is discharged into the sea:
1.
Date, time and location port or facility of discharge (port or lat/long)
2.
Estimated volume discharged in cubic metres plus remaining volume in
cubic metres
3.
Whether approved Ballast Water Management plan had been
implemented prior to discharge
4.
Signature of the officer in charge of the operation.
4 When Ballast Water is discharged to a reception facility:
1.
Date, time, and location of uptake
2.
Date, time, and location of discharge
3.
Port or facility
4.
Estimated volume discharged or taken up, in cubic metres
5.
Whether approved Ballast Water Management plan had been
implemented prior to discharge
6.
Signature of officer in charge of the operation
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HELMEPA 2011 TRAINING PROGRAM
5 Accidental or other exceptional uptake or discharges of Ballast Water:
1.
Date and time of occurrence
2.
Port or position of the ship at time of occurrence
3.
Estimated volume of Ballast Water discharged
4.
Circumstances of uptake, discharge, escape or loss, the reason
therefore and general remarks.
5.
Whether approved Ballast Water Management plan had been
implemented prior to discharge
6.
Signature of officer in charge of the operation
6 Additional operational procedure and general remarks
The volume of Ballast Water onboard should be estimated in cubic metres. The
Ballast Water record book contains many references to estimated volume of Ballast
Water. It is recognized that the accuracy of estimating volumes of ballast is left to
interpretation.
Where a Port State requires information on ship’s ballast operations, relevant
documentation should be made available to the Port State. The respective Ballast
Water Reporting Format included in the Resolution A.868 (20) is shown in the end of
this section.
2.6.6 Sampling points
Sampling of ballast water is primarily a matter for the authorized inspection officers
during Port State Control. For crew members it is unlikely to take samples from the
ballast water except at the expressed request, and under the supervision, of the
authorized inspection officers. However, in case a quarantine officer requires such
tests the exact position of each sampling point is to be known. In general all sounding
pipes can be used as sampling points (see table), additionally manholes can give
access to the ballast water tanks. - Port State Control Officers should be advised of all
safety procedures to be observed when entering enclosed spaces.
2.6.7 Safety considerations
Unless applied carefully some of the measures being urged for Ballast Water
Management can affect the ship’s safety, either by creating forces within the hull that
could exceed design parameters (longitudinal strength, bottom slamming, sloshing,
overpressure), or by compromising the stability of the vessel (free surface effects, loss
of mass). This possible conflict with safety is to be considered during the decision
making process to carry out ballast water exchange.
The exchange of ballast water should only be conducted under consideration of all
safety margins. Conditions which would make a ballast water exchange at sea unsafe
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HELMEPA 2011 TRAINING PROGRAM
should be identified. In terms of safe passage ballast water exchange should not be
undertaken in situations such as:
when weather conditions do not allow a safe procedure. Considerations about the
weather situation shall include wind and sea state furthermore speed and direction
as well as icing conditions
during periods of equipment failure or defects
any other circumstances in which human life or safety of the ships is threatened.
-
-
The decision whether ballast water exchange should be conducted or not rests in the
responsibility of the ship’s master. After each step, decision of proceeding to next step
should be made by taking into account the ship’s position, weather forecast,
machinery performance and degree of crew fatigue. If any of the factors are
considered unfavourable the ballast exchange should be suspended or halted.
In order to make the correct decision which exchange method is to be chosen all
intermediate steps of exchange should be pre-calculated and monitored with the
Loading Computer on board of the vessel.
2.7
Ballast water treatment onboard
2.7.1 General
Regulation D-2 of the Convention includes the ballast water treatment or performance
standard, commonly referred to as the D2 Standard.
This standard essentially determines the required quality of ballast water discharged
into the sea after its treatment on board. The critical parameter taken into account is
the concentration of viable organisms in the discharged ballast water, according to
specific size classes. Viable organisms are considered those which after ballast water
treatment are still able to complete their life cycle and reproduce.
Even though the Convention aims to control harmful aquatic organisms and pathogens
in ballast tanks, the treatment standard takes into account all organisms encountered in
ballast water. Viable organisms of size equal or greater than 50 μm (1 μm = 1/1000 of
millimetre), mainly zooplankton, shall be less than 10 per cubic metre in the treated
ballast water to be discharged.
The next size class of aquatic organisms defined in the standard is between 10 μm and
50 μm, mainly phytoplankton. Ballast water treatment shall ensure that discharged
ballast water does not contain more than 10 viable organisms per millilitre (ml).
Standard D2 also includes microbial contamination indexes aiming to minimize the
risk of transfer of pathogens when ballast water has been pumped into the ship from
ports with polluted waters.
Type of organisms
Required concentration
Viable organisms with size 50 μm or
greater
< 10 per 1 m3 of ballast water
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HELMEPA 2011 TRAINING PROGRAM
Viable organisms with size
10 - 50 μm
< 10 per 1 ml of ballast water
Vibrio cholerae bacteria
< 1 colony forming unit per 100 ml
E. coli
< 250 colony forming units per 100 ml
Enterococci
< 100 colony forming units per 100 ml
2.7.2 Installation of ballast water treatment systems on board ships
Depending on the year of construction and the capacity of the ballast tanks, ships shall
install a permanent ballast water treatment system according to the following
timetable, as set by the Convention. An approved ballast water treatment system must
be progressively installed on all ships no later than 1st January 2016, under the
condition that the Convention will have entered into force prior to this date. Ships
which are the first among those required to install an approved ballast water treatment
system are those constructed after 1st January 2009, that have a total ballast water tank
capacity of less than 5,000m3.
2.7.3 Approval requirements for ballast water treatment systems
One of the innovations of the Convention is the approval procedure of ballast water
treatment systems that make use of active substances, i.e. chemical substances which
are added or generated during the treatment process. This procedure consists of the
stage of Basic Approval for the active substances used and the stage of Final
Approval for the treatment system. Both approvals are exclusively granted by the
IMO Marine Environment Protection Committee, while the Type Approval is issued
by the Flag Administration or recognized Classes. The above procedure aims at
ensuring that treated ballast is not harmful to the environment when discharged into
the sea. This is particularly important, given that ships with high tank capacity and
ballast uptake rates obviously discharge large volumes of ballast water. In the case
that considerable quantities of chemical substances are stored on board for the needs
of the treatment system or produced during the ballast treatment process, the safety of
the crew must also be ensured.
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