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FOREWORD
The Ports Corporation of Queensland has provided funding, operational
support and an industry focus for this research into the very important
question of how to minimise the spread of exotic organisms via ships'
ballast water. The Corporation believes that it is necessary for ballast
water treatment to be rigorously evaluated using the best techniques available,
both to determine the treatments that are likely to be successful as well
as those that are not. This work by Mr. Oemcke and Prof van Leeuwen at
the Cooperative Research Centre for the Ecologically Sustainable Development
of the Great Barrier Reef, based in Townsville, Queensland, is among the
first research of its kind and has led to a synthesis of important data
and the development of new ideas. It provides the shipping and ports industries
with high quality, relevant data, which can be used as a basis for proceeding
towards the treatment of ballast water in an environmentally responsible
and economical manner. Particularly, this report provides insights into
the design requirements for ballast water treatment plants and the practical
difficulties associated with the exchange of ballast water at sea.
The Ports Corporation of Queensland is operationally focused and does
not usually provide financial support for fundamental research but, in
this case, takes the view that this strategic research is of substantial
long-term benefit and should lead to the further practical development
of ballast water treatment systems by other organisations. The Corporation
encourages national and international maritime industries to take this
work into consideration as they further address ways of reducing the adverse
impacts that have occurred, and are still occurring, as a result of ballast
water being discharged into ports throughout the world. The Corporation
commends the CRC Reef Research Centre Ltd for also supporting this research.
Derek Andrews
Chief Executive Officer
Ports Corporation of Queensland
EXECUTIVE SUMMARY
The Ballast Water Treatment project at the CRC Reef Research Centre
Ltd, funded by the Ports Corporation of Queensland, aims to test technologies
or techniques which can be used to remove exotic organisms from ships'
ballast water. Techniques currently being examined for their potential
to disinfect ballast water are ozonation, ultraviolet irradiation (UV)
and filtration. To develop treatment systems for ballast water, it is
necessary to understand some of the chemical and physical characteristics
of the water to be treated.
The aims of the ballast water sampling program were to:
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Determine the sizes of solids and organisms present in ballast water
and analyse the effectiveness of filtration both as a pretreatment
to disinfection and as a disinfectant.
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Determine if ballast water, as landed after a voyage, had any characteristics
which would impact adversely on filtration, UV irradiation or ozonation.
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Investigate the potential for chemical and physical characterisation
of ballast water as a tool to verify that ballast water exchange had
been conducted effectively.
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To develop sampling methods for determining the chemical and physical
characteristics of ballast water.
Ballast water samples were taken from a number of vessels entering North
Queensland ports during 1995 and 1996. Water, sludge and sediment samples
were analysed for a range of physical and chemical characteristics which
will affect filtration, UV irradiation and ozonation, and which may be
useful for determining if ballast exchange at sea had been conducted.
Filtration may be necessary to reduce suspended solids prior to ozonation
or UV irradiation. Only pilot testing can determine if it is necessary
or effective. Without flocculation, screens of 20 to 30 µm would
probably be necessary. Filters can also be used as a disinfection treatment
for some organisms. 50 µm screens could be used as a stand alone
treatment to remove zooplankton from ballast water and 20 µm screens
should remove dinoflagellate hypnocysts, which are an important species
of concern in ballast water. Viruses, bacteria, and many amoebae, protozoans,
diatoms and dinoflagellate algae will not be effected by 20 µm screening.
UV irradiation may be limited to shipboard treatment, as the iron levels
in ballast discharges may cause iron precipitation on UV lamps if UV is
used after vessels deballast. Shipboard UV treatment of ballast water
during ballasting, before iron from the ballast tanks contaminates the
ballast water, will be unaffected by iron introduced from the ballast
tanks. Shorebased treatment plants, where ballast is treated at the end
of a voyage, will require pre-oxidation and clarification prior to UV
irradiation. Newer vessels and vessels with good corrosion protection,
will not contain such high levels of iron. Ozone is unlikely to be appropriate
for ship board treatment of ballast water, due both to the possibility
of increased corrosion of ballast tanks and the difficulty of maintaining
a disinfection residual in an area high in dissolved iron and areas of
sludge and sediment which are high in organic material.
The results of the sampling indicate that at least 14% of vessels which
reported ballast exchange at sea had either done so ineffectively or failed
to do so. It is possible that up to 57% had exchanged ineffectively, based
on a chemical characterisation process, which compares the composition
of ballast water with what would be expected from oceanic water. Problems
with this type of comparison is re-contamination of the oceanic water
by unexchanged sediments and water remaining in ballast tanks, even after
the exchange process, and the effect that the presence of iron in some
ballast tanks may have on measurements. Additional research is needed
to determine the effectiveness of characterisation as a way of monitoring
the exchange process.
The method used to sample ballast water, and the sample location have
a substantial effect on the measured characteristics of the water collected.
Problems with sampling methods and ways to overcome them are described.
THIS PUBLICATION IS CITED AS:
Oemcke, Darren & van Leeuwen, J. (Hans) (1998)
Chemical and physical characteristics of Ballast Water: Implications
for treatment processes and sampling methods.
Technical Report No. 23
Townsville; CRC Reef Research Centre Ltd, 44 pp.
ISBN 1 876054 87 5
A full copy of this report may be obtained from the author(s),
and through the following libraries:
Agency libraries: Great Barrier Reef Marine Park Authority,
Townsville; Australian Institute of Marine Science, Townsville; James
Cook University, Townsville; Queensland Department of Primary Industries and Fisheries
(Brisbane and regional offices); Queensland Department of Environment
and Heritage (Brisbane and regional offices); CSIRO Division of Marine
Research, Tasmania.
Public libraries: Queensland, New South Wales, Tasmania and South
Australia State libraries; National Library, ACT.
Parliamentary libraries: Queensland, New South Wales and South
Australia parliamentary libraries.
Download a complete copy of the report(Adobe
Acrobat File - 2.63MB)
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