Exchange of Ballast Water at Sea and Onboard Treatment

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Contents

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The environmental problem

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Ballast water exchange

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The transition to ballast water treatment onboard

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Systems’ installation criteria

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Current technologies Mediterranean Marine Environmental Awareness Course

Ballast water is important for a vessel’s stability and her structural integrity in the ballasted condition

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The scale of the problem

The problem of marine invasive species is nothing new. For hundreds of years, species have traveled around the world through international shipping via ballast water and bio-fouling and in other ways having the same effect such as aquaculture and canals.

The scale of the problem

Round Goby Dinoflagellate Gymnodium catenatum Dreissena Polymorpha Asterias Amurensis Vibrio Cholerae

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Mnemiopsis leidyi

Zebra Mussel was introduced in lake St. Claire in 1991 and within 10 years has been expanded to all Great Lakes of the United States.

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Source: ISSG

In February 2004, the International Maritime Organization adopted the International Convention for the Control and Management of Ships Ballast Water and Sediments aiming to prevent and minimize the risks to the environment, to human health, property and resources caused by the transfer of marine invasive species

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BWM Standards

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Exchange Standard: D-1 Performance Standard: D-2

• • Sequential method with at least 95% volumetric exchange Flow-through method with at least three times volumetric exchange • Number of viable organisms of a certain size … • Less than 10 viable organisms per 1 m³ greater than 50  m • Less than 10 viable organisms per 1 ml smaller than 50  m and greater than 10  m • Limited number of indicator microbes  1 CFU Vibrio cholera per 100 ml  250 CFU eschericia coli per 100 ml  100 CFU enterocci per 100 ml

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Ballast Water Exchange

Ballast Water Exchange should be undertaken: • at least 200 nm from the nearest land and in water at least 200 m in depth, or if not possible • at 50 nm and 200 m depth, or if not possible • in areas designated by the Port State • Neither deviation nor delay of the ship shall be required and exchange should only be undertaken when safety of the ship is guaranteed

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Plans & Documents on Board

Each ship shall have on board a:  Ballast Water Management Plan (approved)  Ballast Water Record Book

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Sequential method

BW Exchange Methods

Initial quantity of ballast Empty tank Insert new ballast Flow-through method Initial quantity of ballast 1 st exchange 2 nd exchange 3 rd exchange

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How effective is ballast water exchange?

 The need for prompt action and control of the introduction of unwanted marine species, required the maritime industry to adopt Ballast water exchange methods without any previous efficiency tests.

 Studies of exchange method’s efficiency with the help of pigments has shown that, a small percentage of these organisms remain at ballast tanks, which under certain circumstances may survive.

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• • • • •

How effective is ballast water exchange?

Some vessels accumulate tonnes of sediments that contain their own living organisms.

Great concern is the transfer of phytoplankton cysts in sediments from ships: 65% out of 343 ships inspected in Australia were found with these sediments.

BWE may provide additional oxygen and food to organisms that remain in the ballast tank.

It is considered to be more effective when there is a big difference in salinity.

MEPC 46/3 2000: ΙΜΟ characterize BW Exchange as a temporary measure and brings forward ballast water treatment as an alternative solution to the problem, a solution possibly more effective and safe.

Sediment accumulation in a double botton tank

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How effective is ballast water exchange?

In the period of 1996 – 1997 surveys have been conducted on container ships that travelled from Oakland, California, Kobe and Yokohama in Japan, with final destination in Hong Kong, a trip that lasted 16 days.

On average, the abundance of harmful plant organisms measured on board at the port of destination after ballast exchange was reduced by 87% compared with the ships that arrived with the original ballast (from 4235 to 550 organisms per liter ballast).

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Ballast water management timetable

Res. A.1005 (25

)

Ratification status:

Requested: 30/35) 33 countries and 26,46% of world tonnage (per March 2012.

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Onboard ballast water treatment

An example of a process cycle with a) treatment upon ballasting and b) neutralization of treated ballast water upon de- ballasting

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Installation criteria of a ballast water treatment system

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Current Technologies

Filtration

Environmentally friendly treatment technique of ballast water.

1 st phase of many treatment systems in order to retain the larger organisms and solid particles.

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Current Technologies

Hydrocyclones

Separate solid particles from water using centrifugal forces. Effective for organisms > 50 micrometers.

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Current Technologies

Ultraviolet radiation

Affixed to the outer membrane of organisms and destroys the cell structure. The effectiveness of this method depends on the turbidity of the ballast and the arrangement of UV radiation tubes.

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Current Technologies

Addition of stored chemicals

They are dosed to ballast water to kill organisms (chlorine gas, chlorine dioxide, sodium hypochlorite and ozone).

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Current Technologies

Deoxygenation

Remove the dissolved oxygen in the ballast and replaces it with inert gas, usually nitrogen. Eliminates the aerobic bacteria and helps prevent corrosion of the tanks.

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Current Technologies

Cavitation

With the help of hydrodynamic forces or ultrasonic waves the cell walls are effectively destroyed.

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Current Technologies

Electrolytic Chlorination

Electric current is applied directly to the ballast in electrolytic cells, producing chlorine as the major active substance and other chemical compounds.

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Number of approved ballast water treatment systems

 About 2/3 of all technologies make use of active substances  Around. 20 type approved systems are currently available (forecast end of 2012: > 30)

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Estimated number of vessels which need to be fitted with BW treatment systems in the near future

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Thank you for your attention!

Questions

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