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| News :. Shipboard pests get sterile treatment
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Trials have begun on a new water sterilisation system for destroying the exotic marine species that hitchhike to Australia in ships' ballast water and cause environmental devastation.
Researchers from the CRC Reef Research Centre have established a pilot plant to sterilise ballast water from ships in Townsville, as part of a $675,000, three-year project.
The pilot plant uses a combination of filtration, ultraviolet light and sonic disintegration to sterilise water.
There are now over 250 exotic marine species reported in Australian waters. For example, the northern Pacific seastar Asterias amurensis, which reaches plague proportions, was believed to have been introduced to the Derwent estuary in Tasmania via ballast water in the early 1980s and has since spread as far as Port Phillip Bay in Victoria, again by being picked up and transferred in ballast water. The seastar can quickly devastate commercial fisheries and local ecosystems.
Designer of the plant Dr Phil Schneider from the CRC Reef Research Centre says invasion of exotic marine species from ballast water into local ecosystems is "one of the world's most significant environmental problems at this time ... introduced marine pests can disrupt ecosystems by introducing diseases and competing with native species for food and habitat."
"There is an urgent need for an effective and economic method to treat ships ballast water," he says.
The dimensions of the problem are staggering, he says. Even though the need for sterilising this water has been discussed and researched for over a decade, to date there is no effective method to treat ships' ballast water economically.
Schneider believes his system could provide sterilisation on the scale required by the shipping industry, with the eventual aim of developing a ballast treatment system that could be integrated into the ship.
"So far, preliminary trials of our pilot plant have been very successful. The plant has a 12-15 tonnes per hour throughput, which is impressive in terms of laboratory equipment, but only a drop in the ocean when you're looking at the volume of ballast water carried by shipping. Our aim is to develop the pilot plant so that we can scale the technology to serve the world's shipping fleet."
Ships carry 10 billion tonnes of ballast water each year (carried to stabilise a ship when it's not carrying cargo). A single ship can hold 70,000 tonnes of ballast water - enough to fill 32 Olympic swimming pools. This water, which is drawn from the sea, may carry millions of small and microscopic organisms, including the larvae of shellfish and seastars. Many of the species have the potential to become environmental and economic pests.
The current procedure to minimise the risk of spreading pests is to exchange the ballast water while still out in the open ocean before getting near coastal water. Deep water ballast exchange is mandatory for ships from 'high risk' areas coming into Australia. However, these methods are not fully effective as not all the ballast water usually gets exchanged, and the process of emptying the ballast at sea can be dangerous for ships as it places enormous structural strain on the vessel. The process also takes time, extending the travel time of ships. It's estimated that deep water ballast exchange costs the shipping industry over $23 million a year.
The project is funded by CRC Reef Research Centre, James Cook University, the Natural Heritage Trust, Ports Corporation of Queensland, Port of Townsville, Mackay Port Authority, Gladstone Port Authority, Amiad Australia, Pasminco Century Project, Modular Solution Technologies and the Great Barrier Reef Research Foundation. |
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