Ballast water and effluent polishing

Perhaps the next most critical problem man has caused to the World, after global warming, is the devastation caused to many Ecosystems by the inadvertent transport of organisms and bacteria in ships ballast. Really it’s a simple water treatment problem, except that it involves 7000 Million tonnes of water a year, discharged at high flow rates, and it affects the business of some very aggressive and commercial freight transporting operations, in every country of the world.

The story has been told on an excellent BBC/IMO CD, which leaves you wondering why we are allowed to misuse this planet so: see a review of the problem in my report on the recent Alfa Laval PureBallast product launch, or also as detailed in the two recent Alfa Laval press releases. Several organisations come out of this with a lot of credit for their actions: like the London-based IMO, who have imposed world-wide ballast transport regulations, stimulating research into the problem. Like Australia, who took action to eliminate the South American black-striped mussel when it was discovered to have been imported to Darwin harbour: the quarantine and clean-up effort cost Australian taxpayers USD$2Million, but it managed to protect the Australian pearl industry. But in doing so the decision had to be made to close the harbour and use chemical treatments that severely impacted even native species. Almost in reverse, it is perhaps too late now to stop the Chinese ‘Golden Mussels’, which arrived in South America five years ago, and are devastating the fresh water habitat throughout Brazil, heading for the Amazon basin and closing down hydro-electric plants on the way.

Most of the credit for the PureBallast development goes to several Swedish organisations and businessmen, who as a group seem to have the most responsible attitude to such problems. The Wallenius shipping line and group,, pioneered the development that has now been taken up by Alfa Laval, adding the PureBallast water treatment system capability to the many other ship borne bilge water (oil and waste) and sewage discharge treatment systems that they supply.

The PureBallast system uses the action of high intensity broad spectrum light sources on titanium (catalyst) baffles in the bilge water flow, both on intake and discharge, producing hydroxyl ions that oxidise organic matter, viruses, plankton etc. Compact enough for a ship installation, no moving parts, quite a lot of energy consumption, it looks like the answer, and is almost through the necessary several years of testing. The technique is the same as that used for self cleaning windows on sky-scrapers, windscreens etc, that use the power of sunlight on a titanium based film as the catalyst. Once Alfa Laval have perfected this application, it will be interesting to see what the next developments will be in the application of the technology.

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