Today, maritime traffic represents 90 percent of the world's freight and consumes as much as five billion tons of ballast water annually – a figure that is expected to increase three-fold within 10 to 15 years.
Organisms are transported with this water and, when tanks are emptied, these multiply and risk disrupting natural ecosystems. A current example is the comb jellyfish, which, although originally from the Atlantic coast of North America, is now spreading rapidly in the Baltic. In the Black Sea, it has already had a devastating impact on fishing.
The transfer of ballast water between the world's oceans and sensitive marine ecosystems has become one of the greatest environmental threats of modern times. For this reason, the International Maritime Organization (IMO) has adopted a convention requiring that merchant vessels introduce a system for handling and purifying ballast water. The tough IMO requirements mean, for example, that the number of living organisms larger than 50 μm must be reduced to fewer than 10 organisms per m³. There are also separate requirements set up for organisms between 10μm and 50μm as well as for a few indicator bacteria species.However, the convention will not come into force until at least 30 of the states representing 35% of the world merchant shipping tonnage have signed it. Currently (March 2010), 22 states, representing 22,65% have ratified the convention. Without the convention, most ship owners see no reason to purify their ballast water, even though solutions are available.
The world's first chemical-free ballast water purification system is Swedish
Together, Wallenius Water and Alfa Laval have developed the PureBallast water purification system, the first chemical-free method for purifying ballast water to have gained the full approval of the independent global certification organisation Det Norske Veritas and the UN's International Maritime Organization.
The heart of the PureBallast system is Wallenius AOT and the approval demonstrates that our technology for chemical-free water purification actually resolves major environmental issues that arise when microorganisms are transported and released with ballast water. PureBallast has also received awards from the World Wildlife Fund (WWF), Seatrade and the Swedish Maritime Forum. PureBallast is marketed and sold by Alfa Laval.