Pursuant to international regulations, ships must have equipment to treat ballast water and sediments in order to prevent invasive species from spreading to parts of the world where they do not appear naturally. These species can have a destructive or disturbing effect on the ecosystem when they are contained in ballast water from other parts of the world.
Order on the treatment of ballast water and sediments from the ballast water tanks of ships
IMO is the United Nations’ maritime organisation, which has adopted regulations on the protection of the marine environment and the International Convention for the Control and Management of Ships' Ballast Water and Sediments, adopted in 2004. With effect from 13 October 2019, ships must have equipment installed to treat ballast water and sediments, pursuant to international ballast water regulations.
Ballast water for larger ships can be a problem for the marine environment. Worldwide, five to ten billion tons of water are moved each year from one sea to another. This arises when cargo ships empty their enormous tanks of ballast water.
If ballast water and sediments are not treated, various living organisms in the ballast water can spread to ecosystems where they do not belong. This constitutes an environmental problem. The UN convention on ballast water is intended to reduce the spread of introduced invasive species, which, among other things, can cause illnesses and affect fish, ecosystems and bathing water.