Ballast Water Treatment System
A Ballast Water Treatment System (BWTS) treats the ballast water a ship takes on and discharges, to kill or remove the aquatic organisms and pathogens it contains, so that they are not carried and released into another marine environment. Common methods combine filtration with ultraviolet treatment or with electrochlorination.
A BWTS is required under the IMO Ballast Water Management Convention, which sets a discharge standard for the number of living organisms allowed. Ships must have a type-approved system, keep records, and meet the standard on every ballast discharge — a major retrofit and operational requirement across the world fleet.
Ballast water has spread invasive species around the world, causing serious ecological and economic damage, which is why the Ballast Water Management Convention now requires treatment. A compliant BWTS is a legal must-have; failing to meet the standard risks detention and port-entry refusal.
Why must ballast water be treated?
To prevent the transfer of invasive aquatic species and pathogens from one region to another. The Ballast Water Management Convention sets a standard for living organisms that a treatment system must meet before discharge.