Ballast Water Treatment System (BWTS) is a system designed to remove and destroy/inactive biological organisms (zooplankton, algae, bacteria) from ballast water. Ballast water treatment is still evolving technology with an ever-growing number of manufacturers. This means that there is limited in service experience for the systems being offered and there is a general understanding that no single system is suitable for all ship types.

The Ballast Water Management Convention (BWMC) entered into force on 8 September 2017. This means that an estimated 34,000 ships above 400 gross register tonnes (GRT) will be required to install a type-approved ballast water treatment system at their next mandatory International Oil Pollution Prevention (IOPP) survey to protect local ecosystems around the world.