Ballastvand

Ballastvand, or ballast water, is water taken into ballast tanks on ships to provide stability, trim, and draft control when the vessel is not fully loaded with cargo. It is drawn from the surrounding marine or freshwater environment and discharged at port or another location to return the ship to its proper balance.

The water may contain a variety of living organisms, including plankton, larvae, bacteria, and viruses, as well as chemical contaminants. If ballast water is released in a different ecosystem, these organisms can become invasive, potentially altering habitats, displacing native species, and introducing diseases. The risk depends on factors such as the origin and destination waters, as well as the survival conditions during transport.

Regulatory framework and management practices have been established to reduce these risks. The International Maritime Organization’s Ballast Water Management Convention requires ships to manage ballast water through plans, procedures, and equipment. Most ships must install ballast water management systems (BWMS) that treat ballast water to kill or remove organisms before discharge. In the interim, some vessels perform ballast water exchange in open sea to minimize the load of coastal organisms.

Treatment technologies used in BWMS commonly combine physical methods (filtration, UV irradiation, heating) with chemical disinfection. Implementation varies by vessel type and region, and ships must maintain records and undergo inspections to verify compliance.

Overall, ballast water management aims to prevent the unintentional transfer of aquatic species while maintaining vessel safety and efficiency. Ongoing research and monitoring continue to improve treatment effectiveness and reduce ecological impacts.