Every year ships carry an estimated 5 to 10 billion tons of ballast water in order to provide ships with the draught and stability needed. However, ballast water also contains “alien” invasive species which can destroy local fauna and flora and, as such, threaten the oceans’ biodiversity.
To control the problem, IMO signed the 2004 Ballast Water Management Convention.
As some countries recently ratified the Convention, the required 35% of the world tonnage has been met and consequently the Convention will enter into force in September 2017.
In the BWM-Convention port reception facilities for ballast water and sediments are mentioned. As sediment disposal will be carried out at shipyards during a vessel’s 5-year survey, reception facilities for sediments (mostly very fine material with an high water content) should be provided.
Ships not succeeding in effectively treating ballast water or not changing ballast water due to weather conditions or other circumstances can keep the non-compliant ballast water on board, can pump it to another ship or can deliver it to an IMO-approved port reception facility.