A​​s a specialized agency of the United Nations, IMO is the global standard setting authority for the safety, security and environmental performance of international shipping. Its main role is to create a regulatory framework for the shipping industry that is fair and effective, universally adopted and universally implemented.

The IMO adopted the Ballast Water Management Convention in February 2004. It was set to enter into force 12 months after ratification by thirty nations that together represent 35% or more of the world’s total merchant shipping tonnage. This date is now known: Friday the 8th of September 2017.The Convention requires that ballast water must be treated – to specify D2 standards – before it is discharged. All vessels built before the date of entry into force of the BWMC, must install a Type Approved system at the first renewal of the IOPP certificate.

Performance Standard

Regulation D2 Ballast Water Performance Standard Ballast Water Treatment systems approved by the Administration which treat ballast water to an efficacy of:

  • not more than 10 viable organisms per m3 >50 micrometers in minimum dimension, and
  • not more than 10 viable organisms per millilitre < 50 micrometers in minimum dimension and >10 micrometers in minimum dimension.

Indicator microbes, as a human health standard, shall include:


  1. Toxicogenic Vibrio cholerae (O1 and O139) with less than 1 colony forming unit (cfu) per 100 milliliters or less than 1 cfu per 1 gram (wet weight) zooplankton samples.
  2. Escherichia coli less than 250 cfu per 100 milliliters.
  3. Intestinal Enterococci less than 100 cfu per 100 millilitres.