All vessels must meet the D2 standard by 8 September 2024.
IMO D2 commissioning testing is carried out to confirm that the installation of the BWTS was successfully performed. It validates that the mechanical, physical, chemical and biological processes of the BWTS are working correctly according to the design specifications.
A biological test for D2 standards is only required in the commissioning phase and before the International BWM Certificate is issued. As of June 1st 2022, commissioning sampling is compulsory and cannot be organised by the maker. As per regulations, analyses should be performed on Total heterotrophic bacteria, E. Coli and Enterococci.
As per BWM Convention (BWM.2/Circ.70/Rev.1), validation is successful if the sample does not exceed D2 standards and the self-monitoring equipment indicates correct operation. The regulation requires ships to comply with the following:
Table 1 summarizes the limits for the indicators in the ballast discharge according to the D2 standards:
| Parameter | Limit |
| Organisms ≧ 50 µm (e.g., zooplankton) | <10 viable organisms/m3 |
| Organisms ≧ 10 µm and <50 µm (e.g., phytoplankton) | <10 viable organisms/mL |
| Enterococci | <100 cfu/100 mL |
| Escherichia coli | <250 cfu/100 mL |
| Vibrio cholerae | < 1 cfu/ 100 mL |
Table 1. IMO D2 Parameters
Most flag states require indicative water sampling on board the vessel, therefore laboratory testing is not necessary unless the water fails the onboard indicative sampling. The current exception to this rule is for Cyprus flag that requires the laboratory test as part of the commissioning process.
In case the testing fails, the potential causes must be analysed and the test repeated in another port.
According to the current rules and regulations, there is no requirement for annual D2 sampling. It could be introduced in the future.
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D2 commissioning sampling is essential for BWMS as it ensures compliance with international standards, validates treatment efficacy, and verifies system performance. IMO establishes strict rules for treating ballast discharge to prevent the spread of harmful organisms from shipping activities. Commissioning sampling allows for the verification of the BWMS’s treatment effectiveness and its adherence to discharge standards. Commissioning sampling provides evidence of compliance, ensuring ships meet regulatory requirements and avoid penalties. By conducting sampling during the commissioning process, BWMS can be properly calibrated, ensuring the removal of harmful organisms. IMO D2 commissioning sampling reduces the adverse environmental effects of ballast discharge in the global waters.
It is recommended to regularly check the quality of your ballast water to avoid problems with Port State inspectors.
Vessels sailing to US require USCG-approved BWTS.
During the first year, water needs to be tested between 2 to 4 times. If sampling results are below permit limits for two consecutive events, then sampling may be reduced to one time per year.
If the vessel exceeds the limits, it should return to monitoring twice a year. Analyses should be made on Total heterotrophic bacteria, E. Coli and Enterococci. Compliance with these VGP requirements is administered by the EPA which requires that tests are carried out according to their specific regulation.
An accredited technician will take the necessary samples and analyse them for organisms, according to the IMO BWM.2/Circ.70/Rev.1 and G2 standards.
D2 commissioning sampling can be performed upon request in combination with VGP testing. We recommend doing both sampling tests at once since it will be more time-saving, cost-efficient and will have the added value of satisfying both regulatory requirements at the same time. Performing both in one go can only prove beneficial for shipowners and managers and has virtually no drawbacks. With our network, we can assist you in your next port of call! We have a worldwide presence, from USA to United Arab Emirates. With the main office in Rotterdam, we developed a global network of technicians and laboratories.
With our team, you receive:
Note: IMO D2 sampling must be carried out by a certified third party. This may no longer be carried out by the manufacturer.
Plan your D2 Commissioning sampling. Contact our team here.
For additional information, also visit our pages:
Installation and Commissioning
D2 Commissioning Testing – All you need to know
You can also find and submit your service request to Mr. Marine Ballast on:
ShipServ: TN-311092 – Mr. Marine Ballast
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