Ballast water management (BWM) and biofouling


Ballast water contains a variety of organisms, such as marine and coastal plants and animals from different regions of the world. If taken up in one place and released in another, some organisms may survive and establish in their new environment. These “non-native species” can have a serious ecological, economic and public health impact on the receiving environment. To combat the problem of invasive species from ballast water, the IMO adopted the International Convention for the Control and Management of Ships’ Ballast Water and Sediments in 2004. On 8 September 2017, the Convention entered into force.

Implementation of the IMO convention

The BWM Convention stipulates two standards for discharged ballast water. The D-1 standard covers ballast water exchange while the D-2 standard covers ballast water treatment. D-1 has been mandatory since 8 September 2018. After the first IOPP renewal survey after 8 September 2019*, vessels will be required to meet the discharge standard D-2 by installing an approved Ballast Water Management System (BWMS). New ships will be required to have a treatment system installed at delivery.

*The renewal survey is the survey according to regulation E-1.2 of the BWM Convention, which is defined as the date of the renewal survey according to MARPOL Annex I, Reg. 6.2 (IOPP) by a separate resolution.

IMO Requirements

For ship owners and operators, this means that they must now have an International BWM Certificate.

To obtain the certificate, a vessel must have a BWM Plan addressing procedures for BW exchange, BW treatment or both. If a BWM System is installed, then approved technical documentation for the BW treatment system installation must be available on board. Additionally, a Ballast Water record book is required, and the vessel must employ the chosen ballast water management method.

A commissioining test shall be arranged to verify if the ballast water discharge meets the D-2 discharge standard. Sampling and analysis shall follow BWM.2/Circ.70/Rev.1.

USCG Regulations

Besides the IMO convention, ships sailing in US waters are required to employ a BWMS type-approved in accordance with USCG regulations. DNV has extensive experience in type approval of BWMS for the IMO and the USCG and offer services in this respect.

We at DNV are committed to ensure a smooth transition into compliance with the requirements of the regulations and are ready to guide the ship owners, BWMS manufacturers, yards and designers. Please also visit our Frequently Asked Questions page for further details.


BWM Plan Generator (customers only)

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BWM plan template for D-1

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Biofouling Management Plan Generator (customers only)

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Biological testing at commissioning of BWM

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IMO on Ballast Water Management

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BWM Plan template for D2

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IMO guidelines for Biofouling Management

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