Ballast Water Management Convention enters into force on 8 September 2017

The BWM Convention was ratified by a sufficient number of states on 8 September 2016, bringing the total gross tonnage to over 35% from the signatory states. This means the convention will enter into force 12 months later, on 8 September 2017. This news describes consequences for the shipping industry and recommendations to ship owners.


Relevant for owners/managers, BWTS suppliers, shipyards, retrofit design offices, flag states.

The overall purpose of the BWM Convention is to prevent the transport of invasive species from port/area A to port/area B  and thus prevent the destruction of marine habitats.

The BWMC requires each relevant vessel to carry an International BWM Certificate, issued by the flag state. For a majority of flags, DNV GL is delegated to issue such a certificate on their behalf. The vessel shall have this certificate on board by 8 September 2017 at the latest. DNV GL will start issuing (if delegated) such international certificates – provided that an initial survey has been completed – from the beginning of October 2016, even if they are not formally valid, until 8 September 2017.

The BWM Convention includes a transitional period during which ballast water can be “exchanged” in deep seas during voyages between ports A and B. The BWM Plan shall describe how this is done.

Eventually all relevant vessels shall have installed a Ballast Water Treatment System (BWTS), whereby ballast water discharged is made harmless related to invasive species. The IMO implementation schedule for BWTS implies “first IOPP renewal survey after the entry into force of the Convention” at the latest.

This implies that most vessels (which do not already have a BWTS installed) will be requested to install such equipment in the period 2017–2021 – in each case before the expiry date of the vessel’s IOPP certificate. On a ship level, see details of the implementation scheme by clicking on the second link below.

  • The following are prerequisites for issuing an International BWM Certificate:
  • Approved BWM Plan (exchange, treatment or both)
  • Approved technical documentation for a BWTS installation (if treatment system is installed)
  • BWTS Operation Manual (if BWTS is installed)
  • Initial survey for exchange and/or treatment

DNV GL vessels with a voluntary Statement of Compliance for BWM, or a voluntary class notation BWM-E/BWM-T, have already fulfilled these prerequisites. When DNV GL is delegated by the flag administration, the process of issuing the International BWM Certificate will be smooth.

For shipowners in the process of creating a BWM Plan, DNV GL has a helpful template that can be found at

DNV GL also has advisory services for the selection of the BWTS, for retrofit installations and for the creation of a BWM Plan. Please contact your nearest DNV GL office for guidance.


Ship owners should ensure an approved BWM Plan is on board each of their vessels. They should also make sure that the plan is stamped “Approved” (not examined) by the flag or a recognized organization (DNV GL as RO). 

In addition, ship owners should start as early as possible with the planning, selection and installation of a BWTS for each relevant vessel – either owned or managed.

Ship owners should also ensure that any BWTS installed is used for all ballasting and deballasting operations, preferably from the moment it is installed, but at least from 8 September 2017 and onwards. 

For vessels flying a flag which has not yet signed the BWM Convention, ship owners should carry an approved BWM Plan anyway as a ticket to trading internationally.



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