What are D1 and D2 standards of ballast water management?
The D1 and D2 standards are part of the Ballast Water Management Convention (BWMC), which is an international treaty adopted by the International Maritime Organization (IMO) to address the control and management of ballast water to prevent the spread of harmful aquatic organisms and pathogens.
- D1 Standard: The D1 standard of the BWMC relates to ballast water exchange. It specifies the requirements for conducting ballast water exchange, also known as “open-ocean exchange.” Ballast water exchange involves replacing ballast water taken on in one location with water from the open ocean, typically beyond 200 nautical miles from the nearest land and in waters of sufficient depth. The purpose of D1 is to minimize the number of living organisms carried in ballast water.
- D2 Standard: The D2 standard of the BWMC sets the requirements for ballast water treatment systems. It specifies the performance criteria for such systems to ensure that they effectively treat ballast water to remove or kill organisms and pathogens. Ballast water treatment systems must meet the criteria outlined in the D2 standard to be considered compliant with the convention.
The Ballast Water Management Convention entered into force on September 8, 2017. However, the requirements for compliance with the D2 standard of ballast water treatment systems were phased in over a period of time based on the ship’s International Oil Pollution Prevention (IOPP) renewal survey schedule. The specific deadlines for compliance with the D2 standard depend on the ship’s construction date:
For new ships: New ships constructed on or after September 8, 2017, are required to comply with the D2 standard at the time of delivery.
For existing ships: Existing ships (those constructed before September 8, 2017) are required to comply with the D2 standard at the time of their first IOPP renewal survey that occurs after September 8, 2019. This means that existing ships needed to install and operate ballast water treatment systems by the time of their first IOPP renewal survey after the specified date.
The specific compliance deadlines may vary depending on the ship’s individual circumstances and survey schedule, but the goal of the BWMC is to ensure that all ships eventually meet the D2 standard to minimize the environmental impact of ballast water discharge. Shipowners and operators are encouraged to consult with relevant authorities and organizations to understand and meet the compliance requirements of the BWMC.