IMO works on industry circular to allow vessels to better deal with muddy ballast water

Member states sending delegates to the next marine environment protection committee of the IMO are working on a text to explain how vessels loading ballast water in ports with difficult water qualities could be allowed to perform ballast water exchange in open waters.

The consideration comes with the realisation that the Ballast Water convention – which industry has struggled with since its agreement in 2004 – has two requirement that create confusion. Under the rules there is the expectation that vessels perform ballast water exchange or treatment. Unfortunately, there is confusion over the legal ability to do both. The convention text does not allow the discharge of unsuitable ballast water into the high seas (through flow-through or ballast water exchange) apart from certain exceptions.

The need for clarification comes when some vessels have to load ballast water while discharging cargoes in ports with muddy silty water and where the treatment system does not fully deal with the organisms within.

A draft IMO circular is being proposed to make such exchange possible. The draft text (before approval at MEPC 76 in June 2021) states:


 “The Committee recommends that, in the case of entry into a port area where certain water qualities, such as high level of turbidity, high level of total suspended solids or low salinity, are identified to exceed the operational limitation of a ship’s ballast water management system (BWMS) or proper operation of the BWMS is not possible and if there is no available reception facility or port-based treatment system, the ship:

.1 may intake ballast water bypassing the BWMS and then move to an area where the BWMS can be operated properly to exchange ballast water in accordance with Guidelines (G6) using water treated by BWMS installed on board to comply with regulation D-2; and

.2 should record the uptake of ballast water and the subsequent ballast water exchange (BWE) plus ballast water treatment (BWT) operations in the ballast water record book and should discharge ballast water in accordance with the method determined by the port State of the next port of call.

3 Regarding paragraph 2.1 above, the ballast water exchange area may be divided into two options:

  .1 Option 1 refers to a method of exchanging ballast water which was not fully treated, with seawater taken in the high seas at least 200 nautical miles from the nearest land and in water at least 200 metres in depth.

  .2 Option 2 refers to cases where the ship is unable to conduct BWE in accordance with Option 1, BWE should be conducted in designated areas for ballast water exchange established by the port State at the next port in accordance with regulation B-4.2; and in case no area has been designated, then as far from the nearest land as possible, and in all cases at least 50 nautical miles from the nearest land and in water at least 200 metres in depth”.

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