- where neither, form of open ocean exchange is practicable, ballast exchange may be accepted by the port State in designated areas; and
- other ballast exchange options approved by the port State.
9.2.2 Non-release or minimal release of ballast water
In cases where ballast exchange or other treatment options are not possible, ballast water may be retained in tanks or holds. Should this not be possible, the ship should only discharge the minimum essential amount of ballast water in accordance with port States' contingency strategies.
9.2.3 Discharge to reception facilities
If reception facilities for ballast water and/or sediments are provided by a port State, they should, where appropriate, be utilized.
9.2.4 Emergent and new technologies and treatments
9.2.4.1 If suitable new and emergent treatments and technologies prove viable, these may substitute for, or be used in conjunction with, current options. Such treatments could include thermal methods, filtration, disinfection including ultraviolet light, and other such means acceptable to the port State.
9.2.4.2 Results concerning the application and effectiveness of new ballast water management technologies and associated control equipment should be notified to the Organization with a view to evaluation and incorporation, as appropriate, into these Guidelines.
10 Port State considerations
The following is provided for the guidance of port State authorities in the implementation of their ballast water management programme, and to assess risks in relation to the ballast water containing harmful aquatic organisms and pathogens.
10.1 Highly disparate conditions between uptake and discharge ports
Significantly different conditions may exist between port(s) of origin and the port in which ballast water is discharged. Examples include fleshwater ballast being released into highly saline ports. There may be organisms capable of survimg such extreme transfers; however, there is a lower probability of species establishment under such transport events.
10.2 Ballast water age
The length of time during which ballast water is within an enclosed ballast tank may also be a factor in determining the number of surviving organisms, because of the absence of light, decreasing nutrients and oxygen, changes of salinity and other factors. However, the maximum length of survival of organisims in ballast water varies, and in many cases is not known. Water of an age of 100 days should be considered the minimum for applying this consideration. Ballast water and sediments may contain dinoflagellate cysts and other organisms capable of surviving for a much longer length of time.
