Arctic Shipping
The Canadian Ballast Water Program
A vessel manages ballast water if it discharges it at a reception facility, retains it on board, performs a ballast water exchange, or uses a treatment process. Ships that navigate more than 200 nautical miles from shore in waters with a depth greater than 2 km must perform a ballast exchange in waters that are at least 200 nautical miles from shore with a depth greater than 2 km . Ships that do not navigate in those areas must perform the ballast water exchange in waters that are at least 50 nautical miles from shore with a depth greater than 500 metres. If performing a ballast water exchange in those areas is not possible because it will compromise the safety of the ship or people on board, two alternate sites have been designated in the Arctic. Vessels proceeding to Hudson Bay ports can perform ballast exchanges in the Hudson Strait in areas that are east of 70° west longitude and have depths at least 300 metres. Vessels proceeding to Higher Arctic ports can perform ballast exchanges in Lancaster Sound in areas that are east of 80° west longitude and have depths at least 300 metres.
Freezing Ballast Water
The very cold environment of the Arctic could cause the ballast water, air and vent pipes, valves and section lines to freeze. If ice chunks fall from the tank sides after the discharge of the liquid ballast, they may damage coatings or components. It is unlikely that any sizeable tank will freeze solid since ice acts as an insulator; however, ice can not be discharged when the vessel is loading and causes the deadweight capacity to be reduced.
Ballast water in tanks above the waterline in vessels may freeze starting from the top of the tank and at the sides. The extent of the freezing will depend on the salinity of the ballast water and the temperatures encountered. Higher salinity water should be used as fresh and brackish water freezes more easily than high salinity water. The type of water used will depend on local and regional environmental regulations along the route.
To reduce the risk of ballast water from freezing, minimize the amount of ballast water that is carried high in the vessel. Placing the seawater systems low in the vessel and away from ice flow lines, having some way to separate ice from the water while pumping in water, and re-circulating hot water from cooling systems into the inlet areas helps prevent freezing in the system and from ice entering the tank. Bubble systems help prevent freezing and can be used in temperatures as low as –30° C . Heating coils are another way to prevent ballast water from freezing. It is also advisable to provide heating or water re-circulation to deal with possible freeze-up and associated problems during start up.
Regulations
There have been other developments at the international level directed at replacing the exchange procedure by a treatment approach. As of February 13, 2004, the International Maritime Organization adopted the International Convention for the Control and Management of Ship’s Ballast Water and Sediments. This Convention, which now awaits ratification, calls for adoption of prescribed standards over a seven-year period from 2009 to 2016.
Control of ballast water in Canada is governed by the Ballast Water Control and Management Regulations, under the Canada Shipping Act 2001 and guidelines for ballast management are found in A Guide to Canada’s Ballast Water Control and Management Regulations (2007) - TP 13617.