Why there is a need to manage the ballast water?
While ballast water is essential for safe and efficient modern shipping operations, it may pose serious ecological, economic, and health problems due to the multitude of marine species carried in ships’ ballast water. The transferred species may survive to establish a reproductive population in the host environment, becoming invasive, out-competing native species and multiplying into pest proportions. The effects in many areas of the world have been devastating
Ballast Water Standards
There are two types of ballast water standards in the convention. Their differences are significant and they should not be directly compared.
The first, Ballast Water Exchange, is based on specified distances and depths where a vessel may discharge.
Ballast Water Performance is a standard based on the number of viable organisms allowed per unit of treated water.
Some areas are instituting standards which exceed the IMO guidelines. Both California and the Great Lakes region of the United States have adopted stringent local guidelines.
Different types of Ballast water exchange
Before entering into the waters of any coastal state, ballast water exchange has to be done in mid-ocean or at least 200 nautical miles from shore and at a location where the water depth is at least 200 meters or more.
If neither of these scenarios is possible then a vessel may exchange “in an area designated by the port state”. While undertaking ballast water exchange a port state must not cause deviation or delay of a ship.
The efficiency of exchange should be at least 95% of volume and must be repeated three times. Vessels that demonstrate high-efficiency exchanges may reduce the number of exchange cycles.
Ballast Water Exchange should only be undertaken when the safety of the vessel and crew are guaranteed.
There are three different methods of ballast water exchange: