What happens during a ballast water exchange?
During an exchange, the ballast water is “exhanged” for “open ocean salt water.” The scientific theory behind exchange is that the fresh water environment is inhospitable for most oceanic organism that are discharged into the Great Lakes. There are two approaches to the exchange. The first is to pump out a tank until it is empty and then refill it with ocean water. The second is to flush out the tanks by bringing in ocean water until sufficient water has been changed.
