A report by the Wisconsin Department of Natural Resources (DNR) has determined that ballast water from saltwater ships that enter the Great Lakes could be treated onshore for approximately a $2 million construction cost per facility.
A coordinating feasibility study performed by a Milwaukee-based environmental engineering firm calculated the possibility of transporting ballast water to the on-land treatment plant by barge while the ship was loading bulk cargo.
Roger Larson, deputy watershed management bureau director for the Wisconsin DNR, said of the process, “We tried to make it as convenient as possible, to accompany the loading and unloading process and to make sure it wasn't in the way or taking more time. Nobody had really looked at whether this was feasible. We think we've found that it is."
An onshore treatment system may make ballast water treatment a possibility for smaller ships, that do not have the space or money to include treatment systems on board. It would also make the process easier to monitor.
Ballast water has been blamed for introducing hundreds of exotic species into the Great Lakes, including zebra mussels, spiny water fleas and VHS, a deadly fish disease.
"This is good news in the fight against invasive species," said Matthew Frank, Wisconsin DNR secretary. "Further study and a pilot project still need to be done, but these study results take us one step closer to finding a way to turn off the spigot of invasive species arriving in the Great Lakes via ballast water discharge."
In order to control such invasive species, legislation has been introduced in Congress to mandate ballast water treatment. The legislation has not made any progress so far.
Nonetheless, the attention that is now being paid to ballast water and its effect on the Great Lakes is part of an increasing trend. Lake Superior has already been undergoing a study called the Great Ships Initiative, which is testing on-ship treatment systems by means of a similar, land-based system. The concern is that the on-ship systems are not killing live, and potentially harmful, species in their ballast tanks.
