The National Park Service has been experimenting with methods of treating ballast water to prevent the spread of aquatic invasive species. The National Park Service Ranger III, pictured alongside the Voyageur II at Rock Harbor, Isle Royale, has been the research vessel for this study. Initial tests showed the ballast treatment systems employed were successful.
The National Park Service continues its efforts to prevent the spread of aquatic invasive species. Invasive species such as the zebra mussel have caused extensive damage to natural resources and cost millions of dollars in eradication and control efforts. Ballast water discharges from ships (water used for ship stability) is a primary pathway for introduction of invasive species. The NPS and its partners have conducted significant research into ballast water treatment technology, most recently this summer at Isle Royale National Park.
Results are in from the summer testing of two freshwater ballast treatment systems on the NPS ship Ranger III. The NPS tested a manually operated rapid response treatment process that used chlorine and a neutralizer and a fully automated permanent treatment system using filtration and ultraviolet (UV) technology. The shipboard status tests were conducted in September 2014 and the final report was recently released. Both systems passed United States federal and international standards for two out of three requirements: discharge of living zooplankton and indicator bacteria.
The systems did not meet the standards for phytoplankton, which remain some of the toughest organisms to kill. Since the numbers of live phytoplankton collected exceeded the standard, the test facility conducted a viability analysis. After giving the organisms optimum conditions for growth and reproduction it was determined they were not viable (not capable of reproduction) after undergoing either of the treatments.
More information on results and criteria will be posted on the Isle Royale website, www.nps.gov/isro.
Isle Royale National Park Superintendent Phyllis Green commented: “We are pleased with the performance of the UV system and hope that this system and others will soon pass type approval testing by the U.S. Coast Guard so that automated permanent systems are available for all sizes and classes of freshwater ships. In the meantime, we continue to pursue development and testing of rapid response treatment systems that can be used to reduce risk until permanent systems are installed and functional on 100 percent of ships entering U.S. waters.”
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