Ballast Water Treatment Technologies and Their Application for Vessels Entering the Great Lakes via the St. Lawrence Seaway

1 review of the current status of ballast water treatment technologies since 1996 when the National Research Council's Stemming the Tide was published, and major impediments to the implementation of these technologies on a large scale, are presented. In addition, factors that affect implementation of the technologies on ocean-going vessels transiting in the St. Lawrence Seaway and the Great Lakes are identified. From the survey of peer-reviewed literature, many of the studies have focused on filtration/physical removal systems, biocides (oxidizing and non-oxidizing), or a combination of technologies, most often filtration/physical removal systems followed by organism inactivation via biocides or ultraviolet (UV) light. One major impediment to the implementation of technologies has now been resolved, with the establishment by the International Maritime Organization (IMO) in 2004, of ballast water discharge standards. Also underway is a joint effort by the US Environmental Protection Agency, NSF International, Battelle and the US Coast Guard to develop protocols and identify standard conditions for pilot-scale testing of ballast water treatment technologies. Once these procedures and standard conditions are well-defined and are in place, it is expected that progress on developing ballast water treatment technologies will accelerate. For ocean-going ships operating on the Great Lakes, the unique nature and configuration of vessels transiting the area (e.g., under No Ballast on Board, or NOBOB status), and physical/chemical water characteristics, pose challenges to the effectiveness of certain treatment options. Overall, given the current scientific and engineering knowledge base, and the fact that the Great Lakes serves as a drinking water source for 33 million people, it appears that a treatment technology capable of reliably achieving treatment standards is the most suitable system for ocean-going vessels operating on the Great Lakes. This infers that other often cited criteria such as cost and ease of operation should be secondary considerations for technology selection on these vessels. In addition, focus for effective treatment systems should be shifted to new ships being built for use in the Seaway.