The Great Lakes Ballast Technology Demonstration Project Filtration Mechanical Test Program

Abstract

The Great Lakes Ballast Technology Demonstration Project has investigated the effectiveness of automatic backwash screen filtration of ballast water during its uptake as a means of minimizing the potential for the introduction of nonindigenous species. The Great Lakes Protection Fund; the State of Minnesota, upon the recommendation of the Legislative Commission for Minnesota Resources (LCMR); the LakeCarriers' Association; Northeast-Midwest Institute; Federal agencies and universities have supported this project. Initial testing during the 1997 operating season involved testing onboard the Seaway-sized bulkcarrier MV Algonorth during operations between the Gulf of St. Lawrence and Great Lakes ports. Thistesting provided important information on system design, operations, and filtration biological effectiveness, but the mechanical test results were of limited value as benchmark experiments. During the summer of1998, the modular system was installed on a barge located in the Duluth, Minnesota, harbor to permit more controlled, intensive mechanical and biological testing. The overall design of the shipboard and the bargeballast water filtration test installations are briefly summarized. The barge mechanical test program involved extended testing with 25 micron, 50 micron, and 100 micron filter screens at a nominal 1500 U.S.gpm using an operating profile that approximates normal ship ballast operations. The results of this test program are reported. Lessons learned in the system design, operation, and test program are discussed.