The Great Ships Initiative (GSI) provides independent, no-cost performance verification testing
services to developers of ballast water treatment systems (BWTSs) and processes at a purposebuilt,
land-based ballast treatment test facility located in the Duluth-Superior Harbor of Lake
Superior (Superior, WI). The GSI is capable of performing testing fully consistent with the
requirements of the International Maritime Organization’s (IMO’s) International Convention for
the Control and Management of Ships Ballast Water and Sediments (IMO, 2004) and the United
States Environmental Protection Agency’s (USEPA’s) Environmental Technology Verification
Program (ETV; NSF International, 2010). GSI procedures, methods, materials and findings are
also publicly accessible on the GSI website (www.greatshipsinitiative.org).
In July 2010, GSI conducted a land-based performance evaluation test of a proposed BWTS
developed by researchers from the U.S. Geological Survey’s Leetown Science Center in
Kearneysville, West Virginia. The proposed system involved application of sodium hydroxide
(NaOH, in the same formulation used for lye or caustic soda) to ballast water to raise pH,
followed by application of carbon dioxide (CO2) as a neutralization step prior to discharge of the
ballast water to the receiving system. The purpose of the land-based test of this system,
consisting of four trials, was status testing for research and development. As such, the testing
was based on, though not strictly consistent with, the IMO’s G8 Guidelines for Approval of
Ballast Water Management Systems (IMO, 2008a), the IMO’s G9 Guidelines for Approval of
Ballast Water Management Systems that make use of Active Substances (IMO, 2008b), and the
USEPA’s ETV Program Generic Protocol for the Verification of Ballast Water Treatment
Technology, v.5.1 (NSF International, 2010).
During the test, the NaOH BWTS was evaluated for its ability to: (a) successfully treat ballast
water without interruption, (b) successfully neutralize treated ballast water to achieve Wisconsin
Department of Natural Resources (WIDNR) permitting levels for harbor discharge (i.e., pH 6-9),
(c) meet discharge target values for water chemistry/quality and biology that are approximately
consistent with the IMO Convention’s Annex D-2 discharge standards, and (d) discharge water
after two- or three-day retention periods that is environmentally benign (i.e., no residual toxicity)
pursuant to USEPA water quality criteria. The NaOH BWTS performed very well operationally and well enough biologically to warrant
additional testing at the bench, land and ship-based scales. The system successfully treated
ballast water without interruption, and successfully neutralized treated ballast water to achieve
WIDNR permitting levels for harbor discharge (i.e., pH 6-9). The BWTS also significantly
reduced live organism densities in treated discharge relative to control discharge in all size
classes of organisms. Finally, in these tests, the BWTS performance met discharge target values
that were approximately consistent with the IMO Convention’s Annex D-2 discharge standards,
though precision in this estimate was not possible given the research and development testing
parameters. The only possible problem that this testing revealed was that the water discharged
after two- or three-day retention periods was not entirely environmentally benign (i.e., with no
residual toxicity at the 100 % effluent dilution), though the level of residual toxicity in 100 %
effluent evident from these tests may not be of regulatory concern.
Final Report of the Land-Based, Freshwater Testing of the Lye (NaOH) Ballast Water Treatment System.
University of Minnesota Duluth.
Retrieved from the University of Minnesota Digital Conservancy,
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