DULUTH, Minn. (AP) — Researchers have conducted a large-scale test of a new
system to kill invasive species hiding in the ballast water of Great Lakes
freighters and expect to get test results back next month.
Crews recently pumped lye into two of 10 ballast tanks inside the 1,000-foot
Indiana Harbor as it left Gary, Ind., treating 1.8 million gallons of
ballast water. The chemical then was neutralized with carbon dioxide as the
boat traveled across Lake Superior before releasing the ballast water in the
The Duluth News Tribune reported Tuesday it’s believed to be the first such
major-scale test on the Great Lakes, with researchers from multiple
universities and federal agencies involved along with funding from multiple
state and federal grants.
The issue is important because state and federal governments are moving to
require ballast treatment to help stop invasive species such as zebra
mussels and nonnative fish, which cause an estimated $5.9 billion in damage
to the Great Lakes every year. More than 60 percent of invasive species
introduced in the Great Lakes have come from ballast water discharged by
“The good news is that we were successful in delivering the biocide at this
huge level for a 1,000-foot laker, then successfully delivered the
neutralizer, all while the Indiana Harbor was on the job,” Phyllis Green,
superintendent of Isle Royale National Park and the instigator of the
effort, told the News Tribune.
Lye, also known as sodium hydroxide, raises the pH of water to kill
organisms. It is commonly used in wastewater treatment plants but had not
been used in major ballast water applications before. Crews then neutralized
the chemical with carbon dioxide so it wouldn’t keep killing when the
ballast water was released.
“We hope to prototype it all the way to full size, all 10 tanks, very
quickly,” Green said.
Green praised American Steamship Co. for offering the Indiana Harbor for the
tests, calling the company a leader in the effort to curb invasives. The
effort required installing more than a half-mile of tubes on the boat, and
researchers welded treatment equipment to the boat for the tests.
“As stakeholders in both the economic and environmental health of the Great
Lakes region, we feel an obligation to support efforts to combat the
detrimental effect of invasive species brought in by oceangoing ships,” Noel
Bassett, vice president of American Steamship Co., said in a statement.
The Superior, Wis.-based Great Ships Initiative now is testing water samples
drawn from the ballast tanks to see if the chemical indeed killed organisms
and whether the treated water was then successfully neutralized to prevent
environmental harm. Results should be available next month.
Barnaby Watten, a senior scientist with the U.S. Geological Survey, said
earlier shore-station testing at the Great Ships Initiative facility in
Superior reached a 98 percent kill rate for living organisms in the water,
with most perishing within 2 hours of exposure to sodium hydroxide.
“We’re hoping to get similar results in real world conditions,” Watten said
in a statement. “But this trial demonstrated the feasibility of our process,
and we are on target with equipment development to deliver and mix these
biocides and neutralizers.”
Green moved earlier to ban ballast water discharges in Isle Royale National
Park waters and installed a ballast treatment system onto the park’s own
passenger boat to avoid introducing a fish-killing disease to the park’s
waters. She has worked over the past three years to bring academic
researchers, industry leaders and federal regulators together to develop a
system for Great Lakes freighters.
“I can’t protect
the park unless we have a safety net for all of Lake Superior,” she said.