Hanford workers have removed 90 tons of contaminants from Hanford groundwater over the last 10 months, keeping it from reaching the Columbia River.
Officials made the announcement as nuclear reservation workers met the Department of Energy’s goal of treating 2.2 billion gallons of groundwater in fiscal 2018 nearly two months early. The fiscal year ends in September.
The goal was met despite downtime or limited operations at water treatment systems to make improvements, said Michael Cline, a DOE federal project director for cleanup of soil and groundwater at Hanford.
The upgrades should position the six groundwater treatment plants at Hanford to continue treating contaminated groundwater at the rate of 2.2 billion gallons of water a year, he said.
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The 580-square-mile Hanford site sits over 65 square miles of contaminated groundwater. Contamination was left from World War II and Cold War production of plutonium for the nation’s nuclear weapons program.
Since groundwater treatment systems began operating in the mid-90s, about 19 billion gallons of groundwater have been treated and more than 435 tons of contaminants removed.
Currently, five systems along the Columbia River pump up groundwater contaminated with hexavalent chromium and remove the chemical before injecting clean water back into the ground. The tainted water would otherwise migrate underground to the Columbia River.
Hexavalent chromium, which can cause cancer in humans and is particularly toxic to young fish in the nearby river, was added to water used to cool plutonium production reactors to prevent corrosion.
Hanford’s largest and most sophisticated pump-and-treat facility is in the center of the site. The 200 West Pump and Treat Facility strips groundwater of more than a half-dozen contaminants, including carbon tetrachloride and radioactive constituents like uranium.
“We continually look for ways to make improvements and ensure our groundwater treatment network continues performing well,” Cline said.
One of the recent upgrades was to equipment in the plant used to remove nitrates and carbon tetrachloride.
It will help shorten the amount of time that part of the plant is down for maintenance, Cline said.
Other upgrades have included replacing plastic piping with stainless steel piping at places that see the most wear and tear in all the plants.
Some filters also were replaced with newer and more efficient filters.
“From maintenance, to operations and engineering, the teams have worked great together to continually improve performance,” said John Rendall, vice president of the soil and groundwater cleanup project for CH2M Hill Plateau Remediation Co. CH2M owned by Jacobs Engineering, is the contractor responsible for Hanford groundwater cleanup.