The Department of Energy is expecting to save up to$1.6 million a year at Hanford after switching to a new resin to strip chromium from contaminated ground water.
"It removes more chromium at much less cost," said John Morse, Department of Energy senior technical adviser.
The resin first was used at a new water treatment plant that began removing chromium from ground water near the former D and DR reactors in late 2010.
It proved so successful that it now is being used at all five Hanford ground water treatment plants targeting chromium contamination.
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At the plants near the Columbia River, ground water is pumped up and run through tanks to be treated with resin that strips out the chromium. Then the cleaned water is injected back into the ground.
Sodium dichromate used to be added as a corrosion inhibitor to river water used to cool reactors that produced weapons plutonium at Hanford during World War II and the Cold War. It leaked from transfer systems and piping over decades to contaminate soil near many of the reactors.
The previous resin could absorb no more chromium after about a month of use, requiring about 100 change-outs total among the tanks in a pump and treat plant in a year.
The resin then would be trucked to Minneapolis to be cleaned of chromium and sent back to Hanford for reuse.
But the new resin, manufactured by ResinTech, has not required a change-out since the new plant near the D and DR reactors began operating about 18 months ago, said Bob Popielarczyk, vice president of soils and ground water remediation for CH2M Hill Plateau Remediation Co. It holds about 15 times as much chromium as the previous resin.
Less transportation and less worker handling not only save money, but less transportation also has an environmental advantage, Popielarczyk said.
The new resin can be disposed of at Hanford, eliminating transportation costs.
Chromium is of particular concern because it is toxic to young fish at very low levels, including levels that meet drinking water standards. The DOE goal is to get contamination entering the river down to 10 parts per billion or less to protect aquatic life.
While the old resin could remove contamination to leave treated water with just 5 parts per billion of chromium, the new resin removes chromium to levels that no longer can be detected, Morse said.
DOE began looking for a better way to remove chromium from ground water several years ago, in part because of small amounts of radioactive contamination in the resin which needed to be recharged.
DOE and CH2M Hill came up with eight resins to test, and all but the ResinTech product filled up with chromium during testing, Popielarczyk said.
The new resin originally was used at the 100-DX Ground Water Treatment Facility near the D and DR reactors, and then in a second new treatment facility built to treat the chromium contaminating ground water near the former H Reactor. That pump-and-treat station began operating last fall.
DOE and CH2M Hill since have converted the three pump-and-treat systems near the former K East and K West reactors to use the new resin.
The five systems combined are expected to cost $1.2 million to $1.6 million less per year to operate with the new resin, including reduced resin transportation costs.
"By saving money, we can use it to go after other cleanup work," Popielarczyk said.
-- Annette Cary: 582-1533; firstname.lastname@example.org