August 11, 2012 in City

Hanford water treatment plant opens

Annette Cary Tri-City Herald
 

Hanford’s largest and most sophisticated groundwater treatment plant has begun work to remove an estimated 110,000 pounds of pollutants over the next 25 years.

Its treatment capacity each month is 108 million gallons, or the equivalent of 108 typical city water towers.

Like five other groundwater treatment plants operating at Hanford, it will clean water pumped out of the ground, and then the cleaned water will be reinjected into the Earth.

But the 200 West Groundwater Treatment Facility is designed with multiple technologies to remove not just one contaminant, but up to eight radioactive and chemical pollutants from groundwater.

“This facility is key to Hanford’s groundwater strategy and in ensuring that the Columbia River is protected,” said Matt McCormick, manager of the Hanford Department of Energy Richland Operations Office. He spoke to about 200 workers and officials gathered Thursday to celebrate the opening.

The plant is attacking one of Hanford’s largest groundwater plumes, which stretches over the northern portion of the 200 West Area.

When Hanford was producing plutonium for the nation’s nuclear weapons program during World War II and the Cold War, more than 450 billion gallons of contaminated liquid was discharged into the soil in central Hanford. That’s almost equivalent to Lake Coeur d’Alene, McCormick said.

Initially, CH2M Hill Plateau Remediation Co. will use the plant to remove three key contaminants from groundwater.

The plume includes technetium 99 from the Hanford tank farms, where radioactive waste is stored in underground tanks. It has nitrates from the nitric acid used to chemically separate plutonium from irradiated fuel. And it has carbon tetrachloride, which was used at the Plutonium Finishing Plant.

Groundwater that’s contaminated with radionuclides will be sent to the plant’s 17,500-square-foot radiological process building to have technetium 99 removed with resins in an ion exchange system. It starts operations next week.

As work expands at the plant to treat water contaminated from the southern portion of the 200 West Area, uranium also will be removed with a different resin.

After removal of radionuclides, the water will be sent to the 35,000-square-foot main process building to have the hazardous chemicals that remain removed. It already is operating, treating water contaminated only with hazardous chemicals.

It uses microorganisms to consume nitrates. An air stripping system removes carbon tetrachloride.

The cleaned water is reinjected into the ground around the contaminated plume to help keep it from flowing underground toward the Columbia River.

Much of the waste from the contaminated water can be disposed at the Environmental Restoration Disposal Facility, a lined landfill in central Hanford.

The resins used to remove radionuclides will be sent there and also the biosludge after it is thickened, dried and then combined with lime to shut down the biological process and create waste that’s as hard as concrete.

The activated carbon from the air-stripping system will be sent out of state to be cleaned and returned.

“I’m in awe of the size and scope,” said Tracy Mustin, DOE’s principal deputy assistant secretary for environmental management, after touring the building.


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