DOE LOOKS TO TRUCK CONTAMINATED GROUNDWATER
The Department of Energy is proposing pumping up and trucking the “perched” underground contaminated water at Hanford’s 200-DV-1 Operable Unit to the new 200 West Pump and Treat Facility in central Hanford. Some of the contaminated water already has been cleaned in a successful test at Hanford’s Effluent Treatment Facility, but the cost of cleaning the water there is about $3 a gallon. Treating it at the 200 West Pump and Treat Facility, which began operating about two years ago, would cost less than 2 cents a gallon, according to a DOE engineering evaluation and cost analysis. However, the pump and treat plant is not equipped to remove the uranium contamination in the water. Under the proposal, which has agreement from Hanford regulators, the water would continue to be treated at the Effluent Treatment Facility until the new pump and treat facility’s capabilities could be expanded to include uranium. That is expected by 2015.
The water at issue, about 2 million gallons that has collected or “perched” in the soil above the water table in central Hanford, is contaminated with uranium, technetium-99 and nitrate. Technetium-99 and nitrate are among the contaminants the 200 West Pump and Treat Facility now can clean from groundwater. The water being considered for treatment moves downward through the soil until the movement slows and water builds up in a perched layer that is above the groundwater. “The perched water is believed to be slowly entering the aquifer and contributing to groundwater contamination,” according to the engineering evaluation. Contamination in the perched water comes from liquid waste disposed of in the ground during World War II and Cold War and some contamination also came from a spill in 1951 when Tank BX-102 was overfilled.
When a treatment test of the perched water was started at the Effluent Treatment Facility, the plant was the only technically sound and cost-effective way to treat it, according to the evaluation. About 150,000 gallons were treated over two years. The perched water also has to be trucked to the Effluent Treatment Facility after it is collected in wells. The facility treats up to 28 million gallons of waste water a year, including waste water collected beneath the Environmental Restoration Disposal Facility and other Hanford environmental cleanup activities. The drive to the 200 West Pump and Treat Facility is about seven miles longer, which would increase costs by about $780 per year. However, DOE still calculates that treating waste water at the newer facility would drop the cost from $6.4 million to about $1.6 million. The uranium treatment capabilities are planned to be added to the pump and treat plant for groundwater treatment whether or not the perched water is treated there. The plant is planned to treat 25 billion gallons of contaminated water pumped from the ground over its lifetime.
