Construction on what will be Hanford's largest "pump and treat" plant to clean contaminated groundwater has reached the halfway point.
The 200 West Groundwater Treatment Facility also will be the most sophisticated at the Hanford nuclear reservation.
"The focus of this system is to keep contamination from migrating off the central plateau," said Cameron Hardy, Department of Energy spokesman.
During the Cold War, liquids contaminated with chemicals and radioactive elements were discharged from plutonium production facilities to several soil disposal sites, resulting in a 5-square-mile area of groundwater contaminated above drinking water levels in central Hanford.
Leaks from large underground waste tanks also contributed to a smaller area of contamination.
Now systems are being used along the Columbia River to pump up groundwater contaminated with chromium and then treat it before injecting clean water back into the ground. In addition, a temporary plant in central Hanford has been treating water for one contaminant, carbon tetrachloride.
But the plant being built in central Hanford will treat water for a range of contaminants: carbon tetrachloride, chromium, trichloroethene, nitrates and radioactive iodine 129, technetium 99 and tritium. The primary contaminants are carbon tetrachloride and technetium 99.
The plant will have two process buildings and five support facilities with a combined footprint of 52,000 square feet.
Equipment placement is complete for the Radiological Building and equipment installation has begun for the Biological Process Building, the largest of the main process buildings.
Construction of the plant is expected to be complete late this year, after work began to build support facilities in summer 2009. Work is being paid for with $80 million in federal economic stimulus money.
"EPA is pleased that construction has stayed on schedule," said Emerald Laija, environmental scientist for the Environmental Protection Agency, the regulator for the project. "There is a great vibe at the construction site where every worker is contributing to the project."
DOE had been planning to build the treatment plant in phases. But the entire plant is being built with the American Recovery Act money, which should allow the plant to operate at full capacity five years earlier and save an estimated $25 million in long-term treatment costs.
The system is planned to treat 25 billion gallons of groundwater at a rate of about 2,500 gallons per minute. A resin will remove radionuclides, an air stripper will remove volatile organic compounds and a bioreactor will remove nitrates.
-- Annette Cary: 582-1533; firstname.lastname@example.org; Find related stories at www.hanfordnews.com.