The U.S. Department of Energy and contractor CH2M HILL Plateau Remediation Company are removing contamination from the groundwater beneath the Hanford Site to prevent contamination from reaching the Columbia River.
Contamination in Hanford’s groundwater resulted from the Site’s plutonium production for the nation’s defense dating back to the 1940s. Planned and unplanned releases of chemicals from the Site’s production facilities seeped into the soil and contaminated large areas beneath the surface.
Today, using its global expertise in the water industry, CH2M HILL Plateau Remediation Company (CH2M) is using a mixture of technologies to remove contamination from groundwater and shrink contamination plumes.
CH2M’s groundwater program includes a network of more than 2,000 wells and other tools. CH2M also collects more than 11,000 samples a year to monitor soil and groundwater contamination.
CH2M operates five pump and treat systems along the river and one at the center of the Hanford Site. Together these systems are treating well over two billion gallons (7.6 billion liters) of groundwater – enough to line up full water trucks end-to-end from Los Angeles to New York – and removing more than 100,000 pounds (45,359 kilograms) of contaminants per year. T
he systems extract contaminated groundwater from the soil via a network of wells and transfer it to a facility for treatment. The treated water is injected back into the aquifer to help drive the contaminated groundwater toward the extraction wells.
New modeling data shows the treatment technologies are effectively cleaning up groundwater and reducing the size of contamination plumes. The maps below show groundwater contamination plumes along the Columbia River in 2009 and in 2013.
Historically, an estimated 450 billion gallons (1.7 trillion liters) of liquids were discharged to the soil and migrated to groundwater deep beneath the surface.
More than 100 square miles (259 square kilometers) of groundwater were contaminated above drinking water standards. The contamination is hard to reach and difficult to control.
Continued treatment and control of the plumes is critical to stop the flow of contamination to the Columbia River, which is a resource for recreation as well as a source of drinking water for several surrounding communities.
Technology and Efficiencies
Through engineering and innovation, CH2M has expanded and enhanced Hanford groundwater treatment including:
- Installing new wells for monitoring, sampling, extracting and injecting groundwater
- Building three new pump and treat systems, including the 200 West Pump and Treat, Hanford’s largest and most sustainably-built system
- Expanding the groundwater treatment capacity from 500 million gallons (1.9 billion liters) per year to approximately two billion gallons (7.6 billion liters)
- Using a new a resin (a material used to treat groundwater) that is estimated to save $3 million annually
- Expanding a chemical barrier below the surface that will essentially lock the contaminant strontium-90 in place to decay
- Installing wells to follow plumes as they shrink or the water table changes
- Adding the ability to treat uranium contaminated groundwater in 2015
A pump and treat system operator monitors data. Hanford’s pump and treat systems can operate continuously and be controlled remotely using wireless technology.