It has been almost one month since we were in Orlando for the Water Quality Assn. Convention & Exposition, and we keep thinking back to our...
Along the Columbia River sits the Hanford Site, a facility used to produce plutonium for atomic bombs during the Cold War. To cool the facility's nine nuclear reactors, sodium dichromate — a chemical used as a corrosion inhibitor — was added to river water. Due to leaks in the sodium dichromate transfer systems and piping, and because cooling water treated with sodium dichromate was periodically discharged into the soil near the reactors, the soil and groundwater became contaminated with hexavalent chromium (chromium-6).
To protect the local environment, the U.S. Department of Energy (DOE) needed to reduce the chromium-6 levels in the groundwater entering the Columbia River. It tried various methods, including precipitating the contaminant "in situ," but eventually resorted to offsite treatment. The first pump and treatment system were installed in 1996.
While previous technology reduced the chromium-6 levels to 5 ppb, the search continued for better equipment.
The DOE and contractor CH2M HILL first looked at using ResinTech Inc.'s media in 1998, but the company felt it was too expensive. Offsite regeneration of the strong base anion resin, however, became increasingly problematic; and although an onsite regeneration system was built, issues associated with wastewater treatment and disposal made it prohibitively expensive.
In 2008, the DOE began seriously considering ResinTech’s SIR-700 product. Based on the success of extensive pilot testing, the product was adopted for full-scale implementation in 2009, and older systems were retrofitted in 2011.
The system has been successful in removing chromate from the soil and groundwater, reducing chromium-6 at the Hanford site to non-detectable levels, and slowing the rate at which chromate is moving toward the Columbia River.
In August 2012, Tracy Mustin, principal deputy assistant secretary for environmental management for the DOE; Jane Hedges, program manager for the Washington State Department of Ecology; and Dan Opalski, director of the U.S. Environmental Protection Agency (EPA) Region 10 Office of Environmental Cleanup, attended a celebration recognizing the beginning of operations at the plant.