RICHLAND, Wash. – Another year, another 2 billion gallons of contaminated groundwater treated. It’s a repeat of last-year’s statistics, but a new chapter that illustrates continuous, consistent cleanup progress at the Hanford Site year after year.

The fiscal year that ended Sept. 30 marked eight consecutive years of topping the 2 billion-gallon mark, as the site continues to reduce risk to the Columbia River. The year’s treatment reached 2.34 billion gallons, bringing the site’s total to over 30 billion gallons treated, with nearly 700 tons of radiological and chemical contaminants removed since the groundwater treatment program began in the 1990s.

“Hanford’s groundwater program is one of the biggest success stories in our ongoing cleanup mission,” said Mike Cline, EM Richland Operations Office (RL) project director for soil and groundwater cleanup at Hanford. “But the job is not finished. We are continually seeking more efficient and cost-effective solutions to improve our systems. Protecting the Columbia River continues to drive our treatment efforts today just as it did when groundwater cleanup operations began more than 25 years ago.”

RL contractor Central Plateau Cleanup Company (CPCCo) operates five pump-and-treat systems along the Columbia River and one near the center of the Hanford Site. These systems remove radioactive and chemical contaminants from groundwater in areas where contaminated liquids were disposed in open pits near facilities that separated plutonium from fission products from the 1940s through the 1980s.

These advanced treatment facilities are just part of Hanford’s comprehensive program to target and shrink plumes — or areas of groundwater contamination — across the 580-square-mile site.

Near Hanford’s former K East Reactor, an innovative soil flushing system installed earlier this year on a half-acre area is accelerating the removal of hexavalent chromium, a hazardous chemical once used to inhibit corrosion in Hanford’s reactors. During operations, some of the chromium was spilled or leaked to the soil. Nearby groundwater treatment facilities have reduced the area of chromium contamination by more than 75% since 2010, but some contamination remains in the soil above the water table, making it difficult to remove.

The new system works by pushing up to 225 gallons per minute of clean water through the soil to force — or flush — chromium contamination in the soil to the groundwater, where it can be more easily moved through a network of existing wells to a nearby treatment facility, accelerating the cleanup process.

CPCCo’s field sampling group also plays a critical role in the success of the groundwater cleanup effort. Each year field crews log thousands of miles collecting more than 20,000 samples of soil and groundwater from hundreds of strategically placed monitoring wells. The samples are shipped to an offsite laboratory for analysis.

Detailed data gleaned from analyzing the samples helps gauge the performance of ongoing remediation efforts and supports decision-making to drive efficient, cost-effective cleanup approaches.

Work is also underway to expand capacity of the 200 West Pump and Treat Facility, Hanford’s largest groundwater treatment plant, by 50%. The expansion will increase the amount of water treated in the central part of the Hanford Site from 2,500 to 3,750 gallons a minute, potentially shortening the time required to meet cleanup goals and saving money.

“Hanford groundwater cleanup is more of a marathon than a sprint,” said Mark Cherry, CPCCo soil and groundwater program director. “While our experienced and innovative team is proud of the progress we’ve made, we’re also committed to building on that success.”