As the nation and world continue to learn more about the hazards of the latest emerging chemicals and how to deal with them, at Fort Leavenworth the installation implemented a water treatment project heralded as a possible model for how to keep drinking water safe.
In 2017, samples from the raw and finished drinking water from the garrison’s five production groundwater wells showed that three of the five wells were above the Environmental Protection Agencies health advisory levels for per- and polyfluoroalkyl substances known as PFAS. The most studied PFAS are perfluoro octane sulfonate or PFOS, and perfluorooctanoic acid or PFOA. To ensure availability of safe drinking water, garrison leadership made plans to purchase drinking water from the city of Leavenworth, whose water tested clear of PFOS/PFOA, through a pipeline at an annual cost of $1 million, while a team was formed to develop a long-term solution.
In 2018, the U.S. Army Environmental Command began assessing Army installations for PFAS releases and Fort Leavenworth was one of the first PFAS-impacted installations to begin the comprehensive analysis. USAEC contracted with a private firm through the U.S. Army Corps of Engineers, Kansas City.
As the project continued, Fort Leavenworth and USAEC working with agencies such as the Kansas Department of Health and Environment, gained approval to construct a four-vessel granular activated carbon filtration system adjacent to the existing drinking water treatment plant. Adding a step to an historic structure, the existing water treatment plant is inside a National Historic Landmark District, so the team successfully applied to, and was approved, by the Kansas State Historic Preservation Office, to add the new structure.
In recent testing, the project has posted impressive results. Fort Leavenworth has ultimately been able to meet the 2016 PFOS/PFOA target of 70 ppt combined concentration in drinking water. The implementation of the GAC filters also exceeded the requirement by producing drinking water which has no detections for not only the two most common PFAS, but an additional 22 PFAS compounds.
As part of testing for future technology, Fort Leavenworth provided contaminated raw water for an initial bench-scale and hosted a two-week field demonstration of a new technology to destroy PFAS in groundwater. That testing resulted in 98% destruction of PFOA and 86% destruction of PFOS with similarly high destruction of many resultant shorter chain PFAS, but on a small scale (low throughput). Improvements to the technology based on results of testing at several military installation continues.
Even as the U.S. Environmental Protection Agency proposed regulations continue to consider increasingly stringent standards for PFAS, the GAC filter system at Fort Leavenworth continues to post good results. During the first four months of operation the GAC filters had been non-detect for all 24 PFAS compounds currently analyzed.
“We’re excited to see the system producing these results, and even more excited to be able to use this new filtration system on 100% of the water used by the soldiers, families and employees of Fort Leavenworth,” said Col. John Misenheimer, Fort Leavenworth garrison commander. “This collaborative project not only keeps our people safe from these chemicals, but it has already saved the Army from having to immediately retrofit the treatment plant to meet the latest more stringent health advisory levels.”
Misenheimer added that this work will be ongoing: “Because PFAS contamination and health impacts are receiving greater attention at the national and state level, the remediation landscape for these compounds will continue to change over the next decade or longer. As a result of the Army’s proactive stance by adopting the 2016 health advisory levels as target levels, Fort Leavenworth has been able to get ahead of the regulatory community and provide drinking water that exceeds all pending and foreseeable standards for PFAS removal using a tried-and-true technology at an industrial scale.”
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