Naval Air Station (NAS) Oceana is expanding the use of a clean-up technology for per- and polyfluoroalkyl substances (PFAS) after a successful small-scale demonstration funded by the Environmental Security Technology Certification Program (ESTCP).
By Laura Mack
ESTCP Principal Investigator Dr. David Reynolds and his project team demonstrated the D-FAS technology, sometimes referred to as in situ foam fractionation (ISFF) technology, which extracts PFAS from the environment as a foam, with the NAS Oceana team. The technology removed a significant amount of PFAS within the targeted treatment demonstration area and exhibited a potentially more efficient means of mass source removal than may be accomplished by other traditional technologies.
NAS Oceana remedial project manager Ms. Jillian Wheeler said, “[The D-FAS technology demonstration] has been really helpful for my program and its perception – that we're not just studying it, we actually are taking action.”
“[The D-FAS technology demonstration] has been really helpful for my program and its perception – that we're not just studying it, we actually are taking action.”
MS. JILLIAN WHEELER, NAS OCEANA REMEDIAL PROJECT MANAGER
Standard methods usually involve pumping groundwater. Through this process the most impacted water is not necessarily extracted in one batch, so water treatment facilities typically end up working with a diluted mixture. The D-FAS technology minimizes the amount of waste to deal with by extracting a PFAS laden concentrate through the production of foam in situ that is removed from recovery wells under vacuum.
Figure 1: The D-FAS system layout consists of a series of wells that are drilled into the shallow aquifer. Treatment wells will bubble air up through the water column, causing PFAS to distribute along the air-water interface. The PFAS-laden bubbles form as a foam at the surface. Photo Source: Geosyntec Consultants
“We get [PFAS] out of groundwater and soil by basically bubbling air into the groundwater and forcing it to adhere to the air water interface in the foam produced. Then we collect that foam, which is in a significantly higher concentration than what is in the groundwater,” explained Mr. Jason Speicher, a physical scientist at Naval Facilities Engineering Systems Command (NAVFAC) Atlantic working with the ESTCP demonstration team.
The technology consists of a series of wells that are drilled into the shallow aquifer. Treatment wells will bubble air up through the water column, causing PFAS to distribute along the air-water interface. These PFAS-laden bubbles form as a foam at the surface, leaving the groundwater with a much lower concentration of PFAS after the foam is removed. The system at NAS Oceana also consists of monitoring wells to aid in the assessment of PFAS removed from the groundwater, and recirculation wells to aid in the effective recovery and treatment of PFAS through the treatment wells.
Once the PFAS is removed, it is sent off-site for destruction. A small portion from the D-FAS demonstration was sent to Colorado School of Mines, where ESTCP is demonstrating another PFAS destruction technology, HALT, for liquid concentrates.
As shown by this demonstration, the D-FAS technology works best at high-concentration areas, like former fire training stations, with shallow ground for drilling the wells. Moving forward, the team at NAS Oceana plans to optimize and expand the system at the source zone in late 2024, collecting samples and installing more treatment wells to lower concentration levels.
In July 2023, the Department of Defense (DoD) issued a memorandum to accelerate PFAS cleanup at installations. The DoD follows federal law, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), for conducting all cleanup activities, but following each step of that process can take several years until completion. Under this memo, interim cleanup actions, including extraction systems like D-FAS, are encouraged for priority areas. ESTCP continues to support these measures by demonstrating a range of technologies – from treatment to destruction – for installations.
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About SERDP & ESTCP
The Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP) fund resilience, restoration, and conservation projects that enhance capabilities and sustain operations at Department of Defense (DoD) installations. SERDP identifies and addresses priority environmental science and technology opportunities that focus on mission requirements, and ESTCP transitions technologies out of the lab and into the field. The programs report to the Deputy Assistant Secretary of Defense for Energy Resilience & Optimization headquartered at the Pentagon. For more information, visit https://serdp-estcp.mil.
