Field Demonstration of Infrared Thermal Treatment of PFAS-contaminated Soils from Subsurface Investigations
James Hatton | CH2M Hill, Inc.
Based on the understanding of initial Department of Defense (DoD) investigations at sites with a history of aqueous film-forming foam (AFFF) usage, a large number of sites will likely require further investigation and possibly remedial action in the coming years. Investigation alone will generate substantial volumes of per- and polyfluoroalkyl substance (PFAS)-impacted investigation derived waste (IDW) from subsurface investigations. The objective of this study is to demonstrate effective field treatment of subsurface IDW contaminated with PFASs by infrared thermal desorption and off-gas capture, with ultimate destruction. The results of this study could lead to the rapid development of a mobile treatment system to treat PFAS-contaminated soil IDW.
The research team will identify a DoD installation with appropriate PFAS-contaminated soil IDW, mobilize an existing self-contained infrared thermal treatment module, and treat up to 10 tons (20 to 30 drums) of soil during a one-week pilot test period. This technology uses indirect-fired infrared heat to heat contaminated soil. This design has proven ability to treat soil/sludges with a broad range of contaminants as well as mixed contaminants (such as pesticides, polyaromatic hydrocarbons, and chlorinated solvents). Samples of soil, wipe samples from the treatment chamber, off-gas vapor, condensate, and vapor-phase granular activated carbon will be collected and analyzed to demonstrate the effectiveness of the treatment process and fate of PFASs in the treatment system.
If successful, the results from the study can be used to optimize design and operation of a self-contained mobile treatment system to efficiently and cost-effectively treat PFAS-contaminated soil IDW. This study will provide proof of concept and critical information to support routine treatment including: effective treatment temperature and duration, logistics, and permitting guidance. If successful for IDW treatment, this study could have important ramifications for full-scale remediation of PFAS-impacted soils for whole site solutions. Anticipated Project Completion - 2019)