In Situ Remediation Technology (InSRT) for Remediation of PFAS Contaminated Groundwater

Per- and Polyfluoroalkyl substances (PFAS) are persistent chemicals that have been introduced to the environment through manufacturing, use, and disposal of products containing PFAS. Some PFAS have been phased out of production; however, their legacy persists through widespread contamination of air, water, soil, and biota. The U.S. EPA has issued a lifetime drinking water Health Advisory Level (HAL) for the perfluoroalkyl acids (PFAAs) perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS), two of the more than 3,000 PFAS compounds, based on their potential toxicity. Many states have also developed both enforceable and non-enforceable standards and guidance values for PFAS in drinking water and groundwater. Cost-effective management technologies are sought to address the estimated market of over 2,000 PFAS sites.Conventional sorption/filtration technologies to separate PFAS from groundwater are viable for addressing PFAScontaminated groundwater; however, approaches such as sonolysis that destroy PFAS can offer a permanent solution and avoid residuals management following separation strategies. While destruction technologies for treating PFAScontaminated groundwater have been identified, their intended application is currently focused on ex situ treatment of extracted groundwater. Groundwater extraction with ex situ treatment is expensive and energy intensive.Recent developments in horizontal well drilling and application provide a means for implementing destructive technologies in situ. Horizontal wells passively capture and focus flow from a wide capture zone upgradient of a horizontal well. RemWell has developed the InSRT reactor, which when installed within a horizontal well in situ, destroys PFAS in groundwater captured by the horizontal well using sonolysis. InSRT avoid expensive and energy-intensive pumping and incineration, and ultimately reduces a site manager’s annual operating costs by 40%, while also achieving the necessary residence time for treatment and allowing for flow control.