Destruction of PFAS During Thermal Reactivation of Granular Activated Carbon Used in Potable Water Treatment

Granular activated carbon (GAC) is one of the best available technologies for the removal of the recently regulated poly‐ and perfluoroalkyl substances (PFAS) identified by the Environmental Protection Agency. This is prompting an increasing number of municipalities to implement GAC treatment. As such, the drinking water community is seeking to better understand the fate of PFAS‐laden spent GAC. Several studies have demonstrated that thermal reactivation of GAC can accomplish destruction of PFAS; however, the work presented herein addresses the knowledge gaps for full‐scale potable reactivation facilities. Two separate reactivation trials of PFAS‐laden spent GAC were performed at a full‐scale potable‐classed reactivation facility employing two rotary kiln furnaces and an off‐gas abatement system. Three main objectives were pursued: (1) determination of the PFAS destruction removal efficiency, (2) demonstration that the current production rates and kiln operating conditions remove PFAS below detectable limits on reactivated GAC, and (3) incorporation of state‐of‐the‐art capture and analytical methods from the EPA for vapor phase PFAS and products of incomplete combustion or destruction (PICs/PIDs) analysis (OTM‐45, OTM‐50, and EPA Method 0010/8720 for fluorinated PICs/PIDs). Each of the reactivation trials consisted of three independent reactivation tests, for a total of six data sets. The 2024 Trial utilized the revised OTM‐45 method (revised in July 2024), and the 2023 Trial utilized the original OTM‐45 method. At the temperatures and operating conditions tested, no targeted PFAS were detected on the reactivated GAC and > 99.9% destruction removal efficiency of PFAS was achieved through the reactivation process. All individual compound emissions were found to exist at levels significantly below the current and proposed state regulatory values. OTM‐50 and EPA Method 0010/8270, test methods that measure reformed PFAS and PICs/PIDs, yielded non‐detect results at the sample collection points for each temperature and operating condition evaluated. The results herein demonstrate and support GAC reactivation as a viable method for the destruction of PFAS, thus breaking the cycle of these ‘forever chemicals’ within the environment.