Evaluation of a drop-in waste volume reduction method for liquid investigation derived waste containing per- and polyfluoroalkyl substances

Abstract

Development of on-site treatment strategies for PFAS-containing investigation derived waste (IDW) will decrease the potential for secondary release following off-site disposal, lower disposal costs, and promote more effective long-term management of PFAS-laden waste. Herein, we report the application of a simple, drop-in treatment that utilizes one of two PFAS sorbents: bituminous granular activated carbon (GAC) or strong base anion exchange resin (IX) and a small circulation pump to adsorb and concentrate PFAS impacted mass from liquid IDW collected from two sites with disparate water chemistries and synthetic IDW amended with PFAS-containing aqueous film forming foam (AFFF). Bench scale intermittent circulation experiments revealed that bituminous granular activated carbon (GAC, 0.5 mg/mL) removed up to 97.0 ± 1.4% and 96.4 ± 0.5% of PFOS and PFOA, respectively, in both site-derived IDW sources. Improved performance was observed in experimental treatments containing a strong base anion exchange resin (IX, 0.5 mg/mL), where up to 99.4 ± 0.1% and 96.7 ± 0.2% of PFOS and PFOA were removed, respectively. High chloride concentrations (20 g/L) reduced removal of short chain perfluorocarboxylates (PFBA and PFHxA) using GAC or IX, but high salt concentrations had negligible effects on the removal of PFOA, PFBS, PFHxS, or PFOS. Excellent scalability was observed in mesoscale experiments, where the majority of amended PFAS mass was removed from synthetic IDW within five days of vessel circulation using two different PFAS-capture configurations. Combined PFOS and PFOA concentrations were reduced to levels below 0.07 μg/L using either GAC or IX for both configurations. Results generated in this study support the application of this approach as an economical strategy for potential waste volume reduction in IDW destined for off-site disposal.