Per- and polyfluoroalkyl substances (PFASs) are a class of emerging contaminants that have impacted drinking water sources for many communities. Although not regulated, drinking water utilities are periodically required to test for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Various engineering technologies have been studied for the remediation of PFASs, including granular activated carbon, ion-exchange resin, reverse osmosis, nanofiltration, and oxidation/reduction processes; however, each of these treatment trains suffers from specific drawbacks. In this presentation, we describe a treatment train combining nanofiltration (NF) with UV photochemical reduction for the removal and destruction of PFASs from contaminated groundwater from a military base. Through NF concentration, rejection of perfluoroalkyl acids (e.g., PFOA and PFOS) ranged from 92% to 99%, where shorter chains (3 to 4 carbons) were generally rejected less than longer chains (5 to 8 carbons). PFASs in the concentrated NF reject stream were reductively degraded by reaction with hydrated electrons (e<sub>aq</sub><sup>–</sup>) formed by UV photolysis of chemical sensitizers, with half-lives ranging from 3 to 30 hr depending on PFAS chain length and polar head group. This presentation will discuss our efforts toward a pilot-scale system employing this treatment train, and contrast this technology with others currently being evaluated for PFAS removal and degradation.

Combination of nanofiltration and UV-sulfite as a novel treatment train for the removal and destruction of PFASs in AFFF-impacted groundwater

2019 Spring National Meeting

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