Perfluoroalkyl Substances – What You Need to Know
- Allison Reinert PE, Ben Stanford PhD, Eileen Feldman PE - Hazen and Sawyer
In May 2016, the EPA issued new guidelines for perfluoroalkyl substances also known as perfluorinated compounds (PFCs) in drinking water. These PFCs included in the guidelines are perfluorooctanoic acid or PFOA (also known as C8, PFOA is a processing aid in the manufacture of TeflonTM) and perfluorooctane sulfonate or PFOS (commonly found in fabric protectants). These are contaminants of concern at low levels for pregnant or breastfeeding women because they bioaccumulate and can be passed on to the fetus. While there is no federal drinking water MCL for PFOA and PFOS, the new EPA guideline is 0.07 mg/L for PFOA, 0.07 mg/L for PFOS, and 0.07 mg/L for PFOA and PFOS combined. The EPA had previously instituted a Provisional Health Advisory level of 0.4 mg/L for PFOA and 0.2 mg/L for PFOS for short-term exposure in humans. Although the removal of PFCs from source waters depends on concentration, raw water quality and other variables, several treatment processes have proven to remove up to 90% or greater of PFCs in finished water. Granular activated carbon (GAC) and high pressure membrane filtration can remove over 90% of PFCs from source water. Some powdered activated carbons (PAC) have also been shown to remove PFCs though the efficacy is typically limited by contact time and dose. Anion exchange has also een successful at removing between 10% to over 90% of PFCs from drinking water, depending on the specific compound, the type of ion exchange resin, and other water quality parameters. This paper will review PFCs and their sources along with discussing current work with using GAC and PAC for PFC removal along with the impacts to water treatment facilities and options for utilities to prepare for future regulatory requirements and drinking water goals related to perfluoroalkyl substances such as:
- Guidance on monitoring plans
- Guidance on sampling
- Public outreach and reporting
- Bench-scale testing
- Pilot-scale GAC studies are suggested for evaluation at site specific locations
As part of this presentation, both full-scale case studies and pilot and bench-scale studies from across the country will be illustrated along with recommendations for various water systems with different water qualities and ultimate treatment goals.
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