Theme: 07. Per- and Polyfluorinated Alkyl Substances (PFAS)

Topic Area: 7q. Managing PFAS at Publicly-Owned Treatment Works (POTWs)

Formatted Title:

POTW Acceptable Treatment of PFAS with Surface Active Foam Fractionation

Background/Objectives:

Publicly owned treatment works (POTW) are designed to treat domestic sewage, municipal wastewater, and other liquid wastes. When a new constituent becomes deemed hazardous this puts stress on the POTW and its treatment capacity. Per- and polyfluoroalkyl substances (PFAS) present additional stress on POTW systems due to their low sorption coefficient, recalcitrant nature, and low treatment guidance.

Approach/Activities:

Surface active foam fractionation or SAFF® has been pioneered by Australian-based EPOC Enviro, and commercialized in the United States by Allonnia. SAFF® comprises a treatment train of stages that aerate PFAS-contaminated water collecting the PFAS at the surface interface. This ability to remove PFAS is due PFAS’s amphiphilic nature which is attracted to water on one end and air on the other. Most of the water moving through the SAFF® system is expelled after the first state of fractionation with PFAS compounds removed. The low-volume PFAS foamate is further concentrated before collection and disposal or destruction.

Results/Lessons Learned:

Various emerging methods have been used to destroy PFAS by breaking the carbon and fluorine bonds, such as supercritical water oxidation, and electrochemical oxidation. Along with the SAFF® effluent, these modern destruction technologies result in benign residues able to be discharged directly into the POTW without additional stress to the system. SAFF® is a technology being rapidly adopted to remove PFAS and meet guidelines for discharge to POTW systems.

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Robert Rappold