Case Study: Nitrate, Radon and PFAS Treatment Evaluation for a Water Treatment Plant

Presented on April 27, 2022, by Ilisel Espinal - GHD - at the 2022 Emerging Contaminants in the Environment Conference (ECEC22)

A private client sampled finished water from a drinking water treatment plant resulting in PFAS levels above the EPA health advisory limit of 70 ppt for PFOA and PFOS. This presentation will provide an overview of the steps taken for treatment evaluation including Basis of Design, Treatability Testing, Treatment Alternatives, and a Full-Scale Pilot Test Plan. Basis of design includes a review of existing water quality data, sampling plan and analysis of existing PFAS concentrations and organic co-contaminants. Treatability testing includes an overview of lab scale treatment models utilizing GAC and IX media to assess the removal of PFAS in drinking water. This will include lessons learned in testing media and discussion of how co-contaminants may impact media selection and disposal. Treatment alternatives discussion outlines process design options involving IX and GAC technologies and determines the most efficient media based on EBCTs, time to breakthrough, cost estimate, overall footprint, sum of PFOA and PFOS combined concentrations and compatibility and reconfiguration with the existing treatment process. The Pilot Test Plan discussion will explain how testing multiple breakthrough targets for PFOA and PFOS allows for maximized life of the resin and have secondary operational set points to adjust for PFAS regulatory changes.