Soils contaminated with per- and polyfluoroalkyl substances (PFASs) at two airport fire training grounds in Australia were used in an independent validation of the commercial immobilization product RemBind™, which contains mainly activated carbon and aluminum hydroxide and clay materials. The trials were independently supervised by an external party to ensure a high level of scrutiny. Soils were mixed with 5-20% RemBind (standard grade) or RemBind Plus (high grade), fixed for 48 hours, and then analyzed for 20 PFAS compounds at a commercial laboratory using the Toxicity Characterization Leaching Procedure. Selected samples were further analyzed using U.S. EPA Method 1320 (multiple extraction procedure) as an indication of long-term binding stability. Results showed that RemBind treatment reduced the soil leachability of PFOS from 37 µg/L (site 1) and 341 µg/L (site 2) below 0.3 µg/L. For PFASs in aqueous media, PerfluorAd introduction followed by RemBind polishing provides an innovative treatment process. In pretreatment, liquid PerfluorAd active compound is metered into a stirring tank to precipitate PFASs. Precipitation products are separated from the water as micro-flocs by processes such as sedimentation and filtration. The precipitants can be concentrated to a very high degree, which allows for economical disposal. A downstream RemBind filter treats the residual contaminants. Owing to the significant reduction in the PFAS contaminant load in the PerfluorAd stage (up to 90%) the absorbent filter lifetime is extended significantly.
Presentation slides: http://www.contaminantssummit.com/images/presentations/1_GaryBirk.pdf
PerfluorAd poster: http://www.umsicht.fraunhofer.de/content/dam/umsicht/de/dokumente/pressemitteilungen/2012/120110-poster-pft-en.pdf