PFASorb® is a range of modified E-Clays specifically designed to chemically immobilise the PFAS family of chemicals.
PFAS are a large, complex group of synthetic organofluorine chemicals that have been widely used since the 1940s in a variety of applications, such as cookware, clothing and in firefighting foams / flame retardant materials. The strength of the carbon-fluorine bond ensures these compounds are very stable in the environment and resistant to heat and chemical degradation.
The broad uses of PFAS in the various industries relied on their hydrophilic (dissolves in water) and lipophilic (dissolves in oils / fats) properties. Their inherent stability has resulted in an almost indefinite environmental contamination leading to long term continuous exposure of people and wildlife. Currently, there is worldwide concern of the adverse impacts arising from PFAS use on human health and the environment.
Once released into the environment, PFAS can be of considerable concern. They are highly soluble in groundwater, do not readily degrade and are highly toxic. Research into the fate and transport of PFAS in the environment and their toxicology is ongoing. Even as knowledge of these compounds increases, it is already apparent that they can be harmful to health at very low concentrations.
The remediation of PFAS compounds is an evolving field. Whilst reasonably young as a science, some technologies are developing a track record for PFAS risk management. Effective, proven treatment options for soil are limited to those that reduce leaching of PFAS to groundwater. These comprise either site capping, to reduce infiltration, or soil stabilisation using conventional binders or chemically modified clays. A range of chemical stabilisation reagents have been trialled for the latter, with modified organoclays proving to be highly effective.
Envirotreat developed and marketed E-Clay, a modified organoclay, in the 1990s to treat a range of contaminants in both soil and groundwater. The technology has been successfully used across the UK on over 150 sites since then.
Recent research and site trials has seen Envirotreat adapt the core E-Clay technology to design a robust treatment solution for PFAS compounds. Early trials on PFAS impacted sediment gave 98% reduction in leachability compared with 64 – 75% reduction using conventional stabilisation techniques, the most recent work carried out on PFAS contaminated soil gave leachate reductions of around 99%.
With this greater understanding of PFAS (and associated chemicals) and their fate in the environment, Envirotreat has now developed a range of modified organoclays specifically designed to stabilise and immobilise PFAS compounds – PFASorb. This product is now firmly part of the Envirotreat Product Family and comes with over 30 years of experience in the design and deployment of these products.
Similarly, PFAS contaminated groundwater can be treated by Envirotreat through a modified organoclay (E-Clay) Permeable Reactive Barrier (PRB). This utilises the chemical stabilisation technology to “filter” out PFAS from groundwater as it migrates through the reactive barrier, reducing the risk of contaminant migration impacting off site receptors.
A combination of PFASorb soil treatment and an E-Clay PRB presents an effective, robust and sustainable treatment solution for PFAS contaminated sites.
Envirotreat has now undertaken remediation of part of the Redditch Fire Station in readiness for a new combined Police and Fire Station emergency hub. This involved the remediation (PFASorb stabilisation) of over 4,000m3 of PFOS impacted soils. Leachate teasting indicated >95% reduction is PFOS mobility. An E-Clay Reactive Permeable Barrier was incorporated within the strategy to addrress pervasion PFOS contamination within the grounwater.
Envirotreat gave a presentation at the 2023 ESS Contamination Expo on the works undertaken, copy of the presentation in given below.