A Review of the Emerging Treatment Technologies for PFAS Contaminated Soils

Two researchers from Charles Sturt University in New South Wales, Australia recently published a review of emerging treatment technologies for PFAS contaminated soils in the Journal of Environmental Management (255:109896[2020]). The article provides a comprehensive evaluation of existing and emerging technologies for remediating PFAS-contaminated soils and provides guidance on which approach to use in different contexts. The functions of all remediation technologies, their suitability, limitations, and the scale applied from laboratory to the field are also presented in the article as a baseline for understanding the research need for treatment in soil environments.

Perfluoroalkyl substances (PFAS) are very stable manmade chemicals that have properties that allow them to repel both water and oil.  Chemicals in this class of more than 5,000 substances are found in products like nonstick pans (e.g. “Teflon”), waterproof jackets, and carpets to repel water, grease, and stains.  PFAS don’t easily break down, and they can persist in your body and in the environment for decades. As a result of their pervasiveness, more than 95 percent of the U.S. population has PFAS in their bodies, according to the Centers for Disease Control and Prevention (CDC).

The article states that remediation of soil contaminated with PFAS is extremely challenging.  The most widely used method to manage PFAS contaminated soil is the immobilization method.   Immobilization methods that are generally less expensive and disruptive to the natural landscape, hydrology, and ecosystems than are conventional excavation, treatment, and disposal methods. The article concludes that PFAS immobilization methods need further study to assess their long-term efficiency.

The article also examines the use of soil washing methods for the remediation of PFAS in soil.  Soil washing is an ex-situ remediation technique that removes contaminants from soil by washing the soil with a liquid (often with a chemical additive), scrubbing the soil, and then separating the clean soils from contaminated soil and washwater.  The article concludes that further work to determine the efficacy of the washing solvents.

The article also discusses other soil remediation methods that have been tested effectively in lab trials including thermal treatment techniques, chemical oxidation, ball milling, and electron beams.