Figure 3: Solid Scenario 2, Greenhouse Gas Emissions. From Paige Malzahn, Jacobs, Assessment of Environmental Footprints for Per- and Polyfluoroalkyl Substances (PFAS) Treatment Technologies for Liquids and Solids Battelle Remediation Conference, Denver Colorado, USA, 2nd to 6th June 2024.

Reductions in Bioavailability

It is well proven that sorbents can reduce the leachability of PFAS from soils, but how does that correlate with reductions in the bioavailability of the PFAS to sensitive environmental receptors? Professor Albert Juhasz from the University of South Australia presented new data showing that RemBind treatment reduces the bioavailability of PFAS to mice and earthworms by up to 99%. Since the conference, this work has been published in the peer reviewed literature (Caceres et al., 2024). This is consistent with previous work published on earthworms and plants Braunig et al. (2021), Juhasz et al. (2021) and Biec et al. (2023).

Co-Contaminants

PFAS is often found in soil alongside other co-contaminants including hydrocarbons and heavy metals, so any stabilisation design needs to take this into account. Sonya Carr from RemBind presented at the conference on the Immobilisation and On-Site Reuse of Soils Contaminated with Arsenic and Chromium: A Circular Economy Approach which showed that different sorbent formulations can be amended with other reagents to stabilise more than one contaminant in a single treatment step. The project used an alum sludge alongside RemBind to stabilise chromium and arsenic at an industrial site, allowing onsite reuse of the treated soil with full regulatory signoff.

Acceptance of PFAS Stabilization in the USA

Overall, the message from the 2024 Battelle Remediation Conference was that stabilisation is now accepted by industry and government alike as an important part of the PFAS soil remediation toolkit. It will likely be used alongside other technologies such as soil washing, thermal treatment and landfill, with each technology having its own ‘sweet spot’. Chatter from Industry Leaders at the conference implied that the ideal scenario for stabilisation would be for targeting relatively high volumes of diffuse PFAS contamination outside of the source zone, where other destructive technologies are simply not cost-effective. The coffee break talk had transitioned from “does stabilisation work for PFAS?” and “what about longevity?” at previous conferences, to “how can we implement stabilisation in the field?” and “what is the availability of sorbents?”.

References

• Kabiri and McLaughlin, 2021. https://doi.org/10.1016/j.scitotenv.2020.144718
• McDonough et al. 2021. https://doi.org/10.1021/acsomega.1c04789?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as
• Braunig et al., 2021. https://doi.org/10.1016/j.jhazmat.2021.125171
• Juhasz et al., 2021. https://doi.org/10.1016/j.envpol.2022.119498
• Caceres et al., 2023. https://doi.org/10.1016/j.envpol.2024.124489
• Biec et al., 2021. https://doi.org/10.1007/s11356-024-32496-7