Geosynthetics October/November 2021 - 21

Hybrid GCLs for
attenuation of PFAS
in landfill leachates
By Ryan Hackney and Daniel Gibbs
A
n exponential increase in understanding of the provenance, migration, and
fate of per- and polyfluoroalkyl substances (PFAS) is evident over the past
decade. The environmental and health concerns from this group of contaminants
are well recognized, but they are still evolving with advancing studies. A key
property of PFAS compounds at a molecular level is a strong carbon-fluorine
bond that makes them highly resistant to degradation, resulting in waste and
containment facilities being long-term sources of PFAS concentration due to the
day-to-day consumer items historically containing PFAS compounds that have
been, and continue to be, disposed of at these sites (Bouazza 2021).
Similar to what has been observed globally within the waste and containment
industry, an Australian national study of 27 landfills identified PFAS in
all sites of various ages and waste types, and, most significantly, in construction
and demolition waste sites (Gallen et al. 2017). Elevated PFAS concentrations
were associated with increasing pH and total organic carbon (TOC), with several
compounds showing a significant increase in concentration with decreasing
landfill age. PFAS concentrations were higher in leachates collected from currently
operating landfills than those collected from closed landfills. Australian
environmental management plans (currently PFAS National Environmental
Management Plan [NEMP] 2.0) have been, and continue to be, updated to prevent
and limit further migration, accumulation and exposure of PFAS within
the environment.
Modern landfill sites are highly engineered, with licensed facilities designed to
protect the surrounding environment from contaminants leaching out from the
waste stream. Geosynthetic liners are commonly used as liquid and gas barriers
within composite lining systems, but studies to date are limited in understanding
the interaction of PFAS compounds with the geosynthetic lining system.
Geosynthetic clay liners (GCLs) are widely used for secondary containment in
landfill applications, and detailed Australian-based research and development is
focusing efforts in determining the attenuation potential of enhanced powdered
GCLs when exposed to landfill leachates containing PFAS (Figure 1).
Ryan Hackney is the Technical
and R&D Laboratory Manager
at GRID Geofabrics Australasia
Pty Ltd. in Molendinar,
Queensland, Australia.
Daniel Gibbs is the General
Manager-Technical, Research
and Innovation, GRID Geofabrics
Australasia Pty Ltd. in Molendinar,
Queensland, Australia.
All figures courtesy of the authors.
www.GeosyntheticsMagazine.com
21

http://www.GeosyntheticsMagazine.com

Geosynthetics October/November 2021

Table of Contents for the Digital Edition of Geosynthetics October/November 2021

Geosynthetics October/November 2021 - Cover1
Geosynthetics October/November 2021 - Cover2
Geosynthetics October/November 2021 - 1
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