Topic:

The Development of a Hybrid Geosynthetic Clay Liner for Attenuation of PFAS and Other Emerging Contaminants

Course Overview:

Geosynthetic Clay Liners (GCLs) have gained widespread acceptance and use in landfill lining, capping and containment applications due to their uniform quality, ease of use and low permeability to a wide variety of liquids. Their liquid barrier performance can be challenged when in contact with liquids and soils containing high concentrations of multivalent cations or extreme pH. Typical MSW landfill leachate chemistries do not often present a challenge for high quality GCL’s in terms of their liquid barrier performance but with a recent focus on Per- and Polyfluoroalkyl Substances (PFAS) in landfill leachates, it is important to consider the transport of these chemicals through GCLs. GCLs are often one of the last lines of engineered defence against the movement of PFAS into the underlying subgrade and groundwater.

This webinar session will include current information about PFAS and the types and levels in Australian landfill leachates, the development of a hybrid GCL containing a very specific activated carbon and how standard and hybrid GCLs perform their role as a liquid and contaminant barrier when in contact with landfill leachates containing PFAS.

Speaker:

Daniel Gibbs, General Manager of Technical, Research and Innovation at Geofabrics’ Centre for Geosynthetic Research, Innovation and Development (GRID) provides solutions to engineering and environmental challenges through geotechnical review, empirical research and product development.

Daniel has over 17 years of quality management, research, specification and method development, auditing, innovation, and analytical techniques in Geosynthetics with a specific focus on Bentonite and Geosynthetic Clay Liners, has authored or co-authored 11 research papers on Geosynthetic performance and is an active member of various professional bodies including ASTM Committees D35 on Geosynthetics and D18 on Soil and Rock and The Australian Chapter of the International Geosynthetics Society (ACIGS).

Learning Outcomes:

• Understand how PFAS are structured (chain lengths, head groups, common nomenclature)
• Describe the major sources of PFAS contaminants in different types of landfill leachates
• Explain the fundamental aspects of activated carbon as an adsorbent and the associated kinetics and adsorption isotherms with respect to PFAS in landfill leachate
• Learn about the development and performance of a hybrid Geosynthetic Clay Liner (hGCL) containing activated carbon permeated with landfill leachates containing PFAS
• Gain practical knowledge around MQA and CQA analysis which can be performed on the hGCL