Hydraulic conductivity of compacted clay liners to landfill leachates containing PFAS

1. Home
2. Publications
3. Online Library
4. Hydraulic conductivity of compacted clay liners to landfill leachates containing PFAS

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous and persistent organic contaminants in the environment that are toxic at very low concentrations. PFAS concentrations in municipal solid waste (MSW) landfill leachates greater than 1000 ng/L have been reported, and concern has been raised regarding the effectiveness of landfill liners to contain PFAS. Moreover, no studies have been conducted to evaluate the impact of PFAS in leachate on the hydraulic conductivity of compacted clay liners (CCLs). In this study, hydraulic conductivity tests were conducted on three compacted clays used for landfill liners permeated using synthetic MSW leachate or deionized water (DIW) spiked with PFAS as the permeant solution. A low plasticity clay (CL), a high plasticity clay (CH), and a moderately plastic organic clay (OH) were used for testing. The permeant solutions contained perfluorohexanoic acid (PFHxA, a common short-chain PFAS) or perfluorooctane sulfonic acid (PFOS, a common long-chain PFAS) at a concentration of 1000 ng/L. Tests were also conducted with synthetic MSW leachate or DIW without PFAS. Hydraulic conductivity of the compacted clays to the synthetic MSW leachate was modestly higher (up to 4 times) than to DI water. Hydraulic conductivity of the compacted clays to MSW or DIW spiked with PFAS was comparable to the hydraulic conductivity to MSW leachate or DIW alone, indicating that PFAS in landfill leachates does not have significant impact on the hydraulic conductivity of CCLs.

9th International Congress on Environmental Geotechnics (ICEG2023)

Engineered Barriers