PROJECT TITLE: Permeation of Fluorotelomer Alcohols through Two-Layer Landfill Liners

Project Sponsor: Hinkley Center for Solid and Hazardous Waste Management

Project Duration: Oct. 01, 2025 - Sept. 30, 2026

Project Overview

The objective of this project is to determine the permeability of representative volatile per- and polyfluoroalkyl substances (PFAS) (i.e., fluorotelomer alcohols (FTOHs)) through a typical landfill liner system that consists of two low-permeability layers, including a geomembrane layer made of high-density polyethylene (HDPE) and a geosynthetic clay liner (GCL) made of sodium bentonite. The outcomes will be summarized through answers to frequently asked questions, e.g., Which layer is more permeable to FTOHs? What is the breakthrough time and permeation coefficient for each layer? FTOHs are among the most abundant volatile PFAS in landfill gas and leachate. HDPE is the most widely used geomembrane in landfill liners. GCL is commonly used to replace the conventional clay liner due to its much smaller thickness that makes its transportation and installation easier.

Task 1 (i.e., Experiments with a two-layer barrier) will experimentally study the permeation of four FTOHs (i.e., 4:2, 6:2, 8:2, 10:2 FTOHs) through a barrier that consists of a geomembrane layer (HDPE) and a GCL layer (bentonite) at four temperatures (i.e., 40, 50, 60, and 70 °C). Breakthrough times will be obtained in this task. Other data will be used in Task 2.
Task 2 (i.e., Determination of permeation parameters) will mathematically determine three permeation parameters (i.e., permeation, diffusion and partition coefficients) by fitting the experimental data from Task 1 with mathematical models. The permeation parameters at temperatures that are not tested in Task 1 will be predicted through the Arrhenius relationship.
Task 3 (i.e., Evaluation of permeation parameters and recommendations): The HDPE-related parameters will be independently determined in the current project and a previous project. They will be cross-checked. Recommendations will be made in the context of PFAS regulations.