This issue of Geosynthetics magazine delves deep into two innovative uses of geosynthetic clay liners (GCLs) in very different applications: coal combustion residual (CCR) leachates and per- and polyfluoroalkyl substances (PFAS) mitigation in landfills. We also examine three case studies of energy companies using high-density polyethylene (HDPE) geomembranes for flowback water in water evaporation/recycling ponds.
In the first feature, “Using Bentonite-Polymer Composite GCLs to Contain CCR Leachates” by Jiannan Chen, Sarah A. Gustitus, Yu Tan and Craig H. Benson, the authors perform tests to evaluate the hydraulic conductivity of bentonite-polymer composite (BPC) GCLs for CCR leachates from coal-fired power plants in the U.S.
In the second feature, “Hybrid Liners for Attenuation of PFAS in Landfill Leachates,” authors Ryan Hackney and Daniel Gibbs identify a need to develop a GCL that could be enhanced to further assist in the attenuation of PFAS. The authors considered options including “modification to the synthetic components of the composite, such as an additional layer of adsorptive fabric or a unique blend of staple fibers in the cover geotextile layer and additives that could be blended with the bentonite. The scope of the development included a requirement to ensure the enhanced GCL retained the mechanical and hydraulic properties of a traditional GCL, namely retention of interface and internal shear strength and maintenance of the low level of hydraulic conductivity expected from a secondary containment barrier.”
And, finally, we have, “Energy Industries Using HDPE Liners for Flowback Water Evaporation/Recycling Ponds,” in which Neil C. Nowak outlines the problem and solution to the “disposal and recycling of millions of gallons of production water (brine water) and flowback water annually generated from the oil and gas industry in an environmentally safe, less costly and efficient manner. A technology that is effective and safe is the evaporation or storage of the water in lined containment ponds after separation and removal of the hydrocarbon component from the water. Three projects are the case studies for this article, located near Wright, Wyo., Cisco, Utah, and Midland, Texas. They were designed to evaporate or recycle water in geomembrane-lined ponds.”
And don’t forget about 2021’s first in-person geosynthetics event in the U.S., GeoNashville, Nov. 4–5. Read about it in the Geosynthetics Conference Watch and GMA News columns.