Gas permeability of partially hydrated geosynthetic clay liner under two stress conditions

Abstract

The results of a series of gas permeability tests, with monitoring of gravimetric/volumetric moisture content and total suction, on a commercially available needle-punched geosynthetic clay liner (GCL) are presented. GCL specimens were partially hydrated with deionised water under 2 and 20 kPa confinement prior to testing. The tests were conducted at differential pressures ranging from 1 to 10 kPa. Gas permeability was found to decrease with an increase in gravimetric/volumetric moisture content and a decrease of suction. The effect of the preconditioning stress was found to be more pronounced at gravimetric moisture contents greater than 40% (25% apparent degree of saturation, 0·30 m3/m3 volumetric moisture content), and suctions less than 1·6 MPa

Interactions of Per- and Polyfluoralkyl Substances (PFAS) with Landfill Liners

“…The sodium bentonite component of the GCL must perform over a wide range of field conditions, but the hydration of sodium bentonite used in GCL in Australia has been the focus of intense local [72, 88, 89, 92-94, 96-101, 112-120] and international [65,87,90,104,106,108,109,[121][122][123][124][125] research. It is well established that pre-hydration and maintenance of a high hydration state of the sodium bentonite are necessary for optimal attenuation of both liquid and gaseous diffusion [72,112,126] and therefore the presence of an effective barrier against PFAS compounds (Figure 4). A variety of polymer-enhanced sodium bentonites are currently available on the worldwide market, including in Australia [127][128][129][130].…”

“…Gas permeability of a granular GCL as a function of hydration under two nominal applied stresses associated with cover and side-slope liner systems [112].…”

“…Lower gas permeability is generally observed for a given water content (above a threshold value ≈ 0.3 vol.% or ≈ 100% gravimetric water content, GWC) with increasing confinement. However, even high water content cannot provide acceptably low gas permeability if the GCL is under very low confining stress [112]. The amount of hydration is also dependent on the form of the bentonite in the GCL, with granular bentonite usually requiring a higher water content (and more time to equilibrate at that water content) than powder bentonite [112,126,131].…”

Novel Techniques to Simulate and Monitor Contaminant–Geomaterial Interactions

“…Some good examples of gas-geomaterial interaction are: remediation of contaminated soils by air sparging [145], carbon sequestration [154], radioactive waste disposal [104] and gas permeation in porous media [151]. Incidentally, determination of specific surface area, SSA, of geomaterials, by employing: (a) Blaine's air permeability apparatus [6] and (b) absorption/adsorption techniques, wherein methylene blue, nitrogen gas, ethylene glycol monoethyl ether, EGME and air, are employed [5], is another good examples of gas-geomaterial interaction.…”

Sorption and diffusion of bisphenol-A (BPA) through a geosynthetic clay liner (GCL)

“…There have been many recent studies related to the performance of GCLs (e.g. Acikel et al, 2015;Ashe et al, 2015;Bannour and Touze-Foltz, 2015;Brachman et al, 2015;Di Emidio et al, 2015;Fox and Stark, 2015;Hanson et al, 2015;Liu et al, 2015;Mazzieri and Di Emidio, 2015;Puma et al, 2015;Rouf et al, 2016Rouf et al, , 2015bTake et al, 2015a,b in 2015 alone) but relatively few previous studies have examined the diffusion through GCLs. The latter include consideration of diffusion of sodium and chloride , some volatile organic compounds (Lake and Rowe, 2004;Rowe et al, 2005), metals , and some phenolic compounds (Mendes et al, 2013) through GCLs.…”