Permeation of two GCLs with an acidic metal-rich synthetic leachate

Mazzieri, Francesco; Emidio, Gemmina Di; Fratalocchi, Evelina; Sante, Marta Di; Pasqualini, Erio

doi:10.1016/j.geotexmem.2013.07.011

Cited by 55 publications

(10 citation statements)

References 41 publications

(50 reference statements)

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“…i.e., Dk >> 0 (e.g., Shackelford et al, 2000;Jo et al, 2001Jo et al, , 2005Kolstad et al, 2004;Lee and Shackelford, 2005a, b;Lee et al, 2005;Shackelford et al, 2010;Ishimori and Katsumi, 2012;Rosin-Paumier and Touze-Foltz, 2012;Liu et al, 203, 2014Liu et al, 203, , 2015Mazzieri et al, 2013;Bouazza and Gates, 2014;Makusa et al, 2014). In cases where significant increases in k are deemed likely, consideration has been given to the potential use of chemically modified bentonites in GCLs for the primary purpose of mitigating any such incompatibility in order to maintain a low k (e.g., Onikata et al, 1999;Katsumi et al, 2008;Di Emidio, 2010;Mazzieri et al, 2010;Scalia et al, 2011Scalia et al, , 2014Bohnhoff, 2012;Scalia, 2012;Bohnhoff and Shackelford, 2014;Di Emidio et al, 2015;Mazzieri and Di Emidio, 2015).…”

Section: Introductionmentioning

confidence: 99%

Limiting membrane and diffusion behavior of a geosynthetic clay liner

Shackelford

Meier

Sample-Lord

2016

Geotextiles and Geomembranes

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a b s t r a c tBentonite based geosynthetic clay liners (GCLs) are commonly used as chemical containment barriers to minimize liquid flow and contaminant transport. The preference for GCLs relative to other materials for chemical containment include economy of use and superior engineering properties, including low hydraulic conductivity (k) and the ability to exhibit semipermeable membrane behavior that restricts the migration of solutes through the bentonite. In the case of low k (e.g., 10 À10 m/s), diffusion is likely to be a significant, if not dominant, mechanism of chemical transport. The objective of this study was to evaluate the membrane and diffusion behavior of a GCL in the limit as the salt (KCl) concentration increased to the extent that any observed membrane behavior was destroyed. The results indicated that the observed membrane behavior for the GCL was essentially destroyed when the average KCl concentration across the GCL specimen, C ave , reached 200 mM KCl, which was greater than the value of C ave that would have been predicted on the basis of previous results. The results also indicated that the value of the effective diffusion coefficient, D * , for Cl À at this limiting value for C ave of 200 mM KCl was greater than the value of D * that would have been predicted on the basis of the use of lower values of C ave . However, the differences between the measured and predicted values of D * were relatively minor ( 11.3%), such that the differences likely would be insignificant for most practical applications.

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Section: Introductionmentioning

confidence: 99%

Limiting membrane and diffusion behavior of a geosynthetic clay liner

Shackelford

Meier

Sample-Lord

2016

Geotextiles and Geomembranes

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“…Katsumi et al (2008) conducted permeability tests for up to 5 years using flexible-wall permeameters (ó9 i ¼ 25 kPa) to investigate the performance of a DPH-GCL and found k , 5.0 3 10 À12 m/s for electrolyte solutions with concentrations of up to 1 mol/l CaCl 2 . Mazzieri et al (2013) permeated a DPH-GCL in two stages: the first was carried out with distilled water (DW), the second was carried out with a synthetic solution having pH ¼ 2.0 and containing Cu 2+ , Zn 2+ and Pb 2+ , each at concentrations equal to 25 mmol/l. The k to DW was 3.7 3 10 À12 m/s and increased to 1.3 3 10 À11 m/s upon permeation with the synthetic solution.…”

Section: Dense Prehydrated Gclsmentioning

confidence: 99%

Hydraulic conductivity of a dense prehydrated geosynthetic clay liner

Mazzieri

Emidio

2015

Geosynthetics International

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Dense prehydrated geosynthetic clay liners (DPH-GCLs) are a particular type of GCL which, unlike conventional GCLs manufactured with dry bentonite, contain bentonite prehydrated during manufacturing. DPH-GCLs are produced by a patented process that includes bentonite prehydration with a polymer solution and vacuum extrusion. This paper describes the results of permeability tests that were carried out using flexible-wall permeameters to investigate the hydraulic conductivity of a DPH GCL to water, natural seawater and a 12.5 mmol/l CaCl 2 solution. Moreover, the efficiency of the 0.1 m overlap seams between DPH-GCL panels has been investigated by means of a medium-scale permeameter able to accommodate specimens 0.305 m in diameter. Test results showed that the DPH GCL has very low hydraulic conductivity to water (10 À12 -10 À11 m/s) and preserve low permeability, of the order of 10 À11 m/s, in the presence of relatively high calcium concentration in the permeating liquid. However, the efficiency of overlap seams can be affected by the permeant type. In the presence of permeant liquids that inhibit swelling (e.g. seawater), the hydraulic efficiency of the seams needs to be improved by adding bentonite paste at the overlap interface. The hydraulic performance of the DPH-GCL is attributed to the combination of prehydration, densification and chemical amendment.

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“…Prehydration has been suggested as a means to prevent the hydraulic conductivity of bentonite barriers from being altered by leachate permeation. Prehydration is hydration of the bentonite with a dilute solution (e.g., deionized, distilled, or tap water) by soaking or permeation prior to permeation by a chemical solution (Liu et al, 2015;Scalia et al, 2014;Shackelford et al, 2014;2000;Mazzieri et al, 2013;Zhu et al, 2013;Brown and Shackelford, 2007;Katsumi et al, 2007;Jo et al, 2004;2001;Kolstad et al, 2004;Egloffstein, 2001;Vasko et al, 2001;Petrov and Rowe, 1997;Ruhl and Daniel, 1997).…”

Section: Case 2: Cracking Effect Of the Bentonite-based Barriersmentioning

confidence: 99%

“…Thus, factors that affect the fraction of bound water directly affect the hydraulic conductivity of bentonite (Wijeyesekera et al, 2012;Shackelford et al, 2000;Mesri and Olsen, 1971;McNeal et al, 1966). Various studies have shown that the hydraulic conductivity of GCLs can be affected between a factor of 10 and 10,000 when permeated with inorganic permeant solutions (Liu et al, 2015;Scalia et al, 2014;Shackelford et al, 2014;2000;Hosney and Rowe, 2013;Mazzieri et al, 2013;Zhu et al, 2013;Benson et al, 2010;Brown and Shackelford, 2007;Katsumi et al, 2007;Jo et al, 2004;2001;Lee and Shackelford, 2005;Guyonnet et al, 2005;Kolstad et al, 2004;Egloffstein, 2001;Jo et al, 2001;Petrov and Rowe, 1997).…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Flow through Engineering Bentonite-Based Containment Barriers

Loh¹,

Wijeyesekera²

2015

American Journal of Applied Sciences

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This paper presents the use of software modelling as a tool to study the impact of hydraulic "resistivity" on the contaminant transport through bentonite-based containment barriers. A sensitivity analysis on the predicted data was carried out by varying the boundary conditions as well as the hydraulic resistance to flow through varying contaminant transport parameters. Accordingly, both advective and diffusive flow processes are considered as that which resists the flow. In particular, the effect on the contaminant migration due to desiccation cracking is explored. Laboratory evidence is provided and discussed to show how the initial microstructure of the clay influences the development of subsequent macro structural features such as shrinkage crack patterns. The effect of these cracks and the intensity of cracking on the contaminant migration are modelled and pragmatically discussed. Additionally, the effect on the hydraulic conductivity of bentonite-based barriers, when permeated with non-standard liquids is discussed and a typical analytical output is presented.

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Permeation of two GCLs with an acidic metal-rich synthetic leachate

Cited by 55 publications

References 41 publications

Limiting membrane and diffusion behavior of a geosynthetic clay liner

Limiting membrane and diffusion behavior of a geosynthetic clay liner

Hydraulic conductivity of a dense prehydrated geosynthetic clay liner

Hydraulic Flow through Engineering Bentonite-Based Containment Barriers

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