Effect of ammonium on the hydraulic conductivity of geosynthetic clay liners

Setz, Melissa C.; Tian, Kuo; Benson, Craig H.; Bradshaw, Sabrina L.

doi:10.1016/j.geotexmem.2017.08.008

Cited by 50 publications

(15 citation statements)

References 18 publications

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“…Conventional GCLs consist of a thin (approximately 7-10 mm) layer of powdered or granular sodium bentonite (NaB) sandwiched between two geotextiles (GTs) joined by needlepunching or stitching. The low hydraulic conductivity of NaB GCLs is attributed to osmotic swelling of montmorillonite, the primary mineral in bentonite (Norrish and Quirk 1954;Kolstad et al 2004a;Scalia et al 2014;Tian et al 2016;Setz et al 2017). Water molecules associated with osmotic swelling are strongly bound to the mineral surface and are effectively immobile, reducing the size, number, and connectivity of hydraulically active pores (Kolstad et al 2004a;Scalia et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Polymer Elution and Hydraulic Conductivity of Bentonite–Polymer Composite Geosynthetic Clay Liners

Tian

Likos

Benson

2019

J. Geotech. Geoenviron. Eng.

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Hydraulic conductivity tests were conducted on two commercially available bentonite-polymer composite (BPC) geosynthetic clay liners (GCLs) containing the same dry blend of sodium bentonite (NaB) and polymer sandwiched between two nonwoven geotextiles (GTs) bound by needlepunching: a bentonite-polymer GCL (BP GCL) and bentonite-polymer GCL with silt film (BPS GCL). The GCLs were essentially identical except that the BPS GCL contained a woven slit-film GT to constrain polymer elution. The slit-film GT was located inside the GCL adjacent to the downstream nonwoven GT. The test liquids were deionized (DI) water and 20-500 mM CaCl 2 representing dilute to high-concentration permeant solutions. Effluent from the hydraulic conductivity tests was analyzed for total organic carbon (TOC) to quantify polymer elution. Scanning electron microscopy (SEM) was used to capture how the solution chemistry affected the fabric of the BPC and how hydraulic conductivity was related to pore-scale features in the fabric. Both BPC GCLs were approximately one to four orders of magnitude less permeable than a conventional NaB GCL permeated with the same solutions. Polymer elution data and SEM images of polymer structure suggest that polymer retention in the pore space and pore clogging by polymer hydrogel are responsible for the lower hydraulic conductivity of BPC GCLs. The BPS GCL had less polymer elution and hydraulic conductivity three orders of magnitude lower than the BP GCLs when permeated with 50 and 100 mM CaCl 2 solutions because the slit-film GT reduced polymer elution from the bentonite. A conceptual framework is proposed relating solution chemistry, pore-scale fabric, and hydraulic conductivity of dry-blended BPC GCLs.

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Section: Introductionmentioning

confidence: 99%

Polymer Elution and Hydraulic Conductivity of Bentonite–Polymer Composite Geosynthetic Clay Liners

Tian

Likos

Benson

2019

J. Geotech. Geoenviron. Eng.

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“…19,20 The main component of sodium-based bentonite is sodium-based montmorillonite, 21 which produces osmotic expansion through strong water absorption of sodium ions, reduces seepage pores and increases curvature. 22,23 However, extreme pH conditions, cation exchange, and high ionic strength solutions could cause sodium-based montmorillonite to lose its permeability. 24,25 In order to improve the chemical permeability of conventional sodium bentonite GCLs, bentonite-polymer composite GCLs (BPC GCLs) have been developed in recent years.…”

Section: àmentioning

confidence: 99%

Attenuation of Cr/Pb in bauxite leachates by bentonite–polymer composite geosynthetic clay liners

Peng

et al. 2020

RSC Adv.

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“…The common method adopted is the "compatibility test", in which the sample is permeated with a leachate similar to that anticipated. Factors influencing the hydraulic conductivity of GCLs have been studied through extensive compatibility tests [25,53,55,[59][60][61][62][63][64][65]. Generally, the hydraulic conductivity can be affected by both internal and external causes.…”

Section: Hydraulic Conductivity and Chemical Compatibilitymentioning

confidence: 99%

State-Of-The-Art Review of Geosynthetic Clay Liners

Kong

Chai

et al. 2017

Sustainability

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An important component of modern landfills is the liner system for the prevention of leachate contamination of surrounding ground. Among landfill liner systems, geosynthetic clay liner (GCL) has gained widespread popularity across the world because of its lower hydraulic conductivity as well as its ability to self-heal local damage, which is almost unavoidable in the field. Over the past few decades, numerous studies have been conducted to examine the performance of GCLs, particularly in regard to hydraulic conductivity, chemical compatibility, water-swelling, self-healing capacity, diffusion characteristics, gas migration, and mechanical behavior. In this paper, a brief introduction on modern GCL products is firstly given. Subsequently, the main findings of previous publications on the critical properties influencing the long-term performance of GCLs are summarized in a comprehensive manner. Finally, further research perspectives on polymer-treated GCLs are presented. This paper provides general insights that help readers gain a state-of-the-art overview of GCLs and trends for future development.

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Effect of ammonium on the hydraulic conductivity of geosynthetic clay liners

Cited by 50 publications

References 18 publications

Polymer Elution and Hydraulic Conductivity of Bentonite–Polymer Composite Geosynthetic Clay Liners

Polymer Elution and Hydraulic Conductivity of Bentonite–Polymer Composite Geosynthetic Clay Liners

Attenuation of Cr/Pb in bauxite leachates by bentonite–polymer composite geosynthetic clay liners

State-Of-The-Art Review of Geosynthetic Clay Liners

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