Effect of Freeze-Thaw Cycling Concurrent with MSW Landfill Leachate on the Hydraulic Conductivity of Geosynthetic Clay Liner

2018 ◽  
pp. 658-663
Author(s):  
Bao Wang ◽  
Bin Chen ◽  
Dou Tongtong ◽  
Lou Wang
Keyword(s):  
Hydraulic Conductivity ◽  
Landfill Leachate ◽  
Geosynthetic Clay Liner ◽  
Clay Liner ◽  
Freeze Thaw ◽  
Msw Landfill

Improving hydraulic performance and durability of sandwich clay liner using super-absorbent polymer

2017 ◽  
Vol 21 (3) ◽  
pp. 1055-1071 ◽  
Author(s):  
Niloofar Salemi ◽  
Seyed Mehdi Abtahi ◽  
Mohammad Ali Rowshanzamir ◽  
Seyed Mehdi Hejazi
Keyword(s):  
Hydraulic Conductivity ◽  
Hydraulic Performance ◽  
Partial Replacement ◽  
Sodium Polyacrylate ◽  
Self Healing ◽  
Super Absorbent Polymer ◽  
Geosynthetic Clay Liner ◽  
Clay Liner ◽  
Swell Index ◽  
Absorbent Polymer

The hydraulic performance and durability of geosynthetic clay liner containing various amounts of sodium polyacrylate polymer are experimentally studied. Sodium polyacrylate, generally known as a super-absorbent polymer, is a polymeric material with a potential of high water absorbance due to its chemical structure. In this study, sodium polyacrylate powder is used as a partial replacement of bentonite as much as 3%, 5% and 7% by the weight of bentonite. For comparison, the hydraulic performance of geosynthetic clay liner without super-absorbent polymer is also experimented. Atterberg limits, free swell index, hydraulic conductivity, self-healing capacity and wet/dry cycle tests are conducted in order to assess how super-absorbent polymer can affect the performance of geosynthetic clay liners as landfill liners and covers. The results show that the hydraulic conductivity and self-healing capacity of geosynthetic clay liner are relatively enhanced by super-absorbent polymer inclusion. The results of wet/dry cycle test show that using super-absorbent polymer as a partial replacement of bentonite considerably improves the durability of geosynthetic clay liner against wet/dry cycles. Geosynthetic clay liner containing super-absorbent polymer shows a negligible increase in hydraulic conductivity while there is a noticeable increase in hydraulic conductivity of specimen without super-absorbent polymer after 10 cycles of wetting and drying.

Freeze–thaw cycling concurrent with cation exchange and the hydraulic conductivity of geosynthetic clay liners

2014 ◽  
Vol 51 (6) ◽  
pp. 591-598 ◽  
Author(s):  
Gregory P. Makusa ◽  
Sabrina L. Bradshaw ◽  
Erin Berns ◽  
Craig H. Benson ◽  
Sven Knutsson
Keyword(s):  
Hydraulic Conductivity ◽  
Cation Exchange ◽  
Pore Water ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Chemical Changes ◽  
Clay Liner ◽  
Freeze Thaw ◽  
Exchange Complex ◽  
Before And After

A study was conducted to assess the effect of cation exchange concurrent with freeze–thaw cycling on the hydraulic conductivity of a geosynthetic clay liner (GCL). GCLs were prehydrated by contact with silica flour moistened with synthetic subgrade pore water and subsequently permeated with a solution representing the pore water in the cover soil over a tailings facility. Control tests were conducted using the same procedure, except deionized (DI) water was used as the permeant liquid to preclude cation exchange from the permeant liquid. The GCLs were subjected to 1, 3, 5, 15, and 20 freeze–thaw cycles, and the hydraulic conductivity and exchange complex were determined before and after freeze–thaw cycling to assess chemical changes that occurred during freezing, thawing, and permeation. GCLs undergoing freeze–thaw cycling experienced little to no cation exchange through 5 freeze–thaw cycles. After 20 freeze–thaw cycles, 50% of the sodium (Na+) initially in the exchange complex was replaced by calcium (Ca2+). Dissolution of calcite within the bentonite is a likely source of the Ca2+. Hydraulic conductivity of the GCLs exposed to freeze–thaw cycling was lower than the hydraulic conductivity of a new GCL permeated with DI water (<2.2 × 10−11 m/s). A small increase in hydraulic conductivity (∼2.3 times), which may have been caused by cation exchange, occurred between 15 and 20 freeze–thaw cycles, but the hydraulic conductivity remained below the hydraulic conductivity of a new GCL unexposed to freeze–thaw cycling and permeated with DI water.

scholarly journals USE OF GEOSYNTHETIC CLAY LINER AS A WATERPROOFING BARRIER IN SANITARY LANDFILLS

2019 ◽  
pp. 115-124
Author(s):  
Caroline Visentin ◽  
Pedro Nicola Zanella ◽  
Bruna Koppe Kronhardt ◽  
Adan William da Silva Trentin ◽  
Adeli Beatriz Braun ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Government Agencies ◽  
Solid Waste Disposal ◽  
Geosynthetic Clay Liner ◽  
Clay Liner ◽  
Sanitary Landfills ◽  
Landfill Sites ◽  
Leachate Composition ◽  
Proper Performance ◽  
Soil And Water

One of the main sources of soil and water (superficial and subterranean) contamination is the inadequate solid waste disposal. In this sense, sanitary landfills have great importance for environmental protection, and in these systems, the geosynthetics materials, such as the Geosynthetic Clay Liner (GCL), are widely employed. However, for landfills with leachate recirculation, the application of GCL is vetoed by many government agencies. In view of this, this study sought to provide an analysis of recent advances in application of GCL in landfill sites. For this reason, the main configurations of landfills and characteristics of its leachate were presented, as well as of the GCL by means of case studies applied to the context. The results indicated that the most important parameter to be evaluated in GCL performance is its hydraulic conductivity, which can be influenced directly by leachate composition (conventional and recirculated) as to the presence of cations and anions. Thus, it is concluded that the evaluation of these characteristics is essential to ensure the proper performance of GCL in landfills.

Changes in geosynthetic clay liner (GCL) properties after 2 years in a cover over arsenic-rich tailings

2013 ◽  
Vol 50 (3) ◽  
pp. 326-342 ◽  
Author(s):  
M.S. Hosney ◽  
R. Kerry Rowe
Keyword(s):  
Hydraulic Conductivity ◽  
Cation Exchange ◽  
Divalent Cations ◽  
Climatic Conditions ◽  
Polypropylene Film ◽  
Geosynthetic Clay Liner ◽  
Clay Liner ◽  
Cover Soil ◽  
Test Cover ◽  
Nonwoven Geotextile

A test cover comprised of three different needle-punched geosynthetic clay liner (GCL) products and covered with up to 1 m of cover soil (gravelly sand) was built over arsenic-rich tailings at a former gold mine in Nova Scotia, Canada, to evaluate the performance of the GCLs under local climatic conditions. Of the GCLs examined, one had untreated and two had polymer-enhanced natural sodium bentonite. The three GCLs each had different carriers: one with a woven geotextile, one with a scrim-reinforced nonwoven geotextile, and one with a woven geotextile laminated with a polypropylene film. At some locations, each type of GCL was placed in direct contact with the tailings. At other locations, each GCL was separated from the tailings by 0.15 m of cover soil. Samples of each GCL, tailings, and cover soil were recovered 1 and 2 years after construction. Tests show that the GCL with untreated bentonite maintained a low hydraulic conductivity (≤5 × 10−11 m/s) at locations where there was ≥0.7 m of cover soil above the GCL even though there was significant cation exchange of the sodium in the GCL with divalent cations in the tailings-soil porewater (the mole fraction of sodium (exchangeable sodium percentage (ESP)) decreased from 65% to 10%–17%). The GCL with polymer-enhanced bentonite had a lower hydraulic conductivity (≤3 × 10−11 m/s under ≥0.7 m of cover soil above the GCL) and experienced less cation exchange (ESP decreased to 19%–28%) than the standard GCL. The other GCL with polymer-enhanced bentonite and a carrier geotextile coated with a geofilm demonstrated the best hydraulic performance regardless of the thickness of cover soil or presence of an initially uncontaminated foundation layer. The presence of a foundation layer between the GCL and tailings impeded the migration of arsenic from the tailings into the GCLs. All GCLs were serving as an effective barrier to arsenic migration.

scholarly journals Hydraulic conductivity of a dense prehydrated geosynthetic clay liner

2015 ◽  
Vol 22 (1) ◽  
pp. 138-148 ◽  
Author(s):  
F. Mazzieri ◽  
G.Di Emidio
Keyword(s):  
Hydraulic Conductivity ◽  
Geosynthetic Clay Liner ◽  
Clay Liner
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