The Influence of Salt Solution on Morphological Changes in a Geosynthetic Clay Liner

Abstract

Morphological variations of geosynthetic clay liner (GCL) samples, hydrated with two different permeates, distilled water and NaCl solution (100 mM concentration), were observed in detail using microscopic analysis. After the GCL samples were hydrated with the NaCl solution, they were observed with an optical microscope. While the surface of the treated GCL samples was similar to the surface of the untreated GCL, a crystal deposit was found on the surface of the treated samples. Using a scanning electron microscope (SEM), a more solid appearance was observed for the bentonite particles contained in the GCL after the sample was hydrated with distilled water in comparison to the GCL sample that was hydrated with the NaCl solution. It appears that salt solution hydration results in less swelling of the bentonite particles. Furthermore, the energy-dispersive X-ray spectrometer (EDS) results showed that distilled water hydration had no effect on the distribution of the elements contained in the GCL samples. However, bound chlorine was observed, which demonstrated that the bentonite particles had absorbed the NaCl solution. In addition, changes in the hydraulic conductivity of the hydrated GCL samples were also observed.

Hydraulic Stability of Fly Ash-Bentonite Mixtures in Landfill Containment System

“…The mixtures that were hydrated using salt are known to have greater hydraulic conductivity compared to the mixtures that were permeated with non-alkaline solutions. Immersion using saline solution will cause an increase in hydraulic conductivity three times higher than the previous value (Budihardjo, 2016). The addition of salt concentration will reduce the compression index, which occurs because of the decrease in the thickness of the double layer diffuse due to the salt being introduced in the pore fluid so that the maximum dry density increases.…”

“…The variation of bentonite used in this study is in line with the research conducted by Pandey and Jain (2017) which stated that the use of bentonite by 20% has a permeability coefficient of 0.9 x 10-7 cm.s -1 (Pandey and Jain, 2017). Inorganic salts, which were used to hydrate bentonite liners, are known to reduce swelling volume, liquid limit, compression index, increase hydraulic conductivity (Budihardjo, 2016;Shariatmadari et al, 2011) and increase the desiccation cracking in the vertical liner. Cracking increases the value of bentonite permeability in the liner system.…”

Effect of Pore-Water Salinity on the Electrical Resistivity of Partially Saturated Compacted Clay Liners

“…Landfill facilities that usually have a cover and liner system are constructed to store the municipal solid wastes (MSWs) to protect the environment [1]. e compacted clay liners (CCLs) in the liner system are constructed as a layer of hydraulic barrier to separate the leachate or toxic pollutants from the MSW into the subsoils or groundwater, to ensure good conditions of the subsoils [2][3][4][5][6]. e CCLs are constructed of the natural soils or by combining them together with some other geosynthetics (e.g., geomembrane, geotextiles, and geosynthetic clay liners) based on different hazardous levels of MSW [7].…”