Abstract
In this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The laboratory permeation tests with high ionic strength salt solutions reveal that the GB fails to seal and exhibits a significant mechanical collapse under different applied stresses. The applicability of GB in the form of geosynthetic clay liners as the bottom liner facilities in landfills that produce high ionic strength salt leachates, therefore, remains a serious concern. We propose an additional barrier system based on kaolin, for the first time, to address this problem. The proposed kaolin-GB layered system performs satisfactorily in terms of its sealing and swelling ability even in adverse saline conditions and low overburden stresses. The kaolin improves the osmotic efficiency of the self and also helps the underlying GB layer to seal the inter-granular voids. The estimated design parameters by through-diffusion test suggest that the kaolin-GB layered system effectively attenuates the permeant flux and suitable as a landfill liner.
Highlights
In this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste
The permeation rate of water through GB was very high in the initial 30 min, but the rate significantly dropped after 90–100 min due to the sealing of the intergranular voids in GB
Complete sealing of the inter-granular voids could not be achieved in the presence of 0.5 M KCl, and the measured fluid permeation rate was higher than the limiting value (1 × 10–9 m/s) even after the equilibrium
Summary
We assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The behaviour of GCLs due to exposure to such inorganic salt leachates under different overburden stresses arising from the waste load is vital for the overall hydraulic and mechanical stability of the landfills. These overburden stresses vary from low to high during the initial phase of waste disposal to the closure of the landfill[22,30,31]. The osmotic efficiency of compacted kaolin improves further in high ionic strength inorganic salt s olutions[32]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
