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Sustainability Study of the Application of Geosynthetic Clay Liners in Hostile and Aggressive Environments

16 Pages Posted: 19 Dec 2012  

Devapriya Chitral Wijeyesekera

Universiti Tun Hussein Onn Malaysia (UTHM)

Eric Wooi Kee Loh

Linton University College

Siti Fathima Diman

Universiti Tun Hussein Onn Malaysia (UTHM)

Alvin John

Universiti Tun Hussein Onn Malaysia (UTHM)

Adnan Bin Zainorabidin

Universiti Tun Hussein Onn Malaysia (UTHM)

Mihaela Anca Ciupala

University of East London

Date Written: December 18, 2012

Abstract

This paper discusses the sustainable performance of geosynthetic clay liners (GCLs) which are popularly specified as “leachate retaining” or as “water proofing” membranes in the geo-environmental construction industry. Geosynthetic clay liners (GCLs) are composite matting comprising of bentonite clay with two covering geosynthetics. These are innovative labour saving construction material, developed over the last three decades. The paper outlines the variety of Geosynthetic Clay Liners (GCLs) can be classified essentially into two distinctly different forms viz; (a) air dry (< 8% m/c) with granular or powdered bentonite or (b) bentonite cake factory prehydrated to a moisture content (~40% m/c) beyond its shrinkage limit and vacuum extruded as a clay cake to enhance its sustainable performance. The dominant mineral in bentonite clay is the three-layered (2:1) clay mineral montmorillonite. High quality bentonites need to be used in the GCL manufacture. Sodium montmorillonite has the desired characteristic of high swelling capacity, high cation exchange capacity and the consequently very low hydraulic conductivity, providing the basis for the hydraulic sealing medium in GCLs. These encapsulate the active montmorillonite clay minerals which depend on the water and chemical balance between the sealing element and the surrounding geo environment. Quantitative mineralogical analyses and an assessment of the adsorbed cation regime, diffusion coefficients and clay leachate compatibility must necessarily be an integral part of the site appraisal to ensure acceptable long term sustainability and performance. Factors influencing the desired performance of bentonite in the GCLs placed in difficult construction and hostile chemical environments are discussed in this paper. Accordingly, the performance specifications for GCLs are identified and the appropriateness of enhancing the cation exchange capacity with polymer treatment and the need for factory prehydration of the untreated sodium bentonite is emphasised. The advantage of factory prehydrating the polymer treated bentonite to fluid content beyond its shrinkage limit and subsequently factory processing it to develop laminated clay is to develop a GCL that has enviable sealing characteristics with a greater resistance to geochemical attack and cracking. Since clay liners are buried in the ground as base liners, capping layer or as structural water proofing membrane, they can easily avoid strict quality and performance monitoring being “out of sight, out of mind!”. It is very necessary that barrier design for leachate containment must necessarily be in accordance with legislative requirement Assessment of long term hydraulic conductivities and clay-leachate compatibility assessment is deemed necessary. The derogatory factors affecting the sustainable performance of the bentonite in GCLs placed in difficult construction and hostile chemical environments are discussed. Sustainability concepts incorporated in waste management practice must aim to achieve 100% recycling and fully implement the handling of solid waste in developing countries with relatively lower labour costs.

Keywords: Bentonite, Cation Exchange Capacity, Geosynthetic Clay liner, Hostile Geo environment, Sustainability

Suggested Citation

Wijeyesekera, Devapriya Chitral and Loh, Eric Wooi Kee and Diman, Siti Fathima and John, Alvin and Zainorabidin, Adnan Bin and Ciupala, Mihaela Anca, Sustainability Study of the Application of Geosynthetic Clay Liners in Hostile and Aggressive Environments (December 18, 2012). OIDA International Journal of Sustainable Development, Vol. 5, No. 6, pp. 81-96, 2012. Available at SSRN: https://ssrn.com/abstract=2191110

Devapriya Chitral Wijeyesekera (Contact Author)

Universiti Tun Hussein Onn Malaysia (UTHM) ( email )

Parit Raja
Batu Pahat, Johor 86400
Malaysia

Eric Wooi Kee Loh

Linton University College ( email )

Ground Floor, Persiaran UTL
Bandar Universiti Teknologi Legenda(BUTL), Batu 12
Mantin, 71700
Malaysia

Siti Fathima Diman

Universiti Tun Hussein Onn Malaysia (UTHM) ( email )

Parit Raja
Batu Pahat, Johor 86400
Malaysia

Alvin John

Universiti Tun Hussein Onn Malaysia (UTHM) ( email )

Parit Raja
Batu Pahat, Johor 86400
Malaysia

Adnan Bin Zainorabidin

Universiti Tun Hussein Onn Malaysia (UTHM) ( email )

Parit Raja
Batu Pahat, Johor 86400
Malaysia

Mihaela Anca Ciupala

University of East London ( email )

Longbridge Road
Dagenham, Essex, RM8 2AS
United Kingdom

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