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Why are GCLs often used for liners in landfills?

News | July 21, 2023 | By:

Ongoing management of landfill sites involves complex environmental challenges and requires strict compliance with certain guidelines. Managing issues such as leachate, runoff, gases, and other by-products of the waste management process have traditionally been managed by lining and capping cells with clay. Geosynthetic Clay Liners (GCLs), however, offer an alternative to traditional clay lining of landfill containment structures. GCLs provide a neater, easier, and more robust way to cap landfill cells, enclose contaminated soil, and protect groundwater for environmental conservation.

Due to their flexibility and ease of installation, GCLs are used widely by landfills across Australia, offering immediate sealing and a robust, reliable, long-term barrier against gas and liquid leaks. When compared to clay lining, which can be messy, time-consuming, and prone to defects, GCLs offer an engineered solution that is quick to install, cost-effective and provides a long-term hydraulic barrier. This ensures that responsible landfill operators can deliver good waste management practices for many years to come.

Immediate sealing capability

With a layer of sodium bentonite sandwiched in between two layers of geotextile, the bentonite swells in contact with water and provides a natural sealant effect. This self-sealing and re-healing capability provides protection against ion and gas exchange, provides a barrier against roots, and reduces bentonite erosion from high water pressures and gravelly subsoils.

A GCL like Bentofix® offers both immediate sealing and long-term in-situ performance thanks to this high-swelling sodium bentonite powder. Different versions with the inclusion of a durable PE coating or scrim reinforcement provide additional protection for specialist applications.

Shear resistance

The uniform needle-punched construction of special coated GCLs like Bentofix® helps to improve multi-directional shear strength and internal friction angles. An additional surface polyethylene (PE) coating is applied in a liquid state and then allowed to solidify on the carrier geotextile, permanently locking the fibres and increasing the pull-out resistance as well as the internal shear strength.

Cost-saving alternative to compacted clay

One of the key benefits of GCLs is the ability to offer landfill engineers an engineered equivalent to clay without the expensive installation and quality control costs associated with this traditional method. The cost-effective nature of GCLs makes them a natural choice for landfill designers, helping to reduce transport costs, construction costs and labor requirements.

Additionally, GCL liner systems are typically not as thick as compacted clay liner systems, meaning engineers can design landfills that maximize capacity while protecting the surrounding groundwater and environment.

Global Synthetics offers a wide range of geosynthetic clay liners that are compatible with the complex environments and contaminants that are often encountered in landfill sitesGet in touch with their engineering team for more information or take a look at their information on Bentofix®.

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