What is Bentonite?

Sodium Bentonite is soft clay of volcanic origin with a number of diverse uses. When exposed to water it expands by approximately 28% by volume and can thus be used to provide a water seal. Bentonite clay is used in the manufacture of geosynthetic clay liners (GSL). Typically a polypropylene geotextile is impregnated with Sodium bentonite. GSL's are supplied in panels and rolls. The matting is not unlike carpet underlay, which can be overlapped and laid on a substrate to form ponds and lakes. The use of Bentonite was traditional in canal building.

It can be more costly than a membrane but is self-sealing and is more conducive to forming a more natural edge to a water body. This can enhance plant growth making it a more ecologically friendly option. If the location of a leak can be detected it is very easy to repair with a powdered form.

Sodium bentonite expands when wet, possibly absorbing several times its dry mass in water. It is mostly used in drilling mud for oil and gas wells and for geotechnical and environmental investigations.

The property of swelling also makes sodium bentonite useful as a sealant for industrial purposes, especially targeted for the sealing of subsurface disposal systems for spent nuclear fuel and for quarantining metal pollutants of groundwater. Similar uses include making slurry walls, waterproofing of below-ground walls and forming other impermeable barriers (e.g. to plug old wells or as a liner in the base of landfills to prevent migration of leachate into the soil).

The A.G.A. Group utilise these important benefits to line new pond and lakes, however importantly these same benefits of the material are useful to repair leaking structures and water bodies