Environmental Containment with Ocean Geosynthetic Clay Liner 6 MM in Odisha Landfill Project

At a landfill project in Odisha, Ocean Non Wovens supplied and installed 6798 SQM of Ocean Geosynthetic Clay Liner 6 MM as a low-permeability barrier for environmental containment and seepage control.

A Geosynthetic Clay Liner (GCL) is a layer of sodium bentonite held between two geotextile layers. It replaces or supplements the thick compacted clay layer used in older landfill designs, whose performance depends heavily on the local soil and on how well it was compacted on site.

Project overview

• Project Type: Landfill Infrastructure Project
• Location: Odisha
• Product Used: Ocean Geosynthetic Clay Liner 6 MM
• Quantity: 6798 SQM
• Scope: Supply & Installation
• Application Area: Environmental containment and seepage control

The project needed a low-permeability containment layer that would keep working under the moisture, chemical and loading conditions of a landfill.

How a GCL works

When the bentonite in a GCL hydrates under confinement, it swells into a dense gel with very low hydraulic conductivity, typically in the range of about 1×10⁻¹¹ to 5×10⁻¹¹ m/s. That gel restricts the movement of leachate through the liner. The geotextiles hold the bentonite in place during handling, and in needle-punched GCLs the fibres running through the core give the product internal shear strength for use on slopes.

Compared with a conventional compacted clay layer, a GCL offers:

• Lower hydraulic conductivity in a much thinner layer, so less airspace is lost to the liner
• Faster installation: panels are unrolled and overlapped instead of placed and compacted in lifts
• Consistent quality, because the bentonite content is controlled in the factory rather than in the field
• Self-sealing: hydrated bentonite swells to close small punctures and imperfections

GCL quality is usually checked against ASTM test methods for bentonite swell index (D5890), fluid loss (D5891), mass per unit area (D5993) and flux (D5887).

Why containment uses more than one layer

A single barrier layer has to cope on its own with differential settlement, chemical exposure, moisture variation, mechanical stress and long-term ageing. Modern landfill liners therefore combine geomembranes, geotextiles, drainage layers and GCLs. In a composite liner, the GCL sits directly beneath an HDPE geomembrane: if the geomembrane has a hole, the GCL below it limits how much leachate can pass through. The Odisha project required this kind of integrated containment approach.

Site challenges

Premature hydration

The main risk during GCL installation is premature hydration. If the bentonite takes up water before it is covered and confined, it swells unconfined, can lose bentonite at the edges and may not reach its design performance. Panels laid in a day are normally covered the same day.

Rain during installation

Odisha’s monsoon makes moisture control harder, so rolls have to be stored off the ground under waterproof covers and laid only in dry spells.

Handling and settlement

Careless handling can disturb overlaps and break barrier continuity. Landfills also settle over time, which stresses the containment layers, so installation had to be closely coordinated with the layers above and below.

Installation and quality control

Installation was supervised to keep the barrier continuous. The main steps were:

• Subgrade inspection and preparation: a smooth, firm surface free of stones, roots and standing water
• Controlled panel placement
• Overlap alignment checks, with overlap widths and any supplementary bentonite at end laps as the manufacturer specifies
• Moisture management and protection against premature hydration
• Coordination with the cover layer so the GCL was confined promptly

Overlaps need the most attention. A small gap between two GCL panels creates a local seepage path, so overlaps were inspected throughout installation.

Long-term performance

How well a GCL performs over its life depends on moisture balance, confining pressure, installation quality, exposure and chemical compatibility. The last one matters in landfills: calcium and magnesium in some leachates can exchange with the sodium in the bentonite, which reduces swelling and raises hydraulic conductivity over time. Designers check leachate chemistry when selecting the GCL and usually hydrate it with clean water under confinement before it meets leachate.

Environmental benefits

A GCL replaces a thick layer of excavated and hauled clay with factory-made rolls, cuts construction time and gives a more predictable barrier for groundwater protection. GCLs are used in landfill base liners and caps, mining containment, reservoir lining, industrial and hazardous waste barriers and remediation projects. Without an effective barrier, a landfill risks leachate migration, groundwater contamination, regulatory problems and expensive remediation.

Ocean Non Wovens supplies GCLs, geomembranes and other geosynthetics for waste management infrastructure across India. See the HDPE geomembrane range used alongside GCLs in composite liners, or more case studies.