What is Geomembrane lining?

A geomembrane liner is an impermeable polymer sheet used to keep liquids or vapour in, or out, of a structure or the ground. It is used for primary containment (a pond, a landfill cell, a canal) and secondary containment (a lined bund around a tank). Grades differ in polymer, thickness, surface texture and chemical resistance, and the choice follows from what is being contained and how the liner will be loaded and exposed.
Geomembrane liners are used across environmental protection, mining, oil and gas, and waste handling.

General Applications for Geomembrane Liners

Secondary Containment

The most common use is containing hazardous materials, as either the primary or the secondary barrier. Refineries, fuel depots, airports and similar facilities need secondary containment for fuel, oil, sludge and chemicals, so that a leak from a tank or pipe stays out of the soil and groundwater. Liners are fabricated and welded on site to line bunds around underground and above-ground tanks and areas for portable chemical storage.

When choosing a liner for this work, check four things: resistance to UV, weather and repeated thermal expansion and contraction if it will be exposed; enough thickness and puncture resistance to take the weight of the tank and site traffic; chemical compatibility with the stored product over long contact (HDPE has the broadest chemical resistance of the common polymers); and a seaming method that can be tested.

Landfills

A landfill liner has to stop leachate reaching the groundwater beneath it. Geomembranes line the base and sides of solid-waste landfills, in single or double (primary and secondary) liner systems, and form the cap when a cell is closed. Temporary geomembrane sheets can also serve as an alternative daily cover in place of a soil layer, to control odour, vectors, fire, litter and scavenging, and to divert rainwater away from open waste so less leachate is produced.

Roads and Highways

On roads and highways, a geomembrane can act as a waterproofing layer beneath the pavement, keeping water out of moisture-sensitive subgrade such as expansive clay. In cold regions it is also used under roads to stop de-icing salt reaching the soil and groundwater.

Vapor Barriers

In buildings, a geomembrane under the floor slab and against basement walls stops ground moisture rising into the structure, which would otherwise cause damp, mould and long-term damage to finishes and reinforcement. On contaminated land the same layer keeps soil gases and chemicals from entering the building and stops spills from the building reaching the ground. Preventing damp at the start costs less than repairing it later.

Geomembranes are used in environmental, hydraulic, transport, oil and gas, and waste work. Most are continuous polymer sheets. Where a large area is lined, the panels are joined on site: polyethylene by thermal welding, PVC by thermal or solvent welding. Because panels can be welded together, a liner can cover anything from a backyard fish pond to an area the size of a football field.

Common uses include:

• Liners for drinking water and reserve water storage (including emergency water supplies at nuclear plants)
• Fish pond and aquaculture liners
• Liners for waste liquids such as sewage sludge, and for radioactive or hazardous liquid waste
• Agricultural water storage ponds and canals
• Liners for canals carrying wastewater
• Primary, secondary and tertiary liners for solid-waste landfills and waste heaps
• Linings for emergency spillways
• Waterproofing in tunnels and pipelines
• Flexible tanks for carrying liquids on trucks and for moving water by sea
• Below highways to prevent pollution from de-icing salts
• Under and beside highways to capture hazardous spills

Geomembranes go wherever water, wastewater, vapour or a hazardous liquid must stay where it is put.

Geomembrane Liner Supplier

Ocean Global manufactures geomembrane liners to project requirements. The range includes:

LLDPE: Linear Low-Density Polyethylene
HDPE: High-Density Polyethylene
PVC: Polyvinyl Chloride
GCL: Geosynthetic Clay Liner (a bentonite liner, often laid under a geomembrane as a composite liner)

Once the material is chosen, thickness is the next decision. Our guide to choosing geomembrane thickness explains micron, mm and mil, what extra thickness changes, and the usual grades for ponds and landfills.

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