The single most common and essential use for a geomembrane is lining. Without a flexible and impermeable layer of geomembrane, it’s much harder and more expensive to build a pond, tank, containment area, landfill, or other facility that must hold liquids. Other methods for building a leak-proof container can take weeks, to months, longer to install than a flexible geomembrane. Other devices are also much more prone to leaks. Liners for sewage treatment ponds and landfills were some of the earliest uses for the first geomembranes, and these applications have driven the development of new materials for decades.
Categorizing Geomembrane Liners by Water Safety
For ponds used to grow fish and plants, store water for irrigation, and hold potable water for human or animal consumption, you must choose an appropriate liner rated for that purpose. Other materials can leech chemical by-products into the water that lead to slow growth and even dead fish and plants. Liners safe for potable water are fish and plant safe as well, but not all fish-safe liners are automatically a good choice for storing potable water. Even if the liner is buried or installed below concrete, it may need to still meet safety guidelines to qualify for state and federal installation standards. Materials like reinforced polyethylene (RPE) and EDPM are both fish and plant safe and come in various potable water approved formulations. PVC liners are much more likely to release toxins hazardous to fish and plants, and only some formulations are approved for long-term contact with potable water.
Preventing Fluid Exchange from Both Directions
Choosing an impermeable geomembrane liner stops the opportunity for fluid exchange, in both directions, when applied between the soil and the liquids being contained. Liquids can’t leak out through the capillary action of porous concrete, or soil, when there’s a geomembrane in the way. Fluids also can’t mix in from the surrounding soil and contaminate a pure product or an important potable water supply. Other lining methods, like clay and spray-on barriers, can’t compare when it comes to blocking fluids from seeping in from outside the containment area.
Dealing with the Most Challenging Storage Demands
With the right material selection, it’s possible to install a geomembrane liner that can handle some of the most challenging storage situations. From nuclear waste to highly corrosive runoff from mining and refining operations to retaining and storage ponds around the world, it is pertinent to select a liner that will withstand severe conditions with minimal maintenance. Products like BTL Liner’s ArmorPro can handle a wide range of challenges thanks to its combination of HDPE and LDPE layers in a single geomembrane. No reactive chemical mixture or corrosive waste will compromise the integrity of your containment system when you install a geomembrane matched to the challenge.
Product Loss Through Leakage and Evaporation
Unlined holding ponds and tanks can leak a surprisingly high amount of valuable chemical and fertilizer products. Even with a clay or spray-on liner, these containers tend to eventually lose fluid which reduces the profit generated by a chemical mixing or agricultural production. A pond or tank without a liner is also much harder to seal with a cover; increasing the rate of evaporation resulting in product loss. Unless you’re holding fluids in open containers to take advantage of natural evaporation, you’ll want a cover to control treatment plans and limit loss. There’s little point in installing a tight-fitting cover if there’s no liner below to stop loss underground. Pair both geomembrane liners and covers together to create a complete system.
Chemical and Abrasion Resistance
While all geomembranes need high durability regardless of their eventual use, materials installed as liners specifically need high abrasion resistance as well. These membranes are stretched across bare soil or concrete in most installations, and even relatively smooth surfaces can cause a lot of wear to liner materials. Rocks and sharp roots left in the soil after clearing and grading have the potential to snag the liner material. If a quality liner isn’t used in these conditions, rips and punctures can result. A high abrasion resistance simplifies installation and ensures there’s no leaks to chase down within the first few weeks of use.
Chemical resistance is also essential for many installations. Reactions between some geomembrane materials and the chemicals stored over them can result in peeling seams, cracking material, and an overall shorter lifespan of the liner. PVC was one of the first materials to offer a high level of chemical resistance in a flexible polymer liner. Now most engineers prefer reinforced polypropylene (RPP) and reinforced polyethylene (RPE) because these materials offer superior abrasion coupled with chemical resistance.
Secondary Containment and Impoundment
Secondary containment systems are primarily installed anywhere hazardous chemicals like fuel, oil, and certain waste products are stored or transferred. Even if you’re just loading some manure slurry into a tank or delivery truck, you may need to install a geomembrane liner to control spills and leaks. Containment designs and methods vary, but some techniques call for installing geomembranes under concrete or using it as a temporary pad along with pop-up supports for the sides. Geomembranes are also essential for designing fracking and well-drilling impoundments that meet all EPA regulations for hazardous material storage. Impoundments are containers or ponds used to hold drilling waste products until they’re either removed for disposal elsewhere, reused in the operation, or treated on-site. Since most of these impoundments hold materials that are highly toxic and/or corrosive, they must be built with care and the right liner system.
Agricultural Liners for Both Crop and Livestock Production
There are dozens of uses for geomembrane liners in the agriculture industry, but irrigation and manure slurry storage combined, make up the majority of the installations. Irrigation systems, involved ponds, and canals all benefit from an impermeable liner like AquaArmor from BTL Liners. Water loss through porous and sandy soils or cracked clay and concrete liners can waste thousands of gallons of valuable irrigation water per day, in addition to natural evaporation from open storage ponds. Combine a proper geomembrane liner with a floating cover and watch your water costs drop during the driest months of the year. On ranches and concentrated feeding operations producing livestock, geomembrane liners play an essential role in the manure lagoons by keeping highly concentrated runoff from affecting nearby soil and water.
Why Seam Sealing Matters Most with Geomembrane Liners
There are many geomembrane applications that result in great seam pressure. The weight of soil, water, or anything else above the liner material stresses seams over years of use. If not sealed properly, a burst seam can lead to a large loss or contamination scenario that brings in EPA inspectors. When selecting a geomembrane for a specific liner project, check the methods used for sealing the seams and the durability of the finished join. Weak seams lead to lost product, mixing of reactive chemicals, and contamination of the surrounding soil. Never choose a material that is hard to test after sealing, since you’ll have to wait until there’s an obvious leak to discover any problems. All of the products available from BTL Liners are easily vacuum or air lance tested to verify there’s a leak-proof seal along each seam.
The Importance of Very Low Permeability Ratings
With all materials featuring some kind of pore at the molecular level, it’s technically impossible to create a truly impermeable lining that blocks all gases and liquids. However, plenty of geomembrane liner materials offer practical impermeability by achieving such a low permeability rating that nothing will get through it under any real-life circumstances. Most geomembranes have a minimum impermeability rating of 1 x 10-10, while some achieve up to a 1 x 10-14 impermeability rating with proper installation. No other liner methods can compare to this level of control over liquid and gas penetration. Even vapors can’t travel through most geomembranes, making it essential for lining containment areas for the most hazardous materials. Both thickness and the material used for the geomembrane play a role in determining its final permeability rating; with thicker products offering greater impermeability. That’s why wastewater containment applications call for up to double the minimum thickness as required for clear or freshwater storage designs.
