There are various kinds of liners that can be found within a sanitary landfill, each serving their own particular purpose within a system of filtration and containment. BTL’s ArmorPro series includes strong, flexible, and chemically resistant liners. These liners are designed to outlast HDPE and other popular liner materials in even the most extreme conditions and against the toughest contaminants. The XR-3 geomembrane is an affordable, durable option for landfill liners. It’s constructed with a nylon woven reinforcement layer sandwiched between EIA coatings that are extremely stable even in an adverse environment. XR liners offer maximum containment and protection for even highly challenging substances. Whenever it’s necessary to minimize or prevent toxic leachate from moving into nearby rivers, underlying aquifers or surrounding soil, the ArmorPro series of XR liners from BTL Liners are an outstanding choice.
Compacted Clay
Compacted clay liners use natural clay sourced from local clay deposits and are constructed onsite rather than requiring installation. The construction sequence of a CCL is labor intensive, and includes preparation of the foundation, optimizing the moisture content of the clay, placement of the materials and finally compaction to minimize any tiny air pockets, cracks or other potential faults in the seal. It’s also critical during construction to maintain the optimized moisture content of the prepared clay until it has been covered with water, since drying out leads to cracking, shrinkage and other potential causes of leaks.
CCLs are vulnerable to seismic activity and cannot withstand much differential settlement in the foundation without cracking. While most synthetic liners are resistant to acids, bases, and salts present in tailing dam seepage, clay may be vulnerable to interactions with certain leach solutions. In such a case, associated weakening of the seal could eventually lead to impoundment failure. Perhaps most importantly, even if faults are promptly discovered, repair of a damaged compacted clay liner is extremely difficult, if not impossible. In modern landfills, compacted clay liners by themselves are rarely acceptable. Instead, they are frequently employed as supportive underlayment underneath a high quality geotextile liner.
Geosynthetic Clay
GCL is a hybrid product, composed of a layer of bentonite clay sandwiched between two geosynthetic layers. When this type of liner is exposed to water, the bentonite absorbs the water and expands up to 30 times in volume until it forms a gel, which effectively prevents passage of liquids. The gel-like consistency of the clay in this liner means it’s less vulnerable to uneven settling or shifting and it’s fairly well suited to self-repair in certain situations. However, since the bentonite is held between layers of geomembranes, the long-term effect of abrasion on the liner and possibility of punctures should be considered as well.
Geomembranes
These include high density polyethylene (HDPL), polypropylene (PPL), and polyvinyl chloride (PVC). Different liner products and configurations are typically evaluated based on price, performance and availability, as well as their reputation for reliability over time. Since geomembranes can be custom fabricated and shipped directly to the site for quick installation, the savings can be substantial when compared to other liner options that must be constructed on-site, like in the case of concrete or clay.
Durability
Waste materials found within waste lagoons are typically heavy and corrosive, tending to distort non-reinforced liner products, stretching them like a balloon. This increases wear and risk of tears or impacting the ability of liquids to flow within a collection layer. Reinforced polyethylene (RPE), in particular, is designed to resist this type of expansion under heavy loads. One excellent example is BTL’s innovative AquaArmor line, which combines layers of woven HDPE or other reinforcing layers to limit stretching and bulging while sandwiched between engineered coatings to provide exceptional toughness.
Chemical and temperature effects on geomembranes can also alter their performance, and selection of liners that are inert to possible chemicals and chemical processes in a storage facility is critical. Consideration of possible (not simply typical) temperature extremes should also be considered. As the effects of changing weather patterns emerge, it has become clear that planning and designing for a range of only 100-year temperature or rainfall extremes is insufficient.
Punctures and increased wear from waste materials such as crushed rock or broken plastics can impact the integrity and longevity of a liner. This can be mitigated by the addition of a small layer of sand between the rock and liner or the use of a thin cushioning underlayment, but the use of a reinforced liner specifically engineered to withstand abrasion and wear, such as BTL’s AquaArmor, is advised.
Installation
Geomembrane liners are fabricated and shipped to a site in large rolls. They can be customized to fit the specific topography of a site, permitting rapid installation. Liners of this type are relatively thin, however, and care must be taken to avoid damage before, during and after installation. In fact, most leaks involving geosynthetics arise from defects in installation - usually at joints and seams. Rigorous quality control and assurance programs exercised during construction and installation should eliminate these issues, resulting in a well-engineered system which virtually eliminates the risk of environmental contamination through seepage or leaks.
Selecting a liner
The use of a high-quality product and a team of experienced, professional installers can ensure that installation is faultless, all joints and seams are optimal and no potential wear points are overlooked. BTL Liners has been recognized as an industry leader in RPE liner innovations for 40 years. Our team of experts can help you select the best geomembrane for your containment specifications based on each section of treatment or processing step. No matter what solution you need, we can help you find and install the right liner.
