A secure or sanitary landfill is a carefully built and lined depression in the ground, or a landfill built on top of the ground, into which wastes are put. Whichever it is, the aim is to avoid any hydraulic connection between the wastes and the encircling environment, particularly groundwater. Essentially, a landfill is a bathtub in the ground , a double-lined landfill is one bath inside another. Bathtubs can leak in two ways : out the bottom or ott. HDPE landfill liners are the most well liked choice for lining landfills internationally and the best HDPE lining systems are generally “composite” systems with a mix of HDPE surface above a clay type material for extra protection.
There are 4 urgent elements in a secure landfill : a bottom liner, a leachate collection system, a cover, and the natural hydrogeologic setting. The natural setting can be selected to reduce the likelihood of wastes escaping to groundwater underneath a landfill. The 3 other elements must be engineered. Each one of these elements is important to success.
GUNDLE geomembranes were one of the first manufactured and are produced using high density polyethylene ( HDPE ). GUNDLE is produced in diverse thicknesses and with either smooth or structured surfaces.
The acclaim for High Density Polyethylene ( HDPE ) is essentially due to its low initial material cost and excellent chemical resistance. This permits thicker sections to be used compared to other geomembrane materials. A thick, durable, HDPE liner can be placed in exposed applications where the price of other materials would be prohibitory. HDPE has fantastic chemical resistance which is frequently the driving force behind the choice of HDPE. HDPE is a field assembled lining material that cannot be practically built in the shop .
Legislations in several nations around the planet have driven the market for landfill liners making waste containment the single biggest use for HDPE liners. HDPE landfill liners are in most cases cost-effective, have glorious chemical resistance to most chemicals, and have predicted maunfacturer quoted lifetimes ( in a properly designed and built landfill ) of hundreds of years. Dependent on the level of containment required HDPE can be mixed with other lining materials ( or other HDPE layers ) to form multi-layer landfill liners for dangerous waste applications. HDPE is infrequently utilized in landfill caps however a low friction angle boundaries its application on steep slopes.
All HDPE projects, irrespective of size, must be installed by trained installers. HDPE is a versatile material which is used widely across all applications. One of the key uses of HDPE is for landfill base liners where its chemical resistance is used to good effect. HDPE can also be utilized in a mess of secondary containments, pond linings, and water containment projects. HDPE is best used as an exposed lining material, and has the UV resistance needed for years of outstanding service. The primary use of HDPE for the previous couple of years has been in waste containment.
HDPE materials practically do not change their properties inside temperature go from -60 degrees C to +60 degrees C. They are resistant to the most chemical substances : acid, salts, alkaline, fats and for example. HDPE membranes are not spoilt by fungus, microbes, are resistant against plant root growing and ultraviolet radiation and do not affect the standard of drinkable water.
The makers claim that world experience of HDPE application confirms sturdy life-span of HDPE geomembranes, not less than fifty years.
The high density polyethylene surfaces are usually made of 97.5% polyethylene, 2.5% carbon black and other stabilizers for UV protection, aging protection, anti oxidants. The product does not contain softening agents that would migrate in time.
This material offers the highest tensile strength, impact, tear and puncture resistance. It was very good ESCR ( Environmental Stress Cracking Resistance ) and the highest resistance to chemicals. Its downside is its rigidity which makes handling and installation more difficult. HDPE is the in most situations the number one choice in landfill lining, insulation of chemical plants, roads, gas stations etc . As well as in mining, due to its chemical resistance.
There are nonetheless many other geomembranes like Puraflex. Puraflex is a real example of a new hydrocarbon and chemical resistant barrier membrane designed for containment, separation, environmental and groundwater protection projects. Its proved resistance to hydrocarbons and toxic commercial chemicals provides a inexpensive answer for brownfield developments.