Why must landfills use 1.5mm/2.0mm HDPE geomembrane?
Landfills continuously generate large amounts of highly corrosive and polluting leachate during the treatment of municipal solid waste. Leachate contains heavy metals, ammonia nitrogen, organic toxins, and pathogens. Once it seeps into the ground, it causes irreversible groundwater pollution, with extremely high remediation costs.
During landfill construction, the bottom and slope impermeable layers must meet extremely high safety and service life requirements.
Global standards consistently stipulate that landfills must use 1.5mm or 2.0mm HDPE geomembranes; this is a mandatory requirement.
Hazards of landfill leachate and the necessity of anti-seepage systems
Landfill leachate has an extremely complex composition.
Landfill leachate typically exhibits the following characteristics:
pH: 4–9 (violent fluctuations, coexisting acid and alkaline corrosion)
Ammonia nitrogen concentration: 1000–3000 mg/L
High COD: up to 40,000 mg/L
Contains heavy metals: Cr, Hg, Cd, Pb
Salinity up to twice that of seawater
Contains corrosive organic acids (such as volatile fatty acids)
Leachate temperatures are consistently 40–60℃, significantly impacting material aging.
Extremely Low Permeability Coefficient (Below 1.0 × 10⁻¹⁴ cm/s)
Landfill leachate contains high levels of pollutants such as COD, heavy metals, and salt. Even the smallest leak can lead to groundwater contamination.
HDPE geomembrane has a dense, non-porous molecular structure, achieving near-zero leakage prevention, making it the preferred material for national standards and international engineering projects.
Excellent Chemical Corrosion Resistance
Leachate environments are characterized by strong acids, strong alkalis, and high salt content. Ordinary materials (such as PVC, EVA, and films) will corrode and age.
HDPE, however, exhibits extremely strong resistance to acids, alkalis, oils, microorganisms, and salts, ensuring stable operation of landfills for over 50 years.
High Aging Resistance and Ultra-Long Service Life (50–100 years)
Landfills have extremely long lifespans, and the anti-seepage system must be used in conjunction with them.
HDPE geomembranes possess the following characteristics:
High-density structure
UV-resistant formulation (containing 2–3% carbon black)
Antioxidants and stabilizers
These properties enable 1.5mm and 2.0mm HDPE membranes to achieve decades of anti-aging capabilities, making them widely used internationally in permanent projects.
High mechanical strength and puncture resistance
Landfill bottoms typically consist of sand cushions, gravel, and protective layers, inevitably resulting in mechanical contact and compaction during construction.
Therefore, the impermeable material must possess:
High tensile strength (≥16–28MPa)
High elongation at break (≥600%)
Why can't we use geomembranes that are 1.0mm or thinner ?
The membrane is easily punctured by stones and debris.
A 1.0mm membrane is very easily punctured during on-site installation by:
sharp objects/stones/roots/construction machinery/high-temperature marks from welding.
Strong puncture and tear resistance
Able to withstand landfill pressure and heavy mechanical compaction
The greater the thickness, the stronger the resistance to mechanical damage; therefore, regulations require bottom impermeable membranes to be ≥1.5mm or ≥2.0mm thick.
Insufficient aging resistance
Thinner thickness:
Lower antioxidant content
Decreased UV resistance
Rapid evaporation loss
High-temperature leachate accelerates aging
10 Advantages of 1.5mm / 2.0mm HDPE Geomembrane
Ultra-low permeability coefficient: Nearly "zero leakage" level seepage prevention capability
HDPE geomembranes have a permeability coefficient as low as 1.0 × 10⁻¹⁴ cm/s, hundreds of times lower than clay impermeable layers.
The greater the thickness, the higher the density; therefore, 1.5/2.0 mm provides more stable long-term barrier performance, a basic requirement for seepage prevention at the bottom of landfills.
Excellent chemical resistance (strong acids, strong alkalis, oils, salts)
Leachate contains highly corrosive substances, such as:
High ammonia nitrogen/oils/strong acids, strong alkalis/high-salt organic solvents
1.5mm / 2.0mm HDPE geomembrane exhibits complete inertness to these media and remains stable and non-degradable over the long term.
Service life of 50–100 years, with excellent aging resistance
Key reasons include:
Stable molecular chain structure of high-density polyethylene (HDPE)
Contains 2–3% carbon black for UV resistance
Formulation with antioxidants and heat stabilizers
Greater thickness results in slower photoaging and oxidation penetration
Ultra-high mechanical strength (tensile, tear, and puncture resistance)
Increased thickness leads to a significant improvement in mechanical properties, for example:
Tensile strength ≥ 27 MPa
Elongation at break ≥ 700%
Puncture resistance is far superior to that of thin films.
Excellent flexibility and settlement adaptability
Landfill sites experience significant uneven settlement.
HDPE membranes can stretch to 600%–800%, ensuring:
No tearing/No micro-cracks/Suitable for construction in complex terrains.
High welding strength (weld strength reaches 80-95% of the base metal)
Welded using a double-wedge hot-melt welding machine, with two weld seams and a central air cavity structure, allowing for:
Air pressure testing
Vacuum testing
Ultrasonic testing
Excellent temperature resistance (-70℃～+60℃ without brittleness or flow)
Maintains the following properties under extreme climate and temperature variations:
No brittleness/no softening/no deformation/no loss of mechanical properties
Excellent UV resistance (containing 2–3% carbon black)
Geomembranes are exposed for long periods in landfills, tailings ponds, and other similar projects.
Carbon black has the following characteristics:
Strong UV absorption capacity
Uniform dispersion
Significantly slows down photo-oxidation
The UV resistance of a 2.0mm thick film is 2–3 times longer than that of a 1.0mm thick film.
High resistance to stress cracking (ESCR)
Stress cracking is a key risk factor for membrane failure.
HDPE geomembranes possess the following characteristics:
High molecular weight raw materials/antioxidant system/thick plate structure/high elongation.
Lowest life-cycle cost (outstanding economic efficiency)
Although HDPE is a high-standard material, thick films offer the following advantages:
Longer service life/Lower failure rate/Extremely low maintenance costs/High success rate of construction and welding
Differences in Engineering Applications Between 2.0mm and 1.5mm
2.0mm Applicable Scenarios
Hazardous waste landfills
Main impermeable layer at the bottom of landfills
Tailorings ponds
High-temperature leachate treatment areas
1.5mm Applicable Scenarios
General municipal solid waste landfills
Slope cover layer
Temporary closure
Geomembranes possess ultra-low permeability coefficients, excellent chemical corrosion resistance, high mechanical strength, superior aging resistance, and stable welding quality, making them the most reliable, safest, and longest-lasting solution among all current seepage control materials.
With increasingly stringent environmental standards and more complex leachate compositions, using thinner or non-HDPE materials will lead to significant environmental risks and operational costs. Using 1.5mm/2.0mm HDPE geomembranes ensures landfills remain leak-free for decades after construction, truly achieving groundwater protection and ecological safety.
If you are selecting materials for landfills, tailings ponds, reservoirs, sewage treatment plants, or other permanent seepage control projects, 1.5mm/2.0mm HDPE geomembranes are always the most reliable and professional choice.
