Humanity generates vast quantities of industrial and domestic solid waste daily. Currently, landfills, incineration, composting, and pyrolysis and gasification are the primary methods for disposing of this waste. Landfills remain the most economical disposal method, especially in countries with available land. However, without appropriate anti-seepage measures, harmful components in the waste can easily be eroded by weathering, rain and snow leaching, and surface runoff, generating high-temperature and toxic leachate that can contaminate soil and groundwater. Therefore, it is crucial to properly implement an anti-seepage liner system at landfills.
1. What Is an Geomembrane Liner for Waste Containment?
Geomembrane Liner, also known as high-density polyethylene film, is currently the primary material used for engineering anti-seepage. HDPE (High Density Polyethylene) Liner has excellent corrosion resistance, electrical properties, moisture resistance, leakage resistance, and high tensile strength, making it ideal for applications such as wire and cable engineering, aquaculture, oil tanks, basements, artificial lakes, landfills, and solid waste landfills.
2.What Are Functions of Geomembrane Liner for Waste Containment?
Reduce the infiltration of rainwater and other external water into the landfill, thereby reducing leachate;
Control the emission of odor from the landfill and the organized release of combustible gases from the upper part of the landfill and collect them to achieve the purpose of pollution control and comprehensive utilization;
Control the reproduction and spread of pathogens and their carriers, mosquitoes and flies;
Prevent surface runoff from being polluted, avoid the spread of garbage and its direct contact with people and animals;
Prevent soil erosion;
Promote the stabilization of the landfill as soon as possible;
Provide a surface for greening and landscaping, provide soil for the growth of vegetation, and facilitate the reuse of landfill land.
3. What Are Advantages of Geomembrane Liner for Waste Containment?
Geomembrane Liner offers excellent anti-seepage properties, effectively preventing water from penetrating through the soil into the groundwater table. It is suitable for anti-seepage projects such as reservoirs, embankments, and river channels. Its strong resistance to chemical attack makes it inert and suitable for environments such as landfills and hazardous waste disposal.
Geomembrane Liner boasts high tensile and tensile strength, enabling long-term use in harsh environments and adapting to a variety of demanding projects. It withstands long-term use without losing its performance, exhibits excellent weather and aging resistance, and can withstand use at high or low temperatures without loss of performance. It also offers excellent heat and cold resistance.
Due to its excellent anti-seepage and leak-proof properties, Geomembrane Liner is widely used in various fields, including water conservancy, transportation, agriculture, and the environment. Geomembrane Liner has a low density, is lightweight, and exhibits excellent elongation, adapting to various deformations. It is relatively easy to install and maintain.
4. What Are Disadvantages of Geomembrane Liner for Waste Containment?
4.1 High Construction Quality Requirements
The anti-seepage effectiveness of geomembrane liner depends largely on construction quality. Improper construction, such as loose welding or uneven laying, can lead to geomembrane leakage. Therefore, strict quality control is essential during the construction process.
4.2 Susceptible to External Damage
Although geomembrane liner has a certain strength and toughness, it can still be damaged by long-term external forces such as water erosion and rock compression. Once damaged, its anti-seepage effectiveness will be seriously affected. Therefore, the protection and maintenance of the geomembrane must be strengthened during use.
4.3 Sensitive to Geological Conditions
The anti-seepage performance of geomembrane liner is limited by geological conditions. In areas with complex geological conditions, high soil moisture content, or uneven settlement, geomembranes may fail due to foundation deformation. Therefore, when selecting a geomembrane as an anti-seepage material, the impact of geological conditions must be fully considered.
4.4 Difficult to Repair
Once geomembrane liner is damaged, repair is difficult. Because it is generally laid underground or underwater, repair work requires a lot of manpower, material resources and time.
5. Main Considerations When Choosing the Best Geomembrane Liner for Waste Containment
The reliability of geomembrane liner is crucial for the intended functioning of liquid collection and leak detection systems and is crucial to the success of a landfill. The following factors can degrade the mechanical properties of geomembrane liner: 1. Tensile stress caused by deformation; 2. High temperature; 3. Oxidation; 4. Chemical attack; 5. Plastic volatilization.
Selecting the right geomembrane liner requires careful analysis of the waste composition, as it may interact differently with the geomembrane.
Municipal domestic waste is primarily inorganic, so geomembrane liner made of common materials can be used.
For waste containing organic solvents and corrosive chemicals, particularly those containing toxic substances and complex compositions, polyethylene geomembranes are commonly used. The higher the concentration and corrosiveness of the leachate, the higher the density of the polyethylene required. Therefore, HDPE (high-density polyethylene) and LDPE (low-density polyethylene) are the most widely used.
Regarding the required thickness of geomembrane liner, the US stipulates a minimum thickness of 1.5 mm (60 mils). Federal German regulations require a minimum HDPE geomembrane liner thickness of 2mm (80 mils), and only HDPE should be used. In actual projects, most projects use a thickness of 1.8mm to 2.5mm.
If a landfill uses a primary and secondary double-layer geomembrane, their materials and thickness should be identical. When landfills are thick, significant pressure is generated. Reports have shown that several geomembranes with thicknesses ranging from 0.75mm to 1.3mm were significantly damaged when placed in angular sand under a pressure of 400kPa. At the contact points, the membrane thickness was reduced to one-quarter of its original thickness. Membranes as thick as 1.25mm were also damaged when placed in gravel. Therefore, careful attention should be paid to the protection of the geomembrane liner. Using geotextiles as a protective layer is quite effective. Mechanical damage to the geomembrane liner must be prevented during production and construction, and a multi-level quality assurance system must be established.
6. Final Thoughts
Geomembrane liner effectively prevents leachate from entering the soil. A variety of single- and double-layer liner systems are currently used in waste containment. Typical liner cross-sections can be selected based on project conditions and economic viability. The selection of a geomembrane liner must meet requirements for thickness, mechanical properties, and chemical stability.
