With urbanization and population growth, landfills are indispensable facilities for handling urban waste today and waste management is very important. Landfills are used in the waste management process.
As one of the most important materials in landfills, geomembrane plays a key anti-penetration role. Generally speaking, geomembranes are located at the bottom of landfills, playing an isolation role, preventing waste from leaking at the bottom from contaminating groundwater, and reducing the negative impact on the ecosystem.
Geomembrane is a waterproof barrier material based on polymers. It is divided into low-density polyethylene (LDPE) geomembrane and high-density polyethylene (HDPE) geomembrane. Linear low-density polyethylene (LLDPE) film combines the advantages of high-density polyethylene and low-density polyethylene and has excellent tear resistance.
Geomembrane physical properties
a. HDPE membrane has excellent physical properties, including high strength, high tension, and abrasion resistance, allowing it to withstand the pressure and load of a landfill environment.
b. The excellent performance of tensile strength makes HDPE membranes widely used in various geotechnical projects (landfills, tailings storage sites, channel anti-seepage, dam anti-seepage subway engineering, etc.).
Geomembrane chemical properties
a. HDPE material has very high chemical stability and strong resistance to chemicals and biodegradable substances.
b. This chemical stability is a key factor in ensuring the geomembrane’s long-term resistance to corrosion and penetration in a landfill environment.
The role of geomembrane in landfills
1. Geomembrane can reduce the penetration of rainwater and other external water into the garbage dump, thereby achieving the purpose of reducing garbage leachate.
2. Control the odor emission of the landfill and the organized release and collection of combustible gases from the upper part of the landfill to achieve the purpose of pollution control and comprehensive use.
3. Inhibit the reproduction and spread of pathogenic bacteria and mosquitoes and flies.
4. Prevent surface runoff from being polluted, and avoid the spread of garbage and direct contact with people and animals.
5. Prevent soil erosion.
6. Promote the stabilization of garbage piles as soon as possible.
7. Provide a surface that can be landscaped, provide soil for the growth of vegetation, and ease the reuse of landfills.
The role of geomembrane in landfills is reflected in its excellent anti-penetration performance and environmental protection functions. By forming a reliable isolation layer, geomembranes prevent bottom seepage water from contaminating groundwater and the surrounding environment. This is critical to maintaining water quality, reducing soil and water contamination, and ensuring compliance in landfill operations.
The Importance of Geomembranes in Landfills
If geomembrane materials are not used in landfills, the following problems may result:
1. Groundwater pollution: Harmful substances in garbage may penetrate groundwater, causing groundwater pollution. This poses a potential threat to drinking water sources and ecosystems in surrounding areas.
2. Soil pollution: The waste in the garbage seeps into the soil, which may cause soil pollution and affect the growth of vegetation and the sustainability of the soil.
3. Diffusion of harmful gases: Without a protective layer, organic matter in landfilled garbage may decompose to produce harmful gases, such as methane and hydrogen sulfide. These gases may diffuse into the surrounding environment, affecting air quality and residents’ health.
4. Diffusion of flying materials: Uncovered garbage is blown away by the wind, causing environmental pollution in surrounding areas, and may have adverse effects on traffic, communities, and farmland.
5. Increased fire risk: Without effective control measures, garbage in landfills may be more likely to catch fire, increasing the risk of fire and posing a threat to the environment and personnel safety.
6. Negative impact on the landscape: The lack of a protective layer may result in a poor appearance of the landfill and hurt the surrounding landscape and community image.
In summary, the application of geomembranes in landfills is an important measure to prevent environmental pollution, protect water resources, maintain air quality, and ensure public safety. If geomembrane materials are not used, adverse impacts on the environment and human health will be increased. Thus, it is necessary to use appropriate protective measures during the landfill process.
How to construct and install geomembranes in landfills?
The construction and installation of geomembranes in landfills is usually a precise and systematic process to ensure that the geomembrane can isolate garbage and groundwater and prevent leakage. The following are general geomembrane construction and installation steps:
1. Site preparation and leveling: Clean and level the bottom of the landfill to ensure a flat surface and cut sharp objects and large particles to prevent damage to the geomembrane. Remove any obstructions that may affect geomembrane construction.
2. Laying of base layer: Lay a layer of geotextile or similar base material to protect the geomembrane from wear and damage on the bottom surface.
3. Unfolding the geomembrane: Unroll the geomembrane from the reel to ensure it is completely laid on the site. Avoid stepping on the geomembrane at the construction site to prevent damage.
4. Seam treatment: Treat the seams between geomembranes, usually through hot melting, extrusion or chemical welding to ensure that the seams are firm and leak-free. Seam locations are inspected and tested to ensure the continuity of the geomembrane.
5. Edge treatment: Fix the edge of the geomembrane to the edge of the site, usually by burying soil, fixing nails, or other fixing means to prevent the geomembrane from being blown or moved by the wind.
6. Equipment and pipeline crossing processing: Perform equipment and pipeline crossing processing at the required locations. This may include cutting over the geomembrane and using appropriate sealing materials, ensuring that the performance of the geomembrane is not affected.
7. Further covering layer: Cover the geomembrane with a layer and continue to lay geotextile or other protective layers to prevent damage to the geomembrane from sunlight, oxidation, and other environmental factors.
8. Inspection and testing: Inspect the entire geomembrane system to ensure there are no breaks, defects, or leakage points. Anti-penetration performance testing is performed to verify the effectiveness of the geomembrane.
9. Records and documents: Record the geomembrane installation process, including joint processing, equipment crossing, and other special circumstances. Archive relevant documentation for future monitoring, maintenance, and verification.
The above steps need to be carried out under suitable environmental conditions and in strict compliance with relevant design specifications and regulations. Professional geotechnical engineers and technicians are usually responsible for the supervision and management of construction to ensure the quality and performance of geomembrane installation.
In current landfill projects, high-density polyethylene (HDPE) membranes are used as geomembrane materials and have become the first choice for bottom isolation layers. Its excellent anti-permeability properties, chemical stability, and mechanical strength provide strong support for the sustainability and environmental protection of landfills. HDPE membrane not only isolates garbage leakage and reduces the risk of groundwater contamination, but also meets the requirements of modern environmental regulations and engineering standards.
But, with the continuous development of technology and higher requirements for environmental sustainability, more innovative geomembrane materials may emerge in the future. New materials may pursue higher eco-friendliness, better degradability, and properties that are more adaptable to different geological and climatic conditions. Thus, professionals in the field of geotechnical engineering will continue to strive for new materials and more advanced construction technologies to promote the continuous progress of landfill engineering environmental protection and sustainability.
In the future development of geomembrane technology, we look forward to seeing more innovations to ensure that the geomembrane system at the bottom of the landfill plays an even better role in protecting the environment and maintaining the quality of human life. By exploring new materials and improving construction techniques, we are better able to meet the challenges of waste management and create a healthier, more sustainable environment for the future.