What is landfill capping?
Landfill capping is a process of placing a protective cover over a landfill once it has reached the end of its operational life. Alternate terms used for landfill capping is closure capping or final capping. The main purpose of landfill capping is to set apart and contain the waste within the landfill to prevent environmental pollution and risk . Precisely it is a process of establishing a shield between the waste materials and the surroundings to control the release of gases, contaminated liquid and other potential hazards.
How is landfill capping done?
- Site preparation- It is the process of clearing the surface materials, levelling and compressing the soil to assure stability. It is also done to install the required infrastructure before the further installations.
- Installation of capping layers- There are four types of layer that are installed during this process ,
These layers are:- Vegetative layer- The Covering layer consists of mixtures of soil and vegetation where grass or any other kind of plants may be used and the finished project gives a green-colored surface cover. The main function of the vegetative layer with top cover is to protect from soil erosion, reduce rain surface runoff, and improve aesthetic appearance. Roots of vegetation also help in stabilization.
- Barrier layer- This barrier layer of geomembranes or geosynthetic clay liners is intended to prevent infiltrating water from entering the landfill, controlling movement of gases, particularly methane, and seeping into the atmosphere. This can be considered the most vital layer in minimizing the risks of contaminating groundwater and off-gassing.
- Drainage layer- Gravel, sand, or a geosynthetic drainage composite generally consists of this layer. It promotes the flow of water away from the barrier layer as a sort of prevention method so that it pools water or ponds on the surface less and thereby reduces the accumulation of leachate in the landfill. Ensuring proper drainage will continue to protect the barrier layer’s integrity and further prevent erosion.
- Protection layer- Protection is always laid on top of the barrier layer to ensure no form of damage is brought about in the process of construction or the maintenance practices that may follow. It could be made of soils, geotextiles, or other protecting means. The protection layer ensures that the barrier layer is kept safe, wholly allowing the efficacy of the entire capping system.
- Final Cover system- During this step the topsoil is established with plants to secure a stable and environment friendly final cover.
What are the main objectives of landfill capping?
Objectives of landfill capping are-
- Preventing water infiltration: Landfills contain a variety of waste materials, both organic and inorganic matters, some of which can be harmful if they get into the environment. When rainwater infiltrates a landfill, it seeps through the waste layers, picking up contaminants and carrying them into the surrounding soil and water.
- Controlling gas emissions: When organic waste is decomposed in a landfill, it produces gases like methane and carbon dioxide. These gases can get collected within the landfill and can get through the soil into the outer atmosphere.
What are the benefits of Landfill Capping? - Environmental protection: The cap installed prevents the release of leachate and the prevention of oxygen does not allow methane to pass in the environment which further prevents environmental degradation.
- Land reclamation: These sites can be reused for various purposes such as setting up solar farms and green spaces or even for commercial and residential use. This reclaiming can put the land to good use.
- Long- term stability: The capping layers provide stability and protection against erosion. Properly capped landfills are safer and more visually appealing compared to uncovered or poorly managed sites.
Why is methane control important in landfill capping?
It is important to control methane in landfill capping because, methane is a powerful gas that results in climate change. Whenever an organic waste is decomposed in landfills, it produces methane gas. If methane gets into the air, it can trap heat in the atmosphere, which will eventually lead to global warming. By trapping methane we can –
- Reduce the amount of methane released into the atmosphere.
- Decrease the landfill’s impact on climate change.
- Reduces potential methane secretion for energy with the help of processes like landfill gas-to-energy projects.
Great examples of landfill capping from Strata Global
Some projects that Strata Global has undertaken have realised landfill capping with rather unconventional and novel solutions that showcase its competencies in the management of environmental impacts.
The Project Embalses El Risado, Villena – Alicante, Spain, was for efficient landfill capping by using advanced techniques. The capping system included StrataGrid™ for effective rainwater drainage and gas collection, which is very vital in less leachate production and control of moisture infiltration amongst others. There was a design to have multiple layers; the drainage layer to divert the excess water, the gas collection layer for the collection of emission gases, protective cover for slope stabilisation. This holistic capping approach has ensured that structural integrity at the landfill was attained and met environmental regulations, thereby being in line with sustainability.
Another important project was at Ghazipur, New Delhi, India; it was for the erosion control of the landfill encasement slopes. The work is carried out with the use of the StrataGrid™ and StrataWeb® systems for provision of a highly durable capping system, which stabilises the slopes of the encasement against erosion. It provides a lintel effect with geogrid materials that stack up for stabilisation of the soil from runoffs, thus protecting the fill from environmental damages. The capping design provided security and functionality to the landfill by mitigating risks due to erosion, protection of surroundings, and communities with ecosystems.
Landfill capping is a great step towards sustainability . Being a part of this environment it’s also our duty to protect it as well, and landfill capping exactly supports that . Landfill capping turns waste into beautiful and productive land which can be used for various purposes. It’s important to put development with sustainability to preserve nature and leave an example for our future generations to be the same.
For innovative solutions in landfill capping, Strata Global provides advanced geosynthetic products tailored to ensure long-term stability and environmental protection. Contact Strata Global today to get started with efficient landfill management and sustainable land use. Transform your waste management projects with proven expertise and reliable products.