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Supporting higher-value end uses for end-of-life tires offers clear benefits to landfill managers. Tires that are not diverted and end up in the landfill are among the most difficult wastes to manage. Because tires do not decompose and resist compaction, they can migrate or “float” within the waste mass. This can cause buried tires to re-emerge at the landfill surface over periods of years or even decades, potentially damaging landfill cover systems and requiring costly remediation.
Effective tire diversion reduces operational and regulatory risk, preserves valuable airspace, and helps prevent future collection pressures by supporting stable end-markets for recycled tire materials – all while improving infrastructure performance at a lower cost.
Leachate is the liquid that forms when rainwater or other liquids percolate through landfill waste, dissolving and carrying contaminants. It must be collected and managed to prevent contamination of surrounding soil, surface water, and groundwater.
A Leachate Collection System (LCS) consists of the layers and components immediately above the liner system that collect and transport leachate away from the landfill base. The purpose of the system is to rapidly drain leachate and maintain a low hydraulic head on the liner, which helps protect groundwater and preserve the integrity of the liner system. In this configuration, the liner prevents leakage into the surrounding environment, while the drainage layer and piping system ensure that leachate does not accumulate and create pressure on the liner.
Generally, the components of an LCS include:
TDA can serve as an effective drainage medium in the drainage layer of the LCS due to its high permeability and ability to perform under landfill loads. Its open structure allows leachate to move easily through the drainage layer, helping prevent excessive hydraulic head from developing on the liner system and ensuring that liquids flow toward collection pipes rather than accumulating at the base of the landfill.
Landfill drainage layers are subjected to significant compressive stresses as waste accumulates above them. Unlike conventional mineral aggregates, TDA exhibits elastic behaviour due to the rubber properties of tire material. This allows the particles to deform slightly under load and recover, helping maintain drainage pathways even after settlement. Studies show that although TDA compresses under landfill loads, it generally retains sufficient permeability to maintain effective drainage when properly designed.
Because TDA is compressible and compaction can continue over time under very high loads, caution is recommended when considering TDA for very deep landfills, particularly where final waste heights are expected to exceed 30 metres.
The lightweight nature of TDA also provides construction advantages. Because it weighs significantly less than gravel, trucks can transport larger volumes per load without exceeding weight limits, reducing deliveries and simplifying site logistics. The material is also easier to place and grade, improving installation efficiency.
Using TDA in landfill drainage systems can also provide environmental benefits. Replacing quarried aggregates with recycled tire material diverts scrap tires from disposal while reducing demand for natural aggregate resources. Some research also indicates that rubber materials can sorb certain organic compounds in leachate, which may slow the movement of some contaminants under certain conditions.
For many landfill projects in Alberta, TDA represents a high-performing, sustainable, and cost-effective drainage material for leachate collection systems.
Key Benefits:
The drainage media for a landfill cell can represent 5–15% of total project costs, meaning that even modest reductions in material price can significantly affect overall construction costs. Alberta’s Tire Recycling Program supports the recovery and processing of tire material, helping ensure a stable local supply of TDA that can often be provided at a lower cost than conventional aggregates. While cost savings are common, cost effectiveness should be evaluated on a site-specific basis.
Although TDA typically offers significant cost savings for municipal landfill expansion projects, it may be less cost-competitive at sites located very close to a gravel pit—especially if the pit is municipally owned. For most landfills in Alberta, TDA provides a high-performing, sustainable, and cost-effective material for leachate collection systems.
Download the TDA Cost Tool Spreadsheet to estimate potential project savings based on site-specific parameters.
TDA is widely used in Alberta landfills. Successful projects rely on close coordination between engineers, the registered tire processor, and site managers—each playing a key role in ensuring the highest-quality outcomes.
To better understand TDA’s long-term settlement behaviour under vertical load, ARMA commissioned testing using a custom-built 1-D Consolidometer to simulate real landfill conditions. The results confirmed that even with reduced pore space caused by compression, TDA would continue to perform effectively as a leachate collection layer under the load conditions in most Alberta landfills.
Effective drainage is essential to control leachate buildup above the liner, which can be affected by the permeability of the leachate blanket, effective drainage to a collection point, and subsequent removal. Alberta regulations specify allowable leachate levels, making permeability a critical design factor.
ARMA commissioned permeability testing of TDA using a purpose-built 2-D permeameter tailored to its unique properties. The equipment applied high vertical loads simulating waste thicknesses up to 50 metres. The results indicated that even when compressed under a high vertical load, TDA maintained a permeability well above the target value of 10⁻² m/s. These research findings align with results in the field and confirm that TDA provides strong, consistent drainage performance under real-world conditions
Landfill liners play a critical role in containing and controlling leachate, protecting soil and groundwater, and ensuring the landfill operates in compliance with regulatory standards. Geomembranes are increasingly being used in landfill lining systems due to their exceptional ability to contain liquids and protect the environment, but to maintain a geomembrane’s performance, it must be protected from physical damage.
ARMA commissioned a study comparing TDA and gravel under a range of conditions, including winter scenarios with frozen TDA, involving different combinations of geomembranes, geotextile protective fabrics, and other material types. The study design allowed researchers to assess how the orientation and surface features of both TDA and gravel affect liner protection.
The findings indicated that while both TDA and gravel have the potential to increase the risk of liner damage, this can be managed by the use of appropriate protective layers such as geotextiles Gravel edges can create concentrated stress on the liner, and protruding wires from TDA particles have the potential to cause punctures if not properly separated. The study highlighted the importance of using appropriate protective layers—such as geotextiles—between geomembranes and any structural materials.
With appropriate design and installation practices, engineers can confidently incorporate TDA while protecting geomembrane systems and reducing overall project costs.
When organic waste decomposes in landfill, it produces methane, a powerful greenhouse gas (GHG). If released to the atmosphere, methane contributes significantly to climate change. Landfill gas collection systems capture this methane and either flare it or use it as an energy source. When methane is combusted, it is converted to carbon dioxide, which has a lower global warming potential than methane.
Landfill gas (LFG) collection systems are designed to capture gases generated within the waste mass and convey them to a central location for treatment, flaring, or energy recovery. Gas is typically collected using one or more of the following components:
Perforated piping is often installed within these permeable layers to increase gas collection efficiency. Systems may operate passively, where gases move through the permeable media to vents, or actively, where a vacuum system extracts landfill gas and conveys it to a flare or energy recovery facility. Captured landfill gas can also be used as a renewable energy source. Many landfill operators use it to generate electricity or heat, producing energy that can be used on-site or exported to the electrical grid.
Due to its high permeability and durability, TDA can serve as an alternative to conventional aggregates in many landfill gas collection applications.
TDA can be used in applications such as gas extraction blankets, gas collection trenches, and vertical gas extraction wells. When used as a gas extraction blanket beneath a final cover system, the TDA layer is typically covered by less than 1 m (3.3 ft) of soil. Under these conditions, the vertical stress on the layer generally remains below 20 kPa (400 psf), allowing the material to maintain high permeability and effective gas flow.
Key Benefits:
In addition to performance advantages, TDA can also provide construction and cost benefits. Its lower unit weight allows larger volumes to be transported per truckload, which can reduce hauling and installation costs, particularly when locally sourced.
When incorporated into landfill gas collection systems, TDA can provide reliable gas flow pathways while supporting efficient gas capture and energy recovery, helping landfill operators improve overall system performance and reduce greenhouse gas emissions.
TDA is a cost-effective, environmentally friendly alternative to traditional drainage materials used in landfill leachate collection systems. Through Alberta’s Tire Recycling Program, ARMA covers 100% of the production cost and partially subsidizes delivery to landfill sites.
This offers municipalities, First Nations and Métis Settlements, waste authorities, and commissions that order TDA for future landfill cells (up to three years before the actual cell is built) significant cost savings compared to conventional aggregate.
To inquire about using TDA for your next landfill cell, please call our Tire Program Administrator at 1.888.999.8762 or download the Tire-Derived Aggregate (TDA) for Landfill Leachate Collection Systems Grant Application Form.
*Alberta Recycling makes no warranty, express or implied, and assumes no liability for the information provided in this website. References to individual businesses and their commercial products do not constitute an endorsement by Alberta Recycling. The information contained in this website is not complete, and is provided as a convenience to our website visitors and for informational purposes only.
