How our landfills work

Calgary’s landfills are highly engineered and sophisticated facilities that carefully manage our wastes for minimal impact to the environment.

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About our landfills

Today's modern landfills are very different than the open dumping grounds of decades before.  

The City of Calgary operates three active Waste Management Facilities (WMF) at the East Calgary, Spyhill and Shepard areas. These three sites host The City’s landfills and other important waste infrastructure and disposal services. Additionally, The City owns and maintains four closed landfill sites.

Calgary's priority is to continue extending the life of our landfills. Landfills are complex engineered facilities that need to be maintained whether they are still open or closed.

Trying to make the most of the landfill space we currently have is financially and environmentally prudent. As of 2023, the three City landfills have close to 40 years of capacity remaining.

What happens to our garbage

Waste collected at a City landfill is disposed of in landfill cells – engineered areas of the landfills comprised of an excavation in which waste in enclosed.

Because of harmful greenhouse gas emissions like methane and generation of leachate, the structure of a landfill cell is designed to protect the surrounding environment from potentially adverse effects such as capturing landfill gases and preventing any discharges from leaking to other locations.

See how garbage is stored at the landfill

There are multiple steps when it comes to handling garbage inside a landfill cell. Click on the steps below to learn more at each stage.

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Step 1 When bringing garbage to the landfill

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All vehicles will go through a scalehouse where they are weighed on the way in and on the way out. The vehicle is directed to the working face, the area where the garbage load will be emptied out.

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Step 2 Compacting garbage

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A dozer will then push and spread the garbage in a specific direction. From there, the compactor will drive on top of the garbage to pack down the materials and make room for more garbage. Layers of garbage are tightly compacted to reduce the volume - both to save space and to reduce the amount of oxygen in the landfill to make it as inert as possible. 

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Step 3 Daily cover

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At the end of each day, a daily cover is laid on top of the garbage materials. This layer of soil is laid down at the end of each day to prevent the wind from blowing garbage away and to help contain any odours. Other layers of soil applied across the working face include a fire break layer and intermediate cover layer. Both layers separate waste into confined compartments to minimize fire hazard, leachate generation and landfill gas emissions.

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Step 4 Multi-layered liner system

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The liner system is made up of multiple layers to prevent leachate and gases from migrating into the groundwater and surrounding soils. The four layers include: a compacted clay liner (CCL), a high density polyethylene (HDPE) geomembrane, a geocomposite layer, and a drainage layer (sand or gravel) on top.

Working together, these layers act as a barrier for the landfill cell.

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Step 5 Leachate collection system

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When water encounters waste in the landfill cell, it undergoes chemical changes and becomes leachate that requires treatment. A collection system gathers and removes the leachate from the landfill cell.

As the leachate migrates through the garbage towards the lowest point in the liner, it is collected through a system of drainage pipes at the bottom of the cell. Perforated holes in the pipes collect the leachate and takes it to a leachate sump. A leachate tanker truck will pump the leachate out until the sumps are empty. The leachate is then transported to The City’s wastewater treatment plants for disposal and treatment.

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Step 6 Groundwater monitoring wells

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Groundwater is the water beneath the surface of the ground. It is found in underground spaces between particles of rock and soil and consists largely of surface water and precipitation that has seeped into the soil.

To ensure that no leachate or other contaminates are affecting the groundwater, all City landfills evaluate the groundwater quality within the landfill boundaries. Groundwater monitoring wells are placed close to the edge of the landfill cell to go deep into the ground to the water table.

Groundwater sampling is completed twice a year in the spring and fall.

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Step 7 Landfill gas system

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Landfill gas is another byproduct that needs to be handled carefully. It’s produced by the natural breakdown of organic waste in a landfill and includes methane and carbon dioxide, as well as small amounts of other compounds such as hydrogen sulfide.

The landfill gas system helps to capture these gases to prevent them seeping further underground or releasing into the atmosphere. Like the leachate system, a series of pipes pulls the landfill gases into a collection system and takes it to a separate processing building at the landfill. The collected gas is flared or burned reducing the potent methane gases into a less harmful carbon dioxide to lower the landfill’s greenhouse gas emissions.

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Step 8 Closed landfill cell

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When a landfill cell has reached capacity, it is “capped off” to reduce infiltration of rainwater into waste, minimize generation of leachate and landfill gases, and prevent greenhouse gas emissions into the atmosphere.

This cap consists of multiple layers of soil including a final clay barrier and a “cap” or final layer seeded with native grasses. 

 

Why we need to recycle and compost to help our landfills

People often think that material buried in a landfill will break down eventually.

But that’s not true – as materials get buried in the landfill, the lack of oxygen results in items like food scraps breaking down very slowly in anaerobic conditions.

This results in:

  • Landfill gases such as carbon dioxide and methane. Methane is a powerful greenhouse gas that’s 25 times more potent than carbon dioxide.
  • Leachate is a contaminated liquid that is a result of water coming into contact with garbage. As liquids in the waste and precipitation runs through the buried garbage, it will “leach” contaminates along the way. Leachate eventually needs to be treated.

Pictured here are items from the 1970s, uncovered at a Calgary landfill decades later. Can you read the date on this newspaper?

These 1970s grass clippings still look the same as when they were first thrown in the garbage.

As you can see with these chicken bones, food scraps do not break down in the landfill.

All of these items take up valuable landfill space and create harmful emissions.

This is why it is important to reduce, reuse, recycle, compost and separate your materials properly at home so only unusable, end-of-life garbage ends up in the landfill.

What happens when a landfill is full

When a landfill closes, it is still monitored to see how the garbage is decomposing and how this could impact the surrounding environment. In Calgary, you will often see rolling hills around the landfill sites – they are closed landfill cells filled with garbage!

Studies show that the process of decomposition in a landfill is extremely slow. In fact, some wastes such as glass, metals and plastics do not break down at all.

You may be surprised to see what an old landfill has now been turned into.

  • Rugby fields

    Former Ogden landfill site

    Opened: 1968

    Closed: 1997

  • City park

    Former Blackfoot landfill site

    Opened: 1968

    Closed: 1972

  • Softball fields

    Former Springbank landfill site

    Opened: 1959

    Closed: 1968

  • Zoo Parking lot

    Former Nose Creek landfill site

    Opened: 1948

    Closed: 1969

Environmental requirements of City landfills

The City of Calgary landfills are regulated by the Province through the Environmental Protection and Enhancement Act (EPEA). All three active sites are Class II non-hazardous waste landfills. The Province grants an Operating Approval which specifies all of the requirements that must be met to ensure the landfill is operating safely.

Landfill monitoring

Each City landfill is monitored to meet environmental performance objectives required through legislation and regulatory guidance.

This includes monitoring of:

  • Groundwater quality
  • Surface water quality (run-ons and run-offs)
  • Landfill gas (above and below ground)
  • Leachate
  • Landfill operations

Under provincial regulations, residential development must be located at least 300 metres from a landfill property boundary.

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