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. 

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.

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.

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.

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.

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.

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.