Sanitary Landfills: How are they Made?

Landfills:

Landfills are made and operated by layering waste in a large hole. The deepest spots can be up to 500 feet into the ground, like the Puente Hills Landfill, where a third of Los Angeles County’s garbage is sent. As materials decompose, landfill gas experts continuously monitor groundwater to detect any leakage. They are constructed and made up of a 4 layer system .

Layer 1: The Liner System

The bottom of a modern landfill is typically lined with compacted clay dense enough to prevent liquids from penetrating it. On top of the clay, landfill engineers install a liner made of high-density plastic for added protection.

Layer 2: The Drainage System

Some waste produces liquid as it decomposes. As rain and snow filter through a landfill, it can carry other contaminants to the bottom. Perforated pipes are installed on top of the liner to collect these liquids—known as leachate—and funnel them to treatment facilities, either onsite or at wastewater treatment plants.

Layer 3: The Gas Collection System

Waste naturally produces methane as it decomposes and when methane is released into the atmosphere, it contributes to global warming. But methane is also the main component of natural gas. Modern landfills work to turn methane into power using gas extraction wells that pipe it to treatment areas and then to plants that will turn it into electricity or other forms of energy.

Layer 4: The Trash Itself

In the main area of the landfill, trash is delivered and then compacted to take up less room. Every day, the new trash is covered with a layer of dirt which helps contain odors and deter pests.