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How Long Is the Average Landfill Open?

Unlike popular images of pits in the ground, landfills are actually highly technological sites for the disposal and treatment of human produced waste. While the length of a landfill's use as a dump site varies according to the initially authorized permit for the facility, another way to consider how long a landfill is open is to consider its various stages of operation. When taking into account liner construction, active dumping, landfill capping and land reclamation, the average landfill may be in operation for more than eighty years. Knowing these stages of a landfill's operation is important for understanding the waste process and planning for future use of landfill sites.

Liner Phase
- A landfill officially opens after the bottom half of the landfill liner has been constructed. A landfill liner typically consists of a thick layer of compact clay, a layer of synthetic protective material, a layer of sand and gravel which holds the leachate -- liquid that passes through the waste -- collection system and a protective layer of soil that protects the collection system from puncture. A restricted layer of waste, such as contaminated soil, may be used first to create an extra barrier between household trash and the liner system.
Primary Dumping
- Once a liner has been constructed a landfill enters it primary dumping phase. The length of the primary dumping phase varies according to the original permit and agreement between the landfill operating company and the state and local government. The Puente Hills landfill outside of Los Angeles is the largest in the Unites States at over 490 feet in height and it opened in 1957. This landfill is set to close in October of 2013, giving it a fifty-six year operating age.
Capping Phase
- When a section of landfill meets it permitted height limit it enters a phase of capping. In preparation for capping, landfill gas reclamation systems are installed, a synthetic liner covers the top layer of the landfill and a fresh layer of soil cover is added. According the EPA, operating companies must manage a landfill site's leachate and gas byproducts for thirty years after the capping and closure of a landfill. This adds time to the length of a landfill, and money for capping must be reserved by the operating company throughout the years of regular operation.
Reclamation Phase
- The final phase of a landfill is reclamation of the land for purposes other than waste disposal. This marks the official end of a landfill's operation as a waste site. Many landfills are turned into parks or nature reserves, such as the Tifft Nature Preserve in Buffalo, New York or the Trinity River Audubon Center in Dallas, Texas, which is a sustainability project that uses the former landfill property to collect rainwater for agricultural irrigation. The reclamation phase is often planned during the operation of an active landfill because it is an important step in officially ending the life of a landfill.

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