Fact Filled Tuesday: Landfills

What is a landfill?

A landfill is a large area of land or an excavated site that is specifically designed and built to receive wastes. Today, about 56 percent of our country’s trash is disposed of in landfills (EPA, 2003). Items such as appliances, newspapers, books, magazines, plastic containers, packaging, food scraps, yard trimmings, and other wastes from residential, commercial, and some industrial sources can be disposed of in municipal solid waste landfills.

In the past, garbage was collected in open dumps. These uncovered and unlined sites allowed leachate, a liquid formed by decomposing waste, to soak into the soil and ground water.

Wait, What’s leachate?

A leachate is any liquid that, in the course of passing through matter, extracts soluble or suspended solids, or any other component of the material through which it has passed.

Open dumps also attracted rodents and insects, emitted odors, and created fire hazards.

Most of these small and unsanitary dumps have been replaced by large, modern facilities that are designed, operated, and monitored according to strict federal and state regulations.

Today’s landfills eliminate the harmful and undesirable characteristics of dumps to help protect public health and the environment.

In 2001, more than 1 million tons of hazardous waste was disposed of in landfills or surface impoundments. Hazardous waste is toxic, ignitable, corrosive, or reactive, or generated from certain industries or manufacturing processes

How does a landfill work?

A typical modern landfill is lined with a layer of clay and protective plastic to prevent the waste and leachate from leaking into the ground or ground water. The lined unit is then divided into disposal cells.

After a day’s activity, the garbage is compacted and covered with a layer of soil to minimize odor, pests, and wind disturbances

The leachate is sent to a leachate recovery facility to be treated. Methane gas, carbon dioxide, and other gases produced by the decomposing waste are monitored and collected to reduce their effects on air quality.

Are there any benefits to landfills?

In addition to providing a cost-effective, safe method to dispose of ever-increasing amounts of trash, landfills often provide other services to the community. For example, some landfills collect methane, a gas created by decomposing garbage that can contribute to global climate change , and convert it into an energy source. In addition, after a landfill is capped and a certain amount of time has passed, the land might be reused for parks, ski slopes, golf courses, and other recreation areas.

Are there any challenges to landfills?

Landfills can pose other problems if not properly designed or managed. If a liner leaks, for example, the underlying soil and ground water can become contaminated.

What are the emerging trends with landfills?

Increased waste generation requires landfill operators and managers to constantly evaluate and improve current disposal methods. One strategy to speed the rate of decomposition of landfill waste is to recirculate the collected leachate by pouring it over the cells and allowing it to filter through the rotting garbage.

A new trend that is gaining attention is landfill reclamation, in which old cells are excavated to recover recyclable items.


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