An Alternative to Dumping
Landfills are the most common form of waste disposal, and an important part of waste management systems. A landfill is a waste disposal system that involves burying large amounts of trash in designated areas, and covering it with layers of dirt, soil, woodchips, temporary blankets, or other materials. As more trash is added, the height of the landfill gradually rises.
Landfills as an Early Form of Environmentalism
Landfills were originally created as a progressive alternative to worse waste disposal habits. Before landfill systems were in place, trash of all kinds was commonly disposed of in the oceans, streets, or anywhere that was convenient, including open dumps that allowed leachate, a liquid formed by decomposing waste, to soak into the surrounding ground and water, attracted pests, emitted odors, and created fire hazards. The U.S. Supreme Court banned ocean dumping in 1934, and the first U.S. landfill appeared in Fresno, California, in 1937.
Today’s landfills are government-regulated, and address leachate and explosive gas concerns among other things. Many states require plans be in place for the closing of a landfill, no matter how far in the future it might be. Closed landfills still have to be monitored regularly, and can later be reused as parks and other recreation areas.
How Waste is Stored
Waste is delivered to land areas that have been designated as landfills. In a typical modern landfill, this land is lined with a layer of clay and protective plastic to prevent toxins like leachate from leaking into the ground or ground water.
Upon arrival to the landfill, the trash is either spread out manually, or compacted into smaller bundles. Dirt or other materials like woodchips are used to cover the trash in successive layers, protecting it from wind, cutting odors and reducing pests, until the landfill area gradually reaches its capacity. This amount is determined via topographical surveys and weight estimates.
Trash is not dumped randomly but is placed in pre-determined sections of the landfill, or cells. Cells are filled one by one until they are at capacity — then a new cell is opened for dumping. Each day, the contents of a cell are compacted and covered, while leachate from the trash is drained through the bottom of the cell and collected for treatment. Gas emissions from the waste can also be captured and monitored.
If a landfill is not properly designed or managed, methane can become an issue. Various trash materials may emit methane (CH4) into the atmosphere. In a landfill, common organic waste like wood, paper, food, and yard trimmings, materials which could decompose aerobically elsewhere, are deprived of oxygen and decompose anaerobically, potentially emitting methane into the atmosphere. Methane is a powerful greenhouse gas. This gas is known to hang in the atmosphere and interfere with the sun’s radiation as it bounces off the Earth. In time, an over-accumulation of greenhouse gases can contribute to raising the surface temperature of the planet. However, some landfills have mechanisms for capturing these gas emissions — and some of those can even acquire energy through these gas emissions.
If landfills are not properly managed, they can pose significant environmental risks. For example, if a liner leaks, there is risk of leachate contamination in the surrounding soil and ground water. Landfills are often located in more remote areas — meaning waste must be hauled long distances, which generates its own emissions.
Loss of Recyclables
Many otherwise recyclable materials are disposed of in landfills. With proper processing, these materials might have commercial and practical value for the economy. However, once dumped in a landfill, this potential value may be lost, and new costs to the environment will be incurred to replace them.
These potentially recyclable materials also take up valuable landfill space. For example, as much as 50% of all landfill space is taken up by paper; 3 cubic feet of landfill space would be saved for every 1 ton of newspaper recycled.