A landfill site (also known as tip, dump or rubbish dump and historically as a midden) is a site for the disposal of waste materials by burial and is the oldest form of waste treatment. Historically, landfills have been the most common methods of organized waste disposaland remain so in many places around the world.
When a landfill has reached its capacity, it is required to close consistent with U.S. EPA "final cap" environmental requirements. A final layer of clay and dirt "cap" the landfill. It is then is re-landscaped according to closure plans drawn up in accordance with the community. This process is planned many years in advance.
A typical landfill is divided into a series of sections called "cells." Solid waste is placed on what is called a "working face," which is a portion of a landfill cell that is currently available to accept this material. Only limited sites in a landfill are exposed at any given time to minimize exposure of the landfill's contents to environmental elements like wind and rain. Because a landfill is filled so systematically, landfill operators may be able to pinpoint where a specific load of garbage was deposited days, weeks, or even months afterward.
After all, landfill trash stays around for a very long time. That's because landfills are designed to bury trash, not break it down. They are airtight, so oxygen and moisture do not break down the trash the same way they would in a dump. Because trash is protected from decomposing, landfills have been known to keep newspapers intact and easily readable up to 40 years later. When a landfill closes, the site and its groundwater must be monitored for up to 30 years!
Large amounts of e-waste have been sent to countries such as China, India and Kenya, where lower environmental standards and working conditions make processing e-waste more profitable. Around 80 % of the e-waste in the U.S. is exported to Asia.
E-waste represents 2% of America's trash in landfills, but it equals 70% of overall toxic waste. The extreme amount of lead in electronics alone causes damage in the central and peripheral nervous systems, the blood and the kidneys.
For example, a landfill cannot be placed near a wetland, fault or floodplain. Landfills are lined with at least 2 feet of compacted clay soil covered by a flexible membrane. A leachate collection and removal system, installed on top of the membrane, collects any liquids that may leach out of materials in the landfill. Scientists periodically take samples from nearby groundwater to ensure that all of the systems are working and that there is no contamination.
Landfill space costs money for state and local governments, which do not receive a monetary return on this investment. Recycling, on the other hand, produces income that not only offsets the cost of establishing recycling facilities but also generates significant income through tax revenues for local, state and federal governments. The EPA reports that recycling enterprises produce an estimated $236 billion in annual revenues.
Public parks don’t tend to be cash cows, not unless they get advertising or become, well, private. But the park that sits on top of the old Fresh Kills Landfill on Staten Island is different. It won’t initially open for at least another three years, and its full opening won’t be until around 2030. But it’s already making the City of New York a cool $12 million a year.
A recent study by the U.S. Environmental Protection Agency concluded that incinerating a ton of trash emits at least 35% less greenhouse gas and yields 10 times more electricity than burying it and capturing the methane. So why does America still seem so in love with landfill?
The environmental impact of landfill sites varies depending on how well they're managed and resourced. However, typical problems include the contamination of soil and groundwater from toxic residues; the release of methane, a greenhouse gas produced during the decaying process that is more potent than carbon dioxide; and disease-carrying pests.
Currently more than 82% of discarded electronics end up in the trash, even though the hazardous chemicals in them them could leach out of landfills into groundwater and streams. Burning the plastics in electronics can emit dioxin. Out of 3.19 tons of e-waste generated in the U.S. in 2009, 2.59 million tons went into landfills and incinerators (82.3%) and only 600,000 tons (17.7%) was recovered for recycling. However, a significant amount of that 17.7% was exported.
Houston-based Waste Management ( WMI - news - people ) is the king of the hill when it comes to managing the nation's biggest landfills. It operates five of the top 10 and owns three of those outright. As a result there's no company that burns more landfill gas than WM: 100 plants generating 500 megawatts, enough for 400,000 homes.
Which community can boast to have the No. 1 dump? That honor goes to Las Vegas: The Apex Regional Landfill north of Sin City currently receives on the order of 9,000 tons a day. Back in the boom year of 2007, it was getting more like 15,000 tons a day. At 2,200 acres, it has enough room to keep pulling in waste at this pace for 200 years.
“In theory, turning a landfill into a park transforms a noxious liability into an attractive asset,” said Peter Harnik, Michael Taylor and Ben Welle in “From Dumps to Destinations: The Conversion of Landfills” to Parks, a case study in the December 2006 issue of Landscape Architecture Magazine. “As a “sustainable’ recycling of urban assets, in many cases it works beautifully.”
The landfill, known as Jardim Gramacho or Gramacho Gardens, is piled almost 300 feet high across 14 million square feet -- the equivalent of 244 American football fields. It is the largest landfill in Brazil and all of South America. Built in the late 1970s, it received close to 8,000 tons of trash daily, 70% of all the trash in the Rio metro area.