Landfills

Alandfillis any low area to be filled in for road building or for storing waste. More commonly, a landfill is a waste disposal site designed and constructed to accommodate municipal solid waste and hazardous waste while protecting against environmental and public health hazards.

One of the earliest forms of waste management was reported in 5th century b.c.e. in Greece where individuals were responsible for collecting garbage and transporting it to a dump site. Standard waste practices for centuries included land and water dumping of ashes, rubbish, and garbage, and household organic waste was often consumed by hogs. Such practices drew increased criticism in the late 19th and early 20th centuries, generating a new class of waste engineers and sanitarians that looked to a variety of alternatives to dispose of municipal solid wastes.

Efficient trash management in controlled landfills did not arise until the 1930s. The Fresno Municipal Sanitary Landfill, located three miles southwest of the City of Fresno, California, and which opened in 1937, is considered to have been the first modern, sanitary landfill. New techniques of trenching, compacting, and the daily covering of trash with soil were used on the Fresno site.

Daily coverings of soil layers reduce environmental and health problems, such as at this landfill in the UK.

Cities with populations of more than 100,000 adopted some form of organized refuse collection and disposal in the United States during the 1930s. Still, even into the 1970s, open and uncontrolled dumps were used to dispose of solid wastes, which increasingly consisted of discarded packaging materials associated with disposable household and industrial items. Often wastes of all types were burned on site. Open dumping caused a variety of environmental impacts, mainly through noxious odors, noise, birds, and smoke, and occasionally uncontrolled combustion occurred.

Most landfills today are regulated by environmental agencies to protect public health during waste disposal activities. Landfills are carefully designed and built into the ground to isolate trash from the surrounding environment. The purpose is to avoid any water-related connection between the waste and the surrounding environment, particularly groundwater. Landfills generally require at least one containment liner, generally made of compacted clay or a synthetic flexible membrane, to avoid leachate seepages into the surrounding soils and groundwater. Daily coverings of soil layers reduce environmental and health problems. Capping systems also avoid precipitation into the landfill and gas emissions into the atmosphere. A landfill siting plan and on-site environmental monitoring systems provide additional safeguards.

Continued problems with landfills include groundwater contamination from leakages, high operative and transport costs, and greenhouse gas emissions. Recent years have seen a shift from smaller to much bigger landfill sites, or mega-fills, some of which have disposal capacity equivalent to 1,000 football fields. Not only has urban waste amplified, its composition has changed from dense and almost completely organic to bulky and increasingly nonbiodegradable.

Changes in lifestyle patterns play a major role in waste generation, which is significantly higher in more affluent regions. Today's trash or garbage consists of everyday items such as product packaging, grass clippings, furniture, clothing, bottles, food scraps, newspapers, appliances, paint, and batteries. Besides household waste, landfills can also receive nonhazardous sludge, industrial solid waste, and construction and demolition debris. Even computers are being dumped in landfills.

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