Solid waste management

Open Dumps (Landfill)

In the past, solid waste was usually accumulated in open dumps, where the refuse was piled up without being covered or otherwise protected. Common sites are natural low areas, such as swamps or floodplains; and hillside areas above or below towns. The waste is often piled as high as equipment allows.

Such dumping spoils scenic resources, pollute soil and water resources, and is a potential health hazard to plants, animals, and people. As a general rule, open dumps create a nuisance by being unsightly, providing breeding grounds for pests, creating a health hazard, polluting the air and sometimes polluting groundwater and surface water. A properly designed and well-managed landfill can be a hygienic and relatively inexpensive method of disposing of waste materials.

Sanitary Landfills                

A sanitary landfill is designed to concentrate and contain refuse (contrast to open dumping) without creating a nuisance or hazard to public health or safety. It is covered with a layer of compacted soil at the end of each day of operation or more frequently if necessary. Covering the waste in landfill is what makes the landfill sanitary. The compacted layer restricts (not eliminate) continued access to the waste by insects, rodents, and other animals, such as seagulls. It also isolates the refuse, minimizing the amount of surface water entering into and gas escaping from the waste.

                                                       

Modern sanitary landfills are engineered to include multiple barriers (double-lined), such as clay and plastic liners to limit movement of leachate; surface and subsurface drainage to collect leachate; system to collect methane gas produced as waste decomposes; and groundwater-monitoring to detect leaks of leachate below and adjacent to the landfill.                  

                                               

The production of methane gas by the anaerobic decomposition of organic wastes in a landfill can present a very serious explosion hazard if the gas is not collected (and possibly burned as an energy source).

Environmental Impacts of Landfills

• A major concern with regard to landfills is the potential water pollution from the rainwater that percolates through the wastes, dissolving and carrying away all organic and inorganic contaminants
• Many of the contaminants in landfill leachate are highly toxic and would create a serious pollution problem if they reach the groundwater
• The production of methane gas by the anaerobic decomposition of of organic wastes in a landfill can present a very serious explosion hazard if the gas is not collected
• Possibly burned as an energy source