Waste management methods vary widely between areas for many reasons, including type of waste material, nearby land uses and the area available.
Disposal
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Disposing of waste in a landfill involves burying waste, and many landfills were established in disused quarries or mines. Properly designed and well-managed landfills can be a hygienic and relatively inexpensive method of disposing of waste materials. When badly managed, they can create adverse environmental impacts such a win-blown litter, vermin and liquids leaching out to pollute groundwater. other common by-products of landfills are gases, mostly methane and carbon dioxide.
Modern landfills include methods to stop leaching, such as clay or plastic lining material. Deposited waste is normally compacted to increase its density and stability, ad covered to prevent attracting vermin. Many landfills also have landfill gas extraction systems installed to extract the landfill gas. Gas is pumped out of the landfill using perforated pipes and flared off or burnt in a gas engine to generate electricity.
Incineration
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Incineration involves combustion of waste material. Incinerators convert waste materials into heat, gas, steam and ash. It is recognised as a practical method of disposing of certain hazardous waste materials (such as biological medical waste), but it is controversial due to issues such as emission of gaseous pollutants. Some facilities burn waste in a furnace or boiler to generate heat, steam and/or electricity.