Science Fair Project Encyclopedia
- For other uses of the word, see Waste (disambiguation).
Waste is unwanted or undesired material left over after the completion of a process. "Waste" is a human concept: in natural processes there is no waste, only inert end products.
Waste can exist in any phase of matter (solid, liquid, or gas). When released in the latter two states, gas especially, the wastes are referred to as emissions. It is usually strongly linked with pollution.
Sources of waste
Waste produced in the wild is reintegrated through natural recycling processes, such as dry leaves in a forest decomposing into soil. Outside of the wild these wastes may become problematic, such as dry leaves in an urban environment. The highest volume of waste, outside of nature, comes from human industrial activity: mining, industrial manufacture, consumer use, and so on1. Almost all manufactured products are destined to become waste at some point in time, with a volume of waste production roughly similar to the volume of resource consumption.
Post-consumer waste is the waste produced by the end-user (the garbage one puts outside in the trash can). This is the waste people usually think of. But though the most visible, this is very small compared to the waste created in the process of mining and production.
Human waste is a term in the English language usually used to refer to byproducts of digestion, such as feces and urine. Human waste can be a serious health hazard, as it is a good vector for both viral and bacterial diseases. A major accomplishment of human civilization has been the reduction of disease transmission via human waste through the practice of hygiene and sanitation, including the development of theories of sewage systems and plumbing. Human waste can be reduced and reused through use of greywater, waterless urinals and humanure systems. In very rural places without sewage systems, small populations allow for the continued use of honey buckets and sewage lagoons without the threat of disease presented by places with more dense populations.
- Total waste generation by sector ? EEA Countries 1992-1997, European Environmental Agency, retrieved 2005/01/05 the above URI.
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