Science Fair Project Encyclopedia
Recycling is the reuse of materials that would otherwise be considered waste. Recycled materials can be derived from pre-consumer waste (materials used in manufacturing) or post-consumer waste (materials discarded by the consumer).
Many man-made products are not readily biodegradable and take up space in landfills or must be incinerated. Recycling is an alternative to this. In theory, recycling would allow a continuing reuse of materials for the same purpose. In practice, recycling most often extends the useful life of a material, but in a less-versatile form. For example, when paper is recycled, the fibers shorten, making it less useful for high grade papers. Other materials can suffer from contamination, making them unsuitable for food packaging.
Consumer recycling has succeeded mostly in reducing industrial consumption of energy and water. Production of materials such as aluminum or glass requires large amounts electricity or fossil fuels. The recycling of such materials is profitable and prevents a substantial amount of greenhouse gas emissions.
Skeptics believe, with the exception of aluminum cans, that recycling is wasteful. In particular, the market for recycled materials is limited, and using recycled materials may be more expensive for manufacturers than new raw materials. As a result, state support for recycling may be more expensive than alternatives such as landfill; recycling efforts in New York City cost $57 million per year.1 However, recycling becomes relatively cheaper when externalities associated with raw material extraction and landfill (or incineration) are included, especially environmental and health effects. Recycling may still be socially efficient even when carried out at a financial loss - although an alternative to avoid this would be to tax raw material use appropriately so that prices fully reflect all the costs involved, instead of subsidising recycling.
Of the 24 OECD-countries where figures were available, only 16% of household waste was recycled in 2002. A number of U.S. states, such as Oregon,Connecticut, Delaware, Maine, Vermont, Massachusetts, Iowa, and New York have passed laws that establish deposits or refund values on beverage containers in order to promote recycling.
One form of recycling is the reuse of goods, especially bottles. Reuse is distinguished from most forms of recycling, where the good is reduced to a raw material and used in the making of a new good (eg crushing of bottles to make glass for new bottles). Refillable bottles are used extensively in many European countries; for example in Denmark, 98% of bottles are refillable, and 98% of those are returned by consumers.  These systems are typically supported by deposit laws and other regulations.
In the former East Germany, biological household waste was collected and used as fodder for pigs. This integrated system was made possible by the state's control of agriculture; the complexities of continuing it in a market economy after German reunification meant the system had to be discontinued. Biological household waste is still collected separately in some towns in Germany, and may be used for fertiliser or landfilled in more sensitive locations where other waste cannot be.
- Autonomous building
- Resin identification code
- Ship-Submarine recycling program
- Recycling Cell Phones
- Forced Recycling Is a Waste, Logomasini Op-Ed in The Wall Street Journal, Angela Logomasini, March 19, 2002
- Energy conservation
- Fuji Xerox
- Materials Recovery Facility
- Recycling of PET Bottles
- Thermal depolymerization
- Waste management
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