recycling, the process of recovering and reusing waste products—from household use, manufacturing, agriculture, and business—and thereby reducing their burden on the environment. During World War I and World War II, shortages of essential materials led to collection drives for silk, rubber, and other commodities. In recent years the environmental benefits of recycling have become a major component of waste management programs.
Waste Disposal and Recycling
For many years direct recycling by producers of surplus and defective materials constituted the main form of recycling. However, indirect recycling, the recycling of materials after their use by consumers, became the focus of activity in the 1990s. For some time, most solid waste has been deposited in landfills or dumps. Landfills are filling up, however, and disposal of wastes in them has led to environmental problems. Also, government (which had little authority over disposal of wastes until the 1970s) now has extensive regulatory powers.
A growing alternative to such disposal is recycling. Industry has found that when it undertakes serious recycling programs, the savings can sometimes be considerable. In addition to reducing manufacturing and materials costs, such programs can insulate the companies from liability for environmental violations. Agriculture, which is the cause of much environmental degradation, can use organic recycling, or the reuse of manure and crop residues (sometimes called "green manure" ).
Water, in one sense, is always recycled, inasmuch as there is a finite amount of it available on earth and it constantly moves through its cycle of evaporation, condensation, and precipitation. Deliberate programs for recycling water include use of wetlands as areas to filter harmful wastes from the substance, or using partly treated sewage for raising fish. Municipal sewage- and water-treatment plants, of course, are fundamental recycling agents.
The individual consumer plays a large part in recycling. Originally, household containers such as beverage cans and bottles were recycled as a matter of course, with a glass beer container or milk bottle being refilled as many as 30 times; in 1935, brewers began putting their products in nonrefillable, "one-way" cans for the convenience of customers, and soon glass containers were declared disposable as well. With the rise of environmentalism in the early 1970s, recycling regained favor. Several states instituted deposit laws for beverage containers; a 5- or 10-cent deposit was charged the consumer at the time of purchase for each can or bottle, then refunded when the container was returned to a store or recycling center. Newspapers take up much volume in landfills, and some recycling programs seek to collect them (along with other sorted categories of waste, such as organic matter, bones, and plastic).
Use of Recycled Materials
In 1996, 27% of solid waste in the United States was recycled. Products that are recycled in large quantities include paper and paperboard, ferrous metals, aluminum and other nonferrous metals, glass, plastics, and yard wastes. Although many local communities have instituted comprehensive recycling programs, these remain expensive. Because the quality of recycled items is often inferior (often due to the mixture or age of the materials in the items being recycled) and not suitable for their original purpose, the price for many recycled materials remains low and makes recycling economically nonviable in some instances. In an attempt to solve this problem, new uses have been created for recovered waste material. Crushed glass, for instance, can be substituted for gravel or sand in road surfacing and other construction applications; the resulting product is called "glassphalt." Scientists and entrepreneurs are also working on ways to turn the world's growing piles of discarded automobile tires into new products or to use them to generate safe energy.
See R. E. Easterling, Reuse of Disposables (1983); W. U. Chandler, Materials Recycling (1983); C. Polprasert, Organic Waste Recycling (1989).