Almost anything can be recycled, but certain things are more common

Описание: The use of paper in industrialized nations continues to increase, in some cases accounting for almost 20 percent of all household garbage [source:Essential Guide]. Although the trees used to make new paper are a renewable resource, old-growth forests are often chopped down to make room for the pulpwood trees, which are quickly planted and harvested to make paper. Recycled paper results in a significant net savings in terms of water and energy used, as well as pollutants emitted into the environment.
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Recycling assignment.doc

Almost anything can be recycled, but certain things are more common.

Paper 
The use of paper in industrialized nations continues to increase, in some cases accounting for almost 20 percent of all household garbage [source:
Essential Guide]. Although the trees used to make new paper are a renewable resource, old-growth forests are often chopped down to make room for the pulpwood trees, which are quickly planted and harvested to make paper. Recycled paper results in a significant net savings in terms of water and energy used, as well as pollutants emitted into the environment.

From curbside and workplace collections, paper is sorted based on the type of paper, how heavy it is, what it's used for, its color and whether it was previously recycled. Then a hot chemical and water bath reduces the paper to a soupy, fibrous substance. Magnetsgravity and filters then remove things like staples, glues and other unwanted chemicals from the pulp. The ink is removed by either a chemical wash, or by blowing the ink to the surface where it's skimmed off. The pulp -- which may be bleached -- is then sprayed and rolled into flat sheets, which are pressed and dried. Sometimes new pulp is added to the recycled pulp to make the paper stronger. The giant sheets of paper, when dry, are then cut into the proper size for resale back to consumers [source: Essential Guide].

Glass 
Recycling glass represents significant energy and cost savings over making virgin glass, because there's virtually no down-cycling when glass is recycled. There are two ways to recycle glass. Some companies collect bottles from their customers and thoroughly wash and disinfect them before reuse. Other glass recyclers sort the glass by color (clear, green and brown glass shouldn't mix because it'll give it a mottled effect). The glass is ground up into fine bits known as cullet, thoroughly sifted and filtered using 
lasers, magnets and sifters, then melted down and reformed into new glass.

Only glass used in containers like jars and bottles is commonly recycled. Window glass and glass used in light bulbs is too expensive and difficult to recycle.

Steel 
The recycling of scrap 
steel from cars and old buildings has a long history in the United States. Steel is relatively easy to recycle -- giant machines shred junk cars and construction waste. In addition, U.S. law requires a certain proportion of all steel to be made with recycled steel -- all U.S. steel contains at least 25 percent recycled steel.

Once sorted, scrap steel is melted down and re-refined into huge sheets or coils. These can be shipped to manufacturers to make car bodies or construction materials. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Paper recycling is the process of recovering waste paper and remaking it into new paper products. There are three categories of paper that can be used as feedstocks for making recycled paper: mill broke, pre-consumer waste, and post-consumer waste.[1] Mill broke is paper trimmings and other paper scrap from the manufacture of paper, and is recycled internally in a paper millPre-consumer waste is material which left the paper mill, which has been discarded before it was ready for consumer use. Post-consumer waste is material discarded after consumer use, such as old magazines, old newspapers, office waste, old telephone directories, and residential mixed paper.[2] Paper suitable for recycling is called "scrap paper". The industrial process of removing printing ink from paperfibers of recycled paper to make deinked pulp is called deinking.

Rationale for recycling

Industrialized paper making has an effect on the environment both upstream (where raw materials are acquired and processed) and downstream (waste-disposal impacts).[3] Recycling paper reduces this impact.

Today, 90% of paper pulp is made of wood. Paper production accounts for about 35% of felled trees,[4] and represents 1.2% of the world's total economic output.[5]Recycling one ton of newsprint saves about 1 ton of wood while recycling 1 ton of printing or copier paper saves slightly more than 2 tons of wood.[citation neededThis is because kraft pulping requires twice as much wood since it removes lignin to produce higher quality fibres than mechanical pulping processes. Relating tons of paper recycled to the number of trees not cut is meaningless, since tree size varies tremendously and is the major factor in how much paper can be made from how many trees.[6] Trees raised specifically for pulp production account for 16% of world pulp production, old growth forests 9% and second- and third- and more generation forests account for the balance.[4] Most pulp mill operators practice reforestation to ensure a continuing supply of trees.[citation neededThe Programme for the Endorsement of Forest Certification (PEFC) and the Forest Stewardship Council (FSC) certify paper made from trees harvested according to guidelines meant to ensure good forestry practices.[7] It has been estimated that recycling half the world’s paper would avoid the harvesting of 20 million acres (81,000 km²) of forestland.[8]

[edit]Energy

Energy consumption is reduced by recycling, although there is debate concerning the actual energy savings realized. The Energy Information Administration claims a 40% reduction in energy when paper is recycled versus paper made with unrecycled pulp,[9] while the Bureau of International Recycling (BIR) claims a 64% reduction.[10]Some calculations show that recycling one ton of newspaper saves about 4,000 kW·h (14 GJ) of electricity, although this may be too high (see comments below on unrecycled pulp). This is enough electricity to power a 3-bedroom European house for an entire year, or enough energy to heat and air-condition the average North American home for almost six months.[11] Recycling paper to make pulp may actually consume more fossil fuels than making new pulp via the kraft process; however, since these mills generate all of their energy from burning waste wood (bark, roots) and byproduct lignin.[12] Pulp mills producing new mechanical pulp use large amounts of energy; a very rough estimate of the electrical energy needed is 10 gigajoules per tonne of pulp (2500 kW·h per short ton),[13] usually fromhydroelectric generating plants.[citation neededRecycling mills purchase most of their energy from local power companies, and since recycling mills tend to be in urban areas, it is likely that the electricity is generated by burning fossil fuels.[citation needed]

[edit]Landfill use

About 35% of municipal solid waste (before recycling) by weight is paper and paper products.[14] Recycling 1 ton of newspaper eliminates 3 cubic meters of landfill.[15]Incineration of waste paper is usually preferable to landfilling since useful energy is generated.[citation neededOrganic materials, including paper, decompose in landfills, albeit sometimes slowly, releasing methane, a potent greenhouse gas. Many larger landfills now collect this methane for use as a biogas fuel. In highly urbanized areas, such as the northeastern US and most of Europe, land suitable for landfills is scarce and must be used carefully.

[edit]Water and air pollution

The United States Environmental Protection Agency‎ (EPA) has found that recycling causes 35% less water pollution and 74% less air pollution than making virgin paper.[16] Pulp mills can be sources of both air and water pollution, especially if they are producing bleached pulp. Modern mills produce considerably less pollution than those of a few decades ago. Recycling paper decreases the demand for virgin pulp and thus reduces the overall amount of air and water pollution associated with paper manufacture. Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (process chlorine free) if no chlorine-containing compounds were used in the recycling process.[17] However, recycling mills may have polluting by-products, such as sludge. De-inking at Cross Pointe's Miami, Ohio mill results in sludge weighing 22% of the weight of wastepaper recycled.[18]

[edit]Criticism

See also: Recycling

Some of the claimed benefits of paper recycling have fallen under criticism, such as the claim that recycling saves trees, reduces energy consumption, reduces pollution, creates desirable jobs, and saves money.

[edit]Recycling facts and figures

In the mid-19th century, there was an increased demand for books and writing material. Up to that time, paper manufacturers had used discarded linen rags for paper, but supply could not keep up with the increased demand. Books were bought at auctions for the purpose of recycling fiber content into new paper, at least in the United Kingdom, by the beginning of the 19th century.[19]

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