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

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

Тип работы: Реферат
Предмет: Экология
Язык документа: Русский
Год сдачи: 2008
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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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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 km?) 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]

Internationally, about half of all recovered paper comes from converting losses (pre-consumer recycling), such as shavings and unsold periodicals; approximately one third comes from household or post-consumer waste.[20]

Some statistics on paper consumption:

  • The average per capita paper use worldwide was 110 pounds (50 kg).[21]
  • It is estimated that 95% of business information is still stored on paper. [Source: International Institute for Environment and Development (IIED) Discussion Paper (IIED, London, September 1996)]
  • Recycling 1 short ton (0.91 t) of paper saves 17 mature trees, 7 thousand US gallons (26 m3) of water, 3 cubic yards (2.3 m3) of landfill space, 2 barrels of oil (84 US gal or 320 l), and 4,100 kilowatt-hours (15 GJ) of electricity — enough energy to power the average American home for six months.[22]
  • Although paper is traditionally identified with reading and writing, communications has now been replaced by packaging as the single largest category of paper use at 41% of all paper used.[23]
  • 115 billion sheets of paper are used annually for personal computers.[24] The average web user prints 28 pages daily.[25]
  • Most corrugated fiberboard boxes have over 25% recycled fibers[citation needed]. Some are 100% recycled fiber.

[edit]Paper recycling by region

[edit]European Union

Paper recovery in Europe has a long history and has grown into a mature organization. The European papermakers and converters work together to meet the requirements of the European Commission and national governments. Their aim is the reduction of the environmental impact of waste during manufacturing, converting/printing, collecting, sorting and recycling processes to ensure the optimal and environmentally sound recycling of used paper and board products. In 2004 the paper recycling rate in Europe was 54.6% or 45.5 million short tons (41.3 Mt).[26]The recycling rate in Europe reached 64.5% in 2007, which confirms that the industry is on the path to meeting its voluntary target of 66% by 2010.[27]

[edit]Japan

Municipal collections of paper for recycling are in place. However, according to theYomiuri Shimbun, in 2008, eight paper manufacturers in Japan have admitted to intentionally mislabeling recycled paper products, exaggerating the amount of recycled paper used.[citation needed]

[edit]United States of America

Recycling has long been practiced in the United States. The history of paper recycling has several dates of importance:

  • 1690: The first paper mill to use recycled linen was established by the Rittenhouse family.[28]
  • 1896: The first major recycling center was started by the Benedetto family in New York City, where they collected rags, newspaper, and trash with a pushcart.
  • 1993: The first year when more paper was recycled than was buried in landfills.[29]

Today, over half of the material used to make paper is recovered waste.[30] Paper products are the largest component of municipal solid waste, making up more than 40% of the composition of landfills.[31][32] In 2006, a record 53.4% of the paper used in the US (or 53.5 million tons) was recovered for recycling.[33] This is up from a 1990 recovery rate of 33.5%.[33] The US paper industry has set a goal to recover 55 percent of all the paper used in the US by 2012. Paper packaging recovery, specific to paper products used by the packaging industry, was responsible for about 77% of packaging materials recycled with more than 24 million pounds recovered in 2005.[34]

By 1998, some 9,000 curbside programs and 12,000 recyclable drop-off centers had sprouted up across the US for recycles collection. As of 1999, 480 materials recovery facilities had been established to process the collected materials.[35]

In 2008, the global financial crisis resulted in the price of old newspapers to drop in the US from $130 to $40 per short ton ($140/t to $45/t) in October.[36]

The first piece of paper as we know it was produced from rags in AD 105 by Ts'ai Luin, who was part of the Eastern Han Court of the Chinese Emperor Ho Ti.

Paper is made from cellulose fibre, the source of which can be pulped wood, or a variety of other materials such as rags, cotton, grasses, sugar cane, straw, waste paper, or even elephant dung! In this country, wood pulp is the most common source material for the manufacture of virgin paper, i.e. paper which has no recycled content.

In 2004 recycled paper and board provided about 74% of the source materials for the 6.2million tonnes of paper manufactured in the UK's 76 paper and board mills. A further 7.7 million tonnes were imported.

There are different sources of waste fibre used as a source material for manufacturing recycled paper.

Mill Broke is "waste" paper which has never been used, either printers' off cuts or rolls damaged during production. When mixed with water the fibres are freed into pulp. The National Association of Paper Manufacturers does not recognise a paper as recycled if it contains more than 25% mill broke and/or virgin wood pulp.

The recycling of paper which has been printed on and used is known as "post-consumer waste". It is more problematic, (see de-inking below), but it is still worthwhile. Paper cannot be recycled indefinitely, it can only be recycled 4-6 times, as the fibres get shorter and weaker each time. Some virgin pulp must be introduced into the process to maintain the strength and quality of the fibre, so no matter how much we recycle we will never eradicate the need for virgin fibre. 

Why bother?

 

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In 2003/04, paper and card accounted for almost a third of all household waste collected for recycling, with almost 1.3 million tonnes being collected in England. This means, however, that there is still a considerable amount that isn't recycled and is largely going to landfill or incineration.

Although the raw material for making paper is predominantly trees, it is a common misconception that recycling waste paper saves trees. Trees are grown for commercial use and harvested as a long term crop with new trees planted to replace those cut down. In addition, papermakers are able to use the parts of the trees that cannot be used in other industries such as construction and furniture making. Different species of trees provide fibres that are used in different types of paper. Coniferous softwoods such as spruce, pine birch and cedar produce fibres which are long (average fibre length is 3mm) and are used to make papers which have a lot of strength. Hardwoods such as birch and aspen do not grow as fast as softwoods and produce short fibres (average fibre length 1mm) which are used for bulky papers such as writing paper and fluting, which is the middle part of cardboard. Nearly all paper is made from wood grown in these "sustainable" forests. The more important environmental issues are:

  1. The nature of forests and where they are situated. As the demand for paper has increased, more timber has been needed to meet the demand for wood pulp. In some cases this has meant the loss of valuable wildlife habitats and ecosystems, as old forests have been replaced by managed plantations, usually of fast-growing conifers. The lack of tree species diversity in managed forests has a direct impact on the biodiversity of the whole forest.
  2. By using waste paper to produce new paper disposal problems are reduced.

    For every tonne of paper used for recycling the savings are:

    • at least 30000litres of water
    • 3000 - 4000 KWh electricity (enough for an average 3 bedroom house for one year)
    • 95% of air pollution.
  1. Producing recycled paper involves between 28 - 70% less energy consumption than virgin paper and uses less water. This is because most of the energy used in papermaking is the pulping needed to turn wood into paper.
  2. Recycled paper produces fewer polluting emissions to air (95% of air pollution) and water. Recycled paper is not usually re-bleached and where it is, oxygen rather than chlorine is usually used. This reduces the amount of dioxins which are released into the environment as a by-product of the chlorine bleaching processes.
  3. Paper is a biodegradable material. This means that when it goes to landfill, as it rots, it produces methane, which is a potent greenhouse gas (20 times more potent than carbon dioxide). It is becoming increasingly accepted that global warming is a reality, and that methane and carbon dioxide emissions have to be reduced to lessen its effects. Please see our energy information sheet for more information on this.

What are the main types of paper in everyday use which can be recycled?

  1. Office white paper
  2. Newspapers, magazines, telephone directories and pamphlets
  3. Cardboard
  4. Mixed or coloured paper
  5. Computer print out paper

If you have junk mail, windowed envelopes, or Yellow Pages then please contact you local authority. These materials can be more awkward to recycle, and the availability of recycling facilities varies around the country.

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