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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
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.
The use of paper in industrialized nations continues to increase, in
some cases accounting for almost 20 percent of all household garbage
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. Magnets, gravity 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].
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
bulbs is too expensive
and difficult to recycle.
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. Mill broke is paper trimmings
and other paper scrap from the manufacture of paper, and is recycled
internally in a paper
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. 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). Recycling paper reduces this impact.
Today, 90% of paper pulp is
made of wood. Paper production accounts for about 35% of felled trees, and represents 1.2% of the world's
total economic output.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
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. 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. Most pulp mill operators practice reforestation to ensure a continuing supply of trees. The 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. It has been estimated that recycling
half the world’s paper would avoid the harvesting of 20 million acres
(81,000 km?) of forestland.
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, while the Bureau of International Recycling
(BIR) claims a 64% reduction.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. 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. 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), usually fromhydroelectric generating
plants. Recycling 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.
About 35% of municipal solid
waste (before recycling) by weight is paper and paper products. Recycling 1 ton of newspaper eliminates
3 cubic meters of landfill.Incineration of waste paper is usually preferable
to landfilling since useful energy is generated. Organic 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.
Water and air pollution
States Environmental Protection Agency? (EPA)
has found that recycling causes 35% less water pollution and 74% less
air pollution than making virgin paper. 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,
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. 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.
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.
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.
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.
Some statistics on paper consumption:
- The average per
capita paper use worldwide was 110 pounds (50 kg).
- 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.
- 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.
- 115 billion sheets
of paper are used annually for personal computers. The average web user prints 28 pages
- Most corrugated
fiberboard boxes have over 25% recycled fibers. Some are 100% recycled
Paper recycling by region
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).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.
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.
United States of America
Recycling has long been practiced
in the United States. The history of paper recycling has several dates
- 1690: The first
paper mill to use recycled linen was established by the Rittenhouse
- 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.
Today, over half of the material
used to make paper is recovered waste. Paper products are the largest component
solid waste, making
up more than 40% of the composition of landfills. In 2006, a record 53.4% of the paper
used in the US (or 53.5 million tons) was recovered for recycling. This is up from a 1990 recovery rate
of 33.5%. 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.
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.
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.
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
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.
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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:
- 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.
- By using waste paper
to produce new paper disposal problems are reduced.
every tonne of paper used for recycling the savings are:
least 30000litres of water
- 4000 KWh electricity (enough for an average 3 bedroom house for one
- 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.
- 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
- 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.
the main types of paper in everyday use which can be recycled?
- Office white paper
- Newspapers, magazines,
telephone directories and pamphlets
- Mixed or coloured
- Computer print out
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.