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Recycling

2007 Schools Wikipedia Selection. Related subjects: Environment

   The international recycling symbol.
   The international recycling symbol.
           Environmental science
   Environmental technology
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     * Recycling
     * Renewable energy
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   Recycling is the reprocessing of materials into new products. Recycling
   prevents useful material resources being wasted, reduces the
   consumption of raw materials and reduces energy usage, and hence
   greenhouse gas emissions, compared to virgin production. Recycling is a
   key concept of modern waste management and is the third component of
   the waste hierarchy.

   Recyclable materials, also called "recyclables" or "recyclates", may
   originate from a wide range of sources including the home and industry.
   They include glass, paper, aluminium, asphalt, iron, textiles and
   plastics. Biodegradable waste, such as food waste or garden waste, is
   also recyclable with the assistance of micro-organisms through
   composting or anaerobic digestion.

   Recyclates need to be sorted and separated into material types.
   Contamination of the recylates with other materials must be prevented
   to increase the recyclates value and facilitate easier reprocessing for
   the ultimate recycling facility. This sorting can be performed either
   by the producer of the waste or within semi- or fully-automated
   materials recovery facilities.

   There are two common household methods of helping increase recycling.
   Firstly kerbside collection (US: curbside collection) is where
   consumers leave presorted materials for recycling at the front of their
   property, typically in boxes or sacks to be collected by a recycling
   vehicle. Alternatively, with a "bring system", the householder may take
   the materials to recycling banks or civic amenity centres where
   recyclates are placed into recycling bins based on the type of
   material.

   Recycling does not include reuse where items retain their existing form
   for other purposes without the need for reprocessing.

History

   Recycling and rubbish bin in a German railway station.
   Recycling and rubbish bin in a German railway station.

   Recycling has been a common practice throughout human history. In pre-
   industrial times, scrap made of bronze and other precious metals was
   collected in Europe and melted down for perpetual reuse, and in Britain
   dust and ash from wood and coal fires was downcycled as a base material
   in brick making. The main driver for these types of recycling was the
   economic advantage of obtaining recycled feedstock instead of acquiring
   virgin material, as well as a lack of public waste removal in ever
   more-populated sites.

   Paper recycling began in Britain in 1921, when the British Waste Paper
   Association was established to encourage trade in waste paper
   recycling.

   Resource shortages caused by the world wars, and other such
   world-changing occurrences greatly encouraged recycling. Massive
   government promotion campaigns were carried out in World War II in
   every country involved in the war, urging citizens to donate metals and
   conserve fibre, as a matter of significant patriotic importance.
   Resource conservation programs established during the war were
   continued in some countries without an abundance of natural resources,
   such as Japan, after the war ended.

   In the USA, the next big investment in recycling occurred in the 1970s,
   due to rising energy costs (recycling aluminium uses only 5% of the
   energy required by virgin production; glass, paper and metals have less
   dramatic but very significant energy savings when recycled feedstock is
   used). The passage of the Clean Water Act of 1977 in the USA created
   strong demand for bleached paper (office paper whose fibre has already
   been bleached white increased in value as water effluent became more
   expensive).

   In 1973, the city of Berkeley, California began one of the first
   curbside collection programs with monthly pick ups of newspapers from
   residences. Since then several countries have started and expanded
   various doorstep collection schemes.

   One event that initiated recycling efforts occurred in 1989 when the
   city of Berkeley, California, banned the use of polystyrene packaging
   for keeping McDonald's hamburgers warm. One effect of this ban was to
   raise the ire of management at Dow Chemical, the world's largest
   manufacturer of polystyrene, which led to the first major effort to
   show that plastics can be recycled. By 1999, there were 1,677 companies
   in the USA alone involved in the post-consumer plastics recycling
   business.

Benefits

   Recycling is beneficial in two ways: it reduces the inputs (energy and
   raw materials) to a production system and reduces the amount of waste
   produced for disposal.

   Some materials like aluminium can be recycled indefinitely as there is
   no change to the materials. Other recycled materials like paper require
   a percentage of raw materials (wood fibers) to be added to compensate
   for the degradation of existing fibers.

   Since the materials being processed are purer, less energy is needed to
   process them and less energy is needed to transport from the place of
   extraction (e.g. bauxite/aluminium ore mines in Brazil or coniferous
   forests in Scandinavia).

   This reduces the environmental, social, and usually the economic costs
   of manufacturing.

   For example, bauxite mines in Brazil displace indigenous people, create
   noise pollution from blasting, machinery and transport, and create air
   pollution in the form of particulates (dust). The habitat loss and
   visual destruction is also negative both to the aesthetic qualities of
   the areas and the local environment. However, the mines do provide
   employment and revenue to the local population and economy, promoting
   development of the country as a whole.

   Recycling aluminium saves 95% of the energy cost of processing new
   aluminium because the melting temperature is reduced from 900 °C to 600
   °C.

   The most commonly used methods for waste disposal (landfill, proloysis,
   incineration) are environmentally damaging and unsustainable. Therefore
   any way to reduce the volume of waste being disposed in this fashion
   are beneficial. The maximum environmental benefit is gained by waste
   minimization (reducing the amount of waste produced), and reusing items
   in their current form such as refilling bottles.

   All recycling techniques consume energy, for transportation and
   processing, and some also use considerable amounts of water.

   The desired order for environmental sustainability is:
     * Reduce
     * Reuse
     * Recycle

Comparing recycling with normal extraction

   Aluminium
     * Recycling 1000 kg of aluminium saves up to 8000 kg of bauxite, four
       kg of chemical products and 14000 kW·h of electricity.
     * It takes 20 times more energy to make aluminium from bauxite ore
       than using recycled aluminium.

   Glass
     * A 20% reduction in emissions from glass furnaces and up to 32%
       reduction in energy usage.
     * For every 1000 kg of recycled glass used, approx 315 kg of carbon
       dioxide and 1,200 kg of raw materials are spared.

   Paper
     * 1000 kg of paper from recycled material conserves about 7,000 US
       gal (26,000 L) of water, 17-31 trees and 4,000 kW·h of electricity,
       and reduces the rate of virgin forests being cut to make tree
       farms.
     * Milling paper from recycled paper uses 20% less energy than it does
       to make paper from fresh paper trees grown on tree farms at the
       cost of more pollution caused by additional transportation and
       chemical cleaning treatment.

Drawbacks

   There may also be drawbacks with the collection methods associated with
   recycling. Increasing collections of separated wastes adds to vehicle
   movements and the production of carbon dioxide. This may be negated
   however by centralized facilities such as some advanced material
   recovery facilities of mechanical biological treatment systems for the
   separation of mixed wastes.

   Perverse consequences from mercury recycling have been cited recently
   by the Wall Street Journal (April 20, 2006). The article traces mercury
   recovered from USA recycling programs into sales of mercury for
   alluvial mining activities in Brazil. During the autumn of 2006, the EU
   banned the export of liquid mercury (Europe has no mercury mining, only
   recovery from recycling). A full life cycle analysis prior to
   institution of recycling programs may reduce the risk of unintended
   environmental consequences.

Recycling techniques

   Base layer of asphalt concrete
   Base layer of asphalt concrete

   Many different materials can be recycled but each type requires a
   different technique.

Aggregates & concrete

   Concrete aggregate collected from demolition sites is put through a
   crushing machine, often along with asphalt, bricks, dirt, and rocks.
   Smaller pieces of concrete are used as gravel for new construction
   projects. Crushed recycled concrete can also be used as the dry
   aggregate for brand new concrete if it is free of contaminants.

Batteries

   Some batteries contain toxic heavy metals
   Some batteries contain toxic heavy metals

   The large variation in size and type of batteries makes their recycling
   extremely difficult: they must first be sorted into similar kinds and
   each kind requires an individual recycling process. Additionally, older
   batteries contain mercury and cadmium, harmful materials which must be
   handled with care.

Biodegradable waste

   Anaerobic digesters produce biogas and soil improver from organic
   wastes
   Anaerobic digesters produce biogas and soil improver from organic
   wastes

   Biodegradable waste can be recycled into useful material by biological
   decomposition. There are two mechanisms by which this can occur. The
   most common mechanism of recycling of household organic waste is home
   composting or municipal curbside collection of green wastes sent to
   large scale composting plants.

   Alternatively organic waste can be converted into biogas and soil
   improver using anaerobic digestion. Here organic wastes are broken down
   by anaerobic microorganisms in biogas plants. The biogas can be
   converted into renewable electricity or burnt for environmentally
   friendly heating. Advanced technologies such as mechanical biological
   treatment are able to sort the recyclable elements of the waste out
   before biological treatment by either composting, anaerobic digestion
   or biodrying.

Electronics disassembly and reclamation

   Abandoned monitor
   Abandoned monitor

   The direct disposal of electrical equipment—such as old computers and
   mobile phones is banned in many areas due to the toxic contents of
   certain components. The recycling process works by mechanically
   separating the metals, plastics and circuit boards contained in the
   appliance. When this is done on a large scale at an electronic waste
   recycling plant, component recovery can be achieved in a cost-effective
   manner.

   Electronic devices, including audio-visual components (televisions,
   VCRs, stereo equipment), mobile phones and other hand-held devices, and
   computer components, contain valuable elements and substances suitable
   for reclamation, including lead, copper, and gold. They also contain a
   plethora of toxic substances such as dioxins, PCBs, cadmium, chromium,
   radioactive isotopes, and mercury. Additionally, the processing
   required to reclaim the precious substances (including incineration and
   acid treatments) release, generate and synthesize further toxic
   by-products.

   In the United States, an estimated 70% of heavy metals in landfills
   come from discarded electronics.Some regional governments are
   attempting to curtail the accumulation of electronics in landfills by
   passing laws obligating manufacturers and consumers to recycle these
   devices, but because in many cases safe dismantlement of these devices
   in accordance with first world safety standards is unprofitable,
   historically much of the electronic waste has been shipped to countries
   with lower or less rigorously-enforced safety protocols. Places like
   Guiyu, China dismantle tonnes of electronics every year, profiting from
   the sale of precious metals, but at the cost of the local environment
   and the health of its residents.

   Mining to produce the same metals, to meet demand for finished products
   in the west, also occurs in the same countries, and the United Nations
   Conference on Trade and Development (UNCTAD) has recommended that
   restrictions against recycling exports be balanced against the
   environmental costs of recovering those materials from mining. Hard
   rock mining in the USA produces 45% of all toxics produced by all USA
   industries (2001 US EPA Toxics Release Inventory).

Printer ink cartridges & toners

   Printer ink cartridges can be recycled. They are sorted into different
   brands and models which are then resold back to the companies that
   created these cartridges. The companies then refill the ink reservoir
   which can be sold back to consumers. Toner cartridges are recycled the
   same way as ink cartridges, using toner instead of ink. This method of
   recycling is highly efficient as there is no energy spent on melting
   and recreating the recycled object itself.

Ferrous metals

   Steel crushed and baled for recycling
   Steel crushed and baled for recycling

   Iron and steel are the world's most recycled materials, and among the
   easiest materials to recycle, as they can be separated magnetically
   from the waste stream. Recycling is via a steelworks: scrap is either
   remelted in an Electric Arc Furnace (90-100% scrap), or used as part of
   the charge in a Basic Oxygen Furnace (around 25% scrap). Any grade of
   steel can be recycled to top quality new metal, with no 'downgrading'
   from prime to lower quality materials as steel is recycled repeatedly.
   42% of crude steel produced is recycled material.

Non-ferrous metals

   A piece of aluminium metal
   A piece of aluminium metal

   Aluminium is shredded and ground into small pieces. These pieces are
   melted in an aluminium smelter to produce molten aluminium. By this
   stage the recycled aluminium is indistinguishable from virgin aluminium
   and further processing is identical for both.

   Due to aluminium ore having a high melting point, large amount of
   energy are required to extract aluminium from ore, making the
   environmental benefits of recycling aluminium enormous. Approximately
   5% of the CO[2] is produced during the recycling process compared to
   producing raw aluminium (and an even smaller percentage when
   considering the complete cycle of mining and transporting the
   aluminium). Also, as open-cut mining most often used for obtaining
   aluminium ore, mining destroys large sections of natural land.

   For example, an aluminium can is 100% recyclable every time it is
   recycled, it saves enough energy to watch television for about three
   hours (compared to mining and producing a new can).
   Public glass waste collection point in a neighborhood area for
   separating clear, green and amber glass
   Public glass waste collection point in a neighbourhood area for
   separating clear, green and amber glass

Glass

   Glass bottles and jars are gathered via curbside collection schemes and
   bottle banks, where the glass may be sorted into colour categories. The
   collected glass cullet is taken to a glass recycling plant where it is
   monitored for purity and contaminants are removed. The cullet is
   crushed and added to a raw material mix in a melting furnace. It is
   then mechanically blown or molded into new jars or bottles. Glass
   cullet is also used in the construction industry for aggregate and
   glassphalt. Glassphalt is a road-laying material which comprises around
   30% recycled glass. Glass can be recycled indefinitely as its structure
   does not deteriorate when reprocessed.

Paper

   International Paper Company: Kraft paper mill
   International Paper Company: Kraft paper mill

   Recycled paper is made from waste paper, usually mixed with fresh wood
   pulp. If the paper contains ink, it must be deinked. This also removes
   fillers, clays, and fibre fragments.

   If everyone recycled their newspaper each day it would save 41000
   trees. Almost all paper can be recycled today, but some types are
   harder to recycle than others. Kraft paper, papers coated with plastic
   or aluminium foil, and papers that are waxed, pasted, or gummed are
   usually not recycled because the process is too expensive. Different
   types of paper are usually sorted before recycling, such as newspapers
   and cardboard boxes.

   Different grades of paper are recycled into different types of new
   products. Old newspapers are usually made into new newsprint, egg
   cartons, or paperboard. Old corrugated boxes are made into new
   corrugated boxes or paperboard. High-grade white office paper can be
   made into almost any new paper product: stationery, newsprint,
   magazines, or books.

   Sometimes recyclers ask for the removal of the glossy inserts from
   newspapers because they are a different type of paper. Glossy inserts
   have a heavy clay coating that some paper mills cannot accept. Since
   the paper is weighed down by the clay coating, a paper mill gets more
   recyclable fibers from a ton of pure newsprint.

   Paper can only be recycled a finite number of times due to the
   shortening of paper fibers making the material less versatile. Often it
   will be mixed with a quantity of virgin material, referred to as
   downcycling. This does not however exclude the material from being used
   in other processes such as composting or anaerobic digestion, where
   further value can be extracted from the material in the form of compost
   or biogas.

Plastic

   Plastic recycling is the process of recovering scrap or waste plastics
   and reprocessing the material into useful products. Compared to glass
   or metallic materials, plastic poses unique challenges - because of the
   massive number of types of plastic, they each carry a resin
   identification code, and must be sorted before they can be recycled.
   This can be costly - while metals can be sorted using electromagnets,
   no such 'easy sorting' capability exists for plastics. In addition to
   this, while labels do not need to be removed from bottles for
   recycling, lids are often made from a different kind of non-recyclable
   plastic.

   Plastics recycling rates lag far behind those of other items, such as
   newspaper and aluminium; consumers are typically unsure of how to
   recycle plastics, and compared to paper and metals fewer recycling
   facilities exist.

   Finally, recycled plastic is less appealing to manufacturers than new
   plastic.

Shipbreaking

   Ship breaking in Bangladesh
   Ship breaking in Bangladesh
   Ship breaking in Bangladesh
   Ship breaking in Bangladesh

   A form of metal recovery associated to recycling is " shipbreaking".
   This is the process of breaking a ship into smaller, recyclable pieces
   of metal. It often has a number of major drawbacks to the local
   community and the local environment where shipbreaking occurs.

   Shipbreaking tends to occur in poor countries where lack of or
   insufficient safety standards, labor laws and wage agreements makes
   them a lucrative area for demolition work. India, Pakistan, Turkey and
   Bangladesh make up the majority of these countries.

   Toxic material in the form of metals, gas, fumes and exhaust often
   contaminate a large area surrounding the ship breaking yards, including
   nearby villages and sleeping quarters for the workers, which are
   commonly located near the yards.

   Material such as paint, electrical equipment, wire, anodes and coatings
   are often burned or simply dumped in the dismantling process. This
   releases metals such as mercury, lead, arsenic and chromium.

   Polychlorinated organic compounds are another source of toxic material
   that can be found in transformers and cable insulation often burned or
   dumped in and around the ship breaking yard.

   It is believed that many of the social, economical and environmental
   drawback in shipbreaking could be alleviated greatly by adhering to
   safe handling of the recycling process, or the ship owner
   decontaminating the toxins from the ship before it gets sent to be
   demolished.

Textiles

   When considering textile recycling one must understand what the
   material consists of. Most textiles are composites of cotton
   (biodegradable material) and synthetic plastics. The textile's
   composition will affect its durability and method of recycling.

   Workers sort and separate collected textiles into good quality clothing
   and shoes which can be reused or worn. These sorting facilities are in
   a trend of being moved from developed countries such as the UK to
   developing countries.

   Damaged textiles are further sorted into grades to make industrial
   wiping cloths and for use in paper manufacture or material which is
   suitable for fibre reclamation and filling products. If textile
   reprocessors receive wet or soiled clothes however, these may still end
   up being disposed of in landfill, as the washing and drying facilities
   are not present at sorting units.

   Fibre reclamation mills sort textiles according to fibre type and
   colour. Colour sorting eliminates the need to re-dye the recycled
   textiles. The textiles are shredded into "shoddy" fibres and blended
   with other selected fibres, depending on the intended end use of the
   recycled yarn. The blended mixture is carded to clean and mix the
   fibres and spun ready for weaving or knitting. The fibres can also be
   compressed for mattress production. Textiles sent to the flocking
   industry are shredded to make filling material for car insulation,
   roofing felts, loudspeaker cones, panel linings and furniture padding.

The International Universal Recycling Codes

   Symbol Code Description
   PLASTICS
   #1 PET(E) Polyethylene Terephthalate
   #2 PE-HD High-Density Polyethylene
   #3 PVC Polyvinyl Chloride
   #4 PE-LD Low-Density Polyethylene
   #5 PP Polypropylene
   # 6 PS Polystyrene
   #7 O(ther) plastic All other plastics
   Batteries
   #8 Lead Lead-Acid Battery
   #9 Alkaline Alkaline Battery
   #10 NiCD Nickel-cadmium battery
   #11 NiMH Nickel metal hydride Battery
   #12 Li Lithium Battery
   #13 SO(Z) Silver-oxide battery
   #14 CZ Zinc-carbon battery
   PAPER
   #20 C PAP (PCB) cardboard
   #21 PAP Other paper, mixed paper ( magazines, mail)
   #23 PBD (PPB) Paperboard: Greeting cards, frozen food boxes, book
   covers
   METALS
   # 40 FE Steel
   #41 ALU Aluminium
   BIO-MATTER
   #50 FOR Wood
   #51 FOR Cork (bottle toppers, place mats, construction material)
   #60-#69 Textiles
   #70-79 Glass

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