Recycling

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"Recycle" redirects here. For the audio software by the same name, see ReCycle (program).
The international recycling symbol.
In New York City, people can be seen earning money by collecting recyclable materials and receiving the return deposit.

Recycling is the reprocessing of materials into new products. This is in contrast with reuse: collecting waste such as food containers to be cleaned, refilled and resold, or melted and changed into something else. Recycling prevents useful materials being landfilled or incinerated, reduces the consumption of raw materials, and normally requires less energy than virgin production. Commonly recycled materials include glass, paper, aluminium, asphalt, steel, textiles and plastic. These materials can be derived either from pre-consumer waste (materials used in manufacturing) or post-consumer waste (materials discarded by the consumer). Recycling is a key concept of modern waste management and is the third component of the waste hierarchy. To be recycled waste has to be sorted and separated into material types. Waste sorting is performed either by the consumer/waste producer 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 leaves materials for recycling at the front of their property, typicially in boxes or sacks to be collected by a recycling vehicle. Alternatively the householder may take the materials to recycling banks (sometimes described as a 'bring system') where materials are placed into recycling bins based on their material type.


History

Recycling bins in Aberystwyth, Wales. Bilingual with English and Welsh.

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 brickmaking. 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 occurances 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

One of the main benefits of recycling comes from reducing the amount of new material required. In theory, recycling allows a material to be continually reused for the same purpose, and in many cases this theory holds true, most notably in the recycling of metals and glass.

Since less raw material is required, recycling creates further benefits for materials where cost of the initial extraction or production is high—either economically, socially or environmentally. The recycling of aluminium, for example, saves 95% of the CO2 emissions—an environmentally harmful greenhouse gas—compared to refining new metal.

Concerns about limited resources such as raw materials and land space for disposal of waste have increased the importance of recycling. However maximum environmental benefit is gained by reducing the amount of waste produced, and reusing items in their current form, for example refilling bottles. All recycling techniques consume energy, for transportation and processing, and some also use considerable amounts of water. Both of these resources have an environmental impact which is why campaigners use the slogan Reduce, Reuse, Recycle to indicate the preferred order for waste management in the waste hierarchy.

Comparing recycling with normal extraction

Aluminium Recycling one kilogram of aluminium saves up to 8 kilograms of bauxite, four kilograms of chemical products and 14 kilowatt hours of electricity.

[1] [2]

It takes 20 times more energy to make aluminum from bauxite ore than using recycled aluminum.[3]
Glass A 20% reduction in emissions from glass furnaces and up to 32% reduction in energy usage. [citation needed] For every ton of recycled glass used, approx 315 kilos of Carbon dioxide and 1.2 tons of raw materials are spared. [4]
Paper A ton of paper from recycled material conserves about 7,000 gallons of water, 17-31 trees and 4,000 KWh of electricity.[5] 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.[5]

Drawbacks

A recyclables collection station in Oxford, England.

Paper can only be recycled a finite number of times due to the shortening of paper fibres making the material less versatile. Often it will be mixed with a quantity of virgin material. This is 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.

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 centralised facilities such as some advanced material recovery facilities of mechanical biological treatment systems for the separation of mixed wastes.

Recycling techniques

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

Shipbreaking

Main article: Shipbreaking

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 placed nearby 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.

Electronics disassembly and reclamation

Main article: Electronic waste
Abandoned monitor

Electronic devices, including audio-visual components (televisions, VCRs, stereo equipment), mobile phones and other hand-held devices, computer components, and gaming equipment, 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 synthesise further toxic byproducts.

In the United States, an estimated 70% of heavy metals in landfills come from discarded electronics.[6] Some regional governments are attempting to curtail the accumulation of electronics in landfills by passing laws obligating manufacturers and consumers to recycle these devices,[7] but because in many cases safe dismantlement of these devices in accordance with first world safety standards is unprofitable,[citation needed] 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.[8] [9]

Aluminium

Main article: Aluminium recycling
Recycling and rubbish bin in a German railway station.

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.

The environmental benefits of recycling aluminium are also enormous. Only around 5% of the CO2 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.[1]

In addition, an aluminium can is 100% recyclable. As a result of this, the same can can be reused an infinite number of times. Plus, every time it is recycled, it saves enough energy to watch television for about three hours (compared to mining and producing a new can).

Batteries

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.

Concrete

Main article: Concrete recycling

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.

Electrical equipment

Main article: Electronic waste

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.


Glass

Main article: Glass recycling

Glass bottles and jars are gathered via kerbside collection schemes and bottle banks, where the glass is 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 moulded into new jars or bottles. Glass cullet is also used in the construction industry for aggregate and glasphalt. Glasphalt is a road-laying material which comprises around 30% recycled glass. Glass can be recycled indefinitely as its structure does not deteriorate when reprocessed.

Biodegradable waste

Main article: Composting
Main article: Anaerobic digestion
Main article: Mechanical biological treatment

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 kerbside 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.

Paper

Main article: Paper recycling

Paper can be directly recycled or treated with other biodegradable wastes. In direct recycling it is separated into its component fibres in water, which creates a pulp slurry material. A cleaning process removes non-fibrous contaminants and if required, sodium hydroxide or sodium carbonate is used to de-ink the material. This fibre is then ready to be used to make new recycled paper. Paper is the main material that gets recycled in most countries.


Steel

Main article: Steel

Steel is the worlds most recycled material, and one of the easiest materials to recycle, as it can be separated magnetically from the wastestream. 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).[10] 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.[11]

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. 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.

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.

Recycling by region

Recycling in the United States

Main article: Recycling in the United States

Recycling in Canada

Main article: Recycling in Canada

Criticism

Main article: Recycling Criticism

Many areas of recycling have come under criticism or scrutiny. Most notably the claimed benefits that recycling saves energy, reduces greenhouse gas emissions and creates jobs.

See also

Types of recycling
General topics

References

  1. ^ a b Aluminium Recycling Facts, International Aluminium Institute link
  2. ^ Metals - aluminium and steel recycling information sheet, Waste Watch link
  3. ^ Benefits of Recycling, Ohio Department of Natural Resources link
  4. ^ Glass recycling information sheet, Waste Watch link
  5. ^ a b Recycling Paper & Glass, U.S Department of Energy Kid's Page link
  6. ^ Poison PCs/Toxic TVs Executive Summary, Silicon Valley Toxic Corporation link
  7. ^ California to electronics industry: No toxins for you! by Nate Anderson, February 24, 2006 link
  8. ^ Activists Push for Safer E-Recycling link
  9. ^ Computer age leftovers, Denver Post link
  10. ^ Sustainable Development and Steel, Canadian Institute of Steel Construction link
  11. ^ Steel: The Foundation of a Sustainable Future, Sustainability Report of the World Steel Industry 2005 link (PDF)

External links

UK links

International links



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