Recycling

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Recycling :: Recycling_Equipment :: Recycling_Information :: Recycling_Machinery

Recycling is the reprocessing of used materials that would otherwise become waste in order to break them down and remake them into new products. This is in contrast with reuse: collecting waste such as food containers to be cleaned, refilled and resold. Recycling prevents the waste being sent to a landfill or incinerator, and reduces the consumption of new raw materials. Commonly recycled materials include glass, paper, aluminium, asphalt, steel and textiles. 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.

In theory, recycling allows a continuing reuse of materials for the same purpose. In most cases this is true, especially with metals and glass. In the case of fiber, recycling most often extends the useful life of this material, but in a less-versatile form. This is referred to as downcycling. For example, when paper is recycled, the fibers shorten, making it less useful for high grade papers. Other materials can suffer from contamination, making them unsuitable for food packaging.

Environmental impact

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.^*

History

Resource shortages caused by wartime has been a driver for recycling. Massive government promotion campaigns were carried out in World War II in every country involved in the war, urging citizens to conserve metals and fibre. In America, the process of recycling was given 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 kerbside 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.

Methods

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

Aluminium

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

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.

Electrical equipment

Glass

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.

Organic waste

Organic 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

Paper is separated into its component fibers in water, which creates a pulp slurry material. A cleaning process removes nonfibrous 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.

Plastic

Textiles

Workers sort collected textiles to separate them into good quality clothing and shoes which can be reused, worn or damaged textiles which can be sorted into grades to make industrial wiping cloths and for use in paper manufacture, and 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.

US issues

A number of U.S. states, such as California, Hawaii, Oregon, Connecticut, Delaware, Maine, Vermont, Massachusetts, Iowa, Michigan and New York have passed laws that establish deposits or refund values on beverage containers in order to promote recycling. Most are five cents per can or bottle. Michigan's deposit is 10 cents. Some cities, such as New York City and Seattle, have created laws that enforce fines upon citizens who throw away certain recyclable materials.

State support for recycling may be more expensive than alternatives such as landfill; recycling efforts in New York City in the USA cost $57 million per year.¹ Environmentalists argue that the benefits to society from recycling compensate for any difference in cost.

Public awareness

In 1987, a barge called the Mobro 4000, containing a little over 3,000 tons of garbage departed from Islip, New York to deposit its load of garbage in Morehead City, North Carolina. However, before it reached its destination, rumors that it contained medical waste caused officials at Morehead City to deny the barge permission to unload its garbage. As a result, the barge traveled down the East Coast of the United States searching for a place to unload, eventually being denied in Mexico and Belize. The barge finally returned to Islip, where the trash was incinerated after a brief legal battle. The barge's journey became a small media event. According to the Federal Reserve Bank of Boston Kelly Ferguson (editor of a pulp and paper industry newsletter) John Tierney [http://www.williams.edu/HistSci/curriculum/101/garbage.html" target="_blank" >^*, media coverage of the Mobro 4000 led to the false public perception that American landfills were nearly out of space. They say that this perception led to increased public interest in programs to recycle household goods.

References

Logomasini, Angela. 2002. Forced Recycling Is a Waste The Wall Street Journal. March 19 2002.

External links

Recycle-more UK based recycling information site
Video archive of BBC footage - an investigation into 3rd world dumps for western rubbish
Ill effects of RFID Tags on recycling
A Recycling Revolution - recycling information
Earth 911 - USA recycling information
About.com - 10 Ideas for Waste Recycling and Reduction
New York Times Magazine: Recycling is Garbage (registration required)
ReReRe Guide Guide to Recycling, reducing and reusing products
Scenarios and Strategies for Extended Producer Responsibility (PDF) From the Swedish Morphological Society
Eight Great Myths of Recycling A paper by Daniel K. Benjamin of the Property, Environment, and Research Center detailing the reasons why some recycling programs have proved costly and ineffective
Is Recycling Good For The Environment? Allan L. Griff, Consulting Engineer, Plastic Extrusion Consultant and Educator
Swedes trash myth of refuse recycling
University of Massachusetts, Amherst - Environmental benefits of recycling
GreenGuardian.com - Minnesota based recycling information resource

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