Recycling is the reprocessing of old materials into new products, with the aims of preventing the waste of potentially useful materials, reducing the consumption of fresh raw materials, reducing energy usage, reducing air (from incineration) and water (from landfilling) pollution by reducing the need for "conventional" waste disposal, and lowering greenhouse gas emissions as compared to virgin production. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός Incineration is a waste treatment technology that involves the Combustion of organic materials and/or substances For other uses see Water treatment and Land reclamation. A landfill, also known as a dump (and historically as Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared ^[1][2] Recycling is a key concept of modern waste management and is the third component of the "Reduce, Reuse, Recycle" waste hierarchy, though colloquial usage of "recycling" can also include "reuse". Waste management is the collection Transport, processing, Recycling or disposal of Waste materials The waste hierarchy refers to the 3 Rs of reduce, Reuse and recycle, which classify Waste management strategies according to their desirability

"Recyclable materials" or "recyclables", may originate from home, business or industry. They include glass, paper, metal, textiles and plastics. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many Paper is thin material mainly used for writing upon printing upon or packaging The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across A textile is a flexible material comprised of a network of natural or artificial Fibres often referred to as thread or Yarn. Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products Though analogus, the composting of biodegradable waste—such as food or garden waste—is not typically considered recycling. Biodegradable waste is a Type of waste, typically originating from Plant or Animal sources which may be broken down by other living organisms Food waste, kitchen waste, or garbage ( North American English) is any form of Waste derived from food materials Green waste is Biodegradable waste that can be comprised of Garden or Park waste such as Grass or Flower cuttings and hedge ^[2] These materials are either brought to a collection centre or picked-up from the curbside; and sorted , cleaned and reprocessed into new products bound for manufacturing.

To judge the environmental benefits of recycling, the cost of this entire process must be compared to the cost of virgin extraction. In order for recycling to be economically viable, there usually must be a steady supply of recyclates and constant demand for the reprocessed goods; both of which can be stimulated through government legislation. Legislation (or " Statutory law " is law which has been promulgated (or " Enacted quot by a Legislature or other Governing ^[2]

Meanwhile, critics claim that government mandated recycling wastes more resources than it saves. These critics claim that free market prices, and not politicians, are the most accurate way to determine whether or not any particular type of garbage should be recycled. According to these critics, whenever recycling truly does save resources, the private sector will voluntarily offer people money for their garbage. ^[3][4]

History

Early recycling

Recycling has been a common practice for most of human history, with recorded advocates as far back as Plato in 400 BC. Biography Early life Birth and family Plato was born in Athens Greece The 4th century BC started the first day of 400 BC and ended the last day of 301 BC. During periods when resources were scarce, archaeological studies of ancient waste dumps show less household waste (such as ash, broken tools and pottery)—implying more waste was being recycled in the absence of new material. ^[5]

In pre-industrial times, there is evidence of scrap bronze and other metals being collected in Europe and melted down for perpetual reuse,^[6] and in Britain dust and ash from wood and coal fires was downcycled as a base material in brick making. Pre-industrial society refers to specific social attributes and forms of political and cultural organization that were prevalent before the advent of the Industrial Revolution Downcycling is the Recycling of a material into a material of lesser quality 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 densely-populated areas. ^[5]

Wartime recycling

Resource shortages caused by the world wars, and other such world-changing occurrences greatly encouraged recycling. A world war is a War affecting the majority of the world's most powerful and populous nations 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 fiber, as a matter of significant patriotic importance. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including 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.

Post-war recycling

The next big investment in recycling occurred in the 1970s, due to rising energy costs. Recycling aluminum 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. ^[7]

In 1987, the Mobro 4000 barge hauled garbage from New York to North Carolina; where it was denied. The Mobro 4000 is a Barge made famous in 1987 for hauling the same load of Trash along the east coast of North America from New York New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous North Carolina ( is a state located on the Atlantic Seaboard in the southeastern United States It was then sent to Belize; where it was denied as well. Belize (bəˈliːz formerly British Honduras, is a country in Central America. Finally, the barge returned to New York and the garbage was incinerated. The incident led to heated discussions in the media about waste disposal and recycling. The incident is often referred to as igniting the recycling "hysteria" of the 1990s. ^[6]

Fiscal and environmental economics

There is much debate over whether recycling is economically feasible. Economics is the social science that studies the production distribution, and consumption of goods and services. Advocates of recycling argue that judging the process on financial issues alone is not enough. They claim that the environmental benefits, energy savings, waste reduction and raw material conservation must also be considered. See also Nature The natural environment, commonly referred to simply as the environment, is a terminology that is comprised of all living and The use of energy has been a key in the development of the human society by helping it to control and adapt to the environment. WASTE is a Peer-to-peer and Friend-to-friend protocol and software application developed by Justin Frankel at Nullsoft in 2003 that features Materials are physical Substances used as inputs to production or Manufacturing. In order to make such non-fiscal benefits economically relevant, advocates have pushed for legislative action to increase the demand for recycled materials. Law is a system of rules enforced through a set of Institutions used as an instrument to underpin civil obedience politics economics and society Supply and demand is an Economic model describing effects on price and quantity in a Market. ^[2]

Opponents counter that recycling is not reasonable if it is more costly than disposal and new virgin production. Any government incentives to support recycling, they claim, would not result in the most efficient use of resources. A resource is any physical or virtual entity of limited availability or anything used to help one earn a living John Tierney, writing in 1996 for the New York Times, claimed that New York's recycling program would cost $3000 per ton of recyclates if the public were paid for their time spent sorting and cleaning. ^[8] Michael Munger, the Chair of Political Science at Duke University, has argued that the financial costs of recycling some materials outweigh the environmental benefits, and that the benefits do not compensate for the extra effort recycling requires. Duke University is a private Research University located in Durham, North Carolina, United States. ^[9] For example, though recycling might make economic sense in a densely populated area where virgin materials are scarce and disposal costs high, legislated recycling in other situations would only bring unnecessary economic hardship. ^[2]

From these debates it has become clear that certain requirements must be met in order for recycling to be economically feasible and environmentally effective. These include an adequate source of recyclates, a system to extract those recyclates from the waste stream, a nearby factory capable of reprocessing the recyclates, and a potential demand for the recycled products. There are many Waste streams consisting of a number of waste types. A factory (previously manufactory) or manufacturing plant is an industrial Building where workers manufacture goods These last two requirements are often overlooked—without both an industrial market for production using the collected materials and a consumer market for the manufactured goods, recycling is incomplete and in fact only "collection". Sao Paulo Stock Exchangejpg|thumb| Virtual market arena where buyer and seller are not present and trade via intemediates and electronical information ^[2]

Environmental effects of recycling^[10]

Material	Energy Savings	Air Pollution Savings
Aluminium	95%[2][7]	95%[2][11]
Cardboard	24%	—
Glass	5-30%	20%
Paper	40%[7]	73%
Plastics	70%[7]	—
Steel	60%[6]	—

Determining the environmental effect of recycling is non-trivial. Environmental economics is a subfield of Economics concerned with environmental issues In order to decide whether the recycling of a certain material has environmental benefit, the environmental impact of recycling must be determined and then compared to the effect of virgin production. First, one must look at the environmental impact of collection itself. If a second waste collection vehicle must cover an entire city to collect material to be recycled, this will have an environmental effect. A waste collection vehicle (WCV or colloquially called a 'Garbage Truck' 'Dustcart' or 'Dustbin lorry' is a Truck specially designed to pick up smaller quantities of Next, the recyclates must be washed and sorted, which requires both water for cleaning and energy to drive the sorting apparatus. Water resources are sources of Water that are useful or potentially useful to Humans Uses of water include Agricultural, industrial, Household Then there are the environmental costs of transporting the recyclates to the reprocessing plant and the subsequent shipping of the reprocessed materials to new manufacturers. Transport or transportation is the movement of people and goods from one place to another Finally, the reprocessing itself must be considered, as this stage can require large amounts of energy and water, and may result in significant air pollution. Air pollution is the human introduction into the atmosphere of Chemicals Particulate matter, or Biological materials that cause harm or discomfort ^[2]

The direct benefits of recycling must also be factored into the environmental calculation. Recycling helps to conserve natural resources, which is especially important with non-renewable resources such as aluminium and other metals; it diverts waste which would otherwise end up incinerated or dumped in landfills and lead to greenhouse-gas emissions; and it avoids the environmentally damaging process of mining or harvesting new virgin materials. Incineration is a waste treatment technology that involves the Combustion of organic materials and/or substances For other uses see Water treatment and Land reclamation. A landfill, also known as a dump (and historically as Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body In Agriculture, the harvest is the process of Gathering mature crops from the fields Reaping is the cutting of Grain ^[6]

Once the environmental costs of both virgin production plus "conventional" waste disposal, and recycling are known; the two processes can be compared. Even at this stage, it can be difficult to determine which is most beneficial, as there will often be a lot of estimation involved in the cost calculation. Estimation is the calculated Approximation of a result which is usable even if Input data may be incomplete or uncertain. Ultimately, however, the final choice may come down to an apparent trade-off; for example virgin production may use more energy, while recycling may require a larger supply of water. A trade-off (or tradeoff) is a situation that involves losing one quality or aspect of something in return for gaining another quality or aspect

Despite these complexities, a study conducted by the Technical University of Denmark found that in 83% of cases, recycling is the most efficient method to dispose of household waste. The Technical University of Denmark ( Danish: Danmarks Tekniske Universitet, DTU was founded in 1829 as the 'College of Advanced Technology' (Danish Den ^{[6] [7]} The United States Environmental Protection Agency (EPA) has also concluded in favour of recycling, saying that recycling efforts reduced the country's carbon emissions by a net 49 metric tonnes in 2005. Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared This article is about the tonne or metric ton For other tons see Ton. ^[6] In the United Kingdom, the Waste and Resources Action Programme stated that Great Britain's recycling efforts reduce CO₂ emissions by 10-15 tonnes a year. The Waste & Resource Action Plan, WRAP, is a Not-for-profit Company created in 2000 as part of the UK Government's waste strategies. ^[6]

On the other side of the debate, economist Steven Landsburg has claimed that recycling is more costly than mining virgin materials, saying that the only savings are in reduced landfill usage. An economist is an expert in the Social science of Economics. Steven E Landsburg (born 1954 is an American professor of economics at the University of Rochester in Rochester, New York. He has also claimed that paper recycling leads to fewer forests, as paper manufacturers then need to maintain less woodland. ^[12] John Tierney's extensive New York Times article, titled "Recycling is Garbage", was also highly critical of recycling, saying "the simplest and cheapest option is usually to bury garbage in an environmentally safe landfill", and claiming that "recycling may be the most wasteful activity in modern America: a waste of time and money, a waste of human and natural resources". ^[8] Richard A. Denison and John F. Ruston, members of the Environmental Defense Fund, published a rebuttal to Tierney's article, claiming it to be "gravely inaccurate" and that "[Tierney] unquestioningly repeats the claims of a group of think tanks and consultants. Environmental Defense Fund or EDF (formerly known as Environmental Defense) is a US -based nonprofit environmental advocacy group. . . that have strong ideological objections to recycling". ^[13]

Import and export of recyclates

The value of recyclates can be seen by the fact that certain countries have begun to import the unprocessed materials. Some have complained that the ultimate fate of recyclates sold to another country is unknown and they may end up in landfill instead of reprocessed. According to one report, in America, 50-80% of computers destined for recycling are actually not recycled ^[14]. However, Pieter van Beukering, an economist specialising in waste imports of China and India, believes that it is unlikely that bought materials would merely be dumped in landfill: he also claims that the import of recyclates allows for large-scale reprocessing, improving both the fiscal and environmental return through economies of scale. Talk People's Republic of China) PEOPLE'S REPUBLIC OF CHINA ARTICLE GUIDELINES India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country ^[6]

Unfortunately, there are reports of illegal-waste imports to China being dismantled and recycled solely for monetary gain, without consideration for workers' health or environmental damage. Though the Chinese government has banned these practices, it has not been able to eradicate them completely, nor estimate the amount of illegal recycling still occurring. ^[6]

Certain regions have difficulty using or exporting as much of a material as they recycle. This problem is most prevalent with glass: both Britain and the US import large quantities of wine bottled in green glass. Though much of this glass is sent to be recycled, outside the American Midwest there is not enough wine production to use all of the reprocessed material. The extra must be downcycled into building materials or re-inserted into the regular waste stream. ^[6][2]

Similarly, the northwestern United States has difficultly finding markets for recycled newspaper, given the large number of pulp mills in the region as well as the proximity to Asian markets. See also Pacific Northwest The Northwestern United States comprise the northwestern states up to the western Great Plains regions of the United States A pulp mill is a manufacturing facility that converts wood chips or other plant fiber source into a thick fiber board which can be shipped to a Paper mill for further In other areas of the US, however, demand for used newsprint has seen wide fluctuation. ^[2]

Criticism

Main article: Recycling criticism

In an article in The New York Times, John Tierney claimed that government mandated recycling wastes more resources than it saves. ^[15] Some highlights from the article:

• In cases where recycling truly does save resources, such as with large scraps of aluminum, this will be reflected in market prices, and voluntary recycling will take place. Thus, there is no need for the government to mandate it.
• Tree farmers plant more trees than they cut down.
• Government mandated recycling is more expensive than putting the garbage into landfills, which means that this recycling uses up more resources than it saves.
• Some small towns with landfills are happy to import garbage from other cities and states because it provides jobs and tax revenue.
• Today's modern landfills are much cleaner and safer, and much less likely to leak and pollute than the landfills of the past.
• Modern landfills often collect the methane produced by the decomposition of the biological wastes (which would have otherwise escaped into the atmosphere adding to global warming) and use the gas as fuel to produce electricity for the surrounding communities.
• Regarding the claim that the U. S. is running out of landfill space, Tierney wrote, "A. Clark Wiseman, an economist at Gonzaga University in Spokane, Wash. , has calculated that if Americans keep generating garbage at current rates for 1,000 years, and if all their garbage is put in a landfill 100 yards deep, by the year 3000 this national garbage heap will fill a square piece of land 35 miles on each side. This doesn't seem a huge imposition in a country the size of America. The garbage would occupy only 5 percent of the area needed for the national array of solar panels proposed by environmentalists. The millennial landfill would fit on one-tenth of 1 percent of the range land now available for grazing in the continental United States. And if it still pains you to think of depriving posterity of that 35-mile square, remember that the loss will be only temporary. Eventually, like previous landfills, the mounds of trash will be covered with grass and become a minuscule addition to the nation's 150,000 square miles of parkland. "

In a 2002 article for The Heartland Institute, Jerry Taylor, director of natural resource studies at the Cato Institute, wrote, "If it costs X to deliver newly manufactured plastic to the market, for example, but it costs 10X to deliver reused plastic to the market, we can conclude the resources required to recycle plastic are 10 times more scarce than the resources required to make plastic from scratch. The Cato Institute is a Libertarian Think tank headquartered in Washington D And because recycling is supposed to be about the conservation of resources, mandating recycling under those circumstances will do more harm than good. " ^[16]

The city of Santa Clarita, California was paying $28 per ton to put garbage into a landfill. Santa Clarita is the fourth largest city in Los Angeles County, California, United States. The city then adopted a diaper recycling program that cost $1,800 per ton. ^[17]

All recycling techniques consume energy for transportation and processing and some also use considerable amounts of water, although recycling processes seldom amount to the level of resource use associated with raw materials processing. ^[18]

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 and mechanical biological treatment systems for the separation of mixed wastes. A materials recovery facility or materials reclamation facility ( MRF -- pronounced "murf" is a specialized plant that receives separates and prepares recyclable A mechanical biological treatment system is a form of waste processing facility that combines a sorting facility with a form of biological treatment such as Composting or It has been calculated that collecting waste and disposing it in a landfill is about $60 a ton opposed to separate collecting and taking it to be recycled costs $150 a ton. ^[19]

Recycled materials also sometimes cost more financially than their non-recycled versions. This is not universal to every recycled product, but it does occur. ^[20]

Negative consequences from mercury recycling have been cited by The Wall Street Journal. ^[21] The article traces mercury recovered from American recycling programs into sales of mercury for alluvial mining activities in Brazil. Alluvium (from the Latin, alluvius, from alluere, "to wash against" is Soil or Sediments deposited by a river or other running During the autumn of 2006, the European Union banned the export of liquid mercury, and a life-cycle analysis prior to institution of recycling programs may reduce the risk of unintended environmental consequences. The European Union ( EU) is a political and economic union of twenty-seven member states, located primarily in

Michael Munger, the Chair of Political Science at Duke University, argued that the financial costs of recycling some materials outweigh the environmental benefits, and that the environmental benefits of recycling do not compensate for the extra effort it may require. Duke University is a private Research University located in Durham, North Carolina, United States. In a 2007 article, he wrote, ". . . if recycling is more expensive than using new materials, it can't possibly be efficient. . . There is a simple test for determining whether something is a resource. . . or just garbage. . . If someone will pay you for the item, it's a resource. . . But if you have to pay someone to take the item away. . . then the item is garbage. " ^[22]

In the US, recycling facilities currently generate estimated revenues of $2,981 million a year. Growth has exceeded 7 percent per year for the past five years (from 2003 to 2008) due to rising waste volumes and increasing recyclable commodity prices. New initiatives can change the industry. For example in California, and New York moves to raise the requirements for the set amount of waste to be diverted from the waste stream from 50 percent to 75 percent can produce healthy profits for companies that collect and process recyclables. ^[23]

Legislation

Supply

In order for a recycling program to work, having a large, stable supply of recyclable material is crucial. Supply and demand is an Economic model describing effects on price and quantity in a Market. Three legislative options have been used to create such a supply: mandatory recycling collection, container deposit legislation, and refuse bans. Container deposit legislation are Laws passed by city state provincial or national governments that require that a deposit on carbonated, milk water or Alcoholic Mandatory collection laws set recycling targets for cities to aim for, usually in the form that a certain percentage of a material must be diverted from the city's waste stream by a target date. The city is then responsible for working to meet this target. ^[2]

Container deposit legislation involves offering a refund for the return of certain containers, typically glass, plastic, and metal. When a product in such a container is purchased, a small surcharge is added to the price. This surcharge can be reclaimed by the consumer if the container is returned to a collection point. These programs have been very successful, often resulting in an 80% recycling rate. Despite such good results, the shift in collection costs from local government to industry and consumers has created strong opposition to the creation of such programs in some areas. ^[2]

A third method of increase supply of recyclates is to ban the disposal of certain materials as waste, often including used oil, old batteries, tires and garden waste. A ban (derived from Banishment) is generally any Decree that prohibits something One aim of this method is to create a viable economy for proper disposal of banned products. Care must be taken that enough of these recycling services exist, or such bans simply lead to increased illegal dumping. A service is the non-material equivalent of a good. A service provision is an economic activity that does not result in Ownership, and this is what differentiates Fly-tipping or dumping is a British term for illegally dumping Waste somewhere other than an authorised Landfill. ^[2]

Government mandated "demand"

Legislation has also been used to increase and maintain a "demand" for recycled materials. Four methods of such legislation exist: minimum recycled content mandates, utilisation rates, procurement policies, recycled product labelling. Procurement is the acquisition of goods and/or services at the best possible Total cost of ownership, in the right quantity and quality at the right time in the right place Mandatory labelling or labeling (see Spelling differences) is the requirement of consumer products to state their ingredients or components ^[2]

Both minimum recycled content mandates and utilisation rates increase "demand" directly by forcing manufacturers to include recycling in their operations. Content mandates specify that a certain percentage of a new product must consist of recycled material. Utilisation rates are a more flexible option: industries are permitted to meet the recycling targets at any point of their operation or even contract recycling out in exchange for tradeable credits. Trade is the willing exchange of goods, services, or both Trade is also called Commerce. Opponents to both of these methods point to the large increase in reporting requirements they impose, and claim that they rob industry of necessary flexibility. ^[2][24]

Governments have used their own purchasing power to increase recycling demand through what are called "procurement policies". For the government of parliamentary systems see Executive (government. Purchasing power is the amount of value of a good/services compared to the amount paid with a Currency. These policies are either "set-asides", which earmark a certain amount of spending solely towards recycled products, or "price preference" programs which provide a larger budget when recycled items are purchased. A government Budget is a legal document that is often passed by the Legislature, and approved by the Chief executive -or president Additional regulations can target specific cases: in the US, for example, the Environmental Protection Agency mandates the purchase of oil, paper, tires and building insulation from recycled or re-refined sources whenever possible. The United States of America —commonly referred to as the ^[2]

The final government regulation towards increased demand is recycled product labeling. When producers are required to label their packaging with amount of recycled material in the product (including the packaging), consumers are better able to make educated choices. Consumers with sufficient buying power can then choose more environmentally conscious options, prompt producers to increase the amount of recycled material in their products, and indirectly increase demand. Purchasing power is the amount of value of a good/services compared to the amount paid with a Currency. Standardised recycling labelling can also have a positive affect on supply of recyclates if the labelling includes information on how and where the product can be recycled. ^[2]

Collection

A number of different systems have been implemented to collect recyclates from the general waste stream. These systems tend to lie along the spectrum of trade-off between public convenience and government ease and expense. The three main categories of collection are "drop-off centres", "buy-back centres" and "curbside collection". ^[2]

Drop-off centres require the waste producer carry the recyclates to a central location, either a installed or mobile collection station or the reprocessing plant itself. They are the easiest type of collection to establish, but suffer from low and unpredictable throughput. Buy-back centres differ in that the cleaned recyclates are purchased, thus providing an clear incentive for use and creating a stable supply. The post-processed material can then be sold on, hopefully creating a profit. Unfortunately government subsidies are necessary to make buy-back centres a viable enterprise, as according to the United States Nation Solid Wastes Management Association it costs on average US$50 to process a ton of material, which can only be resold for US$30. ^[2]

Curbside collection

Curbside collection encompasses many subtly different systems, which differ mostly on where in the process the recyclates are sorted and cleaned. The main categories are "mixed waste collection", "commingled recyclables" and "source separation". ^[2]

At one end of the spectrum is "mixed waste collection", in which all recyclates are collected mixed in with the rest of the waste, and the desired material is then sorted out and cleaned at a central sorting facility. This results in a large amount of recyclable waste, paper especially, being too soiled to reprocess, but has advantages as well: the city need not pay for a separate collection of recyclates and no public education is needed. Any changes to which materials are recyclable is easy to accommodate as all sorting happens in a central location. ^[2]

In a "Commingled" or "single-stream" system, all recyclables for collection are mixed but kept separate from other waste. This greatly reduces the need for post-collection cleaning but does require public education on what materials are recyclable. Public education is education mandated for or offered to the children of the general public by the Government, whether national regional or local provided by an institution ^[2][6]

"Source separation" is the other extreme, where each material is cleaned and sorted prior to collection. This method requires the least post-collection sorting and produces the purest recyclates, but incurs additional operating costs for collection of each separate material. operating cost are the recurring expenses which are related to the operation of a business or to the operation of a device component piece of equipment or facility An extensive public education program is also required, which must be successful if recyclate contamination is to be avoided. ^[2]

Source separation used to be the preferred method due to the high sorting costs incurred by commingled collection. Advances in sorting technology (see "sorting" below), however, have lowered this overhead substantially—many areas which had developed source separation programs have since switched to comingled collection. Recycling involves processing used materials into new products in order to prevent the waste of potentially useful materials reduce the consumption of fresh raw materials reduce ^[6]

Sorting

Once commingled recyclates are collected and delivered to a central collection facility, the different types of materials must be sorted. A materials recovery facility or materials reclamation facility ( MRF -- pronounced "murf" is a specialized plant that receives separates and prepares recyclable This is done in a series of stages, many of which involve automated processes such that a truck-load of material can be fully sorted in less than an hour. ^[6]

Initially, the commingled recyclates are removed from the collection vehicle and placed on a conveyor belt spread out in a single layer. Large pieces of cardboard and plastic bags are removed by hand at this stage, as they can cause later machinery to jam. Cardboard is a generic non-specific term for a heavy duty Paper based product A plastic bag or pouch is a type of flexible Packaging made of thin flexible plastic film ^[6]

Next, automated machinery separates the recyclates by weight, splitting lighter paper and plastic from heavier glass and metal. Cardboard is removed from the mixed paper and the most common types of plastic (PET and HDPE) are collected. Uses PET can be semi-rigid to rigid depending on its thickness and is very lightweight High-Density Polyethylene ( HDPE) or PolyEthylene High-Density ( PEHD) is a Polyethylene Thermoplastic made from Petroleum This separation is usually done by hand, but has become automated in some sorting centres: a spectroscopic scanner is used to differentiate between different types of paper and plastic based on the absorbed wavelengths, and subsequently divert each material into the proper collection channel. Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ ^[6]

Strong magnets are used to separate out ferrous metals (tin-plated or steel cans), while non-ferrous metals are ejected by "magnetic eddy currents". Ferrous, in the chemical science realm indicates a bivalent iron compound (+2 oxidation state (as opposed to Ferric, which indicates a trivalent iron compound (+3 oxidation A tin can, also called a tin (especially in British English) or a can, is an air-tight container for the distribution or storage of Ferrous, in the chemical science realm indicates a bivalent iron compound (+2 oxidation state (as opposed to Ferric, which indicates a trivalent iron compound (+3 oxidation An eddy current (also known as Foucault current) is an electrical phenomenon discovered by French physicist Léon Foucault in A rotating magnetic field induces an electric current around the aluminum cans, which in turn creates a magnetic eddy current inside the cans. In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges This magnetic eddy current is repulsed by the large magnetic field, and the cans are ejected from the rest of the recyclate stream. ^[6]

Finally, glass must be sorted by hand based on its color: brown, amber, green or clear. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many ^[6]

Common recyclables

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

Aggregates and 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. When structures made of Concrete are to be demolished concrete recycling is an increasingly common method of disposing of the rubble Aggregate is the component of a Composite material used to resist compressive stress A crusher is a Machine designed to reduce large Solid Material Objects into a smaller volume or smaller pieces 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. This reduces the need for other rocks to be dug up, which in turn saves trees and habitats. ^[25]

Batteries

Main article: Battery recycling

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. Battery recycling is a Recycling activity that aims to reduce the number of batteries being disposed as Municipal solid waste. In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy Battery recycling is a Recycling activity that aims to reduce the number of batteries being disposed as Municipal solid waste. Additionally, older batteries contain mercury and cadmium, harmful materials which must be handled with care. Because of their potential environmental damage, proper disposal of used batteries is required by law in many areas. Unfortunately, this mandate has been difficult to enforce. ^[26]

Lead-acid batteries, like those used in automobiles, are relatively easy to recycle and many regions have legislation requiring vendors to accept used products. In the United States, the recycling rate is 90%, with new batteries containing up to 80% recycled material. ^[26]

Biodegradable waste

Main article: Composting

Kitchen, garden and other green waste can be recycled into useful material by composting. Composting is the Aerobic decomposition of Biodegradable Organic matter, producing Compost. Green waste is Biodegradable waste that can be comprised of Garden or Park waste such as Grass or Flower cuttings and hedge Composting is the Aerobic decomposition of Biodegradable Organic matter, producing Compost. This process allows natural aerobic bacteria to break down the waste into fertile topsoil. An aerobic organism or aerobe is an Organism that has an Oxygen based Metabolism. Topsoil is the upper outermost layer of soil usually the top 2 to 8 inches Much composting is done on a household scale, but municipal green-waste collection programs also exist. These programs can supplement their funding by selling the topsoil produced.

Electronics disassembly and reclamation

Main article: Computer recycling

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. Computer recycling refers to recycling or reuse of a Computer or Electronic waste. A computer is a Machine that manipulates data according to a list of instructions. The recycling process works by mechanically separating the metals, plastics and circuit boards contained in the appliance. A printed circuit board, or PCB, is used to mechanically support and electrically connect Electronic components using conductive pathways or traces When this is done on a large scale at an electronic waste recycling plant, component recovery can be achieved in a cost-effective manner.

Ferrous metals

Main article: Steel recycling

Iron and steel are the world's most recycled materials, and among the easiest materials to reprocess, as they can be separated magnetically from the waste stream. Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 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). ^[27] 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. ^[28]

Non-ferrous metals

Main article: Aluminium recycling

Aluminium is shredded and ground into small pieces or crushed into bales. Aluminium recycling is the process by which Scrap Aluminium can be reused in products after its initial production WikipediaNaming These pieces or bales 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. This process does not produce any change in the metal, so aluminium can be recycled indefinitely.

Recycling aluminium saves 95% of the energy cost of processing new aluminium. ^[7] This is because the temperature necessary for melting recycled, nearly pure, aluminium is 600 °C, while to extract mined aluminium from its ore requires 900 °C. To reach this higher temperature, much more energy is needed, leading to the high environmental benefits of aluminium recycling. ^[11]

Glass

Main article: Glass recycling

Glass bottles and jars are gathered via curbside collection schemes and bottle banks, where the glass may be sorted into color categories. Garbage Collection redirects here For the topic as related to computing see Garbage collection (computer science Waste collection is the component of Glass recycling is the process of turning Waste Glass into usable products 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. Glassphalt (also spelled "glasphalt" is a variety of Asphalt that uses crushed Glass. Glass can be recycled indefinitely as its structure does not deteriorate when reprocessed.

Paper

Main article: Paper recycling

Paper can be recycled by reducing it to pulp and combing it with pulp from newly harvested wood. Paper recycling is the process of recovering waste Paper and remaking it into new paper products As the recycling process causes the paper fibres to breakdown, each time paper is recycled its quality decreases. This means that either a higher percentage of new fibres must be added, or the paper downcycled into lower quality products. Any writing or colouration of the paper must first be removed by deinking, which also removes fillers, clays, and fiber fragments. ^[29]

Almost all paper can be recycled today, but some types are harder to recycle than others. 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. Gift wrap paper also cannot be recycled due to the its already low quality. ^[29]

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. Most of the clay is removed from the recycled pulp as sludge which must be disposed. If the coated paper is 20% by weight clay, then each ton of glossy paper produces more than 200 kg of sludge and less than 800 kg of fiber. ^[29]

Plastic

Main article: Plastic recycling

Plastic recycling is the process of recovering scrap or waste plastics and reprocessing the material into useful products. Plastic recycling is the process of Recovering scrap or waste Plastics and reprocessing the material into useful products sometimes completely different from their 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. The symbols in the table below belong to the SPI resin identification coding system, developed by the Society of the Plastics Industry in 1988 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.

Textiles

Main article: Textile recycling

When considering textile recycling one must understand what the material consists of. Textile recycling is the method of reusing or reprocessing used clothing fibrous material and clothing scraps from the manufacturing process 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. A waste picker, or a scavenger, is a person who picks out Recyclable elements from mixed waste wherever it may be temporarily accessible or disposed of. There is a trend of moving these facilities from developed countries to developing countries either for charity or sold at a cheaper price. ^[30] Many international organisations collect used textiles from developed countries as a donation to those third world countries. This recycling practise is encouraged because it helps to reduce unwanted waste while providing clothings to the needies. ^[31] Damaged textiles are further sorted into grades to make industrial wiping cloths and for use in paper manufacture or material suitable for fibre reclamation and filling products. If textile reprocessors receive wet or soiled clothes however, these may still be disposed of in a landfill, as the washing and drying facilities are not present at sorting units. ^[32]

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.

Timber

Main article: Timber recycling

Recycling timber has become popular due to its image as an environmentally friendly product, with consumers commonly believing that by purchasing recycled wood the demand for green timber will fall and ultimately benefit the environment. Recycling timber is the process of turning Waste Timber into usable products Greenpeace also view recycled timber as an environmentally friendly product, citing it as the most preferable timber source on their website. The arrival of recycled timber as a construction product has been important in both raising industry and consumer awareness towards deforestation and promoting timber mills to adopt more environmentally friendly practices. ^[33]

Wood recycling is a subject which has in recent years taken an ever greater role in our lives. The problem, however, is that although many local authorities like the idea of recycling, they do not fully support it. One of the countless examples, which has been in the news is the concept of actually recycling wood which is growing in the cities. Namely, recycling timber, trees and other sources. ^[34]

Other Techniques

Several other materials are also commonly recycled, frequently at an industrial level.

Ship breaking is one example that has associated environmental, health, and safety risks for the area where the operation takes place; balancing all these considerations is an environmental justice problem. Ship breaking or ship demolition is a type of Recycling involving the breaking up of Ships for Scrap. Environmental justice (EJ is the confluence of social and environmental movements which deals with the inequitable environmental burden born by groups such as racial minorities women

Tire recycling is also common. Tire recycling is the process of Recycling vehicles Tires (or tyres that are no longer suitable for use on vehicles due to wear or irreparable damage (such as punctures Used tires can be added to asphalt for producing road surfaces or to make rubber mulch used on playgrounds for safety. Asphalt ( is a sticky black and highly viscous liquid or semi-solid that is present in most crude Petroleums and in some natural deposits sometimes termed asphaltum Rubber mulch is a type of Mulch that is made from 100% Recycled rubber

Sustainable design

Main article: Sustainable design

Much of the difficulty inherent in recycling comes from the fact that most products are not designed with recycling in mind. Sustainable design (also referred to as "green design" "eco-design" or "design for environment" is the art of designing physical objects the built environment The concept of sustainable design aims to solve this problem, and was first laid out in the book "Cradle to Cradle: Remaking the Way We Make Things" by architect William McDonough and chemist Michael Braungart. Sustainable design (also referred to as "green design" "eco-design" or "design for environment" is the art of designing physical objects the built environment Cradle to Cradle Remaking the Way We Make Things is a 2002 book by German chemist Michael Braungart and U An architect is a licensed individual who leads a design team in the Planning and Design of buildings and participates in oversight of Building Construction A chemist is a Scientist trained in the Science of Chemistry. They suggest that every product (and all packaging they require) should have a complete "closed-loop" cycle mapped out for each component—a way in which every component will either return to the natural ecosystem through biodegradation or be recycled indefinitely. Biodegradation is the process by which organic substances are broken down by the enzymes produced by living organisms ^[6]

As with environmental economics, care much be taken to ensure a complete view of the costs an benefits involved. For example, cardboard packaging for food products is more easily recycled than plastic, but is heavier to ship and may result more waste from spoilage. ^[8]

See also

• Blue bag
• Design for Environment
• Electronic Waste Recycling Fee
• I-recycle
• Recycle It, Don't Trash It!
• Recycling criticism
• Recycling in schools

Types of recycling

• Full Depth Recycling
• Ship-Submarine recycling program
• Thermal depolymerization
• Chemical reclamation, for example hydrochloric acid regeneration

General topics

• Environmentalism
• Waste hierarchy
  • Energy conservation
  • Waste minimisation
  • Pollution Prevention
  • Reuse
    • Regiving
    • Cheapcycle
  • Waste management
    • Extended producer responsibility
    • Pay As You Throw

Trade associations

• International Solid Waste Association
• Solid Waste Association of North America
• Chartered Institute of Wastes Management

References

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