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Thursday, August 15, 2024

Chemical waste

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Chemical_waste

Chemical waste
is any excess, unused, or unwanted chemical. Chemical waste may be classified as hazardous waste, non-hazardous waste, universal waste, or household hazardous waste, each of which is regulated separately by national governments and the United Nations. Hazardous waste is material that displays one or more of the following four characteristics: ignitability, corrosivity, reactivity, and toxicity. This information, along with chemical disposal requirements, is typically available on a chemical's Safety Data Sheet (SDS). Radioactive and biohazardous wastes require additional or different methods of handling and disposal, and are often regulated differently than standard hazardous wastes.

Laboratory chemical waste in the US

The U.S. Environmental Protection Agency (EPA) prohibits disposing of certain materials down drains. Therefore, when hazardous chemical waste is generated in a laboratory setting, it is usually stored on-site in appropriate waste containers, such as triple-rinsed chemical storage containers or carboys, where it is later collected and disposed of in order to meet safety, health, and legislative requirements. Many universities' Environment, Health, and Safety (EHS) divisions/departments serve this collection and oversight role.

Organic solvents and other organic waste is typically incinerated. Some chemical wastes are recycled, such as waste elemental mercury.

Laboratory waste containment

Laboratory waste containers

Packaging

During packaging, chemical liquid waste containers are filled to no greater than 75% capacity to allow for vapor expansion and to reduce potential spills that can occur from transporting or moving overfilled containers. Containers for chemical liquid waste are typically constructed from materials compatible with the hazardous waste being stored, such as inert materials like polypropylene (PP) or polytetrafluoroethylene (PTFE). These containers are also constructed of mechanically robust materials in order to minimize leakage during storage or transit.

In addition to the general packaging requirements mentioned above, precipitates, solids, and other non-fluid wastes are typically stored separately from liquid waste. Chemically contaminated glassware is disposed of separately from other chemical waste in containers that cannot be punctured by broken glass.

Labelling

Containers may be labelled with the group name from a list of chemical waste categories, along with an itemized list of the contents. All chemicals or materials contaminated by chemicals pose a significant hazard, and as such regulations require that the identity of the chemicals in a waste container is obvious.

Storage

Chemical waste containers are kept closed to prevent spillage, except when waste is being added. Suitable containers are labeled in order to inform disposal specialists of the contents as well as to prevent the addition of incompatible chemicals. Liquid waste is stored in containers with secure screw-top or similar lids that cannot be easily dislodged in transit. Solid waste is stored in various sturdy, chemically inert containers, such as large, sealed buckets or thick plastic bags. Secondary containment, such as trays or safety cabinets, are used to capture spills and leaks from the primary container and to segregate incompatible hazardous wastes, such as acids and bases.

Chemical compatibility guidelines

Many chemicals react adversely when combined. Incompatible chemicals are therefore stored in separate areas of laboratories.

Acids are separated from alkalis, metals, cyanides, sulfides, azides, phosphides, and oxidizers, as when acids combine with these types of compounds, violent exothermic reactions can occur. In addition, some of these reactions produce flammable gases, which, combined with the heat produced, may cause explosions. In the case of cyanides, sulfides, azides, phosphides, etc. Toxic gases are also produced.

Oxidizers are separated from acids, organic materials, metals, reducing agents, and ammonia, as when oxidizers combine with these types of compounds, flammable and sometimes toxic compounds can be created. Oxidizers also increase the likelihood that any flammable material present will ignite, seen most readily in research laboratories with improper storage of organic solvents.

Environmental pollution

Pharmaceuticals

Pharmaceuticals comprise one of the few groups of chemicals that are specifically designed to act on living cells. They present a special risk when they persist in the environment.

With the exception of watercourses downstream of sewage treatment plants, the concentration of pharmaceuticals in surface and ground water is generally low. Concentrations in sewage sludge and in landfill leachate may be substantially higher[21] and provide alternative routes for EPPPs to enter the human and animal food-chain.

However, even at very low environmental concentrations (often ug/L or ng/L), the chronic exposure to environmental pharmaceuticals chemicals can add to the effects of other chemicals in the cocktail is still not studied. The different chemicals might be potentiating synergistic effects (higher than additive effects). An extremely sensitive group in this respect are foetuses.

EPPPs are already found in water all over the world. The diffuse exposure might contribute to

  • extinction of species and imbalance of sensible ecosystems, as many EPPPs affect the reproductive systems of for example frogs, mussels, and fish;
  • genetic, developmental, immune and hormonal health effects to humans and other species, in the same way as e.g. oestrogen-like chemicals;
  • development of microbes resistant to antibiotics, as is found in India.

PPCPs

The use of pharmaceuticals and personal care products (PPCPs) is on the rise with an estimated increase from 2 billion to 3.9 billion annual prescriptions between 1999 and 2009 in the United States alone. PPCPs enter into the environment through individual human activity and as residues from manufacturing, agribusiness, veterinary use, and hospital and community use. In Europe, the input of pharmaceutical residues via domestic waste water is estimated to be around 80% whereas 20% is coming from hospitals. Individuals may add PPCPs to the environment through waste excretion and bathing as well as by directly disposing of unused medications to septic tanks, sewers, or trash. Because PPCPs tend to dissolve relatively easily and do not evaporate at normal temperatures, they often end up in soil and water bodies.

Some PPCPs are broken down or processed easily by a human or animal body and/or degrade quickly in the environment. However, others do not break down or degrade easily. The likelihood or ease with which an individual substance will break down depends on its chemical makeup and the metabolic pathway of the compound.

River pollution

In 2022, the most comprehensive study of pharmaceutical pollution of the world's rivers finds that it threatens "environmental and/or human health in more than a quarter of the studied locations". It investigated 1,052 sampling sites along 258 rivers in 104 countries, representing the river pollution of 470 million people. It found that "the most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing" and lists the most frequently detected and concentrated pharmaceuticals.
Pharmaceutical pollution of the world's rivers by chemical and region

Textile industry

Indigo color water pollution in Phnom Penh, Cambodia, 2005

The textile industry is one of the largest polluters in the globalized world of mostly free market dominated socioeconomic systems. Chemically polluted textile wastewater degrades the quality of the soil and water. The pollution comes from the type of conduct of chemical treatments used e.g., that many or most market-driven companies use despite "eco-friendly alternatives". Textile industry wastewater is considered to be one the largest polluters of water and soil ecosystems, causing "carcinogenic, mutagenic, genotoxic, cytotoxic and allergenic threats to living organisms". The textile industry uses over 8000 chemicals in its supply chain, also polluting the environment with large amounts of microplastics and has been identified in one review as the industry sector producing the largest amount of pollution.

A campaign of big clothing brands like Nike, Adidas and Puma to voluntarily reform their manufacturing supply chains to commit to achieving zero discharges of hazardous chemicals by 2020 (global goal) appears to have failed.

The textile industry also creates a lot of pollution that leads to externalities which can cause large economic problems. The problem usually occurs when there is no division of ownership rights. This means that the problem of pollution is largely caused because of incomplete information about which company pollutes and at what scale the damage was caused by the pollution.

Planetary boundary

A study by "Scienmag" defines a 'planetary boundary' for novel entities such as plastic and chemical pollution. The study reported that the boundary has been crossed.

Regulation of chemical waste

Chemicals waste may fall under regulations such as COSHH in the United Kingdom or the Clean Water Act and Resource Conservation and Recovery Act in the United States. In the U.S., the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA), as well as state and local regulations, also regulate chemical use and disposal.

Chemical waste in Canadian aquaculture

Chemical waste in oceans is becoming a major issue for marine life. There have been many studies conducted to try and prove the effects of chemicals in oceans. In Canada, many of the studies concentrated on the Atlantic provinces, where fishing and aquaculture are an important part of the economy. In New Brunswick, a study was done on sea urchins in an attempt to identify the effects of toxic and chemical waste on life beneath the ocean, specifically the waste from salmon farms. Sea urchins were used to check the levels of metals in the environment. Green sea urchins have been used as they are widely distributed, abundant in many locations, and easily accessible. By investigating the concentrations of metals in the green sea urchins, the impacts of chemicals from salmon aquaculture activity could be assessed and detected. Samples were taken at 25-meter intervals along a transect in the direction of the main tidal flow. The study found that there were impacts to at least 75 meters based on the intestine metal concentrations.

Red mud

From Wikipedia, the free encyclopedia
Red mud near Stade (Germany)
Bauxite, an aluminium ore (Hérault department, France). The reddish colour is due to iron oxides that make up the main part of the red mud.

Red mud, now more frequently termed bauxite residue, is an industrial waste generated during the processing of bauxite into alumina using the Bayer process. It is composed of various oxide compounds, including the iron oxides which give its red colour. Over 97% of the alumina produced globally is through the Bayer process; for every tonne (2,200 lb) of alumina produced, approximately 1 to 1.5 tonnes (2,200 to 3,300 lb) of red mud are also produced; the global average is 1.23. Annual production of alumina in 2023 was over 142 million tonnes (310 billion pounds) resulting in the generation of approximately 170 million tonnes (370 billion pounds) of red mud.

Due to this high level of production and the material's high alkalinity, if not stored properly, it can pose a significant environmental hazard. As a result, significant effort is being invested in finding better methods for safe storage and dealing with it such as waste valorization in order to create useful materials for cement and concrete.

Less commonly, this material is also known as bauxite tailings, red sludge, or alumina refinery residues. Increasingly, the name processed bauxite is being adopted, especially when used in cement applications.

Production

Red mud is a side-product of the Bayer process, the principal means of refining bauxite en route to alumina. The resulting alumina is the raw material for producing aluminium by the Hall–Héroult process. A typical bauxite plant produces one to two times as much red mud as alumina. This ratio is dependent on the type of bauxite used in the refining process and the extraction conditions.

More than 60 manufacturing operations across the world use the Bayer process to make alumina from bauxite ore. Bauxite ore is mined, normally in open cast mines, and transferred to an alumina refinery for processing. The alumina is extracted using sodium hydroxide under conditions of high temperature and pressure. The insoluble part of the bauxite (the residue) is removed, giving rise to a solution of sodium aluminate, which is then seeded with an aluminium hydroxide crystal and allowed to cool which causes the remaining aluminium hydroxide to precipitate from the solution. Some of the aluminium hydroxide is used to seed the next batch, while the remainder is calcined (heated) at over 1,000 °C (1,830 °F) in rotary kilns or fluid flash calciners to produce aluminium oxide (alumina).

The alumina content of the bauxite used is normally between 42 and 50%, but ores with a wide range of alumina contents can be used. The aluminium compound may be present as gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) or diaspore (α-AlO(OH)). The residue invariably has a high concentration of iron oxide which gives the product a characteristic red colour. A small residual amount of the sodium hydroxide used in the process remains with the residue, causing the material to have a high pH/alkalinity, normally above 12. Various stages of solid/liquid separation processes recycle as much sodium hydroxide as possible from the residue back into the Bayer Process, in order to reduce production costs and make the process as efficient as possible. This also lowers the final alkalinity of the residue, making it easier and safer to handle and store.

Composition

Red mud is composed of a mixture of solid and metallic oxides. The red colour arises from iron oxides, which can comprise up to 60% of the mass. The mud is highly basic with a pH ranging from 10 to 13. In addition to iron, the other dominant components include silica, unleached residual aluminium compounds, and titanium oxide.

The main constituents of the residue after the extraction of the aluminium component are insoluble metallic oxides. The percentage of these oxides produced by a particular alumina refinery will depend on the quality and nature of the bauxite ore and the extraction conditions. The table below shows the composition ranges for common chemical constituents, but the values vary widely:

Chemical Percentage composition
Fe2O3 5–60%
Al2O3 5–30%
TiO2 0–15%
CaO 2–14%
SiO2 3–50%
Na2O 1–10%

Mineralogically expressed the components present are:

Chemical name Chemical formula Percentage composition
Sodalite 3Na2O⋅3Al2O3⋅6SiO2⋅Na2SO4 4–40%
Cancrinite Na3⋅CaAl3⋅Si3⋅O12CO3 0–20%
Aluminous-goethite (aluminous iron oxide) α-(Fe,Al)OOH 10–30%
Hematite (iron oxide) Fe2O3 10–30%
Silica (crystalline & amorphous) SiO2 5–20%
Tricalcium aluminate 3CaO⋅Al2O3⋅6H2O 2–20%
Boehmite AlO(OH) 0–20%
Titanium dioxide TiO2 0–10%
Perovskite CaTiO3 0–15%
Muscovite K2O⋅3Al2O3⋅6SiO2⋅2H2O 0–15%
Calcium carbonate CaCO3 2–10%
Gibbsite Al(OH)3 0–5%
Kaolinite Al2O3⋅2SiO2⋅2H2O 0–5%

In general, the composition of the residue reflects that of the non-aluminium components, with the exception of part of the silicon component: crystalline silica (quartz) will not react but some of the silica present, often termed, reactive silica, will react under the extraction conditions and form sodium aluminium silicate as well as other related compounds.

Environmental hazards

Discharge of red mud can be hazardous environmentally because of its alkalinity and species components.

Until 1972, Italian company Montedison was discharging red mud off the coast of Corsica. The case is important in international law governing the Mediterranean sea.

In October 2010, approximately one million cubic metres (35 million cubic feet) of red mud slurry from an alumina plant near Kolontár in Hungary was accidentally released into the surrounding countryside in the Ajka alumina plant accident, killing ten people and contaminating a large area. All life in the Marcal river was said to have been "extinguished" by the red mud, and within days the mud had reached the Danube. The long-term environmental effects of the spill have been minor after a 127 million remediation effort by the Hungarian government.

Residue storage areas

Residue storage methods have changed substantially since the original plants were built. The practice in early years was to pump the slurry, at a concentration of about 20% solids, into lagoons or ponds sometimes created in former bauxite mines or depleted quarries. In other cases, impoundments were constructed with dams or levees, while for some operations valleys were dammed and the residue deposited in these holding areas.

It was once common practice for the red mud to be discharged into rivers, estuaries, or the sea via pipelines or barges; in other instances the residue was shipped out to sea and disposed of in deep ocean trenches many kilometres offshore. From 2016, all disposal into the sea, estuaries and rivers was stopped.

As residue storage space ran out and concern increased over wet storage, since the mid-1980s dry stacking has been increasingly adopted. In this method, residues are thickened to a high density slurry (48–55% solids or higher), and then deposited in a way that it consolidates and dries.

An increasingly popular treatment process is filtration whereby a filter cake (typically resulting in 23–27% moisture) is produced. This cake can be washed with either water or steam to reduce alkalinity before being transported and stored as a semi-dried material. Residue produced in this form is ideal for reuse as it has lower alkalinity, is cheaper to transport, and is easier to handle and process. Another option for ensuring safe storage is to use amphirols to dewater the material once deposited and then 'conditioned' using farming equipment such as harrows to accelerate carbonation and thereby reduce the alkalinity. Bauxite residue produced after press filtration and 'conditioning as described above are classified as non-hazardous under the EU Waste Framework Directive.

In 2013 Vedanta Aluminium, Ltd. commissioned a red mud powder-producing unit at its Lanjigarh refinery in Odisha, India, describing it as the first of its kind in the alumina industry, tackling major environmental hazards.

Use

Since the Bayer process was first adopted industrially in 1894, the value of the remaining oxides has been recognized. Attempts have been made to recover the principal components – especially the iron oxides. Since bauxite mining began, a large amount of research effort has been devoted to seeking uses for the residue. Many studies are now being financed by the European Union under the Horizon Europe programme. Several studies have been conducted to develop uses of red mud. An estimated 3 to 4 million tonnes (6.6 to 8.8 billion pounds) are used annually in the production of cement, road construction and as a source for iron. Potential applications include the production of low cost concrete, application to sandy soils to improve phosphorus cycling, amelioration of soil acidity, landfill capping and carbon sequestration.

Reviews describing the current use of bauxite residue in Portland cement clinker, supplementary cementious materials/blended cements and special calcium aluminate cements (CAC) and calcium sulfo-aluminate (CSA) cements have been extensively researched and documented.[27]

  • Cement manufacture, use in concrete as a supplementary cementitious material. From 500,000 to 1,500,000 tonnes (1.1 to 3.3 billion pounds).[28][29]
  • Raw material recovery of specific components present in the residue: iron, titanium, steel and REE (rare-earth elements) production. From 400,000 to 1,500,000 tonnes;
  • Landfill capping/roads/soil amelioration – 200,000 to 500,000 tonnes;
  • Use as a component in building or construction materials (bricks, tiles, ceramics etc.) – 100,000 to 300,000 tonnes;
  • Other (refractory, adsorbent, acid mine drainage (Virotec), catalyst etc.) – 100,000 tonnes.
  • Use in building panels, bricks, foamed insulating bricks, tiles, gravel/railway ballast, calcium and silicon fertilizer, refuse tip capping/site restoration, lanthanides (rare earths) recovery, scandium recovery, gallium recovery, yttrium recovery, treatment of acid mine drainage, adsorbent of heavy metals, dyes, phosphates, fluoride, water treatment chemical, glass ceramics, ceramics, foamed glass, pigments, oil drilling or gas extraction, filler for PVC, wood substitute, geopolymers, catalysts, plasma spray coating of aluminium and copper, manufacture of aluminium titanate-mullite composites for high temperature resistant coatings, desulfurisation of flue gas, arsenic removal, chromium removal.

In 2015, a major initiative was launched in Europe with funds from the European Union to address the valorization of red mud. Some 15 PhD students were recruited as part the European Training Network (ETN) for Zero-Waste Valorisation of Bauxite Residue. The key focus will be the recovery of iron, aluminium, titanium and rare-earth elements (including scandium) while valorising the residue into building materials. A European Innovation Partnership has been formed to explore options for using by-products from the aluminium industry, BRAVO (Bauxite Residue and Aluminium Valorisation Operations). This sought to bring together industry with researchers and stakeholders to explore the best available technologies to recover critical raw materials but has not proceeded. Additionally, EU funding of approximately €11.5 million has been allocated to a four-year programme starting in May 2018 looking at uses of bauxite residue with other wastes, RemovAL. A particular focus of this project is the installation of pilot plants to evaluate some of the interesting technologies from previous laboratory studies. As part of the H2020 project RemovAl, it is planned to erect a house in the Aspra Spitia area of Greece that will be made entirely out of materials from bauxite residue.

Other EU funded projects that have involved bauxite residue and waste recovery have been ENEXAL (ENergy-EXergy of ALuminium industry) [2010–2014], EURARE (European Rare earth resources) [2013–2017] and three more recent projects are ENSUREAL (ENsuring SUstainable ALumina production) [2017–2021], SIDEREWIN (Sustainable Electro-winning of Iron) [2017–2022] and SCALE (SCandium – ALuminium in Europe) [2016–2020] a €7 million project to look at the recovery of scandium from bauxite residue.

In 2020, the International Aluminium Institute, launched a roadmap for maximising the use of bauxite residue in cement and concrete.

In November 2020, The ReActiv: Industrial Residue Activation for Sustainable Cement Production research project was launched, this is being funded by the EU. One of the world's largest cement companies, Holcim, in cooperation with 20 partners across 12 European countries, launched the ambitious 4-year ReActiv project (reactivproject.eu). The ReActiv project will create a novel sustainable symbiotic value chain, linking the by-product of the alumina production industry and the cement production industry. In ReActiv modification will be made to both the alumina production and the cement production side of the chain, in order to link them through the new ReActiv technologies. The latter will modify the properties of the industrial residue, transforming it into a reactive material (with pozzolanic or hydraulic activity) suitable for new, low CO2 footprint, cement products. In this manner ReActiv proposes a win-win scenario for both industrial sectors (reducing wastes and CO2 emissions respectively).

Fluorchemie GmbH have developed a new flame-retardant additive from bauxite residue, the product is termed MKRS (modified re-carbonised red mud) with the trademark ALFERROCK(R) and has potential applicability in a wide range of polymers (PCT WO2014/000014). One of its particular benefits is the ability to operate over a much broader temperature range, 220–350 °C (428–662 °F), that alternative zero halogen inorganic flame retardants such as aluminium hydroxide, boehmite or magnesium hydroxide. In addition to polymer systems where aluminium hydroxide or magnesium hydroxide can be used, it has also found to be effective in foamed polymers such as EPS and PUR foams at loadings up to 60%.

In a suitable compact solid form, with a density of approximately 3.93 grams per cubic centimetre (0.142 lb/cu in), ALFERROCK produced by the calcination of bauxite residues, has been found to be very effective as a thermal energy storage medium (WO2017/157664). The material can repeatedly be heated and cooled without deterioration and has a specific thermal capacity in the range of 0.6 – 0.8 kJ/(kg·K) at 20 °C (68 °F) and 0.9 – 1.3 kJ/(kg·K) at 726 °C (1,339 °F); this enables the material to work effectively in energy storage device to maximise the benefits of solar power, wind turbines and hydro-electric systems. High strength geopolymers have been developed from red mud.

Sustainable Approach to Low-Grade Bauxite Processing

The IB2 process is a French technology developed to enhance the extraction of alumina from bauxite, especially low-grade bauxite. This method aims to boost alumina production efficiency while decreasing the environmental impacts typically linked with this process, notably the generation of red mud and carbon dioxide emissions.

The IB2 technology, patented in 2019, is the outcome of a decade of research and development efforts by Yves Occello, a former Pechiney chemist. This process improves the traditional Bayer process, which has been utilized for more than a century to extract alumina from bauxite. It presents a significant decrease in caustic soda consumption and a notable reduction in red mud output, thereby minimizing hazardous waste and environmental risks.

In addition to reducing red mud production, the IB2 process aids in lowering CO2 emissions, primarily through the optimized treatment of low-grade bauxite. By limiting the necessity to import high-grade bauxite, this process reduces the carbon footprint associated with ore transportation. Furthermore, the process yields a byproduct that can be utilized in the production of eco-friendly cements, promoting the concept of a circular economy.

The inventor of the technology is chemist Yves Occello, who founded the company IB2 with Romain Girbal in 2017.

Bauxite

From Wikipedia, the free encyclopedia
Reddish-brown bauxite
Bauxite with US penny for comparison
QEMSCAN mineral maps of bauxite ore-forming pisoliths

Bauxite (/ˈbɔːkst/) is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and haematite (Fe2O3), the aluminium clay mineral kaolinite (Al2Si2O5(OH)4) and small amounts of anatase (TiO2) and ilmenite (FeTiO3 or FeO·TiO2). Bauxite appears dull in luster and is reddish-brown, white, or tan.

In 1821, the French geologist Pierre Berthier discovered bauxite near the village of Les Baux in Provence, southern France.

Bauxite extraction and refining has numerous negative consequences to the environment and to people. The negative impacts are well documented and there are many examples from all over the world. These impacts include the destruction of the environment, water, and air soil pollution and soil degradation.

Formation

Bauxite with core of unweathered rock

Numerous classification schemes have been proposed for bauxite but, as of 1982, there was no consensus.

Vadász (1951) distinguished lateritic bauxites (silicate bauxites) from karst bauxite ores (carbonate bauxites):

In the case of Jamaica, recent analysis of the soils showed elevated levels of cadmium, suggesting that the bauxite originates from Miocene volcanic ash deposits from episodes of significant volcanism in Central America.

Production and reserves

World bauxite production in 2005
One of the world's largest bauxite mines in Weipa, in northern Queensland, Australia

Australia is the largest producer of bauxite, followed by Guinea and China. Bauxite is usually strip mined because it is almost always found near the surface of the terrain, with little or no overburden. Increased aluminium recycling, which requires less electric power than producing aluminium from ores, may considerably extend the world's bauxite reserves.

2023 Bauxite production and reserves (thousand tons)
Country Production Reserves
 World 327,000 30,000,000
 Australia 110,000 3,500,000
 Guinea 82,000 7,400,000
 China 60,000 710,000
 Brazil 35,000 2,700,000
 Indonesia 23,000 1,000,000
 India 22,000 650,000
 Jamaica 7,700 2,000,000
 Russia 6,100 480,000
 Kazakhstan 5,800 160,000
 Vietnam 4,000 5,800,000
 Saudi Arabia 4,000 180,000
 Greece 1,800 Undisclosed
 Guyana 1,700 850,000
 Other countries 9,000 4,570,000

Aluminium production

Bauxite being loaded at Cabo Rojo, Dominican Republic, to be shipped elsewhere for processing; 2007

As of 2010, approximately 70% to 80% of the world's dry bauxite production is processed first into alumina and then into aluminium by electrolysis. Bauxite rocks are typically classified according to their intended commercial application: metallurgical, abrasive, cement, chemical, and refractory.

Bauxite ore is usually heated in a pressure vessel along with a sodium hydroxide solution at a temperature of 150 to 200 °C (300 to 390 °F). At these temperatures, the aluminium is dissolved as sodium aluminate (the Bayer process). The aluminium compounds in the bauxite may be present as gibbsite(Al(OH)3), boehmite(AlOOH) or diaspore(AlOOH); the different forms of the aluminium component will dictate the extraction conditions. The undissolved waste, bauxite tailings, after the aluminium compounds are extracted contains iron oxides, silica, calcia, titania and some un-reacted alumina. After separation of the residue by filtering, pure gibbsite is precipitated when the liquid is cooled, and then seeded with fine-grained aluminium hydroxide. The gibbsite is usually converted into aluminium oxide, Al2O3, by heating in rotary kilns or fluid flash calciners to a temperature in excess of 1,000 °C (1,830 °F). This aluminium oxide is dissolved at a temperature of about 960 °C (1,760 °F) in molten cryolite. Next, this molten substance can yield metallic aluminium by passing an electric current through it in the process of electrolysis, which is called the Hall–Héroult process, named after its American and French discoverers.

Prior to the invention of this process, and prior to the Deville process, aluminium ore was refined by heating ore along with elemental sodium or potassium in a vacuum. The method was complicated and consumed materials that were themselves expensive at that time. This made early elemental aluminium more expensive than gold.

Maritime safety

As a bulk cargo, bauxite is a Group A cargo that may liquefy if excessively moist. Liquefaction and the free surface effect can cause the cargo to shift rapidly inside the hold and make the ship unstable, potentially sinking the ship. One vessel suspected to have been sunk in this way was the MS Bulk Jupiter in 2015. One method which can demonstrate this effect is the "can test", in which a sample of the material is placed in a cylindrical can and struck against a surface many times. If a moist slurry forms in the can, then there is a likelihood for the cargo to liquefy; although conversely, even if the sample remains dry it does not conclusively prove that it will remain that way, or that it is safe for loading.

Source of gallium

Bauxite is the main source of the rare metal gallium.

During the processing of bauxite to alumina in the Bayer process, gallium accumulates in the sodium hydroxide liquor. From this it can be extracted by a variety of methods. The most recent is the use of ion-exchange resin. Achievable extraction efficiencies critically depend on the original concentration in the feed bauxite. At a typical feed concentration of 50 ppm, about 15 percent of the contained gallium is extractable. The remainder reports to the red mud and aluminium hydroxide streams.

Bauxite is also a potential source for vanadium.

Socio-ecological impacts

Mineração Rio do Norte (MRN) Bauxite Mine

The social and environmental impacts of bauxite extraction are well documented. Most of the world's bauxite deposits can be found within 1 to 20 metres (3 ft 3 in to 65 ft 7 in) of the earths surface. Strip mining is the most common technique used for extracting shallow bauxite. This process involves removing the vegetation, top soil, and overburden to expose the bauxite ore. The overlying soil is typically stockpiled in order to rehabilitate the mine once operations have finished. During the strip mining process, the biodiversity and habitat once present in the area is completely lost and the hydrological and soil characteristics in the region are permanently altered. Other environmental impacts of bauxite mining include soil degradation, air pollution, and water pollution.

Red mud

Red mud is a highly alkaline sludge, with a high pH around 13, that is a byproduct of the Bayer process. It contains several elements such as sodium aluminoscilicate, calcium titanate, monohydrate aluminium, and trihydrate aluminium that do not break down in nature. When improperly stored, red mud can contaminate soil and water, which can result in local extinction of all life. Red mud was responsible for killing all life in the Marcal River in Hungary after a spill occurred in 2010. When red mud dries, it turns into dust that can cause lung disease, cancer and birth defects.

Conflicts

In the tropical regions of Asia, central Africa, South America and northern Australia, there has been an increase of bauxite mines on traditional and indigenous lands. This has resulted in a number of negative social impacts on local and indigenous peoples. In the Boké Region of Guinea, there has been a significant increase in bauxite mining pressure on the local population. This has resulted in potable water issues, air pollution, food contamination, and land expropriation disputes due to improper compensation.

Bauxite mining has led to protests, civil unrest, and violent conflicts in Guinea, Ghana, Vietnam, and India.

Guinea

Guinea has a long history of mining related conflicts between communities and mining companies. Between 2015 and 2018, new bauxite mining operations in the Boké Region of Guinea have caused in 35 conflicts which include movements of revolts and road blockades. These conflicts have resulted in the loss of human life, the destruction of heavy machinery, and damage to government buildings.

Ghana

The Atewa range in Ghana, classified as an ecologically important forest reserve with an area of 17,400 hectares (43,000 acres), has been is a recent site of conflict and controversy surrounding baxuite mining. The forest reserve is one of the only two upland evergreen forests in Ghana, and makes up a significant portion of the remaining 20% of forested habitat left in Ghana. The Atewa range falls under the jurisdiction of Akyem Abuakwa Traditional Area and is overseen by the king known as Okyenhene. In 2013, an NGO called A Rocha Ghana held a summit with the forestry and water resource commission, the minister of lands, the minister of the environment, and other important stakeholders. They came to the conclusion that no future government should mine bauxite in the region because the reserve is environmentally and culturally significant. In 2016, the government along with NGO's began the process of upgrading the reserved to a national park. However, that year an election took place, and before it became official, the newly elected National Patriotic Party (NPP) rejected the plan. In 2017, the government of Ghana signed a Memorandum of Understanding with China to develop new bauxite mining infrastructure in Ghana. Although there was no official plan to mine the Atewa Forest Reserve, tensions between local communities, NGO and the government began to rise. In 2019, tensions began to reach a peak when the government presented the Ghana Integrated Bauxite and Aluminium Development Authority Act that would create the legal framework required to develop and establish an integrated bauxite industry. In may of that year, the government began drilling deep holes in the reserve. These actions sparked several protests, including a 95-kilometre (59 mi) march from the reserve to the presidential palace, an informational billboard campaign led by A Rocha Ghana, and a youth march. In 2020, A Rocha Ghana also sued the government over the drilling in the reserve after they failed to provide a statement explaining their actions.

Vietnam

In early 2009, the Vietnamese Government proposed a plan to mine remote regions of the central highlands. This proposal was highly controversial and sparked a nationwide debate and the most significant domestic conflict since the Vietnam War. Government scientists, journalists, religious leaders, retired high level state officials, and General Võ Nguyên Giáp, the military leader of anti-colonial revolution, were among the many people across Vietnamese society who opposed the governments plans. In an attempt to stop the spread of information across the globe, the government banned domestic reporters from reporting on bauxite mining. However, reporters turned to Vietnamese language websites and blogs where the reporting and discussion continued. On April 12, 2009, several well-respected Vietnamese scholars started a petition against the mining of bauxite that was signed by 135 accomplished and well known "Intellectuals". This petition helped unite the scattered anti-bauxite movement into a unified opposition against the state. These acts of governmental defiance were met with repressive state actions. Many domestic online reporters were arrested, and legislative action was taken to repress scientific research.

India

Most of India's bauxite ore reserves, which are among the top ten largest in the world, are located on tribal land. These tribal lands are densely populated and home to over 100 million Indigenous Indian peoples.  The mountain summits located on these lands act as a source of water and greatly contribute to the regions fertility. The Indian bauxite industry is interested in developing this land for aluminum production, which poses great risk to the terrestrial and aquatic ecosystems. Historically, the Indigenous peoples living on these lands have shown resistance to development, and oppose any new bauxite mining projects in the area. This has led to violent conflicts between Indigenous communities and police. On December 16, 2000, police killed three Indigenous protestors and wounded over a dozen more during a protest over a bauxite project in the Kashipur region.

Recycling

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Recycling
The three chasing arrows of the universal recycling symbol
Municipal waste recycling rate (%), 2015

Recycling is the process of converting waste materials into new materials and objects. This concept often includes the recovery of energy from waste materials. The recyclability of a material depends on its ability to reacquire the properties it had in its original state. It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. It can also prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, reducing energy use, air pollution (from incineration) and water pollution (from landfilling).

Recycling is a key component of modern waste reduction and is the third component of the "Reduce, Reuse, and Recycle" waste hierarchy. It promotes environmental sustainability by removing raw material input and redirecting waste output in the economic system. There are some ISO standards related to recycling, such as ISO 15270:2008 for plastics waste and ISO 14001:2015 for environmental management control of recycling practice.

Recyclable materials include many kinds of glass, paper, cardboard, metal, plastic, tires, textiles, batteries, and electronics. The composting and other reuse of biodegradable waste—such as food and garden waste—is also a form of recycling. Materials for recycling are either delivered to a household recycling center or picked up from curbside bins, then sorted, cleaned, and reprocessed into new materials for manufacturing new products.

In ideal implementations, recycling a material produces a fresh supply of the same material—for example, used office paper would be converted into new office paper, and used polystyrene foam into new polystyrene. Some types of materials, such as metal cans, can be remanufactured repeatedly without losing their purity. With other materials, this is often difficult or too expensive (compared with producing the same product from raw materials or other sources), so "recycling" of many products and materials involves their reuse in producing different materials (for example, paperboard). Another form of recycling is the salvage of constituent materials from complex products, due to either their intrinsic value (such as lead from car batteries and gold from printed circuit boards), or their hazardous nature (e.g. removal and reuse of mercury from thermometers and thermostats).

History

Origins

Reusing materials has been a common practice for most of human history with recorded advocates as far back as Plato in the fourth century 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 that more waste was recycled in place of new material. However, archaeological artefacts made from recyclable material, such as glass or metal, may neither be the original object nor resemble it, with the consequence that a successful ancient recycling economy can become invisible when recycling is synonymous with re-melting rather than reuse.

Inside a British factory, a textile worker rakes newly-made 'shoddy' which was then combined with new wool to make new cloth

In pre-industrial times, there is evidence of scrap bronze and other metals being collected in Europe and melted down for continuous reuse. Paper recycling was first recorded in 1031 when Japanese shops sold repulped paper. In Britain dust and ash from wood and coal fires was collected by "dustmen" and downcycled as a base material for brick making. These forms of recycling were driven by the economic advantage of obtaining recycled materials instead of virgin material, and the need for waste removal in ever-more-densely populated areas. In 1813, Benjamin Law developed the process of turning rags into "shoddy" and "mungo" wool in Batley, Yorkshire, which combined recycled fibers with virgin wool. The West Yorkshire shoddy industry in towns such as Batley and Dewsbury lasted from the early 19th century to at least 1914.

Industrialization spurred demand for affordable materials. In addition to rags, ferrous scrap metals were coveted as they were cheaper to acquire than virgin ore. Railroads purchased and sold scrap metal in the 19th century, and the growing steel and automobile industries purchased scrap in the early 20th century. Many secondary goods were collected, processed and sold by peddlers who scoured dumps and city streets for discarded machinery, pots, pans, and other sources of metal. By World War I, thousands of such peddlers roamed the streets of American cities, taking advantage of market forces to recycle post-consumer materials into industrial production.

Manufacturers of beverage bottles, including Schweppes, began offering refundable recycling deposits in Great Britain and Ireland around 1800. An official recycling system with refundable deposits for bottles was established in Sweden in 1884, and for aluminum beverage cans in 1982; it led to recycling rates of 84–99%, depending on type (glass bottles can be refilled around 20 times).

Wartime

American poster from World War II
British poster from World War II
Poster from wartime Canada, encouraging housewives to "salvage"
Remnants of iron fence bars in York Whip-Ma-Whop-Ma-Gate. Such public property fences were sawed for the iron and recycled during World War II.

New chemical industries created in the late 19th century both invented new materials (e.g. Bakelite in 1907) and promised to transform valueless into valuable materials. Proverbially, you could not make a silk purse of a sow's ear—until the US firm Arthur D. Little published in 1921 "On the Making of Silk Purses from Sows' Ears", its research proving that when "chemistry puts on overalls and gets down to business [...] new values appear. New and better paths are opened to reach the goals desired."

Recycling—or "salvage", as it was then usually known—was a major issue for governments during World War II, where financial constraints and significant material shortages made it necessary to reuse goods and recycle materials. These resource shortages caused by the world wars, and other such world-changing events, greatly encouraged recycling. It became necessary for most homes to recycle their waste, allowing people to make the most of what was available. Recycling household materials also meant more resources were left available for war efforts. Massive government campaigns, such as the National Salvage Campaign in Britain and the Salvage for Victory campaign in the United States, occurred in every fighting nation, urging citizens to donate metal, paper, rags, and rubber as a patriotic duty.

Post-World War II

A considerable investment in recycling occurred in the 1970s due to rising energy costs. Recycling aluminium uses only 5% of the energy of virgin production. Glass, paper and other metals have less dramatic but significant energy savings when recycled.

Although consumer electronics have been popular since the 1920s, recycling them was almost unheard of until early 1991. The first electronic waste recycling scheme was implemented in Switzerland, beginning with collection of old refrigerators, then expanding to cover all devices. When these programs were created, many countries could not deal with the sheer quantity of e-waste, or its hazardous nature, and began to export the problem to developing countries without enforced environmental legislation. (For example, recycling computer monitors in the United States costs 10 times more than in China.) Demand for electronic waste in Asia began to grow when scrapyards found they could extract valuable substances such as copper, silver, iron, silicon, nickel, and gold during the recycling process. The 2000s saw a boom in both the sales of electronic devices and their growth as a waste stream: In 2002, e-waste grew faster than any other type of waste in the EU. This spurred investment in modern automated facilities to cope with the influx, especially after strict laws were implemented in 2003.

As of 2014, the European Union had about 50% of world share of waste and recycling industries, with over 60,000 companies employing 500,000 people and a turnover of €24 billion. EU countries are mandated to reach recycling rates of at least 50%; leading countries are already at around 65%. The overall EU average was 39% in 2013 and is rising steadily, to 45% in 2015.

In 2015, the United Nations General Assembly set 17 Sustainable Development Goals. Goal 12, Responsible Consumption and Production, specifies 11 targets "to ensure sustainable consumption and production patterns". The fifth target, Target 12.5, is defined as substantially reducing waste generation by 2030, indicated by the National Recycling Rate.

In 2018, changes in the recycling industry have sparked a global "crisis". On 31 December 2017, China announced its "National Sword" policy, setting new standards for imports of recyclable material and banning materials deemed too "dirty" or "hazardous". The new policy caused drastic disruptions in the global recycling market, and reduced the prices of scrap plastic and low-grade paper. Exports of recyclable materials from G7 countries to China dropped dramatically, with many shifting to countries in southeast Asia. This generated significant concern about the recycling industry's practices and environmental sustainability. The abrupt shift caused countries to accept more materials than they could process, and raised fundamental questions about shipping waste from developed countries to countries with few environmental regulations—a practice that predated the crisis.

Health and environmental impact

Health impact

E-waste

According to the WHO (2023), “Every year millions of electrical and electronic devices are discarded ... a threat to the environment and to human health if they are not treated, disposed of, and recycled appropriately. Common items ... include computers ... e-waste are recycled using environmentally unsound techniques and are likely stored in homes and warehouses, dumped, exported or recycled under inferior conditions. When e-waste is treated using inferior activities, it can release as many as 1000 different chemical substances ... including harmful neurotoxicants such as lead.”

Slag recycling

Copper slag is obtained when copper and nickel ores are recovered from their source ores using a pyrometallurgical process, and these ores usually contain other elements which include iron, cobalt, silica, and alumina.An estimate of 2.2–3 tons of copper slag is generated per ton of copper produced, resulting in around 24.6 tons of slag per year, which is regarded as waste.

Environmental impact of slag include copper paralysis, which leads to death due to gastric hemorrhage, if ingested by humans. It may also cause acute dermatitis upon skin exposure.  Toxicity may also be uptaken by crops through soil, consequently spreading animals and food sources and increasing the risk of cardiovascular diseases, cancer, cognitive impairment, chronic anemia, and damage to kidneys, bones, nervous system, brain and skin.

Substituting gravel and grit in quarries has been more cost-effective, due to having its sources with better proximity to consumer markets. Trading between countries and establishment of blast furnaces is helping increase slag utilization, hence reducing wastage and pollution.

Environmental impact

Economist Steven Landsburg, author of a paper entitled "Why I Am Not an Environmentalist", claimed that paper recycling actually reduces tree populations. He argues that because paper companies have incentives to replenish their forests, large demands for paper lead to large forests while reduced demand for paper leads to fewer "farmed" forests.

A metal scrap worker is pictured burning insulated copper wires for copper recovery at Agbogbloshie, Ghana.

When foresting companies cut down trees, more are planted in their place; however, such farmed forests are inferior to natural forests in several ways. Farmed forests are not able to fix the soil as quickly as natural forests. This can cause widespread soil erosion and often requiring large amounts of fertilizer to maintain the soil, while containing little tree and wild-life biodiversity compared to virgin forests. Also, the new trees planted are not as big as the trees that were cut down, and the argument that there would be "more trees" is not compelling to forestry advocates when they are counting saplings.

In particular, wood from tropical rainforests is rarely harvested for paper because of their heterogeneity. According to the United Nations Framework Convention on Climate Change secretariat, the overwhelming direct cause of deforestation is subsistence farming (48% of deforestation) and commercial agriculture (32%), which is linked to food, not paper production.

Other non-conventional methods of material recycling, like Waste-to-Energy (WTE) systems, have garnered increased attention in the recent past due to the polarizing nature of their emissions. While viewed as a sustainable method of capturing energy from material waste feedstocks by many, others have cited numerous explanations for why the technology has not been scaled globally.

Legislation

Supply

For a recycling program to work, a large, stable supply of recyclable material is crucial. Three legislative options have been used to create such supplies: mandatory recycling collection, container deposit legislation, and refuse bans. Mandatory collection laws set recycling targets for cities, 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 responsible for working to meet this target.

Container deposit legislation mandates refunds 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 that the consumer can reclaim when the container is returned to a collection point. These programs have succeeded in creating an average 80% recycling rate. Despite such good results, the shift in collection costs from local government to industry and consumers has created strong opposition in some areas—for example, where manufacturers bear the responsibility for recycling their products. In the European Union, the WEEE Directive requires producers of consumer electronics to reimburse the recyclers' costs.

An alternative way to increase the supply of recyclates is to ban the disposal of certain materials as waste, often including used oil, old batteries, tires, and garden waste. This can create a viable economy for the proper disposal of the products. Care must be taken that enough recycling services exist to meet the supply, or such bans can create increased illegal dumping.

Government-mandated demand

Four forms of legislation have also been used to increase and maintain the demand for recycled materials: minimum recycled content mandates, utilization rates, procurement policies, and recycled product labeling.

Both minimum recycled content mandates and utilization rates increase demand 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. Utilization rates are a more flexible option: Industries can meet their recycling targets at any point of their operations, or even contract out recycling in exchange for tradable credits. Opponents to these methods cite their large increase in reporting requirements, and claim that they rob the industry of flexibility.

Governments have used their own purchasing power to increase recycling demand through "procurement policies". These policies are either "set-asides", which reserve a certain amount of spending for recycled products; or "price preference" programs that provide larger budgets when recycled items are purchased. Additional regulations can target specific cases: in the United States, 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 final government regulation toward increased demand is recycled product labeling. When producers are required to label their packaging with the amount of recycled material it contains (including the packaging), consumers can make more educated choices. Consumers with sufficient buying power can choose more environmentally conscious options, prompting producers to increase the recycled material in their products and increase demand. Standardized recycling labeling can also have a positive effect on the supply of recyclates when it specifies how and where the product can be recycled.

Recyclates

Glass recovered by crushing only one kind of beer bottle

"Recyclate" is a raw material sent to and processed in a waste recycling plant or materials-recovery facility so it can be used in the production of new materials and products. For example, plastic bottles can be made into plastic pellets and synthetic fabrics.

Quality of recyclate

The quality of recyclates is one of the principal challenges for the success of a long-term vision of a green economy and achieving zero waste. It generally refers to how much of it is composed of target material, versus non-target material and other non-recyclable material. Steel and other metals have intrinsically higher recyclate quality; it is estimated that two-thirds of all new steel comes from recycled steel. Only target material is likely to be recycled, so higher amounts of non-target and non-recyclable materials can reduce the quantity of recycled products. A high proportion of non-target and non-recyclable material can make it more difficult to achieve "high-quality" recycling; and if recyclate is of poor quality, it is more likely to end up being down-cycled or, in more extreme cases, sent to other recovery options or landfilled. For example, to facilitate the remanufacturing of clear glass products, there are tight restrictions for colored glass entering the re-melt process. Another example is the downcycling of plastic, where products such as plastic food packaging are often downcycled into lower quality products, and do not get recycled into the same plastic food packaging.

The quality of recyclate not only supports high-quality recycling, but it can also deliver significant environmental benefits by reducing, reusing, and keeping products out of landfills. High-quality recycling can support economic growth by maximizing the value of waste material. Higher income levels from the sale of quality recyclates can return value significant to local governments, households and businesses. Pursuing high-quality recycling can also promote consumer and business confidence in the waste and resource management sector, and may encourage investment in it.

There are many actions along the recycling supply chain, each of which can affect recyclate quality. Waste producers who place non-target and non-recyclable wastes in recycling collections can affect the quality of final recyclate streams, and require extra efforts to discard those materials at later stages in the recycling process. Different collection systems can induce different levels of contamination. When multiple materials are collected together, extra effort is required to sort them into separate streams and can significantly reduce the quality of the final products. Transportation and the compaction of materials can also make this more difficult. Despite improvements in technology and quality of recyclate, sorting facilities are still not 100% effective in separating materials. When materials are stored outside, where they can become wet, can also cause problems for re-processors. Further sorting steps may be required to satisfactorily reduce the amount of non-target and non-recyclable material.

Recyclate Quality Action Plan (Scotland)

Scotland's Recyclate Quality Action Plan proposes a number of actions the Scottish Government wants to take to increase the quality of materials collected for recycling and sorted at recovery facilities before it is exported or sold on the reprocessing market. Its objectives are to:

  • Increase recyclate quality, and create greater transparency about it.
  • Help those contracting with recycling facilities identify what is required of them.
  • Ensure compliance with the Waste (Scotland) Regulations 2012.
  • Stimulate a household market for quality recyclate.
  • Address and reduce issues around waste shipment regulations.

The plan focuses on three key areas, with 14 actions to increase the quality of materials collected, sorted and presented to the processing market in Scotland. These areas are:

  • Collection systems and input contamination
  • Sorting facilities—material sampling and transparency
  • Material quality benchmarking and standards

Recycling consumer waste

Collection

A three-sided bin at a railway station in Germany, intended to separate paper (left) and plastic wrappings (right) from other waste (back)

A number of systems have been implemented to collect recyclates from the general waste stream, occupying different places on the spectrum of trade-off between public convenience and government ease and expense. The three main categories of collection are drop-off centers, buy-back centers and curbside collection. About two-thirds of the cost of recycling is incurred in the collection phase.

Curbside collection

A recycling truck collecting the contents of a recycling bin in Canberra, Australia
Emptying of segregated rubbish containers in Tomaszów Mazowiecki, Poland

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. A waste collection vehicle generally picks up the waste.

In mixed waste collection, recyclates are collected mixed with the rest of the waste, and the desired materials are sorted out and cleaned at a central sorting facility. This results in a large amount of recyclable waste (especially paper) being too soiled to reprocess, but has advantages as well: The city need not pay for the separate collection of recyclates, no public education is needed, and any changes to the recyclability of certain materials are implemented where sorting occurs.

In a commingled or single-stream system, recyclables are mixed but kept separate from non-recyclable waste. This greatly reduces the need for post-collection cleaning, but requires public education on what materials are recyclable.

Source separation

Source separation is the other extreme, where each material is cleaned and sorted prior to collection. It requires the least post-collection sorting and produces the purest recyclates. However, it incurs additional operating costs for collecting each material, and requires extensive public education to avoid recyclate contamination. In Oregon, USA, Oregon DEQ surveyed multi-family property managers; about half of them reported problems, including contamination of recyclables due to trespassers such as transients gaining access to collection areas.

Source separation used to be the preferred method due to the high cost of sorting commingled (mixed waste) collection. However, advances in sorting technology have substantially lowered this overhead, and many areas that had developed source separation programs have switched to what is called co-mingled collection.

Buy-back centers

Reverse vending machine in Tomaszów Mazowiecki, Poland

At buy-back centers, separated, cleaned recyclates are purchased, providing a clear incentive for use and creating a stable supply. The post-processed material can then be sold. If profitable, this conserves the emission of greenhouse gases; if unprofitable, it increases their emission. Buy-back centres generally need government subsidies to be viable. According to a 1993 report by the U.S. National Waste & Recycling Association, it costs an average $50 to process a ton of material that can be resold for $30.

Drop-off centers

A drop-off center in the United Kingdom, where they are generally named Recycling Centres

Drop-off centers require the waste producer to carry recyclates to a central location—either an 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.

Distributed recycling

For some waste materials such as plastic, recent technical devices called recyclebots enable a form of distributed recycling called DRAM (distributed recycling additive manufacturing). Preliminary life-cycle analysis (LCA) indicates that such distributed recycling of HDPE to make filament for 3D printers in rural regions consumes less energy than using virgin resin, or using conventional recycling processes with their associated transportation.

Another form of distributed recycling mixes waste plastic with sand to make bricks in Africa. Several studies have looked at the properties of recycled waste plastic and sand bricks. The composite pavers can be sold at 100% profit while employing workers at 1.5× the minimum wage in the West African region, where distributed recycling has the potential to produce 19 million pavement tiles from 28,000 tons of plastic water sachets annually in Ghana, Nigeria, and Liberia. This has also been done with COVID19 masks.

Sorting

Once commingled recyclates are collected and delivered to a materials recovery facility, the materials must be sorted. This is done in a series of stages, many of which involve automated processes, enabling a truckload of material to be fully sorted in less than an hour. Some plants can now sort materials automatically; this is known as single-stream recycling. Automatic sorting may be aided by robotics and machine learning. In plants, a variety of materials is sorted including paper, different types of plastics, glass, metals, food scraps, and most types of batteries. A 30% increase in recycling rates has been seen in areas with these plants. In the US, there are over 300 materials recovery facilities.

Initially, commingled recyclates are removed from the collection vehicle and placed on a conveyor belt spread out in a single layer. Large pieces of corrugated fiberboard and plastic bags are removed by hand at this stage, as they can cause later machinery to jam.

Early sorting of recyclable materials: glass and plastic bottles in Poland.

Next, automated machinery such as disk screens and air classifiers separate the recyclates by weight, splitting lighter paper and plastic from heavier glass and metal. Cardboard is removed from mixed paper, and the most common types of plastic—PET (#1) and HDPE (#2)—are collected, so these materials can be diverted into the proper collection channels. This is usually done by hand; but in some sorting centers, spectroscopic scanners are used to differentiate between types of paper and plastic based on their absorbed wavelengths. Plastics tend to be incompatible with each other due to differences in chemical composition; their polymer molecules repel each other, similar to oil and water.

Strong magnets are used to separate out ferrous metals such as iron, steel and tin cans. Non-ferrous metals are ejected by magnetic eddy currents: A rotating magnetic field induces an electric current around aluminum cans, creating an eddy current inside the cans that is repulsed by a large magnetic field, ejecting the cans from the stream.

A recycling point in New Byth, Scotland, with separate containers for paper, plastics, and differently colored glass

Finally, glass is sorted according to its color: brown, amber, green, or clear. It may be sorted either by hand, or by a machine that uses colored filters to detect colors. Glass fragments smaller than 10 millimetres (0.39 in) cannot be sorted automatically, and are mixed together as "glass fines".

In 2003, San Francisco's Department of the Environment set a citywide goal of zero waste by 2020. San Francisco's refuse hauler, Recology, operates an effective recyclables sorting facility that has helped the city reach a record-breaking landfill diversion rate of 80% as of 2021. Other American cities, including Los Angeles, have achieved similar rates.

Recycling industrial waste

Mounds of shredded rubber tires ready for processing

Although many government programs concentrate on recycling at home, 64% of waste in the United Kingdom is generated by industry. The focus of many recycling programs in industry is their cost-effectiveness. The ubiquitous nature of cardboard packaging makes cardboard a common waste product recycled by companies that deal heavily in packaged goods, such as retail stores, warehouses, and goods distributors. Other industries deal in niche and specialized products, depending on the waste materials they handle.

Glass, lumber, wood pulp and paper manufacturers all deal directly in commonly recycled materials; however, independent tire dealers may collect and recycle rubber tires for a profit.

The waste produced from burning coal in a Coal-fired power station is often called fuel ash or fly ash in the United States. It is a very useful material and used in concrete construction. It exhibits Pozzolanic activity.

Levels of metals recycling are generally low. In 2010, the International Resource Panel, hosted by the United Nations Environment Programme (UNEP), published reports on metal stocks and their recycling rates. It reported that the increase in the use of metals during the 20th and into the 21st century has led to a substantial shift in metal stocks from below-ground to use in above-ground applications within society. For example, in the US, in-use copper grew from 73 to 238 kg per capita between 1932–1999.

The report's authors observed that, as metals are inherently recyclable, metal stocks in society can serve as huge above-ground mines (the term "urban mining" has thus been coined). However, they found that the recycling rates of many metals are low. They warned that the recycling rates of some rare metals used in applications such as mobile phones, battery packs for hybrid cars and fuel cells, are so low that unless future end-of-life recycling rates are dramatically increased, these critical metals will become unavailable for use in modern technology.

The military recycles some metals. The U.S. Navy's Ship Disposal Program uses ship breaking to reclaim the steel of old vessels. Ships may also be sunk to create artificial reefs. Uranium is a dense metal that has qualities superior to lead and titanium for many military and industrial uses. Uranium left over from processing it into nuclear weapons and fuel for nuclear reactors is called depleted uranium, and is used by all branches of the U.S. military for the development of such things as armor-piercing shells and shielding.

The construction industry may recycle concrete and old road surface pavement, selling these materials for profit.

Some rapidly growing industries, particularly the renewable energy and solar photovoltaic technology industries, are proactively creating recycling policies even before their waste streams have considerable volume, anticipating future demand.

Recycling of plastics is more difficult, as most programs are not able to reach the necessary level of quality. Recycling of PVC often results in downcycling of the material, which means only products of lower quality standard can be made with the recycled material.

Computer processors retrieved from waste stream

E-waste is a growing problem, accounting for 20–50 million metric tons of global waste per year according to the EPA. It is also the fastest growing waste stream in the EU. Many recyclers do not recycle e-waste responsibly. After the cargo barge Khian Sea dumped 14,000 metric tons of toxic ash in Haiti, the Basel Convention was formed to stem the flow of hazardous substances into poorer countries. They created the e-Stewards certification to ensure that recyclers are held to the highest standards for environmental responsibility and to help consumers identify responsible recyclers. It operates alongside other prominent legislation, such as the Waste Electrical and Electronic Equipment Directive of the EU and the United States National Computer Recycling Act, to prevent poisonous chemicals from entering waterways and the atmosphere.

In the recycling process, television sets, monitors, cell phones, and computers are typically tested for reuse and repaired. If broken, they may be disassembled for parts still having high value if labor is cheap enough. Other e-waste is shredded to pieces roughly 10 centimetres (3.9 in) in size and manually checked to separate toxic batteries and capacitors, which contain poisonous metals. The remaining pieces are further shredded to 10 millimetres (0.39 in) particles and passed under a magnet to remove ferrous metals. An eddy current ejects non-ferrous metals, which are sorted by density either by a centrifuge or vibrating plates. Precious metals can be dissolved in acid, sorted, and smelted into ingots. The remaining glass and plastic fractions are separated by density and sold to re-processors. Television sets and monitors must be manually disassembled to remove lead from CRTs and the mercury backlight from LCDs.

Vehicles, solar panels and wind turbines can also be recycled. They often contain rare-earth elements (REE) and/or other critical raw materials. For electric car production, large amounts of REE's are typically required.

Whereas many critical raw elements and REE's can be recovered, environmental engineer Phillipe Bihouix Archived 6 September 2021 at the Wayback Machine reports that recycling of indium, gallium, germanium, selenium, and tantalum is still very difficult and their recycling rates are very low.

Plastic recycling

A container for recycling used plastic spoons into material for 3D printing

Plastic recycling is the process of recovering scrap or waste plastic and reprocessing the material into useful products, sometimes completely different in form from their original state. For instance, this could mean melting down soft drink bottles and then casting them as plastic chairs and tables. For some types of plastic, the same piece of plastic can only be recycled about 2–3 times before its quality decreases to the point where it can no longer be used.

Physical recycling

Some plastics are remelted to form new plastic objects; for example, PET water bottles can be converted into polyester destined for clothing. A disadvantage of this type of recycling is that the molecular weight of the polymer can change further and the levels of unwanted substances in the plastic can increase with each remelt.

A commercial-built recycling facility was sent to the International Space Station in late 2019. The facility takes in plastic waste and unneeded plastic parts and physically converts them into spools of feedstock for the space station additive manufacturing facility used for in-space 3D printing.

Chemical recycling

For some polymers, it is possible to convert them back into monomers, for example, PET can be treated with an alcohol and a catalyst to form a dialkyl terephthalate. The terephthalate diester can be used with ethylene glycol to form a new polyester polymer, thus making it possible to use the pure polymer again. In 2019, Eastman Chemical Company announced initiatives of methanolysis and syngas designed to handle a greater variety of used material.

Waste plastic pyrolysis to fuel oil

Another process involves the conversion of assorted polymers into petroleum by a much less precise thermal depolymerization process. Such a process would be able to accept almost any polymer or mix of polymers, including thermoset materials such as vulcanized rubber tires and the biopolymers in feathers and other agricultural waste. Like natural petroleum, the chemicals produced can be used as fuels or as feedstock. A RESEM Technology plant of this type in Carthage, Missouri, US, uses turkey waste as input material. Gasification is a similar process but is not technically recycling since polymers are not likely to become the result. Plastic Pyrolysis can convert petroleum based waste streams such as plastics into quality fuels, carbons. Given below is the list of suitable plastic raw materials for pyrolysis:

Recycling loops

Loops for production-waste, product and material recycling

The (ideal) recycling process can be differentiated into three loops, one for manufacture (production-waste recycling) and two for disposal of the product (product and material recycling).

The product's manufacturing phase, which consists of material processing and fabrication, forms the production-waste recycling loop. Industrial waste materials are fed back into, and reused in, the same production process.

The product's disposal process requires two recycling loops: product recycling and material recycling. The product or product parts are reused in the product recycling phase. This happens in one of two ways: the product is used retaining the product functionality ("reuse") or the product continues to be used but with altered functionality ("further use"). The product design is unmodified, or only slightly modified, in both scenarios.

Product disassembly requires material recycling where product materials are recovered and recycled. Ideally, the materials are processed so they can flow back into the production process.

Recycling codes

Recycling codes on products

In order to meet recyclers' needs while providing manufacturers a consistent, uniform system, a coding system was developed. The recycling code for plastics was introduced in 1988 by the plastics industry through the Society of the Plastics Industry. Because municipal recycling programs traditionally have targeted packaging—primarily bottles and containers—the resin coding system offered a means of identifying the resin content of bottles and containers commonly found in the residential waste stream.

In the United States, plastic products are printed with numbers 1–7 depending on the type of resin. Type 1 (polyethylene terephthalate) is commonly found in soft drink and water bottles. Type 2 (high-density polyethylene) is found in most hard plastics such as milk jugs, laundry detergent bottles, and some dishware. Type 3 (polyvinyl chloride) includes items such as shampoo bottles, shower curtains, hula hoops, credit cards, wire jacketing, medical equipment, siding, and piping. Type 4 (low-density polyethylene) is found in shopping bags, squeezable bottles, tote bags, clothing, furniture, and carpet. Type 5 is polypropylene and makes up syrup bottles, straws, Tupperware, and some automotive parts. Type 6 is polystyrene and makes up meat trays, egg cartons, clamshell containers, and compact disc cases. Type 7 includes all other plastics such as bulletproof materials, 3- and 5-gallon water bottles, cell phone and tablet frames, safety goggles and sunglasses. Having a recycling code or the chasing arrows logo on a material is not an automatic indicator that a material is recyclable but rather an explanation of what the material is. Types 1 and 2 are the most commonly recycled.

Cost–benefit analysis

Environmental effects of recycling
Material Energy savings vs. new production Air pollution savings vs. new production
Aluminium 95% 95%
Cardboard 24%  —
Glass 5–30% 20%
Paper 40% 73%
Plastics 70%  —
Steel 60%  —

In addition to environmental impact, there is debate over whether recycling is economically efficient. According to a Natural Resources Defense Council study, waste collection and landfill disposal creates less than one job per 1,000 tons of waste material managed; in contrast, the collection, processing, and manufacturing of recycled materials creates 6–13 or more jobs per 1,000 tons. According to the U.S. Recycling Economic Informational Study, there are over 50,000 recycling establishments that have created over a million jobs in the US. The National Waste & Recycling Association (NWRA) reported in May 2015 that recycling and waste made a $6.7 billion economic impact in Ohio, U.S., and employed 14,000 people. Economists would classify this extra labor used as a cost rather than a benefit since these workers could have been employed elsewhere; the cost effectiveness of creating these additional jobs remains unclear.

Sometimes cities have found recycling saves resources compared to other methods of disposal of waste. Two years after New York City declared that implementing recycling programs would be "a drain on the city", New York City leaders realized that an efficient recycling system could save the city over $20 million. Municipalities often see fiscal benefits from implementing recycling programs, largely due to the reduced landfill costs. A study conducted by the Technical University of Denmark according to the Economist found that in 83 percent of cases, recycling is the most efficient method to dispose of household waste. However, a 2004 assessment by the Danish Environmental Assessment Institute concluded that incineration was the most effective method for disposing of drink containers, even aluminium ones.

Fiscal efficiency is separate from economic efficiency. Economic analysis of recycling does not include what economists call externalities: unpriced costs and benefits that accrue to individuals outside of private transactions. Examples include less air pollution and greenhouse gases from incineration and less waste leaching from landfills. Without mechanisms such as taxes or subsidies, businesses and consumers following their private benefit would ignore externalities despite the costs imposed on society. If landfills and incinerator pollution is inadequately regulated, these methods of waste disposal appear cheaper than they really are, because part of their cost is the pollution imposed on people nearby. Thus, advocates have pushed for legislation to increase demand for recycled materials. The United States Environmental Protection Agency (EPA) has concluded in favor of recycling, saying that recycling efforts reduced the country's carbon emissions by a net 49 million metric tonnes in 2005. In the United Kingdom, the Waste and Resources Action Programme stated that Great Britain's recycling efforts reduce CO2 emissions by 10–15 million tonnes a year. The question for economic efficiency is whether this reduction is worth the extra cost of recycling and thus makes the artificial demand creates by legislation worthwhile.

Wrecked automobiles gathered for smelting

Certain requirements must be met 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. 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".

Free-market economist Julian Simon remarked "There are three ways society can organize waste disposal: (a) commanding, (b) guiding by tax and subsidy, and (c) leaving it to the individual and the market". These principles appear to divide economic thinkers today.

Frank Ackerman favours a high level of government intervention to provide recycling services. He believes that recycling's benefit cannot be effectively quantified by traditional laissez-faire economics. Allen Hershkowitz supports intervention, saying that it is a public service equal to education and policing. He argues that manufacturers should shoulder more of the burden of waste disposal.

Paul Calcott and Margaret Walls advocate the second option. A deposit refund scheme and a small refuse charge would encourage recycling but not at the expense of illegal dumping. Thomas C. Kinnaman concludes that a landfill tax would force consumers, companies and councils to recycle more.

Most free-market thinkers detest subsidy and intervention, arguing that they waste resources. The general argument is that if cities charge the full cost of garbage collection, private companies can profitably recycle any materials for which the benefit of recycling exceeds the cost (e.g. aluminum) and do not recycle other materials for which the benefit is less than the cost (e.g. glass). Cities, on the other hand, often recycle even when they not only do not receive enough for the paper or plastic to pay for its collection, but must actually pay private recycling companies to take it off of their hands. Terry Anderson and Donald Leal think that all recycling programmes should be privately operated, and therefore would only operate if the money saved by recycling exceeds its costs. Daniel K. Benjamin argues that it wastes people's resources and lowers the wealth of a population. He notes that recycling can cost a city more than twice as much as landfills, that in the United States landfills are so heavily regulated that their pollution effects are negligible, and that the recycling process also generates pollution and uses energy, which may or may not be less than from virgin production.

Trade in recyclates

Certain countries trade in unprocessed recyclates. Some have complained that the ultimate fate of recyclates sold to another country is unknown and they may end up in landfills instead of being reprocessed. According to one report, in America, 50–80 percent of computers destined for recycling are actually not recycled. 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. Although the Chinese government has banned these practices, it has not been able to eradicate them. In 2008, the prices of recyclable waste plummeted before rebounding in 2009. Cardboard averaged about £53/tonne from 2004 to 2008, dropped to £19/tonne, and then went up to £59/tonne in May 2009. PET plastic averaged about £156/tonne, dropped to £75/tonne and then moved up to £195/tonne in May 2009.

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 U.S. 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.

Similarly, the northwestern United States has difficulty finding markets for recycled newspaper, given the large number of pulp mills in the region as well as the proximity to Asian markets. In other areas of the U.S., however, demand for used newsprint has seen wide fluctuation.

In some U.S. states, a program called RecycleBank pays people to recycle, receiving money from local municipalities for the reduction in landfill space that must be purchased. It uses a single stream process in which all material is automatically sorted.

Criticisms and responses

Critics dispute the net economic and environmental benefits of recycling over its costs, and suggest that proponents of recycling often make matters worse and suffer from confirmation bias. Specifically, critics argue that the costs and energy used in collection and transportation detract from (and outweigh) the costs and energy saved in the production process; also that the jobs produced by the recycling industry can be a poor trade for the jobs lost in logging, mining, and other industries associated with production; and that materials such as paper pulp can only be recycled a few times before material degradation prevents further recycling.

Journalist John Tierney notes that it is generally more expensive for municipalities to recycle waste from households than to send it to a landfill and that "recycling may be the most wasteful activity in modern America."

Much of the difficulty inherent in recycling comes from the fact that most products are not designed with recycling in mind. The concept of sustainable design aims to solve this problem, and was laid out in the 2002 book Cradle to Cradle: Remaking the Way We Make Things by architect William McDonough and chemist Michael Braungart. They suggest that every product (and all packaging it requires) should have a complete "closed-loop" cycle mapped out for each component—a way in which every component either returns to the natural ecosystem through biodegradation or is recycled indefinitely.

Complete recycling is impossible from a practical standpoint. In summary, substitution and recycling strategies only delay the depletion of non-renewable stocks and therefore may buy time in the transition to true or strong sustainability, which ultimately is only guaranteed in an economy based on renewable resources.

— M. H. Huesemann, 2003

While recycling diverts waste from entering directly into landfill sites, current recycling misses the dispersive components. Critics believe that complete recycling is impracticable as highly dispersed wastes become so diluted that the energy needed for their recovery becomes increasingly excessive.

As with environmental economics, care must be taken to ensure a complete view of the costs and benefits involved. For example, paperboard packaging for food products is more easily recycled than most plastic, but is heavier to ship and may result in more waste from spoilage.

Energy and material flows

Bales of crushed steel ready for transport to the smelter

The amount of energy saved through recycling depends upon the material being recycled and the type of energy accounting that is used. Correct accounting for this saved energy can be accomplished with life-cycle analysis using real energy values, and in addition, exergy, which is a measure of how much useful energy can be used. In general, it takes far less energy to produce a unit mass of recycled materials than it does to make the same mass of virgin materials.

Some scholars use emergy (spelled with an m) analysis, for example, budgets for the amount of energy of one kind (exergy) that is required to make or transform things into another kind of product or service. Emergy calculations take into account economics that can alter pure physics-based results. Using emergy life-cycle analysis researchers have concluded that materials with large refining costs have the greatest potential for high recycle benefits. Moreover, the highest emergy efficiency accrues from systems geared toward material recycling, where materials are engineered to recycle back into their original form and purpose, followed by adaptive reuse systems where the materials are recycled into a different kind of product, and then by-product reuse systems where parts of the products are used to make an entirely different product.

The Energy Information Administration (EIA) states on its website that "a paper mill uses 40 percent less energy to make paper from recycled paper than it does to make paper from fresh lumber." Some critics argue that it takes more energy to produce recycled products than it does to dispose of them in traditional landfill methods, since the curbside collection of recyclables often requires a second waste truck. However, recycling proponents point out that a second timber or logging truck is eliminated when paper is collected for recycling, so the net energy consumption is the same. An emergy life-cycle analysis on recycling revealed that fly ash, aluminum, recycled concrete aggregate, recycled plastic, and steel yield higher efficiency ratios, whereas the recycling of lumber generates the lowest recycle benefit ratio. Hence, the specific nature of the recycling process, the methods used to analyse the process, and the products involved affect the energy savings budgets.

It is difficult to determine the amount of energy consumed or produced in waste disposal processes in broader ecological terms, where causal relations dissipate into complex networks of material and energy flow.

[C]ities do not follow all the strategies of ecosystem development. Biogeochemical paths become fairly straight relative to wild ecosystems, with reduced recycling, resulting in large flows of waste and low total energy efficiencies. By contrast, in wild ecosystems, one population's wastes are another population's resources, and succession results in efficient exploitation of available resources. However, even modernized cities may still be in the earliest stages of a succession that may take centuries or millennia to complete.

How much energy is used in recycling also depends on the type of material being recycled and the process used to do so. Aluminium is generally agreed to use far less energy when recycled rather than being produced from scratch. The EPA states that "recycling aluminum cans, for example, saves 95 percent of the energy required to make the same amount of aluminum from its virgin source, bauxite." In 2009, more than half of all aluminium cans produced came from recycled aluminium. Similarly, it has been estimated that new steel produced with recycled cans reduces greenhouse gas emissions by 75%.

Every year, millions of tons of materials are being exploited from the earth's crust, and processed into consumer and capital goods. After decades to centuries, most of these materials are "lost". With the exception of some pieces of art or religious relics, they are no longer engaged in the consumption process. Where are they? Recycling is only an intermediate solution for such materials, although it does prolong the residence time in the anthroposphere. For thermodynamic reasons, however, recycling cannot prevent the final need for an ultimate sink.

— P. H. Brunner

Economist Steven Landsburg has suggested that the sole benefit of reducing landfill space is trumped by the energy needed and resulting pollution from the recycling process. Others, however, have calculated through life-cycle assessment that producing recycled paper uses less energy and water than harvesting, pulping, processing, and transporting virgin trees. When less recycled paper is used, additional energy is needed to create and maintain farmed forests until these forests are as self-sustainable as virgin forests.

Other studies have shown that recycling in itself is inefficient to perform the "decoupling" of economic development from the depletion of non-renewable raw materials that is necessary for sustainable development. The international transportation or recycle material flows through "... different trade networks of the three countries result in different flows, decay rates, and potential recycling returns". As global consumption of a natural resources grows, their depletion is inevitable. The best recycling can do is to delay; complete closure of material loops to achieve 100 percent recycling of nonrenewables is impossible as micro-trace materials dissipate into the environment causing severe damage to the planet's ecosystems. Historically, this was identified as the metabolic rift by Karl Marx, who identified the unequal exchange rate between energy and nutrients flowing from rural areas to feed urban cities that create effluent wastes degrading the planet's ecological capital, such as loss in soil nutrient production. Energy conservation also leads to what is known as Jevon's paradox, where improvements in energy efficiency lowers the cost of production and leads to a rebound effect where rates of consumption and economic growth increases.

This shop in New York only sells items recycled from demolished buildings.

Costs

The amount of money actually saved through recycling depends on the efficiency of the recycling program used to do it. The Institute for Local Self-Reliance argues that the cost of recycling depends on various factors, such as landfill fees and the amount of disposal that the community recycles. It states that communities begin to save money when they treat recycling as a replacement for their traditional waste system rather than an add-on to it and by "redesigning their collection schedules and/or trucks".

In some cases, the cost of recyclable materials also exceeds the cost of raw materials. Virgin plastic resin costs 40 percent less than recycled resin. Additionally, a United States Environmental Protection Agency (EPA) study that tracked the price of clear glass from 15 July to 2 August 1991, found that the average cost per ton ranged from $40 to $60 while a USGS report shows that the cost per ton of raw silica sand from years 1993 to 1997 fell between $17.33 and $18.10.

Comparing the market cost of recyclable material with the cost of new raw materials ignores economic externalities—the costs that are currently not counted by the market. Creating a new piece of plastic, for instance, may cause more pollution and be less sustainable than recycling a similar piece of plastic, but these factors are not counted in market cost. A life cycle assessment can be used to determine the levels of externalities and decide whether the recycling may be worthwhile despite unfavorable market costs. Alternatively, legal means (such as a carbon tax) can be used to bring externalities into the market, so that the market cost of the material becomes close to the true cost.

Working conditions

Some people in Brazil earn their living by collecting and sorting garbage and selling them for recycling.

The recycling of waste electrical and electronic equipment can create a significant amount of pollution. This problem is specifically occurrent in India and China. Informal recycling in an underground economy of these countries has generated an environmental and health disaster. High levels of lead (Pb), polybrominated diphenylethers (PBDEs), polychlorinated dioxins and furans, as well as polybrominated dioxins and furans (PCDD/Fs and PBDD/Fs), concentrated in the air, bottom ash, dust, soil, water, and sediments in areas surrounding recycling sites. These materials can make work sites harmful to the workers themselves and the surrounding environment.

Possible income loss and social costs

In some countries, recycling is performed by the entrepreneurial poor such as the karung guni, zabbaleen, the rag-and-bone man, waste picker, and junk man. With the creation of large recycling organizations that may be profitable, either by law or economies of scale, the poor are more likely to be driven out of the recycling and the remanufacturing job market. To compensate for this loss of income, a society may need to create additional forms of societal programs to help support the poor. Like the parable of the broken window, there is a net loss to the poor and possibly the whole of a society to make recycling artificially profitable, e.g. through the law. However, in Brazil and Argentina, waste pickers/informal recyclers work alongside the authorities, in fully or semi-funded cooperatives, allowing informal recycling to be legitimized as a paid public sector job.

Because the social support of a country is likely to be less than the loss of income to the poor undertaking recycling, there is a greater chance for the poor to come in conflict with the large recycling organizations. This means fewer people can decide if certain waste is more economically reusable in its current form rather than being reprocessed. Contrasted to the recycling poor, the efficiency of their recycling may actually be higher for some materials because individuals have greater control over what is considered "waste".

One labor-intensive underused waste is electronic and computer waste. Because this waste may still be functional and wanted mostly by those on lower incomes, who may sell or use it at a greater efficiency than large recyclers.

Some recycling advocates believe that laissez-faire individual-based recycling does not cover all of society's recycling needs. Thus, it does not negate the need for an organized recycling program. Local government can consider the activities of the recycling poor as contributing to the ruining of property.

Public participation rates

Single-stream recycling increases public participation rates, but requires additional sorting.
Better recycling is a priority in the European Union, especially in Central and Eastern Europe among respondents of the 2020-21 European Investment Bank Climate Survey.

Changes that have been demonstrated to increase recycling rates include:

In a study done by social psychologist Shawn Burn, it was found that personal contact with individuals within a neighborhood is the most effective way to increase recycling within a community. In her study, she had 10 block leaders talk to their neighbors and persuade them to recycle. A comparison group was sent fliers promoting recycling. It was found that the neighbors that were personally contacted by their block leaders recycled much more than the group without personal contact. As a result of this study, Shawn Burn believes that personal contact within a small group of people is an important factor in encouraging recycling. Another study done by Stuart Oskamp examines the effect of neighbors and friends on recycling. It was found in his studies that people who had friends and neighbors that recycled were much more likely to also recycle than those who did not have friends and neighbors that recycled.

Many schools have created recycling awareness clubs in order to give young students an insight on recycling. These schools believe that the clubs actually encourage students to not only recycle at school but at home as well.

Recycling of metals varies extremely by type. Titanium and lead have an extremely high recycling rates of over 90%. Copper and cobalt have high rates of recycling around 75%. Only about half of aluminum is recycled. Most of the remaining metals have recycling rates of below 35%, while 34 types of metals have recycling rates of under 1%.

"Between 1960 and 2000, the world production of plastic resins increased 25 times its original amount, while recovery of the material remained below 5 percent." Many studies have addressed recycling behaviour and strategies to encourage community involvement in recycling programs. It has been argued that recycling behavior is not natural because it requires a focus and appreciation for long-term planning, whereas humans have evolved to be sensitive to short-term survival goals; and that to overcome this innate predisposition, the best solution would be to use social pressure to compel participation in recycling programs. However, recent studies have concluded that social pressure does not work in this context. One reason for this is that social pressure functions well in small group sizes of 50 to 150 individuals (common to nomadic hunter–gatherer peoples) but not in communities numbering in the millions, as we see today. Another reason is that individual recycling does not take place in the public view.

Following the increasing popularity of recycling collection being sent to the same landfills as trash, some people kept on putting recyclables on the recyclables bin.

Recycling in art

A survey showing the share of firms taking action by recycling and waste minimisation
Uniseafish – made of recycled aluminum beer cans

Art objects are more and more often made from recycled material.

Embracing a circular economy through advanced sorting technologies

By extending the lifespan of goods, parts, and materials, a circular economy seeks to minimize waste and maximize resource utilization. Advanced sorting techniques like optical and robotic sorting may separate and recover valuable materials from waste streams, lowering the requirement for virgin resources and accelerating the shift to a circular economy.

Community engagement, such as education and awareness campaigns, may support the acceptance of recycling and reuse programs and encourage the usage of sustainable practices. One can lessen our influence on the environment, save natural resources, and generate economic possibilities by adopting a circular economy using cutting-edge sorting technology and community engagement. According to Melati et al., to successfully transition to a circular economy, legislative and regulatory frameworks must encourage sustainable practices while addressing possible obstacles and difficulties in putting these ideas into action.

Lie group

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Lie_group In mathematics , a Lie gro...