Recycling

Recycling is the process of turning waste materials into new things we can use. It helps us save important resources and keeps our planet healthier. When we recycle, we take things like paper, glass, metal, and plastic that we no longer need and turn them into new products instead of throwing them away.

This helps reduce pollution and saves energy because making products from recycled materials usually uses less energy than creating them from scratch. Recycling also cuts down on the amount of waste that ends up in landfills or is burned, which can hurt the air and water.

Many everyday items can be recycled, such as bottles, cans, newspapers, and old clothes. People often put these items in special bins at home or take them to recycling centers. From there, the materials are sorted, cleaned, and turned into new products. By recycling, we help protect our environment and make sure we have resources for the future.

History

Long ago, when people didn’t have many things, they often reused waste materials instead of throwing them away. Ancient waste dumps show that people recycled more when resources were hard to find. They melted down metals and reused glass, even if the new items looked different from the old ones.

In earlier times, people collected scrap metals and reused paper. In Japan, shops sold recycled paper as early as 1031. In Britain, ash and dust from fires were used to make bricks. During World War II, governments asked everyone to recycle metals, paper, and rubber to help with the war effort. After the war, recycling became important again because it saved energy. Today, many countries work hard to recycle more materials to protect the environment.

Health and environmental impact

Health impact

E-waste

Main article: Electronic waste

Every year, millions of electrical and electronic devices are thrown away. If not treated, disposed of, and recycled properly, they can harm the environment and human health. Common items include computers. When e-waste is recycled using unsafe methods, it can release many harmful chemicals, including substances that can affect the brain and nervous system, such as lead.

Slag recycling

Copper slag is a by-product made when copper and nickel are taken from ores. It contains other elements like iron and silica. A lot of copper slag is made each year and is often considered waste. If not handled safely, copper slag can be harmful to humans and the environment. It can cause skin problems and affect health if taken in through food or water. Using slag instead of gravel in construction can save money and reduce pollution.

Environmental impact

Some people argue that paper recycling might actually reduce the number of trees because paper companies plant new trees when they cut down old ones. However, these new forests are not as healthy as natural forests. They don’t protect the soil as well and need lots of fertilizer to grow. These forests also have less wildlife than natural forests. Most deforestation is caused by farming for food, not by paper production.

Other ways to recycle materials, like turning waste into energy, are debated because of concerns about emissions. Some see it as a good way to get energy from waste, while others worry it hasn’t been used widely enough.

Legislation

For a recycling program to work well, there needs to be a steady supply of materials that can be recycled. There are three main ways laws can help create this supply: mandatory recycling collection, container deposit laws, and bans on throwing away certain items. Mandatory collection laws require cities to recycle a certain amount of materials by a specific date. Container deposit laws add a small extra cost to drinks in glass, plastic, or metal containers. People can get this extra money back when they return the empty containers, which has helped increase recycling rates to around 80% in some places. Another way to increase recycling is by banning the disposal of things like old oil, batteries, tires, and garden waste, which can create new ways to safely dispose of these items.

Governments can also create demand for recycled materials through four main methods: requiring products to contain a certain amount of recycled materials, allowing industries to meet recycling goals in flexible ways, using government buying power to prefer recycled products, and requiring labels on products to show how much recycled material they contain. These labels help consumers make better choices and encourage producers to use more recycled materials.

Types of recycling

Recycling can be sorted into different kinds depending on how it is done and what it makes. One kind is mechanical recycling, where materials like plastics and metals are broken apart, melted, and shaped again. Another is chemical recycling, where materials are split into their basic parts to be used in making new things.

There is also closed-loop recycling, where materials are turned back into the same product without losing much quality, and open-loop recycling, where materials are made into different products, sometimes with less quality. Closed-loop recycling is thought to be better because it helps save resources.

Recyclates

"Recyclate" is a material that is taken to a recycling plant to be cleaned and prepared so it can be used to make new things. For example, plastic bottles can be turned into small pieces and used to make synthetic fabrics.

The quality of recyclates is very important for making good use of materials and helping the environment. Good quality means the material is mostly what we want to recycle, without many other things mixed in. Metals like steel are easy to recycle and often used again. But if there are many unwanted materials, it can be harder to recycle properly. Sometimes lower quality materials are used to make different products instead of the same kind of thing.

Good quality recycling helps protect the environment and can also save money. It makes sure valuable materials are not wasted and can be reused. Keeping materials clean and separate helps make the best possible use of them.

Recycling consumer waste

See also: Post-consumer waste

Collection

There are different ways to collect materials that can be recycled from everyday waste. These methods balance how easy it is for people to recycle and how much it costs the government. The main ways to collect recyclables are drop-off centers, buy-back centers, and curbside collection. About two-thirds of the cost of recycling happens during the collection phase.

Curbside collection

Main article: Curbside collection

Curbside collection has many different systems, mostly differing in how recyclables are sorted and cleaned. The main types are mixed waste collection, commingled recyclables, and source separation. A waste collection vehicle usually picks up the waste.

In mixed waste collection, recyclables are collected together with other waste. The desired materials are sorted and cleaned at a central facility. This can lead to a lot of recyclable waste, especially paper, being too dirty to reuse. However, it has benefits: the city doesn’t need to pay for separate collection, no public education is needed, and changes to what can be recycled can be made at the sorting facility.

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

Source separation

Source separation is where each material is cleaned and sorted before collection. It needs the least sorting after collection and produces the purest recyclables. However, it costs more to collect each material and needs lots of public education to avoid contamination. In Oregon, USA, Oregon DEQ found that many property managers had problems, including contamination from people who aren’t supposed to use the collection areas.

Source separation used to be the preferred method because sorting mixed waste was very expensive. But better sorting technology has made this easier, so many places that used source separation have switched to co-mingled collection.

Buy-back centers

At buy-back centers, cleaned recyclables are bought, which encourages people to use them and creates a steady supply. The processed material can then be sold. If this is profitable, it helps reduce greenhouse gases; if not, it can increase them. Buy-back centers often need government money to stay open. A 1993 report by the U.S. National Waste & Recycling Association said it costs about $50 to process a ton of material that can be sold for $30.

Drop-off centers

Drop-off centers need people to take recyclables to a central place, like a collection station or reprocessing plant. They are the easiest to set up but don’t get used much or in a predictable way.

Distributed recycling

For some materials like plastic, new devices called recyclebots allow a form of distributed recycling called DRAM (distributed recycling additive manufacturing). Early studies show that recycling HDPE to make filament for 3D printers in rural areas uses less energy than using new plastic or traditional recycling with transportation.

Another way mixes waste plastic with sand to make bricks in Africa. Studies have looked at the properties of these bricks. They can be sold for profit while paying workers more in West Africa, where this method could make millions of tiles from thousands of tons of plastic bags each year in Ghana, Nigeria, and Liberia. This has also been done with COVID19 masks.

Sorting

Once recyclables are collected and taken to a materials recovery facility, they need to be sorted. This happens in steps, many using machines, so a truckload can be sorted in less than an hour. Some plants can sort materials automatically using robotics and machine learning. In plants, materials like paper, plastics, glass, metals, food scraps, and batteries are sorted. A 30% increase in recycling rates has been seen in areas with these plants. In the US, there are over 300 materials recovery facilities.

First, recyclables are taken from the truck and placed on a conveyor belt in a single layer. Large pieces of corrugated fiberboard and plastic bags are removed by hand because they can jam machines.

Next, machines such as disk screens and air classifiers separate materials by weight, splitting lighter paper and plastic from heavier glass and metal. Cardboard is separated from mixed paper, and the most common plastics—PET (#1) and HDPE (#2)—are collected so they can go to the right place. This is usually done by hand, but some centers use spectroscopic scanners to tell different types of paper and plastic apart based on how they absorb light. Plastics don’t mix well because their chemical composition is different; their polymer molecules push each other away, like oil and water.

Strong magnets are used to separate metals like iron, steel, and tin cans. Non-ferrous metals are moved by magnetic eddy currents: A rotating magnetic field induces an electric current in aluminum cans, creating a current that pushes the cans away from the stream.

Finally, glass is sorted by color: brown, amber, green, or clear. It can be sorted by hand or by a machine that uses colored filters to find colors. Small glass pieces, less than 10 millimetres (0.39 in), can’t be sorted automatically and are mixed together as “glass fines”.

In 2003, San Francisco’s Department of the Environment set a goal to have zero waste by 2020. San Francisco’s waste hauler, Recology, runs an effective sorting facility that helped the city reach an 80% landfill diversion rate by 2021. Other American cities, including Los Angeles, have achieved similar rates.

Recycling industrial waste

Many recycling programs focus on homes, but industry creates a lot of waste too. In fact, about 64% of waste in the United Kingdom comes from industry. Companies often recycle to save money. Cardboard is a common waste material because it is used a lot in packaging for stores, warehouses, and other businesses.

Industries that work with glass, wood pulp, paper, and rubber tires also recycle these materials. Burning coal in power stations creates waste called fuel ash or fly ash, which is used in concrete building. Recycling metals is important, but many metals, especially rare ones used in phones and cars, are recycled at low rates. This means we may run out of these metals if we don't improve recycling.

Some industries, like renewable energy and solar technology, are making plans to recycle their waste before it becomes a big problem. Recycling plastics can be tricky because it is hard to make them into high-quality products again.

Further information: Computer recycling

Further information: Battery recycling

Further information: Solar panel § Recycling

Further information: Wind turbine § Demolition and recycling

E-waste, such as old televisions, computers, and phones, is a big problem. It makes up a lot of global waste. Some recyclers do not handle e-waste properly, which can harm the environment. Rules like the Basel Convention help make sure e-waste is handled safely.

In recycling e-waste, broken items are fixed or taken apart for useful parts. The rest is broken into small pieces and sorted to remove dangerous materials. Metals are separated and cleaned, and the remaining pieces are sold to be made into new products.

Vehicles, solar panels, and wind turbines can also be recycled because they contain important materials. However, recycling some metals like indium and gallium is still very hard.

Plastic recycling

Main article: Plastic recycling

Plastic recycling means taking old plastic and making new products from it. For example, soft drink bottles can be melted and made into chairs or tables. Most plastics can only be recycled a few times before they lose quality.

Some plastics are melted to make new items, like turning water bottles into clothing material. In space, a special recycling machine on the International Space Station turns plastic waste into materials for 3D printing.

Other ways to recycle plastic include breaking it down into its original building blocks or turning it into fuel through heating. This can handle many types of plastic, including mixed plastics and rubber tires.

Recycling codes

To help make recycling easier, a special system of codes was created. These codes were introduced in 1988 to help people know what kind of plastic something is made from. In the United States, plastic items often have numbers from 1 to 7 printed on them.

Type 1, made from polyethylene terephthalate, is used in soft drink and water bottles. Type 2, made from high-density polyethylene, is found in milk jugs, laundry detergent bottles, and some dishware. These two types are the most commonly recycled. Other types include polyvinyl chloride for shampoo bottles and credit cards, low-density polyethylene for shopping bags, polypropylene for syrup bottles and Tupperware, and polystyrene for meat trays and egg cartons. Type 7 covers all other plastics that don’t fit into the first six categories. The code or symbol on an item tells what it’s made from but doesn’t always mean it can be recycled.

Cost–benefit analysis

Sometimes cities find that recycling saves money compared to other ways of getting rid of waste. For example, New York City first thought recycling would cost too much, but later found it could save over $20 million. Many cities benefit from recycling because it helps reduce the cost of using landfills. A study found that in most cases, recycling is the best way to handle household waste. However, for some items like drink containers, burning them might be better.

Recycling can also help the environment by reducing pollution and greenhouse gases. But for recycling to work well, there needs to be a steady supply of materials to recycle, a way to collect them, factories to process them, and demand for the recycled products. Without all these pieces, recycling isn't complete.

Different people have different ideas about how to manage recycling. Some think the government should help, while others believe the market should handle it on its own. Some suggest using taxes or charges to encourage recycling, while others argue that private companies should only recycle materials that save money to process.

Criticisms and responses

Much of the difficulty in recycling comes from the fact that most products are not designed with recycling in mind. In the USA, only around 6 to 7 percent of plastic gets recycled. The idea of sustainable design aims to solve this problem. This idea was explained in a 2002 book by architect William McDonough and chemist Michael Braungart. They suggest that every product and all its packaging should have a clear plan for what happens after it is used—either it should break down naturally or be recycled forever.

While recycling helps keep waste out of landfills, it can’t catch everything. Some critics say that it’s impossible to recycle everything because some wastes spread out too much, making it take too much energy to collect them.

When thinking about recycling, it’s important to look at all the costs and benefits. For example, paperboard for food is easier to recycle than most plastic, but it’s heavier to ship and might lead to more food being wasted. Sometimes, the money spent on recycling can lead to dishonest behavior.

Net environmental benefits

Critics argue that recycling might not always save money or help the environment as much as people think. They say that the energy and costs of collecting and moving recyclables can outweigh the savings in making new products. They also say that recycling jobs might not make up for jobs lost in other industries like logging or mining. For example, paper can only be recycled a few times before it breaks down.

The amount of energy saved by recycling depends on what material is being recycled. It usually takes less energy to make something from recycled materials than from new ones. For example, making paper from recycled paper uses 40 percent less energy than making it from new trees. Recycling aluminum cans saves 95 percent of the energy needed to make new aluminum. Similarly, using recycled steel can cut greenhouse gas emissions by 75 percent.

However, some say that recycling can’t fully stop us from running out of natural resources. Even with recycling, materials will eventually spread out too much and cause harm to the environment.

Economic costs

Some people say that it’s more expensive for towns to recycle household waste than to send it to a landfill. The money saved through recycling depends on how well the program is run. In some places, recycled materials cost more than new materials. For example, new plastic resin costs 40 percent less than recycled resin. However, these costs don’t always account for hidden problems like pollution from making new materials.

Working conditions and social costs

Recycling waste electronics can create pollution, especially in some countries. This can harm both workers and the environment. In some places, poor people have traditionally made a living by collecting and recycling waste. But as bigger recycling companies grow, these individuals may lose their jobs. Some countries have tried to help by creating programs to support these workers, allowing them to work with local authorities. However, there can be conflicts between small recyclers and large companies over what should be recycled and how.

Public participation rates

There are ways to help more people recycle. One way is called single-stream recycling, where all types of recyclables go into one bin. Another way is pay as you throw fees, where you pay more for throwing away trash instead of recycling it.

Studies show that talking to people in person can really help. When block leaders spoke to their neighbors about recycling, those neighbors recycled more than people who just got flyers. Having friends and neighbors who recycle also makes people more likely to recycle.

Many schools start recycling clubs to teach students about recycling. These clubs help students recycle both at school and at home.

Recycling rates for metals differ a lot. Some metals, like titanium and lead, are recycled over 90% of the time. Others, like copper and cobalt, are recycled around 75%. Only about half of aluminum gets recycled. Most other metals have recycling rates below 35%, and some have rates under 1%.

Between 1960 and 2000, the amount of plastic made grew a lot, but less than 5% of it was recycled. Some people still put recyclables in the trash bin instead of the recycling bin.

Recycling in art

Art objects are now often created using recycled materials. This means artists are using old or waste materials to make new and interesting pieces.

Embracing a circular economy through advanced sorting technologies

A circular economy helps us use resources better by keeping items and materials in use longer. This means less waste and more chances to reuse what we already have. New sorting tools, like special machines and robots, can pick out useful materials from our trash, so we don’t need to use as many new resources.

Getting everyone involved is important too. Teaching people about recycling and reusing can help everyone support these ideas. By working together and using new technology, we can help protect nature, save resources, and create new jobs.