How Recycling Works

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­Recycling is a pretty simple concept: take something that isn't useful anymore and make it into something new instead of just throwing it away. It can be anything from recycling old paper into new paper, to making an old hubcap into a decorative birdbath. In reality, recycling can get pretty complex -- how it interacts with our environment, our politics, our economy and even our own human behavior patterns will play a major role in the future of our planet. In this article, we'll look at what recycling is, why and how it works and some criticisms of the practice. What is Recycling?


Recycling can take many forms. On a small scale, any time you find a new use for something old, you're recycling. One example is making old cereal boxes into magazine holders [source: All Free Crafts].

­Recycling becomes more important on larger scales. At this level, used consumer goods are collected, converted back into raw materials and remade into new consumer products. Aluminum cans, office paper, steel from old buildings and plastic containers are all exam­ples of materials commonly recycled in large quantities, often through municipal programs encouraging bulk household collections.

It's rare for a recycled product to be exactly the same as the original material from which it was recycled. Recycled paper, for example, contains ink residue and has shorter fibers than virgin paper (paper made from wood pulp). Because of this, it may be less desirable for some purposes, such as paper used in a copy machine. When a recycled good i­s cheaper or weaker than the original product, it's known as down-cycling (or downstream recycling). Eventually, goods move so far down the recycling stream it isn't feasible to recycle them any further. After being recycled a few times, paper is no longer usable. In some cases, goods can be up-cycled -- made into something more valuable than the original product. An example of this is a company making upscale, artistic furniture pieces out of old newspapers and aluminum cans [source: Stovell Design].­

Recycling History

Crushed aluminum ready to be recycled into new cans.
Crushed aluminum ready to be recycled into new cans.
Photo courtesy stock.xchng

Although recycling may seem like a modern concept introduced with the environmental movement of the 1970s, it's actually been around for thousands of years. Prior to the industrial age, you couldn't make goods quickly and cheaply, so virtually everyone practiced recycling in some form. However, large-scale recycling programs were very rare -- households predominantly practiced recycling.

The mass production of the industrial age is, in many ways, the very reason we need to worry about large-scale recycling. When products can be produced (and purchased) very cheaply, it often makes more economic sense to simply throw away old items and purchase brand new ones. However, this culture of "disposable" goods created a number of environmental problems, which we'll discuss in detail in the next section.


In the 1930s and 40s, conservation and recycling became important in American society and in many other parts of the world. Economic depressions made recycling a necessity for many people to survive, as they couldn't afford new goods. In the 1940s, goods such as nylon, rubber and many metals were rationed and recycled to help support the war effort. However, the economic boom of the postwar years caused conservationism to fade from the American consciousness [source: Hall]. It wasn't until the environmental movement of the 1960s and 70s, heralded by the first Earth Day in 1970, that recycling once again became a mainstream idea. Though recycling suffered some lean years -- due to public acceptance and the market for recycled goods not growing -- it has generally increased from year to year [source: Hall] The success of recycling traces to wide public acceptance, the improved economics of recycling and laws requiring recycling collections or enforcing recycled content in certain manufacturing processes.

Benefits of Recycling

Garbage overflows at a landfill
Garbage overflows at a landfill
© Photographer: Pryzmat | Agency: Dreamstime

Most of the reasons we recycle are environmental, although some are economic. These include:

Too Much Garbage

One of the main reasons for recycling is to reduce the amount of garbage sent to landfills. Landfill usage peaked in the 1980s, when Americans sent almost 150 million tons (136.08 million metric tons) of garbage to landfills each year. Today, we still dump more than 100 million tons (90.719 million metric tons) of trash into landfills annually [source: Hall]. Even though modern sanitary landfills are safer and less of a nuisance than the open dumps of the past, no one likes having a landfill around. In heavily populated areas, landfill space is scarce. Where space is plentiful, filling it with garbage isn't a very good solution to the problem. Today, recycling efforts in the United States divert 32 percent of waste away from landfills. That prevents more than 60 million tons (54.432 million metric tons) of garbage from ending up in landfills every year [source: EPA].


Pollution from Landfill Leachate

Landfills cause another problem in addition to taking up lots of space. The assortment of chemicals thrown into landfills, plus the chemicals that result when garbage breaks down and blends into a toxic soup known as leachate, creates huge amounts of pollution. Leachate can drain out of the landfill and contaminate groundwater supplies. Today, impermeable clay caps and plastic sheeting prevent much of this run off, making the landfills much safer than they were just a few decades ago. Still, any leachate is too much if it's draining into your neighborhood.

New Goods Use Up Resources

Making a brand-new product without any recycled material causes natural resources to deplete in the manufacturing process. Paper uses wood pulp from trees, while the manufacture of plastics requires the use of fossil fuels like oil and natural gas. Making something from recycled materials means using fewer natural resources.

Recycling (Sometimes) Uses Less Energy

There's room for debate on this aspect of recycling, but many recycling processes require less energy than it would take to manufacture the same item brand-new. Manufacturing plastic is very inexpensive, and some plastic goods can be difficult to recycle efficiently. In those cases, the recycling process probably takes more energy. It can also be difficult to weigh all the energy costs along the entire chain of production. Recycling steel certainly uses less energy than the entire process of mining iron ore, refining it and forging new steel. Some contend that the fleet of recycling trucks collecting plastic and paper door to door every week in cities across the United States tips the balance of energy out of recycling's favor. Energy use is a factor weighed on a case-by-case basis.


Recycling has a variety of economic impacts. For the companies that buy used goods, recycle them and resell new products, recycling is the source of all their income. For cities in densely populated areas that have to pay by the ton for their landfill usage, recycling can shave millions of dollars off municipal budgets. The recycling industry can have an even broader impact. Economic analysis shows that recycling can generate three times as much revenue per ton as landfill disposal and almost six times as many jobs. In the St. Louis area, recycling generates an estimated 16,000 jobs and well more than $4 billion in annual revenue [source: Essential Guide].

Recycling Guidelines

© Photographer: Quayside | Agency: Dreamstime

Almost anything can be recycled, but certain things are more common.


The use of paper in industrialized nations continues to increase, in some cases accounting for almost 20 percent of all household garbage [source: Essential Guide]. Although the trees used to make new paper are a renewable resource, old-growth forests are often chopped down to make room for the pulpwood trees, which are quickly planted and harvested to make paper. Recycled paper results in a significant net savings in terms of water and energy used, as well as pollutants emitted into the environment.


From curbside and workplace collections, paper is sorted based on the type of paper, how heavy it is, what it's used for, its color and whether it was previously recycled. Then a hot chemical and water bath reduces the paper to a soupy, fibrous substance. Magnets, gravity and filters then remove things like staples, glues and other unwanted chemicals from the pulp. The ink is removed by either a chemical wash, or by blowing the ink to the surface where it's skimmed off. The pulp -- which may be bleached -- is then sprayed and rolled into flat sheets, which are pressed and dried. Sometimes new pulp is added to the recycled pulp to make the paper stronger. The giant sheets of paper, when dry, are then cut into the proper size for resale back to consumers [source: Essential Guide].


Recycling glass represents significant energy and cost savings over making virgin glass, because there's virtually no down-cycling when glass is recycled. There are two ways to recycle glass. Some companies collect bottles from their customers and thoroughly wash and disinfect them before reuse. Other glass recyclers sort the glass by color (clear, green and brown glass shouldn't mix because it'll give it a mottled effect). The glass is ground up into fine bits known as cullet, thoroughly sifted and filtered using lasers, magnets and sifters, then melted down and reformed into new glass.

Only glass used in containers like jars and bottles is commonly recycled. Window glass and glass used in light bulbs is too expensive and difficult to recycle.


The recycling of scrap steel from cars and old buildings has a long history in the United States. Steel is relatively easy to recycle -- giant machines shred junk cars and construction waste. In addition, U.S. law requires a certain proportion of all steel to be made with recycled steel -- all U.S. steel contains at least 25 percent recycled steel.

Once sorted, scrap steel is melted down and re-refined into huge sheets or coils. These can be shipped to manufacturers to make car bodies or construction materials.

Other Recycled Items

Bundled papers ready to be recycled.
Bundled papers ready to be recycled.
Photo courtesy stock.xchng


Plastic is a serious problem because it's very cheap to produce, and it's not biodegradable because of its long, complex molecular chains. When plastic is recycled, it's usually made into a new form. The plastic is sorted into different types and colors, filtered and sifted of contaminants, then chopped and melted into pellets or extruded into fibers. These materials can be used many ways: fleece fabric, durable construction materials, molded furniture or insulation.


Aluminum cans are a partial success story -- when they're recycled, they save 95 percent of the energy used to make new cans, not to mention the energy usage and pollution caused by the mining and refining of bauxite, the mineral from which aluminum comes [source: Essential Guide]. The United States recycled 51.9 billion cans in 2006. Thanks to incentives such as five-cent deposits, 51.6 percent of all cans are recycled, more than any other beverage container [source:]. That's why the success is partial -- as impressive as can recycling rates are, we could be doing better. When recycled, cans are chopped up, then heated to remove the paint coating. The pieces melt and mix in a vortex furnace. After being filtered and treated, the molten aluminum is poured into ingots, which are rolled into flat sheets ready to be made into new cans [source: Essential Guide].



Recycling electronic goods isn't as common as recycling cans or plastics. It's labor-intensive to separate the many components of electronic equipment, and market prices for electronic scrap aren't high. In fact, it costs consumers and businesses money to recycle electronics, and there's a variety of toxic materials found in them, such as mercury, lead and chemical refrigerants. However, there are companies that specialize in recycling this "e-waste" and can safely dispose of or reuse these materials for a nominal fee.


There are dozens of other materials that can be recycled. Organic waste can be composted and turned into fertilizer. Rubber tires can be shredded, decontaminated and made into insulation or other innovative products. If you're looking for new ways to recycle, simply give a moment's thought when you throw something out. Could it be reused or broken down in a useful way?

Recycling Centers

Be on the lookout for recycling centers in your area.
Be on the lookout for recycling centers in your area.
Photo courtesy stock.xchng

Recycling programs around the world take four main forms:

Curbside pickup

Special trucks fitted with separate containers for different types of recyclable materials travel city streets just like garbage trucks. Workers do a preliminary sorting of materials as they are thrown into the truck. Some communities require homeowners to sort and separate recyclables themselves, but this can reduce participation rates.


Drop-off centers

A central location is set up to accept recyclable materials, which the homeowners transport themselves. Even communities with curbside pickup may still have drop-off centers for the reclamation of hazardous materials like paint or propane gas.

Buy-back centers

These centers are similar to drop-off centers except they pay homeowners for their items based on market values. These are more commonly seen as part of a retail business, such as an auto scrap yard that buys scrap metal by weight.

Deposit/refund programs

These programs are familiar to anyone in the United States who has ever purchased a beverage in a can or bottle. The deposit -- typically five cents -- is added to the sale price. You can then return the empty bottle or can to a collection center and redeem it for a refund of the deposit.

Many communities struggle to break even with their recycling programs, with cost benefits depending on widespread participation, which is hard to accomplish in large urban areas. If a municipality has committed to a recycling program, it typically becomes illegal to throw away recyclable materials. However, people are rarely prosecuted or fined for this offense.

While the United States recycles more than 30 percent of its solid waste, some European countries have a much higher rate. Germany, Sweden, Austria and the Netherlands enjoy recycling rates from 40 to 60 percent. However, Greece, Ireland and Britain are notorious for low recycling rates. In the developing world, rates are even worse, with recycling all but nonexistent in many nations [source: Essential Guide].

Recycling Criticisms

Look for this logo to see if a product is recycled or for a recycling center.
Look for this logo to see if a product is recycled or for a recycling center.
Photo courtesy stock.xchng

Recycling is gaining increased acceptance worldwide, but not everyone agrees that it's the best way to deal with the environmental problems of garbage. There are several criticisms of recycling.

Recycling Causes Increased Environmental Problems

The process of recycling an old product into something reusable uses energy and creates pollution. Critics claim that recycling is simply a zero-sum game, where the pollutants and waste from making new goods shift into the recycling industry. For some types of recycling, this may be true -- the trade-off between new products and some forms of recycled plastic, for example, are questionable. Nevertheless, there are at least as many ways to recycle that offer clear benefits in terms of energy used, natural resources consumed, pollutants released and landfill space used.


There Isn't Really a Garbage Problem

Some claim that there's no "garbage crisis." They say there's plenty of landfill space -- landfills are a safe and simple way to store as much garbage as we need to put there [source: ECOWorld]. It's true that there's technically plenty of space in the United States and other countries in which to store our garbage, but the thought of filling valleys and fields with garbage doesn't appeal to many people, and certainly not those who live near those valleys and fields.

Recycling Gives Us a False Sense of Security

This criticism closely ties to the problem of recycling causing its own environmental impact. Because of this impact, recycling only represents a minor improvement over landfills or incineration of garbage. Yet, it makes people feel like they've accomplished something important in protecting the environment. Recycling can also enable an attitude of entitled consumerism -- people feel that it's OK to purchase and use environmentally harmful products like bottled water or plastic diapers because they make up for it by recycling. These views point to the ultimate solution: buy less stuff. Purchasing reusable goods or simply buying fewer things we don't need is the best way to stop the garbage stream at the source.

For more information on recycling and related topics, check out the links on the next page.

Lots More Information

Related HowStuffWorks Articles

More Great Links


  • The Aluminum Association, Inc. "U.S. Aluminum Can Recycling Steady in 2006."
  • American Recycler. "Recycled Tires Level the Playing Field."
  • Benjamin, Daniel K. "Recycling Myths: Smothered in Garbage vs. More Landfill Capacity than Ever."
  • Brownfield Golf. "Success Stories: Mountain Gate Country Club, Los Angeles, California."
  • Chang, Kenneth. "Martian Robots, Taking Orders From a Manhattan Walk-Up." The New York Times, Nov. 7, 2004.
  • Cothran, Helen (editor). Opposing Viewpoints Series - Garbage & Recycling. # Greenhaven Press; 1 edition (August 22, 2002). 978-0737712292.
  • Environmental Protection Agency. "Recycling."
  • Hall, Eleanor. Garbage (Our Endangered Planet series). Lucent Books. 1-56006-188-x.
  • Lake, Jane. "Recycling Crafts: Recycled Magazine Holders."
  • McCorquodale, Duncan & Hanaor, Cigalle (editors). Recycle: The Essential Guide. Black Dog Publishing (March 27, 2006). 978-1904772361.
  • Meyers, Brian. "Rewards for recycling considered in Buffalo." The Buffalo News, July 26, 2007.
  • "USS New York."