by Chris Woodford. Last updated: February 12, 2019.
During your lifetime, you'll produce over 600 times your own weight in trash—enough to fill a good few trucks.  That staggering statistic might not be such a problem if we didn't have to live on a relatively small, overcrowded planet. Pretty much all the resources we have on Earth—all the raw materials and an awful lot of the energy—are limited: once we've used them up, we won't get any more. So it makes sense to use things as wisely as we can.
The best way to use Earth's resources more sensibly is to reduce the amount of things that we use (for example, less packaging on food in shops) and to reuse things instead of throwing them away (reusing carrier bags at the grocery store makes a lot of sense). If we can't reduce or reuse, and we have to throw things away, recycling them is far better than simply tossing them out in the trash. Let's take a closer look at recycling and how it works!
Photo: Separating waste is the key to recycling. This seaside recycling bin in Dorset, England has separate compartments for bottles (green), cans (silver), and paper (blue).
Why is recycling important?
Photo: Jefferson County landfill. Photo by David Parsons courtesy of US Department of Energy/National Renewable Energy Laboratory (NREL).
When you throw stuff away, you might be very glad to get rid of it:
the trash it goes, never to be seen again! Unfortunately, that's not
the end of the story. The things we throw away have to go
somewhere—usually they go off to be
a landfill or burnt in an incinerator. Landfills can be horribly
polluting. They look awful, they stink, they take up space that could
be used for better things, and they sometimes create toxic soil and
that can kill fish in our rivers and seas.
One of the worst things about landfills is that they're wasting a huge amount of potentially useful material. It takes a lot of energy and a lot of resources to make things and when we throw those things in a landfill, at the end of their lives, we're also saying goodbye to all the energy and resources they contain. Some authorities like to burn their trash in giant incinerators instead of burying it in landfills. That certainly has advantages: it reduces the amount of waste that has to be buried and it can generate useful energy. But it can also produce toxic air pollution and burning almost anything (except plants that have grown very recently) adds to the problem of global warming and climate change.
The trouble is, we're all in the habit of throwing stuff away. In the early part of the 20th century, people used materials much more wisely—especially in World War II (1939–1945), when many raw materials were in short supply.  But in recent decades we've become a very disposable society. We tend to buy new things instead of getting old ones repaired. A lot of men use disposable razors, for example, instead of buying reusable ones, while a lot of women wear disposable nylon stockings. Partly this is to do with the sheer convenience of throwaway items. It's also because they're cheap: artificial plastics, made from petroleum-based materials, became extremely inexpensive and widely available after the end of World War II. But that wasteful period in our history is coming to an end.
We're finally starting to realize that our live-now, pay-later lifestyle is storing up problems for future generations. Earth is soon going to be running on empty if we carry on as we are. Americans live in much greater affluence than virtually anyone else on Earth. What happens when people in developing countries such as India and China decide they want to live the same way as us? According to the environmentalists Paul Hawken, Amory Lovins, and Hunter Lovins, we'd need two Earths to satisfy all their needs. If everyone on Earth doubles their standard of living in the next 40 years, we'll need 12 Earths to satisfy them! 
Why should you recycle?
If everyone reduced, reused, and recycled, we could make Earth's resources go an awful lot further. Recycling saves materials, reduces the need to landfill and incinerate, cuts down pollution, and helps to make the environment more attractive. It also creates jobs, because recycling things takes a bit more effort than making new things. Recycling doesn't just save materials: it saves energy too. Manufacturing things uses a lot of energy from power plants—and hungry power plants generally make global warming worse. We can save a surprising amount of energy by recycling. If you recycle a single aluminum can you save about 95 percent of the energy it would take to make a brand new one.  That's enough energy saved to power your television for about 3 hours!  You'll often hear people say that over half the trash we throw away can be recycled. Looking at the chart below, you can see that we currently recycle somewhere between 30–90 percent of the various different materials we use. Just imagine if everyone were recycling most of their garbage: together, we'd be making a tremendous reduction in the amount of raw materials and energy we use—and doing a lot of good for the planet.
Chart: Percentage recycling rates in the United States for various materials. Drawn in 2019 by explainthatstuff.com using the latest available data, taken from the following sources: Steel: US Geological Survey; Aluminum: US Geological Survey; Aluminum cans: Aluminum Association; Paper: US EPA; Glass: Glass Packaging Institute; Rubber: US Tire Manufacturers Association; Plastic: Association of Plastic Recyclers (APR) and the American Chemistry Council (ACC).
What are the different ways of recycling?
Throwing things away is a bad habit; recycling them is a good habit. Recycling isn't all that difficult: it's simply a matter of changing your habit. Practically speaking, recycling happens in one of two ways. Either your local government authority arranges a door-to-door collection (this is sometimes called curbside recycling) or you take your recycled items along to a local recycling center and place them in separate containers.
Photo: A curbside recycling service in England. Householders fill a large plastic box with mixed material for recycling, without sorting it out, and leave it outside their home. Items are sorted out at the curb into separate bins inside the truck, which has completely open sides for ease of loading and unloading.
The essential difference between a bag of trash and a bag of valuable, recyclable waste is that the trash is all mixed up together and the recyclable waste is sorted out and separated. If you have a curbside recycling scheme, you may be given a recycling box into which you can place certain types of waste (perhaps metal cans, glass bottles, plastics, and newspapers) but not others. When the box is collected, it might be sorted out at the curb. People on the truck will take time to sort through your box and put different items into different large boxes inside the truck. So, when the truck arrives at the recycling station, the waste will already be sorted.
Alternatively, you may see your whole box being tipped into the truck without any kind of sorting. The truck then takes your waste to a different kind of recycling station called a MURF, which stands for Materials Recycling Facility (MRF), where it is sorted partly by hand and partly by machine (this type of recycling is also called single-stream or comingled). If you don't have curbside recycling, it helps to sort out your waste and store it in separate bags or boxes before you take it to the recycling center. (For example, you could wash out food tins and glass bottles and keep them in separate plastic bags.)
Which materials can be recycled?
Most things that you throw away can be recycled and turned into new products—although some are easier to recycle than others.
Kitchen and garden waste
You can recycle up to half your kitchen and garden waste by making your own compost—a rich, crumbly, earthlike material that forms when organic (carbon-based) materials biodegrade (are broken down by worms and bacteria). Compost is great for using on your garden: it returns nutrients to the soil that help your plants to grow. Making your own is much cheaper than buying compost at a garden center; it's also better for the environment than using peat, which is a threatened habitat. To make compost, you will need a compost heap or a large container of some kind in your garden or yard. Composting is obviously much easier if you have a garden than if you have an apartment on the 23rd floor of a skyscraper! But even in cities, some authorities arrange collections of biodegradable waste and make compost at a central location. It can take anything from a few months to a year or more for waste to rot down and turn into compost. Generally, you need to add an equal mixture of "greens" (vegetable scraps, dead flowers, grass cuttings, and so on) and "browns" (torn up cardboard, small twigs, shredded paper, and that kind of thing).
Paper and cardboard
Photo: Shredded paper, bagged up and awaiting recycling. Photo by Ron Fontaine courtesy of US Navy.
In the early 1970s, photocopier manufacturers got scared that we would stop using paper and turn into a "paperless society." Not much chance of that! Over four decades later, the bad news is that we're producing more paper than ever before. But the good news is that we're recycling more as well. Unlike some materials, paper can be recycled only so many times. That's because it's made from plant fibers that become shorter during paper-making. When they're too short, they no longer make decent paper. In practice, this means some new paper always has to be added during the papermaking process.
One problem with recycling paper is that not all paper is the same. White office printer paper is made of much higher quality raw material than the paper towels you'll find in a factory washroom. The higher the quality of paper waste, the better the quality of recycled products it can be used to make. So high-grade white paper collected from offices can be used to make more high-grade white recycled paper. But a mixture of old newspapers, office paper, junk mail, and cardboard can generally be used only to make lower-grade paper products such as "newsprint" (the low-grade paper on which newspapers are printed). Corrugated cardboard (which is held together with glue) is harder to recycle than the thin cardboard used to package groceries.
Waste documents are usually covered in ink, which has to be removed before paper can be recycled. Using bleach to de-ink papers can be an environmentally harmful process and it produces toxic ink wastes that have to be disposed of somehow. So, although recycling paper has many benefits, it comes with environmental costs as well.
Photo: Collecting aluminum cans for recycling. The next stage is squashing them into bales so that they take up less room. Photo by Denise Emsley courtesy of US Navy.
Most of the metal we throw away at home comes from food and drink cans and aerosols. Typically food cans are made from steel, which can be melted down and turned into new food cans. Drinks cans are generally thinner and lighter and made from aluminum, which can also be recycled very easily. Mining aluminum is a very energy-intensive and environmentally harmful process. That's why waste aluminum cans have a relatively high value and why recycling them is such a good thing to do.
People have been reusing this traditional, sustainable material for as long as human history. Waste wood is often turned into new wooden products—such as recycled wooden flooring or garden decking. Old wooden railroad sleepers (now widely replaced by concrete) are sometimes used as building timbers in homes and gardens. Waste wood can also be shredded and stuck together with adhesives to make composite woods such as laminates. It can also be composted or burned as a fuel.
Photo: Glass is loaded into a crusher to compact it ready for recycling. Photo by A. Sanchez, courtesy of Defense Imagery.
Glass is very easy to recycle; waste bottles and jars can be melted down and used again and again. You simply toss old glass into the furnace with the ingredients you're using to make brand-new glass. Bottle banks (large containers where waste glass is collected) were the original examples of community recycling in many countries.
Waste oil from truck and car engines causes huge environmental problems if you tip it down the drain. It pollutes our rivers and seas, the wildlife that depend on them, and even the water we drink. If you take your waste oil along to a recycling center, it not only keeps our waterways clean—it can also be reprocessed into new products such as heating oil. Waste vegetable oils (made by frying food, for example) can be turned into a useful kind of vehicle fuel called biodiesel.
Photo: Disposable bottles and other containers are typically collected together, but they have to be carefully sorted into different kinds of plastic before they can be recycled. Photo by John Gordinier courtesy of US Air Force.
Of all the different materials we toss in the trash, plastics cause by far the biggest problem. They last a long time in the environment without breaking down—sometimes as much as 500 years. They're very light and they float, so plastic litter drifts across the oceans and washes up on our beaches, killing wildlife and scarring the shoreline. The only trouble is, plastics are relatively hard to recycle. There are many different kinds of plastic and they all have to be recycled in a different way. There's so much plastic about that waste plastic material doesn't have much value, so it's not always economic to collect. Plastic containers also tend to be large and, unless people squash them, quickly fill up recycling bins.
All told, plastics are a bit of an environmental nightmare—but that's all the more reason we should make an effort to recycle them! Different plastics can be recycled in different ways. Plastic drinks bottles are usually made from a type of clear plastic called PET (polyethylene terephthalate) and can be turned into such things as textile insulation (for thermal jackets and sleeping bags). Milk bottles tend to be made from a thicker, opaque plastic called HDPE (high-density polyethylene) and can be recycled into more durable products like flower pots and plastic pipes.
Another solution to the problem could be to use bioplastics, which claim to be more environmentally friendly.