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7.1: Recycling in Human Communities

Difficulty Level: At Grade Created by: CK-12
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How can humans cycle their resources?

You've seen how materials cycle and recycle throughout biological communities. It is very important that we all remember the saying in Section 4: “You can't ever really throw anything away. There is no ‘away'!” What is on Earth now, stays on Earth. So we need to be careful how we use and reuse our resources. This section will help you discover some ways we can reuse and recycle our resources.

“Awareness is becoming acquainted with the environment, no matter where one happens to be.”

Sigurd Olson

quoted in The Earth Speaks

It has taken humans a long time to figure out that we need to do what biological communities have always done. Like biological communities, we need to recycle the materials that allow all living organisms on Earth to grow and survive. People in the United States are realizing that, when they throw things “away” they are merely putting them someplace else-usually where they don't have to see them. Unfortunately, most of the things that people throw away end up in a landfill somewhere. These items have been removed from their normal cycles and dumped so they are no longer serving any useful purpose.

What happens when you throw a piece of paper in the garbage can in your classroom? Does it magically disappear? No! If your school is typical of most schools in the United States, your paper goes on a very long and complicated journey.

Did You Know?
People in the United States produce 154 million tons of garbage every year-enough to fill the New Orleans Superdome from top to bottom twice a day-every day!

Let's follow that paper on its journey. First, your paper travels from the garbage can in your classroom to the custodian's garbage. Eventually it's dumped into the school's dumpster. The paper and everything else with it in the dumpster is picked up by a community garbage truck. The truckload of garbage is driven to a transfer station and emptied into an even bigger garbage truck. When the bigger garbage truck is full, it is driven to a clay-lined landfill where its load of garbage is emptied. At a typical sanitary landfill, the garbage is covered with soil or crushed rock at the end of each day. A landfill is covered with a clay cap when it's full so that rainwater can't get in. Rainwater must be kept out, because it could leach out chemicals from the garbage that might contaminate the groundwater beneath the landfill.

Figure 6.1 Throwing a piece of paper into a garbage can is just the first step of many until it is sealed in a landfill.

What Do You Think?
What sources of energy are used in the process of throwing away a piece of paper? Do you think that the energy sources are being used wisely? Explain your answer.

Does that sound like a long trip to you? Well, it is. And that piece of paper doesn't just take up space. No, disposing of that piece of paper also requires the work of many people. The school custodian, two garbage truck drivers, the people who work at the transfer station, the bulldozer operator at the landfill, and many other people are involved! And there's another problem with the way that paper was disposed of. That paper resource can't be used again. The paper was wasted when it could have been recycled and used again.

Landfills end the long trip your trash takes. There is no “cycle” for things put in a landfill. Many people think that landfills are wonderful places where garbage decomposes, and is turned into soil by decomposers such as worms and microbes. Unfortunately, that is not the case. Decomposers need water, sunlight, and air to decompose things quickly. The clay cap put on landfills to prevent groundwater contamination keeps out water, sunlight, and air. As a result, very little decomposition happens.

Figure 6.2 A landfill is more than a simple hole in the ground. What do you think are some of the things in this landfill that keep garbage from decomposing?

Draw a Paper Cycle Think about a pine tree in a forest. The paper in your notebook probably came from such a tree. Paper can be thought of as a resource that flows through the environment just as water, nitrogen, or carbon does. Is this flow a cycle? Draw a path showing the flow of paper from its source to where it ends up. How would the flow of paper in your drawing change if you lived in a community that recycles paper products? Add this to your drawing.

One self-named garbologist-William Rathje-has made a career of excavating (or digging up) landfills to see what actually happens to garbage in a landfill. He has found that newspapers do not decompose. So he regularly uses them to estimate the age of the garbage where he is digging. How do you think Mr. Rathje uses newspapers to estimate the age of the garbage? He has found hot dogs that look as if he could eat them. (But he doesn't, of course!) He has found five-year-old heads of lettuce that look no worse than lettuce that has been sitting in a refrigerator for a couple of weeks. But the hot dog and the lettuce were disposed of long ago. His discoveries have shown that little decomposition takes place in a landfill. Figure 6.2 illustrates how a landfill is constructed. You can see from the illustration that the clay and plastics used to enclose the landfill actually help to keep the garbage from decomposing quickly.

What do you think happens to paper bags in a landfill?

Activity 6-1: What's in Your Garbage and Where Does It Go?


What is in your garbage can? How many items in your garbage could be reused or recycled? Recent research indicates that people in the United States are creating more garbage than ever before. In this activity you analyze the types of things you throw away and where they go after you throw them away. Then you determine how you might reduce the amount of garbage generated.


  • A bag of typical garbage
  • Scale
  • Tape measure
  • Paper and pencil
  • Plastic bags
  • Cardboard box
  • Gloves
  • Calculator (optional)
  • Activity Report


Step 1 Weigh the bag of garbage on the scale and record this information on your Activity Report.

Step 2 Empty the bag of garbage into a cardboard box and record the volume of the garbage on your Activity Report. The volume can be determined by using the following equation. Volume = (length of box) × (width of box) × (height of garbage in box)

Step 3 Assume that this bag of garbage was produced in one day. Calculate the volume and weight of garbage produced by this household for a 30-day period. What would be the volume and weight of garbage produced during one year? Show your work and record the information on your Activity Report.

Step 4 Look at the garbage and discuss with your group how you could sort the garbage into categories such as plastic, paper, aluminum, and whatever other categories you can identify. Put the gloves on and sort the garbage into piles.

Step 5 Now remove all the materials that could be reused, recycled, or composted. List these items on your Activity Report. Then write how you think they could be reused or recycled.

Step 6 Calculate the volume and weight of the garbage after you have removed all of the items that could be reused or recycled. What would be the volume and weight for a 30-day period? What would be the volume for one year? Show your work and record the information on your Activity Report.

Step 7 Now choose one of the items you separated from the garbage because it could be recycled. Make a list on your Activity Report of the people who would handle it and the places it could travel on its recycling journey.

Here's another saying for you to remember. “Reduce, Reuse, Recycle!” We can partially avoid the problems landfills present by following this slogan. By following those three steps, in that specific order, we can significantly lower the amount of garbage that is thrown away. Let's examine each step, one at a time.

Overpackaging How can you change the amount of refuse that goes into a landfill? You can reduce the amount of waste you create by buying products that have less packaging or recyclable packaging. Bring in examples of products you think are overpackaged. Propose alternative packaging methods. Create a commercial to convince your Classmates that your alternative packaging method is better than the existing method. You may want to include posters or models to illustrate your point.


Reduce is the most important step because it is much easier to not make garbage than it is to dispose of it once it is made. Reducing the amount of materials we use helps in several ways. Energy isn't wasted in making the product. Time and energy aren't wasted in transporting the product to you. And time, energy, and space aren't wasted in taking it away as garbage to bury it in a landfill.

Let's look at a good example of a product whose use can be reduced or totally eliminated. Grocery stores use a lot of paper bags. Why chop down a tree, turn it into paper, and fashion the paper into a bag, just so you can take your groceries home from the store and throw the bag away? It's just as easy to use cloth grocery bags that can be washed and reused. Try to think of some other ways you can reduce the use of paper bags or eliminate their use altogether. Surprisingly, the people who work on solutions to the problems of landfills often ignore this strategy. Perhaps it is too simple. What do you think?

Select a packaged item from home or school that you think is overpackaged. Write a letter to the company that produced the item and suggest alternative packaging ideas.


Reuse resources, products, and materials. The next easiest step in reducing the wastes that go to landfills is to reuse the things you have. For example, you can take the grocery bags with you the next time you go shopping, and reuse them. You can also save the bag you got at the grocery store and use it to take your lunch to school. You accomplish two goals at once! You are reducing the amount of disposable items that you are using by not buying manufactured lunch bags, and you are reusing bags that you already have!

Did You Know?
One dollar out of every eleven dollars that people in the United States spend on food goes for packaging. In fact, we spent more on the packaging for our food last year than American farmers received in net income.


The last step is not the easiest step, but is very important to conservation and keeping our Earth healthy. Recycle the wastes you produce. This task is harder than reducing or reusing products. Recyclable items have to go through several steps and processes. Recycled wastes have to be taken to a recycling collection center. From there they are transported to a recycling plant and remanufactured into new products. Then the new products are returned to a store for someone to buy again. Think about it. You can recycle a paper bag by taking it to a recycling center. There it can be prepared for a paper recycling plant. The paper bag is turned into a new paper product and sold again. It seems a lot simpler and more considerate to our environment to not have picked up the bag in the first place.

Most Common Recyclables

  • Newspapers
  • White office paper
  • Corrugated cardboard
  • Magazines not coated with clay (not glossy)
  • Aluminum cans
  • Steel cans
  • Glass (must be sorted by color)
  • Plastics are coded. (See Figure 6.4.)

Figure 6.3 You usually have to sort recyclable items when you prepare them for recycling.

Recycling is an important option for reducing the amount of waste you send to a landfill. Many communities in the United States have recycling programs that can handle most of your household wastes. The most commonly recycled materials are aluminum, steel, glass, newspapers, office paper, and some plastics.

Did You Know?
It takes an entire forest (over 500,000 trees) to supply people in the United States with their Sunday newspapers every week. Newspapers take up almost 25 percent of the room in a typical landfill in the United States!

In order for wastes to be recycled, they have to be sorted into their different types. You can't turn a garbage can full of assorted garbage into recycled paper. But you can turn a stack of newspapers into recycled paper. Some cities collect recyclable materials all mixed up together, and the materials are then sorted mechanically or by people. However, most cities with recycling programs require that the people who are throwing things away do the sorting. Perhaps you have separate bins for bottles, cans, and paper in your kitchen because you recycle already.

Did You Know?
  • Making aluminum products from recycled aluminum cans uses 90% less energy than making aluminum products from scratch.
  • The energy saved from recycling one glass bottle could light a 60 Watt bulb for four hours.
  • Recycled plastic can be used to make products such as plastic lumber and fiberfill sleeping bag insulation.

Recycling your wastes can be simple and fun. But before you start setting up bins and sorting everything from foil balls to toothpaste tops, you should check with your local recycling program. The people at the recycling program probably want you to sort your recyclables in a very specific way. Their goal is to have you sort the recyclables in a way that is useful for the people in your area who use those recyclables to make new products.

The world of recycling changes constantly. Your community might recycle some of the above-mentioned things, all of these things, or maybe even more than what was described here. Be sure to check with your local recycling program so that you can save energy, save resources, and keep your local landfill from filling up quite as fast.

Figure 6.4 Plastics are coded 1-7. Objects coded 1 are easy to recycle. Objects coded 2-6 are increasingly harder to recycle. Objects coded 7 cannot be recycled at all. Mixing the coded objects can spoil an entire batch at a recycling plant.

Name ten things that are thrown away but aren't on the list of most common recyclables.

There is one type of material you may be able to recycle completely in your own home. Yard waste, such as grass clippings and leaves, are biodegradable (by-oh-dee-GRAY-duh-bul) materials. Biodegradable means that decomposers can turn them into soil fairly easily. You can recycle yard wastes by building a compost pile in your yard.

Review Questions

  1. Why do people who work on waste disposal say that there is no “away”?
  2. What are the three steps you can follow to limit the amount of garbage that you send to a landfill?
  3. Why is it important to properly sort items for recycling?
  4. What is meant by biodegradable? Give two examples of biodegradable items, and explain why each is biodegradable.

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Date Created:
Feb 23, 2012
Last Modified:
Aug 06, 2016
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