• Ask students to work with the person sitting next to them to create a list of things that can and cannot be recycled. Ask them to categorize their lists, and have a few students share with the class. Have students use a T-chart.
• Place an assortment of items that can and cannot be recycled at the front of the room. Suggested items may include: glass, plastic, mixed paper, metal recyclables, corrugated cardboard, wax-coated boxes (such as an ice cream container or fast food to-go cup), batteries, papers such as envelopes with windows, papers with staples, some containers that still has food in them, a clean pizza box, and heavily greased pizza box that may still have food in it, batteries, light bulbs, paint cans and more. Pictures also work if actual materials cannot be collected. Ask students to add to their T-chart they started in step 1.
• Have students read the following article and add to or modify their T-charts. The American Recycling Business: Web Link - The American recycling business is a mess: Can Big Waste fix it? . Have students briefly discuss what some of the major issues in recycling are today. They can think of the entire recycling industry as a system that balances resources, economics, technology, human nature, policy . . . etc. Spend a little time asking students to rephrase what the article is saying. What is the “perfect storm”? According to the article, what are the current challenges that are impacting the way this system works? You may want to display a class list of ideas.
• Explain that they are going to focus on one of the challenges identified in the article: single-stream recycling and contamination. Explain they will examine one commodity more closely - paper - and some of the challenges associated with recycling it. Have students generate a class list of all the things students can think of that might be considered “contaminants” in paper recycling. Another way to think about this is, what kinds of things might have to be removed from paper in order to successfully recycle it and be able to make new, quality paper? List might include: staples, paper clips, inks, dirt, liquids, oils, grease from food or other dirty containers that are thrown into the same bins, colored paper . . . etc.

Engineers are always trying to come up with better ways to recycle materials. New ideas can make recycling less expensive, more efficient, safer, and more environmentally friendly. In this activity, you will be challenged to engineer a way to remove a contaminant from a batch of paper during the recycling process. You will then consider how this method might work on a larger scale in an actual recycling plant.

Materials:

• Device with internet access
• Student Data Sheet (printable PDF or copy and paste into an electronic document)
• Fine-meshed screen
• Large tubs
• Blender
• Vinyl gloves (Rubber or latex possible but must confirm no latex allergies)
• Rolling pin and/or iron
• Felt
• Large sponge
• Liquid starch
• Large bowl
• Gloves (optional)
• Newspaper
• Paper recycling
• Used envelopes with windows
• Paper recycling with staples
• Other materials, as determined by students

Safety Notes:

• When using technology, engage in safe, legal, and ethical behavior; this applies to devices (hardware), application or programs (software), and interactions with others.
• There are no anticipated physical safety risks associated with this Activity.

Part 1: Make Paper

• Discuss the information in the introduction with your class. Include in your discussion the idea that contaminants can limit the amount of paper that can be recycled.
• Divide students into small groups and distribute the Instructions for Making Paper handout to each student.
• Walk students through the process of making paper.
• Give students used paper to be their source for the paper they will make. Try to use paper that does not contain a lot of ink (very lightly used). Do not use newspaper for this step. Groups will use the piece of paper they make from this batch as their control so they understand the type of quality the in-classroom paper-making process is capable of producing (the paper will not look like commercial, white paper).
• Have students complete Part 1 of the activity.
• Some of the characteristics of good paper that students may identify is its strength (strong enough to write on without tearing), its thinness, and its light color, which allows writing to show up more easily.
• Note that students are likely to create imperfect paper to begin with. If time permits, allow them to experiment a bit and make several pieces of paper. They will not be able to produce paper of the same quality as paper you can buy, and that is fine. The purpose of this step is to give them practice making paper, and to give them a realistic idea of the quality of paper they can produce, which should inform the quality criteria they set for their paper in part 2.
• To prime students for the next part of the activity, discuss how the paper they were able to make differs from the printer paper they examined in the first part of the activity.

1. Examine a few different kinds of paper. List some characteristics that good paper shares.
2. Follow the instructions on the Instructions for Making Paper to make a new piece of paper from the used paper your teacher supplies. You may need to make a few pieces before you get one that has some of the characteristics of good paper that you identified.

Instructions for Making Paper

Grace, each of the numbered lists below should have continuous numbering instead of being separate lists.
Gather and Prepare the Materials

1. Cut the fine-mesh screen to a size that will easily fit in the large tub. You do not need to make the screen as large as the tub. The ideal size for this activity is about the size of a large post-card.
2. Cut the felt into two equal pieces, each slightly larger than your screen.

Prepare the Source Paper

1. Tear the paper into small pieces.
2. Soak the paper in warm water for at least one hour. For best results soak overnight.

Create the Paper Pulp

1. Place the soaked paper in a blender, filling it about a quarter of the way.
2. Add enough warm water to the blender to fill the blender halfway.
3. Blend the water and paper mixture on slow. Gradually increase the blender speed and blend until you have a paper pulp about the consistence of watery oatmeal. If the blender seizes, you can add a small amount of water.

Make the Paper

1. Fill the large tub halfway with water.
2. Place the fine-mesh screen at the bottom of the tub.
3. Add pulp to the tub and mix it into the water. The more pulp you add, the thicker your paper will be. Remove any large clumps of pulp.
4. Add two teaspoons of liquid starch to the tub and stir.
5. Slowly lift the screen from the basin, gently shaking it to even out the paper pulp on the screen. You may need to support the screen underneath as you lift it out of the tub.

Dry and Set the Paper

1. Hold the screen over the tub and let any excess water drip back into the tub.
2. Place a piece of felt slightly bigger than the screen on a flat surface. Lay the screen with the paper pulp still on it on top of the felt and cover it with another piece of felt.
3. Iron the top piece of felt on a low setting. Alternatively, roll over the felt with a rolling pin. This method will take significantly longer to dry.
4. When the paper is dry enough, but not completely dry, remove it from the screen and felt. Place it on a smooth, flat surface, and roll over it with a rolling pin. Flip the paper over and repeat on the other side. Note that you can skip this step, but rolling the paper in this way will make the final product smoother.
5. Allow your paper to dry completely before using it.
6. Trim the edges if desired.

Part 2: Engineer Paper

• Make sure each group has a copy of the Instructions for Making Paper and Paper Engineering handouts. 
• For this part of the activity, give students some of the same source paper you used in Part 1. In addition, include paper with a contaminant. Possible contaminants include staples, paper clips, plastic windows in envelopes, ink, and oil (to mimic grease from foods or other sources).
• Have students complete Part 2 of the activity.
• Have students follow the engineering process (see activity section) closely. Sometimes they will want to jump ahead and just try things. Following a methodical, thoughtful process helps them to better identify ways to improve their idea and to be able to repeat their process aside from intentional changes. It is also important that the students have clear and realistic quality criteria they want to meet and specific ways to test for these goals. This criteria should be based on the paper they made in part 1.
• As students are developing their plans, remind them that it is not acceptable to manually remove contaminants (i.e. pick out staples). The way this actual process might work changes with scale. What we can do in our classroom may look quite different in a large-scale recycling operation, where manually removing contaminants is not practical. Have students consider this. There may be some limitations to their models, therefore, in class, but they can think about what this might look like on a much larger scale.
• Students can conduct research by looking up information or by experimenting with materials, but they should not carry out a full test of their ideas during the research phase. For example, students might test to see if staples are attracted to magnets, but they should not mix pulp and try to use a magnet to remove the staples. This is a place where students often take a shortcut, so monitor this step carefully.
• Check students’ plans before allowing them to begin creating and testing their solutions. Look for safety issues and unrealistic time or materials needs. As long as students’ plans are safe and feasible to carry out and follow the rules of the challenge, allow them to proceed, even if you don’t think their idea will work. Avoid advising students about ways to improve their ideas. The point of the activity is to try, fail, and try again.
• Re-engineering their ideas is key to the engineering process. However, if time does not permit students to engineer and test multiple times, they can plan changes and additional testing procedures without carrying them out. Even if students’ attempts were successful, they can still think of ways to improve their design to make it more efficient, less expensive, etc.
• When students have completed the project, have them reflect using the Reflect and Apply questions. Use these as the basis for discussing the process as a class. Tie the activity back to paper recycling, the importance of recycling, and the room for constant improvement in recycling methods.
  

1. Again, follow the instructions on the Instructions for Making Paper handout to make a new piece of paper from the used paper your teacher supplies. This time the used paper will contain contaminants.
2. Your teacher will assign you one type of contaminant. Engineer a way to remove that contaminant at some point in the paper-making process. You may not remove the contaminant directly by hand.
3. Use the data sheet provided to follow the steps in the engineering process and to document your work and ideas.
4. Be prepared to share your results with the class. As a team, discuss how successful your methods were based on evidence (any challenges you experienced during the process, how much time it took, and the quality of the resultant paper), and what future improvements you could make.

Part 3: Findings & Analysis

• Once students have made their second piece(s) of paper, have the class do a gallery walk. If each team experimented with a different contaminant, have students indicate what contaminant they were assigned. You might have students create labels. At this point in time, students will be able to see the effects of heavy ink (if a team was assigned this) on the quality of the paper, and will be able to consider that when looking at their own results. The gallery walk itself should be done fairly quickly.
• Have students share their methods and findings with the class. They should explain what their contaminant was, what they did to remove it, how successful they felt they were, and if there is any evidence of the contaminant left in the paper they made. They should also describe any modifications they would make if given the opportunity to try again, and explain how this could work on a larger scale in the recycling plant.
• Have students read the article, Contamination in Paper Recycling: Web Link - Contamination in Paper Recycling . Then pass out the Residential Curbside Recycling Guidelines. Have students compare their original T-charts they made at the very beginning with the lists in the guidelines note any items they may have mislabeled. Discuss what items surprised them and why? Have students focus on the first rows - paper and cardboard. Discuss that people have engineered methods for safely removing some of the contaminants, and paper recycling plants can safely remove items such as plastic windows, staples, and ink. Some of the methods students came up with in class might actually mimic the real methods found at these plants. Paper with these items can go straight into the recycling bin. Other contaminants, however, such as grease, food, and wax, can ruin batches of paper and should be kept out of the recycling bin.
  

1. Lay out the paper you made in round 2 with a label indicating the contaminant your team experimented with. Walk around the room to view the class results. Be sure to notice the effects of heavy ink (if a team was assigned this) on the quality of the paper if your source paper also had amounts of ink.
2. Briefly share your methods and findings with the class. You should explain what your contaminant was, what you did to remove it, how successful you felt you were, and if there is any evidence of the contaminant left in the paper you made. Describe any modifications they would make if given the opportunity to try again, and how this might work in a large-scale operation.
3. Read the article, Contamination in Paper Recycling: Web Link - Contamination in Paper Recycling  and the handout called Residential Curbside Recycling Guidelines. Compare your T-chart to the items listed on the Residential Curbside Recycling Guidelines. These guidelines are very general, and might differ from your town’s guidelines. Focus on the first rows - paper and cardboard. Today, paper recycling plants can safely remove items such as plastic windows, staples, and ink. Paper with these items can go straight into the recycling bin.
4. Other contaminants, however, such as grease, food, and wax, can ruin batches of paper and should be kept out of the recycling bin. Make final adjustments to your T-chart.

Reflect and Apply:

• Was your idea successful? Did it produce paper free of contaminants that met your criteria? Answers will vary.
• What would you have done differently throughout the process? Answers will vary.
• Do you think that your method could be fully successful given more time to develop it? Why or why not? Answers will vary.
• How might a recycling plant be able to replicate your methods on a much larger scale? Do you think it would work? Explain why or why not. Answers will vary.
• With single stream recycling, consumers can now throw all of their recyclables into one bin, without having to sort the metals, plastics, and paper separately. What are some the negative impacts of this practice? Students can discuss how containers with substances still in them - soiled with anything from food to chemicals- often end up in the bin and can leak out onto the paper. Take-out containers or pizza boxes with food still inside can make their way into the bins. Glass can also be thrown in and break, making entire batches hard to sort and separate. Students might also talk about how single-stream recycling might promote laziness and/or “ambitious” recycling, both of which results in lots of items that cannot actually be recycled ending up in the bins. This, in turn, has other implications. For example, contaminants like plastic bags can cause whole recycling facilities to shut down for workers to remove and cut away the bags off the machinery. This method does not result in the highest quality of recyclables, and so, in the long run, not as profitable.
• Why do you think many areas have moved toward having one curbside recycling bin despite the negatives you may have identified in question # 5? Students might talk about up front costs being lower. Single-stream is easier for people so they are more likely to recycle - so even though not highest quality, has increased overall recycling rate. Other answers possible. Are there other positive benefits and do these outweigh the negatives? Explain your reasoning. Accept a variety of responses as long as they are based on reasoning.

• Identify some of the challenges of single-stream recycling.
• Define the problem of contamination in paper recycling, and design, test and refine an engineering solution (as time permits).
• Consider if and how their classroom model could transfer to a large scale recycling plant.
• Explain the inherent complexity of the recycling system and the relationships and trade-offs between making recycling easy for the consumer, helping the environment, producing high grade quality recyclable products, and economics.
• Identify specific ways they may be able to help reduce contamination in single-stream recycling.
  

Extension:

• Find out more about commercial paper recycling. What is the process? What are some common ways prohibitive contaminants are introduced into the process? What methods are used to remove those contaminants? Do these methods introduce any other problems, such as paper quality or environmental impact? Investigate to find out what paper recycling items are and are not allowed in your area. After your research, make recommendations to your school for ways to reduce contamination in your paper recycling. Use information from your research to back up your recommendations. Have students investigate what kinds of paper and cardboard can and can’t be recycled in their area. Have them make recommendations to their school for ways to reduce contaminants that are unacceptable in their paper recycling.
• Research what can and cannot be included in recycling bins in your area. Then research a few other cities’ recycling programs. Are there any differences in what can and can’t be recycled in these places? Why might those differences exist? Have students compare what can and can’t be recycled in their area with what can and can’t be recycled in other cities. Discuss why there may be differences. If glass can be recycled in one place, why might it not be recycled in another place?
• Compare the paper you made with your source paper under a microscope. What differences do you see in the fibers? You may also want to compare newsprint and printer paper under the microscope. How will the differences you see affect the quality of the paper? How will these differences affect the ability to recycle the paper again? Over time? Have students compare their recycled paper with source paper under a microscope, and describe the differences they see in fibers. How will these differences affect the ability to recycle the paper they made again? Over time?
• Journal Question: Discuss the inherent complexity of the recycling system and the relationships and trade-offs between making recycling easy for the consumer, helping the environment, producing high grade quality recyclable products, and economics. Do you think single-stream recycling should be kept or eliminated? Why or why not? What could you do to help eliminate contaminants from single-stream recycling in your own community? Ask students to explain the inherent complexity of the recycling system and the relationships and trade-offs between making recycling easy for the consumer, helping the environment, producing high grade quality recyclable products, and economics. Do they think single-stream recycling should be kept or eliminated? Why or why not? What could they do to help eliminate contaminants from single-stream recycling in their own community?

Additional Resources to Explore:

• Web Link - The American recycling business is a mess: Can Big Waste fix it?
• Web Link - Contamination in Paper Recycling
• Web Link - How to Make Paper
• Web Link - Everything You Need to Know About Paper Recycling