School Waste Audit
Goal: Quantify the amount of waste being generated by school by category (reusable, recyclable, compostable, trash)
Objectives: Students will…
- Develop a scientifically sound plan to quantify school’s waste stream by category
- Collect and measure waste
- Classify waste into reusable, recyclable, compostable and trash
- Compare class study with statistics provided by waste hauler or school/district
- Extrapolate waste results over different periods of time
Materials: tarps, trash bags, rubber gloves, bathroom scale, large bins or trash cans, calculators
Advance Preparation: figure out who in your school students should ask for statistics on waste hauling and landscape waste, inform any necessary staff about your waste audit plans
Time Estimate: 3 days
1 class period for planning
1-2 class periods for collecting, sorting, measuring
1 class period for data analysis
School Waste Audit
Instructional Plan
Plan the Audit
Present students with the following challenge:
Figure out how much reusable, recyclable, compostable and landfillable waste is disposed of at school every day, week, month and year.
You can frame this as a question to answer using the scientific method or as the challenge stated above. You can do this planning as a large group brainstorm or break into small groups. It may make sense to do the general planning in a large group and then break into groups focused on specific tasks that need more detailed planning (ex. categorize, measurement, collection, sorting, data recording)
The students should lead the research design process but here are some tips to keep in mind.
- If they don’t want to collect ALL the waste from the school, they could collect a representative sample, which would mean thinking about the different types of rooms and the waste disposed of in them. Urge them to think through the spaces they do not use like admin offices and the kitchen in addition to classrooms, cafeteria, gym, hallway, library, etc.
- They may want to label the waste from different types of rooms so they can record the quantities separately, which will be helpful for their calculations.
- Trash is typically measured by both weight and volume. Encourage students to discuss what measurements will be meaningful to their research and why and how they can make their measurements as accurate as possible.
- One option for quantifying cafeteria waste is for your students to sort waste as it is brought to the trash can which will avoid messy sorting later on.
- How will the students record their data?
- How can they find out how much landscaping waste is generated and what happens to it?
- Students will need to develop a list of all the materials they expect to encounter in the audit and which category they fall into so that everyone is sorting according to the same criteria. When surprise items come up, they can address how to sort them as a group or have a small subset of category consultants.
Who will you need cooperation from in order to conduct a successful audit (custodiams, teachers, cafeteria workers, administration, secretaries…) and how will you communicate your plans?
Conduct the Audit
How you coordinate the audit efforts will depend on the plan your students have developed, how many class sections you have working on this and how you wish to divide labor. If you have multiple classes you could have each of them conduct all steps in the process or you could get them to team up and divide the labor (ex. one class does cafeteria waste, another does classroom waste and they share the data).
Some tips to help your audit go smoothly.
- Sorting the trash can be messy business. Dumping it out onto a large tarp and sorting materials into bins from there can make it easier to sort quickly and minimize mess (make sure the bins are on the tarp as well!). If the weather is decent, you could even do this outside.
- If your students are measuring volume, make sure they are being consistent in how much they are compacting (or not) the waste.
- For weight measurements, remind them to subtract the weight of the empty container from the final weight.
- You may want to make signs for rooms from which you are collecting waste to remind custodians not to empty those containers: make sure you provide details about when you will be collecting the waste and take the signs down when you are finished.
Analyze the Results
Your students will be recording their data as they collect it. If your classes will be sharing data with each other, you should consolidate all of the data in one place so you can share it easily. Assist students through the process of extrapolating their data from their samples to the entire school building and from one day to a week, month and school year.
If you have not already, have the students collect information from the waste hauler or facilities manager about the amount of trash and recycling removed from the school and compare their calculations with the actual data.