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Trash Audits

Conducting a trash audit can be both fun and informative. A trash audit is essential because it helps a waste-free lunch committee determine where the bulk of the trash is coming from. It can help answer such questions as:

  • Is most of the waste coming from home or being generated through the school's hot lunch program?
  • Is there a difference in the amount of trash being generated by different age groups?
  • Are students using the recycling bins? If not, why not?
  • Can we reduce plate waste through composting?

Getting Started

As a committee you'll need to decide on the following:

  • How many trash audits you're going to do
  • When you're going to do them
  • Who's going to do them
  • How you're going to do them
  • Whether you'll continue to do them at regular intervals
  • How you're going to communicate with parents, faculty, staff, and students about the trash audits
  • What you'll do with the results you obtain

At Gateway School, for example, it was decided that three waste audits would be conducted, one before Earth Week, one during Earth Week, and one a month after Earth Week.

One parent on the committee volunteered to take responsibility for conducting the trash audit, and others on the committee agreed to help her. They then elicited the help of the school lunch aides and explained to them what they were doing and why they were doing it. (It should be noted here that at this point in the process most of the aides started packing their lunches in reusable containers!)

Since time was limited and a trash audit had not been conducted before, they decided to keep it simple. They're hoping to expand the scope of the trash audits. They'd also like to use the results of the trash audits in the classroom to teach not only planet ecology, but also math, graphing, estimating, charting, presenting information, and more.

Their simplified method took very little time and required little staff participation. They were concerned that the already overworked teachers and staff would resent having one more thing "dumped" on them, so the first year the committee decided to take sole responsibility for the trash audit. In the future they hope to have enough time so they can plan ahead and allow teachers to build planet awareness and waste reduction into their lessons from the start, or at least make sure that students see the connection between what they're learning and how they can live more responsibly.

The trash audit was conducted by grade level. Two grade levels were scheduled per day (approximately 80 children each day) because only two adults were available to work on the audit each day. A schedule was created and distributed to the parent and staff volunteers. The leader of the group was there every day for consistency.

At Gateway School the students have a morning snack around 10:30 and lunch around 12:00. The classes are staggered for both so that the lunch area and playground do not become overcrowded. One of the kindergarten classes eats a group snack every day. All other students bring a daily snack from home.

An adult volunteer was present during both snack time and lunch time to make sure that all of the trash was collected. The trash cans were taped shut so that students could not throw away their trash. Instead, each group was provided with a trash bag marked with their grade level. As students finished eating their snack, they threw their trash into the specified bag. When snack time was over, the bags were collected and saved so the lunch trash could be added later.

At the end of the lunch hour, each bag of trash was weighed. Then one adult volunteer worked with each group of students, sorting the trash into categories (see chart below) and counting the number of pieces of each type of trash. (Students were provided with disposable gloves--seconds--so that they would not have to touch the trash.) The categories they chose were:

Hot Lunch

Each group was provided with a table for tabulating their results. As they counted, they put a tick marks in the relevant category so that they could determine how many pieces of each type of trash they had collected. When they were finished, the recyclables were put in the appropriate recycle bins and the rest was taken out to the dumpster. (They did not include food waste in our audit.)

While the methods were not entirely scientific, they did compile the results for the students to see. The results were graphed by class and posted in the lobby as part of their Earth Week display. They enjoyed seeing the before and after results and were pleased to see that they had reduced their total lunch and snack trash by about 35%. Here's a chart which shows their waste reduction results by class.

Trash Audit Results


Pre-Earth Week Audit

Earth Week Audit

(in pounds)

Percent Change
Kindergarten 5 3/4 lbs
3 lbs
-2 3/4 lbs -48%
First Grade 2 lbs 1 3/4 lbs -1/4 lb


Second Grade 1 3/4 lbs 1 3/4 lbs 0 0
Third Grade 3 1/2 lbs 2 lbs -1 1/2 -43%
Fourth Grade 2 lbs 1 1/2 lbs -1/2 lb -25%
Fifth Grade 3 1/4 lbs 2 lbs -1 1/4 lbs -38%
Sixth Grade N/A On Field Trip N/A N/A
TOTAL 18.25 12 -6.25 -34.2%

For a description of another trash audit procedure, visit www.astc.org/exhibitions/rotten/audsch.htm.

Do you have some trash audit ideas or results you'd like to share?

Email them to us at info@wastefreelunches.org.