Trash Audit Results: April 25, 2005
Clark’s first ever Trash Audit was performed on April 25th, in honor of
Earth Day. The purposes of the Trash Audit were to a) provide a snapshot of our
solid waste composition in terms of general types and quantities; b) help
determine what percentage of our trash could be recycled instead of being
thrown away; and c) generate increased awareness of our waste generation here
on campus.
What was done?
With the help of our custodians, the morning trash from four buildings
was diverted from dumpsters around campus. The four buildings were chosen to
provide a snapshot of waste from academic, office, residential, and social areas
of campus. A total of nine bags of trash were collected for the audit. While the
original intent of the audit was to be able to analyze waste from each of these
areas separately, low volume from one building prohibited an accurate
measurement of the weight of each category of waste from that location, and the
buildings were analyzed together to capture that building’s contribution to the
waste stream.
All trash collected was weighed, to provide a total weight of trash being
sorted. Then, each bag of waste was opened, and its contents sorted into the
following categories: trash; recyclable bottles & cans (accepted in Clark’s
recycling program); recyclable plastics (items not currently accepted in Clark’s
recycling program, such as clamshell takeout containers); food waste and
compostables (including paper items not accepted in Clark’s recycling program
such as paper plates, cups, napkins, and paper towels); cardboard and
boxboard; and mixed recyclable paper.
Once sorting had concluded, each category of sorted waste was weighed
to the nearest pound using a scale. The weight of the sorting containers was
subtracted to yield net weight of the sorted waste.
What were the results?
Category
Unsorted Trash
Sorted Trash
Recyclable Bottles & Cans
Recyclable Plastics
Food Waste/Compostables
Cardboard & Boxboard
Mixed Recyclable Paper
Weight
69 lbs
20 lbs
6 lbs
5 lbs
18 lbs
3 lbs
17 lbs
Percentage
100%
28.9%
8.7%
7.2%
26.0%
4.3%
24.6%
Percentages may not add to 100% due to rounding.
What must we take into consideration when interpreting these results?
The primary consideration is that the waste that was sorted may not have
been representative of Clark’s waste stream. A number of potential reasons for
this exist, including a) waste was collected from specific buildings instead of
directly from dumpsters and compactors, which could have yielded a better
representation of the trash from a wider variety of buildings; b) the sort was
conducted early in the week and the trash sorted was collected early in the day,
therefore creating a potential skew in the types of waste examined since waste
generated over the weekend can have slightly different components than that
generated during the week; c) the sort was conducted at the end of the
semester, when, due to cramped schedules, recycling may not be as high a
priority as it would be during a less busy time of the year; d) the volume sorted
was low, decreasing the likelihood that the combination of bags was
representative of the location where the trash was generated. It is also
noteworthy that the waste collected for the audit did not include waste from any
of the Bon Appetit kitchens; therefore our results for compostable waste may be
skewed.
What do our results mean?
Perhaps the most obvious result of the trash audit is that as a campus, we
must put more effort into recycling paper. Even if the results are not completely
representative of our waste stream based on the considerations above, our
current recycling program clearly could capture a significantly greater amount of
paper. We do, however, seem to be capturing cardboard fairly well, as indicated
by the lower percentage overall of this material found in the audit; efforts to
capture cardboard should continue.
The audit also indicates that Clark’s bottle & can recycling program is
fairly successful at capturing those containers from our waste stream, an
unexpected conclusion based upon the knowledge that overall plastic beverage
container recycling has dropped nationally from about 53% in 1994 to 19% in
2003 (Container Recycling Institute); bottled water consumption has
skyrocketed in a few short years (3.3 billion bottles sold in 1997, 15 billion
bottles sold in 2002) (Container Recycling Institute); and one of the four
buildings audited does not have container recycling bins due to space
constraints. The recycling program should not take the subdued presence of
containers in the trash as an indication that further promotion and access to this
portion of the program is not necessary.
The percentage of non-recyclable plastics discovered in the audit was
lower than expected; indicating that expanding our program to include these
plastics should be a lower priority than other improvements.
The amount of compostable waste found during the audit was surprising,
considering that no waste was taken directly from foodservice. This result may
indicate that the next commodity to be added to the recycling program should be
compostable waste. As a side note, it would be interesting to separate this
waste further into categories of food waste and non-recyclable paper products
(paper towels, napkins, paper plates, cups, etc), to determine how inclusive a
composting program on campus should be (that is, which buildings we should be
collecting compostables from).
Overall, the trash audit has indicated that we certainly have some
improvements to make in our recycling efforts; a larger, more comprehensive
follow-up audit should be performed in the fall to improve upon the data
collected as well as determine if trends have improved.