Eliana Schwartz
ES 220
Professor Molitor
April 28, 2013
Vermicompost Biology Intern Final Report
Whitman College produces 4,000 pounds of food waste each week. In an attempt to
lower the amount of waste sent to the landfill, and thereby enhance the sustainability of
Whitman’s campus, a student club called Campus Climate Challenge began researching
composting methods in 2010. Initially, composting was occurring on a smaller scale as Green
Leaders, another environmental club on campus, set up compost tumblers outside of the
residence halls. Unfortunately, this system was unsuccessful due to an excess of food waste and
inhibition of the decomposition process due to cold winter weather. This led Campus Climate
Challenge members to begin working with Bob Biles to select and implement an optimal
composting system for Whitman’s campus (Compost).
Vermicomposting appeared to be the best option. The students applied for and received
funding to purchase a worm-wigwam and 45,000 Red Wiggler Worms. Constructed and
established in the fall of 2011, a red shed behind Jewett dining hall now houses Whitman’s
worms in their wigwam. The Red Wiggler Worms are fed food waste from Jewett dining hall
and they will break down the food into vermicompost. This vermicompost will eventually be
used by the Physical Plant on campus (Compost).
Once it reaches full capacity, the wigwam will hold 105,000 worms and will process
more than 100 pounds of food waste each day. Unfortunately, the group faced a setback in the
spring of 2012 when, after following the advice of the wigwam vendor, 40,000 of the initial
45,000 worms died. The worms, searching for more oxygen in compost that was too compacted,
had fallen out of the bottom of the wigwam and died as a result of losing their essential moisture.
The group then consulted local worm breeder Barbara Newby who explained that the top layer of
compost should be turned after each feeding to prevent compaction and to keep the worms
oxygenated. Since then, the system has been functioning better and the worm population has
been steadily increasing. The worms are fed two times per week and shredded paper and peat
moss are added to the wigwam after each feeding. The compost is turned after food, paper, and
peat moss are added (Compost).
I became involved with the Whitman Industrial Composting Group in September 2012.
At this time, the emphasis was on increasing the worm population after the setback of the
previous spring. As the biology intern this semester, I am now a more integral part of the group
and I have worked to maintain worm health through proper feeding, turning, and regulation of
the worms’ temperatures with the goal of increasing the quantity of food that the system can
process and thereby producing harvestable compost for the Physical Plant. Furthermore, I aimed
to learn about the history of Whitman’s worm composter and understand the reasons for its
installation and to learn about the biology surrounding the composting cycle, including what
occurs within the bin and in the gardens where the compost is used. At the time I began, it was
also imperative that we find a more sustainable alternative to peat moss. Lastly, I worked to
weigh and record the food fed in order to the worms to track and document the total waste saved
by the industrial composter.
I began researching peat moss alternatives right away. Peat moss is used for retaining
moisture in the compost system. Worms breathe using the diffusion of oxygen through their skin.
Their skin must be moist, otherwise they will be unable to breathe. Thus, it is essential for the
system to have some component that holds moisture. In my research, I found many alternatives
to peat moss. Each option had potential problems, however we selected coconut coir as the most
suitable alternative. We have factored the cost into our budget for next year and we will purchase
the coir once we run out of peat moss.
This semester has been largely impacted by our trip to Walla Walla Community College.
WWCC has the same composting system, albeit one that is much more successful. They have
already harvested finished compost multiple times and their wigwam is much closer to capacity
in terms of worm population and food waste processed. We had been hoping to visit them for
some time but they were difficult to reach. Finally, we were able to see their system and meet
with Ben, the head of their composting system. He walked us through his feeding process, which
differed slightly from ours. First, he adds ground eggshells to provide calcium and fiber for the
worms. He also adds mulched leaves and shredded newspaper for moisture retention. He
efficiently chops food with an edger in a bucket instead of manually chopping all of the food on
a cutting board as we do. He mixes the food, newspaper, eggshells, and leaves in a soil mixer for
ten minutes and then dumps it in the bin and turns his compost. He adds huge quantities of food:
the worms will eat some and the rest will naturally decompose, producing heat that encourages
the worms to eat more and breed faster. Ben was very friendly and offered us the use of his
industrial paper shredder and eggshell grinder for our use. Overall it was a very informative and
inspiring visit.
We were energized by seeing the success of the wigwam at WWCC and began planning
to change our routine to replicate Ben’s. We experienced some tension within our group when
some members expressed discomfort with following Ben’s advice because it would necessitate
ignoring Barbara Newby’s advice. Barbara had been very helpful over the past year and it felt
rude and disloyal to ignore her advice. Ultimately, we decided upon a combination of the two
programs, increasing food quantities while continuing to use peat moss and newspaper as per
Barbara’s instructions.
We left for spring break on a high note. The worms were processing upwards of 60
pounds a week, fed twice weekly. We were adding add newspaper shreds and ground eggshells
on Ben’s recommendation. We had harvested a small quantity of compost. To remove the worms
from the harvest, we had followed Ben’s advice and made small piles of compost on a tarp in the
shed. Within a day, the worms crawl down to the bottom of the pile. The worms can then be
removed from the harvest and we can begin the process of drying out the compost before it is
ready for the Physical Plant. We will dry out the compost in a club member’s backyard on a tarp.
Upon returning from spring break, we found the system in a state of disrepair. There was
a huge quantity of water beneath the wigwam with drowned worms floating in it. The compost in
the wigwam looked moist but not hugely problematic. Unsure of what had caused the major
leakage, Meghan and I chose not to feed the worms that day. Instead, we added huge quantities
of newspaper, hoping to absorb the excess liquid. After a smelly and rather disgusting cleanup,
we still do not know what caused the problem but we have three hypotheses: 1) we increased
food quantity without proportionally increasing paper quantity so the extra liquid from the food
was not being absorbed and/or 2) fluctuating temperatures over spring break disturbed the
biological processes that occur and/or 3) we harvested too soon with Ben so the castings at the
bottom of the wigwam were not compacted enough to absorb and retain the moisture from the
food.
We have moved forward and the system is now looking fantastic. Aware of the
importance of the paper shreds, we have increased the amount of paper shreds added during the
feeding process. The worms are fed between forty and sixty pounds weekly and we hope to
gradually increase this quantity so that we do not experience any more setbacks. We have
learned that patience is extremely important in this work; if we attempt to rush the biological
processes that occur, we will only disrupt the balance of the system. The major leaking and the
death of many worms was unfortunate but we have learned much from the experience. The
worms are looking healthy, the soil inside the wigwam is exactly what we hope to produce, and
we are becoming more and more knowledgeable about vermicomposting.
In further progress, we applied for and were granted funding from ASWC’s Green Fund
for tools such as an edger for cutting food, a sifter for removing the worms from the harvested
compost, and a thermometer with a longer stem that can more adequately measure the
temperature of the wigwam. Whitman’s vermicomposting system has greatly improved over the
past couple of months and prospects are bright in terms of its ability to reduce campus
contribution to land fills and provide the Physical Plant with nutrient-rich compost to be used on
campus.
I am glad to be a part of this group and involved in waste reduction on campus.
Unfortunately, few students on campus know about the wigwam. I think being a member of the
Whitman Industrial Composting Group is an excellent opportunity to learn about waste reduction
and vermicomposting as well as engage in an important and often overlooked dialogue about
campus waste. It is also a shining example of student initiative and the opportunities on campus
to effect change. The biology internship is a unique and rewarding experience. It calls for handson learning and applying classroom knowledge to the real world. My understanding of the
composting process has greatly increased as I work with directly with the worms and I have a
newfound sense of efficacy. Overall, this internship is an excellent way to be an integral part of
this hard-working, environmentally conscious group.
Works Cited
Bourdon, Ludovic. "Peat Moss Vs. Coconut Fiber ." World of Worms. N.p., 11 Aug. 2011. Web.
26 Feb. 2013. <http://www.worldofworms.com/peat-moss-vs-coconut-fiber/>.
"Compost." Whitman College. N.p., n.d. Web. 26 Feb. 2013. <http://www.whitman.edu/aboutwhitman/campus-sustainability/recycling-and-compost/compost>.
Worm Biology 101." Sierra Worm Compost. N.p., 5 June 2012. Web. 26 Feb. 2013.
<http://www.sierra-worm-compost.com/worm-biology.html>.