Posted by Eric Pallant, Department of Environmental Science, Allegheny College/updated 3 September 2002
Return to Compost, Compost syllabus
Compost, Compost,
We Love You
Kristine Bialy-Viau
Robin Boldosser
Dustin Eaton
Isaac Kerns
Jason Mease
Jacqueline Nameth
Laura Paich
Eric Pallant, Professor of
Environmental Science
Michael Shema
Justin Vernon
Summer, 2001
The Commonwealth of Pennsylvania
has approved a grant proposal for Allegheny College to receive an in-vessel
composter and other necessary components needed for a campus-wide composting
operation. Included in the grant,
besides the composter, are totes, a vehicle for tote transport, a Bobcat, a
chipper, a building extension with concrete pads and a ramp to house the
composter, electric, water, sewer, fencing and a shaker machine. The composter, which costs more than
$100,000, will arrive on campus in fall of 2001. The composter, which is roughly the size of a train car, is made
by Wright Environmental Management, Inc. in Ontario, Canada.
With the composter, Allegheny College will become more environmentally responsible by reducing the amount of waste it contributes to landfills and in the long run this process can financially benefit the college. The composter has the capacity to completely turn all biodegradable materials into compost in a matter of 28 days. Foodstuffs, grass clippings and other forms of leaf and yard waste, and various paper products will all go into the composter to be rendered into a usable, nutrient rich soil amendment. Before the composter arrives we have a great deal of preparation to do in order to ensure a smooth campus-wide compost operation. The following will illustrate this process and lay out some possible suggestions for Allegheny College.
The arrival of the composter will move Allegheny College in the direction of sustainability. Although it may not be the best way to manage our waste, it is undoubtedly more environmentally friendly than our current system. The composter will divert materials that would otherwise be going to landfills, and convert them into a rich soil amendment. In addition, if the implementation is coupled with a change in our current waste hauling contract, greenhouse gas emissions from transportation will be reduced.
The use of the composter may bring about a few economic benefits as well. The biggest economic benefit is contingent on switching our current waste-hauling contract. Seeing that the composter will divert a large amount of our waste stream, we will have less trash in the dumpsters. It would behoove Allegheny to switch its current waste-hauling contract to a per/cubic yard basis or to pay for the dumpsters to be tipped once they are full. Another economic benefit will come from the compost itself. Once the composter is up and running, Allegheny will be generating rich soil amendment to be used in flower beds and planting trees around campus. This added soil amendment will result in a reduction of costs for fertilizer and topsoil.
While there are a number of prospective savings to be had as a result of the use of the composter, a number of activities associated with the operation of this machine will represent added costs to Allegheny College as well.
The In-Vessel Composter requires manual operation on a regular basis, as well as personnel to transport compostable materials from the campus to the Robertson Field composting location. A new employee will most likely have to be hired, and this labor does represent an added cost to the college. Another cost associated with the implementation of the composter is that of maintenance. The composter requires water and electricity to do its job. These are both costs the college will have to incur annually. In addition, the totes used to transport the compostable materials up to Robertson Field will have to be rinsed out frequently, further increasing our water bill.
In examination of both the cost-savings and cost-additions associated with the operation of this machine, we argue that the ability of Allegheny College to save money as a result of the composter is entirely reliant on the renegotiation of the waste-hauling contract. The composter will divert a significant amount of our waste stream and we must take advantage of that. Capitalizing on this diversion requires the formation of a contract that bills Allegheny on either a per/cubic yard or per/pull basis.
In order to calculate the total weight of the compostable material located in the McKinley's dumpster it was necessary to weigh all the bags of compostable material located inside it. This task was done every night at 10:00 p.m. for seven straight days starting on February 19th, 2001, and ending February 25th, 2001. This required the cooperation of 5 - 6 persons per night, a bathroom scale, rubber gloves, dust masks, and rubber boots. All participating members were required to wear rubber gloves and dust masks. The weigh-in process began by designating people specific tasks, these included: a person to get in the dumpster to hand out the trash, a person on top of the dumpster to carry the trash to a person on the loading dock, this person handed the trash to a person standing on the standard dial bathroom scale, then the trash was passed to another person who would pile the trash aside, a recorder was also needed to write down all the information. Initially, the person standing on the scale was weighed to obtain the tare weight for each reading. When the person on the scale was handed a bag he would call out the combined weight to the recorder who logged all this information. Judgement of what was to be weighed was made by observing the contents through the clear bags. If the contents consisted of mainly McKinley's serveware then it was included in the survey. All other bags were set aside. Upon emptying the dumpster all the trash was then tossed back into the dumpster and the area was hosed down for sanitary purposes. The total weight was then calculated by summing all the combined weights and subtracting off the total tare weight. This process was repeated for an entire week to determine and compare the amount of waste produced each day (mainly weekday vs. weekend). Volume was calculated by multiplying the total volume of each bag (52 gallons) times the average percentage of waste per bag (40%) times the number of bags or [52 x .40 x # of bags = volume in gallons]. The average volume per bag was estimated from visual observation. We later took the volume in gallons and divided that by 202 which is the number of gallons in a cubic yard in order to calculate cubic yards of waste [volumes in gallons/202 = cubic yards]. To estimate the total amount of waste per year the number of cubic yards was multiplied by 30 which is the number of weeks in a school year.
The following week (February 26th through March 4th) the food waste from the Schultz and Brooks dining halls was measured. The amount of waste was based solely on weight and did not account for volume. However the waste was contained in 50-gallon garbage cans with 3 cans located in Schultz and 2 cans placed in Brooks. Measurements for Schultz were only taken once per day, Monday through Thursday, at 7:30 p.m. because they only serve lunch and dinner these four days. The waste was also measured Friday at 1:30 because Schultz only serves one meal this day. Collection for Brooks took place after lunch and dinner, Monday through Saturday, at 1:30 p.m. and 7:30 p.m. respectively. Sunday the waste was measured only once at 7:30 p.m. because only two meals (brunch and dinner) were served this day. To actually calculate the weight we used the bathroom scale that was mentioned previously and a platform constructed from two 2x4's and an 18" square sheet of plywood. The platform was placed on the scale then the garbage cans were loaded individually onto the platform. This allowed us to attain an accurate reading of the scale for each can. Each weight was recorded on a chart to keep track of all the numbers. Then the weights were added together to calculate the total weight of waste per dining hall. From the weight we needed to calculate the number of cubic yards. To do this we weighed three full 44-gallon garbage cans, then calculated the weight per gallon by dividing the can weight by 44 [lbs./44 gal. = lbs./gallon]. These numbers were then averaged to determine the average weight per gallon at 6.7 pounds. The combined weight from all three dining halls was divided by 6.7 to determine total gallons, then that number was divided by 202 to determine cubic yards [total lbs./6.7/202 = cubic yards]. There were no special dining events during our observation period. To estimate the total amount of waste per year the number of cubic yards was multiplied by 30 which is the number of weeks in a school year.
|
Results from the waste audit at
McKinley's, with bags at 40% full
|
Day |
Weight |
# of bags |
Volume |
Volume |
|
Monday |
677 |
60 |
1248.0 |
6.18 |
|
Tuesday |
430.5 |
41 |
852.8 |
4.22 |
|
Wednesday* |
1057 |
84 |
1747.2 |
8.65 |
|
Thursday |
725 |
53 |
1102.5 |
5.46 |
|
Friday |
668 |
52 |
1081.6 |
5.35 |
|
Saturday |
401 |
33 |
686.4 |
3.40 |
|
Sunday |
380 |
24 |
499.2 |
2.47 |
|
TOTALS |
4,339 |
399 |
7,218.1 |
36.13 |
*Wednesdays are stir-fry days, especially heavy waste days at McKinley’s.
Schultz and Brooks: 8.2 - 75 gallons/day; .04 - .32 cu.
yds./day
Food
scrap and food prep. audit
|
Day |
Location |
Weight |
Volume (gallons) |
Volume (cu. yds) |
|
Monday |
Schultz |
317 |
55.16 |
0.27 |
|
|
Brooks 1:30 –
2:00 PM |
245 |
42.63 |
0.21 |
|
|
Brooks 7:15 –
7:30 PM |
331 |
57.6 |
0.29 |
|
|
McKinley's
3:00 - 3:30 PM |
121 |
21.1 |
0.10 |
|
|
McKinley's
9:00 - 9:30 PM |
83 |
14.4 |
0.07 |
|
Tuesday |
Schultz |
265 |
46.11 |
0.23 |
|
|
Brooks 1:30 –
2:00 PM |
192 |
33.42 |
0.17 |
|
|
Brooks 7:15 –
7:30 PM |
321 |
55.85 |
0.28 |
|
|
McKinley's
3:00 - 3:30 PM |
132 |
23 |
0.11 |
|
|
McKinley's
9:00 - 9:30 PM |
163 |
28.4 |
0.14 |
|
Wednesday |
Schultz |
227 |
39.5 |
0.20 |
|
|
Brooks 1:30 –
2:00 PM |
177 |
30.8 |
0.15 |
|
|
Brooks 7:15 –
7:30 PM |
305 |
53.1 |
0.26 |
|
|
McKinley's
3:00 - 3:30 PM |
148 |
25.75 |
0.13 |
|
|
McKinley's
9:00 - 9:30 PM |
91 |
15.83 |
0.08 |
|
Thursday |
Schultz |
242 |
42 |
0.21 |
|
|
Brooks 1:30 –
2:00 PM |
215 |
37.4 |
0.19 |
|
|
Brooks 7:15 –
7:30 PM |
335 |
58.3 |
0.29 |
|
|
McKinley's
3:00 - 3:30 PM |
98 |
17 |
0.08 |
|
|
McKinley's
9:00 - 9:30 PM |
125 |
21.75 |
0.11 |
Friday |
Schultz |
368 |
64 |
0.32 |
|
|
Brooks 1:30 -
2:00 PM |
205 |
35.67 |
0.18 |
|
|
Brooks 7:15 -
7:30 PM |
198 |
34.45 |
0.17 |
|
|
McKinley's
3:00 - 3:30 PM |
155 |
27 |
0.13 |
|
|
McKinley's 9:00
- 9:30 PM |
70 |
12.18 |
0.06 |
|
Saturday |
Brooks 1:30 -
2:00 PM |
162 |
28.2 |
0.14 |
|
|
Brooks 7:15 -
7:30 PM |
235 |
40.9 |
0.20 |
|
|
McKinley's |
76 |
13.22 |
0.07 |
|
|
McKinley's
9:00 - 9:30 PM |
56 |
9.74 |
0.05 |
|
Sunday |
Brooks 7:15 -
7:30 PM |
431 |
75 |
0.37 |
|
|
McKinley's
3:00 - 3:30 PM |
64 |
11.1 |
0.05 |
|
|
McKinley's
9:00 - 9:30 PM |
47 |
8.2 |
0.04 |
|
TOTALS |
|
6,200 |
1,078.76 |
5.35 |
*Note: this is per week, not per day
Carnegie and Steffee
buildings: approx. .59 – 1.8 cu.
yds./week*
Compostable Waste Found in Rat Facilities of Carnegie
and Steffee
· Material used for bedding in rat cages is rough cut sawdust.
· Carnegie has far more rats than Steffee.
· There is an extremely high variability in the amount of bedding and waste that these facilities go through due to the fact that rats are killed off at different times of the year depending on classes.
· Rat population in Carnegie can vary as much as from 125 rats to 800 rats.
· During low population levels (estimated: 42 weeks) weekly sawdust and rat waste for both buildings will be between 260 and 390 pounds (.59 - .89 cu. yds./week).
· During high population levels (10 weeks) the average weekly weight of both buildings rat waste is 585 to 780 pounds (1.34 - 1.78. cu. yds./week).
The calculations and estimations
in this section were determined figuring that of the 30 weeks that school is in
session, 10 of those weeks have high populations of rats and the other 20 weeks
have low populations. We also assume
that there is a low population during the remaining 22 weeks of the year. The rat population of Carnegie can vary from
as low as 125 rats to as high as 800 rats.
At peak rat population which occurs roughly during the middle part of
the semesters, the Carnegie building uses between 7-9 cans of sawdust per week
(cans are 30 gallons and hold 65 lbs).
During this period the weight could be roughly between 455 and 585
pounds.
Beginning around the time comps are due, rats are usually killed off at high rates. This lowest population is during the summer at which time only 2-3 cans are required per week. During this time period the Carnegie colony uses approximately 130 to 195 pounds of sawdust. During August the populations are brought back up and peak population is reached around the beginning of September.
In Steffee where fewer rats are held, we were informed that between 2 or 3 cans per week are used to cover its rat population, making the weekly average roughly between 130 and 195 pounds (.30 to .45 cu. yds./week). The total average weekly weight of sawdust during peak times (10 weeks) for both buildings is approximately between roughly 676 and 897 pounds. At low population levels (42 weeks) such as during the summer, weekly sawdust weight for both buildings will be between 260 and 390 pounds (.49 to .89 cu. yds./week). The average weekly weight of both buildings throughout the year is 281.7 pounds.
|
Location |
Time of pick-up |
Number of totes |
Time required |
Pick-up days |