TO TRAY OR NOT TO TRAY?
The research below was conducted by Sasha Bereznak ’11 and Alyssa Martin ’10. Both students investigated the costs and benefits of eliminating trays in the dining halls of Bryn Mawr College. While the benefits to this decision are consistent with the college’s goal of reducing its carbon footprint by 10%, Sasha and Alyssa found that student sentiment may outweigh the potential savings that could be acquired.
Cost of Cleaning Trays
|
Period of Savings |
Calculation Details |
Savings per Period |
|
Day |
$0.06/tray * 2718 trays/day |
$163.06/day |
|
Week |
$163.06/day * 7 days/week |
$1,141.39/week |
|
Fall Semester |
$1141.39/week * 16 weeks/semester |
$18,262.27/semester |
|
Spring Semester |
$1141.39/week * 17 weeks/semester |
$19,403.66/semester |
|
Total Academic Year |
$18,262.27/semester + $19,403.66/semester |
$37,665.94/academic year |
Water Consumption
|
Period of Consumption |
Calculation Details |
Consumption per Period |
|
Day |
340 racks/day * .45 gal/rack |
153 gal/day |
|
Week |
153 gal/day * 7 days/week |
1070 gal/week |
|
Fall Semester |
1070 gal/week * 16 weeks/semester |
17,123 gal/semester |
|
Spring Semester |
1070 gal/week * 17 weeks/semester |
18,194 gal/semester |
|
Total Academic Year |
17,123 gal/semester + 18,194 gal/semester |
35,317 gal/academic year |
Food Waste with Trays
|
Food Waste With Trays (04/06/2010) |
63.5 lbs |
|
|
Number of In-Erdman Diners |
|
376 |
|
Waste Per Person |
(in lbs) |
0.169 |
|
|
(in ounces) |
2.702 |
Food Waste without Trays
|
Food Waste Without Trays (04/13/2010)
|
66.0 lbs
|
61.63 lbs (adjusted) |
|
|
Number of In-Erdman Diners
|
|
382
|
|
|
Waste Per Person
|
(in lbs)
|
0.173
|
0.16 (adjusted) |
|
|
(in ounces)
|
2.764
|
2.581 (adjusted) |
The Bigger Picture
|
Period of Consumption |
Calculation Details |
Consumption per Period (oz) |
Consumption per Period (lbs) |
|
Day |
2718 students * (2.702 oz -2.581 oz) |
328.878 oz/day |
20.555 lbs/day |
|
Week |
328.878 oz/day * 7 days/week |
2,302.146 oz/week |
143.884 lbs/week |
|
Fall Semester |
2,302.146 oz/week * 16 weeks/semester |
36,834.336 oz/semester |
2,302.146 lbs/semester |
|
Spring Semester |
2,302.146 oz/week * 17 weeks/semester |
39,136.482 oz/semester |
2,446.030 lbs/semester |
|
Total Academic Year |
36,834.336 oz/semester + 39,136.482 oz/semester |
75,970.818 oz/academic year |
4,748.176 lbs/academic year |
To see their complete work, click here.
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