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Water Conservation

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.