phung 1 thuy - williams college
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Thuy Phung GEOS 206 Professor David Dethier, Stephanie Boyd and Amy Johns Final Project 5/18/2010
Planning for Water Use in the new Sawyer Library
Install Dual‐flush Toilets to Save Water
Introduction
Fresh water is a valuable and finite resource, yet too often taken for granted when we
have it in abundance. Having clean piped water in the house for all purposes from drinking to
flushing the toilets often makes us forget the fact that as of 2009, more than 884 million people
in the world still lack access to clean water and 2.5 billion remain without improved sanitation
(UNICEF, “Water, Sanitation and Hygiene,” 2010). Furthermore, the world’s fresh water
resources are dwindling due to a combination of population growth, overconsumption,
contamination, and climate change. As for the United States, the EPA reports that “at least 36
states are anticipating local, regional, or statewide water shortages by 2013, even under non‐
drought conditions” (EPA WaterSense, “Water Supply and Use in the United States,” 2008). This
is not to mention the negative impacts of human water use on different species and the
ecosystem. Therefore, better water management with an emphasis on conservation is strongly
needed if we want to solve this current and future water crisis.
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Surprisingly, the largest user of water in homes in the United States is the flush toilet,
which accounts for nearly 30 percent of household indoor total water use (EPA WaterSense,
“Toilet,” 2010). The toilet not only requires but also contaminates large volumes of potable
water. The amount of water required by toilets in the United States has decreased by up to 75%
due to the National Energy Policy Act of 1992 which mandated that new toilets use no more
than 1.6 gallons per flush (Gleick, 2003). However, greater reductions can be made, and one
easy and efficient way is to install dual‐flush toilets. Dual‐flush toilets are widely use in Australia,
Europe, and Asia. In fact, water‐stressed Australia has mandated the use of dual‐flush toilets
nationwide. Several municipalities and states in the United States with a high risk of drought
have also adopted similar measures, such as California which recently passed a bill that requires
new toilets to meet the high‐efficiency standards of 1.28 gallons per flush (gpf) (Ramde, 2007).
Nevertheless, dual‐flush toilets are still a relatively new technology and are just catching on in
most of the United States.
In this project, I examine the feasibility of installing dual‐flush toilets at Williams College.
Williamstown does not face water shortage due to the large annual quantities of snow and rain;
however, for environmental and educational purposes Williams College should try its best to
conserve water. Most of the toilets and urinals on campus meet the Energy Policy Act of 1992
requirements (1.6 gpf for toilets and 1.0 gpf for urinals) (Jensen, Ken). However, there are 128
toilets that exceed this standard (Diuguid, Danielle). There is currently only one dual‐flush toilet
on campus in Kellogg House which was home to the Center of Environmental Studies, but the
building was closed in 2008 since it stood in the way of the Stetson‐Sawyer library project (Boyd,
Stephanie). As installing new toilets is easier than replacing existing ones, I decide to look at the
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new Sawyer Library (Figure 1 and 2). The building was scheduled to be completed by 2011, but
has been put on hold since 2008 due to the financial crisis. The purpose of my study is to find
out how much water will be saved in the new library by installing dual‐flush toilets instead of
low‐flow toilets as currently planned. From there, I will discuss the benefits, costs, and
challenges of installing dual‐flush toilets campus‐wide.
Figure 1: View from Paresky Center when the old Sawyer Library has been razed and the new library is completed. Source: http://library.williams.edu/news/290
Figure 2: Watercolor rendering of Stetson‐Sawyer Project when completed, by Sarah McNair. Source: http://www.williams.edu/go/stetsonsawyer/finalview.htm
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Settings
The new Sawyer Library will be
attached to a renovated Stetson Hall. The
Sawyer building is going to be a library/ IT
complex. Apart from replacing the
current Sawyer Library, it will also house
the College Archives, the Chapin Library,
and the OIT Center for Media Initiatives
(Pilachowski, David). As an academic
building, the water usage of the new
library is lower than that of residential
dormitories, making it easier to install
low‐flow fixtures.
Method
To predict the water use in the new Sawyer Library, I first study the North and South
Academic Buildings since these three buildings all belong to the Stetson‐Sawyer Project. The
North and South Academic Buildings are office/ classroom buildings; they were completed in
August 2008 and were recently named Hollander Hall and Schapiro Hall respectively. Designed
by the same architects Bohlin Cywinski Jackson, Hollander Hall, Schapiro Hall, and the new
Library share many common features. They all seek LEED certification from the US Green
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Building Council, and Hollander Hall and Schapiro Hall were recently awarded LEED Gold Status.
One of the criteria for LEED certification is water efficiency, and LEED has a specific template to
calculate water savings by installation of low‐consumption fixtures. To measure the accuracy of
this calculation method, I first compare the estimate and actual water usage of Hollander Hall
and Schapiro Hall to see how well they match up. After that I use the LEED template to calculate
water savings in the new Sawyer Library when going from low‐flow toilets to dual‐flush toilets.
The most important thing to note is that the LEED methodology is based on estimated occupant
usage and fixture flow rates instead of fixture counts as in traditional calculations. Estimated
occupant usage is calculated by multiplying Full‐Time Equivalent and transient occupants with
the appropriate fixture use rates (LEED for New Construction Version 2.2). In other words,
what matters is the efficiency and usage frequency of the fixtures, not how many fixtures there
are in the buildings.
Results
The complete LEED water efficiency form for Hollander Hall and Schapiro Hall is included
in Appendix 1. The installation of low‐flow water closets, non‐water urinals, and ultra low‐flow
lavatories in these two buildings results in a 40% water saving compared to the baseline case of
conventional fixtures. The estimated annual water consumption of the two buildings is 237,817
gallons/ year, which is close to the actual usage of 286,484 gallons for fiscal year 2009 (July
2008‐June 2009) (Boyd, Stephanie). This gives me reasons to believe that my estimates of water
use in the new Sawyer library using the same techniques will be quite accurate as well.
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The first step is to figure out the occupancy breakdown of the new Library, and the
result is shown in Table 1. According to David Pilachowski and Bruce Decoteau, there will be 17
faculty, 38 staff in the library and 12 in OIT, which make up a total of 67 Full Time Equivalent
occupants. As for the transient occupants, the new security gate system that tracks people
coming and going from the current Sawyer library suggests that there are on average 1,200 ‐
1,500 students, faculty, staff and other visitors each day. Using this data, David Pilachowski
estimates that the daily use of the new Sawyer for library and IT use will be approximately
2,000. I estimate annual days of operation to be 220, same as the number used for Hollander
Hall and Schapiro Hall. The Library is open nearly all year round; however this number is to
adjust for the summer and other periods with low numbers of users.
Table 1 ‐ Occupancy Breakdown (Default Male/ Female Occupancy)
Full Time Equivalent Student/VisitorTotal 67 2000Male 33 1000Female 34 1000
Percent of male restrooms with urinals: 100%Annual Days of Operation (1‐365): 220
The second step is to calculate the baseline case. Bruce Decoteau confirms that the
fixtures used in the new Library are of the same types as those currently installed in the two
Academic Buildings; therefore I use them as my baseline case. The result is reported in Table 2
and 3:
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Table 2 ‐ Flush Fixture Data ‐ Baseline Case
Baseline Fixture Type Gender Flush Rate (GPF) % of Occupants Daily Uses Per PersonFTE Student/Visitor
1 Low‐Flow Water Closet Female 1.5 100% 3 0.52 Low‐Flow Water Closet Male 1.5 100% 1 0.13 Non‐Water Urinal Male 0 100% 2 0.4
Annual Baseline Flush Fixture Water Usage 242,550
Table 3 ‐ Flow Fixture Data ‐ Baseline Case
Baseline Fixture TypeFlow Rate (GPM) Duration (seconds) Daily Uses Per Person
FTE Student/VisitorA Ultra Low‐Flow Lavatory 0.5 15 3 0.5BC Kitchen Sink 2.5 15 1D Janitor Sink 2.5 15 0.1
Annual Baseline Flow Fixture Water Usage 43,161.25TOTAL ANNUAL BASELINE WATER USAGE 285,711.25
Next, I calculate the design case (Table 4). The only change from the baseline case is that
low‐flow toilets (1.5 gpf) in female restrooms are replaced with dual‐flush toilets (1.6 gpf full
flush and 1.1 gpf low flush or 1.6*67%+1.1*33%=1.265 gpf on average). I chose Sloan Uppercut
WES‐111 as this is the model that many universities such as Harvard and Tuft are using.
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Table 4 ‐ Flush Fixture Data ‐ Design Case
Design Case Fixture Type Gender
Fixture Manufacturer
Fixture Model
Flush Rate (GPF)
% Occup‐ants Daily Uses Per Person
FTE Student/Visitor
1Dual‐Flush Water Closet, Full Flow Female Sloan
Uppercut WES‐111 1.6 0.33 3 0.5
2Dual‐Flush Water Closet, Low Flow Female Sloan
Uppercut WES‐111 1.1 0.67 3 0.5
3 Non‐Water Urinal Male KohlerSteward K‐4918 0 1 2 0.4
4Low‐Flow Water Closet Male Kohler
Kingston K‐4330 1.5 1 1 0.1
Annual Design Case Flush Fixture Water Usage 211,426.60TOTAL ANNUAL DESIGN CASE WATER USAGE 254,587.85
Finally, the design case total water usage is subtracted from the baseline case, which
shows that simply switching from low‐flow toilets to dual‐flush toilets saves 10.89% of water
per year (Table 5). This is consistent with the fact that toilet flushing is the largest water use in
the Library (accounting for 84.89% of total water use in the baseline case and 83.04% in the
design case).
Table 5 ‐ Water Use SummaryBaseline Case ‐ Annual Water Consumption: 285,711.25 gallons/ yearDesign Case ‐ Annual Water Consumtion: 254,587.85 gallons/ year
Total Water Savings: 31,123.40 gallons/ yearOR 10.8933057 %
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Discussion
The results show how installing dual‐flush toilets can greatly save water. There are some
uncertainties in the number of transient occupants and the annual days of operation in my
estimates; however, changing these two variables should not affect the percentage of water
saved very much, since the design case and the baseline case water use will just change
proportionally and in the same direction. Furthermore, there is not much difference in prices:
the Sloan dual‐flush toilet costs about $200 (Table 6), while the conventional and low‐flow
toilets cost around $250 (Jensen, Ken). Such a switch is not likely to face resistance from faculty
or students, either; therefore installing dual‐flush toilets in the new Sawyer Library is a viable
option. An important note is that new stickers and signs like in Figure 4 need to be installed to
remind users to flush up, as many are not used to the dual flush option.
Installing dual‐flush toilets in residential dormitories will lead to even greater savings of
water, since the daily use rate is much higher for residential occupants than for Full Time
Equivalent (5 versus 3). Going from 1.6 gpf conventional water closets to 1.265 gpf dual‐flush
closets means a reduction of 20% in the water used for flushing toilets. Dual flush toilets are as
good as conventional toilets, thus unlike low‐flow faucets or shower heads, they do not face
opposition from faculty or students and therefore are an easy way to save water. More
importantly, there is no need to replace existing toilets with brand new ones which cost $200
each. Most of the toilets on campus are 1.6 gpf flushometers and can easily be retrofitted into
dual‐flush toilets by simply changing the handle (Figure 4 and 5). The dual flush toilet handle
saves half a gallon of water per flush when the user flushes up (1.1 gallons instead of 1.6
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gallons). The price of the Sloan Handle Retrofit Kit is only $59 (Table 6), thus if the water rate
remains unchanged, an investment in retrofit kits will pay back in a short amount of time.
Figure 4: Sloan Dual‐Flush Water Closet WES‐111 Figure 5: Sloan Handle Retrofit Kit WES‐212A Source: http://www.sloanvalve.com/Our_Products/Manual_Flushometers.aspx Table 6: Cost of Sloan UPPERCUT Dual‐Flush Water Closet and Handle Retrofit Kit Source: http://www.sloanvalve.com/Prices/wlp_2009.pdf
For example, during the past year Harvard has added Sloan dual flush handles to 675
toilets in Faculty of Arts and Science bathrooms campus‐wide (“Water Conservation at FAS“).
When they installed low‐flow urinals and “dual‐flush” toilets in FAS libraries in 2009, the savings
from utility costs quickly added up (“HCL Plumbing Projects Conserve Water”). Dual‐flush toilets
have also been installed in residential halls in Tufts University, Columbia University, Northern
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Michigan University, and University of Denver etc to name a few (AASHE, “Dual Flush Toilets in
Residence Halls”).
However, a great challenge for Williams College is that Williamstown has a certain
infrastructure cost to deliver water and treat wastewater, thus a reduction in water
consumption causes the town’s water rates to go up. My email interview with Ken Jensen
reveals that in fact, it costs much more to get rid of the water than to buy water (currently
$4.92 versus $3.57 per ccf or 100 cubic feet), and the infrastructures are not just a one‐time
fixed investment – the costs to run the sewage treatment plant always increased or stayed the
same. One would think that if less water is consumed, less needs to be treated and the costs
should decrease. However, despite water conservation efforts, the Hoosac Water Quality
District (HWQD) sewage treatment plant is still sometimes overloaded (Jensen, Ken). This is
because many of the sewer lines in Williamstown are very old, and ground water and stream
water flood into them. As it is too expensive to dig up the ground and change the sewer lines,
the HWQD plant would rather treat the extra water (Professor Mea Cook, ENVI 102 class, Spring
2010). Williams College accounts for 30% of the Town’s total water use (Streicker, 2008). As a
result, in the year the College made large scale conversions of toilets, showers, faucets and
some water cooled devices, the water rate jumped by 30%, making the town residents quite
unhappy. Therefore, efforts to conserve water such as to install dual‐flush toilets need to be
carried out slowly to lessen the negative impact on the town residents. It seems not much can
be done about the town water rate, except for “the town people (probably) asking for a higher
accountability in where the money actually goes” (Jensen, Ken).
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While installing dual‐flush toilets brings little monetary gain, the environmental and
educational impacts are positive and important. By conserving freshwater – a valuable resource,
the College demonstrates environmental stewardship as well as global and local responsibility.
Williamstown gets water from a deep confined aquifer, which has a bed of clay on top which
prevents polluting sources from getting into the water and is thus much less susceptible to
contamination than an unconfined aquifer (Figure 1). This structure is not found everywhere,
and although the recharge rate seems to be adequate, the exact rate is unknown (Professor
Mea Cook, ENVI 102 lecture). Therefore, Williams College needs to manage this valuable
resource wisely.
Figure 6: Williamstown water aquifer Source: Professor Mea Cook, ENVI 102 lecture, Spring 2010
More importantly, installing dual‐flush toilets can lead to long‐term behavioral changes
in students. Seeing dual‐flush toilets as the norm on campus, students will make similar choices
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in their own homes, communities and future workplaces, especially when it is as easy as
changing the handle and the monetary incentive is likely to be much higher in these cases.
A further step is to use grey water such as rainwater, storm‐water, or wastewater from
bathroom showers, sinks, kitchen, and laundry rooms for toilet flushing. However, such a
system of collection, storage, and reuse is very complex, and there are health concerns and
regulations. The technology has not been well‐demonstrated, and is likely to face resistance
from faculty, staff, students, and students’ parents. Neither is such a project economically
sound – the system costs a lot while there is no saving from utility bills. Therefore, this option is
ruled out as a possibility for now, but it can be revisited in the future when the technology
becomes more developed, reliable and widely accepted.
Conclusion and Recommendations
Dual‐flush toilets are an easy and effective way to save water. After considering the
benefits and costs, I recommend that dual‐flush toilets should be installed in new and
renovated buildings, such as in the Stetson‐Sawyer project. In addition, the 128 toilets which
exceed the federal standard of 1.6 gpf should be replaced with dual‐flush toilets, especially in
light of the fact that they need to be converted anyway. Retrofitting the 1.6 gpf toilets, which
are the majority on campus, is more difficult but not impossible. I suggest a pilot project in
Williams and Sage Halls as it is easiest to change the habits of freshmen. After that the project
can expand to the rest of campus, but it needs to be carried out slowly to lessen the negative
impact on the Town.
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References
AASHE, “Dual Flush Toilets in Residence Halls”. Content Last Updated: 2/11/2009. Visited 5/18/2010. http://www.aashe.org/forums/dual‐flush‐toilets‐residence‐halls
EPA WaterSense, “Water Supply and Use in the United States”. Content Last Updated: 6/2008. Visited 5/18/2010. http://www.epa.gov/watersense/pubs/supply.html
EPA WaterSense, “Toilets”. Content Last Updated: 5/12/2010. Visited 5/18/2010. http://www.epa.gov/watersense/products/toilets.html
Gleick, Peter H., “Global Freshwater Resources: Soft‐Path Solutions for the 21st Century,” Science, New Series, Vol. 302, No. 5650 (Nov. 28, 2003), pp. 1524‐1528. Published by: American Association for the Advancement of Science. http://www.jstor.org/stable/pdfplus/3835774.pdf
Harvard University, “HCL Plumbing Projects Conserve Water”. Content Last Updated: 11/13/2009. Visited 5/18/2010. http://www.green.harvard.edu/node/523
Harvard University, “Water Conservation at FAS”. Content Last Updated: 2/17/2010. Visited 5/18/2010. http://green.harvard.edu/node/662
LEED for New Construction Version 2.2, Water efficiency.
Ramde, Dinesh, “New toilets meeting conservation needs,” Associated Press, December 9, 2007. http://www.postandcourier.com/news/2007/dec/09/new_toilets_meeting_conservation_needs24348
e, “Clean Water: The Ultimate Resource. Low‐Flow Fixtures in Williams Hall”. GEOS 206 5/10/2008.
d Hygiene”. Content Last Updated: 8/18/2009. Visited 5/18/2010. http://www.unicef.org/wash
Streicker, Ev
UNICEF, “Water, Sanitation an
te”. Content Last Updated: 2/1/2010. Visited 5/18/2010. http://library.williams.edu/newlibraryWilliams College, “New Sawyer Library ‐ Construction Upda
oject”. Content Last Updated: 2/2010. Visited 5/18/2010. http://www.williams.edu/go/stetsonsawyerWilliams College, “Stetson‐Sawyer Building Pr
Acknowledgements
ce k, and Danielle Diuguid for providing me with suggestions and
information for this project.
Many thanks to Stephanie Boyd, Professor David Dethier, Ken Jensen, David Pilachowski, BruDecoteau, Professor Mea Coo
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Appendix 1: LEED water efficiency form for Hollander Hall and Schapiro Hall
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