Residence-to-Garden Greywater Delivery System
Student team: Reynold Ly, Patrick Stoner, Leon Huderson, and Janelle Dey
Faculty: Nisse Goldberg, Lee Ann J. Clements, and W. Brian Lane
Jacksonville University - 2010
The Grey Water Project
The Grey water Project participated in the EPA P3 competition, funded by the EPA for college
students to develop innovative ideas or solutions to address challenges for a sustainable future.
These solutions had to meet the three themes or “P3” which were “People, Prosperity, and
Planet.” The theme refers to developing sustainable solutions that benefit people, promote
prosperity, and protect the planet while addressing challenges to sustainability. This
competition consists of two phase: Phase I and Phase II. Phase I is when interdisciplinary
student teams compete for $10,000 grants. Teams that receive the grants use the funding to
research and develop their projects during the academic year. The teams in the spring submit
project reports and Phase II proposals to a panel of judges from the American Association for
the Advancement of Science. Teams then present their project in Washington D.C for judging at
the annual National Sustainable Design Expo on the National Mall. Based on reports, proposal,
and presentations, judges recommend to the EPA which teams should receive the EPA p3
award and Phase II funding.
The goal of this project is to design a low-cost grey water delivery system that can be used with
university residential buildings or similarly sized apartment complexes. A multi-stage collection
and delivery system was designed by students to irrigate a demonstration garden using first
rainwater and AC condensate. Students also developed a design for a separate collection and
delivery system using laundry wastewater.
This project was developed in mind to address issues related to Florida’s growing freshwater
shortage and pollution in the St. Johns River. Nutrient runoff is responsible for the high
concentration of phosphorus and nitrogen in the St. Johns River which results in the increase of
the frequency and intensity of algal blooms (Jacksonville University and University of North
Florida 2008). Collecting the runoff in grey water and reusing it for irrigation redirects the
nutrients to aid in plant growth instead. This reduces freshwater consumption for irrigation,
which leads to a reduction in water bills.
This project also addresses the growing problem of water conservation in areas facing increases
of drought. Water accessibility is affected by the increase in the frequency and length of
drought periods (Pandey et al. 2003). This forces water conservation to become priority one in
many communities because of climate change (Pandey et al. 2003). According to Pandey et al.
(2003), utilizing rain-harvesting technologies over time has been preferred to migration in
response. This project demonstrates water conservation efforts can be relatively straightforward and affordable.
Students during spring of 2009 (Frank Gonzalez, Julie Hammond, Ryan Keith. Sasha Merced, and
Audrey Miller) worked with Dr. Goldberg, Dr. Clements, and Dr. Lane on writing the project
proposal for Phase I funding. This proposal focused on the design and implementation of the
residence-to-garden-greywater delivery system for harvesting rainwater and air conditioning
condensate for irrigation of a demonstration garden. EPA approved the proposal, granting the
project team $10,000 for project design and development over the next academic year.
The team in the next following semester consisted of new students (Leon Huderson, Reynold
Ly, Patrick Stoner, Eric Carmody, Erdy Dieujuste, Jenna Manis, Elizabeth Janiak, Kenzie Forkal,
Janelle Dey, and Derrick Barra) who worked on project objectives of Phase I of the project
during the academic year. At the same time, a new proposal was being developed for Phase II
funding. This proposal focused on the implementation of a grey water irrigation system that
meets Florida state regulations regarding storage of laundry wastewater. During the spring of
2010, students (Leon Huderson, Reynold Ly, and Patrick Stoner) as well as investigators
Goldberg, Lane, and Clements went to Washington D.C. to present the project to judges at the
National Sustainability Design Expo. The team competed with other teams for Phase II funding.
Unfortunately, we weren’t able to obtain funding, and so the project ends with Phase I.
Findings and results of this project for Phase I include: A/C survey results, Campus attitude
results, and estimates to ascertain cistern size for irrigation of the garden with rainwater and
A/C condensate, and estimates for the frequency and amount of water used for irrigation of the
garden.
Campus attitudes results: 89% felt it was necessary to conserve water. 31% had previously
heard of the term “grey water”. When provided with definition of grey water, 79% felt that it is
acceptable to use grey water in the environment (ex. flower garden)
According to an A/C preferences survey, the average temperature in the student apartments is
70° Fahrenheit. About 43% of respondents from the survey answered they kept the air
conditioning temperature between 63°F and 70°F. It was also found air conditioning was kept
on about 19 hours a day (survey). Therefore, it was concluded a/c condensate was in ample
supply.
Air conditioning condensate was estimated based on a rule of thumb that 0.1 to 0.3 gallons of
air conditioning condensate is produced per ton of air conditioning that operates per hour
(Wilson 2008). For building six, there are eight 2.5 ton units and four 3 ton units that total up to
be 32 tons total. The total of tonnage is multiplied by 0.3 gallons/ton of A/C per hour to get
about 9.6 gallons per hour. For 1 day, it was calculated to be 230 gallons of air condensate
produced.
The cistern size needed to store A/C condensate and rainwater was determined to be 1,200
gallons based on A/C condensate calculations and rainfall estimates. It was estimated that 536
gallons of rain is collected per day based on average monthly rainfall in the Jacksonville area.
(Department of Meteorology, University of Utah). Average rainfall per year is 52.34 inches per
year. Based this amount, the average rainfall per month in feet was determined, then
multiplied with the area of the roof (6000 sq ft) to get the total cubic ft of rain per year (26,170
ft3 /year). The total feet of rain per year were converted to gallons by multiplying by 7.48
gallons per cubic feet to get 195,751.6 gallons per year. 536 gallons was calculated by dividing
the total amount of rainfall in gallons per year by 365 days.
For garden irrigation, it was estimated the garden will require approximately about 65 gallons
per watering event. The garden is watered every two days during the spring and summer
months and every 10 days during the fall and winter months (Florida Green Industries 2002).
Phase II
Phase II was developing and implementing a separate design for the collection and delivery of
laundry wastewater to the garden for irrigation. A filtration tank and another cistern are
required to properly store laundry water. In the case of overflow, laundry water can be diverted
to sewer lines.
The size of the cistern is estimated to be 2500 to 3000 gallons based on an estimated amount of
1,728 gallons laundry wastewater produced per day per residential building. A typical US toploading washing machine uses 30 gallons per cycle (greywater.com). This estimation was
calculated based on 192 students using the laundry room per week, the total number of
students living in the four apartment buildings with laundry rooms. The average number of
washes expected per day was calculated to be 27.4, multiplied with 63 gallons (2-cycle laundry
wash) to get 1,728 gallons per day.
It was planned to alternate between the rainwater and AC condensate stored in the cistern
from Phase I with the grey water (laundry wastewater) stored in the cistern proposed for Phase
II for irrigation of the garden. We wanted to switch the sources of water to minimize potential
negative impacts of grey water to the soil such as changes in nutrient concentration or changes
in pH (Pinto et al. In press). Zinc toxicity can occur in plants with a soil pH of 8.5 or greater
(Christova-Boal et al. 1996). Salts contained in laundry detergents can also be detrimental (49480 mg/L) because they can contribute to the salinization of the soil (Christova-Boal et al.
1996).
References
Christova-Boal, D., Eden, R.E., McFarlane, S. 1996. An investigation into greywater
reuse for urban residential properties. Desalination 106: 391-397.
Department of Meteorology, University of
Utah.<http://www.met.utah.edu/jhorel/html/wx/climate/normrain.html>. Accessed
December 6, 2008.
Florida Green Industries. 2002. <http://hort.ufl.edu/bmp/turfbmp.pdf>. Accessed
February 28, 2010.
Wilson, Alex and Navaro, Rachel. Alternative water sources: supply-side solutions for
green buildings. <www.buildinggreen.com/auth/article.cfm/id/3903>.
Pandey, D. N., Gupta, A. K., and Anderson, D. M. 2003. Rainwater harvesting as an
adaptation to climate change. Current Science 85: 46-59.
Pinto, U., Maheshwari, B.L., and Grewal, H.S. (In press). Effects of greywater irrigation
on plant growth , water use and soil properties. Resources, Conservation and
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State of the River Report for the Lower St. Johns River Basin, Florida: water quality,
fisheries, aquatic life, and contaminants. 2008. A report prepared for the Environmental
Protection Board of the City of Jacksonville, Jacksonville, Fl. by Jacksonville University
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