Letter of Intent Project Title: Putting the Green in Greenhouse, revised March, 2016
Estimated additional amount requested from CSF: $34,635
Summary of project proposal:
Original proposal summary:
The UW Botany Greenhouse was approved to construct an improvised rainwater collection system to route greenhouse roof rainwater to makeshift holding tanks under greenhouse benches. The collected water would then be utilized to water greenhouse plantings and decrease the Seattle City water needed to accomplish daily watering of plantings within the greenhouse. Shortly after funding was allocated the UW decided to move forward with construction of a new Life Sciences Building (LSB) on the site of the existing greenhouse and Plant Lab. Construction of the rainwater collection project was halted with no funds expended pending design considerations by the LSB building project.
Revised proposal incorporating rainwater collection into the design of the new LSB:
LSB design team contributed many hours of engineering and project time to careful consideration of various options for effectively including rainwater collection in LSB. Many technical difficulties were discussed and reviewed in light of previous UW experience with such systems. Most recently, a professional design was proposed that was very similar to original improvised design (figure 1, Option 2*). However, filtration difficulties and unreliable supply of rainwater during peak greenhouse watering summer months continued to give pause to decision makers. In addition, installation costs were quite high. As a result the design team was directed to look again for better options that could resolve the filtration and supply problems.
Improved design for greenhouse by redirecting RO/DI system reject water:
Capturing reject water from the LSB reverse osmosis/de-ionization system (RO/DI) would provide a year round reliable water source and solve problems of rainwater seasonal supply and roof water collection filtration. Contemporary science buildings routinely include RO/DI systems to “clean” tap water into pure water needed for today’s research. Although RO/DI systems are much more water efficient than historical water purification systems using boilers and water cooled condensers, RO/DI systems still waste 2 gallons per minute (gpm) in operation that goes directly to the sewer. The current design (figure 2) will utilize the RO/DI waste water to provide a year round, reliable and clean supply to the greenhouse fertilized water system to mitigate use of Seattle City water. In addition to reuse of waste water for irrigation, the uptake of irrigation water by the plants will decrease the water eventually going to the sewer by 50-75%. Simplification of the piping design and utilization of a smaller tank, given the reliable water supply, markedly decreased the cost of installation.
Environmental impact: 24 UW science buildings have RO/DI systems of which only one has marginal provision to redirect system waste water for other purposes in lieu of passing to sewer. LSB reuse of RO/DI will provide a new standard for current and future sciences building to design similar redirection of RO/DI waste water for conventional and more imaginative purposes, i.e., LSB will redirect to greenhouse irrigation which is a unique component of building design at UW. During operation of building RO/DI systems, 2gpm passes to the sewer system. In other words, calculated supply that would otherwise pass to the sewer is 800gpd, 24,000 gallons per month (gpm), 288,000 gallons per year (gpy). Intent of this project is to utilize the reject water for irrigation in the greenhouse. Comparison of reject and tap water samples verify the reject water is safe and acceptable for irrigation of plants.
Student Leadership and Involvement: The Life Science Building project now includes volunteer student participation through all remaining phases of design, construction, and commissioning to full operation. Essentially, student participants will have an on campus internship with an established engineering firm on an actual major project at a major university – significant on-the-job experience for anyone interested in engineering or installation of sustainability projects. Frankly, it’s very encouraging to hear the enthusiasm of the design team architects and engineers welcoming student participation for Putting the Green in Greenhouse.
Education, Outreach, and Behavior Change:
- Education & outreach: see student involvement above; LSB project plans to include information on the main lobby media wall to educate visitors of sustainability measures included in the Life Sciences Building and highlight student involvement. Signage in the new greenhouse will describe the re-use of RO/DI reject water for plant care, and this sustainability effort will be highlighted in guided tours taken by thousands of people who visit the greenhouse each year. Many of the greenhouse visitors are K-12 students and their teachers as well as many undergraduates across the UW community who tour the greenhouse as part of their coursework.
- Behavior change: use of RO/DI system reject water would be a new approach for UW building construction which would encourage similar designs in any new construction that included a RO/DI building system. 24 buildings on the Seattle campus have RO/DI systems now.
Feasibility, Accountability, and Sustainability: Much consideration has been given to approaches to lessen the impact of greenhouse water use for irrigation. A talented design team of architects, engineers, and building construction professionals have diligently investigated the best approach to move toward better water sustainability in the Life Sciences Building while remaining within project budget constraints. The current design provides the most responsible means for sustained mitigation of greenhouse water use for irrigation.
$35,000 Mechanical materials and equipment cost
$28,000 Mechanical labor cost
$7,000 Mechanical permits, drawings, management cost
$4,000 Electrical materials and equipment cost
$2,500 electrical labor cost
$1000 Electrical permit, drawings, management cost
$8,500 Management cost
Total above = $86,000 Total construction cost (sum of above line items)
Plus $26,000 Project cost
Total 2 lines above = $112,000 Total cost to include in LSB design for construction (sum of two items above); in service July 2018
minus $77,365 amount of CSF grant for original concept
$34,635 requested additional funds to complete “Putting the Green in Greenhouse”
Summary of key points:
1. Water supply revised to building RO/DI system reject water instead of roof rainwater:
- Advantage of consistent, year round supply, especially in dry, warm weather months.
- Advantage of clean source of water eliminating excessive filtration maintenance and ongoing costs for fliter replacements
2. Student involvement provides excellent resume and networking opportunity.
3. Project to be highlighted in guided tours taken by thousands of people who visit the greenhouse each year. Many of the visitors are K-12 students and their teachers as well as many undergraduates across the UW community who tour the greenhouse for their coursework.
4. Construction costs are remarkably similar to original concept givne more workable design and construction
*costs shown on figure 1 are cost of construction only; compare to $86,000 for improved design using RO/DI reject water here