A highly productive aquifer beneath Purdue University provides the campus with a low-cost, high quality supply of potable water, which is pumped by on site wells for use in buildings, irrigation, and as make-up water for the district energy system. As the owner of this resource, Purdue pays a relatively small price per unit compared to many universities that procure water from a public agency. Consequently, the bulk of costs associated with water consumption are not related to purchasing but to wastewater disposal.
To provide the West Lafayette Wastewater Treatment Utility with an accurate sanitary sewer bill, all campus buildings are outfitted with water meters. Deduct meters are installed to measure water quantities that are not discharged into the sewer system, such as irrigation water. Knowing where and how much water is being used allows the campus to implement targeted water saving projects and monitor the results. A web-based meter reading system being developed will soon provide the campus community with access to water usage data.
Several retrofit projects are being implemented to produce immediate water savings. University Residences is replacing existing 2.5 gallon per minute (GPM) showerheads with 1.75 GPM models, and installing 0.5 GPM faucet aerators on existing 2.2 GPM faucets. In 2009, the flush valves for water closets and urinals in twenty buildings were retrofitted with flow restrictors. Based on initial testing, these devices are expected to produce domestic water savings of 15 to 20 percent. The university’s retro-commissioning effort has identified several opportunities to curb process water usage, including converting once-through cooling systems to the campus chilled water system, which will be applied campus-wide.
Purdue is helping to protect its underground water resources with a comprehensive storm water management program. Storm water treatment best management practices demonstrated on campus include infiltration beds, bioswales, porous paving, and a green roof at Schleman Hall. The university recently completed a storm water master plan that will help it exceed regulatory requirements and improve water quality through innovative strategies like green roofs and capture/reuse systems.
A comprehensive wellhead protection program further reduces pollutant infiltration into the aquifer. Under this program the campus identifies and closely manages contaminant sources on land near its wells to safeguard its drinking water supply and protect the local environment. The university’s water management practices are also strong in Campus bioswale the area of site water conservation. The campus irrigation system, comprised of sixty distinct smaller systems and over five hundred valves, is being upgraded with weather-sensing technology. The new sprinkler controls use real-time weather data to adjust irrigation quantities automatically in response to changing weather conditions. Other site factors are monitored as well, including soil moisture, wind conditions, slope, and soil and plant type, to optimize the application of irrigation water and maintain plant health while conserving water resources.
Purdue will track the following metrics to assess its water use performance overtime.
Site water: 2014 Short Term Goals
- Maximize opportunities to reduce water usage for irrigation.
Site water: 2025 Long Term Goals
- Establish an organic turf management plan during the site-planning phase for all new construction projects and then determine appropriate design and water savings goals for the irrigation system to ensure both aspects of the site are developed concurrently.
- Target athletic fields adjacent to wells for irrigation with well-house startup water, and time irrigation activities for off-peak athletic field use.
- Capture and redirect water flushed from wells on startup, which is normally directed into the storm sewer systems, into other non-potable uses such as chillers or infiltration.
- Win the Hoosier Water Guardian award for campus potable water supply.
Building water: 2014 Short Term Goals
- Adopt maximum flush and flow requirements for all water-using fixtures.
- Continue to pilot and test water saving fixtures and devices.
- Develop and implement a cooling tower water management plan that results in optimal water efficiency and chemical usage.
Infrastructure water: 2014 Short Term Goals
- Continue to explore opportunities to redirect water from the sanitary system.
Infrastructure water: 2025 Long Term Goals
- Assess opportunities to reuse stormwater in the chiller plant cooling towers to offset potable water use.
- Expand the chilled water loop system where feasible to eliminate the need for potable once through cooling water.
Resource conservation and protection: 2014 Short Term Goals
- Promote water conservation during Green Week.
- Include an educational/behavioral change component to building water metering efforts by publicizing water usage data via the sustainability website.
- Capitalize on synergies with the Wellhead Protection Program by coordinating projects so that groundwater resource protection and stormwater management concerns are mutually addressed.
Resource conservation and protection: 2025 long Term Goals
- Work with students to perform water audits on a representative set of campus buildings to develop baselines for gauging water efficiency improvements over time.