At a Glance
By harvesting and recycling water in this arid region, the Tempe Transit Center serves as a model for urban water reuse.
Tempe, Arizona’s new LEED-Platinum (pending certification) Transit Center building makes the most of the city’s annual rainfall of only 7.63 inches by reusing stormwater and greywater.
Biohabitats designed a treatment system to produce reclaimed, non-potable water by processing greywater, cooling tower blowdown, and stormwater runoff. Every day, 400 gallons of greywater from the building’s sinks and 1,000 gallons of water from its cooling tower are treated in a recirculating sand filter, disinfected, and reused to flush the building’s toilets. Stormwater from roofs and parking surfaces is captured, filtered for sediment and oil reduction, stored in a 12,000 gallon underground cistern and then used to supply the site irrigation system. These two systems provide a constant supply of high-quality reuse water; any unused reclaimed water passively overflows to the sanitary sewer.
Potable water is used as a back-up supply only when reclaimed water is not available. Both systems emphasize simplicity, ease of maintenance, a tight footprint, and energy efficiency as crucial design criteria for development of this urban water reuse model.