The Scottsdale Water Campus is home to the Advanced Water Treatment Plant, one of the most sophisticated recycled water facilities in the world and the first permanent facility in Arizona – and only the third in the nation – to be permitted for direct potable reuse.
The AWT is one of the largest potable water reuse facilities in the world and can treat up to 20 million gallons of water a day to a water quality standard that exceeds that of bottled water.
The Advanced Water Treatment Plant at the Scottsdale Water Campus has been performing indirect potable reuse – recharging highly-purified water into the drinking water aquifer – for over 20 years. The facility takes tertiary effluent from the city’s conventional water reclamation plant and further treats it through ozonation, membrane ultrafiltration, reverse osmosis and ultraviolet photolysis. (Click each process for a process animation.)
That finished water, often referred to as RO permeate, is then injected into a series of dry wells where it flows through an additional 400 feet of natural filtration, known as the vadose zone, before reaching our drinking water aquifer, or sent to the Reclaimed Water Distribution System.
Scottsdale recharges over 1.7 billion gallons of purified recycled water to replenish our drinking water annually. Due primarily to the AWT, Scottsdale has recharged over 70 billion gallons into regional aquifers since 1988.
While the water produced by the AWT is considered ultrapure, up until 2018, there was a statutory preclusion in Arizona against using recycled water for direct potable use. Recognizing that approved removing the prohibition, which allowed the Arizona Department of Environmental Quality to permit water systems for direct potable reuse. Recognizing the advances in technology and monitoring capabilities, the state removed the direct human consumption prohibition opening the door for cities across Arizona to begin the process of moving toward direct potable reuse as a viable long-term water supply.
In September 2019, after 18 months of working closely to create criteria for monitoring and regulation of purified reclaimed water, Scottsdale Water was issued the state's first permit for direct potable reuse.
Scottsdale is not sending the highly-purified recycled water into the drinking water system at this time. Instead, Scottsdale will continue to meet customer needs through its diverse water supply portfolio, which includes using indirect potable reuse to recharge the aquifer for future beneficial use. Other cities, however, are actively pursuing direct potable reuse as a long-term water source and Scottsdale’s executed permit provides a blueprint to guide them down that path.
Reclaimed Water Distribution System
Since the early 1990s, the city of Scottsdale has been providing non-potable water to 23 golf courses in north Scottsdale through a public-private partnership known as the Reclaimed Water Distribution System (RWDS). The RWDS is a complex system of pipelines, booster pump stations and reclaimed and advanced water treatment facilities capable of delivering 20 million gallons a day of non-potable water for turf irrigation specifically to RWDS member clubs.
The RWDS was first conceived and negotiated by Desert Mountain Properties and the city of Scottsdale as a means of terminating north Scottsdale golf courses’ reliance on precious groundwater resources for irrigation. Through the agreement, Desert Mountain and 12 other golf clubs have invested $30 million to build and fund capital improvements to the system and are contributing a subsequent $22.5 million toward the expansion of the Advanced Water Treatment Facility to improve the quality of water being delivered.
Today, the city of Scottsdale owns and operates the RWDS with member clubs paying for both their respective water purchases and 100 percent of the system’s collective maintenance, operation and capital costs.
In the non-peak months when the courses do not need their daily water allotments, the city uses the excess purified water from the Advanced Water Treatment Facility for aquifer recharge through indirect potable reuse, further advancing Scottsdale’s long-term water sustainability.