This Arizona Utility Makes Sustainability a Way of Life

Extensive water recycling, a diverse energy supply with renewables and clear communication of a sustainability vision set Scottsdale Water apart.

This Arizona Utility Makes Sustainability a Way of Life

Scottsdale’s 20 mgd advanced water treatment includes this reverse osmosis system.

The portfolio of sustainable practices at Scottsdale (Arizona) Water is wide and deep.

The utility received a 2018 Sustainable Water Utility Management Award from the Association of Metropolitan Water Agencies and a 2017 Public Education Program of the Year award from the WaterReuse Association for its Citizen Water Academy.

Scottsdale Water, serving a suburb of Phoenix, was also an inaugural winner of the Utility of the Future Today Award in 2016 from a consortium of water agencies. The utility has diversified its water and power sources and is an innovator in community partnerships to use reclaimed water for irrigation. It has practiced indirect potable reuse for 20 years and is helping to develop direct potable reuse.

“We are not an organization that rests on its laurels,” says Brian Biesemeyer, P.E., executive director. “We continue to improve. We pride ourselves on our vision: water sustainability through stewardship, innovation and people.”  

Making the vision real

That vision statement, adopted in 2013, is constantly communicated to customers and employees. It is printed on customer notifications, business cards, presentations, letterheads, display boards and handouts. It is even painted on the side of all of the utility’s vehicles.

Last year the utility marked the 20th anniversary of the Scottsdale Water Campus, a 145-acre facility that includes a 70 mgd water treatment plant, a 20 mgd water reclamation plant and a 20 mgd advanced water treatment (AWT) plant that uses microfiltration, reverse osmosis, ozonation and UV disinfection to produce water better than drinking water standards require.

During lower-demand times of the year, Scottsdale Water recharges the aquifer with the effluent from the AWT plant. The potable water is injected into 63 wells on the Water Campus, where it trickles to the aquifer, 400-500 feet underground. “You get a secondary filtration effect by putting it back this way,” Biesemeyer says. “The indirect connection is the several hundred feet of soil the water filters through before it reaches the aquifer.”

Adding irrigation

Originally, all of the AWT water was used for aquifer recharge, but the plant was expanded from 12 to 20 mgd, to provide irrigation water for golf courses. Those courses, big factors in Scottsdale’s economy, have been partners with the utility in a Reclaimed Water Distribution System (RWDS) since the early 1990s.

The golf courses invested millions in a distribution system that originally brought them raw water from the Central Arizona Project canal. When the water reclamation plant came online in 1998, the RWDS mixed raw water with reclaimed water, but over time, the golf courses became concerned that salt from the raw and reclaimed water would affect their turf.

The solution was to dilute the irrigation water with the nearly salt-free effluent from the AWT plant. The 23 golf courses that are members of the RWDS paid to expand the AWT so they could irrigation water of the quality they wanted. In winter, when irrigation demand is lower, the additional capacity of the AWT means more water for aquifer recharge.

The aquifer used to be the utility’s primary water source, but now most water comes from two surface water projects: the Central Arizona Project, which draws from the Colorado River, and the Salt River Project, which draws water from the Salt and Verde rivers. Recycled water for irrigation makes up about 12 percent of the water supply.

Each year, Scottsdale Water returns about 1.7 billion gallons to the aquifer, more than it takes out, and has qualified as a safe yield utility since 2006. The entire Phoenix area is expected to reach safe yield by 2025.

Direct reuse demo

Although Scottsdale Water has the technology for direct potable reuse, Biesemeyer doesn’t see that as a viable option for the community. “In the Phoenix area, we are blessed with a huge aquifer underneath us,” he says. “As long as we have that aquifer, it makes sense for us to recharge, because it’s a huge storage tank. We could never build a tank as big as that aquifer.”

However, the utility is working with the Arizona Department of Environmental Quality to develop permitting guidelines for regulating direct potable reuse and to get a permit for a direct reuse demonstration project.

“We certainly have the history with the 20 years of running this operation to be the one place in Arizona that could easily do this demonstration project,” Biesemeyer says. “We hope it will give the DEQ a road map to give to other people on how to go to direct potable reuse.”

Biesemeyer hopes to get the permit for the demonstration project sometime this year. For Scottsdale Water, the project will allow small direct potable uses to help the utility communicate important points about water quality.

“We like the ability to have this water for people to taste when they go through the plant, to show them that it is drinkable quality water,” Biesemeyer says. “We are also working with some local breweries to see if we can get some beer made from it to publicize that you can make recycled water to any quality you want. Water should be judged on its quality, not its history. We like to make that point. Working with breweries makes it fun.”

Power diversification

On the energy side, Scottsdale Water applied in 2014 for an allocation of low-cost renewable hydropower from the Hoover Dam and received the second largest municipal allocation in Arizona. The 50-year contract for hydropower represents about 3.7 percent of the water utility’s annual energy use. That power became available in October 2018.

In another energy diversification strategy, the utility put out requests for proposals for a solar energy installation at the Scottsdale Water Campus. The solar array, to be developed by SolarCity, is expected to provide 10 percent of the energy demand at the campus. The project, which should be under construction in 2019, includes battery storage.

“I love the concept of cleaning water with the power of the sun,” Biesemeyer says. “We’re excited about it because, with the batteries, it will be able to provide us energy at times that typically a solar array couldn’t. We need to be able to meet energy demand peaks when they occur. By having those battery units, the solar panels can work and charge batteries, so when the sun goes down we can still pull electricity from the system.”

The developer will build and own the system and will provide power to the water utility through a power purchase agreement.  

Water Academy

Scottsdale Water also communicates its vision through a twice-a-year Citizens Water Academy. “We give people about a three-hour block of time every Wednesday night for weeks. We introduce them to all the things we do at Scottsdale Water. It’s been amazingly popular. We typically have hundreds of people applying for the 30 slots every time we offer the academy.”

To attract younger operators to the industry, the utility offers apprenticeships for water treatment, wastewater treatment operators, SCADA operators and instrument control technicians. Typically four apprentices are at work at a time, one in each area. The programs take two years, and the apprentices come out as Grade 2 operators. The utility also promotes careers in the water treatment industry by going to high school job fairs.

Scottsdale Water may have a lot of recognition recently for its sustainable practices, but the practices and the vision were in place long before the awards arrived. Biesemeyer says, “I think we’ve been practicing sustainability all along.”


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