New water treatment plant saves time, space

Most residents of south Gilbert and southeast Chandler probably aren't aware they're at the cutting edge of water treatment technology.

The cities are splitting the costs and benefits of the new $102.4 million Santan Vista Water Treatment Plant. It's coming online at Ocotillo Road east of Higley Road to relieve the pressure that growth put on Gilbert's water system and to give Chandler a backup source during the periodic dry-ups of Salt River Project canals.

The two cities will hold a grand opening from 8 a.m. to noon June 27.

The facility uses "ballasted flocculation" to treat Central Arizona Project water, essentially forcing the untreated fluid through a series of pipes along with a fine silica sand that forces the soil and other solids out. It's then filtered, treated and sent on its way.

The technique takes much less time and space than the process at Gilbert's older treatment plant near Greenfield and Guadalupe roads, where water treatment plant operator Paul McDowell worked for more than three years before coming to Santan Vista.

At the older facility, water sits for 10 hours while it is chemically treated. It takes 15 minutes at the new plant, a pace that keeps McDowell and its five other operators on their toes.

"Up there (Greenfield and Guadalupe) if there's a problem, you know you have a couple of hours to deal with it but here, you have to take care of it right away," he said.

McDowell doesn't think most residents being served by the new plant were aware of the switch when it began operations in early May. But he said they're getting a better-tasting product that hasn't been treated by as many chemicals, in part because the CAP water starts out cleaner than the Salt River Project water that largely feeds the northern plant.

The Santan facility is located in Gilbert and operated by that town's utilities section. Gilbert's circular town logo is even built into the pattern of the metal awning over the entrance.

But the roughly five-year process of planning and building Santan Vista has definitely been a collaborative effort, Chandler utilities manager Dave Siegel said.

"It's working out well. Gilbert has been a great partner," he said.

The Santan plant produces up to 24 million gallons per day and can be expanded to pump out another 24 million gallons. The water will ultimately be split down the middle between the two cities, but Chandler is currently getting 2 million gallons a day while testing is being completed on that city's distribution system this week, McDowell said. Gilbert's already getting all 12 million gallons of its daily share.

Both cities paid their share of construction costs through voter-approved bonds. Water user fees will cover the $1.3 million annual operating cost of the plant, which is also being split down the middle.

Plant supervisor Kurt McDavid said the facility is a "zero emission" plant. The 150 to 200 pounds of sand used every day is scooped up with giant rakes and recycled. The soil removed from the water as it's treated is trucked out to local landfills to help cover up piles of new trash.