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Water summit

Leaders look at treated effluent as major source

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Posted: Monday, November 1, 2010 11:00 pm | Updated: 8:18 am, Thu Mar 24, 2011.

Experts and elected officials from across southern Arizona met Friday, Oct. 29 at Oro Valley Town Hall to discuss the future of the area's most precious natural resource: Water.

While surface and groundwater remain in short supply, arid Southwestern states are flush in reclaimed water. It's a resource many at the conference agreed was largely untapped, with the potential to greatly reduce water usage.

"It is one of those resources that's a steady, dependable supply," said conference speaker Steve Olson of the Arizona Municipal Water Users Association.

Reclaimed water, also called effluent, has been treated and cleaned of bacteria and microorganisms. Effluent supplies grow as populations swell. In modern wastewater treatment facilities, effluent emerges almost indistinguishable from tap water.

In Pima County and other areas of the state, reclaimed water is used to irrigate golf courses, public parks, schools and roadway medians. More than 20 of the 39 golf courses in eastern Pima County use reclaimed water for irrigation, according to the Tucson Water Department.

Reclaimed water also could be used in other applications, including recharge.

Chris Avery of Tucson Water said effluent recharge could become a greater use for reclaimed water as more infrastructure is put into place.

Uses for effluent, such as restoration and creation of riparian habitats along washes and dry riverbeds, already occur throughout the county. The county's Roger Road Treatment Facility has been pouring tens of thousands of acre-feet per year into the Santa Cruz River.

Uses like this already contribute indirectly to groundwater recharge, but Avery said effluent would not be used for drinking water or "toilet to tap."

"At some point, we have to find where the additional water resource will come from," Avery said.

Reclaimed water and its uses featured heavily in the discussions about long-term strategies.

Another issue discussed was the use of gray water.

Val Little with the Water Conservation Alliance of Southern Arizona said the group has been advocating for gray water use for years. Unlike effluent, gray water is non-sewage waste residential customers produce through washing machines, showers and faucets. The water is redirected from sewer lines and used for irrigation purposes on the producer's property.

Some homebuilders in Southern Arizona have begun to install gray water harvesting fixtures on new homes. Homes also can be retrofitted to utilize gray water.

According to the Water CASA website, a household of four people can produce an average of 70 gallons of useable gray water each day.

Other discussions focused on groundwater replenishment, renewable water resources and the challenges the Central Arizona Water Project faces.

Arizona has a 2.8-milion acre feet annual allocation of Colorado River water. Fourteen pumps and three tunnels deliver the river water more than 300 miles across the desert and up more than 2,000 feet in elevation.

To pump all that water across the desert takes extraordinary amounts of energy.

"The Central Arizona Project happens to be the largest energy user in Arizona," said Warren Tenney of Metro Water and the Central Arizona Water Users Association.

Much of that energy comes from the Navajo Power Generating station in Northern Arizona. Bur federal regulators have in recent years set their sights on the power plant, saying the facility produces too much emissions, causing haze.

Tenney said CAP officials are willing to invest some $48 million to make improvements to the plant. Environmental Protection Agency officials likely would require upgrades to clean the air around the power plant that could cost more than $1 billion, Tenney said.

"That could mean we would have to double or triple our water costs," he said.

Perhaps summing up the water situation for most communities across the West, Tenney said: "Any new source of water is going to be expensive — there's no more cheap water in the state."

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