A new treatment plant is supplying an Arizona Native American tribe with clean drinking water.
The Ak-Chin Indian Community put the facility into operation last fall, providing water to more than 900 Ak-Chin community members and serving the tribe’s businesses, including its Harrah's Ak-Chin Casino in Maricopa, south of Phoenix.
The new plant has also won awards. The tribe received the 2013 Water Treatment Project of the Year Award from the Arizona Water Association for its use of technological innovation.
The surface water treatment plant emerged from geological necessity and practicality.
Jayne Long, capital project manager for the Ak-Chin Indian Community, said before the surface water plant was built the tribe relied on groundwater wells. She said the catalyst came when the tribe drilled a new well that was low-producing and hit bedrock at 600 feet.
Long described hitting bedrock as "game over" for water drilling. She said the tribe decided to search for the deepest bedrock tables on its reservation and ran into another problem.
“At the same location, where the surface water plant is, we had the well driller come out and he drilled," Long said. "And, he drilled and he drilled and he drilled...we went down well over 2,000 feet" without finding potable water.
The Ak-Chin community receives 75,000 acre-feet of water a year from the Colorado River. That’s about 24 billion gallons piped through a series of canals to the reservation.
Long said using the river water was a logical choice because it doesn’t need to be treated for arsenic or nitrate like the groundwater on the reservation. Arsenic naturally occurs in Arizona groundwater and nitrate is caused by agricultural runoff from the tribe’s farming operations.
Long said Ak-Chin’s allotment of Colorado River water meets the needs of tribal members and its agricultural sector.
“It works out to about 160 acres of cotton a year that we would be taking out of production in order to support this plant," Long said. "Ak-Chin currently farms about 16,000 acres, so literally it’s a drop in the bucket ... the farms don’t even miss what we are using in order to supply this.”
Carollo Engineers was hired to design the surface water treatment plant.
Dave Sobeck, senior vice president for the company, said tribal leaders wanted to use the latest and greatest for the facility.
“The community had made it very clear that they wanted to go with a technology that was very robust, that provided a very high-quality, consist drinking water, and one that would have a longer-term outlook to it," Sobeck said. "It provided them with a lot of future flexibility both in terms of expanding the facility itself very quickly and cost effectively."
The new surface water treatment plant uses membrane technology to filter water. Long said to think of it as having a straw with pours on the outsides of it.
“So you're pulling the water through the sides of the straw, and anything you don’t want going in is sticking to the outside of the straw and you're pulling the fresh water through via a vacuum," she said.
The membrane filters out things like bacteria, viruses and particles to produce clean drinking water.