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April 2020

AZ Water Association names White Tanks Expansion 2020 Water Project of the Year

The White Tanks Regional Water Treatment Facility Expansion and Process Upgrades has been selected as the AZ Water Association’s 2020 Water Project of the Year. Archer Western was the contractor responsible for the expansion and process upgrades to EPCOR’s water treatment plant in Surprise, AZ. Located near the foothills of the White Tank Mountains, this plant provides potable water to communities in the west-central portion of Maricopa County. The expansion portion of the project consisted of adding a new 38 MG raw water reservoir, additional raw water and finished water vertical turbine pumps, 33 MGD UV disinfection units, an additional DAF basin, addition of an enhanced treatment process, two additional solar drying beds, two gravity media filters, wastewater clarifier and chemical feed upgrades, and an electrical and control building. The plant's treatment process increased its total firm capacity from 13.4 MGD to 26.7 MGD and increased its total capacity from 20 MGD to 30 MGD.

The enhanced treatment process upgrades to the plant involved the design and construction of the first CoMag® ballasted clarification system in Arizona. The system uses an inert iron ore by-product called magnetite which when used along with chemical coagulant, settles out solids as much as 30 times faster than conventional treatment. It also utilizes magnetic recovery drums which recover up to 99% of the magnetite ballast to reduce operational cost. CoMag® was specifically implemented to address high turbidity water events, such as heavy rain and storm runoff in the summer, which can result in a surge of particles and mud. These surges can disrupt the plant’s treatment ability and put the plant under stress to continue to provide compliant drinking water. Though magnetite clarification has been used before in the U.S. for wastewater, this project is the first in the country to use the CoMag® system on the water supply end.

AZ Water is a 501(c)(3)nonprofit educational organization founded in 1928 with a membership of 2,700 water/wastewater professionals dedicated to preserving and enhancing Arizona's water environment. Although AZ Water is an independent organization, it also serves as the Arizona section of the American Water Works Association (AWWA) and the Arizona member association of the Water Environment Federation (WEF).



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