May 24 2022Share

Phoenix's Blue Bank Partnership fosters innovation in water conservation

By AMWUA Staff

Our ten desert cities are always looking for practical and innovative ways to be more efficient with water use, including creating partnerships and programs to help residents, businesses, and industries be more efficient.

A recent example of these efforts occurred in Phoenix when Mayor Kate Gallego and the Phoenix City Council members voted unanimously to make funding available to companies interested in using leading-edge technology to save water and protect the environment.

The new 'Blue Bank' partnership is between the City of Phoenix, the New Venture Fund's BlueCommons project, and the Bonneville Environmental Foundation's Business for Water Stewardship (BWS) program.

In many municipalities, industrial water use is a substantial portion of total water demand. Yet, industrial conservation is often hard to achieve due to industrial customer demands that cannot be easily adjusted. But many industrial users share at least one type of high-water demand that can be addressed through common conservation approaches - low-energy efficiency wet-cooling systems. Relatively simple upgrades to existing cooling systems can substantially increase the number of cycles during which the same water can be used in cooling.

Cooling Tower At Sky HarborA highly successful, large-scale cooling tower water treatment technology pioneered at Phoenix Sky Harbor International Airport is the basis of this grant program. Cooling towers are used in industry-scale air conditioning systems – like those at the airport. Due to the hard water in the Phoenix area, corrosion happens quickly, clogging the system with mineral deposits.  The deposits reduce the efficiency of the systems, causing them to use more water; they can also require harsh chemicals to remove. By using ingenuity and experimentation, engineers at the airport found that the results were dramatic by combining a water softening system with an environmentally friendly disinfectant generator on the cooling towers at Terminal 3, 4, and the Rental Car Center. There was a massive reduction in the chemicals needed to keep the pipes clean and a savings of 31 million gallons of water in Terminal 4 alone. Another significant improvement is that now cooling water can cycle through the towers 3.5 to six times before being discarded.  

Now that the initiative has received Council approval, Phoenix staff will start building the program, which includes identifying companies that are potentially ready to adopt this technology, while BlueCommons and BWS will provide loans to qualified companies that want to incorporate cooling tower projects in their buildings and campuses. The hope is to create a rotating funding mechanism for future projects and future water savings. 

To print or save this week's blog, a PDF version is available HERE.

For over 50 years, the Arizona Municipal Water Users Association has worked to protect our member cities' ability to provide assured, safe, and sustainable water supplies to their communities. For more water information, visit

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