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Gilbert WTP Facility: Largest Single Clean Water Investment in Arizona History

 |  Mining & Industrial

As water shortages continue to pose challenges across the Southwest, long-term, sustainable access to clean water is a priority for municipal clients. Driven by our Industrial Group’s expertise in water/wastewater, Sundt has made its mark in this critical sector.

Sundt teams set one of the new belt presses in place at the site of the Town of Gilbert's North Water Treatment Plant Facility.
Sundt teams set one of the new belt presses in place at the site of the Town of Gilbert’s North Water Treatment Plant Facility.

In Gilbert, Arizona, Sundt/PCL, a Joint Venture is upgrading and reconstructing the North Water Treatment Plant (WTP) Facility which receives its water from the Salt River Project’s (SRP) Eastern Canal. The project is the largest single investment in clean water in Arizona history. The necessary upgrades are a result of watershed and wildfire driven raw water quality challenges, population growth, existing facility failures and the need to maximize renewable water resources.

When completed, the plant will provide more than 70% of Gilbert’s available water supply, increase production from 45 million to 60 million gallons per day and capacity by over 100,000 residents. The upgrades will result in a facility that can reliably produce water that is compliant or even cleaner than national water standards, reduce utilization of non-renewable resources and better adapt to water quality challenges. These improvements will result in cleaner, longer-lasting, more sustainable water for the Town of Gilbert.

Science Experiment

Sundt’s Water Treatment résumé with the began in 2005 with phase one of the Greenfield Water Reclamation Plant. It continued in 2007 with construction of the new Santan Vista Water Treatment Plant and the Santan Phase II expansion in 2016.  “It’s exciting to perform on this important facility and have the opportunity to continue our relationship with the Town,” said Senior Project Manager Mike Schlabach. “By the time all phases of the Gilbert North WTP upgrades are complete, we will have established a more than 20-year relationship with the Town’s Water and Wastewater Treatment groups.”

Before construction work began on the facility, Gilbert ran a pilot program to evaluate which water treatment processes would serve the facility best. “In conjunction with the client, Corona Environmental Consulting and Sundt put together a scaled, simulated model of the plant and ran thousands of different water treatment scenarios over the course of one year,” Mike said. “There’s a huge variability in water quality, even when it’s from the same source. The pilot program effectively tested the water throughout each season of the year and during periods of lighter and heavier rainfall. Basically, it was a giant science experiment.”

Sundt assisted in the installation of the interconnecting piping for the pilot program. By the end of the one-year experiment, the team was able to determine which processes and chemicals would treat the water most effectively.

Every Last Drop

In April 2023, the Sundt/PCL team celebrated substantial completion of GMP 1, which included the installation of three new belt filter presses and the construction of a FRP baffle wall system in the north reservoir. This system assists and enhances disinfection byproduct removal. They also constructed two new gravity thickeners.

One major enhancement to the facility includes the replacement of multiple, large drying beds with belt filter presses. This process offers many benefits, including capturing more water, making the facility more sustainable, and enabling a faster drying process for sludge and debris. This new equipment eliminates the need for drying beds, which take up a substantial amount of space. This newly reclaimed space will be the home of the new water treatment plant construction, maximizing existing space use at the facility.

“The entire scope of the dewatering facility, most notably the belt presses, was built for the purpose of replacing what were the existing drying beds,” Project Engineer Lukas Heesch explained. “A process that took about 90,000 square feet and several days to over a week to complete, can now be accomplished in a 15,000-square-foot area within a single day.”

Looking Forward

In the coming months, Sundt/PCL will prepare for the demolition and construction of the new 60-MGD water treatment plant. The service upgrades and expansion to the plant will allow for a 50-plus year service life, ensuring residents of Gilbert have reliable access to water and creating ongoing prosperity for the rapidly growing town.

Learn more about Sundt’s resume of water/wastewater work here.