Release Date: May 6, 2026
PLEASANTON, Calif., May 06, 2026 – Zone 7 Water Agency’s Stoneridge PFAS Treatment Plant has earned a National Recognition Award from the American Council of Engineering Companies (ACEC) as part of its 2026 Engineering Excellence Awards (EEAs) The award places the facility among the nation’s most outstanding engineering achievements of the year, recognizing the project’s innovation, technical excellence, and positive impact on public health in the Tri-Valley community.
The EEAs are an annual celebration of engineering excellence, honoring projects that demonstrate technical creativity, bold problem-solving, and engineering’s unique ability to improve our world. The project was celebrated at the EEA Gala Dinner & Award Program on Tuesday, May 5 in Washington, D.C.
Designed by Carollo Engineers and built by Conco-West, Inc., the Stoneridge PFAS Treatment Plant is the first in Northern California to deploy an ion exchange (IX) system for the removal of PFAS (per- and polyfluoroalkyl substances). PFAS are synthetic chemicals found in everyday consumer products and industrial applications, including food packaging, non-stick cookware, and firefighting foam. Though water agencies are not responsible for introducing PFAS into the environment, they have been tasked with removing these contaminants from affected water sources as federal and state regulators establish stricter standards.
“The Stoneridge PFAS Treatment Plant represents an important investment in protecting groundwater quality and ensuring a safe and reliable drinking water supply for the Tri-Valley community,” said Zone 7 Water Agency General Manager Valerie Pryor.
The $16.3 million facility, located at the Stoneridge Well in Pleasanton, treats up to 6.5 million gallons per day, serving more than 267,000 residents and businesses across Dublin, Pleasanton, Livermore, and San Ramon. Construction was completed in under 12 months from Board approval, with the facility delivering treated water in fall 2023, an achievement made possible through an accelerated design-build approach.
Carollo served as lead designer, guiding the project from bench-scale testing through final commissioning. The firm conducted extensive Rapid Small Scale Column Tests (RSSCTs) to evaluate granular activated carbon and IX media options, selecting the most effective and economical approach for long-term PFAS removal. The design integrated IX pressure vessels, cartridge filtration, rerouted site piping, a new booster pump station, chemical system modifications, and a state-of-the-art electrical building with advanced instrumentation and controls.
“Earning a National Recognition Award from ACEC is a tremendous honor for the entire project team,” said Carollo Vice President and Project Manager Peter von Bucher. “This project exemplifies what’s possible when an agency has the vision to act decisively on an emerging public health challenge. We’re proud to have partnered with Zone 7 Water Agency and Conco-West to deliver a first-of-its-kind solution for Northern California.”
In addition to protecting public health, the facility was designed with long-term sustainability in mind. For example, cartridge filtration upstream of the IX vessels extends resin life by removing particulates before they reach the media, reducing resin replacement frequency, minimizing waste streams, and lowering operational costs over time.
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Media Contact:
Cameron McWilliam
Senior Public Relations Manager // Carollo
[email protected]
