Tres Rio Water Reclamation Facility Nutrient Recovery Project

Tucson, Arizona

Award of Merit

OWNER: Pima County Regional Wastewater Reclamation Dept.


GENERAL CONTRACTOR: Quanta Electric Power Construction


Pima County’s wastewater reclamation department contracted with a European company to use an innovative system designed to improve the plant’s sustainability. The system captures phosphorus as struvite, which can then be sold as a fertilizer additive. The process, referred to as the nutrient recovery system, has improved plant operations, reduced maintenance and operating costs, decreased chemical use and ultimately will provide a new revenue stream. The technology used is called NuReSys, and this is the first time the process has been used in the U.S. 

Project challenges included creating the first struvite sequestration system in the country and constructing it during the pandemic. The team relied completely on 3D modeling tools to design the system and employed design-build delivery to balance cost and quality.

The project’s three new tanks and equipment building provide easier access and maintenance for operations crews while eliminating safety hazards. The design complements the four publicly visible zones that surround the facility and features the muted desert tones to integrate the structures seamlessly into the rest of the 160-acre site.

To make all of this happen, the Tres Rios team had to navigate European Union regulations and apply them to the more technical requirements of OSHA standards in the U.S. The completed system has reduced ferric chloride costs by $375,000 annually and lowered hauling costs by nearly $700,000 a year.