Peoria And Phoenix Water Projects Named Arizona's Best

24th St. Water Treatment Plant rehabilitation and Beardsley Road Water Reclamation Facility expansion recognized for efficiency, innovation, and reliability

The Arizona Water Association (AZ Water) has selected the City of Phoenix’s 24th St. Water Treatment Plant Rehabilitation Project and the City of Peoria’s Beardsley Road Water Reclamation Facility Expansion Project as 2026 Project of the Year award winners. The awards were presented during AZ Water’s 99th Annual Conference & Exhibition in Phoenix.

AZ Water’s Project of the Year awards highlight water and wastewater projects that set high standards for planning, design, construction, and operations. Award honorees reflect collaborative project teams and solutions that help utilities meet growth, reliability, and water quality goals while maintaining service for customers.

Water Treatment Project of the Year: 24th St. Water Treatment Plant Rehabilitation (City of Phoenix)
In operation for 70 years and centrally located in Phoenix's distribution system, the 24th Street Water Treatment Plant is a critical source of supply, helping one of the country’s fastest growing cities meet increased demands and mitigate drought conditions. Although permitted in the 1990s to treat 140M gallons per day (MGD), the plant's practical production capacity had been limited to around 120 MGD.

Rather than expanding treatment capacity through new basin construction, the City of Phoenix, Carollo Engineers, and PCL Construction focused on unlocking the plant's existing potential. Through hydraulic modeling, field testing, and plant staff input, the team identified targeted improvements including upgraded piping, new turning vanes, and expanded flow paths to reduce bottlenecks and restore the facility to its full rated capacity of 140 MGD without expanding its footprint.

The rehabilitation also included chemical unloading and safety improvements, solids-handling upgrades including a new sludge equalization basin, gravity thickener improvements, emergency dewatered cake overflow storage, and sewer discharge capacity enhancements. The project was completed on schedule and within its $10M budget, compared to the $100M a traditional basin expansion would have required.

Beyond capacity, the project strengthens Phoenix's water supply resiliency as Colorado River cutbacks approach.

"This project shows that smart investment in existing infrastructure can deliver more capacity, greater reliability, and continued water security for our customers," said City of Phoenix Project Manager Lingxiao Wang. "The project team's focus on targeted, high-impact improvements, executed with safety and continuity of service as top priorities, is a model of what's possible when owners, designers, and contractors work together toward a shared goal."

Wastewater Treatment Project of the Year: Beardsley Road Water Reclamation Facility 6 MGD Expansion (City of Peoria)
The Beardsley Road Water Reclamation Facility (WRF) has reliably served the City of Peoria since the 1990s. With population growth driving higher flows, and a citywide beneficial reuse program being planned, Peoria expanded the facility from 4 MGD to 6 MGD, rehabilitated aging assets, and kept the plant operating throughout construction.

Delivered through a progressive design-build partnership between Carollo Engineers and MGC Contractors, the project was structured in multiple packages, allowing the City to align spending with available funding, manage risk, and adapt to pandemic-related challenges.

Key upgrades span the full treatment process, including headworks, aeration basins, clarifiers, filtration, disinfection, and odor control. Arizona's first installation of InDENSE biomass densification technology improved process performance and, combined with value engineering, eliminated the need for a fifth secondary clarifier, saving approximately $5M in capital costs. Upgrading to high efficiency turbo blowers secured the city a $250,000 energy efficiency rebate while enhancements in UV and filtration technology limited the need for additional treatment trains.

The facility's effluent was upgraded to Class A+ - Arizona's highest standard for reclaimed water. A new effluent pump station was built to deliver high-quality water where it’s needed most, directly supporting Peoria's beneficial reuse program and its goal of increasing recharge capacity and reducing reliance on potable water supplies for irrigation.

"The Beardsley Road WRF 6 MGD Expansion is a great example of what can be accomplished through collaboration and innovation,” said City of Peoria Engineering Supervisor Chris Sterne. “Carollo Engineers and MGC Contractors delivered exceptional work under unprecedented conditions, successfully navigating early COVID-19 challenges including supply chain disruptions, long-lead procurement, and on-site safety constraints. By pairing capacity expansion with advanced treatment technologies and process improvements, the team not only increased system reliability and enabled Class A+ reclaimed water production but also reduced both initial capital costs and long-term operational expenses. This project reflects Peoria’s commitment to resilient, cost-effective infrastructure that supports continued growth and beneficial reuse."

About Carollo Engineers
For more than 90 years, Carollo Engineers has provided a full range of innovative planning, design, and construction management services to address the water needs of municipalities, public agencies, private developers, and industrial clients. Carollo develops robust water management strategies that leverage collaboration, provide multi-benefit solutions, and achieve sustainability and resilience. Carollo has 1,900 employees located in more than 60 offices across North America. For more information, visit www.carollo.com