In 2006, Arizona issued a ruling that in order to prevent contamination of the Lower Santa Cruz River, Pima County would need to meet stringent nutrient discharge requirements by 2015. As a result, Pima County developed a $720-million Regional Optimization Plan to modernize existing facilities and services as well as build the $172-million Agua Nueva Water Reclamation Facility.

In December 2010, CH2M Hill was selected to design, build and operate the Agua Nueva facility. As the DBO firm, CH2M Hill has been the unifying force throughout preliminary design, permitting and construction, says Greg Fischer, vice president of CH2M Hill. The company also completed acceptance testing and will provide operations and maintenance for 20 years.

Agua Nueva treats 32 million gallons of wastewater daily to produce A-plus effluent. Its treatment process includes new headworks, influent pumping and a combined flocculation/grit removal system. Additional components include dissolved air flotation clarification, tertiary filtration and chloramine-based disinfection. A five-stage Bardenpho activated sludge secondary treatment system is enhanced with step-feed aeration, the first facility in North America to manage complex secondary effluent ammonia in this manner, according to CH2M Hill.

The project team included more than 150 onsite staff working more than 29 months to deliver almost 1 million labor hours with no lost-time accidents. The project had a total of five recordable incidents.

"We are very proud of the project's resulting 1.09 total recordable incident rate," Fischer says.

Crews achieved these results through the creation of an integrated team environment and project-wide programs applied to all team members regardless of their affiliation, he says.

"We tried to get away from the word 'subs' because they had to be 'partners' to be part of this culture," he adds.

Judges praised the use of mobile devices for site communication, which Fischer says was made functional by providing WiFi access to every corner of the site.

According to CH2M Hill, the project was completed eight months early, $2 million below contract and $77 million below the $240-million budget cap.

Agua Nueva Water Reclamation Facility


Key Players

General Contractor/Lead Design Firm CH2M HILL, Tempe, Ariz.

Owner/Developer Pima County Regional Wastewater Reclamation Dept., Tucson

Subcontractors Swaback Partners, Scottsdale, Ariz.; Archer Western Contractors, Phoenix; West Point Contractors, Tucson; McDade Woodcock, Centennial, Colo.; Structural Grace Inc., Tucson; J2 Engineering and Environmental Design, Phoenix