Prescott completes $42M wastewater treatment plant

An aeration basin, right, and multiple buildings are part of the City of Prescott’s recent expansion of the wastewater treatment plant located near the airport. (Matt Hinshaw/The Daily Courier)

An aeration basin, right, and multiple buildings are part of the City of Prescott’s recent expansion of the wastewater treatment plant located near the airport. (Matt Hinshaw/The Daily Courier)

PRESCOTT -  The largest public works project ever completed by the City of Prescott recently became operational.

Over the past month or so, the new $42 million Airport Wastewater Treatment Plant expansion has been going through a start-up procedure, according to Prescott Utilities Manager Joel Berman.

That culminates about two years of work by contractor PCL Construction/Fann Environmental. Construction began in October 2012, and work is currently wrapping up. Landscapers were on site Wednesday, adding final touches.

Berman noted that the expansion "provides redundancy" in the plant's capabilities.

The project increases the Airport Plant's capacity to 3.75 million gallons per day. The plant previously had a capacity of 1.2 million gallons, and was treating about 1.1 million gallons. "Our old plant had reached capacity," Berman said. "We didn't have any capacity available."

The project included a new aeration basin for treatment of the wastewater, as well as a number of new buildings for operations and other purposes.

"We built a modern plant that meets all of the current regulations," Berman said.

Among the new features of the expanded and improved plant will be an upgrade in the quality of the treated wastewater (effluent) that comes out of the plant. While the plant previously treated its wastewater to a B+ quality, Berman said the new plant's effluent would reach an A+ quality.

The city reuses its effluent for a variety of purposes, including recharging it back into the ground for credits in its water portfolio.

The city's other wastewater treatment plant, near Sundog Ranch Road and Highway 89, continues to produce a B+ quality effluent, Berman said. Currently, that plant treats about 2.58 million gallons per day.

Through the years, the Prescott City Council has had numerous discussions about the possible consolidation of the city's wastewater treatment at the Airport Plant, which is located off Melville Road in an industrial area in northeast Prescott.

While the council has made no decision on centralizing its wastewater treatment, Berman said the design for the recent expansion at the airport plant allowed for that possibility. "It was designed so that we can add pieces to it," he said.

The contract with PCL Construction/Fann Environmental totaled $35.3 million, while the total expansion project will end up costing about $42.6, including engineering, land acquisition, and permitting.

To pay for the project, the city obtained a WIFA (Water Infrastructure Finance Authority of Arizona) loan. Prescott Budget and Finance Director Mark Woodfill said the WIFA amount totaled about $45.8 million, which he said represented the top limit of the loan.

"It is all done as a projection (of the final cost)," Woodfill said, adding that the city would borrow only the amount necessary to cover the actual cost of the project.

The 20-year loan (at 2.95-percent interest) is being paid back through user rates and impact fees, Berman said.

The necessary wastewater treatment improvements first came up in a 2009 wastewater treatment master plan. At that time, consultants identified about $88 million in needed wastewater treatment improvements.

That led to a 2010 rate analysis and six-year capital improvement program, which included recommended projects. In late 2010, the council approved a three-year rate increase to pay for a portion of the needed improvements.

Berman said another rate study is currently under way for possible future water and sewer rate increases.

The City Council is expected to receive a utility-rate update at its Oct. 7 and 14 meetings, Berman said, and public hearings likely will take place in November.

Follow Cindy Barks on Twitter @Cindy_Barks.