The facility is being built to meet more stringent regulatory requirements enacted by the state of Utah in 2016. The change propelled city managers to identify ways to reduce phosphorus levels in effluent discharges in order to comply with the regulations.

They settled on the Westbank biological nutrient removal system used with UV disinfection. The project scope also includes a solids dewatering facility, a chemical feed facility and a new electric substation with four standby generators.

On track to reach substantial completion in July 2026, the project’s use of CMAR has already netted the city considerable cost and time savings, the team says, and the new reclamation plant is expected to achieve Platinum status in the Envision sustainable infrastructure certification program.

The team installed wick drains to allow water to move and the soft soil to become more consolidated.
Photo courtesy of Sundt/PCL

“CMAR allowed us to be dynamic enough to be able to head off a lot of the inflationary costs before they actually [arrived], so it’s a huge, huge benefit for the department,” says Jason Brown, deputy director and chief engineer on the project.

From the project’s inception, the team has had to deal with the COVID pandemic, earthquakes, inflation and “all kinds of disruptions in the world that caused us a lot of challenges on an almost weekly basis,” Brown says.

Case in point: The original plan was to use steel piles for soil stabilization. And steel was used in a few structures before prices for the material started escalating as a result of supply shortages related to the pandemic.

“We were going to put an obscene amount of steel into the ground, and we were finding that the prices just started going up,” Brown says.

The team then thought they would preload steel needed for piles on the site. “But even then, we were getting quotes that were only good for the next 48 hours,” says Ragan Bryce, JV construction manager for PCL.

So the team, working together, pivoted; they decided to switch to auger cast piles, which don’t require as much steel.

The team used the piles on two structures, “and just the material savings alone was right at $1 million,” Bryce says, adding that auger cast piles typically take less time to put in place than steel, and in this case, the switch shaved two months off the schedule.

In another instance, the team improved upon the DPU’s initial plan for keeping the existing plant operational while construction continued. The reclamation facility is being built on land that previously was occupied by concrete-lined digester dry beds to remove water from the sludge.

However, the city’s temporary dewatering system to replace the dry beds proved to be expensive, and ineffective, according to PCL.

The JV team then proposed installing two of four newly procured pieces of dewatering equipment into the temporary system, which proved to be more effective than the previous setup.

DPU’s Brown says that the use of value engineering and collaboration among team members has been eye-opening.

“I don’t think that there was another method that we could have chosen that would have got this project to where it’s at right now,” he says.

Manny Diaz, deputy director for the joint venture and international regional manager for water and wastewater at Sundt, adds that the mindset among different parties working on CMAR projects tends to be different than what he’s seen on projects that use traditional delivery models.

“I just came out of a hard-bid job. And one thing I’ve seen here [ that’s different] is the one-project mentality where everybody chips in. It’s not what’s best for the contractor, or for the designer; it’s what’s best for the owner and for the project.”

Once the drains were installed, the team brought in 2 million tons of dirt and spread it across 33 acres. It was left there for eight months to further stabilize the soil.
Photo courtesy of Sundt/PCL

Site Challenges

The soil conditions at the site were another challenge. And, again, collaboration among team members saved time and money, says DPU’s Brown.

“The only thing that’s consistent about our soils is that it’s bad across the whole site, horribly bad,” he says. The soil, like in many parts of Utah, was particularly soft and could lead to settling of structures built atop it without sufficient stabilization.

The project team decided to stabilize the soil using a combination of stitching and soil surcharge.

The team first drilled holes into the soil and installed more than 1,000 wick drains (prefabricated vertical drains) to allow water to move and thus accelerate the consolidation of the soil.

Then, approximately 2 million tons of dirt were placed about 30 ft high across a 33-acre area. The dirt sat for eight months, settling and further consolidating the soil before it was removed.

“The great thing about those wick drains,” says PCL’s Bryce, “is that if you just do preload by itself and put the dirt on it, it could take two to four years for that weight to consolidate.” The wick drains reduced that time to eight months, he says.

The quality of the soil on site is typical for Utah, the project team says, and is susceptible to settling without intervention.
Image courtesy of Sundt/PCL

Sustainability Focus

Much of the soil that was removed from the surcharge was then saved for other uses on the project. Some of it also was taken to other city projects, including a nearby highway project.

Recycling the soil in this way will result in credits for Envision certification, which is a goal for DPU and aligns with the sustainability goals of Salt Lake City Mayor Erin Mendenhall (D), Brown says.

Mendenhall has served as mayor since 2020 and has made sustainability and climate change adaptation key priorities.

Sustainability has been a primary focus of the project from the beginning, Brown says, noting that the project team was encouraged to identify ways “in every component” of the project to make the facility more sustainable and eligible to achieve Envision Platinum status.

In addition to recycling the soil used for surcharge, the team crushed the concrete that was removed during demolition of the original drying beds and reused it on other parts of the site. The effort created 27,00 cu yd of crushed concrete.

The substitution of the auger cast piles for steel rebar and the recycling of dirt and concrete allowed the team to avoid 98% of the waste that would otherwise have gone to a landfill, Brown says.

Structural concrete work continues at secondary clarifiers and BNR structures. The project required more than 90,000 cu yd of concrete.
Image courtesy of Sundt/PCL

Choice of Treatment Process

The original wastewater treatment plant used an activated trickle filter treatment process that was not designed to reduce nutrients such as nitrogen and phosphorus. With the 2016 regulations in place, DPU needed to identify a solution that would reduce nutrient levels in effluent discharges. Moreover, the original plant was more than 65 years old and was past its useful life.

As a result, DPU convened a panel of local, regional and national experts to evaluate different treatment processes and identify a solution that would work. They selected the Westbank biological nutrient removal process, which splits the flow of influent to allow nitrogen to be removed before anaerobic treatment begins. The process consists of a reactor with seven different zones.

Once the water is denitrified, it goes through an anaerobic treatment first and then is followed by an aerobic process to absorb phosphorous.

“It’s been proven in other climates similar to ours, and that’s why we wanted it, and it removes the [nutrients] that we needed to get out of the water,” Brown says.

DPU was able to obtain a $300-million WIFIA loan that will save the city about $100 million in interest over the life of the loan. “That was a huge win for the city [and] for the rate payers to get that loan,” he adds.

The team is installing a biological nutrient removal process that includes both anaerobic and aerobic digestion
Image courtesy of Sundt/PCL

Nearing Completion

At press time, the project was about 86% complete, and at 85% of the initial cost, Sundt’s Diaz says. Of the more than 90,000 cu yd of concrete required for the project, the team has approximately 500 cu yd to complete the platforms and other ancillary structures.

Issues do continue to pop up, but the team seeks to work together to address them.

For example, with the recent escalation in copper costs, the team “was able to get out in front of that” by procuring most of the electrical cables and wires needed for the project before it was ready to be installed, Diaz says.

Additionally, DPU itself had some bumps in learning how to implement a project using a CMAR approach. “It took us a while to get the right frame of mind,” Brown notes. But while DPU’s use of CMAR has not been without its own learning trajectory, it has been key to the project’s success, he adds.

With the size and complexity of projects continuing to grow, PCL’s Bryce thinks that CMAR is going to become more widely used.

“You’re trying to do a half-a-billion-dollar project that spans three to five years. Trying to do that as hard-bid is tough. This alternative delivery process helps you manage the risk that everybody has.”