Like many communities, Nampa, a city of roughly 100,000 in Idaho’s Treasure Valley, was facing new phosphorus and temperature limits on its wastewater effluent. In 2010, the city began what would ultimately evolve into a 20-year effort to modernize its wastewater treatment plant.
To help with the planning and upfront regulatory and permitting efforts, the city brought in Brown and Caldwell as the program manager. “But [they] set it up so that we could get other engineering firms and the contractors involved to make sure that we’re getting the best overall delivery for the city,” explained Matt Gregg, client services manager with Brown and Caldwell. A diverse team, including Jacobs (formerly CH2M Hill) as the design engineer and Ewing Company as the contractor, was assembled to support a collaborative process throughout the project. “We wanted to make sure we were getting the best ideas and really delivering for the city on what they were looking for,” said Gregg.
In the early days of the project, Gregg noted, they weren’t really sure what the long-term solution would be. “We didn’t have a permit yet, we didn’t have a TMDL yet, but we knew we needed to start making progress.” In order to limit the risk of stranded investment while also minimizing the rate impact to customers, the project team opted for a phased approach.
Phase one comprises three projects. “The first project we did in that program was Project Group A, which is a new aeration basin, switching over the existing aeration basins to phosphorus removal, and then adding an intermediate pump station,” said Gregg. “It wrapped up last year and set the stage for everything to come.”
The remaining two project groups in phase one are nearing completion, and phase two is underway — and it’s causing a lot of excitement. “The city, back in 2017, decided to pursue Idaho’s largest recycled water program. They’ll be discharging class A recycled water in a nearby irrigation canal to serve the community and some of its agricultural partners in the area,” he said. “We’re in the design on the first couple of projects and then we’ll be doing Idaho’s first ever progressive design-build project for wastewater starting sometime next summer.”
The work done on Project Group A has garnered some well-deserved recognition, including as project of the year by the American Public Works Association Rocky Mountain Chapter, and best water/stormwater project by the American Council of Engineering Companies Idaho Chapter. It also received an honorable mention in EPA’s prestigious Pisces Award program.
The city’s phased approach to the massive upgrade project contributed significantly to the recognition it has received — and Gregg credits the city’s outreach efforts for leading to that strategy. “One of the things the city has done really well is to engage its stakeholders throughout the process,” he said. A Nampa Wastewater Advisory Group with about 50 members was established. “We presented to them all the technical things we were doing, asked for their feedback, and asked them to be our decision-making body throughout this.” Ultimately, they came up with the phased approach to limit capital spending and keep rates lower longer.
Another impressive aspect is that work must be done while the plant is running. It’s like “changing an airplane engine in flight,” Gregg noted. “We’re able to do that [because] of the proactive planning and collaboration throughout the project. I think that’s what really set this one apart.” WW