Denver Water’s $520-million Northwater Treatment Plant (NTP) is capable of treating 75 million gallons of water per day. Built on a 183-acre site next to the Ralston Reservoir northwest of Golden, Colo., the plant will leverage influent pressure to generate electricity through a 427-kW hydroturbine, becoming a net energy producer on an annual basis. The site was purposely chosen to sit at a lower elevation, allowing for the NTP to utilize influent pressure to produce energy. Space is reserved in the headworks for a second hydroturbine, and regular plant treatment flow will determine when installation is cost-effective to continue offsetting the facility’s power draw.

Although the plant will connect to the electrical grid upon opening, it will be capable of future modifications to go off grid, using battery storage if deemed feasible and necessary. NTP incorporates treatment process adaptability, an important component for building resiliency against possible future variations in source water quality due to post-wildfire contamination. In addition, 20 acres are reserved adjacent to the facility for a future solar farm.

Photo courtesy Kiewit

The project team built several treatment buildings into the hillside, minimizing visual impact and reducing the energy load required for cooling and heating. The NTP design was split into eight packages to facilitate working with local vendors, including more than 50 subconsultants. This supported a sustainable local workforce and access to the expertise of local organizations with targeted solicitations from minority and women-owned businesses. As the project team grew to include eight prime design firms and a construction manager at-risk, Jacobs established a co-location facility capable of housing up to 300 staff.

After the pandemic, the contracted precast manufacturer experienced a loss of more than 100 production staff, which threatened the project schedule by multiple months. To mitigate this risk, Kiewit and its major concrete subcontractor PCL deployed their own concrete crews to the precast manufacturer’s plant and produced the remaining wall panels in collaboration with precast plant crews. After nearly six years of construction, the team delivered the facility on time and below budget.