Our team provided design services for upgrades to the existing 12.5 million-gallon-per-day (MGD) Persigo Wastewater Treatment Plant (WWTP) in Grand Junction. We are also providing independent cost estimating and construction phase services for the capacity expansion to 15 MGD.
Our team was to evaluate how the expansion of the WWTP would be the best approach for the city. Upon review of the plant’s hydraulics, we found several pinch points that would require significant improvements before the planned expansion could proceed. Expansion upgrades included additional bioreactor capacity, new blowers, aeration system and blower building. Also included in this phase of expansion was the replacement of the existing ultraviolet (UV) system, new screens, screening handling and grit processing. The conversion of the means to dewater digested solids to a centrifuge included a new multistory dewatering structure and storage area with the potential to convert to composting.
Major structural changes included demolition and redesign of the UV building’s concrete structure to accommodate new process design and equipment, along with coordinating pre-engineered metal building (PEMB) supports and precast electrical building foundation and supports.
This project also features enhancements to the plant’s electrical infrastructure, upgrading medium-voltage systems to support plant expansion. Key improvements include new switchboards, motor control centers (MCCs), harmonic filters and an emergency generator to improve power reliability. Fiber-optics coordination and power distribution modifications provide seamless integration with the upgraded treatment processes.
The project is the largest for the city to date and the first step in its $110 million master plan. As part of the construction manager at risk delivery, we worked with the contractor to develop a work breakdown structure for organizing independent cost estimates (ICE). We also conducted a plan flip to verify project scope, directed reconciliation meetings, and led the estimate reconciliation session. Our efforts gave the city confidence that the project cost was accurate and in line with market conditions.
We are providing full-time resident project representative services, with construction set for completion by spring 2026.