City of Pasco Wastewater Treatment Plant Improvements

Wastewater treatment plant outfall replacement

City of Pasco Wastewater Treatment Plant Improvements

Increasing Wastewater Treatment Capacity Through Rehabilitation and Expansion

HDR has been supporting the City of Pasco with implementing its Wastewater Treatment Plant Facility Plan which assessed current and future treatment needs while meeting and exceeding state and federal requirements for the safe return of water to the Columbia River.

We performed third-party construction management and full-time, on-site construction observation for phases 1 and 2. We worked closely with the design engineer to construct these improvements, which included managing and maintaining overall task and subconsultant budgets, providing timely work products, providing timely notice, ensuring timely and accurate invoicing, documenting changes, communicating and coordinating construction activities, and leading construction meetings.

These projects at the Pasco’s Wastewater Treatment Plant represent a complete upgrade of the liquids and solids systems within a fully functional and operating facility, including a new outfall to the Columbia River.

Phase 1 will increase the capacity of the WWTP by rehabilitating and constructing new liquids process facilities and installing the upland portion of a new 42-inch-diameter outfall.

Phase 2 consists of improvements and modifications of the solids process to the City’s existing municipal WWTP. This portion consisted of the rehabilitation/construction of new solids process facilities, the construction of 1,600 linear feet of a new 42-inch-diameter, high-density polyethylene outfall piping, and installation of a multiport diffuser, of which 1,250 linear feet were constructed within the river.

Services will also include performing construction closeout.

Wastewater treatment plant outfall replacement
City of Pasco

Pasco, WA
United States



Project of the Year (2024)
Environment, $5-$25 Million Category
American Public Works Association, Washington Chapter