The University of New Hampshire (UNH) owns and is responsible for operations of a water treatment plant (WTP) that serves the entire campus as well as the Town of Durham, NH. The University replaced the aging facility with an efficient, state-of-the-art, 26,000-square-foot WTP designed to treat and deliver up to two million gallons of high-quality drinking water per day.
The new plant, delivered under a collaborative design-build contract, is the first of its kind in New Hampshire and features a unique treatment process designed to accommodate three very different source waters, as well as a significant population flux. UNH has upwards of 13,000 undergraduate students on campus between September and May, adding to Durham’s year-round population of approximately 16,500.
The new WTP sits adjacent to College Woods, a 250-acre area of woods, streams, and fields used by UNH and area residents for recreation and research. The design team took care in situating the facility to minimally impact the natural resources. While the new plant required some trees to be cut, the team coordinated with the University’s facilities staff to properly balance protection of existing trees with space requirements for the new WTP. While the plant’s design had to maintain the same treatment capacity, the new facility was designed to have full redundancy of all equipment and provide enough space to facilitate maintenance and operations for the foreseeable future. Woodard & Curran designed the new treatment building with a capacity of 2.0 million gallons per day (MGD). The facility is equipped with three residuals lagoons, an open process area that is visible through interior windows, and a training lab for engineering students to perform experiments. Unlike the old facility, the new plant site is located above the 100-year flood plain and will better handle the varied range of water characteristics from the three water sources.
The new treatment process includes rapid mix, flocculation, plate-settler clarification, multi-media filtration, and disinfection. Additionally, there is corrosion control, pH adjustment, and fluoridation. There is also a supplemental chemical feed system and multiple dosing points for seasonal manganese treatment using potassium permanganate. Below grade, concrete tanks include two backwash supply tanks from which water is pumped for filter backwashing operations, two disinfection contact time tanks and three independent clearwells, all of which provides significant redundancy in the overall treatment process.
The design-build approach allowed for stakeholder input throughout the project. The campus planning department reviewed iterations of conceptual designs, constructability reviews were conducted by the general contractor and operability reviews were performed by both Woodard & Curran’s operations group and existing UNH WTP operations staff. Throughout the entire project, this process was fully transparent with close collaboration between the University, owner’s project manager, and design-build team. The project was expedited by the alternative delivery method with construction starting as final design details were finalized, which also reduced the amount of time the old facility needed to remain operational.
As construction neared completion, UNH elected to engage a contract operator for the new facility. After an additional procurement stage, the project effectively turned from a design-build delivery into a design-build-operate contract with Woodard & Curran’s operations and management team assuming the contract. The existing relationship allowed for an easy transition of operations staff under the Woodard & Curran umbrella from the old facility to the new facility, which began distributing reliable, high quality water in March 2020.