Tighe & Bond is currently working with Aquarion Water Company of New Hampshire to upgrade the Mill Road Water Treatment Plant. The plant is served by six individual wells, and our team has designed a centralized treatment plant to simplify operations, improve operator safety, and increase system reliability. This project is also part of Aquarion’s larger capital improvement efforts for improved corrosion control, as well as compliance with potential revisions to the Lead and Copper Rule.
In addition to the project’s design challenges, PFAS have been detected in 15 of the 16 wells supplying Aquarion’s Hampton System, with the highest concentrations at the Mill Road wellfield. Aquarion evaluated alternatives for PFAS treatment, identifying granular activated carbon (GAC) and ion exchange (IX) as potential options. Initial bench scale testing was completed, with the results used to develop a preliminary design for a full-scale PFAS treatment facility at Mill Road. Pilot scale testing was conducted to better refine breakthrough and operating costs associated with both short chain PFAS and the recent New Hampshire regulated PFAS.
To refine the bench scale testing results, Tighe & Bond completed a pilot test, which was used to update the preliminary design of the Mill Road PFAS treatment facility. Our work included a pilot-scale testing plan, sampling support, and close coordination with laboratories for PFAS analysis. The pilot scale testing was completed over 12 months, treating approximately 200,000-bed volumes of water.
In addition to the new centralized water treatment plant with bulk chemical storage and feed, the project included 5,000 LF of new distribution mains and 3000 LF of raw water transmission mains. The upgrades also included virus inactivation through the use of a pipeline contactor and pH adjustment capabilities for improved corrosion control that were not feasible with the existing facility.