The Tri-Town Board of Water Commissioners (Tri-Town) represents the towns of Braintree, Randolph and Holbrook. Tri-Town was created through legislation in the late 1880’s to manage the jointly utilized water supply known as Great Pond bordering the towns of Randolph and Braintree. The Great Pond Reservoir System consists of the Upper Great Pond Reservoir, the lower Great Pond Reservoir, and the Richardi Reservoir.
The Great Pond Reservoir System is the source of 100 percent of the drinking water for these three communities. Tri-Town maintains the reservoir dam system and provides overall management of the water supply system. Braintree and the Joint Randolph/Holbrook Water Board own and operate individual WTPs on the Lower Reservoir portion of Great Pond.
The Town of Braintree and the Joint Water Board (Randolph/Holbrook) have completed a number of upgrades at each WTP over the years; however, it has come to a point in time where a new facility is required to replace each of the treatment plants. Rather than construct two separate plants the communities determined the most cost-effective approach was to construct one Tri-Town Regional WTP (TTRWTP) on available land adjacent to the town of Braintree’s WTP.
As the Owner’s Project Manager, EP represents Tri-Town Water District for the project. Services provided include project oversight and all services associated with project management of a publicly constructed water treatment facility. This multi-million dollar project includes a new 12.5 MGD dissolved air filtration regional water treatment plant and redundant sub-aqueous transmission mains. The plant is being designed for treating PFAS6 over the new Massachusetts Department of Environmental Protection (MassDEP) MCL of 20 ppt and organic removal. Funding for the project comes from the Massachusetts Department of Environmental Project Drinking Water State Revolving Loan Fund.
The plant is being designed for injection of potassium permanganate followed by potassium hydroxide and the addition for pH adjustment prior to reaching each pre-oxidation contact tanks. As the water exits the pre-oxidation tanks it will be dosed with poly-aluminum chloride and cationic polymer for coagulation. It will then be mixed in the rapid mix tank and flow into two-stage flocculation tanks and then into four dissolved air flotation trains followed by five GAC media filters for the treatment of PFAS chemicals. Final addition of potassium hydroxide adjustment and sodium hypochlorite for disinfection will be applied prior to discharge into the Chlorine Contact Tank/Clearwell structure. Two sets of finished water pumps are required. One to pump to the Braintree water distribution system, and one to pump through a subaqueous HDPE transmission main into the Randolph/Holbrook water distribution system.
EP’s first task included a review of the Pilot Plant Study conducted in 2004 to obtain approval from MassDEP on the approach for treatment, reviewing 25% design plans, conducting constructability and value engineering workshop, preparing a new preliminary conceptual design layout, and creating a detailed probable cost estimate and schedule for the overall project.
EP’s initial services included oversight of conceptual design, designer selection, design services, permitting, funding support, and technical review of the 30, 60, and 100 percent designs of the WTP. EP has been contracted to continue providing owner project manager services including technical oversight during construction of the project and full-time resident project representation and startup services.
Construction began November 2022 with the anticipated completion date of late 2025.