Water Project

Tri-Town Regional Water Treatment Plant and PFAS Removal

Tri-Town Water District Board Braintree, Randolph, and Holbrook, MA

Solution Overview

Tri-Town Regional Water Treatment Plant and PFAS Removal

Client:

Tri-Town Water District Board

Business Challenge:

  • Design, construction, and permitting of a new water treatment plant (WTP)

Solution:

  • Construction of a new 12.5 million gallons per day (MGD) WTP and redundant sub‑aqueous transmission mains
  • Organic removal and treatment of six per- and polyfluoroalkyl substances (PFAS) over maximum contaminated level (MCL) of 20 parts per trillion (ppt)

Results:

  • Conceptual design, designer selection, design services oversight, and funding program permitting

Challenge

Tri-Town Water District Board manages the shared water supply of the Great Pond Reservoir bordering the towns of Randolph and Braintree. This Reservoir is the source of all the drinking water for the towns of Randolph, Holbrook, and Braintree. Braintree and the Joint Randolph/Holbrook Water Board own and operate individual WTPs on the Lower Reservoir portion of the Great Pond. While the Towns have proceeded with needed upgrades over the years, a new facility is required to replace each of the treatment plants. It was determined the most cost-effective approach was to construct one Tri-Town Regional Water Treatment Plant as opposed to two separate plants. Environmental Partners (EP), Apex Companies’ Infrastructure Solutions platform, was engaged to support the Tri-Town Water District Board through design and permitting of the new treatment plant.

Solution

The construction of the Tri-Town plant will include a new 12.5 MGD dissolved air flotation (DAF) regional water treatment plant and redundant sub-aqueous transmission mains. The plant is being designed for organic removal and to treat a set of six PFAS detected at concentrations over Massachusetts Department of Environmental Protection (MassDEP) MCL of 20 ppt. The state-of-the-art WTP is being designed for the injection of potassium permanganate followed by potassium hydroxide for pH adjustment prior to reaching the pre-oxidation tanks. As the water exits the pre-oxidation tanks, polyaluminum chloride and cationic polymer are added for coagulation. After being processed in a rapid mix tank, the water flows into two‑stage flocculation tanks, and then into four dissolved air flotation trains followed by five granular activated carbon (GAC) media filters for removal of particles and PFAS compounds.

Results

Current phases include oversight of design services, permitting, and technical review of the 30, 60, and 100 percent designs of the WTP. EP will continue to provide technical oversight during construction of the project including full time resident project representation and startup services. The anticipated completion date for this project is late 2025.

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