Mansfield, MA

Addressing the Presence of PFAS with Granular Activated Carbon

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South of Boston, the suburban town of Mansfield is home to nearly 25,000 residents. Woodard & Curran’s longstanding partnership with the town began in 1996, so when sampling of one of the town’s largest water supplies detected per- and polyfluoroalkyl substances (PFAS) at concentrations above the maximum contaminant level (MCL) set by the Massachusetts Department of Environmental Protection (MassDEP), the water department turned to us for help.

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MassDEP PFAS MCL

The Cate Springs Well first tested at 22 parts per trillion (ppt) of PFAS in April 2020, and later, 27 ppt in August 2020. The well, which has a pumping capacity of more than 1,000 gallons per minute, was immediately taken off-line until a PFAS treatment solution could be implemented. Removing this significant supply source severely limits supply redundancy, so remedial actions needed to happen fast. Of three possible treatment technologies, Woodard & Curran’s drinking water and emerging contaminants experts identified granular activated carbon (GAC) for PFAS removal as the best possible option and began a pilot study to demonstrate treatment efficacy.

Woodard & Curran partnered with an independent laboratory to assist with the pilot study, which required the town to ship water from Cate Springs Well in 55-gallon drums overnight for testing. Our team established the parameters of the Constant Diffusivity Rapid Small-Scale Column Testing (RSSCT) to simulate conditions and establish design criteria for the full-scale design of a GAC treatment system. The short, 10-day RSSCT period saved a significant amount of time and money by eliminating the need to conduct a months-long pilot study while still informing the final design parameters and providing our team with sufficient information to estimate capital and ongoing operations and maintenance costs. This also helped identify a critical path procurement process for equipment with long lead-times to ensure the team could meet the aggressive project schedule and get the well back in service.

From pilot to project implementation

The design team used the pilot test results to develop technical specifications and design criteria. This enabled the town to pre-procure GAC treatment vessels, saving approximately six months as compared to a typical procurement process. With the treatment vessels in fabrication, the remainder of the new facility was designed over the winter, including structural, electrical, emergency power, replacement well pump, controls upgrades, stormwater management, and site improvements. Permits from MassDEP, Massachusetts Environmental Policy Act (MEPA), and the town were obtained in early spring of 2021, clearing the path for construction to begin in summer 2021.

As the design team developed plans and specifications, Woodard & Curran’s funding team helped the town identify, apply for, and secure critical funding for the project. This included a PFAS treatment design grant from MassDEP and Drinking Water State Revolving Funds for construction costs.

More than a year into the pandemic, the project team knew uncertain supply chain issues and increasing labor shortages could impact the project delivery time. Rather than bid out all the work at once, the team sought a contractor to pour the concrete slab first so the foundation would be ready for the arrival of the four GAC treatment vessels. Each vessel is approximately 12-feet in diameter and 25-feet high, weighing approximately 25,500 pounds empty and 153,000 at full operating weight. Each vessel holds about 40,000 pounds of GAC, which was also procured in advance and stored on site to ensure access to the carbon media after the process piping between vessels was complete.

The four GAC vessels arrived on flatbed trucks and a crane was used to place each one on the prepared slab. Installation of the treatment process was completed on June 6, 2022. The treatment building to house the new equipment is currently under construction and on schedule to be completed before the end of 2022.

PFAS Treatment System Installation

This time lapse video captures the delivery and installation of four GAC treatment vessels. The building to house the treatment system is currently under construction.

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PFAS is a pressing matter for water utilities         

Across the country, PFAS is being detected in public drinking water supplies and private wells. The increase incidence of PFAS detection has prompted many states to set aside funding for critical infrastructure improvements to address PFAS in public water supplies. The design grant from MassDEP that our funding team helped secure totaled $200,000. Our team also helped obtain a $4.5 million loan from the Drinking Water State Revolving Fund for construction of the PFAS treatment system. The loan is eligible for 0 percent interest, and the program will award 20 percent of the total amount as principal forgiveness.

The town received final regulatory approval to activate the new treatment system on the heels of the new health advisory for PFAS released by the U.S. Environmental Protection Agency (EPA) on June 15, 2022. Woodard & Curran’s drinking water treatment experts are ready to assist other communities and water suppliers across the country address PFAS and prepare for anticipated federal regulatory measures.

Project Team

Carol Harris Senior Client Manager Drinking Water
Srivalli Sukuru PE Project Manager Drinking Water
Steve Robbins PE, LEED AP Technical Manager Drinking Water
Sienna Roberge Engineer Drinking Water
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