When water treatment plants (WTP) in three communities needed upgrading and PFAS was found in the source and treated water, the Tri-Town Water Commission decided to replace the three existing plants with a new 12.5 MGD plant – the Tri-Town Regional WTP.

Our approach

We are providing engineering design and architectural services for the new plant that will be located adjacent to the existing facility in Braintree.

To ensure the new plant will be capable of reducing the PFAS concentrations to compliance levels, we conducted analysis and performed pilot testing of treatment technologies. Our in-house laboratory services evaluated various granular activated carbon filter medias and reviewed filter sizing to satisfy Massachusetts Department of Environmental Protection’s requirements for the removal of PFAS. In parallel, we performed separate rapid small-scale column tests that assessed the performance of a targeted novel adsorbent media using the same filtered water.

Outcome

Our analyses resulted in granular activated carbon in a gravity filter arrangement being selected as the most efficient and cost effective PFAS removal media given the dual drivers of both PFAS and disinfection by-product compliance. The selection of the media resulted in a redesign of the filter to achieve sufficient contact time and extended the life of the carbon to provide convenient change out frequencies for operations.