Solutions

The PFAS we are dealing with is the result of groundwater impacted by decades of development in the town, not by our treatment processes. PFAS are now being detected because advancements in testing enable detection at much lower levels than ever before.  

We anticipated, prior to beginning our testing in April of 2021, that we might be out of compliance, given that industry trends to date have been that 20-30 percent of supplies tested positive for PFAS. To be proactive, we began interviewing engineering firms in case their services were needed on short notice.

We have engaged MassDEP. Based on this engagement, we submitted a draft public education and public notification document using MassDEP's templates, which they reviewed and approved.  This notice went out to the public on August 18, 2021.

We have engaged an engineering firm to assist us in developing a solution to the problem. This firm has experience in reducing PFAS concentrations in other communities.

We held a public forum on September 15, 2021, in partnership with MassDEP to educate the public about PFAS and answer questions. We thank MassDEP for their participation in this forum as it was very informative and many questions were answered.

The quickest, easiest, and most reasonable solution seems to be to perform a demonstration study on one of the three mixed-media filters at the Pond Street plant, replacing the media with granular activated carbon (GAC). GAC works by adsorbing the PFAS, drawing it out of the water. Our engineers have prepared and, on September 17, 2021, submitted a permit application with MassDEP seeking their approval of this demonstration study. If approved, we will replace the existing media with GAC and run for a month to assess performance. The demonstration study will indicate if replacing the media in one or more filters will get the Pond Street WTP water below the state standard. The study will also provide an estimate of the GAC filter media's lifespan. In anticipation of DEP's approval of our plan, we have purchased and received the media needed and are ready to install once we receive approval. 

If replacing the filter media in the Pond Street WTP is not effective, we will need to design, permit, procure, and build additional external GAC filters at Pond Street. This will necessitate taking the parking lot at the facility and relocating the DPW offices to another site.

On September 21, 2021, MassDEP approved the Town's proposed plan to replace the filter media in one filter at the Pond Street WTP with granular activated carbon (GAC) and to conduct a demonstration study on the effectiveness of GAC in reducing PFAS in the Pond Street WTP finished water. Work is expected to commence the week of September 27, 2021.

From September 28, 2021, to September 30, 2021, DPW personnel removed old filter media from the Pond Street #3 filter, inspected the filter underdrains, and installed new GAC filter media. The work was inspected and approved by our engineers, and the filter went into service on October 5, 2021.