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MassDEP: 54 POET systems installed, bottled water provided at 33 private-well locations as PFAS interim response
Summary
MassDEP said it has 54 point-of-entry treatment systems in place and supplies bottled water to 33 additional private-well locations while POETs are installed; GAC systems are used, require quarterly sampling and may need radon pretreatment or more frequent change-outs if co-contaminants such as 1,4-dioxane are present.
MassDEP staff described practical measures the agency is taking to address imminent hazards from PFAS in private water supplies, including point-of-entry treatment (POET) installations, interim bottled water and technical guidance for treatment design and maintenance.
"We currently are maintaining 54 point of entry treatment systems, and we provide bottled water to an additional 33 locations at this time," John Ziegler said. Installed POET systems generally use two carbon vessels in a lead'lag configuration with sampling ports for raw, mid-stream and effluent water. MassDEP said it typically uses bituminous-coal granular activated carbon (GAC) but has used coconut-shell carbon in places where effluent discoloration was a concern; staff noted coconut carbon may not last as long as bituminous coal.
POET systems are sampled generally on a quarterly basis, and carbon is changed out when PFAS are detected in the mid-fluent sample. Staff cautioned that co-contaminants can change maintenance needs: practitioners reported that systems treating PFAS alone may need maintenance about once per year, while the presence of 1,4-dioxane has required two to three additional GAC change-outs.
Ziegler also raised radon as a pretreatment consideration after encountering radon at a POET site. He recommended regional offices consider radon testing during design and noted contractors suggested pretreatment for radon concentrations exceeding 5,000 picocuries per liter because radon can reduce GAC capacity and create disposal or radiation concerns for spent carbon. "Our contractors have recommended that we consider radon pretreatment at, radon concentrations, exceeding 5,000 picocuries per liter," Ziegler said; he added that ORS guidance-level numbers (ORSG) for radon are 10,000 pCi/L for consumption.
MassDEP advised that reverse-osmosis treatment for private homes can be used but cautioned that Title 5 (310 CMR 15) prohibits discharge of reverse-osmosis wastewater; a municipal discharge option should be discussed with the local sewer authority. Staff also flagged design implications when leachate or landfill plumes (e.g., salt-waste or landfill-related constituents) are present and said DEP coordinates with landfill and salt-waste program data when designing treatment.
Next steps for practitioners: follow forthcoming CAM protocol for method 1633, expect guidance updates to sampling-and-analysis documents, and consult regional MassDEP staff about design choices (pretreatment, treatment media and disposal) when multiple contaminants are present.
