Water company to use $4.0M retained earnings for mobile PFAS treatment system after Well 15 tests over state limit

The Nantucket Finance Committee voted unanimously March 11 to recommend Article 16: a $4,000,000 transfer from the water company's certified retained earnings to purchase and install a mobile PFAS treatment system intended to treat contaminated shallow wells (Well 15 and Well 16).

Brian, finance staff, introduced the article and said the proposed $4,000,000 appropriation was changed from a borrowing to a direct use of the water company's retained earnings after discussion with the water company. "The water commission actually voted to authorize the expenditure directly from retained earnings. So we have changed that from a borrowing to a full use of retained earnings," Brian said.

Mark Bolett, director of the Wannacomet Water Company, provided a cost breakdown and technical rationale for the selected system. He said the total $4,000,000 includes equipment, site work, engineering and a building to enclose the pad: equipment currently staged in Portland, Maine, quoted at $1,400,000; site work and concrete pad at $450,000; engineering including SCADA/pump/alarm integration at $100,000; a 20% contingency applied to early site and equipment costs; and roughly $1,600,000 allocated for a building to enclose the treatment pad.

The system selected is an ion-exchange treatment train, which Mark said performs better than activated carbon for "short-chain" PFAS compounds identified in the plume from Tom's Way. "Ion exchange does a better job with the short chain PFAS... The plume from Tom's Way... the majority of that plume percentage-wise is a short chain PFAS. So we had to go with the ion exchange to take care of that plume specific," Mark said.

Mark said the immediate goal is to have the system operational by May, pending final permits and equipment delivery. He described the planned schedule: trucking equipment from Portland, assembling the pad and piping, and completing commissioning and testing. He said media replacement is expected on roughly a 4-to-5-year cycle; the transcript records Mark saying the cost to change the media would be "about $380" but the unit (thousands/dollars) was not specified in the meeting record. Disposal of spent media will be handled under hazardous-waste manifest to a licensed facility, and the water company intends to account for future replacement and disposal costs as operating expenses.

Mark also described monitoring and sampling plans. The water company found Well 15 above the 20 parts-per-trillion (ppt) PFAS limit during routine December sampling, with readings "over 50" ppt reported in the meeting. Well 15 and Well 16 are shallow aquifer wells; Well 12 is deeper and has not shown impacts. The treatment pad will be piped to allow adding Well 12 to treatment later if required; adding another filter train would be needed to treat an additional well.

The motion to adopt Article 16 was made by Joanna Roche and seconded by Jeremy (last name not specified). The roll-call vote recorded aye votes from committee members present and the motion passed unanimously. Mark thanked the committee after the vote.

Committee members asked follow-up questions about life expectancy of equipment, media regeneration, sampling frequency and sampling costs. Mark said the treatment vessels are long-lived steel tanks and the media is regenerable; he estimated laboratory testing at about $300 to $400 per sample and said the commission plans monthly sampling, possibly increasing to biweekly during commissioning or as required by MassDEP. MassDEP (Massachusetts Department of Environmental Protection) will direct long-term sampling requirements, Mark said.

The committee approved the appropriation from retained earnings rather than issuing debt, and the water company said it would retain substantial reserves after the transfer. "Using retained earnings, we're comfortable with using those retained earnings. You know, that leaves us we we're still left with 8,000,000, which is more than an annual budget for us," Mark said.