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Randolph Water Analysis: PFAS 2022Feb. 22, 2022: The Tri-Town Water Board allowed for a tour of our two water treatment plants (permission granted to Councilor Gordon and Select Board Member Watkins, but not to members of the public, and with the agreement of "no pictures"). Here are our notes from that "tour", so the public sees the full story, and can make informed decisions.Resolution on PFAS filtersBased on the water plant tour, Councilors Gordon and Clerger will introduce a Resolution on PFAS filters at the March 14 Town Council meeting. Please come and comment -- we recommend investigating how the water plant can implement a partial PFAS filter right now, and propose a solution for the next couple of years (replace the top half of the filter material to minimize risk of old pipes and drains). Click to download Resolution in MS-Word Resolution on PFAS testingSince the Water Forum last summer, we've been pushing to get some PFAS testing -- and the Town Manager did get 7 test sites set up with the state DEP. At the water plant tour, we heard that Braintree is conducting its own PFAS testing. Councilors Gordon and Clerger will introduce a Resolution on PFAS testing to supplement the state testing with sites that were missed -- we propose three new sites (see image at upper right) and propose that additional sites be determined later. Click to download Resolution in MS-Word 1) How can we add PFAS filters?Coming out of the Randolph & Holbrook water forums, the conclusion seemed to be that adding PFAS filters would (a) require a new building and (b) cost over a million dollars for (c) only a two-year interim period. Based on the water plant tour, we think all three of those conclusions are incomplete. The complete story is that while the Randolph/Holbrook water plant can't do exactly what was done in Braintree, we CAN add PFAS filters that will reduce our PFAS content substantially -- ensuring that we stay below the 20 ppt state-designated health level. The Braintree water plant replaced their existing filter material, which didn't filter out PFAS, with Granulated Activated Carbon ("GAC"), which does filter out PFAS. They replaced all filter material in all five of their filter tanks, which reduced their PFAS level from 21 ppt to near 0 ppt. The GAC filters are several feet deep; the water comes in at the top, filters through the GAC material, and drains out at the bottom, with some PFAS adsorbed onto the GAC in between. Over time, as the GAC adsorbed more PFAS, Braintree's output PFAS level has crept back up, and is now around 10 ppt. So Braintree is "recharging" the material in two of their five tanks (replacing the GAC with cleaned and recycled GAC) -- this project is currently out to public bid. The issue in the Randolph/Holbrook water plant is that our tanks are older and more fragile, so replacing the filter material runs the risk of damaging the tanks and piping. In particular, the drains at the bottom of the tank are at most risk, so we should avoid exposing the bottom -- it's less risky to only replace the top half of the filter material. In the water forums, the assumption was "all-or-nothing" replacement -- and it's true that we can't do it all, like Braintree did, without a new building to house new tanks. But we CAN replace the top half of the filter material with GAC, and expect half the result that Braintree got. That would mean our PFAS level is reduced from around 20 ppt to around 10 ppt, and that reduction might last a year or two below the 20 ppt health cutoff level. Braintree appropriated about $680,000 for replacing all five filters with GAC, which included removing the old filter material and purchasing the new GAC material. That total did not include the "recharge" taking place now -- that's expected to cost somewhere around $50,000 per tank. Randolph/Holbrook has 8 somewhat smaller tanks with about the same total filter material; it should be roughly half the cost to remove and replace half the existing filter material. That means roughly $340,000 to get started, split between the two towns. If the new water plant construction takes longer than the expected two years, we might want to invest another $100,000 for GAC recharge in 2024. All of the costs are eligible for ARPA funding -- in other words, there is no property tax increase nor water rate increase for this expense. 2) Who decides on adding PFAS filters?Our real decision here is whether it's worth $340,000 to cut our PFAS levels in half until the new water treatment plant comes on line. That figure is just an estimate, and an accurate engineering cost might be calculated -- but it's not over a million dollars, as we previously understood. Our decision also includes the risk that the existing tanks could suffer damage during the GAC filter process. The worst-case scenario is that one of the eight tanks is shut down entirely for several weeks. The tanks are somewhat independent, so if each tank is half-filled with GAC separately, the risk would only be one tank failing. And the risk is reduced by only replacing the top half of the filter material. The people of Randolph and Holbrook should make this decision, based on the complete story of the costs, benefits, and risks. There are four government entities -- representing the people and therefore listening to the people -- to implement installing partial PFAS filters in the Randolph/Holbrook water plant:
3) How can we get additional PFAS testing?Everything above is about reducing our PFAS levels after PFAS has already gotten into our reservoir. We can also look to reduce the amount of PFAS entering our reservoir in the first place. It's possible to test each input source -- the small streams that feed into the reservoir -- and identify which stream has high PFAS levels. We could then try to identify how that stream gets contaminated, or implement some sort of system to reduce the PFAS input from that stream. At the urging of the Town of Randolph, the Massachusetts DEP (Department of Environmental Protection) recently began PFAS testing at 7 source points in Randolph around our reservoir. Those test results take several weeks to get back from the state lab, and the state may repeat the process periodically. That might find some high PFAS levels in source streams. The Town of Braintree is performing additional testing on their own, in points around Braintree. That includes the Farm River, which feeds the reservoir from the northeast. We think all three towns should share PFAS testing results -- Selectman Watkins and Councilor Gordon will follow up to ensure that the test results are shared by all three towns. In addition, we would like to propose that the Randolph and Holbrook perform additional testing on our own at the following testing sites:
We came up with this preliminary list of testing sites by looking at maps for stream flows. We would welcome input from the public on additional testing sites in Holbrook and Randolph. After gathering input from residents, Selectman Watkins and Councilors Gordon and Clerger will introduce parallel Resolutions to the Holbrook Select Board and Randolph Town Council to initiate PFAS testing on the sites in their respective towns.
Randolph Water Analysis: PFAS(notes from 2021)
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