Read the full article by Fil L. Fina III (Water & Wastes Digest)
“The town of New Windsor restored drinking water production contaminated by PFAS with granular activated carbon.
A group of over 4,700 compounds used in the manufacturing of non-stick and waterproof coatings, personal products and fire suppression foams, per- and polyfluoroalkyl substances (PFAS) can often be found at airports or air force bases. Also known as ‘forever chemicals,’ these long molecular chain fluoride and carbon chemicals are resilient and exposure is believed to be linked to numerous health risks.
Since the 1940s, PFAS has been used in commercial products. We come into contact with PFAS through the things we buy, like furniture and clothing, but according to the EPA, most drinking water contamination results from living near facilities that handle products containing PFAS, like manufacturing plants or airports/air force bases. For the town of New Windsor, New York, the contamination source is still under investigation, but one possibility is the Stewart Air Force Base, located about 5 miles northwest of the aqueduct that sources the wells. Fire suppression foams have been used at the base for decades.
For local government officials and decision makers, recent media coverage of the issue has created a need for some high school chemistry: parts per trillion, compounds, molecular chains, adsorption and absorption are all commonly used terms. As films like Dark Waters or Erin Brockovich remind us, no one wants to get this stuff wrong.
Unfortunately, PFAS chemicals are still considered an ’emerging contaminant.’ Federal oversight with clearly defined ‘safe’ and ‘unsafe’ thresholds has been absent, leading many states to set their own standards and regulatory consensus remains elusive. While many means and methods for treatment are being discussed, it’s hard to know what is proven to work.
The Challenge: Restore Drinking Water Quickly
New Windsor use three groundwater wells for water supply (the largest yielding municipal wells in the state of New York). Following the development of these wells, the Butterhill Water Treatment Plant was constructed, with a design capacity of 6.45 million gallons per day (mgd). The plant was designed to treat elevated levels of iron and manganese, which was identified during well development. The plant went on line in August 2018, though distribution to customers did not start, in full, until October 2018.
Water samples taken by the NYS Department of Health in September 2018 tested positive for PFAS (PFOA and PFOS, in particular), though town officials and representatives were not told of these results until February 2019 (verbal confirmation only of a positive result was provided at that time). Additional water samples were collected the following day, with test results on those samples reported to the town on April 1, 2019. Again, verbal confirmation of a positive test result was provided at that time. On April 4, 2019, town officials were first provided with a written report of test results. This was the first indication the Town had as to what the specific levels of PFOA and PFOS were in the water that sourced the Butterhill Wells. The levels detected were below the EPA public health advisory (PHA) and even the proposed maximum contaminant level (MCL), but out of an abundance of caution for its residents, the town shut down the well field and returned to the Catskill Aqueduct for its source of supply…”