The Madison Water Utility says it can effectively remove toxic “forever chemicals” from a contaminated East Side well for as little as $136,000 per year, though the utility is continuing to evaluate its options.
That’s significantly less than the cost of other filtration technology evaluated.
The utility commissioned Madison-based consultant TRC Environmental to evaluate treatment options for Well 15 on East Washington Avenue, which was shut down in 2019 after tests showed elevated levels of PFAS, likely the result of groundwater contamination from the nearby airport.
The report studied two filtration technologies, granular activated carbon and ion exchange resin, and concluded the carbon filtration would be most cost-effective. Estimated operating costs for the systems ranged from $48,000 to $733,000 per year, depending on the level of contamination and desired outcomes.
The Department of Natural Resources this week notified the company that it violated two sections of state code by waiting more than 15 months to report the leak.
While both technologies filtered PFAS to levels that state health officials consider safe for human consumption, the carbon system also removes two volatile organic compounds, tetrachloroethylene (PCE) and trichloroethylene (TCE), that are present in Well 15 but currently treated with a different system.
Water quality manager Joe Grande said the recommended treatment system would cost about $670,000 to install and could do the job for $136,000 to $300,000 per year, depending on the level of PFAS contamination allowed.
The lower-range estimate would effectively remove 90% of all PFAS and meet the proposed state health standard of 20 parts per trillion for two compounds, PFOA and PFOS. The higher estimate would eliminate 90% of each individual PFAS compound.
The funding came from the state’s annual allocation of $105 million in federal low-income energy assistance. The state expects to receive about $110 million in additional energy assistance funding this year.
Last year the utility said PFAS had been detected in each of its 22 wells, though none were above the state’s proposed drinking water standards for the two most studied compounds.
Utility spokeswoman Amy Deming said the board is still in the process of evaluating the cost-effectiveness of treating water from Well 15 or other alternatives, such as drilling a new well or reducing demand.