23-05-2025
How does Ann Arbor clean PFAS from its drinking water? City officials explain.
PFAS, or "forever chemicals," were first detected in Ann Arbor's drinking water in 2014. Two years later, the city performed a follow-up investigation and detected PFAS in the Huron River.
The river supplies the city with 85% of its drinking water.
"We traced it up to upstream manufacturing facilities and wastewater treatment plant discharges," said Ann Arbor Water Treatment Services manager Molly Maciejewski. "So, it was really industrial discharges that caused it, but we also know that there could be other sources of PFAS in the Huron River."
PFAS are highly stable, man-made chemicals used in many items. They're typically used to repel water, oil and grease from surfaces. PFAS spread easily and do not biodegrade naturally, making cleanup a challenge.
"Michigan was one of the first in the country to actually sample all of the drinking water supplies," said Abigail Hendershott, the executive director of the Michigan PFAS Action Response Team.
Hendershott said PFAS are all around us. They're found in clothing, furniture, cleaning products, outdoor gear, cosmetics and more.
"Most everybody in the country is going to have some concentrations of PFAS already in our blood because of the widespread use of PFAS in our everyday society," she said.
After extensive testing, officials at the Ann Arbor Water Treatment found an effective solution.
"We use granular-activated carbon filtration," said drinking water quality manager Becky Lahr. "So, you can see here the media inside the filter. The water travels from the top down through the filter, and the PFAS gets stuck within the media."
Lahr told CBS News Detroit the method filters out PFAS to below detectable levels in the drinking water.
"We are constantly monitoring the water quality before and after this process to make sure it's working right," Lahr said.
"Ann Arbor has been very aggressive in their actions, and we, of course, applaud them for that because they're being very proactive in protecting their residents," said Hendershott. "We want to make sure that the residents who are drinking this water are protected long term, that we're not just protecting for one or two chemicals, but we're protecting for the whole suite of PFAS chemicals."
