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Sewage often becomes fertilizer, but the issue is it's tainted with PFAS


The water from our sinks, showers and toilets contain the chemicals known as PFAS. As WBUR's Barbara Moran explains, all those so-called forever chemicals are going into wastewater treatment plants. The question now is, where do they go from there?

BARBARA MORAN, BYLINE: It's barely sunrise, and I've already put a lot of stuff down the drain - shampoo, cold coffee, soap, all kinds of stuff.

LAURA ORLANDO: What gets into wastewater is just about everything that we use in our society.

MORAN: Laura Orlando is a civil engineer and senior science adviser for Just Zero, a nonprofit focused on waste.

ORLANDO: Because it's the pollution sink for what's out there, which is a big deal when we're talking about PFAS.

MORAN: Orlando says because PFAS chemicals are in so many household and industrial products, they end up in wastewater. And in Greater Boston, that wastewater ends up at the Deer Island Treatment Plant, one of the largest in the country. The tanks of sewage sludge are so big there, you have to take an elevator to the top.

DAVID DUEST: So now we're above 124 feet.

MORAN: Plant director David Duest says the sludge is about the consistency of a frappuccino. And that hum you hear - it's the sound of a giant mixer stirring it.

So right under our feet is, like, how many gallons of...

DUEST: About 3 million gallons of sludge that spends about 22 days on site before it actually gets pumped to our pellet plant for conversion to a fertilizer.

MORAN: Recycling sewage sludge into fertilizer seems like a good idea, and about half the sludge in the U.S. ends up this way. Janine Burke-Wells is the executive director of the Northeast Biosolids and Residuals Association.

JANINE BURKE-WELLS: These are organic materials. So they have carbon, which is great. We're putting carbon back into the soil. There's a lot of nutrients. And when you see what the material does for the soil, it is pretty amazing.

MORAN: The problem is all those toxic PFAS chemicals. They get concentrated in the sludge and, therefore, the fertilizer. And there's no cost-effective way to get them out. There are no federal rules that say how much PFAS in fertilizer is too much and just a few states with guidelines. Only one state - Maine - has banned the use of sludge-based fertilizers altogether. Environmental advocates, like Just Zero's Laura Orlando, argue that every state should follow Maine's lead.

ORLANDO: There is no safe concentration of PFAS. And so adding it to soil as a fertilizer - it's a disconnect from the reality of the harm of this family of chemicals. And so the logical thing to do is just not spread it all over the place.

MORAN: But the sludge has to go somewhere, and the other options are not great. Sending sludge to a landfill or burning it costs more money, wastes nutrients and gives off greenhouse gases. And all these methods leave PFAS behind. Sonya Lunder is the senior toxics policy adviser for the Sierra Club, and she says the best long-term solution is to shut off the PFAS pipeline.

SONYA LUNDER: We need to stop making and using these chemicals in unnecessary products because they pollute the planet at every stage that they pass through.

MORAN: This is a point where both waste industry advocates and environmentalists agree, and the chemical industry may be getting the message. Manufacturing giant 3M says it will stop making PFAS by the end of 2025. Public health scientists say that's great. But there's still concern that without better regulations, these chemicals could simply be replaced by new ones that are just as bad.

For NPR News, I'm Barbara Moran in Boston.


Barbara Moran