
Photo: Jonathan Wiggs/Globe.
A New Haven, Connecticut, carbon-capture start-up is testing its concept at this sewage facility in Fall River, Massachusetts. Limestone gets mixed in with waste water at the bottom of the tank to draw out carbon.
Nowadays most of us don’t think much about sewage. Out of sight, out of mind. But I regularly read novels that were written before indoor plumbing, and I often think about how awful those chamber pots and outhouses must have been. I feel grateful for the people who do think about sewage today.
Kate Selig reports at the Boston Globe about a New Haven, Connecticut, company turning sewage into a tool for fighting climate change.
“At the edge of a picturesque bay in this historic city,” she writes, “a deep waste water tank harbors an unlikely climate experiment.
“Near the base, a narrow tube spits out a milky stream that’s as thick as roux. The liquid, a mix of treated waste water and a naturally occurring mineral, is swirled in with the sewage. The combination kick-starts chemical reactions that pull carbon dioxide, a greenhouse gas that drives climate change, into a harmless bicarbonate ion.
“CREW Carbon, a startup founded in New Haven, is betting that this simple combination could turn dirty water into a powerful climate solution. It has partnered with waste water treatment plants along the East Coast, including the facility in Fall River, to put this approach into action. As a bonus, municipalities often find that limestone is a cheaper and more effective way to treat waste water than conventional methods. …
” ‘We don’t need massive new infrastructure or subsidies,’ said Joachim Katchinoff, the company’s cofounder and CEO. ‘And because our process delivers real operational and cost benefits, it creates a win-win for utilities and for the planet.’ The company grew out of research at Yale and was founded in 2022 by Katchinoff and Noah Planavsky, a geochemist and Yale professor. …
“When the water flows out of the plant, the company says, the dissolved ions eventually make their way to the ocean, where they can be stored for thousands of years. Katchinoff estimated that a single treatment plant can remove thousands to tens of thousands of tons of carbon dioxide annually. The startup sells carbon removal credits, a way for companies to pay to offset their climate pollution. CREW Carbon is one of the first companies to deliver credits in New England.
“The municipalities benefit as well. Some waste water treatment plants see cost savings and increased safety for workers by using limestone instead of chemicals for controlling pH. The limestone also can yield cleaner water flowing out of the plant. And in some cases, CREW Carbon is sharing revenue with the treatment facility from the carbon credits it sells. …
“The company’s first partnership was with the local utility in New Haven. Since then, it has grown to have six full-scale projects, most located on the East Coast. It delivered its first carbon credits in the spring, making it the first company in the world to have done so using waste water alkalinity enhancement, as the method is known. Alkalinity is a measure of the water’s ability to neutralize acids.
“In the coming years, the startup has committed to delivering about 70,000 tons of carbon dioxide removal, the equivalent of taking over 16,000 gas-powered cars off the road for a year, to a coalition of companies that includes Alphabet and McKinsey. …
“On a recent day, Jonathan Mongie, a project manager for Inframark, which operates the Fall River plant, leaned over a tank where waste water treated with limestone was being disinfected.
“ ‘I can see deeper than we’ve ever seen before,’ he said, observing the clarity of the water. The limestone increased the amount of solid particles in the waste water separated out using gravity. The plant was already meeting stringent discharge standards, Mongie said, but the limestone has improved the cleanliness of the water flowing into the bay. …
“Planavsky, the Yale professor, said CREW Carbon’s approach is not a silver bullet for the climate crisis. Instead, he said, it could be part of a future integrated approach where many industries each do their relatively small part. (Though Planavsky is a cofounder, he does not receive any money from the company.)
“Some scientific questions remain about waste water alkalinity enhancement, especially what happens after the water leaves the treatment plant. Tyler Kukla, a research scientist at CarbonPlan, a nonprofit that analyzes climate solutions, said the chemical reactions that occur within the waste water plant are well understood and take place within a closed system, making them easier to monitor. However, he said, it is less clear what happens to the carbon as it travels out to the ocean.
” ‘This is a work in progress,’ he said. ‘We can make measurements that we feel very confident about in many cases, but there is still a part of the system that is a little bit fuzzy to us.’ “
More at the Globe, here.















