Microsoft signs 23,602-ton carbon removal deal with wastewater alkalinity enhancement firm Crew

Microsoft has signed a carbon removal agreement with Crew Carbon for up to 23,602 carbon removal units generated from Crew’s wastewater alkalinity enhancement (WAE) technology. The deal marks the tech giant's third carbon removal purchase since it announced earlier this year that it was adjusting the pace of its acquisitions in this space.

Crew’s proprietary process works by dosing alkaline minerals, such as calcium carbonate, into wastewater treatment plants to reduce the carbon footprint of their operations. Wastewater treatment plants produce CO2 as a byproduct, which is typically released into the atmosphere. Crew says its WAE technology converts dissolved CO2 into stable bicarbonate ions instead of allowing it to escape as gas. The inert bicarbonate is subsequently discharged into oceans, rivers, or aquifers, offering a durable and measurable removal pathway.

Rather than building new infrastructure, the company integrates its process within existing wastewater treatment plants, claiming it can take a facility from initial assessment to full deployment in about three months. That modular, low-footprint approach is designed to scale quickly across the large installed base of municipal treatment facilities.

“Microsoft’s offtake agreement with Crew supports the advancement of a novel, wastewater-based approach that is highly durable and measurable,” said Phillip Goodman, carbon removal portfolio director at Microsoft. “Crew has shown that carbon removal in the wastewater sector is implementable and scalable with high Monitoring, Reporting and Verification (MRV) certainty.”

According to Crew, its closed-system approach includes inlet and outlet monitoring, and all of its carbon removals are quantified via plant-level monitoring, tracked with downstream modeling, and verified by independent registries. This verification framework is central to the credibility of the credits, particularly as corporate buyers face increasing scrutiny over the quality of their carbon portfolios.

“This agreement with Microsoft is a major milestone for Crew, and further validates our approach to delivering high-quality, durable carbon credits while we optimize wastewater treatment performance,” said Dr. Joachim Katchinoff, CEO and co-founder of Crew.

Crew was spun out of Yale University by Dr. Joachim Katchinoff and Professor Noah Planavsky. Its first commercial project is located at the East Shore Water Pollution Abatement Facility in New Haven, Connecticut. The plant processes 40 million gallons (151.4 million liters) of wastewater a day and is set to become one of the largest carbon removal projects on the US East Coast, underscoring the potential scale of the WAE approach in a region with dense urban infrastructure.

The Microsoft deal is not Crew’s first with a data center-linked firm. In May of last year, it signed a $32.1 million offtake agreement with carbon buying consortium Frontier for 71,878 tons of carbon dioxide removal, to be delivered between 2025 and 2030. That earlier commitment helped establish Crew’s credibility in the voluntary carbon market and paved the way for larger corporate partnerships.

Microsoft has signed numerous carbon removal deals over recent years; however, it has significantly reduced its purchasing cadence in 2026, following reports earlier this year that it was adjusting the pace of its carbon removal purchases. Since then, it has inked two other carbon removal agreements: a 650,000-ton deal with Danish bioenergy carbon capture and storage firm BioCirc, and a 36,920-ton deal with enhanced rock weathering firm Alt Carbon in Darjeeling, India.

The continued—if slower—flow of deals suggests that Microsoft remains committed to its long-term carbon removal strategy, even as it recalibrates near-term volumes. For the broader carbon removal industry, the agreement reinforces the growing role of wastewater-based methods as a complement to more established approaches like direct air capture and bioenergy with carbon capture, particularly for buyers seeking high-durability credits with strong verification standards.