Take on a podcast episode from The Carbon Curve, originally published Wed, 05 Au. Listen: https://carboncurve.substack.com/p/carbon-removal-that-utilities-actually

TL;DR

  • CREW Carbon doses calcium carbonate into wastewater bioreactors, converting microbe-generated CO2 into stable bicarbonate — durable removal inside a closed, metered system.
  • Just signed a Microsoft offtake for up to 23,602 durable removal units; total book now >$40M with JPMorgan, Google, Autodesk, Stripe/Frontier.
  • Pitch to utilities is capex deferral + easier nitrogen/phosphorus compliance — CDR revenue is upside, not the core sell. Useful framing.
  • measurement, reporting, and verification (MRV) story leans on the closed reactor: mass-balance and effluent chemistry, not open-ocean modeling. Materially stronger than marine ocean alkalinity enhancement (OAE) on measurement.
  • Regulated-utility sales cycles are the real bottleneck, not chemistry. Worth taking seriously.

The Carbon Curve’s Na’im Merchant hosts Joachim Katchinoff, CEO of CREW Carbon, on turning municipal wastewater treatment plants into alkalinity-enhancement sites. The episode was taped before CREW’s Microsoft deal dropped, so the show notes carry the news; the conversation itself is about mechanism, MRV, and how you actually sell CDR into a regulated utility.

The core move: wastewater bioreactors are already CO2 factories — microbes digesting organic load produce dissolved CO2 that mostly outgasses. Dose calcium carbonate in, and that CO2 converts to bicarbonate, which leaves the plant in the effluent and ends up ocean-durable on ~10,000-year timescales. The MRV pitch is the interesting part for practitioners tired of marine ocean alkalinity enhancement modeling debates: this is a closed system with known inflows, known outflows, and measurable alkalinity deltas. You’re not back-solving what happened in a plume. Katchinoff leans hard on this — it’s the reason buyers like Frontier signed early, and it’s the credible answer to “why should this credit be worth more than open-ocean OAE.”

The commercial insight worth stealing: CREW isn’t selling CDR to utilities. They’re selling nitrogen/phosphorus removal and capital deferral — many plants face expensive upgrades to meet tightening nutrient limits, and alkalinity dosing helps the biology hit those limits more cheaply. Carbon removal is the third revenue leg that makes the unit economics work. That’s the template a lot of durable CDR pathways need: find the industrial co-benefit that gets you in the door of a risk-averse operator, and let the credit revenue subsidize deployment. Katchinoff is candid that regulated-utility procurement is slow, and scaling means winning one plant operator at a time.

For CDR context: this sits in the alkalinity-enhancement family alongside Planetary, Gigablue, and land-based enhanced weathering plays like Lithos and Mati, but the closed-system MRV argument genuinely differentiates it. The Microsoft offtake — 23,602 tons — puts CREW in the same tier of durable buyers as the Occidental and Stockholm Exergi deals, scaled appropriately for a Series A company. The buyer roster (Frontier, JPMorgan, Google, Autodesk, Microsoft) is doing the diligence work for you: if you’re skeptical, the interesting question isn’t whether the chemistry works but whether wastewater plant count and dosing rates can get this to megaton scale.

Worth an hour if you’re working on MRV design for aqueous CDR pathways, thinking about industrial co-benefit business models, or evaluating alkalinity enhancement approaches against each other.