Julia
Reichelstein.

The cleanest version of carbon removal is also the least glamorous. There are no fans of fungi, no vats of algae, no shimmering direct-air machines humming in the desert. Instead there is a well, a pump, and a slurry of treated sewage and farm waste going down a hole 5,000 feet into the earth. Julia Reichelstein runs the company doing it, and she would like you to know the waste never comes back up.

Vaulted Deep, the company she co-founded and leads as CEO, sits in Houston and operates on a deceptively simple bet: the same deep-injection plumbing the oil and gas industry built to pull carbon out of the ground works just as well in reverse. Take carbon-rich organic waste - biosolids, manures, paper mill sludge - that would otherwise rot in a landfill or get sprayed on a field, and instead send it down into porous rock where it stays put. No decomposition. No methane. No PFAS leaching into someone's drinking water. The carbon that plants pulled from the sky goes back into geology, where it sat for millions of years before anyone dug it up.

The line she uses to describe the whole enterprise is tighter than any pitch deck: "We believe this is where waste ends and carbon removal begins." It is a two-sided business, and that is the trick. Vaulted gets paid to take the waste away, and it gets paid again when companies like Microsoft and Google buy the carbon removal credits that result. Most carbon removal startups have one revenue line and a prayer. Reichelstein has two.

The farmer with no rain

Reichelstein did not arrive here through a chemistry lab. She is a Stanford economist by training, with a B.A. in economics and an MBA from the Graduate School of Business, finished in 2020. The earlier chapters are stranger. She spent close to five years living in Kenya and working across East Africa and Peru on international development, eventually building a fintech startup that used alternative data to credit-score people the banks had written off as unbankable.

The turn came in a field. Working with smallholder farmers on parametric crop insurance during a seven-year drought, she pitched a financial product to a farmer who cut her off with the only fact that mattered: "That's nice, Julia, but there's no rain." It is the kind of sentence that reorganizes a career. She came away convinced that climate change is the largest single driver of global poverty, and that no amount of clever financial engineering matters if the weather has already broken.

So in 2020 she joined Piva Capital, a deep-tech and climate venture fund that has since grown to roughly half a billion dollars, and started watching carbon removal up close. She loved investing. She left anyway. The decision, by her own account, was less a spreadsheet exercise than a gut verdict - building something in carbon removal during the industry's explosive early growth simply felt, as she put it, "right in the soul."

A cold email and an inheritance

The co-founder she needed turned up almost by accident. In 2021 she reached out to Omar Abou-Sayed for advice on something unrelated, and realized mid-conversation that the waste-management business he was running, Advantek, was sitting on a climate solution hiding in plain sight. The core slurry-injection technology had been invented by Abou-Sayed's father in the 1980s - oil-patch engineering, repurposed. They spun Vaulted Deep out of Advantek in 2023. An inherited 1980s invention became a climate weapon.

Investors noticed the intensity. Matt Eggers, managing director at Prelude Ventures, which led Vaulted's Series A, summed her up without padding: "Julia's got a huge vision. She's maniacally focused." The focus has a slogan attached - "laser-focused on getting tons in the ground this decade" - and it is not marketing. The whole industry, by her math, needs to scale up 200,000 times in under thirty years. That is not a typo, and she repeats the figure deliberately, because the size of the gap is the entire point.

The XPRIZE, and the receipts

In 2024 the demonstrations turned into hardware on the board. Vaulted Deep won the $8 million XPRIZE Carbon Removal, the marquee prize in the field, after removing close to 10,000 tonnes of carbon during the competition - roughly ten times the benchmark required. It signed one of the largest carbon removal agreements anyone has inked, 4.9 million metric tons with Microsoft, plus deals with Google and Frontier Climate. Inc. named it 2025's Best Startup on a Mission. The company has raised north of $40 million in equity and projected 175% year-over-year revenue growth into eight figures for 2025.

What keeps the story from being a pure climate fairytale is that the benefit lands locally, too. At its Kansas site, Vaulted diverted 60,000 tonnes of waste, put more than $5 million into the local economy, and created 18 full-time jobs - all inside 18 months. The pitch to a small town is not abstract atmospheric chemistry. It is fewer odors, cleaner groundwater, and a payroll.

Where it goes next

Reichelstein's ambition runs past the U.S. map. In emerging markets - she names Nairobi specifically, the city she once lived near - more than 90% of human waste is dumped illegally into rivers, a public-health catastrophe braided into a climate one. The same well that stores carbon credits for a Seattle software giant could, in her telling, fix a sanitation crisis for a Kenyan capital. She is candid that the carbon removal industry is still raw - "the CDR industry infrastructure is in its infancy," she says, and "not all carbon removal is regulated, which is a fairly large issue for the space." She is also, by temperament, an optimist about the people in it: "Personally, I love the sheer amount of creativity I've seen from our peers in the space."

Responsible scaling, in her words, means "creating infrastructure that delivers real benefits for communities while maintaining safety, environmental protection, and sustainability." It is a careful sentence for a job that mostly involves sending the unwanted parts of modern life a mile underground and never seeing them again.