The World's Largest Toilet

You apparently can now be paid to do your business. Do it for the planet.

I suspect that by now most of us have heard that bovine belching is a significant contributor to global greenhouse gas emissions. Well, friends, I have bad news for you: everyone poops, and all of that waste produced contains large amounts of embedded carbon and also generates its fair share of climate-warming emissions. Microsoft is aware of this fact and is on the job. The company has entered into a contract to purchase 4.9 million metric tons of “bioslurry” from a startup called Vaulted Deep. After 4.5 billion years of success managing waste from plants and animals of all sizes, all over the world, Mother Nature now needs us to build the world’s largest toilet through which to flush raw human sewage and animal manure into the bowels of the Earth lest it tip us over the edge into an uncontrollable climate disaster. The sprawling agricultural industry needed to feed 8.1 billion humans generates so much organic waste that it can virtually sterilize large swaths of the ocean as well as polluting sources of drinking water and creating air pollution.

But this is not Queen Elizabeth I’s throne. No, Vaulted Deep is in the business of drilling Underground Injection Control (UIC) wells. I had the honor of once reviewing applications for Class I UIC well permits at the Texas Commission on Environmental Quality. One of my permittees operated a beef slaughterhouse in the Texas Panhandle. The slaughterhouse employees periodically rinsed the killing floor with high pressure washers, and the resulting goop was pushed through filters and pumped deep underground into a porous rock formation wherein it was destined to be trapped for all eternity. So, I get the gist of what Microsoft is trying to accomplish. The UIC program has been a very successful part of the Safe Drinking Water Act for decades. Injection wells are a mature and reliable technology when constructed and monitored properly. They are not, however, inexpensive or simple to operate. One challenge my slaughterhouse had was maintaining sufficient filtering and disinfection at the surface to avoid runaway bacterial growth underground. Clumps of bacteria, if allowed to propagate, can eventually clog a well to such an extent that it has to be abandoned and a replacement well drilled. Gross, right? (How much poo did Microsoft buy again?) Vaulted Deep wants to drill, baby, drill. Their hope is that carbon sequestered from the atmosphere in this way is worth so much that the process will be profitable if deployed at industrial scale across the entire country.

To reiterate, a farm or waste treatment plant near you may soon be making plans to dig an elaborate septic tank. The local geology must be suitable, meaning that the well must be routed through impermeable zones isolating the waste injection formation from sources of drinking water (aquifers) above while also preventing it from seeping downward into porous formations below. The injection formation must also be large and permeable enough to prevent the waste from causing underground pressures to rise so much that they can fracture rocks (yes, this is the same kind of “fracking” that oil companies try to achieve—but in the context of waste disposal fracking is strictly forbidden) or otherwise cause waste to migrate laterally outside of the permitted area. Wellhead pressures and pumping rates must be continuously measured to ensure compliance with permit limits that are set to guarantee safe operation. And there is, of course, a limit to the ultimate amount of waste any particular formation can hold.

Large scale animal waste injection is not a terrible idea. On the other hand, it is a cost we should be prepared to see reflected in higher prices for food and water. Proactive management of agricultural runoff and sewage is important for our own health as well as being a potential source of carbon removal credits for industry. Oh, yes, that’s why Microsoft cares about any of this after all: the sales pitch is that some of the carbon emissions attributable to the company’s growing fleet of data centers will be neutralized by the removal of biowaste. Let’s hope that we can prioritize what will inevitably turn out to be limited numbers of prime waste injection well drilling sites to offset the most important applications. I’d personally place applications such as air traffic control, pharmaceutical development, and cyberattack-resistant navigation ahead of self-driving taxis, cat video generators, and meme coin mining in the queue.