From Waste To Energy - The Untapped Power Of Poop

When we talk about renewable energy, solar, wind, and hydro usually dominate the conversation. But what if I told you there's another abundant, carbon-neutral resource we're literally flushing away every single day? I'm talking about human waste—an overlooked energy source that could revolutionize how we think about waste management, energy production, and environmental sustainability.

The Scale of the Problem

Let's face it: there are three unavoidable things in life—death, taxes, and bathroom breaks. Every person produces about a pound of waste per day. Multiply that by several billion people, 365 days a year, and you start to understand the magnitude of what we're dealing with. In the United States alone, we produce an estimated 5 to 13 million dry tons of sewage sludge annually. Add the water content, and that's billions of gallons of waste every single year.

Most of us never think about what happens after we flush. The journey begins at the wastewater treatment plant, where solids are separated from water. From there, those biosolids meet one of three fates: incineration, landfilling, or application to agricultural fields. About 50% of US biosolids end up on agricultural land, used to grow animal feed for livestock like dairy cows.

The Hidden Costs of Current Waste Management

Each of these disposal methods comes with serious drawbacks. Incineration releases all that stored energy and material into the atmosphere. Landfilling generates methane—a greenhouse gas 25 times more potent than CO2. And agricultural application? It can introduce contaminants like microplastics, pharmaceuticals, and forever chemicals (PFAS) back into our food chain.

Multiple dairy farms in Maine have already shut down production due to high PFAS levels in their milk, resulting in devastating financial losses and damaged public trust. Meanwhile, wastewater treatment plants consume more than 30 terawatt-hours of electricity annually—about $2 billion in costs—representing 25-40% of their operating budgets.

 An Old Technology Makes a Comeback

The solution to this problem isn't new at all. Hydrothermal carbonization (HTC), also known as subcritical water carbonization, was first discovered in 1913 by German Nobel Prize chemist Dr. Bergius. However, the tumultuous 20th century in Germany—including two world wars and national division—meant this technology wasn't seriously revisited until 2006 at the Max Planck Institute.

So what exactly is HTC? Think of it as an industrial-sized pressure cooker that runs continuously. The process applies heat and pressure to waste material—10 to 50 bars of pressure at temperatures between 180-250°C. This puts water into a subcritical state where it starts to boil but the pressure prevents it from turning to steam.

According to Dan Spracklin from Somax, a company commercializing this technology, "What we're doing essentially is taking large molecules, first we chop them up, and then we pull off some oxygen atoms and some hydrogen atoms to make a more stable compound and smaller molecules. Then the last step is we recombine those molecules to make useful products."

The result? Coal. Or rather, a coal alternative. The process mimics what Earth does naturally over hundreds of millions of years—but accomplishes it in less than an hour.

Multiple Products, Multiple Benefits

The beauty of HTC isn't just in creating a coal substitute. The process generates several valuable products:

**Energy Production**: The resulting hydrochar has a fuel value similar to lignite coal and can be used in coal-fired infrastructure. Even better, the process produces a liquid byproduct rich in volatile organic compounds that can fuel anaerobic digestion to create biogas. Some studies suggest that plants using HTC can increase biogas production by up to 5% while dramatically reducing energy costs.

**Construction Materials**: The solid products from HTC can replace sand in concrete. At just 10% replacement rates, you could offset all emissions from cement production. Engineers in Australia tested bricks made with 25% biosolids and found they reduced energy use by nearly half during the firing process.

**Carbon Sequestration**: Incorporating biosolids into construction materials locks away carbon for thousands of years. You can break it, reuse it, or dispose of it—the CO2 isn't coming back out.

**Clean Fertilizer**: HTC can create carbon-neutral fertilizer while eliminating PFAS contamination. The high temperatures and pressure break apart those notoriously strong carbon-fluorine bonds, destroying these "forever chemicals" in the process.

**Water Filtration**: The carbon product from HTC can be activated to create filtration material for drinking water systems.

Real-World Impact

The economics are compelling. HTC treatment costs about $600-700 per dry ton of sewage sludge, compared to $660-1,000 for current treatment methods. But the savings go beyond direct costs.

In Phoenixville, Pennsylvania, Somax is building North America's first commercial HTC plant. According to Spracklin, "We're able to produce 153% of the energy demand of that treatment plant. So it goes from being the largest consumer of energy in that municipality to a net energy producer." That extra energy goes back to the grid to power city hall, street lights, police and fire stations.

 The Challenges Ahead

If this technology is so promising, why aren't we seeing it everywhere? The answer is complex. HTC hasn't attracted the massive investment that solar, oil, or gas have received. Many sustainability experts aren't even aware the technology exists because it's only recently emerged from academic research into real-world application.

The biggest challenge may be regulatory. Dealing with human waste means navigating extensive red tape designed to protect public health. In Pennsylvania, despite having US Department of Energy approval, it took Somax three years just to get the permit to try the process at a wastewater treatment plant.

 The Bottom Line

HTC represents a genuine two-birds-one-stone solution. We have to deal with our waste anyway—why not extract value from it while reducing environmental harm and generating clean energy? The source material is constantly available, unlike solar or wind. Treatment plants could transform from energy consumers into energy producers while creating valuable products and eliminating harmful contaminants.

As Dan Spracklin puts it, HTC is bringing this technology "out into the world to make people aware of it." The process can carbonize everything from sewage sludge to t-shirts to flowers. One particularly surprising discovery: hydrochar made from raw sludge works exceptionally well as activated carbon for filtering pollutants.

The path forward requires bridging the gap between theoretical potential and full-scale application. With growing awareness, regulatory approvals, and successful demonstration projects like Phoenixville, we may finally be ready to stop flushing away a valuable resource.

The decision seems clear: it's time to get serious about the literal power of crap. Because when it comes to renewable energy solutions, this one is always number one—even if the source material is number two.