Your Poo Could Soon Fuel the Future
A lab run by the Energy Department is working on a way to turn some of the 34 billion gallons of wastewater produced in the U.S. into biocrude oil.
Consider this the next time you flush: New research from the Pacific Northwest National Laboratory has found a way to turn your waste into biocrude, a petroleum-like substance that can be refined and used as fuel.
The process is like what the earth does when, over millennia, it creates the crude oil we have come to rely on to power our cars and heat our homes. But hydrothermal liquefaction -- HTL, as the PNNL calls this innovative technique, developed by a team led by Rich Hallen and researchers Andy Schmidt and Justin Billing -- uses high pressure and temperature to accomplish this in minutes.
Does this mean we can look forward to poo-powered homes and vehicles?
"Not really," explains Corinne Drennan, Energy & Environment Directorate at PNNL. "If you look at the amount of petroleum we consume, the percent you could replace with poo is not significant." PNNL estimates that a single person could generate two to three gallons of biocrude per year. But humans use huge quantities of crude oil to power our modern lifestyles. That would be just a drop in the bucket of that demand. "If you crunch the numbers," says Drennan. "It is not even a percent of what we consume."
The technology, more immediately, solves a problem most of us would rather not think about. Waste is increasing, rapidly, while methods of disposing of it are aging and inadequate. According to a recent report, the volume of waste generated globally will grow by nearly 50 percent over the next ten years. We need innovative ways to recapture and use that waste. "This is a low hanging fruit," says Drennan. "It helps waste water plants with the energy consumption and tipping fees associated with managing sludges and bio solids." PNNL licensed the technology to Utah-based Genifuel Corporation, which is building a demonstration plant in Vancouver. It hopes to be the first wastewater treatment utility in North America to host hydrothermal liquefaction at one of its treatment plants.
There is no single solution to our out-of-control demand for fuel. We need to solve that from many angles. This technology is a great beginning to solving the problem of recapturing what is currently a useless form of waste. And sewage is just one form of wet waste we currently do not recycle. "It could also include manure, waste from distilleries and wineries, from paper manufacturing, and similar sources," says Drennan. "Those kinds of things, when you add them up and aggregate them, start making a real impact."
The PNNL's approach eliminates the need for drying this sort of waste, which historically made recapturing it prohibitively expensive. Instead, the material is pressurized to 3,000 pounds per square inch and fed into a reactor at about 660 degrees Fahrenheit. Heat and pressure break the cells down into biocrude and an aqueous liquid. And that can be processed using conventional petroleum refining techniques.
Even if the world's political leaders can't agree to cut carbon emissions, they have agreed to spend more money on new technologies that could achieve the same goal.
The Mission Innovation initiative will see 20 countries doubling investments in clean energy research and development over the next five years. Meanwhile, a separate effort led by Microsoft billionaire Bill Gates, Facebook founder Mark Zuckerberg and other tech CEOs called the Breakthrough Energy Coalition, will solicit private investment to fund programs.
This is an early step when it comes to finding alternative sources of energy but it is a disruptive one. Because working with the renewable resources we already know how to process to create energy can be expensive. "Agricultural waste can cost hundreds of dollars a ton," says Drennan.
And, right now, this sort of wet waste has no value. In fact, we willingly pay someone to take it away. "Currently, in the U.S., sewage sludge goes into the landfill," agrees Chan Park, associate research engineer at UC Riverside's Center for Environmental Research and Technology. "And the tipping fee to do this is 60 dollars per ton. And you have to dry the sewage sludge before sending it to the landfill. In the past, it was dried in the open air by the sun. Nowadays, sun drying is banned so people use fuel to dry it."
Finding a way to turn wet waste into energy will produce energy and save these disposal fees. HTL might even – eventually – make wet waste as valuable as other forms of biofuel. But don't start hording. Your poo is not likely to have a monetary value any time soon. "That would be hilarious," says Drennan. "But it's not likely to happen in my lifetime."
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