New Equation: Pig Poop = Black Gold

In an earlier article about converting landfill gas into usable energy, I commented, “I bet we could do amazing things with hog poop.”

How about this: University of Illinois (Urbana-Champaign) researchers putting pig poop into a pressure cooker and turning it into a fairly pure crude oil. From today’s Chicago Tribune:

At the U. of I., the accelerated version of the Earth’s oil production pipeline begins with a machine that looks like a giant malt mixer, which blends the chunky raw swine manure into a thick brown slurry. The appliance sits on a table surrounded by rolls of toilet paper used to clean up any unfortunate messes, the remnants of which are splattered on the wall behind.

“We have to make sure there are no big chunks,” said [graduate student Rong] Dong, wearing a white lab coat smeared with dark brown stains.

The trick is to pressurize and heat the slurry in a precise balance to break down its molecular bonds without turning it into a gas. It takes about an hour. Best of all, the byproducts of the process are few. No, wait–the very best part is that it doesn’t smell like manure anymore.

Along the way the product is stripped of its telltale scent–it smells like wet coffee grounds–and is only slightly less pure than the natural stuff, [Professor Yuanhui] Zhang said. The only byproducts are a small puff of carbon dioxide, a few dribbles of water and a tiny bit of dirt.

Zhang’s group has also found that the sludge contains three times the energy it takes to produce it, a very good net energy gain. However, for Zhang the project has always been about eliminating the odor and potential water pollution problems associated with treating hog manure in giant waste “lagoons.”

That idea smells sweet to pork producers like Chris Borrowman, whose western Illinois farm is slated to receive an oil-producing pilot plant this fall.

Most of the manure scents that waft over to his neighbors come from a gigantic lagoon that stores enough putrid pig poop to fill 23 swimming pools. Nearly every spring, an Environmental Protection Agency inspector pays a visit in response to the neighbors’ complaints.

“When I first heard about [the technology], I was very excited,” said Borrowman. “Reducing the odor coming off of our lagoons is a huge plus for us farmers.” He speculated that neighboring grain farmers could benefit from using his cheap crude to run large diesel-guzzling equipment.

And that’s good news for Zhang, who has green dreams of pig power being produced on sustainable swine farms.

“I see each swine farmer having a little plant,” he said. “We could then raise the animal, produce the feed and process the waste locally. And then in the end, we can have a useful product. That would be a perfect world.”

This kind of sustainability doesn’t have to stop at hog farms. According to Changing World Technologies–which has a biorefinery in Carthage, MO, that processes poultry offal–the six billion tons of agricultural waste generated in the U.S. each year could produce four billion barrels of oil. What’s more, their Thermal Conversion Process (TCP) can produce other fuels and fertilizers, too. Watch for solid wastes and municipal sewage sludge to become hot commodities soon, in a city near you.