Science: Using light to shrink livestock stink

Sometimes, science requires great sacrifices. For the sake of progress, researchers throughout history have put their health and safety at risk in the course of making new discoveries.

Other research projects may not be so dangerous — some are more on the gross side.

Researchers at Iowa State University had to put their noses to the test in a project intended to neutralize the odor given off by livestock operations using, of all things, light.

For over a decade, university professor Jacek Koziel and his team have been experimenting with using ultraviolet (UV) light to neutralize the volatile components that make, shall we say, unpleasant odors in and around poultry and swine operations. These odors can be carried by wind into surrounding communities.

“We have shown that generic UV light works very well, up to a 100% reduction of those key gases,” Koziel said.

The latest research conducted by the team involves shining UV light from a black light onto surfaces thinly coated with a new type of titanium dioxide. The light causes a photocatalytic reaction — which means the light acts as a catalyst for a chemical reaction — that has been found to significantly reduce odorous chemicals.

In its published paper, the team says that odors went from 40% to 100% reduced.

Jacek Koziel, left, and Devin Maurer analyze odor samples from a swine farm. (Courtesy of Iowa State University)

Black light is a mild form of UV light, and is closer to being visible. It’s not as harmful as regular UV light, which can damage the eyes and cause skin cancer, so it can be used more safely around people and animals. Even though the light is mild, its reaction with the titanium dioxide catalyst makes up the difference.

Titanium dioxide is used as a whitener in products like toothpaste. Researchers found in the lab that even when the catalyst-coated surfaces were also coated in dust, the reaction still worked.

“The pilot-scale research project, which was just finished, decreased odor emissions by 16% while also reducing a key ‘signature’ gas responsible for the characteristic downwind odor emissions by 22%,” said Koziel.

There’s a bonus, too.

“An unexpected result was a 9% reduction in nitrous oxide, a major greenhouse gas,” he said.

What’s next? First, the team is taking their studies out of the lab, to a swine facility in Iowa, to look for real-world results.

The team also plans to investigate the effects of coating ceilings and upper portions of walls with titanium dioxide, and directing the black light towards it. A similar arrangement in Italy has even led to greater feed efficiency for pigs in the barn.

“If that holds true and can be replicated, that’s an awesome potential finding for the swine industry,” Koziel said.

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