Iowa State University researchers have literally, and figuratively, shed new light on the odor problems arising from livestock facilities.
Jacek Koziel, an associate professor of agricultural and biosystems engineering, and his team are using black light to help neutralize the volatile components that make up objectionable odors.
Shined on surfaces coated with a thin layer of titanium dioxide, the black light initiates photo-catalytic reactions that have been found to significantly reduce several odorous chemicals that are found downwind of livestock operations.
A paper on the research project in the June 10 issue of the journal Atmosphere describes the work in the lab that has led to a test in an Iowa swine facility. The paper, Mitigation of Livestock Odors Using Black Light and a New Titanium Dioxide-Based Catalyst: Proof-of-Concept (http://www.mdpi.com/2073-4433/8/6/103) documented odor reductions from 40 to 100 percent.
Koziel has been studying livestock odor and air quality issues since joining Iowa State in 2004. About 10 years ago he tested using ultraviolet (UV) light to break down compounds that are typically found in swine and poultry odors.
“We have shown that generic UV light works very well, up to a 100 percent reduction, of these key gases,” he said.
About two years ago the Indiana Soybean Alliance funded a project to look at the use of black light, a milder version of UV light that is closer to visible light. Being less toxic, the black lights would mean fewer concerns about using it in the presence of the livestock and people working in the facilities.
Koziel said a new type of the titanium dioxide, photo-catalytic coating compensates for the lack of UV energy in the black lights. Titanium dioxide is a powdery substance that is used as a whitener in a variety of products, including toothpaste.
The coating is made by PURETi Group LLC, which is the project’s industrial partner. Researchers found that the dust that is prevalent in livestock facilities and accumulates on surfaces doesn’t affect its effectiveness in the lab.
“The pilot-scale research project, which was just finished, decreased odor emissions by 16 percent while also reducing a key ‘signature’ gas responsible for the characteristic downwind odor emissions by 22 percent,” Koziel said. “An unexpected result was a 9 percent reduction in nitrous oxide, a major greenhouse gas.”
Koziel’s team plans for the next stage of research where the black light will be directed on the ceilings and upper portions of walls, coated with titanium dioxide coating, inside livestock buildings. A similar set-up was tested by a research group in Italy, he said, and that small-scale study, which used regular UV light, showed that the pigs had greater feed efficiency.
“If that holds true and can be replicated, that’s an awesome potential finding for swine industry,” he said.
Koziel is hopeful the tests in an actual swine facility in northeast Iowa will continue to be promising. It is necessary to study the system outside the lab because conditions, such as air movement, are highly variable in livestock facilities.
— Iowa State University College of Agriculture and Life Sciences