Iowa State University researchers have shed new light -- literally and figuratively -- on odor problems arising from livestock facilities.
Jacek Koziel, an associate professor of agricultural and biosystems engineering, and his team at Iowa State 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 shown to significantly reduce several odorous chemicals that are found downwind of livestock operations, according to the university.
A paper on the research project in the June 10 issue of the journal Atmosphere describes the work in the lab that led to a test in an Iowa swine facility. The paper, "Mitigation of Livestock Odors Using Black Light & a New Titanium Dioxide-Based Catalyst: Proof-of-Concept" (http://www.mdpi.com/2073-4433/8/6/103), documented odor reductions of 40-100%.
Koziel has been studying livestock odor and air quality issues since joining Iowa State in 2004. About 10 years ago, he tested the use of 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% 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. Since they are less toxic, the black lights would bring fewer concerns when used in the presence of 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, which is prevalent in livestock facilities and accumulates on surfaces, doesn’t change its effectiveness in the lab.
“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%,” Koziel said. “An unexpected result was a 9% reduction in nitrous oxide, a major greenhouse gas.”
Koziel’s team is planning for the next stage of research in which the black light will be directed on the ceilings and upper portions of walls, covered with titanium dioxide coating, inside livestock buildings. A similar setup 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 the swine industry,” he said.
Koziel is hopeful that the tests in an actual swine facility in northeastern 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.