Some call it the smell of money, but Teng Teeh Lim thinks that smell does not have to be so bad.
The University of Missouri Extension researcher wants to give large, concentrated animal operations an economical way to lessen those troubling smells.
Lim recently received a $50,000 Mizzou Advantage grant to develop a computer model that allows large producers to use the size and other simple information about their swine or dairy farm to give them a better idea of the amount of emissions and what they can do to address odor or emission issues.
"Measurement of emissions in the field can be very costly, very tedious to conduct and requires such hard work, set up and equipment maintenance for forever changing pollutants and exhaust from such facilities," Lim said. "A lot of the information we collect in the field aren't readily available from average producers, so it becomes a give-and-take thing to create a model that uses only a few key variables that most people can understand and use while only losing some precision."
Putting microbes to work
One solution lies in Lim's research on biofilters.
Biofilters - materials like wood chips that support microbial colonies - filter out and break down compounds that create those pungent odors.
"You're providing an environment for microbes to happily live in and multiply by using the exhaust stream - the odors, the dust, different gases - as nutrients to supply to their own population," said the MU Extension assistant professor.
Biofilters have existed for decades, but Lim wants to make them cheaper and more accessible to producers. Lim's biofilter work builds on years of research to improve air quality and builds on the experience of colleagues across the country.
"There are all kinds of fine details - material selection and composition, filter size, positioning, moisture control - that, when you put them together, becomes an art, especially to do inexpensively," he said.
Lim's models use on-the-ground measurements of emissions - such as dust, ammonia and hydrogen sulfides - collected during a two-year study of poultry, swine and dairy farms spearheaded by Purdue University. The hope is that in the near future a large producer can spend his money more efficiently to mitigate smell without the cost of on-the-ground emission measurement.
By attaching a correctly sized, small-scale biofilter to the ventilation system on a hog, dairy or poultry farm, up to 45 percent of the emissions can be reduced from the facility. Compounds like dust and ammonia create the strong odors in poultry farms while swine facilities emit more hydrogen sulfide in its smell, and different microbes will thrive in the same wood chips to consume whichever compounds are most prevalent.