Biofilters like this one filter air from a concentrated animal feeding operation through wood chips reducing compounds that create odor in swine operations.
Biofilters like this one filter air from a concentrated animal feeding operation through wood chips reducing compounds that create odor in swine operations.

Teng Teeh Lim, University of Missouri Extension researcher, wants to give large, concentrated animal operations an economical way to reduce odors. Lim works as part of University of Missouri Extension’s Commercial Agriculture Program and in ag systems management for the College of Agriculture, Food and Natural Resources to improve air quality and waste management in large animal production.

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 issues. “Measurement of emissions in the field can be very costly, very tedious to conduct and requires hard work and equipment maintenance for constantly-changing emissions from such facilities,” Lim said.

One solution lies in Lim’s research on biofilters containing materials like wood chips that support microbial colonies – filter out and break down compounds that create those odors.

“Biofilters create an environment for microbes to thrive by using the exhaust stream – the odors, the dust and gases – as nutrients to supply their own population,” said Lim.

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 many fine details – material selection and composition, filter size, positioning, moisture control – and putting them together becomes an art, especially to do affordably,” 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 odors 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.

Two sides of a coin

Concentrated animal feeding operations (CAFOs) can rejuvenate struggling rural economies with much needed jobs and tax revenue. A 2011 study funded by University of Missouri’s Commercial Agriculture Program found that the economic benefit in northwest Missouri totaled about $1.1 billion each year for the region.

Yet, in 2010, a jury awarded one northwest Missouri group of landowners $11 million in a lawsuit against one CAFO, when they ruled that the odors from the facility harmed their quality of life. In spring 2011, the Missouri State General Assembly passed a bill that would limit the monetary award for so-called “nuisance lawsuits” to the value of a person’s property.

Talk of further federal regulation also makes it prudent for CAFOs to be proactive in managing their emissions to improve air quality. The Environmental Protection Agency is conducting similar studies to understand overall emissions from farm facilities with a distant eye on future rules.

Lim said university research on emission models parallels EPA’s efforts, but avoids the influence of regulations and politics, and university emission models can be compared with EPA models when the agency considers regulatory changes.

While there’s still some way to go in perfecting biofilters and bringing the price down, investing a few thousand to a few hundred thousand dollars to implement a biofilter system in an operation pales in comparison to what lawsuits can cost a company.

“When a producer is more proactive it gives the impression that he’s being responsible and a good neighbor,” Lim said. “We’ve already learned so much but we want to further carry on and refine biofilters to be more specific and drive down the cost and maintenance so more people can use this technology.”

The computer model will be available to use online later this fall.

Source: University of Missouri