Swine Odor Remediation

Limiting odors from swine-feeding operations is one of the most difficult and problematic issues facing agricultural scientists. A team led by swine specialist Kephart identified eight Pennsylvania swine enterprises that were known to have conflicts with neighbors over odor. “For each, we picked one of three odor-remediation methods - dust filtration on exhaust fans, biofiltration of exhausted air, and biofiltration of air and gas coming from stored manure in a concrete tank or lagoon,” he says. “Then we asked neighbors near each farm to evaluate the odors between the hours of 6:00 P.M. and midnight.”

Kephart chose odor-control methods that were inexpensive and easy to install, such as covering manure lagoons with a foot-deep layer of chopped straw and directing air from exhaust fans through wood chips and compost. These simple, economical biofilters were surprisingly effective, with neighbors reporting significant reductions in odor. “But we didn’t just ask neighbors about odor,” says Kephart. “We surveyed them on their feelings about livestock production and tried to relate their answers to odor scores. As you might expect, we discovered that people who lived downwind of the swine facilities had higher odor scores.

“But we learned other things you wouldn’t expect,” Kephart adds. “For instance, if the neighbors knew the producers personally, their odor scores were lower overall. And if neighbors perceived the farm as attractive, they had lower odor scores. Personal factors that had nothing to do with science or physics have a lot to do with how neighbors perceive odors.”

The College’s Contribution
The college’s efforts in the arena of agricultural emissions are an example of how Penn State brings science to issues of critical importance to Pennsylvania agriculture and citizens, points out Bruce McPheron, associate dean for research and graduate education. “The change in demographic patterns in traditionally rural areas of the Commonwealth brings agricultural production and residential life into close proximity,” he says. “This naturally creates tensions, which must be addressed by well-informed communication. Our role is to examine the science behind emissions-related issues and discover means to reduce or remove the problems. We can educate policy makers, producers, and citizens to help them understand and implement alternatives as they are identified. The diversity of research programs under way in the college illustrates the wide-ranging need for answers. We have not yet solved the problems, but we recognize the serious nature of the issues and are moving aggressively to discover and implement solutions that will serve all aspects of Pennsylvania’s needs.”

The college’s research has a fairly rapid application in the field, according to Wheeler, who notes that it is not basic science so much as it is applied science and engineering. “We have a great breadth of multidisciplinary research in measuring, controlling, and mitigating agricultural emissions across many commodities,” she says. “We have people from horticulture, dairy and animal science, poultry science, agricultural economics, crop and soil science, plant pathology, agricultural and biological engineering, cooperative extension, and the Penn State Institutes of the Environment working in this area, and we are working with researchers in other states. We are not just working on problems peculiar to Pennsylvania.”

Faculty referenced in this article are Ken Kephart, professor of animal science; Bruce McPheron, associate dean for research and graduate education; Paul Patterson, associate professor of poultry science; Gabrielle Varga, distinguished professor of animal science; and Eileen Wheeler, associate professor of agricultural engineering.