Soybean oil could help reduce greenhouse-gas emissions when sprayed in swine finishing barns. Purdue University agricultural engineers Al Heber and Jiqin Ni studied the effect that soybean oil had on dust and odor in hog facilities.

“This project provided baseline measurements of the greenhouse-gas contributions of swine finishing barns,” Heber notes. “In addition to the baseline measurements, we now have some data on an abatement technology to reduce the carbon footprint contribution of a pound of pork.”

The Purdue study was conducted at a northern Missourifarm during a 12-month period ending in the summer. The study monitored two 1,100-head barns; one used the oil, the other served as a control unit.

The treated barn was sprayed with 5 cubic centimeters of oil per square meter of floor for one minute per day. The procedure was similar to the spray technology used to spray pesticides on crop fields.

Compared with the unsprayed barn, the oil-treated facility averaged 20 percent lower methane-emissions rate and a 19 percent average reduction in carbon dioxide emissions.
Both methane and carbon dioxide are greenhouse gases.

“The spray takes out dust, and since dust absorbs gases and carries odor, there was a scientific reason why it might remove those greenhouse gases,” Heber says. There was some odor reduction, but it wasn’t statistically significant. Dust reduction was more significant. The treated barn recorded 65 percent less particulate than the untreated barn.

However, several challenges surfaced,  including safety, as well as cleaning and application costs. “First of all, soybean oil is more expensive now than it was when we did the study,” Heber says. “In addition, some of the oil ended up on the floor, the pigs, the feeders and fans.” The producer indicated that it took an additional day of power washing to clean that barn, and that’s an extra expense.

Still, Heber is hopeful. “There are technical problems with this practice, but those may be overcome through good engineering,” he adds.

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