Location: Livestock Nutrient Management ResearchTitle: Farm-scale testing of soybean peroxidase and calcium peroxide for surficial swine manure treatment and mitigation of odorous VOCs, ammonia and hydrogen sulfide Author
Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2017
Publication Date: 8/3/2017
Citation: Maurer, D., Bruning, K., Koziel, J., Parker, D.B. 2017. Farm-scale testing of soybean peroxidase and calcium peroxide for surficial swine manure treatment and mitigation of odorous VOCs, ammonia and hydrogen sulfide. Atmospheric Environment. 166:467-478.doi:10.1016/j.atmosevn.2017.07.048. Interpretive Summary: Ground soybean hulls reduce swine manure nuisance odors. Ground soybean hulls contain a naturally occurring enzyme called soybean peroxidase. The ground hulls, when mixed with calcium peroxide, have been shown in earlier laboratory experiments to reduce odors from swine manure. A farm-scale experiment was conducted by scientists from Iowa State University and ARS (Bushland, Texas) to evaluate the surface application of ground soybean hulls to reduce odors from swine manure under field conditions. The ground soybean hulls and calcium peroxide were applied to the surface of the swine manure in the shallow pit of a swine barn. Air emissions were monitored for 42 days. The chemicals most responsible for swine odor were reduced by 36 to 80 percent. The total treatment cost, including materials and labor, was 2 dollars and 62 cents per marketed pig. These results are of interest to swine producers and people that advise swine producers as a means of reducing odors.
Technical Abstract: The swine industry, regulatory agencies, and the public are interested in farm-tested methods for controlling gaseous emissions from swine barns. In earlier lab- and pilot-scale studies, a renewable catalyst consisting of soybean peroxidase (SBP) mixed with calcium peroxide was found to be effective in mitigating gaseous emissions from swine manure. Thus, a farm-scale experiment was conducted at the university’s 178-pig, shallow-pit, mechanically-ventilated swine barn to evaluate SBP as a surficial manure pit additive under field conditions. The SBP was applied once at the beginning of the 42-day experiment at an application rate of 2.28 kg per square meter with 4.2 percent calcium peroxide added by weight. Gas samples were collected from the primary barn exhaust fans. As compared to the control, significant reductions in gaseous emissions were observed for ammonia (21.7 percent), hydrogen sulfide (79.7 percent), n-butyric acid (37.2 percent), valeric acid (47.7 percent), isovaleric acid (39.3 percent), indole (31.2 percent), and skatole (43.5 percent). Emissions of dimethyl disulfide/methanethiol increased by 30.6 percent. Emissions of p-cresol were reduced by 14.4 percent but were not statistically significant. There were no significant changes to the greenhouse gas emissions of methane, carbon dioxide and nitrous oxide. The total treatment cost was 2 dollars and 62 cents per marketed pig, equivalent to 1.5 percent of the pig market price.