It is a common practice in the midwestern United States to raise swine in buildings with under-floor slurry storage systems designed to store manure for up to one year. These so-called “deep-pit” systems are a concentrated source for the emissions of ammonia (NH3), hydrogen sulfide (H2S), and odors. As part of a larger six-state research effort (U.S. Department of Agriculture-Initiative for Future Agriculture and Food Systems Project, “Aerial Pollutant Emissions from Confined Animal Buildings”), real-time NH3and H2S with incremental odor emission data were collected for two annual slurry removal events. For this study, two 1000-head deep-pit swine finishing facilities in central Iowa were monitored with one-year storage of slurry maintained in a 2.4 m-deep concrete pit (or holding tank) below the animal-occupied zone. Results show that the H2S emission, measured during four independent slurry removal events over two years, increased by an average of 61.9 times relative to the before-removal H2S emission levels. This increase persisted during the agitation process of the slurry that on average occurred over an 8-hr time period. At the conclusion of slurry agitation, the H2S emission decreased by an average of 10.4 times the before-removal emission level. NH3emission during agitation increased by an average of 4.6 times the before-removal emission level and increased by an average of 1.5 times the before-removal emission level after slurry removal was completed. Odor emission increased by a factor of 3.4 times the before-removal odor emission level and decreased after the slurry-removal event by a factor of 5.6 times the before-removal emission level. The results indicate that maintaining an adequate barn ventilation rate regardless of animal comfort demand is essential to keeping gas levels inside the barn below hazardous levels.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of the Air and Waste Management Association|
|State||Published - May 2006|
Bibliographical noteFunding Information:
Two identical deep-pit swine finishing facilities in central Iowa were monitored for this research project; this arrangement represents one of six U.S. sites monitored for a larger six-state emissions study funded by the U.S. Department of Agriculture under the Initiative for Future Agriculture and Food Systems program.12,13 Each facility monitored, as shown in Figure 1, was designed to house 1000 pigs ranging in weight between ~18 and 120 kg. Slurry was stored in a 2.4-m-deep holding concrete basin below a fully slatted concrete floor and was designed to store manure for one calendar year. Slurry removal and land application was conducted once per year in the fall (October).
The authors thank the U.S. Department of Agriculture-Initiative for Future Agriculture and Food Systems program for providing the funds necessary to complete this research project.