Title: Odorous VOC emissions following land application of swine manure slurry Authors
Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 4, 2012
Publication Date: February 1, 2013
Citation: Parker, D.B., Gilley, J.E., Woodbury, B.L., Kim, K., Galvin, G., Bartelt-Hunt, S.L., Li, X., Snow, D.D. 2013. Odorous VOC emissions following land application of swine manure slurry. Atmospheric Environment. 66:91-100. DOI:10.1016/j.atmosenv.2012.01.001. Interpretive Summary: A research project was conducted to assess the decrease in odorous chemical emissions following land application of swine manure. Emissions from manure applied to the soil surface were compared to emissions when manure was injected into the soil at a depth of 11 cm. Odorous chemical emission rates were measured in field plots by passing clean air over the manure in a small wind tunnel. Three chemical compounds accounted for 93 percent of the odor. Odorous chemical emissions decreased rapidly following land application of swine manure. Chemical emissions returned to background levels after four to eight hours. Injected swine manure had 80 to 95 percent lower emission rates than surface applied manure.
Technical Abstract: Swine manure is often applied to crop land as a fertilizer source. Odor emissions from land-applied swine manure may pose a possible nuisance to downwind populations if not applied with sufficient forethought. A research project was conducted to assess the time decay of odorous volatile organic compound (VOC) emissions following land application of swine manure. Three land application methods were compared: surface application, incorporation 24 hours after surface application, and injection. Emission rates were measured in field plots with a small wind tunnel and sorbent tubes. VOCs including eight volatile fatty acids, five aromatics, and two sulfur-containing compounds were quantified by gas chromatography-mass spectrometry. In most cases, a first order exponential decay model adequately described the flux versus time relationship for the 24 hour period following land application, but the model sometimes overestimated flux in the six to 24 hour range. The same model but with the time term squared adequately predicted flux over the entire 24 hour period. Three compounds (4-methylphenol, skatole, and 4-ethylphenol) accounted for 93 percent of the summed odor activity value. First order decay constants (k) for these three compounds ranged from 0.157 to 0.996 hr-1. When compared to surface application, injection of swine manure resulted in 80 to 95 percent lower flux for the most odorous aromatic compounds. These results show that VOC flux decreases rapidly following land application of swine manure, and that four to eight hours are required before the VOC flux returns to background levels.