|Do, Young - IOWA STATE UNIVERSITY|
|Dispirito, Alan - IOWA STATE UNIVERSITY|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 9, 1997
Publication Date: N/A
Interpretive Summary: Odors coming from livestock operations raise public concern about the impact of these facilities on the quality of rural life. Odors, however, vary in intensity and duration and also depend upon the individual. Odor emissions from livestock facilities and manure storage systems represent a potential economic and environmental problem in modern agriculture. There are a large number of proposed methods to reduce odor, however, there is little basic understanding as to what causes the different odors that are detected around livestock operations. Odor consists of a complex mixture of different volatile organic compounds and we sampled the air above several different manure storage systems to determine which compounds were present and how these compounds behaved in the air. These compounds were detected in the air by collecting air samples released from manure storage systems and identified through chemical methods. There were 27 different volatile organic compounds identified that could decrease air quality in the vicinity of livestock operations. These compounds did not behave the same in the air and there were differences in the movement rates with distance from a livestock facility. This method can identify how and why changes in odor occur with different management practices and atmospheric conditions. Understanding the makeup of odors permits an evaluation of methods proposed to reduce odors in both livestock buildings and in manure storage systems.
Technical Abstract: Analytical methods for monitoring the volatile organic compound (VOC) emissions, for defining atmospheric transport coefficients, and for monitoring solution phase chemistry have been developed to define processes regulating emission of malodorous and other VOCs from a high odor swine production facility. Of the 40 organic compounds identified in liquid and outdoor air samples from the swine production facility, 27 VOCs were confirmed to contribute to decreased air quality in the vicinity of the facility. Specifically, C2 through C9 organic acids demonstrated the greatest potential for decreased air quality, since these compounds exhibited the highest transport coefficients, highest airborne concentrations, and lowest odor thresholds. Flux measurements suggested that the total rate of non-methane VOC emissions from the deep basin swine waste storage system was 500 to 5700-fold greater than established non-methane VOC fluxes from non-anthropogenic sources. The volatilization rate of malodorous and other VOCs from the stored swine waste was positively correlated with wind velocity between 0.2 and 9.4 m/sec., and a maximum concentration of VOCs present in the air was observed to occur at a wind velocity of 3.6 m/sec. Experimental Henry's law coefficients adequately predicted the transport efficiency observed for some of the VOC emissions. However, results indicated that laboratory-based extraction procedures, currently used to estimate malodor potential for swine slurry samples, provide an inaccurate representation of malodorous and other airborne VOCs actually present in the air near swine production facilities.