Submitted to: Air and Waste Management Annual Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/21/2005
Publication Date: 6/21/2005
Citation: Koziel, J.A., Lo, Y., Wright, D.D., Nielsen, L., Trabue, S.L., Kerr, B.J. 2005. The use of spme and multidimensional gc-ms-olfactometry system for identification of key odorants from swine manure. In: Proceedings of the Air and Waste Management Annual Conference, June 21, 2005, Minneapolis, Minnesota, p. 11. Interpretive Summary: Swine operations are sources of odor with swine manure being its primary source. Manure is a complex mixture of undigested and partially digested feed material along with intestinal endogenous secretions. Anaerobic digestion of this material by microorganisms is the primary source of odor generation. Identifying the key (dominate) compounds responsible for odor will enable researchers to focus on what compounds should be monitored and what strategies should be put in place to control odor. The objective of this study was to identify key odorants emitted from swine manure. An instrument with the capacity to separate individual compounds by gas chromatography (GC), and to identify both the odor (both its character and intensity) and compound associated with the odor was used for this purpose. Identifying an odor’s characteristics (description) and intensity was preformed with an olfactometer (O), which uses the human nose as a detector. The compounds responsible for the odors were identified using a mass spectrometer (MS) in an analytical technique known as GC-MS-O. Manure was collected from a deep pit waste storage system that was located under a swine building in Iowa. Odorants emitted from the manure were trapped onto a solid phase microextraction (SPME) device. The SPME devices then released the odorants into an instrument for GC-MS-O analysis. A total of 64 odorous compounds were identified with this procedure. The preliminary assessment of the key odorants includes hydrogen sulfide, methyl mercaptan, guethol, p-cresol, indole, and skatol. This is the first step in targeting specific compounds responsible for odor. Knowledge of these compounds will enable producers to identify dietary components that may be curtailed in order to reduce the primary source material in swine diets. Odor reduction technologies that target these specific compounds or the generation of these compounds could be developed as an alternative odor abatement strategy.
Technical Abstract: Swine operations are sources of volatile organic compounds and odor with swine manure being the primary source of odor from swine operations. Identification of specific key odorants can improve the understanding of odor generation, odor fate, and odor control approaches. In this research, solid phase microextraction (SPME) was used to sample headspace of swine manure followed by simultaneous chemical and olfactory analyses on a multidimensional GC-MS-O system. Sampling time ranged from 2 sec to 43 hrs. Manure was collected from the deep pit waste storage under the research swine building in Iowa. To date, 64 odorous compounds have been identified. The preliminary assessment of the key odorants includes hydrogen sulfide, methyl mercaptan, guethol, p-cresol, indole, and skatol. These results will allow for focusing of analytical methods on target compounds needed for monitioring odor abatement studies.