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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #238936
Title: Odor Mitigation with Tree Buffers: Swine Production Case Study

Author
item Trabue, Steven - Steve
item Sauer, Thomas
item Pfeiffer, Richard
item Hernandez Ramirez, Guillermo
item TYNDALL, JOHN - Iowa State University

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/2/2009
Publication Date: 9/30/2009
Citation: Trabue, S.L., Sauer, T.J., Pfeiffer, R.L., Hernandez Ramirez, G., Tyndall, J. 2009. Odor Mitigation with Tree Buffers: Swine Production Case Study. In: Proceedings of the 3rd International Congress on Biotechniques for Air Pollution Control, September 28-30, 2009, Delft, Netherlands. p. 296-299.

Interpretive Summary: Tree buffers are a potential low cost sustainable odor mitigation strategy used in animal production. However, there is little to no data on their effectiveness. Odor is thought to be carried from a facility to the surrounding community either through gas phase or odorants are absorbed onto particles for transport. This study was designed to monitor how natural buffers affect both odors transported as gases and on particles. In this study, both the particle and odorous compound concentrations were monitored before and after a tree buffer at a swine facility. Wind tunnel experiments were used to determine the effect tree buffers had on wind flow patterns within the facility. The wind tunnel experiments showed that both buildings and trees slowed the wind speeds and created turbulence (mixing) for potentially enhancing trapping of odorous material. For particulates, tree buffers reduced concentrations by 44% and tree buffers were especially effective at trapping the larger size fraction. The buffer removed volatile fatty acids (VFAs) in the air stream by over 50%, but they were not as effective at removing aromatic compounds (i.e., p-cresol). These results show that tree buffers removed VFAs more effectively than aromatic compounds. Odorants sorbed to both particulate filters and plant material also support this finding in that VFA were significantly higher than odorous aromatic compounds. Plant material taken from trees in the buffer showed significantly higher loadings of odorous VFAs, phenolic, and indole compounds for samples taken from 8 feet compared to samples taken from either 2 or 4 feet. This indicates that as the natural buffer matures the effectiveness for lowering odor potentially increases. The information presented in this paper is intended to be used by air quality specialists, engineers, animal scientists, and regulatory officials for development of odor mitigation strategies.

Technical Abstract: Tree buffers are a potential low cost sustainable odor mitigation strategy, but there is little to no data on their effectiveness. Odor transport is thought to occur one of two ways either directly through vapor phase transport or indirectly through sorption onto particles. Consequently, monitoring how natural buffers affect both vapor phase and particle phase transport is needed to evaluate their effectiveness. In this study, both the particle and odorous compound concentrations were monitored within (before) a tree buffer and outside (beyond) a buffer at a swine facility. Wind tunnel experiments were used to determine the effect buffers had on wind flow patterns within the facility. Particle concentrations were measured with optical particle counters (OPC) and odorous compound concentrations were measured using sorbent tubes with thermal desorption (TDS) GC-MS analysis. Both particle filters and plant material from tree buffers were analyzed for sorption of odorous compounds with TDS-GC-MS analysis. The wind tunnel experiments indicated that the effect of both buildings and trees on wind velocity and turbulence would potentially enhance trapping of odorous material by slowing wind velocity and increasing mixing near trees. For particulates, tree buffers reduced concentrations by 44% when winds came from the south (main buffer ran east-west on the north side of the facility). Most particles were classified in the smaller size fraction (0.30-0.49 um); however, the tree buffers removed the larger size particles more effectively than smaller size fraction. The buffer removed volatile fatty acids (VFAs) in the air stream by over 50% in both the August and September samplings. The more odorous compounds represented by aromatic compounds (i.e., p-cresol) were not as easily removed with the August sampling showing little to no difference in terms of concentrations of these compounds and September sampling showing reduced levels of aromatic compounds. There results show that the buffer removed VFAs more effectively than aromatic compounds. Odorants sorbed to both particulate filters and plant material also support this finding in that VFA were significantly higher than odorous aromatic compounds. Plant material taken from trees in the buffer showed significantly higher loadings of odorous VFAs, phenolic, and indole compounds for samples taken from 8 feet compared to samples taken from either 2 or 4 feet. This indicates that as the natural buffer matures their effectiveness for lowering odor potentially increases.