Enhanced dispersion and removal of ammonia emitted from a poultry house with a vegetative environmental buffer

Authors: Ro, Kyoung; LI, HONG - University Of Delaware; Hapeman, Cathleen; HARPER, LOWRY - Harper Consulting Co; FLESCH, THOMAS - University Of Alberta; DOWNEY, PETER - University Of Maryland; MCCONNELL, LAURA - University Of Maryland; TORRENTS, ALBA - University Of Maryland; YAO, QI - University Of Maryland

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2018
Publication Date: 3/22/2018
Citation: Ro, K.S., Li, H., Hapeman, C.J., Harper, L.A., Flesch, T.K., Downey, P.M., Mcconnell, L., Torrents, A., Yao, Q. 2018. Enhanced dispersion and removal of ammonia emitted from a poultry house with a vegetative environmental buffer. Agriculture. https://doi.org/10.3390/agriculture8040046.
DOI: https://doi.org/10.3390/agriculture8040046

Interpretive Summary: Vegetative environmental buffers (VEBs), composed of tolerant trees, shrubs, and tall grasses, are frequently installed near the exhaust fans of poultry houses to control and reduce the off-site transport of potential pollutants, such as ammonia. The VEBs also enhance the aesthetics of these animal feeding operations (AFOs) facilities and the overall landscape, positively increase the public perception of AFOs, and provide a tangible demonstration of producer environmental stewardship. However, the effectiveness of VEBs in controlling the poultry house ammonia emissions has not been quantitated. Therefore, we conducted a series of experiments to determine the effect of dispersion and removal of ammonia from a simulated gas stream released just outside a small poultry house which was surrounded by a mature VEB. The measured downwind concentrations were compared to the theoretical downwind concentrations which were calculated from an additional series of experiments where no VEB was present. We found that the VEB enhanced dispersion, resulting in a 63% reduction of the ammonia concentration in emitted gas downwind from the VEB when compared with the theoretical concentrations. In addition to dispersion, the ammonia concentration was reduced by 22% due to sorption to the trees. These results clearly demonstrated that VEBs are effective both in dispersing and removing ammonia emitted from the poultry houses. This information will be used by United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS) in developing VEB standards to address poultry house emissions.

Technical Abstract: Vegetative environmental buffers (VEBs), composed of tolerant trees, shrubs, and tall grasses, can be used to control and reduce the transport of ammonia (NH3) emissions from animal feeding operations (AFOs). However, the effectiveness of VEBs has not been quantitated. Here, we measure the dispersion and removal of NH3 in simulated emissions from a small broiler house equipped with a VEB. The dispersion enhancement due to the VEB was estimated by comparing the measured downwind concentration of the co-released tracer gas, methane (CH4), to the theoretical CH4 concentrations at the same distance downwind without the VEB. The accuracy of the theoretical downwind concentrations calculated using the forward Lagrangian stochastic (fLS) technique was 95%, which was validated by comparing measured and calculated CH4 concentrations in a separate experiment without the VEB. The VEB enhanced the dispersion of CH4 and reduced the downwind concentration by 63% of the theoretical concentration. In addition to dispersion, the VEB removed another 22% of the NH3, resulting in a net 49% decrease of the theoretical downwind concentration. These results clearly demonstrated that the VEB was effective both in dispersing and removing NH3 emitted from the broiler house. This information will be used by USDA-NRCS in developing VEB standards to address poultry house emissions.