Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 8/2/2013
Publication Date: 8/28/2013
Citation: Woodbury, B.L., Gilley, J.E., Eigenberg, R.A., Spiehs, M.J. 2013. Emission of volatile organic compounds as affected by feedlot location, moisture, and temperature. In: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). Kansas City, MO, July 21-24, 2013. Paper No. 131619684. (doi: http://dx.doi.org/10.13031/aim.20131619684). Interpretive Summary: Animal diets can modify the types and amounts of odors coming from manure. Understanding how environmental conditions impact the types and amounts of odors coming from manure will provide information to establish management practices that minimize odor emissions. This study looked at how different locations within the pens, the amount of soil moisture, and temperature alter odor types and amounts. As expected, odor emissions increased with increasing temperatures. Compounds containing sulfur accounted for most of the odors coming from manure originating from animal diets containing ethanol by-products. This was even more prominent when there was water present. The location within the pen that emitted the most emissions was near the base of the central mound. It is speculated that the wetting and drying cycles typical of that area of the pen is ideal for producing odors that are considered more offensive.
Technical Abstract: This study investigated the effects within pen location, moisture, and temperature on odor emission from manure resulting from a diet containing 30% wet distillers grain with solubles. Pen surface material was collected from three locations. Material from each pen was consolidated for each specific location. Approximately 6.0 kg of pen material was mixed with water to represent dry, wet, and saturated conditions. The pen material was packed into pans and incubated at a specific temperature for four days. All compounds except indole had greater emissions at 35°C than at lower temperatures. The greatest volatile fatty acid (VFA) and aromatic emissions occurred under dry conditions while wet and saturated conditions produced greater sulfide emissions. Generally, VFAs and aromatics are more soluble than sulfide compounds; therefore, when water was present, these compounds remained in the solution. Sulfide contributed 87.3% of the total odor activity value (OAV) when averaged across all treatments. Wet conditions at the bunk and drainage area may consistently have redox potentials not favorable for dimethyl disulfide and dimethyl trisulfide production. Wetting and dry cycles typical at the mound may have redox potentials during wet periods favorable for sulfide production. During dry periods redox potential may be favorable for VFA and aromatic production. This may explain why the mound accounted for over half of the OAV when compared with other locations. Sulfide contribution to the OAV is further illustrated by examining each within pen location, moisture content and temperature. Sulfide emissions dominated (i.e., > 75%) of the other compounds with the exception of the dry condition where the VFA, aromatic, and sulfide contribution was more evenly distributed. Feedlot location, moisture, and temperature may affect emission of VOC.