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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Nutrition, Growth and Physiology » Research » Publications at this Location » Publication #313891
Title: Volatile organic compound (VOC) emissions from beef feedlot pen surface as affected by within pen location, moisture, and temperature

Author
item Woodbury, Bryan
item Gilley, John
item PARKER, DAVID - West Texas A & M University
item MARX, DAVID - University Of Nebraska
item Eigenberg, Roger

Submitted to: Waste to Worth Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/3/2015
Publication Date: 3/1/2015
Citation: Woodbury, B.L., Gilley, J.E., Parker, D.B., Marx, D.B., Eigenberg, R.A. 2015. Volatile organic compound (VOC) emissions from beef feedlot pen surface as affected by within pen location, moisture, and temperature. In: Proceedings Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31 - April 3, 2015. http://articles.extension.org/pages/72871

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, and 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: A laboratory study was conducted to determine effects of pen location, moisture, and temperature on emissions of volatile organic compounds (VOC). Feedlot surface material (FSM) was obtained from pens where cattle were fed a diet containing 30% wet distillers grain plus soluble (WDGS). The FSM were collected from the bunk, drainage, and mound areas within three feedlot pens. The FSM were mixed with water to represent dry, wet, or saturated conditions and then incubated at temperatures of 5, 15, 25 and 35°C. A wind tunnel and TD GC/MS were used to quantify emissions of eight volatile fatty acids (VFA), five aromatics and two volatile sulfur compounds (VSC). Evaluation of emissions as affected by the specified environmental conditions was performed on individual compounds which were normalized using an odor activity value (OAV). When the odor compounds were normalized with respect to their activity value, many of the measured compounds contributed minimally to the overall odor activity. Approximately 10% of the OAV was contributed by three VFAs and one aromatic (4-methylphenol) compound. The VSC contributed the most with 87.3% of the total OAV. More than half of the OAV occurred at the base of the mound with the bunk and drainage contributing approximately equally to the remainder. The frequent wetting and drying cycles occurring near the base of the mound may contribute to a more diverse microbial population when compared with the chronically wet to saturated conditions existing behind the feed bunk. The addition of water significantly increased the OAV. Approximately 92% of the OAV was accounted for by wet and saturated conditions. In general, the addition of water decreased emissions of VFA and aromatics, and increased the emission of sulfides. Two possible causes were offered. First, the greater solubility of the VFA and aromatics allowed them to be retained in the solution fraction of the FSM and not be emitted. Second, the addition of water results in an anaerobic environment and reducing conditions, which are conducive to production of VSC. Temperature significantly affected OAV with over 60% of the total OAV occurring at 35°C. The 35°C temperature increased each odor compounds with the impact being the greatest for VSCs. It appears from this study, odor emissions are greatest during warm (i.e. > 25°C) wet periods and from specific location within the pen. Understanding the spatial variability of odor emission is important in the development of cost-effective management practices. Based on the results from this investigation, field-scale studies will be conducted to develop precision odor mitigation practices.