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Manure produced in Midwestern U.S. pig finishing facilities is usually stored in concrete deep-pits beneath the building before land application. Manure foaming in deep-pit barns has recently become a problem, causing a safety hazard. Since no obvious cause for this foaming was observed, compositional analysis was conducted to reveal differences between foaming and non-foaming manure samples to determine any specific components that can be correlated to foaming. Result shows that foaming manure samples have higher concentrations of solids, lipids, trace metals, and proteins than non-foaming samples. [ABSTRACT FROM AUTHOR]

The objective of this study was to measure the long-term odor emissions and corresponding concentrations and emissions of 20 odorous volatile organic compounds (VOCs). This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). Odor and odorous gas measurements at four NAEMS sites, including dairy barns in Wisconsin (WI5B) and Indiana (IN5B), a swine finisher barn in Indiana (IN3B), and swine gestation and farrowing barns in Iowa (IA4B), were conducted from November 2007 to May 2009. The odorous gas samples were collected every two weeks using sorbent tubes (samples were collected twice each season of the year, with the exception of spring 2009 when samples were collected three times) and analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MSO). In this article, we summarize the measured gas concentrations and emissions of the 20 target VOCs from each of the four sites. The average total odorous VOC concentrations for the entire sampling period were 276, 96.9, 1413 and 394 µg dsm-3 for WI5B, IN5B, IN3B, and IA4B, respectively. For the swine sites, the highest seasonal average total odorous VOC concentrations for each barn were observed during spring (1890 µg dsm-3 for IN3B and 458 µg dsm-3 for IA4B). For the dairy sites, the highest seasonal average total odorous VOC concentrations were observed in winter at WI5B (446 µg dsm-3) and in summer at IN5B (129 µg dsm-3). The average total emission rates for the 20 odorous VOCs were 290 mg h-1 AU-1 (WI5B), 36.0 mg h-1 AU-1 (IN5B), 743 mg h-1 AU-1 (IN3B), 33.9 mg h-1 AU-1 (IA4B swine gestation barns), and 91.7 mg h-1 AU-1 (IA4B swine farrowing room). The average seasonal total odorous VOC emission rates were highest during summer at WI5B (805 mg h-1 AU-1), IN5B (121 mg h-1 AU-1), and IN3B (1250 mg h-1 AU-1) and during spring at IA4B (95.8 mg h-1 AU-1). The emissions of specific VOCs varied between seasons, sites, and species. To date, this is the most comprehensive VOC measurement survey of odorous compound emission rates from commercial livestock buildings. [ABSTRACT FROM AUTHOR]

Simultaneous chemical and sensory analyses using gas chromatography-mass spectrometry-olfactometry (GC-MS-O) for air samples collected at barn exhaust fans were used for quantification and ranking of the odor impacts of target odorous gases. Fifteen target odorous VOCs (odorants) were selected. Air samples were collected at dairy barns in Wisconsin and Indiana and at swine barns in Iowa and Indiana over a one-year period. The livestock facilities with these barns participated in the National Air Emissions Monitoring Study (NAEMS). Gas concentrations, odor character and intensity, hedonic tone, and odor peak area of the target odorants in air samples were measured simultaneously with GCMS- O. The four individual odorants emitted from both dairy and swine sites with the largest odor impacts (measured as odor activity value, OAV) were 4-methyl phenol, butanoic acid, 3-methyl butanoic acid, and indole. The total odor (limited to target VOCs and referred to as the measured concentrations, odor intensities, and OAVs) emitted from the swine sites was generally greater than that from the dairy sites. The Weber-Fechner law was used to correlate measured odor intensities with chemical concentrations. Odorants with higher mean OAV followed the Weber-Fechner law much better than odorants with lower mean OAV. The correlations between odor intensities and chemical concentrations were much better for the swine sites (typically p < 0.05 and R² = 0.16 to 0.51) than for the dairy sites (typically p > 0.05 and R² < 0.15). Linking specific gases to odor could assist in the development and evaluation of odor mitigation technologies for solving livestock odor nuisance problems. [ABSTRACT FROM AUTHOR]

Economical and effective methods are needed to assess practices that reduce gas emissions. This project compared gas concentrations measured using semi-continuous sampling with dedicated gas analyzers versus concentrations obtained using 50 L FlexFoil bags filled over 24 h. Sampling was done over four months in summer and early fall of 2010 and 2011 from four biofilters (flat-bed with old media, A-frame, and two flat beds with either 10 cm or 5 cm screen birch mulch) treating air from deep manure pits below swine nurseries. Concentration ratios and percent reductions were calculated and compared using both sampling methods. The NH3, H2S, CO2, CH4, and N2O concentration data indicated that the 24 h bag sampling concentrations and percent reductions tracked the semi-continuous sampling concentrations and percent reductions well. Most (77%) of the NH3 concentrations differences (24 h bag sample minus semi-continuous) were within ±2 ppm of the semi-continuous concentrations, 78% of the H2S concentration differences were within ±200 ppb, 87% of the CH4 concentration differences were within ±10 ppm, and 88% of the N2O concentration differences were within ±75 ppb. Ratio means for NH3, CO2, and N2O were close to one (between 0.95 and 1.09). H2S ratio means varied from 0.61 in 2010 to 1.68 in 2011. Semi-continuous percent reduction results indicated that the four biofilters reduced NH3, H2S, and CH4 emissions. For three of the four biofilters, mean percent NH3 reductions ranged from 53% to 86%, mean percent H2S reductions ranged from 41% to 74%, and mean percent CH4 reductions ranged from 8% to 39%. One biofilter reduced N2O concentrations by 17% to 22%, while three biofilters generated N2O by 8% to 81%. The 24 h bag sampling system tested was an effective method for measuring gas concentrations and percent reductions of an air treatment system in the field based on NH3, CH4, and N2. [ABSTRACT FROM AUTHOR]

Foaming in deep manure pits beneath swine buildings has become a serious safety concern during the past few years in the Midwestern U.S. In addition to the loss of manure storage capacity, this foaming creates a serious safety risk of flash fires and explosions. In order to understand the mechanism of manure foaming, manure samples taken from foaming and non-foaming pits were studied to reveal potential causes. Among various compositional components found in the foaming and non-foaming manure samples, long-chain fatty acids (LCFA) were found to be a major contributing factor. Adding or removing LCFA in swine manure samples led to a significant change in their foaming capability. A significantly higher concentration of LCFA was also detected in the foam layers of foaming manure samples. LCFA surfactants are stimulating foaming, and the sources of these surfactants need to be determined in order to develop long-term mitigation plans for manure foaming. [ABSTRACT FROM AUTHOR]