Search

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]

This study supplemented the National Air Emissions Monitoring Study (NAEMS) with one year of comprehensive measurements of odor emission at five swine and four dairy buildings. The measurements included both standard human sensory measurements using dynamic forced-choice olfactometry and chemical analysis of the odorous compounds using gas chromatography-mass spectrometry. In this article, multilinear regressions between odor and gas concentrations (a total of 20 compounds including H2S, NH3, and VOCs) were investigated. Regressions between odor and gas emission rates were also tested. It was found that gas concentrations, rather than emission rates, should be used to develop multilinear regression models. For the dairy sites, H2S, NH3, acetic acid, propanoic acid, 2-methyl propanoic, and pentanoic acids were observed to be the compounds with the most significant effect on sensory odor. For the swine sites, in addition to these gases, higher molecular weight compounds such as phenol, 4-methyl phenol, 4-ethyl phenol, and 1H-indole were also observed to be significant predictors of sensory odor. When all VOCs were excluded from the model, significant correlations between odor and H2S and NH3 concentrations were still observed. Although these coefficients of determination were lower when only H2S and NH3 were used, they can be used to predict odor variability by up to 83% when VOC data are unavailable. [ABSTRACT FROM AUTHOR]

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions considering variations in seasons, animal types, and olfactometry laboratories. Odor emissions from four of 14 NAEMS sites with nine barns/rooms (two dairy barns at the WI5B and IN5B sites, two pig finishing rooms at IN3B, and two sow gestation barns and a farrowing room at the IA4B site) were measured during four 13-week cycles. Odor emissions were reported per barn area (OU h-1 m-2), head (OU h-1 head-1), and animal unit (OU h-1 A U-1). The highest overall odor emission rates were measured in summer (1.2 x 105 OU h-1 m-2, 3.5 x 105 OU h-1 head-1, and 6.2 x 105 OU h-1 AU-1), and the lowest rates were measured in winter (2.5 x 104 OU h-1 m-2, 9.1 x 104 OU h-1 head-1, and 1.5 x 105 OU h-1 AU-1). The highest ambient odor concentrations and barn odor emissions were measured from the sow gestation barns of the IA4B site, which had unusually high H2S concentrations. The most intense odor and the least pleasant odor were also measured at this site. The overall odor emission rates of the pig finishing rooms at IN3B were lower than the emission rates of the IA4B sow gestation barns. The lowest overall barn odor emission rates were measured at the IN5B dairy barns. However, the lowest ambient odor concentrations were measured at the ventilation inlets of the WI5B dairy barns. [ABSTRACT FROM AUTHOR]

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include inputs to odor setback models, while chemical emission factors may be compared with regulation thresholds as a means of demonstrating potential health impacts. A companion study of the National Air Emissions Monitoring Study (NAEMS) included measurements necessary for establishing odor and chemical emission factors for confined animal feeding operations. This additional investigation was conducted by the University of Minnesota, Iowa State University, West Texas A&M Agri-Life Center, and Purdue University. The objectives were to (1) determine odor emission rates across swine and dairy facilities and seasons using common protocols and standardized olfactometry methods, (2) develop a chemical library of the most significant odorants, and (3) correlate the chemical library with the olfactometry results. This document describes the sampling and quality assurance methods used in the measurement and evaluation of odor and chemical samples collected at two freestall dairy farms, one sow (gestation/farrowing) facility, and one finishing pig site. Odor samples were collected in Tedlar bags and chemical samples were collected in sorbent tubes at barn inlet and exhaust locations using the NAEMS multiple-location gas sampling systems. Quality assurance protocols included interlaboratory comparison tests, which were evaluated to identify variations between olfactometry labs. While differences were observed, the variations among the labs and samples appeared random and the collected odor data were considered reliable at a 0.5% level of statistical significance. Overall, the study took advantage of groundbreaking opportunities to collect and associate simultaneous odor and chemical information from swine and dairy buildings while maintaining accordance with standard methods and comparability across laboratories. [ABSTRACT FROM AUTHOR]

There is a growing concern with air and odor emissions from agricultural facilities. A supplementary research project was conducted to complement the U.S. National Air Emissions Monitoring Study (NAEMS). The overall goal of the project was to establish odor and chemical emission factors for animal feeding operations. The study was conducted over a 17-month period at two freestall dairies, one swine sow farm, and one swine finisher facility. Samples from a representative exhaust airstream at each barn were collected in 10 L Tedlar bags and analyzed by trained human panelists using dynamic triangular forced-choice olfactometry. Samples were simultaneously analyzed for 20 odorous compounds (acetic acid, propanoic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, guaiacol, phenol, 4-methylphenol, 4-ethylphenol, 2-aminoacetophenone, indole, skatole, dimethyl disulfide, diethyl disulfide, dimethyl trisulfide, hydrogen sulfide, and ammonia). In this article, which is part 6 of a six-part series summarizing results of the project, we investigate the correlations between odor concentrations and odor activity value (OAV), defined as the concentration of a single compound divided by the odor threshold for that compound. The specific objectives were to determine which compounds contributed most to the overall odor emanating from swine and dairy buildings, and develop equations for predicting odor concentration based on compound OAVs. Single-compound odor thresholds (SCOT) were statistically summarized and analyzed and OAVs were calculated for all compounds. Odor concentrations were regressed against OAV values using multivariate regression techniques. Both swine sites had four common compounds with the highest OAVs (ranked high to low: hydrogen sulfide, 4-methylphenol, butyric acid, isovaleric acid). The dairy sites" had these same four compounds in common in the top five, and in addition diethyl disulfide was ranked second at one dairy site, while ammonia was ranked third at the other dairy site. Summed OAVs were not a good predictor of odor concentration (R² = 0.16 to 0.52), underestimating actual odor concentrations by 2 to 3 times. Based on the OAV and regression analyses, we conclude that hydrogen sulfide, 4-methylphenol, isovaleric acid, ammonia, and diethyl disulfide are the most likely contributors to swine odor while hydrogen sulfide, 4-methyl phenol, butyric acid, and isovaleric acid are the most likely contributors to dairy odors. [ABSTRACT FROM AUTHOR]

This article compares results of using dynamic triangular forced-choice olfactometry (DTFCO), the Mask Scentometer, the Nasal Ranger, and an odor intensity reference scale (OIRS) to assess odors in a controlled-environment chamber in the Iowa State University Air Dispersion Laboratory. The methods were used to assess 13 odor levels in the chamber. Swine manure mixed with water was used to vary the odor levels. DTFCO did not correlate well to the other ambient odor assessment methods. Predicting dilution to threshold (D/T) using intensity ratings compared to using intensity ratings directly degraded the coefficient of determination (Ro2) through zero with the other methods in all cases. Average intensity-predicted D/T, the Mask Scentometer, and the Nasal Ranger correlated well with each other, with strong Ro2 values (greater than 0.85) and regression slopes near 1, and the session means were not found to be significantly different (α = 0.05). Using the geometric means of the device D/T settings, (D/T)G , improved the Ro2 values between the other methods and the Nasal Ranger and Mask Scentometer. Average intensity-predicted D/T values were three to four times higher than Nasal Ranger assessment ((D/T)G and D/T, respectively), and Nasal Ranger (D/T)G was roughly five times higher than Mask Scentometer (D/T)G . [ABSTRACT FROM AUTHOR]

Limited data exist in the literature regarding air emissions front U.S. turkey feeding operations. The project described in this article continuously monitored ammonia (NH3) and particulate matter (PM) emissions front turkey production houses in Iowa (IA) and Minnesota (MN) for 10 to 16 months, with IA monitoring Hybrid tom turkeys (35 to 143 d of age, average market body weight of 17.9 kg) for 16 months and MN monitoring Hybrid hens (35 to 84 d of age, average market body weight of 6. 7 kg) for 10 months. Mobile air emission monitoring units (MAEMUs) were used in the continuous monitoring. Based on the approximately one-year measurement, each involving three flocks of birds, daily NH3, PM10, and PM2.5 concentrations (mean ±SD) in the tom turkey barn were 8.6 + 10.0 ppm, 1104 ± 719 µg m-3, and 143 (±124)µg m-3, respectively. Daily NH3 and PM10 concentrations (mean ±SD) in the hen turkey barn were 7.3 ± 7.9 ppm and 301 ± 160 µg m-3, respectively. Daily NH3 concentrations during downtime (mean ±SD) were 38.4 ± 20.5 and 20.0 ± 16.3 ppm in the tom and hen barns, respectively. The cumulative NH3 emissions (mean ±SE) were 141 ± 13.1 and 1.8 ± 0.9 g bird-1 for the tom turkeys during 108 d growout and 13 d downtime, respectively, and 52 ± 2.1 and 28.2 ± 2.5 g bird-1 for the hen turkeys during 49 d growout and 32 d downtime, respectively (the extended downtime for the hen house was to ensure monitoring of one flock per season). The cumulative PM10 emission (mean ±SE) was 28.2 ± 3.3 g bird-1 for the tom turkeys during 108 d growout and 4.6 ± 2.2 and 0.3 ± 0.06 g bird-1 for the hen turkeys during 49 d growout and 32 d downtime, respectively. Downtime in the hen house was of greater duration than would be typically observed (32 d vs. 7 d to 14 d typical). The cumulative PM2.5 emission (mean ± SE) was 3.6 ± 0.7 g bird-1 for the tom turkeys during 108 d growout (not monitored for the hen turkeys). Because farm operations will vary in flock number, growout days, and downtime; annual emissions can be calculated front the cumulative emissions and downtime emissions per bird from the data provided. Air emissions data from this study, presented in both daily emission and cumulative per-bird-marketed emission, contribute to the improved U.S. national air emissions inventory for animal feeding operations. [ABSTRACT FROM AUTHOR]