Teng Teeh Lim

Methane and carbon dioxide emission from two pig finishing barns.

Agricultural activities are an important source of greenhouse gases. However, comprehensive, long-term, and high-quality measurement data of these gases are lacking. This article presents a field study of CH(4) and CO(2) emission from two 1100-head mechanically ventilated pig (Sus scrofa) finishing barns (B1 and B2) with shallow manure flushing systems and propane space heaters from August 2002 to July 2003 in northern Missouri. Barn 2 was treated with soybean oil sprinkling, misting essential oils, and misting essential oils with water to reduce air pollutant emissions. Only days with CDFB (complete-data-full-barn), defined as >80% of valid data during a day with >80% pigs in the barns, were used. The CH(4) average daily mean (ADM) emission rates were 36.2 +/- 2.0 g/d AU (ADM +/- 95% confidence interval; animal unit = 500 kg live mass) from B1 (CDFB days = 134) and 28.8 +/- 1.8 g/d AU from B2 (CDFB days = 131). The CO(2) ADM emission rates were 17.5 +/- 0.8 kg/d AU from B1 (CDFB days = 146) and 14.2 +/- 0.6 kg/d AU from B2 (CDFB days = 137). The treated barn reduced CH(4) emission by 20% (P < 0.01) and CO(2) emission by 19% (P < 0.01). The CH(4) and CO(2) released from the flushing lagoon effluent were equivalent to 9.8 and 4.1% of the CDFB CH(4) and CO(2) emissions, respectively. The emission data were compared with the literature, and the characteristics of CH(4) and CO(2) concentrations and emissions were discussed.

Quality-Assured Measurements of Animal Building Emissions: Particulate Matter Concentrations

Abstract Federally funded, multistate field studies were initiated in 2002 to measure emissions of particulate matter (PM) <10 μm (PM10) and total suspended particulate (TSP), ammonia, hydrogen sulfide, carbon dioxide, methane, non-methane hydrocarbons, and odor from swine and poultry production buildings in the United States. This paper describes the use of a continuous PM analyzer based on the tapered element oscillating microbalance (TEOM). In these studies, the TEOM was used to measure PM emissions at identical locations in paired barns. Measuring PM concentrations in swine and poultry barns, compared with measuring PM in ambient air, required more frequent maintenance of the TEOM. External screens were used to prevent rapid plugging of the insect screen in the PM10 preseparator inlet. Minute means of mass concentrations exhibited a sinusoidal pattern that followed the variation of relative humidity, indicating that mass concentration measurements were affected by water vapor condensation onto and evaporation of moisture from the TEOM filter. Filter loading increased the humidity effect, most likely because of increased water vapor adsorption capacity of added PM. In a single layer barn study, collocated TEOMs, equipped with TSP and PM10 inlets, corresponded well when placed near the inlets of exhaust fans in a layer barn. Initial data showed that average daily mean concentrations of TSP, PM10, and PM2.5 concentrations at a layer barn were 1440 ± 182 μg/m3 (n = 2), 553 ± 79 μg/m3 (n = 4), and 33 ± 75 μg/m3 (n = 1), respectively. The daily mean TSP concentration (n =1) of a swine barn sprinkled with soybean oil was 67% lower than an untreated swine barn, which had a daily mean TSP concentration of 1143 ± 619 μg/m3. The daily mean ambient TSP concentration (n = 1) near the swine barns was 25 ± 8 μg/m3. Concentrations of PM inside the swine barns were correlated to pig activity.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 6. Odor Activity Value

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.

ODOR FLUX MEASUREMENTS AT A FACULTATIVE SWINE LAGOON STRATIFIED BY SURFACE AERATION

Odor-related complaints are a major concern of pork producers. Open manure storage and treatment facilities such as uncovered anaerobic treatment lagoons are a major contributor to odor nuisance. Repeatable and valid field measurement techniques are needed for evaluating baseline odor emissions from existing livestock facilities and the effectiveness of odor abatement technologies. A buoyant convective flux chamber (BCFC) for measuring odor flux from liquid surfaces of dilute wastewaters was designed, constructed, and tested. Odor flux from a surface-aerated stratified facultative lagoon at a 6000-head swine finishing facility was measured with the BCFC. The swine buildings at this facility contained recirculation flush pits initially charged with about 0.5-m depth of effluent from the second cell of a two-stage lagoon system and discharged weekly to the first cell. The first cell was overloaded by 23% as an anaerobic lagoon with an estimated daily loading rate of about 118 g of volatile solids per m 3 of lagoon volume. To mitigate odor nuisance in the surrounding neighborhood, a static-tube aeration system was installed in the first cell in an attempt to create an oxygenated surface layer on an otherwise anaerobic lagoon. Odor flux measurements with the new BCFC appeared to exhibit good repeatability based on a limited number of tests. Odor flux of the stratified lagoon measured using a simulated wind speed of 1.1 m/s in the BCFC averaged 1.72 odor units per s per m 2 of lagoon surface area. The results are preliminary in terms of representing annual odor emission rates because odor flux is affected by wind and weather characteristics, results were based on only one constant wind speed that was simulated in the BCFC, and there were relatively few data points. The data was compared with odor flux measured at two unaerated anaerobic lagoons.

Characteristics of ammonia and carbon dioxide releases from layer hen manure

1. Ammonia (NH3) is an important gaseous pollutant generated from manure in commercial poultry farms and has been an environmental, ecological, and health concern. Poultry manure also releases carbon dioxide (CO2), which is a greenhouse gas and is often used as a tracer gas to calculate building ventilation. 2. A 38-d laboratory study was conducted to evaluate the characteristics of NH3 and CO2 releases from layer hen manure using 4 manure reactors (122 cm tall, 38 cm internal diameter), which were initially filled with 66 cm deep manure followed by weekly additions of 5 cm to simulate manure accumulation in commercial layer houses. 3. The average daily mean (ADM) NH3 and CO2 release fluxes for the 4 reactors during the entire study were 161⋅5 ± 21⋅1 µg/s.m2 (ADM ± 95% confidence interval) and 10⋅0 ± 0⋅3 mg/s.m2, respectively. The daily mean NH3 and CO2 releases in individual reactors varied from 35⋅2 to 679⋅1 µg/s.m2 and from 6⋅6 to 20⋅5 mg/s.m2, respectively. 4. The ADM NH3 release flux was within the range of those obtained in 4 high-rise layer houses by Liang et al. (2005, Transactions of the ASAE, 48). However, the CO2 release flux in this study was about 10 to 13 times as high as the data reported by Liang et al. (2005). Fresh manure had greater NH3 release potential than the manure in the reactors under continuous ventilation. Manure with higher contents of moisture, total nitrogen, and ammonium in the 4th weekly addition induced 11 times higher NH3 and 75% higher CO2 releases immediately after manure addition compared with pre-addition releases.

Ventilation rates in large commercial layer hen houses with two-year continuous monitoring.

1. Ventilation controls the indoor environment and is critical for poultry production and welfare. Ventilation is also crucial for assessing aerial pollutant emissions from the poultry industry. Published ventilation data for commercial layer houses have been limited, and are mostly based on short-term studies, mainly because monitoring airflow from large numbers of fans is technically challenging. 2. A two-year continuous ventilation monitoring trial was conducted at two commercial manure belt houses (A and B), each with 250 000 layers and 88 130-cm exhaust fans. All the fans were individually monitored with fan rotational speed sensors or vibration sensors. Differential static pressures across the house walls were also measured. Three fan performance assessment methods were applied periodically to determine fan degradations. Fan models were developed to calculate house ventilations. 3. A total of 693 and 678 complete data days, each containing >16 h of valid ventilation data, were obtained in houses A and B, respectively. The two-year mean ventilation rates of houses A and B were 2·08 and 2·10 m3 h−1 hen−1, corresponding to static pressures of −36·5 and −48·9 Pa, respectively. For monthly mean ventilation, the maximum rates were 4·87 and 5·01 m3 h−1 hen−1 in July 2008, and the minimum were 0·59 and 0·81 m3 h−1 hen−1 in February 2008, for houses A and B, respectively. 4. The two-year mean ventilation rates were similar to those from a survey in Germany and a 6-month study in Indiana, USA, but were much lower than the 8·4 and 6·2 m3 h−1 hen−1 from a study in Italy. The minimum monthly mean ventilation rates were similar to the data obtained in winter in Canada, but were lower than the minimum ventilation suggested in the literature. The lower static pressure in house B required more ventilation energy input. The two houses, although identical, demonstrated differences in indoor environment controls that represented potential to increase ventilation energy efficiency, and reduce carbon footprints and operational costs.

Emissions monitoring at a deep-pit swine finishing facility: Research methods and system performance

This paper describes part of a comprehensive National Air Emissions Monitoring Study (NAEMS) conducted at a swine finishing farm located in the state of Indiana, in the United States. The NAEMS was a 2-year study of emissions from animal feeding operations that produce pork, chicken meat, eggs, and milk. It provided emission data for the U.S. Environmental Protection Agency (EPA) to develop tools for estimating emissions from livestock farms. The study in Indiana focused on quantifying and characterizing emissions of gases, particulate matter (PM), and volatile organic compounds (VOCs) from a swine finishing quad (four 1000-head rooms under one roof). Long-term continuous and quasi-continuous measurements were conducted with 157 on-line measurement variables using an array of instruments and sensors for gas and PM concentrations, fan operation, room static pressures, indoor temperature and humidity, animal activity and feeding times, and weather conditions. Pig inventory and weight, feed type and quantity, and manure accumulation and composition were also documented. Systematic tests of the measurement system were conducted. Monitoring methodologies, instrumentation applications, equipment maintenance, quality controls, and system performances are presented and can be used as a reference in assessing research quality and improving future environmental studies on livestock facilities. Implications: Aerial pollutant emissions became a major environmental issue for livestock operations after farms increased significantly in size. Gas and particulate matter emissions from livestock production may cause various environmental impacts such as odor and noxious gas exposure in neighboring areas. In this study, comprehensive and long-term emissions of gases and PM at a Midwestern U.S. commercial swine finishing farm were continuously monitored for 2 years. The methodologies, quality assurance procedures, and results of this study can be used to plan future emission monitoring projects, improve baseline emission databases, and validate emission models.

Greenhouse Gas Emissions from a Large Commercial U.S. Dairy Farm

A long-term and comprehensive emission monitoring study was conducted at a large U.S. Midwest dairy farm. The monitoring effort was part of a national monitoring study that included swine, dairy, and poultry operations. The monitored farm was a 3400-cow operation. Monitoring of greenhouse gases (GHG) was conducted in two freestall barns and milking center for 28 months. The monitoring setup and equipment installation followed an approved site monitoring plan, a quality assurance project plan, and instrument or method-specific standard operating procedures. Gas concentrations, ventilation controllers, temperature and relative humidity, barn static pressure, and weather conditions were continuously monitored. In addition, animal inventory, mass, density, and milk production were recorded. As many as 563 valid daily mean data were obtained for each of the methane and carbon dioxide emissions between September 2007 and February 2010, and 98 daily means of valid nitrous oxide measurements that began on September 2009. The average daily mean (±SD) cow-specific emissions from identical freestall barns 1 and 2 were 12.6±1.9 and 12.1±2.0 kg d-1 hd-1, 373±80 and 356±74 g d-1 hd-1, and 564±919 and 551±852 mg d-1 hd-1 for carbon dioxide, methane, and nitrous oxide, respectively. Emissions were also normalized to individual cows, and units of floor area, milk production, and live mass. Methane and nitrous oxide contributed 42% and 0.7% to the total emissions of carbon dioxide equivalents (CO2 e). The total CO2 e emission rates (including the milking center) were 25.57 and 24.86 kg d-1 hd-1 for barns 1 and 2, respectively. Characteristics of the GHG emissions are presented and compared with the literature.

EFFECTS OF MANURE REMOVAL STRATEGIES ON ODOR AND GAS EMISSION FROM SWINE FINISHING

Odor, ammonia (NH3) and hydrogen sulfide (H2S) concentrations and emission rates were measured in two small rooms of finishing pigs with different manure removal strategies. The strategies included daily flush, and static pits with 7-, 14-, and 42-d storage times with and without pit recharge. Tests were conducted with three successive groups of 25 pigs per room. Pigs were fed standard corn-soybean diets. Ammonia and H2S concentrations were automatically measured 15 to 24 times per day. Odor samples were collected and evaluated for odor concentration, intensity and hedonic tone by an odor panel, whose performance was verified with a reference odorant. Geometric mean odor emission rates were 19, 33, and 29 OUE s-1 AU-1 (OUE = European odor unit equivalent to 123 µg n-butanol, AU = 500 kg live mass) for 1-d (daily flush), 7-d, and 14-d manure storage times without pit recharge, respectively, and 2.6 and 25 OUE s-1 AU-1 for 7- and 42-d manure storage times with pit recharge, respectively. Mean NH3 emission rates were 14, 23, and 22 g d-1 AU-1 for 1-, 7- and 14-d manure storage times without pit recharge and 5.7, 6.8 and 7.2 g d-1 AU-1 for 7-, 14-, and 42-d manure storage times with pit recharge, respectively. Mean H2S emission rates were 0.11, 0.23 and 0.37 g d-1 AU-1 for 1-, 7- and 14-d manure storage times without pit recharge and 0.08, 0.19 and 0.91 g d-1 AU-1 for 7-, 14-, and 42-d manure storage times with pit recharge, respectively. The H2S emission rate for the 1-d storage was 0.41g d-1 AU-1 as compared with 0.11 g d-1 AU-1 when including burst emissions during flushing. Sudden emissions during flushing are not expected to influence mean emissions as much in a typical finishing building. The highest mean emission rates were equivalent to 44 and 1,146 kg yr-1 for H2S and NH3 from a 1,000-head finishing house, respectively. The data showed that lower emission rates occur when pits are recharged after emptying, and when pits are emptied more frequently.

Field Tests of a Particulate Impaction Curtain on Emissions from a High-Rise Layer Barn

Particulate matter (PM) emission rates from two high-rise layer barns (barns 1 and 2) were measured from August 1, 2004 to January 31, 2005. A commercial particulate impaction curtain (PIC) installed parallel to the pit sidewalls of barn 2 removed PM by impaction. Particulate matter before and after the PIC were monitored with the Tapered Element Oscillating Microbalance (TEOM) for PM10 over a 48-hr period once or twice per week with a gravimetric sampler for total suspended particulate (TSP). Average untreated daily mean PM10 emission were 30 and 35 mg d-1 hen-1, while mean TSP emissions were 281 (control) and 152 mg/s (treated) from barns 1 and 2, respectively. The mean treated PM10 emission rate was 22 mg d-1 hen-1 and was decreased by 41% based on measurements before and after the PIC, but some dilution occurred from backflow through nonoperating fans. Some important practical issues currently hinder the use of PIC in high-rise layer barns.