Ammonia and Greenhouse Gas Emissions of a Modern U.S. Swine Breeding-Gestation-Farrowing Facility

Transcription

1 Agricultural and Biosystems Engineering Conference Proceedings and Presentations Agricultural and Biosystems Engineering Ammonia and Greenhouse Gas Emissions of a Modern U.S. Swine Breeding-Gestation-Farrowing Facility John P. Stinn John P. Stinn Iowa State University, elwayjr1@iastate.edu Hongwei Xin Iowa State University, hxin@iastate.edu Timothy A. Shepherd Iowa State University, tshep@iastate.edu Hong Li University of Delaware See Follow next page this for and additional additional authors works at: Part of the Agriculture Commons, and the Bioresource and Agricultural Engineering Commons The complete bibliographic information for this item can be found at abe_eng_conf/345. For information on how to cite this item, please visit howtocite.html. This Conference Proceeding is brought to you for free and open access by the Agricultural and Biosystems Engineering at Digital Iowa State University. It has been accepted for inclusion in Agricultural and Biosystems Engineering Conference Proceedings and Presentations by an authorized administrator of Digital Iowa State University. For more information, please contact digirep@iastate.edu.

2 Authors John P. Stinn, John P. Stinn, Hongwei Xin, Timothy A. Shepherd, Hong Li, and Robert T. Burns This conference proceeding is available at Digital Iowa State University:

3 An ASABE Meeting Presentation Paper Number: Ammonia and Greenhouse Gas Emissions of a Modern U.S. Swine Breeding-Gestation-Farrowing Facility John P. Stinn a Hongwei Xin, Ph.D. a Timothy A. Shepherd a Grad Research Assistant Professor Assistant Scientist Hong Li, Ph.D. b Robert T. Burns, Ph.D. c Assistant Professor Professor and Assistant Dean a Department of Ag. & Biosystems Engineering, Iowa State University, Ames, IA 511, USA b Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, USA c University of Tennessee, 12 Morgan Hall, Knoxville, TN 37996, USA Written for presentation at the 213 ASABE Annual International Meeting Sponsored by ASABE Kansas City, Missouri July 21 24, 213 Abstract. Aerial emissions from livestock production continue to be an area of concern for both the potential health and environmental impacts. However, information on gaseous, especially greenhouse gas (GHG) emissions for swine breeding/gestation and farrowing production facilities is meager. A 43-sow breeding, gestation, and farrowing facility in Iowa was selected for extensive field monitoring. A Mobile Air Emission Monitoring Unit (MAEMU) was installed to monitor the deep-pit breeding-early gestation barn (18 head), the deep-pit late gestation barn (18 head), and two shallow-pit (pull-plug) farrowing rooms (4 head per room). A dynamic flux chamber was used to monitor gaseous emissions from the external manure storage for the farrowing rooms. This paper reports on data collected from January 12, 211 through the completion of the study June 3, 213. At the time of this abstract writing, results from the study show the following average daily emissions per sow or sow+litter: 13.5 g NH 3, 2.87 kg CO 2,.9 g N 2 O, and 12 g CH 4 for sows in the breeding/early gestation barn; 13.1 g NH 3, 3. kg CO 2,.8 g N 2 O, and 94 g CH 4 for sows in the late gestation barn; 32. g NH 3, 8.7 kg CO 2,.35 g N 2 O, and 57.7 g CH 4 for sows and litters in the farrowing rooms. The average daily emissions per sow+litter for the external manure storage for the farrowing facility are 6.6 g NH 3, 1.1 kg CO 2,.88 g N 2 O, and 722 g CH 4. Farm-level average daily emissions per sow are 17.5 g NH 3, 4.12 kg CO 2,.11 g N 2 O, and 149 g CH 4. Keywords. Ammonia, Greenhouse Gas, Aerial Emissions, Deep-pit, Swine Gestation and Farrowing. Introduction The authors are solely responsible for the content of this meeting presentation. The presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Meeting presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an ASABE meeting paper. EXAMPLE: Author s Last Name, Initials Title of Presentation. ASABE Paper No St. Joseph, Mich.: ASABE. For information about securing permission to reprint or reproduce a meeting presentation, please contact ASABE at rutter@asabe.org or (295 Niles Road, St. Joseph, MI USA).

4 Gaseous emissions from livestock production facilities have received increasing attention as concern has grown over their environmental and health impacts. It is important to study these emissions to understand the quantity and compositions of gasses being emitted to the atmosphere. The three biggest gasses of concern in terms of having potential to affect climate change are the greenhouse gasses (GHG): carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ). In order to understand the magnitude of GHG emissions from livestock production, reliable emission factors for different livestock production systems in different geographic/climatic areas must be determined. Currently, there is a gap in the GHG emissions data for swine breeding/gestation and farrowing stages of production. The US breeding pig inventory was 5.83 million head as of March 28, 213 and Iowa leads the US with over 17% of the breeding inventory (USDA NASS, 213). The US EPA estimates that agriculture is responsible for 6.3% of the total GHG emissions in the US (211 US Greenhouse Gas Inventory Report). Literature information on GHG emissions from swine gestation and farrowing facilities is limited. The gestation side is particularly sparse as many of the studies done are for shallow-pit or flush systems, not the deep-pit system common in the Midwest. The literature for farrowing facility emissions is more comparable due to the common manure management practice of shallow-pit systems but is still meager. Additionally, many of these studies involved intermittent air sampling, which can struggle to capture the diurnal fluctuations of gaseous emissions and can be significantly impacted by short-term weather conditions. Therefore, the objective of this study was to quantify the emissions of GHG and ammonia from a Midwestern swine breeding/gestation/farrowing facility. Twenty-nine months of data collection was completed. Materials and Methods Site Description and Instrumentation A 43-sow capacity breeding/gestation/farrowing facility in central Iowa was used in this monitoring study. A full description of the facility and instrumentation can be found in Stinn et al. (211). In brief, the facility consisted of two farrowing buildings with 9 farrowing rooms each, a breeding/early gestation barn, a late gestation barn, and an external manure storage vat for the farrowing facility. Two farrowing rooms, designated Room 1 and Room 2, were selected to be monitored. The farrowing rooms were each 15.5m x 13.9m (51ft x 45.5ft) with a shallow-pit system (.61m deep) that was flushed out after every turn (approx. every 21 days). Figure 1 shows the monitoring system layout for the farrowing rooms. Each room's exhaust air was sampled identically, with one composite sample from the shallow-pit fans and one composite sample from the lowest stage wall fans. The breeding/early gestation barn and the late gestation barn, designated as Barns 1 and 2, respectively, had the same dimensions, ventilation design, and 18-head capacity. The barns had dimensions of 121.9m x 3.5m (4ft x 1ft) each and used mechanical ventilation year-round. Each barn had a deep pit (3.5 m) and the manure was pumped out semi-annually, in the fall and spring. Figure 2 shows the monitoring system layout for Barns 1 and 2. Exhaust air samples from each barn were drawn as a composite from four of the lowest ventilation stage pit fans with a second sample from the lowest stage endwall fans. A Mobile Air Emissions Monitoring Unit (MAEMU) was used to continuously collect emissions data from the previously described barns and farrowing rooms. A detailed description of the MAEMU and its operation can be found in Moody et al. (28). The MAEMU housed, among other measurement and data acquisition equipment, a photoacoustic multi-gas analyzer (INNOVA Model 1412, INNOVA AirTech Instruments A/S, Ballerup Denmark) to measure NH 3, CO 2, N 2 O, and CH 4 concentrations. The analyzer was challenged weekly with calibration gasses and recalibrated as needed. Samples were drawn from the 8 in-house locations and 1 outside location to provide ambient background data. Samples were drawn from each in-house location every 16 min (2 min per location) with the outside air being sampled every two hours for 6 min (12 samples). The outside location can be seen in Figure 2 on the north side of Barn 2. Pit fan sampling ports were located below the slats/floor directly under each fan. Wall fan sampling ports were located approximately 1. m (3.28 ft) in front of each wall fan. The sample port locations were chosen to best represent the exhaust air leaving each barn/room. The MAEMU utilized a positivepressure gas sampling system to minimize potential infusion of unwanted air to the sample line. All pumps and sample lines were checked weekly for leaks and blockages. 213 ASABE Annual International Meeting Paper Page 1

5 Figure 1. Diagram of Farrowing Rooms 1 and 2 showing air sampling, temperature, static pressure, and relative humidity measurement locations. Figure 2. Diagram of Barns 1 and 2 showing air sampling, temperature, static pressure, relative humidity, and barometric pressure measurement locations. 213 ASABE Annual International Meeting Paper Page 2

6 The ventilation fans were calibrated in situ at multiple operating points to develop a performance curve for each fan using a Fan Assessment Numeration System (FANS) (Gates et al., 24). The on/off status of each fan was monitored continuously by an inductive current switch on the each fan motor's power cord (Muhlbauer et al., 211) with its analog output connected to the data acquisition system. The speed of the variable speed fans was measured by Hall Effect speed sensors (GS171, Cherry Corp, Pleasant Prairie, WI). Static pressure sensors were located near the south wall of each farrowing room and near the middle of the north and south walls in Barns 1 and 2. The external manure storage vat had a diameter of 48.8m (16 ft) and a depth of 4.57m (15 ft), but management did not allow manure depth to exceed 3.5m (1 ft) until the last three months of the study. Manure originated in the farrowing rooms and was added every day from the farrowing room that was being weaned. The vat was pumped twice a year, in the fall and spring. A dynamic flux chamber system was developed similar to Acevedo et al. (29). The chamber was floated on the vat manure surface for a range of ambient conditions and gas concentrations were measured with an Innova 1412 photoacoustic analyzer. Figure 3 shows the floating dynamic flux chamber. Gaseous Emission Rate Determination Emission rates from the barns for each measured constituent were calculated as mass of the gas emitted per unit time using Equation 1 (Stinn, et al., 211): 1 Where ER G = Gas emission rate for the house, g hr -1 house -1 Q = Incoming and exhaust ventilation rate of the house at field temperature and barometric pressure, respectively, m 3 hr -1 house -1 [G] i, [G] e = Gas concentration of incoming and exhaust ventilation air, respectively, ppmv W = Molar weight of the gas, g mole -1 (e.g., for NH 3 ) V = Molar volume of gas at standard temperature ( C) and pressure ( kpa) or STP, m 3 mole -1 T std = Standard temperature, K T a = Ambient air temperature ρ i, ρ e = Density of incoming and exhaust air, respectively, g cm -3 P std = Standard barometric pressure, kpa P a = Atmospheric barometric pressure at the monitoring site, kpa Emission flux rates (F) from the manure storage vat were calculated as mass of gas emitted per unit time per unit area using Equation 2 (Acevedo et al., 29): 1 (2) Where F = Flux, g hr -1 m -2 Q c = Incoming flow rate of the chamber, L min -1 [G] i, [G] e = Gas concentration of incoming and exhaust ventilation air, respectively, ppmv W = Molar weight of the gas, g mole -1 (e.g., for NH 3 ) V = Molar volume of gas at standard temperature ( C) and pressure ( kpa) or STP, m 3 mole -1 T std = Standard temperature, K T a = Sample air temperature P std = Standard barometric pressure, kpa P a = Barometric pressure, kpa A c =Flux chamber area,.84 m 2 (1) Figure 3. Dynamic flux chamber floating on manure storage vat. 213 ASABE Annual International Meeting Paper Page 3

7 Results and Discussion The results presented in this paper are form data collected January 12, 211 to June 3, 213 and are considered to be preliminary. Figure 3 shows the average daily ventilation rates for each monitored barn and room versus the average daily temperatures over the monitoring period. Table 1 shows the average daily ventilation and emission rates of each constituent for each barn and room and values for the average of the two farrowing rooms. Ventilation Rate (m 3 /hr/head) Barn 1 Barn 2 Ventilation Rate (m3/hr/head) Room 1 Room 2 Ambient Temperature, C Ambient Temperature, C (a) (b) Figure 4. Average daily ventilation rate of (a) Barns 1 and 2 and (b) Rooms 1 and 2 versus average daily ambient temperature during the 29-month monitored period. Table 1. Average (SD in parentheses) gaseous emission rates (g/d-sow or g/d/sow+litter of the two monitored breeding/gestation barns and two monitored farrowing rooms. Source # of Days Monitored # Pigs or Crates VR (m 3 /hr-pig) Gaseous Emission Rate (g/d-sow or g/d-(sow+litter)) NH 3 CO 2 N 2 O CH 4 Barn 1 Barn 2 Room 1 Room (77) 13.5 (4.6) 2878 (776).9 (.15) 11.9 (39.8) (81) 13.1 (3.9) 329 (82).5 (.11) 93.5 (36.) (24) 3.5 (13.6) 8667 (4645).32 (.48) 54.8 (26.3) (271) 33.5 (14.6) 871 (4297).36 (.49) 6.5 (28.4) Breeding/Gestation Average Farrowing Room Average 112 (79) 13.3 (4.2) 2957 (79).8 (.14) 97.5 (37.9) 338 (256) 32. (14.1) 8689 (4471).35 (.52) 57.7 (27.3) *Average animal weights estimated to be 187 kg/sow in Barn 1, 198 kg/sow in Barn 2, and 22 kg/(sow+litter) in Farrowing Rooms Figure 5 shows emission rates from the external manure storage as measured by the dynamic flux chamber at an air exchange rate of 3 air changes per hour (ACH). The emissions rates were correlated to the average daily ambient temperature, which allowed the flux values to be extrapolated for the entire monitoring period. Table 2 shows the average flux rates from the manure surface, in g/m 2 /hr, using the best fit lines from Figure 5 and the average daily ambient temperatures. This rate can then be converted to an emission rate on a per sow+litter basis for easier comparison to the monitored farrowing rooms. 213 ASABE Annual International Meeting Paper Page 4

8 Emission Rate, g/(m 2 hr) y =.12x +.46 R² = Ambient Temperature, ºC Emission Rate, g/(m 2 hr) y =.243x R² = Ambient Temperature, ºC (a) (b) Emission Rate, g/(m 2 hr) y =.2x.7 R² = Ambient Temperature, ºC Emission Rate, g/(m 2 hr) y =.1591x R² = Ambient Temperature, ºC (c) (d) Figure 5. Average emission rates for (a) ammonia, (b) carbon dioxide, (c) nitrous oxide, and (d) methane from external manure storage measured with dynamic flux chamber at 3 air changes per hour. Table 2. Average (SD in parentheses) flux rates from the external manure storage surface and emission rates on a sow+litter basis for comparison with [farrowing] barn emission measurements. Emission Rate Unit NH 3 CO 2 N 2 O CH 4 g/m2-hr.148 (.127) 2.96 (2.54).243 (.21) 1.87 (1.64) g/d-(sow+litter).485 (.416) 9.69 (8.32).796 (.688) 6.12 (5.37) Zhu et al. (2) measured NH 3 emissions from several swine facilities in Minnesota, including a deep-pit gestation and deep-pit farrowing building. The gestation building had an emission rate of.7 to.14 g/hm 2, which when scaled to Barns 1 and 2 gave a range of.757 to kg/d-barn. This is far below the measured 22.9 and 24.1 kg/d-barn from Barns 1 and 2. For the farrowing barns, Zhu et al. reported a range of.1 to.18 g/h-m 2, which would scale to.362 to.931 kg/d-room. This was again lower than the measured 1.3 and 1.4 kg/d-room for Rooms 1 and 2. Zhang et al. (27) measured GHG emissions from two mechanically-ventilated farrowing farms. The farrowing barns followed the same 3-week pit-flushing period as used for Rooms 1 and 2. Emission rates of CH 4 ranged from 73 to 351 g/d-au, encompassing the measured emission rates of 125 and 138 g/d-au of our current study. Zhang et al. also reported CO 2 emission rates of 16,588 and 11,576 g/d-au, which were lower than the measured 19,7 and 19,8 g/d-au emission rates in the current study. Zhang et al. did not measure any significant N 2 O emissions, while the emissions from Rooms 1 and 2 had an identical average of.8 g/d-au. As discussed previously, NH 3, CO 2, and N 2 O emissions observed in the current study were higher than literature values for comparable systems. One major difference between this study and previous studies is the monitoring duration used for both gas concentrations and ventilation rates. Zhang et al. (27) collected one air sample per farrowing room per day for 19 different dates from September to October 23 and from June to September 24. At the time of each air sample, the ventilation rate was measured for each running fan using a hot-wire anemometer. Zhu et al. (2) collected air samples every two hours for a single 12-hour period. Ventilation rate was estimated by measuring static pressure difference across each running fan and referring to 213 ASABE Annual International Meeting Paper Page 5

9 fan rating tables. Neither of these studies accounted for seasonal or diurnal variations in emission rates. The more frequent sampling used in the current study at each location (every 16 min) and continual monitoring of building and environment conditions (fan status, static pressure, temperature, etc.) over a much longer period (29 consecutive months) is expected to better capture the emission dynamics associated with production stage (animal body weight, feed intake, manure accumulation, etc.) and climatic conditions, and thus give a more realistic quantification of the daily emission rate. A challenging dynamic of the farrowing rooms was the rapid body weight increase of the piglets post birth. Quantification of these growth curves is ongoing in conjunction with a separate project. Figure 6 shows the daily emission rate of ammonia from a farrowing room over a turn during (a)cold and (b)warm ambient conditions. Figure 6a shows the increase in ammonia emissions as manure accumulates in the shallow pit and ventilation is forced to increase to meet the increasing heat production of the growing piglets. This is less noticeable in warm conditions (Figure 6b) as the ventilation rates are elevated for temperature control instead of depressed to the moisture control range. Ammonia Emission Rate, g/day NH3 ER Amb Temp Day of Turn Ambient Temperature, C Ammonia Emission Rate, g/day NH3 ER Amb Temp Day of Turn Ambient Temperature, C (a) (b) Figure 6. Daily ammonia emission rates over two farrowing turns for (a)cold and (b)hot ambient conditions The emissions can also be examined from a whole farm perspective (Table 3). As shown in Table 4, the manure storage contributes a small percentage of the farm s NH 3 and CO 2 emissions, but a significant portion of the N 2 O and CH 4 emissions. The three barn sources show fairly even contribution to NH 3 and CO 2 emissions, but the Farrowing Barns account for a small percentage of the farm CH 4 emissions. The low CH 4 emission from the Farrowing Barns is due to the short retention time for manure in the shallow pits (~21 days) as compared to the much longer retention times in the other barns or manure storage (~6 months). Table 3. Farm-level emission rates (SD in parentheses) on a gram per day per sow basis NH 3 CO 2 N 2 O CH 4 Whole Farm Emission Rate, g/day-sow 17.5 (2.96) 4128 (968).11 (.17) 149 (25.2) Table 4. Percent of whole farm emissions for each major source: Barn 1, Barn 2, Farrowing Barns, and External Manure Storage Source Percent of Whole Farm Emissions NH 3 CO 2 N 2 O CH 4 Breeding/Gestation Barns 64% 6% 5% 55% Farrowing Barns 32% 37% 33% 7% Manure Storage 3% 2% 62% 38% 213 ASABE Annual International Meeting Paper Page 6

10 Conclusion The results of this study to date indicate that gaseous emission rates from the Midwest swine breeding, gestation and farrowing facility are possibly higher than the current literature values in all cases except for CH 4 emissions from the farrowing rooms. The higher emission rates are likely due to this facility being a deep-pit system for Barns 1 (breeding and early gestation) and 2 (late gestation) and the nearly continuous sampling employed in this study as compared to the intermittent sampling used in the literature studies. From a whole farm emissions standpoint, the manure storage is the major source of methane emission, followed by Barn 1 and Barn 2. The two gestation barns and the farrowing barns emit similar amounts of ammonia. The project concluded monitoring in early June 213 and final data processing is under way. Acknowledgements Funding for the study was provided in part by the Iowa Pork Producers Association and in-kind contribution of the Mobile Air Emissions Monitoring Unit by Iowa State University. We also thank the swine producer for providing access to the facility and cooperation during the project. References Acevedo, R.R., H. Li, H. Xin, S. Roberts. 29. Evaluation of a Flux Chamber for Assessing Gaseous Emissions and Treatment Effects of Poultry Manure. ASABE Paper # St. Joseph, MI: ASABE. EPA Inventory of Greenhouse Gas Emissions and Sinks: Washington, DC. United States Environmental Protection Agency. Gates, R. S., D. K. Casey, H. Xin, E. F. Wheeler, J.D. Simmons. 24. Fan Assessment Numeration System (FANS) design and calibration specifications. Transactions of the ASAE 47(6): Moody, L., H. Li, R. Burns, H. Xin, R. Gates. 28. A Quality Assurance Project Plan for Monitoring Gaseous and Particulate Matter Emissions from Broiler Housing. ASABE #913C8e. St. Joseph, Michigan. Muhlbauer R.V., T.A. Shepherd, H. Li, R.T. Burns, H. Xin Technical Note: Development and application of an inductionoperated current switch for monitoring fan operation. Applied Engineering in Agriculture 27(2): Pepple, L.M., R.T. Burns, H. Xin, H. Li, J. Patience Ammonia, Hydrogen Sulfide, and Greenhouse Gas Emissions from Wean-to-Finish Swine Barns Fed Traditional vs. a DDGS Based Diet. ASABE # St. Joseph, Michigan. Stinn, J., H. Xin, H. Li, T. Shepherd, R. Burns Quantification of greenhouse gas and ammonia emissions from a Midwestern swine breeding/gestation/farrowing facility. ASABE Paper # St. Joseph, MI: ASABE USDA, 213. Quarterly Hogs and Pigs. USDA Reference No United States Department of Agriculture and National Agriculture Statistics Service. Zhang, Q., X. Zhou, N.Cicek, M. Tenuta. 27. Measurement of odor and greenhouse gas emissions in two swine farrowing operations. Canadian Biosystems Engineering 49: Zhu, T., L. Jacobson, D. Schmidt, R. Nicolai. 2. Daily variations in odor and gas emissions from animal facilities. Applied Engineering in Agriculture 16(2): ASABE Annual International Meeting Paper Page 7