Kenneth D. Casey

Fan Assessment Numeration System (FANS) Design and Calibration Specifications

A device for insitu fan airflow measurement, known as the Fan Assessment Numeration System (FANS) device, previously developed and constructed at the USDAARS Southern Poultry Research Laboratory, was refined at University of Kentucky as part of a project for quantifying building emissions from mechanically ventilated poultry and livestock facili- ties. The FANS incorporates an array of five propeller anemometers to perform a realtime traverse of the airflow entering fans of up to 137 cm (54 in.) diameter. Details of the updated design, including hardware, software, and calibration methodolo- gy are presented. An error analysis of the flow rate, and calibration results from ten FANS units, is provided. Sufficient details of fabrication and calibration are presented so that interested readers can replicate a FANS for their use. Full design details are available at www.bae.uky.edu/IFAFS/FANS.htm.

Ammonia Emissions from U.S. Laying Hen Houses in Iowa and Pennsylvania

Ammonia (NH3) emission rates (ER) of ten commercial layer houses (six high-rise or HR houses and four manure- belt or MB houses) with different manure handling or dietary schemes were monitored for one year in Iowa (IA) and Pennsylvania (PA). Gaseous (NH3 and CO2) concentrations of incoming and exhaust air streams were measured using custom-designed portable monitoring units that shared similar performance to EPA-approved measurement apparatus. Building ventilation rates were determined by calibrated CO2 mass balance using the latest metabolic rate data for modern laying hens. The field monitoring involved a total of 386 and 164 house-day measurements or 18,528 and 7,872 30-min emission data points for the HR houses and the MB houses, respectively. The ER showed considerable diurnal and seasonal variations. The annual mean ERs (g NH3 hen-1 d-1) and standard errors were 0.90 ±0.027 for IA-HR houses with standard diet, 0.81 ±0.02 for IA-HR houses with a nutritionally balanced 1% lower crude protein diet, 0.83 ±0.070 for PA-HR houses with standard diet, 0.054 ±0.0035 for IA-MB houses with daily manure removal, and 0.094 ±0.006 for PA-MB houses with twice a week manure removal. Mass balance of nitrogen (N) intake and output performed for IA-HR houses revealed a total N intake recovery of 94% to 101%, further verifying the certainty of the NH3 ER measurements. Results of the study contribute to the U.S. national inventory on NH3 emissions from animal feeding operations, particularly laying hen facilities as affected by housing type, manure handling scheme, crude protein content of the diet, and geographical location.

Ammonia Emissions from Twelve U.S. Broiler Chicken Houses

Twelve commercial broiler houses in the U.S. were each monitored for at least thirteen 48 h periods over the course of one year to obtain ammonia emission data. Paired repetition of houses on four farms represents current construction with variety in litter management (built-up or new litter each flock) and climate conditions (cold or mixed-humid). Ammonia concentration was determined using portable electrochemical sensors incorporating a fresh air purge cycle. Ventilation rate was determined via in-situ measurement of fan capacity, fan on-off times, and house static pressure difference. There were seasonal trends in exhaust ammonia concentration (highest in cold weather) and ventilation rates (highest in warm weather) but not for emission rate. Flocks with at least three monitoring periods (13 of 22 flocks) demonstrated similar emission rates at a given bird age among the four study farms and across the seasons. An analysis of emissions from all houses on the three farms using built-up litter resulted in predicted regression slopes of 0.028, 0.034, and 0.038 g NH3 bird-1 d-1 per day of age; the fourth farm, managed with new litter, had the lowest emission rate at 0.024 g NH3 bird-1 d-1. The intercept of these composite relationships was influenced by litter conditions, with flocks on new litter having essentially no emissions for about six days while built-up litter flocks had emissions starting at flock placement. Data from all four farms and all flocks provided a regression slope of 0.031(±0.001 std error) g NH3 bird-1 d-1 per day of age. Emission rate per animal unit for built-up litter flocks indicated very high emissions for the youngest birds (under 14 days of age), after which time the emissions decreased exponentially and were then relatively steady for the balance of the flock cycle.

AIR QUALITY AND EMISSIONS FROM LIVESTOCK AND POULTRY PRODUCTION/WASTE MANAGEMENT SYSTEMS

The objective of this paper is to summarize the available literature on the concentrations and emissions of odor, ammonia, nitrous oxide, hydrogen sulfide, methane, non-methane volatile organic carbon, dust, and microbial and endotoxin aerosols from livestock and poultry buildings and manure management systems (storage and treatment units). Animal production operations are a source of numerous airborne contaminants including gases, odor, dust, and microorganisms. Gases and odors are generated from livestock and poultry manure decomposition (1) shortly after it is produced, (2) during storage and treatment, and (3) during land application. Particulate matter and dust are primarily composed of feed and animal matter including hair, feathers, and feces. Microorganisms that populate the gastro-intestinal systems of animals are present in freshly excreted manure. Other types of microorganisms colonize the manure during the storage and treatment processes. The generation rates of odor, manure gases, microorganisms, particulates, and other constituents vary with weather, time, species, housing, manure handling system, feed type, and management system. Therefore, predicting the concentrations and emissions of these constituents is extremely difficult. Numerous control strategies are being investigated to reduce the generation of airborne materials. However, airborne contaminants will continue to be generated from livestock and poultry operations even when best management systems and/or mitigation techniques are employed. Livestock and poultry buildings may contain concentrations of contaminants that negatively affect human and animal health. Most of these health concerns are associated with chronic or longterm exposure to gases, dust, or microorganisms. However, acute or short-term exposures to high concentrations of certain constituents can also have a negative effect on both human and animal health. For example, the agitation and pumping of liquid manure inside a livestock building can generate concentrations of hydrogen sulfide that are lethal to humans and animals. Once airborne contaminants are generated they can be emitted from the sources (building, manure storage, manure treatment unit, or cropland) through ventilation systems or by natural (weather) forces. The quantification of emissions or emission rates for gases, odor, dust, and microorganisms from both point sources (buildings) and area sources (beef and dairy cattle feedlot surfaces, manure storage and treatment units and manure applied on cropland) is being intensely researched in the U.S., in many European countries, Japan, and Australia. However, the accurate quantification of emissions is difficult since so many factors (time of year and day, temperature, humidity, wind speed, solar intensity and other weather conditions, ventilation rates, housing type, manure properties or characteristics, and animal species, stocking density, and age) are involved in the generation and dispersion of airborne materials. Furthermore, there are no standardized methods for the collection, measurement and calculation of such constituents, resulting in significant variability and large ranges in the published literature. In fact, emission rates of only a few airborne contaminants have been investigated. Ammonia, hydrogen sulfide, and methane emissions have been more thoroughly studied than other gases and compounds because of the negative environmental impacts or human health concerns associated with them. Unfortunately, there is very little emission data for other contaminants such as odor, nitrous oxide, non-methane volatile organic compounds, dust, and endotoxins. The long-term impacts of these constituents on the environment and on human health are also not known.

A Portable System for Continuous Ammonia Measurement in the Field

A portable and relatively low-cost monitoring unit (PMU) for continuous measurement of ammonia and carbon dioxide in CAFO (poultry in particular) applications has been developed and partially compared with an EPA-approved measurement method. The PMU utilizes sampling and purging cycles to overcome the sensor saturation characteristic of electro-chemical NH3 sensors. Preliminary comparative results show that performance of the PMU is quite comparable to the sophisticated, highercost, and less portable mobile lab method. For the range of ammonia level typical of commercial poultry buildings, the PMU is expected to produce emission rate data of reasonable quality when combined with properly measured or determined building ventilation rate.

Daily, monthly, seasonal, and annual ammonia emissions from Southern High Plains cattle feedyards.

Ammonia emitted from beef cattle feedyards adds excess reactive N to the environment, contributes to degraded air quality as a precursor to secondary particulate matter, and represents a significant loss of N from beef cattle feedyards. We used open path laser spectroscopy and an inverse dispersion model to quantify daily, monthly, seasonal, and annual NH emissions during 2 yr from two commercial cattle feedyards in the Panhandle High Plains of Texas. Annual patterns of NH fluxes correlated with air temperature, with the greatest fluxes (>100 kg ha d) during the summer and the lowest fluxes (<15 kg ha d) during the winter. Mean monthly per capita emission rate (PCER) of NH-N at one feedyard ranged from 31 g NH-N head d (January) to 207 g NH-N head d (October), when increased dietary crude protein from wet distillers grains elevated emissions. Ammonia N emissions at the other feedyard ranged from 36 g NH-N head d (January) to 121 g NH-N head d (September). Monthly fractional NH-N loss ranged from a low of 19 to 24% to a high of 80 to 85% of fed N at the two feedyards. Seasonal PCER at the two feedyards averaged 60 to 71 g NH-N head d during winter and 103 to 158 g NH-N head d during summer. Annually, PCER was 115 and 80 g NH-N head d at the two feedyards, which represented 59 and 52% of N fed to the cattle. Detailed studies are needed to determine the effect of management and environmental variables such as diet, temperature, precipitation, and manure water content on NH emissions.

EFFECT OF WIND TUNNEL AIR VELOCITY ON VOC FLUX FROM STANDARD SOLUTIONS AND CAFO MANURE/WASTEWATER

Researchers and practitioners have used wind tunnels and flux chambers to quantify the flux of volatile organic compounds (VOCs), ammonia, and hydrogen sulfide and estimate emission factors from animal feeding operations (AFOs) without accounting for effects of air velocity or sweep air flow rate. Laboratory experiments were conducted using a small rectangular wind tunnel (30.5 cm length, 15.2 cm width, 5.1 cm height). The objectives of the research were to (1) quantify the effect of wind velocity on VOC flux rates, (2) compare and contrast a two-film model with different wind speed corrections, and (3) provide insight into methods for either selecting appropriate wind tunnel velocities or conducting post-sampling wind velocity corrections to simulate field emission rates. Fluxes were measured on standard solutions and on manure/wastewater from beef cattle and dairy AFOs. Volumetric air exchange rates were varied between 0.6 and 44 exchanges per minute, corresponding to calculated longitudinal air velocities of 0.003 to 0.23 m s-1. Exhaust air was sampled using stainless steel sorbent tubes and analyzed for eleven volatile organic compounds comprised of seven volatile fatty acids (VFAs: acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic) and four heavier molecular weight semivolatile organic compounds (sVOCs: phenol, p-cresol, indole, and skatole) using gas chromatography/mass spectrometry. Sulfur-containing VOCs were quantified using a portable total reduced sulfur meter. Flux rates for VOCs with small dimensionless Henrys law constants (i.e., those found at AFOs) increased with increasing air velocity. The two-film model with an experimentally derived reference gas-film transfer coefficient was found to reliably predict VOC flux at velocities between 0.003 and 0.23 m s-1. However, the two-film model did not reliably predict VOC flux with other air velocity correction formulae, an indication that flux is a function of wind tunnel geometry and turbulence factors, and not just average air velocity or sweep air flow rate. These results corroborate other studies that show that air velocity is a major factor affecting VOC fluxes from AFOs, verifying that an air velocity correction factor is required for estimating accurate VOC emission factors using wind tunnels and flux chambers.

Microbiological status of piggery effluent from 13 piggeries in the south east Queensland region of Australia

Aims:  To assist in the development of safe piggery effluent re‐use guidelines by determining the level of selected pathogens and indicator organisms in the effluent ponds of 13 south‐east Queensland piggeries.

The National Air Emissions Monitoring Study: Overview of Barn Sources

The National Air Emissions Monitoring Study (NAEMS) is required by a U.S. EPA air consent agreement, in which livestock producers agreed to collect air emission data in exchange for more time to report their emissions and apply for any necessary permits. Field measurement of livestock air emissions is a major part of the study. Compared with most previous field studies of barn air quality, the NAEMS was designed to have 1) several pollutants measured simultaneously including particulate matter (PM), ammonia (NH3), hydrogen sulfide (H2S), and non-methane volatile organic compounds (NMVOC), 2) a long duration of two years, 3) a large number of measured barns (38) using the same protocol, 4) careful selection of farms to enhance their representativeness, and 5) a high level of quality assurance and quality control as required by the U.S. EPA, which is supervising the study. The NAEMS is collecting continuous air emission data from 38 barns at five dairies, five pork production sites, three egg layer operations, one layer manure shed, and one broiler facility for a period of 2 years starting in 2007. At each barn monitoring site, an on-farm instrumentation shelter houses equipment for measuring pollutant concentrations at representative barn air inlets and outlets, barn airflows, operational processes, and environmental variables. A multipoint gas sampling system delivers selected air streams to gas analyzers. Mass PM concentrations are measured at one representative exhaust location per barn using real-time monitors. Motion sensors monitor activity of animals, workers and vehicles. Building ventilation rate is assessed by monitoring fan operation and building static pressure in mechanically ventilated barns, and air velocities through ventilation openings in naturally-ventilated buildings. Data is logged every 15 and 60 s and retrieved with network-connected PCs, formatted, validated, processed, and delivered to the U.S. Environmental Protection Agency (EPA).

Field Estimation of Ventilation Capacity Using FANS

Instrumentation and procedures have been developed to characterize mechanical ventilation system capacity as part of an evaluation of ammonia emissions from commercial poultry housing. A FANS anemometer array unit, developed at the Mississippi USDA center, built and refined at University of Kentucky, and calibrated at the BESS laboratory, was found to have repeatability in the range of about 1% between two traverse readings performed one after the other. The unit was used to measure broiler house fans under typical system static pressure differences. A hydraulic lift cart was fabricated to streamline FANS positioning and movement through the large poultry houses. Taping all gaps between the FANS unit and fan housing improved airflow measurements about 6% versus not taping. Using a duct to transition down to 36-inch fans resulted in a 2.5% improvement versus not using a duct. Fan manufacturer performance data was 2 to 13% higher than actual field performance.