Ammonia emission model for high-rise layer houses
Ammonia (NH3) production from livestock facilities, especially poultry units, in the U.S. has raised serious environmental concerns with the public because of its impact on the environment due to potential water, soil and air pollution. Accurate estimations of NH3 emission rate from individual operations is important and is a challenging task for regulatory agencies and farm producers. The National Air Emission Monitoring Study (NAEMS) provided the egg industry with two years of quality-assured field data for NH3, H2S, CO2, and PM emissions from six high-rise layer houses, two manure belt houses and a manure shed. The objective of this dissertation was to review the factors affecting NH3 emission from the high-rise houses, improve data completeness, and develop statistical and mechanistic ammonia emission models for these types of houses based on the refined NAEMS data. The statistical regression model used exhaust temperature, live mass density, hen age and manure accumulation time as inputs to provide reasonable estimates of NH3 emissions. The mechanistic model consisted of flock, environmental, and manure sub-models to estimate inventory, hen weight, hen activity, ventilation rate, and ammonia emission rate. Tests of three Indiana layer houses conducted prior to the NAEMS were used to verify the statistical and mechanistic NH3 emission models. Based on comparison with measured data at a total of nine houses, the mechanistic model demonstrated less bias and more accurate NH3 estimation than the statistical model.
Heber, Purdue University.
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