The Odor Emissions from Confined Animal Feeding Operations

Abstract

Over the years, the agricultural community and large-scale livestock productions have changed significantly. The trends include an overall reduction in the number of farms, but an increase in intensive livestock production facilities, which is a major source of odor in the rural communities. Odor nuisance and pollutant gas emissions continue to be a major issue for the livestock and poultry industries because of their potential environmental and health effects on animals, workers, and people who live nearby confined animal feeding operations (CAFOs). Odors from CAFOs are produced primarily via an incomplete fermentation, odorous compounds resulting from the anaerobic decomposition of livestock manure by bacteria, spilled feed, bedding materials, and wash water. The organic matter in livestock manure is microbially transformed into non-odorous end products under aerobic conditions.  Offensive odors are the problem that can lead to public opposition of existing CAFOs or establishing a new CAFOs or expanding an existing CAFOs. In rural areas, odor emissions from livestock operations constitute a major issue. Pollutants, such as NH₃, H₂S, particulate matter, odor, and pathogens emitted by animal production units represent risks to the health and well-being of animals, workers, neighbors, and to the global environment. Odor must first be quantified to determine odor emission values. Air samples are diluted with a known amount of odor-free air. The dilutions are presented to a specially trained panel of test personnel using an olfactometer, which is an air dilution device. There should be at least eight panel members for each odor measurement panel and they should have some special charactristics.

The objective of this study is to explain odor resources, formation mechanisms, measurement methods, and emissions from animal barns, dispersion models which were used in various countries for odor emission from barns to atmosphere, and also provide information about odor studies in different countries.