Other manure management technologies and strategies have been or are being considered (e.g., Burton, 1997; Miner et al., 2000) and an extensive research program is under way. Many of these have been applied in municipal and industrial settings (e.g., Crites and Tchobanogolous, 1998). On July 25, 2000, Smithfield Foods, Inc., entered into a voluntary agreement with the Attorney General of the State of North Carolina to provide resources to be used in an effort to develop innovative technologies for the treatment and management of swine wastes that are determined to be technically, operationally, and economically feasible (Williams, 2001). Performance standards require comprehensive analyses of odor and ammonia emissions, pathogens, and economics for each technology. Currently, 18 technologies or systems are being studied.
Other technologies and practices such as livestock housing design and operation affect air emissions. A considerable research and development effort has been devoted to evaluation of inexpensive filters for exhaust air from buildings and of “windbreak walls” to deflect and disperse the exhaust airstream from buildings. Land application methods to decrease emissions are also being studied.
In summary, many options of varying cost and effectiveness are being evaluated for reducing emissions and managing manure on livestock and poultry farms. Measurement of air emissions from existing and alternative systems on commercial farms is needed for both emissions of local concern and those of regional and national concern.
The structure and management practices of the animal feeding sector respond mainly to economic dictates as influenced by government regulations. Both economic factors and regulations affecting this sector change as understanding of their effects and the effects of responses to them also change. This chapter provides what amounts to a recent snapshot of the sector’s structure and operations. While the exact direction of changes in economic factors and regulations, and thus the future structure and operation of the industry, may not be predictable, users of this report should expect change to occur.