Extended Abstract (184K)7.1
Atmospheric Dispersion of Odors and Gases from Animal Wastes
O. T. Denmead, CSIRO Land and Water, Canberra, Australia
The rapid development of intensive livestock production systems using confined rearing methods, often close to residential areas, is causing severe environmental problems through the creation of concentrated sources of malodorous animal wastes. Odor problems arise again when the wastes are disposed of by application to agricultural fields. While the principal concern of this overview is linking emissions and atmospheric concentrations of odors and gases from point, line, areal and small 3-dimensional sources, it sidesteps what is perhaps the main problem in the area: how to quantify odor intensity. It assumes that the concentrations of odorous gases can be measured directly or estimated from the concentrations of some tracer gas dispersing with them. Usually, however, olfactory response is subjective and is due to a mixture of compounds including NH3, H2S and >100 volatile organic compounds. Setting of air quality standards by regulatory authorities, prediction of odor dispersion and attempts to mitigate odor emissions all require objective measurements of odor intensity. Much work is now under way on this topic. Micrometeorological methods appropriate for studying dispersion from animal wastes in various contexts will be illustrated and discussed. Situations examined include lagoons, manure piles, small feed lots, strip-grazed pastures and fields irrigated with effluent.
Session 7, Lecture
Tuesday, 29 October 2002, 4:00 PM-5:00 PM