Wendy J. Powers Iowa State University

Resources Authored

Factsheets

Science of Smell Part 3 : Measurement and Detection of Odors from Swine Operations

Publish Date: 11/27/2012

As perceived by humans, odors have five basic properties that can be quantified: 1) intensity, 2) degree of offensiveness, 3) character, 4) frequency, and 5) duration, all of which contribute to the neighbor’s attitude towards the odor as well as the pig production generating the odor. It is generally accepted that the extent of objection and reaction to odor by neighbors is highly variable. The reaction can be based on previous experience, relationship to the odor-producing enterprise and the sensitivity of the individual. Weather (temperature, humidity, wind direction) affects the volatility of compounds, preventing or enhancing movement into the gaseous phase where an odor can be dispersed downwind.


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Factsheets

Science of Smell Part 1 : Perception and Physiological Responses to Odors

Publish Date: 11/27/2012

Olfaction, the sense of smell, is the least understood of the five human senses. This, among other factors, makes the task of reducing livestock odors a considerable challenge. This factsheet explains the terminology used to describe odorants and odor, how the human olfactory system works, and how humans respond to odor.


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Factsheets

Science of Smell Part 2 : Understanding the Generation and Chemistry of Odors

Publish Date: 11/27/2012

Odor chemistry is complex and still poorly understood. More than 75 odorous compounds, in varying proportions, have been identified in livestock manures. Knowing the chemical basis of odors derived from animal manure is helpful to understand how odor develops and what can be done to design and manage manure systems and avoid nuisance complaints.


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Factsheets

Use of the Air Management Practices Assessment Tool for Decision-Making

Publish Date: 09/24/2007

Air quality issues continue to receive increasing attention at local, state and national levels. As a result, producers are under increasing pressure to find ways to reduce air emissions. Following completion of the EPA Air Consent Agreement we will have a better idea of how much an animal feeding operation (AFO) needs to reduce the emissions of a specific gas, if at all. At that time producers will need to know what options are available and how much of a reduction in emissions they can anticipate for the various options. It will be useful to producers as they consider options to have an idea of the relative cost of the various emission mitigation practices. An electronic decision aid for producers who want more information on management practices can assist in improving air quality from AFO has been developed*.


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Factsheets

Energy and Nutrient Recovery from Swine Manures

Publish Date: 06/03/2006

While the primary method of swine manure management in the United States is temporary storage followed by land application as crop fertilizer, there is increasing interest in recovering energy and nutrients from manures prior to land application. Insufficient nutrient assimilation capacity in nearby crop land, or interest in adding value to swine manure beyond the fertilizer value, are among the reasons that alternative management strategies may be sought. Producers who consider alternative manure uses will find many options available. This publication describes several energy and nutrient recovery processes currently available. Each process is explained and primary issues that a producer should consider with each process are discussed.


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