Odor Team Tackles a Difficult Issue
The livestock industry is undergoing major changes in Minnesota as it is in many areas of the United States. Production units are increasing in size and parts of the industry are becoming more integrated. The rapid changes have lead to disagreement and controversy in many areas of the state. While the overall problem is complex, a department team comprised of faculty, staff, and students is attempting to find solutions to one of the most volatile issues--odor.
Who's Who on the BAE Odor Team
Odor Measurement
An important first step is odor measurement. Odors that are highly offensive to one person may be barely perceptible to another. Instruments that measure concentrations of gases identified with odors often do not accurately reflect what humans find objectionable. We have established a lab that uses olfactometry to assess odor from various samples. Dick Nicolai (BAE 1965; MS 1970) leads this effort. Trained panelists sniff gas samples from various manure sources and determine characteristics such as dilution threshold, recognition threshold, intensity, and persistence. Over 60 trained panelists including students and staff as well as outside individuals participate in this process. We are cooperating with an olfactometry laboratory at Iowa State University to develop and verify procedures.
Undergraduates Vicki Larson and Jeremy Tims gather data in the olfactometry lab.
Manure Storage Covers
The efforts at odor measurement are designed to help determine what's working, what isn't, and the success of alternatives to improve the situation. One approach is to add covers to manure storages to reduce volatilization of potential odor producing gases. Research is underway on laboratory scale systems led by Chuck Clanton (PhD 1985) and field scale systems led by Larry Jacobson (BAE 1972, MS 1974, PhD 1983). They are evaluating straw, oil, and several types of membrane materials.
Undergraduate Phil Marquardt takes an odor sample from a tank in the cover project.
Treatment Systems
Processing the manure or gases that are produced is another approach to reducing odors that is under study. Phil Goodrich is working with an entrepreneur on a tertiary oxygen activated sludge treatment system (TOASTTM) to address the problem. The system, involving anaerobic and aerobic reactors, and a liquid/solids separation unit, has successfully reduced odor and hydrogen sulfide emissions. Another effort led by Kevin Janni (BAE 1976) and Dick Nicolai uses biofilters to reduce odor and hydrogen sulfide gases in air exhausted from livestock buildings and manure storages.
Phil Goodrich and Roger Ruan are heading an investigation of using non-thermal plasma to treat exhaust gases in the laboratory and field. Hydroxyl ions and ozone react with hydrogen sulfide, ammonia, and odorous volatile organic compounds to produce oxidized compounds that are non-odorous.
Anrong Ning applies non-thermal plasma to an odor sample.
Odor Rating System
The information collected from various systems, coupled with dispersion modeling of gases from livestock operations, is being used to develop an odor rating system. The system will help decision makers evaluate the suitability of various sites for locating livestock facilities by factoring in species, type of building, probable wind direction and speed, management systems, and distances from neighbors. David Schmidt (MS 1992), Larry Jacobson, Dick Nicolai, and Jun Zhu are working on this project.
Other Research
Pit additives, dust control, and manipulation of animal diets are among the other factors that are being studied in an attempt to reduce odor emissions.
Funding and Impact
The research is supported by funds from the legislature, producer groups, equipment suppliers, lending agencies, and manufacturers of additives and covering materials.
The efforts of the team are starting to produce results which are being used in educational programs to help producers and others implement solutions. The educational efforts are focused in Minnesota, but the results are drawing national attention.
The School of Agriculture Endowed Chair in Agricultural Systems
Undergraduates Participate in Research
Page URL: http://www.bae.umn.edu/alumni/odor.html
Last updated December 9, 1997 by webmaster@gaia.bae.umn.edu
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