The Odor Issue - It's Our Responsibility

Livestock Update, August 1995

Allen Harper, Extension Swine Specialist

On a national level, the impact of hog farming on the environment has never been debated more vehemently. The well publicized rupture of a large hog farm lagoon in rain drenched Onslow County, North Carolina, simply added fuel to the fire. The controversy is not limited to large units. Iowa producers running 40 to 90 sows have found themselves battling nuisance suits in State Court (Pork 94, Nov. 1994, p. 44).

So what does this mean for us here in Virginia where the number of producers has declined and hog production growth has been stagnant? Do we avoid hog production growth to avoid the controversy? Actually, modest growth is needed to maintain critical numbers of producers and hogs to keep Virginia a viable hog producing state. Even the most vocal proponents of hog production growth in Virginia have never suggested that our growth should be near the pace of growth in North Carolina. But well planned, moderate growth offers new economic opportunity for farmers and rural communities in Virginia.

At county and regional planning meetings, hog odor seems to be at the heart of the debate. Producers and industry folks must continue to tell our side of the story. This includes operation under the Department of Environmental Quality with good environmental safeguards and application of excess swine waste nutrients within the guidelines of a technically correct nutrient management plan. However, we cannot afford a cavalier attitude about odor and environmental protection. We must continue to stand up for hog production, not just with words, but with good management as well.

Total elimination of odor is impossible. There are, however, a number of management factors that can have a significant impact on odor generation.

• Within economic limitations, new hog units should be located on sites that will generate minimal odor problems.

• Anaerobic lagoons need to be loaded to their designed liquid capacity for optimum manure breakdown and minimization of odors.

• New lagoons require 12 to 18 months for the development of a stable bacteria population for anaerobic digestion. Adding water to increase the working volume of new lagoons is recommended to avoid start-up odor problems.

• Odors will be intensified if lagoons are undersized and overloaded.

• Seasonal temperature changes associated with spring and fall can cause readjustment of lagoon contents, creating a temporary odor problem.

• Two stage lagoon systems may improve odor problems and provide higher quality, lower odor water for pit recharge, pit flush and irrigation systems.

• Loading wastes into lagoons on a regular and frequent basis will promote a stable digestion process and reduce odors. Large loading rates at a singe time will result in greater odor problems.

• Dead swine should be properly buried, incinerated or transported to a rendering unit as quickly as possible.

• Flooring and ventilation systems that allow hogs to stay clean, dry and comfortable will reduce odors emitted from buildings.

• Minimizing feed waste will reduce the quantity of organic matter and nutrients available to generate odor.

• Promptly cleaning and disposing of waste feed and manure buildups in swine facilities will reduce odor and fly problems.

• Make land applications of lagoon effluent or pit slurries during the morning hours on low humidity days to facilitate rapid drying of the material and less odor emission.

• When feasible with land application systems, incorporate or inject the material into the soil.

• If possible, select days for land application when the wind direction allows minimal odor detection by neighbors.

• In general, odors will be more intense on warm, overcast and(or) high humidity days.

There will continue to be substantial interest in odor reducing and odor masking agents. At this time very little controlled research information is available on these products. Furthermore, these products can be quite expensive. At this point, swine facility odor control involves proper site selection, proper building and waste facility design and proper swine and waste management practices. An additional reference listing of practical measures to control hog farm odors can be found in Pork 94 magazine, September, 1994 issue, page 24. The source of the listing is Dr. Jim Barker, Agricultural Engineer from N. C. State University

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