Fall 2002
Aeration helps reduce odor in two-stage lagoon system
Sherry Hoyer, Iowa Pork Industry Center
When Frank Hirschman and his son Don wanted information on how to reduce odor as they expanded their hog operation in southeastern Plymouth County from 200 sows to 2,500 sows, they went to town for answers. Their local town, Kingsley, used aeration in its municipal lagoon and that sparked an interest in using similar technology on their farm. After receiving a referral to International Industries, Inc. in Sioux City, the Hirschmans worked with company representative Don Frankel to learn more about the success of some existing aeration systems.
Frankel showed them some aeration systems that were successful at reducing lagoon odors, so they decided to try one. That was 4 years ago, and the Hirschmans continue to be pleased with the results. The system the Hirschmans use is providing them with good quality liquid to flush through shallow pits to help reduce odor and maintain high air quality inside and outside of the buildings. Specifically, the aeration of the lagoon results in a more earthy smell, not like that from a normal hog confinement. And the odor does not seem to travel as far.
Aerator on second-stage lagoon at sow facility.
The 2,500-sow operation uses a two-stage lagoon with aeration in each stage. Liquid from the second stage is either recycled to flush the pits in the hog buildings or applied with a traveling gun to alfalfa fields. The Hirschmans apply the effluent to the fields only on days when the wind speed is 5 miles an hour or less. Although some might consider a double aeration system too expensive, the Hirschmans said that after the initial cost of equipment and installation, the main ongoing expense is electricity and it is reasonable. The original cost was just under $17,000. Now, it costs approximately $3,800 a year for electricity (approximately 6.8 cents per pig).
To others who are concerned about odor, air quality, and being a good neighbor, Frank Hirschman said he definitely recommends this system. However, he cautions that others should make their own evaluation of costs and benefits and compare several aeration systems to select the one best suited to their circumstances.
Typically, objectionable odors and gases such as hydrogen sulfide (H2S) and ammonia (NH3) are produced by anaerobic microbes, which live in animal manure pits and lagoons when no oxygen is present in the liquid. When oxygen is present, however, a different population of microbes exists that produce odorless gases. So by introducing enough oxygen into the manure, it can be made aerobic, so that odorless gases are produced. Aeration is the treatment system that introduces the oxygen and allows aerobic microbes to survive and thrive. It is frequently used by cities and industries before releasing wastes into waterways. Aeration is not often used by producers because of the additional cost and because they cannot release the manure into waterways even if treated. |
