Consulting agricultural engineer Terry Feldmann of Feldmann & Associates offers these top 10 siting tips to avoid odor problems:
1. Consider the direction of prevailing winds and wind speed when siting a facility. Wind direction frequency and speed records are kept at various weather stations by the National Weather Service and cooperating agencies.
These records will show the percentage of hours over the most recent 30-year period that the wind blows from each of 16 different directions/compass points (i.e., south-southwest, southwest, west-southwest, etc.) and the percentage of calm hours.
The records also indicate the average wind speed from each direction. Records are typically compiled on a monthly basis which helps evaluate the potential affect of seasonal increases in odors.
For example, odor potential from a treatment lagoon or other outside manure storage typically peaks in the spring during the turnover period.
Additionally, high wind speed over a liquid surface increases the emission rate of odors through physical "stripping" and increasing the concentration gradient.
2. Review temperature and net radiation data to help determine the season or month which has the largest potential for odor production.
Manure storage basins can absorb tremendous amounts of solar radiation. As air and manure liquid temperatures increase, so do the emission rates of volatile organic compounds (odor compounds). Generally speaking, odor potential is greatest in the spring and summer. This data should be correlated with the prevailing wind data.
3. Determine distances to residences and other places that people frequent such as businesses, schools, churches, recreational areas, etc.
Though many companies are quickly developing products and systems to reduce odors, some of the best tools are still dispersion, dilution and filtration. Many odor compounds settle out and others are dispersed and diluted over reasonable separation distances (1,000 ft. plus). Odor intensity, frequency and duration all decrease with increased separation distance.
4. Orient facilities so that their shortest axis (i.e., width) is perpendicular to the wind direction of most concern.
For example, if the size of your facility is 200 x 600 ft. and the wind direction of concern is from the south, orient your facility so that the east-west dimension is 200 ft. Odor plumes typically stay about as wide as their source.
Therefore, in the above example, you can orient the facility so that the odor plume is only about 200 ft. wide rather than 600 ft. wide.
5. Rate the landscape and topography of potential sites. Filtration, dilution and dispersion significantly affect odor transport. Some research indicates that over half of odorous compounds are transported via dust particles.
The topography and landscape (trees, vegetation, windbreaks, etc.) significantly influence odor transport potential.
6. Review the site topography for potential air drainage problems. On many summer days, the winds are calm during the evening hours.
The air at ground level cools first and therefore will travel downslope through the swale of a creek or river valley taking odors from around livestock facilities with it.
7. Determine if there are residences and other places frequented by people that are located downslope of the site.
Locate facilities on the most isolated site feasibly possible. The notion of "out of site, out of mind" is valid. If people have sensed odors one time, they will think they detect odor every time they make the visual link with the facility.
8. Evaluate the available manure application areas of a particular site. The manure application area is the largest single odor source because of the large surface area. Application odors can be minimized by injection and are typically of low frequency (once or twice per year), but must still be weighed significantly when it comes to choosing a site.
If most of the application area is located near a residence or other odor-sensitive area, consider an alternative or better site. The majority of odor complaints for livestock facilities are still from manure application.
9. Develop options for dead animal disposal for a site. Selecting a site where renderers will dependably pick up deads once a day is better than one where your best option is composting.
Composting can be relatively low odor but it does require management.
10. Consider whether or not the site is located in a traditional livestock production area. If livestock production is not new to an area, there will be less anxiety among your neighbors.
Terry Feldmann is a private agricultural engineering consultant based in East Peoria, IL. He can be reached by phone, (309) 699-6962; fax, (309) 699-6964; or e-mail, TLFeldmann@aol.com.