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Housing Studies Promise Emission Results

Researchers are finishing up gas, odor and dust emissions testing inside a variety of hog and poultry facilities.

Researchers are finishing up gas, odor and dust emissions testing inside a variety of hog and poultry facilities.

Teams of agricultural engineers in six states are involved in a 30-month, $2.15-million project funded by the U.S. Department of Agriculture (USDA) which will establish baseline gas, odor and dust emission rates from mechanically ventilated hog and poultry buildings, says project co-coordinator Larry Jacobson, professor and Extension agricultural engineer, University of Minnesota.

Jacobson says the goal is to obtain 15 months of actual emission data, which is to conclude spring 2004. He plans to present preliminary results of the project, “Aerial Pollutant Emissions from Confined Animal Buildings or APECAB,” at the annual summer meeting of the American Society of Agricultural Engineers, Aug. 1-4 in Ottawa, Ontario, Canada. Final results are expected later in '04.

State research leaders for the four swine sites include Jacobson; Steven Hoff and Dwaine Bundy, Iowa State University; Yuanhui Zhang, University of Illinois; and Jacek Koziel, Texas A&M University.

All groups are using the same state-of-the-art analyzers that are housed in a climate-controlled mobile laboratory designed by the research team. The lab is positioned between two buildings at a production site so data can be collected from each building. Air is pulled through heated Teflon tubing that runs from each barn, sometimes underground, to the analyzers inside the mobile labs.

Baseline emission data is being collected for odor, ammonia, hydrogen sulfide, carbon dioxide and particulate matter under 10 microns in size (PM10).

Gas, odor and dust concentrations are collected at the air inlets and outlets of the barn, explains Jacobson. Emission rates are calculated by multiplying the concentration differences at the inlets and outlets by the building's airflow rates.

Gas levels are sequentially measured every 10 minutes at roughly six different locations in the barns. Odor samples are collected in Tedlar bags and analyzed by olfactometry every two weeks using trained odor panels. Ventilation rate, static pressure, temperature, humidity and wind speed and direction are recorded every 60 seconds or less, says Jacobson.

The project will enable researchers to evaluate if season of the year, time of day, building design, animal growth cycles and building management impact emission rates.

Projects Outlined

Besides the four swine sites, there are two poultry sites. An egg layer operation in Indiana is led by project co-coordinator Albert Heber, Purdue University; the other, a broiler facility in North Carolina, is led by David Beasley and Gerald Baughman of North Carolina State University.

In Minnesota, Jacobson is collecting data from two, 600-head sow gestation barns on a farrow-to-wean farm. Manure is collected in pull-plug, shallow gutters, which are drained weekly and recharged with wastewater from the outside manure storage.

In Illinois, Zhang is sampling from two, 24-crate farrowing barns with pull-plug manure gutters without recharge. Manure from the farrowing barns drains to a deep pit under the adjacent breeding barn on the 2,400-sow, farrow-to-wean site.

In Texas, Koziel and his mentor John Sweeten are monitoring two, 1,000-head finishing barns with a pull-plug, gravity-flow manure system.

Koziel is also conducting tests to identify the most offensive odorous gases out of the hundreds that make up swine odor. This knowledge will lead to improved sampling methods for evaluation of odor control strategies.

In Iowa, Hoff and Bundy are testing two, 1,000-head finishers with 8-ft.-deep manure pits. To simulate the air exhausted from a hog building, it is important that sensors test near the exhaust fans, Hoff explains.

Additional Projects

In a related project using the same methodology, Heber just completed an 11-month monitoring effort and abatement tests at two swine finishers in Missouri with Purdue's second mobile lab. Manure gutters in the buildings were flushed with recycled lagoon effluent.

In a companion project, Hoff, in Iowa, is using a second mobile lab trailer to test for hydrogen sulfide and ammonia gas levels inside and outside a rural residence. The project is in central Iowa's Hamilton County, where neighbors are concerned about hog farms. The home is located 2,200 ft. from two, 4,000-head, deep-pit finishing barns.

From three months of testing, Hoff has found some surprising results. The only time that gas levels are detected at all near the residence is during the night when the residence is downwind. “During the night, the atmosphere is very stable and gases tend to hang closer to the ground,” he notes.

Secondly, ammonia levels are definitely a lot higher inside the home, and consistently higher inside than outside the home, with no correlation to outside gas levels, says Hoff. He speculates the only plausible reasons are the ammonia produced by the homeowner's cat (urine), ammonia found in household cleaners and possible backdrafting from the home's septic system. Hoff plans to resume this companion project next spring at a different residence in central Iowa to compare results.

“One of the things we are trying to do in the research community is collect enough information to determine if, in fact, there really is a health risk associated with living in the community with livestock operations nearby,” states Hoff.

So far, he says, it appears that hydrogen sulfide and ammonia in the community from buildings are not a threat to human health. Researchers need to redouble their efforts to find cost-effective ways for pork producers to reduce the impact of odor nuisances on a community, he adds.

Surveys Document Odor Control Efforts

Two surveys conducted by Iowa State University (ISU) show that pork producers are using a wide variety of means to control hog odors from their operations; 562 pork producers returned a mail survey and 354 producers participated in a telephone survey.

The mail survey asked whether producers were using, or had used, 24 different methods of odor control. The four most popular technologies were windbreaks, buildings with deep-pit manure storage, composting mortalities and injecting manure into the soil during field application as fertilizer.

Some technologies were well liked but not used by many producers. One example was manure storage covers made of straw or chopped corn stalks. These biocovers were used by 10% of the producers, with 70% producer satisfaction.

In the phone survey, producers were asked if they had received any odor complaints. Only a small percentage said they had, with more than half of those related to manure application on fields.

“Manure application is a key area for reducing odor complaints,” says Jeff Lorimor, ISU agricultural engineer. “This is something that is done only a few days each year, but it leads to many of the complaints. Producers need to use extra caution and care during manure application. More communication and coordination with neighbors on the timing of manure application may be helpful,” he adds.

There were only a few complaints due to production facilities or manure storage.

The full report is available at