Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
9/19/00
Contacts:
Terry Steinhart, Keokuk County Extension, (515) 622-2680,
tsteinha@iastate.edu
Sherry Hoyer, Iowa Pork Industry Center, (515) 294-4496,
shoyer@iastate.edu
Biofilter Project Smells of Success
CEDAR RAPIDS, Iowa -- A project at the Kirkwood Swine Facility at Kirkwood Community College in Cedar Rapids is pleasing to the senses and that's just what Iowa State University (ISU) Extension livestock field specialist Terry Steinhart wanted. He and ISU Extension agricultural engineer Greg Brennemann designed a biofilter for the exhaust fans at the college's farrowing facility to decrease odors and blend in visually with the surroundings. The project, funded by the Iowa Pork Industry Center at ISU, has succeeded, Steinhart said.
"Because of its location on campus, this biofilter needs to be nice-looking and not have grass sprouting from it," Steinhart said. "It's a simple design with a plenum over the top that funnels exhaust air from the building pit through the material and out into the open."
The biofilter is made from a two foot by eight foot piece of plywood and 2x6 boards on end that are covered with quarter-inch mesh wire on the bottom. The building pit air is forced into the space below the mesh and through the biofilter material between the 2x6 boards. Steinhart said the wire mesh keeps the wood chip and compost material from falling into the area where the exhaust air enters the biofilter. The plenum acts like a chimney to push the conditioned air through the filter material.
"One problem is that it must be kept moist, because otherwise the bacteria goes dormant and isn't able to work on the odor coming into the material," Steinhart said. "However, you can also over water. If the material becomes anaerobic, the lack of oxygen essentially turns the compost back into manure."
The biofilter material currently includes wood chips, horse manure, sawdust, straw and cornstalks, although the mixture will vary according to what is available and how much moisture is contained within the biofilter material itself. The odor coming from the biofilter is very similar to that of soil after a rain, according to Steinhart.
Steinhart said he doesn't think there will be a problem with the material freezing in the winter, as long as the right moisture balance can be established. He also plans to add small red worms to the compost material to help provide consistency in the aerobic decomposing process.
Producers who are interested in learning more about this biofilter project are invited to the Kirkwood Farm on Tuesday, Sept. 26, from 1-3:30 p.m. The farm will undergo an odor assessment that morning as part of the National Pork Producers Council's On Farm Odor/Environmental Assistance Program, and that afternoon producers will be able to see what happens during this process. Steinhart also will show the biofilter and explain how and why it works. Eventually he and Brennemann will offer assistance to producers who would like to install such a system in their operations.
ml: isufarm
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