Pork producers can benefit from substantial odor control on swine building pit fans using an engineering design that ensures a viable, effective biofilter.

“We have created a method for assembling a durable, rodent-resistant biofilter container that is built of readily obtainable materials using simple methods and tools,” says lead researcher Ted Funk, Extension specialist in agricultural engineering at the University of Illinois. Funk and Matt Robert, research engineer with the Department of Agricultural and Biological Engineering, have built two biofilters on the school’s research farm that they say have the ability to reduce odor emissions by up to 90%.

“The new design uses 30-in. concrete silo staves that fit together like puzzle pieces,” says Robert. “A hoop around the outside holds the staves together. The flooring is constructed of wood pallets or poultry flooring, and held up by 8-in. concrete blocks.”

A geotextile fabric is laid over the flooring to keep the biofilter media in place and still provide adequate airflow. Then the structure is filled with 2-3 ft. of media, comprised of wood chips and compost

Funk says the ductwork for the biofilter can be made from 10-ml. black polyethylene, the heaviest black plastic sheet available. A heat gun is used to weld the polyethylene into a 24-in.-diameter tube that is attached to the fan. A cable is trapped inside the tubing so it can be suspended from T-posts, thus protecting it from severe weather.

With components in place, a ventilation fan will blow air from the livestock facility into the plenum under the floor of the structure. Air seeps up through the biofilter media and biofiltration occurs.

“When you keep the biofilter media moist, you get a bacterial film growing on the outside of those particles,” reports Funk. “The gases are adsorbed into that moist biofilm and the bacteria go to work on them. They’re degraded into something that has no odor — carbon dioxide and water — so the odor from the facility is reduced between 80-90%.”

One of the greatest benefits of the new biofilter is that it can be constructed by livestock producers using materials that are readily available, at a low cost.

“Reducing odor and being a good neighbor sound good until it comes to the pocketbook,” says Funk. “Biofiltration has been around a long time in other industries, but it’s never been brought down to a cost that the livestock industry can handle.”

One biofilter structure is circular and the second is ellipitical to provide an opportunity for producers who might have to fit this into a narrower footprint, closer to a building, says Funk.

Work is ongoing on three other facets of the project:

1. Biofilter media characterization. Eleven media products have been tested, from chipped wood and compost to activated carbon and topsoil. Tests have refined the design to work for any media chosen by the producer.

2. Ammonia removal efficiency. Researchers are studying the effectiveness of biofilter bacteria in removing ammonia from ventilated air.

3. Biofilter moisture management system. Researchers have developed a novel, low-cost moisture sensor to continually measure moisture within the biofilter.

Researchers: Ted Funk and Matt Robert, University of Illinois. For more information, contact Funk by phone (217) 333-9313, fax (217) 244-0323 or e-mail funkt@illinois.edu.