Biofiltration can reduce odor and hydrogen sulfide (H2S) emissions by as much as 95% and ammonia by 65%, according to South Dakota State University Extension Farm Safety and Machinery Specialist Dick Nicolai.
Nicolai says a biofilter is simply a layer of organic material, typically a mixture of compost and wood chips, that supports a population of microbes. Odorous air is forced through this material and is converted by the microbes to carbon dioxide and water.
A new publication from South Dakota State University Cooperative Extension tells how biofilters can reduce odor from livestock and poultry facilities. Fact sheet 925-C, "Biofilters," is available online at: http://agbiopubs.sdstate.edu/articles/FS925-C.pdf.
The eight-page publication provides tips on biofilter design, configuration, sizing, fan selection, moisture control, temperature, design considerations on naturally ventilated buildings, and construction. It also discusses costs, maintenance, and health and safety concerns.