On a particularly warm spring day in St. Paul, the unsavory scent of animal manure wafts through the air. For those who could do without the smell of animal excrement, a statewide survey brings hope for a breath of fresh air.
A Minnesota Pollution Control Agency study explores ways of controlling odor emitted by manure storage systems.
“We protect human health and the environment,” said James Sullivan, author of the survey. “Odor from animal waste is something that affects peoples’ lives.”
The MPCA has mailed out more than 1,500 surveys to Minnesota dairy producers. The surveys include questions about animal nutrition, manure handling and manure storage structures.
The questions are focused on identifying the factors that control formation of an effective crust on the manure surface of facilities. The crust is a natural reducer of odor, eliminating up to 90 percent of the smell.
Currently, the MPCA enforces no restrictions on odor levels from animal waste emissions.
Sullivan had an early draft of his survey questions reviewed by University faculty, including Kevin Janni, professor of biosystems and agricultural engineering.
“The whole area of livestock odor control has really evolved in the last three years,” Janni said.
Janni and a group of biosystems and agricultural engineering faculty members are awaiting grant money for a state-approved research project that also investigates the effect of naturally forming crusts.
Richard Nicolai, research fellow for the Department of Biosystems and Agricultural Engineering, has done University research on other odor control techniques, including biofilters and artificial covers for manure storage facilities.
Nicolai, who will be working with Janni on the upcoming study, also has his own swine herd. He has recently implemented a biofilter on his farm, a system that uses tiny organisms found naturally in soil to oxidize gases released by the manure.
While such projects provide encouragement for the weak of nose, Sullivan admits that his survey does not guarantee answers.
“Maybe no trend will be discovered,” said Sullivan, who has already received several hundred completed survey forms. “But in thumbing through the results so far, it looks like there may be some patterns developing.”
The final data from the study will be shared with the University’s Department of Biosystems and Agricultural Engineering and the Extension Service.

Andy Skemp covers environment and transportation and welcomes comments at [email protected].