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Project To Develop Manure Setback Guidelines

“It’s up to government to take it to the next level.”


How far away from a house should a barn be? For people who live near a pig farm, or any other type of livestock operation, the question isn’t an academic one. It’s very real.

Ask rural residents for their main concern about livestock operations and they’ll invariably answer: odour. Many a relationship has soured over complaints about the smell from barns containing farm animals. The perception (and sometimes the reality) is that the barns are too close to where people live.

Ideally, the solution should be an adequate setback distance between barns and residences.

But the method for estimating setbacks is usually empirical (based on experience) rather than dispersion (based on science). And experience clouded by emotion isn’t always the best teacher.

Now a team of University of Manitoba researchers hopes to develop a science-based dispersion model for calculating accurate and effective setbacks.

A two-year $96,000 project funded by the Manitoba Livestock Manure Management Initiative will come up with the model.

The project follows up on a 2008 Manitoba Clean Environment Commission recommendation that the province develop a dispersion-based odour guideline for setbacks.

Manitoba does have guidelines for setback distances but they’re empirical and overly simplified, said Qiang Zhang, a University of Manitoba biosystems engineer heading the project.

Three elements determine setbacks: odour emissions, how far they travel and people’s tolerance to them, said Zhang.

Previously, all three elements were lumped together in an experienced-based model. Zhang said his team will examine each element separately and quantify acceptable thresholds for each one.

The project hopes to develop two things: criteria for acceptable odour exposure and models to estimate odour emission rates. The result will be “a dispersion-based setback guideline,” according to a project outline.

The study will involve both hog and poultry facilities. Trained interviewers will talk to people living near these operations about odours and how they affect lifestyles.

Assessors will also go out and “sniff” odour emissions themselves at 10-second intervals for 10 minutes, resulting in 60 samples and producing one “odour hour.”

The collected data will go into a dispersion model used to develop the setback guidelines.

Zhang emphasized the guidelines will consider a range of factors: time of day, season, weather conditions, topography and type of operation. “It’s not one size fits all,” he said.

A final report is expected in December 2011.

Zhang said the model, when complete, can be plugged into a future plan for a livestock operation to see if it follows acceptable setbacks.

He said the model can be used in two ways. Producers can use it to prove they’re following acceptable setbacks. Or opponents can use it to show they’re not.

Either way, conflicts can be settled empirically and scientifically, not based on emotion, said Zhang.

Scientists only have to develop a workable model. It’s up to authorities to decide if and how to use it, he said. “It’s up to government to take it to the next level.” [email protected]

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