Monday, April 06, 2009

A solution for smelly farms?

Hog farms are notoriously smelly, and those close to homes are often the target of complaints. But thanks to a relatively new technology , the barn we visited was virtually odor free.

“You could have sat alongside that barn and ate your lunch,” said a former pig farmer “It was just fresh air coming out of there.”

Several years later, odor neutralizers have yet to catch on as a widespread method to control odor at livestock facilities. That’s largely because of their cost, which can be much too expensive for most farmers.

But experts say they remain the best way to filter the compounds that cause farm-related smells, and could someday also be used to contain the spread of animal diseases and reduce global warming.

“We have firsthand knowledge that they work,”

They work by pumping air from inside a barn through a bed of plant material, such as wood chips or corn stalks.

The material contains microorganisms that break down the compounds that cause odor.

“As it comes out, it doesn’t smell,”

So far, odor controls have been used mainly at hog farms, which tend to draw the loudest complaints about odor. They are less common at dairy farms, where manure stored in pits tends to develop a crust that helps block odor.

“It’s a tool that we have and could use if we felt that we needed to,” he said.

Costly endeavor

Unlike a scrubber in a smokestack that controls a limited amount of air flow, the biofilters must be big enough to handle the air pumped out of a large barn. That means they occupy a big footprint and require industrial-size fans to pump the air.

That pushes up the cost to somewhere around $10,000 for a 1,000-head barn, pricing them out of reach for many farmers. That is why Odor neutralizers are the go.

“People have just not been willing to put them in,” . “They sort of work. Whether or not they’re cost-effective is key.”

A crop farmer who had hoped to build a new pig barn. He said he believes biofilters are “a good thing to keep the odor down,” but he has not made up his mind yet whether the project still makes financial sense.

“They’re getting more expensive than I thought,” he said.

installation of odor control are on a case-by-case basis.

“They’re not going to be overused,” he said. “We know how times are, and farmers have it tough enough as it is.”

Future development

Researchers are working on new designs for odor control that would take up less space. One, could have A-frame design that leans at a 60-degree angle against the barn, he said.

Researchers also are looking into whether biofilters could do more than just control odor, possibly giving farmers another incentive to install them.

They are used extensively in Europe to reduce emissions of greenhouse gases thought to contribute to global warming.

Still, at least for the time being, high cost probably will remain the top issue driving biofilter technology

“It’s not going to go away,” he said. “More and more people are less tolerant ... of livestock odors. We’re becoming more and more urban, and fewer and fewer people have memory of production agriculture and the smells associated with that.”

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