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Gas leak: Scientists tackle stench from hogs

Scientists are making progress taming hogs’ smell by attacking the source of the problem, namely the feed gobbled up by swine.
PIG
This pig is among the dozens being tested in Indiana for a greater good: reducing, or at least changing, the smell from hog farms. Michael Conroy / AP
/ Source: The Associated Press

When a west wind blows, Linda and Perry Trader’s southern Indiana home is bathed in the stench of a nearby hog farm — a stink so foul they often retreat indoors, abandoning their backyard and swimming pool.

It’s not the life the couple imagined when they moved to rural Spencer 18 years ago, only to have a hog farm go in years later a quarter-mile away.

“Sometimes, I can taste it, it’s that sickening. The air’s just heavy with it,” said Linda Trader. “We close the windows, run the air conditioner and stay inside.”

Relief could be on the horizon for the Traders and others fed up with the stink of the nation’s hog farms. Purdue University scientists are making progress taming hogs’ smell by attacking the source of the problem, namely the feed gobbled up by swine.

Their research is a response to growing pressure from federal regulators, environmentalists and rural residents sick of the stench.

Smell from ammonia, hydrogen sulfide
In a new complex near Purdue’s West Lafayette campus, they are experimenting with the porkers’ diet, plying them with feeds intended to make farms less offensive to neighbors and reduce possible air and water contaminants.

Early results are promising. Hogs fed experimental feeds produce excrement with significantly reduced levels of ammonia and hydrogen sulfide, both of which help give swine manure its offensive smell, said Brian Richert, an animal sciences professor.

“We know we can change the characteristic of the odor,” he said. “It will probably still have the same amount of odor, but it will smell more like a cattle facility than a swine facility. And that would make it more appealing to the neighbors.”

The Swine Environmental Research Building holds up to 720 hogs. Inside, sensors compare the emissions of hogs that are fed the new diets with those of swine in adjacent rooms being raised on traditional livestock feed.

Passing gas
Every four hours, plastic tubes mounted throughout the complex draw in air from rooms where squealing hogs jostle for position at feeding troughs. Air is also drawn from the manure pits beneath the grated rooms. The samples are piped to an air monitoring room, where equipment analyzes gases and keeps track of the hogs’ activity levels, including how much dust they kick up.

The ultimate goal of the research — which includes a panel that sniffs the pungent air samples — is hog feeds that produce excrement with lower amounts of ammonia, hydrogen sulfide and other pollutants without compromising animal growth, Richert said.

His team is experimenting with feeds to tone down the smells with mixes that contain between 5 percent and 7 percent fiber. They’re also working with a genetically modified corn not yet commercially available.

Controversial EPA deal with farms
A consent agreement reached early this year between the U.S. Environmental Protection Agency and the livestock industry calls for an intensive study of the air around the nation’s biggest farms.

About 130 companies that operate thousands of livestock farms have signed onto the consent agreement, agreeing to abide by clean air, hazardous waste and emergency reporting laws.

Companies signing the agreement also must pay a civil penalty ranging from about $200 to $100,000, depending on the size and number of farms they operate. Those fines would cover presumed violations, past and present, and fend off potential liability for years until the EPA issues its air standards.

Four environmental groups have challenged the agreement in the D.C. Court of Appeals, calling it a “sweetheart deal” that will give farms immunity from prosecution and delay federal regulation of the farms’ emissions for years.