http://online.wsj.com/articles/government-scientists-try-to-take-the-stink-out-of-pig-manure-1411093808 

Government Scientists Try to Take the Stink Out of Pig Manure

Efforts to Take the Stink Out of Manure Increase, but Some Say That's a Waste

By MARK PETERS  
Sept. 18, 2014 10:30 p.m. ET

 
PEORIA, Ill.  Terry Whitehead's lab here is stocked with glass boiling flasks, Bunsen burnersundefinedand cans of extra-strength air freshener.

The microbiologist for the U.S. Department of Agriculture works with pig manure in a quest for something that has largely eluded scientists and entrepreneurs: an affordable way to clear the air in farm country.

In a region where hogs can outnumber people, Mr. Whitehead's research is the ultimate icebreaker.

"First, you say, 'I work with manure,' and they say, 'What?' Then you say, 'Odor,' and they say, 'Thank God,' " says the lanky 57-year-old, who recently attended the North American Manure Expo in Missouri. ("It would be a real waste" to miss it, the event website says.)


Efforts to combat the acrid odor of swine manure, which typically is stored in giant pits, have increased as farms get bigger and suburbs creep closer. The smell can pit neighbor against neighbor, sparking complaints and court battles, not to mention environmental concerns.

Some of the research over the years has been criticized in Congress as pork-barrel spending, but farm funk remains a priority for the Agriculture Department.

An expert in bacteria that grow without oxygen, Mr. Whitehead has been researching swine manureundefinedbottles of which he keeps in his lab refrigeratorundefinedsince the mid-1990s.

He first experimented with an animal-feed additive to attack the smell but found more success with a brown powder made from the South American quebracho tree. He also has drawn on research at Michigan State University on borax, the white powder used in household cleaners.

In the world of barnyard smells, pig and chicken manure are considered top offendersundefinedmuch worse than the common cow pie. Pig-manure storage pits can produce hundreds of compounds, creating a nauseating stew of odors, from the sharp bite of ammonia to the rotten-eggs stink of hydrogen sulfide.

The big challenge is getting any additive to work on the scale of a modern hog farm. An adult pig generates about 1.2 gallons of dung a day, and a single barn in the Midwest can house thousands of animals. Storage pits can hold hundreds of thousands of gallons of decomposing manure waiting to be spread on fields for fertilizer.

"It is so potent that it takes a lot of product to make a difference," says Al Heber, professor of agricultural and biological engineering at Purdue University.

Bottles of hog manure slurry in an experiment conducted by U.S. Agriculture Department scientist Terry Whitehead. The one on the left is untreated. The darker one on the right has been treated with tannins to reduce odors. Mark Peters/The Wall Street Journal
Farmers say many vaunted products haven't worked. In the 1990s, agriculture giant Monsanto Co. tried developing a spray but gave up after disappointing early tests. In the early 2000s, Mr. Heber tested 35 additives marketed to reduce manure smell. Some lowered the levels of certain malodorous compounds, but none made much of a difference in tests by trained sniffers.

"I get a lot of calls from guys who have a technology that is going to fix all our problems," says Michael Formica, chief environmental counsel at the National Pork Producers Council. But few of the products are up to snuff.

Government scientists last decade found success treating cattle manure with thyme and oregano-plant oils, which also are used in mouthwash and throat lozenges. More recently, Agriculture Department researchers experimented with an enzyme extracted from soybean plants, doing tests in a wind tunnel.

Some think the projects reek of government waste. In 2009, Republican Sen. John McCain of Arizona took issue with a $1.7 million federal budget item for "pig odor research in Iowa," lumping it with other spending on a rodeo museum and wolf-breeding facilities that he considered unnecessary.

Across the Midwest, swine farmers typically are advised to plant trees around barns to prevent odor from traveling and keep neighbors from seeing a constant reminder that thousands of hogs live nearby. Other suggestions to earn good will include hosting a summer pig roast or giving out holiday hams.

Just outside Iowa City, Iowa, Randy Lackender faced concerns from neighbors about the odors emanating from his hog farm. The 58-year-old farmer doesn't understand why people raise such a stink. "We have always had smells on the farm," he says. "It is a fact of living in the country."

Mr. Lackender nonetheless installed special filters in his barns that use microorganisms to clean the air and tested an additive for his manure pits. The first approach proved overly complicated to maintain, while the other didn't work.

Then he was offered a free trial of a product called ManureMagic from a small Texas company. The "magic" is a patented technology that relies on microorganisms that interfere with the decomposition process and limit creation of the worst-smelling gases, the company says.

Mr. Lackender says his wife estimated that the stench decreased by about 75% in two weeks. "She has a very keen sense of smell," Mr. Lackender says. He says he now buys the product regularly.

Back in his lab, Mr. Whitehead says his use of tree tannins sprang from past research on the digestive systems of cattle and sheep.

He and colleague Michael Cotta, a USDA supervisory microbiologist, knew that cattle that ate the leaves of the quebracho tree experienced changes to the bacteria in their digestive systems. So the pair bought a tub of the tree's tannins from a leather-industry supplier and started to experiment. The scientists added the powder to bottles filled with manure from a nearby farm. They sampled gases regularly from the bottles using a syringe and found lower levels of those that contribute to odor.

Mr. Whitehead and his colleagues have patented their work and last year published the findings in the journal Applied Microbiology and Biotechnology. He says a manure-additive company and kitty-litter makers have expressed interest.

On a recent afternoon, Mr. Whitehead unscrewed a plastic bottle filled with the dark slurry of hog waste. A rank odor escaped and began to spread through his lab. He keeps air freshener on hand to prevent it from seeping down the hall.

Though he has been surrounded by the smell of swine manure for years, Mr. Whitehead says, "You never get used to it."

Write to Mark Peters at mark.peters@wsj.com