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Harnessing the Power of Pig Manure

by 5m Editor
16 February 2009, at 11:13am

US - A farmer has found great value in harnessing pig manure.

Long before President Barack Obama promised the country that "we will harness the sun and the winds and the soil," pig farmer, Danny Kluthe, already had yoked the power of pig manure, reports Lexington Herald Leader.

Manure from his hogs drains as a slurry into a giant vat. It is stirred and warmed. A virtually odourless liquid — ideal for fertilizing surrounding fields that, in turn, feed more pigs — emerges from the giant digester.

The real beauty, though, comes in the methane fumes that rise off the muck. They are funneled to a tractor engine and used to power a generator. Suddenly, his electrical utility is writing checks to him.

"There will be a day when there will not be a hog facility or a dairy built without one of these things," Mr Kluthe said. "This," he said with the glee of someone who has figured out how to spin straw into gold, "just makes too much sense."

What helps save the farm could help save the planet.

Because Mr Kluthe does not let the methane from hog waste waft away, his sewage lagoons pack just five per cent of the climate-changing punch they would otherwise.

In fact, his dung-to-dollars system is but one way agriculture can put food on your plate while dumping less greenhouse gas into Earth's atmosphere.

Other fixes can be made earlier in the process: improving grassland diversity, spreading fertilizer more precisely and tweaking animal feed.

Agriculture accounts for just six per cent of greenhouse gases (GHG) in the United States, but it is responsible for more than half the methane and nitrous oxide emissions. Molecule for molecule among greenhouse gases, methane has about 21 times the impact as carbon dioxide. Nitrous oxide is 300 times as powerful.

They might be some of the easiest to cut back, however.

"There's a lot of opportunity for agriculture to get this low-hanging fruit," said Evan Branosky, a research analyst at the World Resources Institute, an environmental think tank. "You can do some simple practices that are going to result in large reductions."

Better farming practices are part of the Regional Greenhouse Gas Initiative, a new carbon-trading market among ten north-eastern states that requires power plants to offset their carbon dioxide emissions.

Those sorts of carbon credits – in which a polluter in one part of the economy balances out its damage by paying others to cut back on their greenhouse gases – could provide an incentive to pay for greener farms.

Ranchers and feedlots already have plenty of enticement to fatten cattle as quickly as possible, but the ideal feed is not always the most economical. And low-impact tilling and chemical treatments do not always fill the most bushels at harvest.

Likewise, anaerobic digesters, such as the one Mr Kluthe runs to transform effluent into energy, are not built unless a government grant is involved.

Indeed, even as analysts see great hope for cutting back on greenhouse gases from farming, they emphasize that there are no universal fixes.

"It's important not to make blanket statements," Karin Wittenberg of Canada's National Center for Livestock and the Environment told Lexington Herald Leader. "There are a lot of factors to weigh."