Anaerobic Digesters: Generating Power with Powerfully Smelly Stuff

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TheBioenergySite Latest News

Wednesday, March 19, 2008

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Anaerobic Digesters: Generating Power with Powerfully Smelly Stuff

US - With concerns about global warming and reducing our dependence on fossil fuels, we hear a lot about the search for renewable sources of energy.

What you may not know is that there’s a potential source of renewable energy right under our noses in Wisconsin…manure.

With the help of an anaerobic digester, farmers can generate heat and electricity using animal waste.

Gale Gordon, of Deer Ridge Dairy, part of Gordondale Farms in Nelsonville, owns what’s called a “mixed-plug flow” anaerobic digester.

It’s a kind of digester that’s been patented by a company called GHD, Inc. in Chilton.

This digester takes the manure and then uses anaerobic bacteria to break it down in a large chamber.

After about 22 days in the digester, out come a solid product, a liquid product, and what’s called biogas.

The biogas is sent to an engine which is hooked up to an electric generator; the electricity is sold to a utility company.

At Gordon’s farm, with more than eight hundred cows, he’s able to generate enough electricity to power 130 homes.

After the solid product comes out of the GHD digester, more than 99% of the harmful bacteria from the manure (like E-coli) have been killed; and the solid product is used as bedding for Gordon’s cows.

The liquid product is rich in nutrients, and is used as a crop fertilizer.

But the benefits don’t stop there…

Heat from the engine that burns the biogas is used to heat the dairy’s water and the floor of the milking parlor.

The solid and liquid product come out free of offensive odor and the biogas is burned, so the air around the farm is more pleasant to breathe.