The Power of Cow Crap...

You hear a lot about converting meadow muffins into green energy. Carrie Cockburn of The Globe and Mail illustrates how it’s done. Take a look:

And TreeHugger breaks it down further:
1. BARN: Slurry of manure is washed and scraped from cow stalls into a series of sewage pipes that run under the barn. The manure is mixed with other food wastes.

2. DIGESTER: The slurry is heated to around 37 degrees and kept at that level for the five days needed for the microbes to decompose the cow dung. This process gives off methane gas, which bubbles through the slurry and is collected at the top.

3. DIESEL GENERATOR: The gas runs to the generator, where it is burned to produce electricity to power the digester and the farm, and to feed into the grid.

4. SOLIDS SEPARATOR: Leftover liquids are used as fertilizer and the solids are strained to make a material to be used as bedding for the cows.
No doubt, working at one of these facilities will land you on an episode of Dirty Jobs with Mike Rowe.
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Paige - July 29, 2008 10:54 AM

I just got back from Nicaragua, where I saw a much lower-tech version of this in action. It was just a concrete-lined hole in the ground, about four feet wide, six feet long and probably four feet deep. Outside of the rectangle was a circular opening with a lid, allowing access to the main area. And covering the whole thing was a big plastic sheet with a hose coming out, leading into the house.

So, to make it work, you first fill the thing with a bunch of manure. That starts decomposing and the plastic sheet starts blowing up into a bubble, because of the methane being released. Once you've got that bubble, you can turn on the valve in the pipe, located next to your stove, and then light your gas stove. To maintain, you add one bucket full of manure (in their case, mostly pig) every day, and it keeps going, just like a sourdough starter.

The woman showed us the flame she got, a very impressive one. She said it would be larger, but that she had just cooked lunch a few hours before. She said that by dinner, there would be more gas and the flame would be larger.

So this is very cool technology, whether you're putting it through a process to get electricity or just using it right next to your house to cook your food.

Michael - July 29, 2008 4:33 PM


Wouldn't this make your food taste funny?

Paige - July 29, 2008 11:16 PM

I don't know - I didn't eat anything prepared over this flame. I do know that it didn't smell like anything and that the people using it have very particular tastes, and wouldn't be likely to accept any change in taste in their traditional cuisine.

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