Create Electricity from Manure with a Methane Digester

Learn how a methane digester creates electricity from manure. Originally titled "NOW...Electricity from Manure Gases" in the May/June 1970 issue of Mother Earth News.


| May/June 1970



methane

This "floating" cover, which fits inside the 6-by-4-by-11 inch manure tank keeps the methane gas under pressure.


Photo by Mother Earth News staff

Reprinted with special permission from the May,1963 FARM JOURNAL,Inc. 

Make electricity front hog manure? You're kidding!

No, honest ... I've just visited a farm where they're doing it. The owner is Dr. George W. Groth, Jr., who maintains 1,000 hogs in confinement on his ranch in San Diego County, Calif.

They make the 10-kilowatt generator hum by capping a liquid manure pit — to trap the "sewer" gas — and tying it to a gas engine. "There's just about the right amount of electricity to pump our water and run the heat lamps for the baby pigs," says Dr. Groth.

As the system stands, Groth has right at $2,000 invested, including labor and the $800 he shelled out for a war-surplus generator. Converting the generator to "hog power" was simple. All it took was a natural gas carburetor plus a frill or two to increase efficiency.

For example, hot water from the engine's cooling system circulates through 300 feet of copper tubing coiled inside the liquid manure pit. It maintains a 90 to 100 degrees temperature in the pit. "You get maximum 'digestion' of the manure at that temperature," says Groth. A small pump which runs off the fan belt pulley circulates the radiator water.





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