Methane digesters (or anaerobic manure digesters) convert manure into methane and use the biogas to produce energy, thus transforming waste into a valuable byproduct while reducing greenhouse gas emissions and farm odor.

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Methane Digester

Methane Digester

Location: Marshall, CA
Featuring: Albert Straus of Straus Family Creamery

Albert’s father started the farm in 1941. The two became partners in 1977, and by ’94 it became the first certified organic dairy and creamery west of the Mississippi.

1) Barn slurry, sileage runoff, and creamery waste flow into the slurry pit.
2) This mixture is pumped into a devise which separates the manure’s solids and liquids.
3) The liquid flows by gravity into the digester pond.
4) Anaerobic digestion = bacteria digests the waste and gives off methane gas
5) The methane gas fuels a generator that offsets the farm’s energy use by 90%.
6) Heat captured from the engine makes hot water used to wash equipment in the milking barn.

The digester tarp is made from polypropylene methane = a greenhouse gas produced by cow flatulence and defecation which pollutes the environment.

1) Saves money by generating 300,000 kilowatt hours of energy per year
2) Eliminates a greenhouse gas 23 times more damaging than CO2
3) Converts nitrogen into a more usable form for plants
4) Cuts down on the odor and flies around the farm

Ten cubic yards of manure solids are produced each day. These are hauled to another location, composted, then spread on fields as fertilizer.

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