The Crave Brothers run a dairy farm with cheese production in America. They are particularly concerned about keeping the ecological footprint as small as possible. In 2007, they initiated a turnaround: On the one hand, the 3,400 cows on the farm produce an enormous amount of liquid manure. On the other hand, the cow farm and the cheese dairy require a lot of energy. In order to solve both problems with one solution, the decision was made for a liquid manure fermentation concept. The liquid manure is now fermented in their own biogas plant to generate energy.

Slurry fermentation - biogas as the key to success 

The family business had two stainless steel fermenters built, each with approx. 2,800m³ slurry. The resulting methane gas drives a generator to produce electricity. The energy is sufficient for the entire dairy farm and the cheese factory. In addition, another 300 households from the neighbourhood are supplied with the renewable energy. The fermentation process ends with two outputs. First, a very efficient liquid fertiliser is left over, which provides the young plants with high-quality nutrients. Secondly solids remain. These are also given back into the material cycle and serve as comfortable bedding material for the cows. A positive side-effect of this concept: the odour pollution of the farm has been considerably improved by liquid manure fermentation, as only a fraction of the odour emissions is caused by the fermentation residues. This means that the family business is sustainably positioned for the future. 

The family presents their farm on Youtube.

Location:

Wisconsin, USA

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