The principle of biogas production

The conversion of biomass to biogas in the tank (fermenter) with the help of microorganisms is called anaerobic fermentation. End product of this process is biogas - the mixture of methane, carbon dioxide and other components. It runs in four consecutive stages, referred to as::

  1. Hydrolysis - is carried out in an environment containing oxygen in the air.Organic polymers (polysaccharides, lipids, proteins) with the help of anaerobic bacteria decompose into monomers (alcohol and a fatty acid) to release the hydrogen and carbon dioxide.
  2. Acid genesis, where occurs to consume the residual oxygen in the air, creating an anaerobic environment and formation of the higher organic acids.
  3. Acetic genesis, wherein the bacteria alter the above organic acids and alcohols into the acetic acid, hydrogen and carbon dioxide.
  4. Methanogenesis is the last stage of decomposition process, where methanogenic bacterias decompose acetic acid to methane, carbon dioxide, and hydrogen bacterias produce methane from hydrogen and carbon dioxide.

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Almost all biodegradable waste are suitable the production of substrates , but differ in their ability of fermentation decomposition and biogas generation. In the next chart you can see the biogas yield in m3 per tonne of the most frequently used materials:

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