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Anaerobic Digestion
Anaerobic Digesters harness naturally occurring bacteria to break down organic compounds or biomass in municipal and industrial waste streams. Methane based Biogas is generated as a by-product of the digestion process and can be captured for use in fuel generators. Residual solids can be separated from liquids to provide a nutrient rich organic soil fertiliser.

As the name suggests, anaerobic bacteria live in an environment that is free of oxygen, compared to aerobic composting that requires oxygen to work. Anaerobic digesters have a very high rate of pathogen destruction and the resulting effluent has little detectable odour.

Anaerobic Digestion Process
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stages of anaerobic digestion
Anaerobic digestion of organic solids involves a range of different species of naturally occuring bacteria, each perfoming a specific function at the appropriate step in the digestion process. Maintaining consistent conditions and temperatures in the Digester is essential in keeping a healthy bacterial population.
  1. HYDROLYSIS: Complex organic molecules are broken down into simple sugars, amino acids and fatty acids with the addition of hydroxyl groups.

  2. ACIDOGENESIS: A further breakdown into simpler molecules such as volatile fatty acids (acetic, propionic, butyric, valeric) occurs, prodcuing ammonia, carbon dioxide and hydrogen sulphide as by-products.

  3. ACETOGENESIS: The simple molecules from acidogenesis are further digested to produce carbon dioxide, hydrogen and mainly acetic acid.

  4. METHANOGENESIS: Methane, carbon dioxide and water are produced.
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