What is Digestate?

When an anaerobic digester processes organic material, it produces a gas (biogas) plus liquid and solid digested material.  Those liquids and solids are called digestate.

Raw or whole digestate produced by a biogas system is physically and chemically different from the organic input material used to produce it.

Key Changes To Organic Materials From Anaerobic Digestion

Undigested Inputs

  • Often heterogeneous, hard to obtain sample for accurate characterization or analysis
  • May contain bulk physical contaminants such as packaging or non-organic physical contaminants
  • Many contain and facilitate growth of pathogens, weed seeds
  • Highly unstable, putrescible (odors, VOCs, methane)
  • Nutrients predominantly in the organic form, lower plant availability
  • May be bulky, low transport efficiency


  • Homogeneous, highly representative sampling for accurate characterization
  • Physical contaminants largely removed in pretreatment
  • Substantial (>90%) reduction in pathogen levels, and kills viable weed seeds
  • Substantial stabilization and reduction in odor, VOC and methane potential
  • Nutrients predominantly shifted to inorganic form, greater plant availability PLUS additional micronutrients resulting from the die-off of the microorganisms and when used, added micronutrients.
  • Densified, higher transport efficiency

Learn more about anaerobic digestion and biogas systems