The processing of biosolids can yield energy products with low carbon intensity.  Traditionally, this has included the use of biogas generated in anaerobic digestion to produce electricity with engines or heat with boilers, but recent innovations have included a broader range of uses for biogas and biosolids.

  • Aerobic digestion — Aerobic digestion is the breakdown of organic material in the presence of oxygen. Essentially, oxygen-loving microorganisms will degrade organic material, reducing the volume of sludge solids. This is usually done as part of wastewater treatment.
  • Anaerobic digestion — Anaerobic digestion is the breakdown of organic material without oxygen. Different microorganisms break down fats, carbohydrates, and proteins just like what happens in a cow’s gut. Like in a cow, the food is masticated (chewed) then enters the stomach and guts and is broken down, until only nutrient-rich semisolids and biogas (methane and carbon dioxide) remain.


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