Anaerobic Digestion

Anaerobic Digestion
Anaerobic digestion involves biologically stabilizing biosolids in a closed tank to
reduce the organic content, mass, odor (and the potential to generate odor),
and pathogen content of biosolids. In this process, microorganisms consume a
part of the organic portion of the biosolids. Anaerobic bacteria that thrive in the
oxygen-free environment convert organic solids to carbon dioxide, methane
(which can be recovered and used for energy), and ammonia. Anaerobic
digestion is one of the most widely used biosolids stabilization practices,
especially in larger treatment works, partly because of its methane recovery
potential. Anaerobic digestion is typically operated at about 35o C (95o F), but
also can be operated at higher temperatures (greater than 55o C [131o F]) to
further reduce solids and pathogen content of the stabilized biosolids.

source: EPA website