
214 Principles of Sustainable Energy Systems
© 2008 Taylor & Francis Group, LLC
Anaerobic digester designs include batch, plug-ow, and continuously stirred tank, upow,
and two-tank reactors. The batch reactor is a single vessel design in which all steps of the
digestion process take place. Advanced reactors aim to improve waste contact with active bac-
teria and/or to separate and control the environments for acid-forming and methane-forming
bacteria. Modifying multiple variables can optimize anaerobic digestion: waste pretreatment,
heating, mixing, nutrient addition, specialized bacteria addition, and pH among others.
4.2.2.2 Biomass to Synt ...