Types of Anaerobic Digesters
Complete mixed digester vessels are insulated and maintained at a constant elevated temperature, in the mesophilic or thermophilic range.
A covered lagoon digester is a large anaerobic lagoon (not a manure storage pond or basin) with a long retention time and a high dilution factor.
A fixed film digester vessel is filled with an inert medium or packing that provides a very large surface area for microbial growth.
A plug flow digester vessel is a long narrow (typically a 5:1 ratio; 5 times as long as the width) insulated and heated tank made of reinforced concrete, steel or fiberglass with a gas tight cover to capture the biogas.