Wet Digestion
The wet anaerobic digestion process is applied to liquid waste streams that are conveyable by liquid pumping. Sometimes wet systems are called Low Solids AD (LSAD). The Wet AD process can be done in reactors of two main configurations, continuously stirred tank reactors (CSTR) and plug flow reactors. The theory of the CSTR is that, through rigorous mixing, the composition of the contents of the reactor in any given spot in the tank is the same as in any other spot in the tank. The theory of plug flow, on the other hand, is that the makeup of the contents at the head of the digester is different than that of the material leaving the digester just as the material flows through the digester in the pattern like a plug through a pipe. Wet systems commonly run at total solids levels between 2 and 8 percent. Wet systems will often start with a liquid manure or waste biosolids as the backbone of their feedstock load to provide a baseload buffering affect for enhanced process stability.