Conversion Processes in Anaerobic Digestion

TLDR

The degradation of particulate organic material to methane involves six distinct conversion processes, starting with hydrolysis and followed by degradation of hydrolysis products by five independent microbial groups. The study reviews process and growth kinetic data for these six conversion processes. The kinetic data were applied to design an anaerobic digester for raw domestic sludge, and loading‑rate variations mainly affect acetate decarboxylation, potentially shifting pH and driving the digester into an acidic regime.

Abstract

Six different conversion processes are identified in the degradation of particulate organic material (biopolymers) to methane. Hydrolysis of particulate material is followed by the degradation of the hydrolysis and intermediary products by five independent groups of microorganisms. Process and growth kinetic data for the six processes are reviewed. The kinetic data are applied to the design of an anaerobic digester for raw domestic sludge. Variations in loading rates primarily affect acetate decarboxylation and, thereby, may cause shifts in pH which, in turn, cause the digester to operate in the acidic regime.