Anaerobic Digestion of Molasses for Methane Production

Bio-refineries produce large volumes of waste streams with high organic content, such as molasses, which have potential for further processing. Anaerobic digestion can be a key technology for treatment of these sidestreams. However, the high concentration of salts in molasses can cause inhibition of methanogenesis.

In this published  research conducted by the team of Jo De Vrieze from Ghent University, Belgium, concentrated and diluted molasses were subjected to biomethanation in two types of submerged anaerobic bioreactors, one with biogas recirculation and one with a vibrating membrane. Both reactors were compared in terms of methane production and membrane fouling.

Analysis revealed that, using the bioreactor with biogas recirculation can avoid membrane fouling. The use of diluted molasses as raw material led to a more stable methane production while concentrated molasses caused a decrease in methane production. Results also revealed the clear advantage of using Methanosaetaceae over Methanosarcinaceae in methane production.