Process enhancement for maximization of methane production in codigestion biogas plants

Purpose – The purpose of this paper is to develop improvements in the efficiency of the codigestion process. Design/methodology/approach – Two pilot plants, fed by different compositions of manure and industrial organic waste, generating biogas by mesophilic and thermophilic anaerobic fermentation, respectively, were analysed. Findings – It was observed that these processes do not commonly operate at maximum theoretical efficiency. Research limitations/implications – The limiting factor in the process was found to be the hydrolysis of the digested material. Practical implications – A technical solution had been suggested: implementing a secondary (after) storage phase which has the purpose of exploiting, by promoting enhanced hydrolysis, the substrate potential that remains undigested after the traditional process. Originality/value – The proposed configuration opens to original variations in the anaerobic digestion schemes.