Kinetic study of the thermophilic anaerobic digestion of the fresh and precomposted, mechanically selected, organic fraction of municipal solid waste

A comparative kinetic study of thermophilic anaerobic digestion under semi-dry conditions was carried out, using the step-diffusional model and the first-order model. Data for the analysis came from the operation of a 3 m(3) digester, operated at relatively overloaded conditions, using the fresh and precomposted, mechanically selected, organic fraction of municipal solid waste as substrate. A comparison was also made with other published kinetic data using these models. The results show the coherence of the step-diffusional model, explaining some of the basic mechanisms of substrate degradation. Values of the kinetic constants involved are within the range of those previously obtained by other researchers.