The management of the wastewater originating from olive oil producing industries poses a serious environmental problem. Recently, two-phase production of olive oil has been developed, leading to almost complete elimination of the bulk of the generated wastewater and, is thus regarded as an environmentally friendly technology. However, the main waste stream (olive pulp) is a slurry material characterized by high solids concentration (approximately 30%), requiring stabilisation before its final disposal. The anaerobic digestion of olive pulp is studied in this work under mesophilic and thermophilic conditions in CSTR-type digesters. The digesters were fed with water-diluted (1:4) olive pulp at an HRT of 20 days and an OLR of 3.94 kg COD m(-3) d(-1). In order to study the process kinetics, the digesters were subjected to impulse disturbances of different substrates. The IWA anaerobic digestion model was used to simulate the reactors' response. Some key process parameters, such as the specific maximum uptake rate constants and the saturation constants for the volatile fatty acids degradation were estimated and compared with the standard values suggested by the ADM1.