Biogas production by an anaerobic co-digestion process from olive mill waste: effect of ultrasonic pre-treatment

In the current study, the biochemical methane potential test was carried out to estimate the biogas production from Olive mill waste by using an anaerobic digestion process in the mesophilic phase (T = 37 degrees C). The goal of this study is to promote the hydrolysis step so that a maximum volume of biogas and methane are obtained through performing an ultrasonic treatment of olive mill waste which is rich in organic matter (99.95%). The ultrasonic pretreatment was carried out along the following exposure times: 2, 7, 12 and 17 min which were investigated for the optimization. An increase in kinetic of biodegradability of the substrate and an improvement in methane yield were observed. The obtained results showed that the ultrasound pretreatment has a positive effect on the hydrolysis phase and the volume of produced methane, which results in an increase in soluble chemical oxygen demand levels from 73% to 78%, and a significant increase in methane production from 42 to 88.49 mL/g TVS.