Effets des différentes méthodes de prétraitement sur la qualité du bio-méthane obtenu par digestion anaérobie d’un déchet organique

Abstract

This work focuses, firstly, on the study of the anaerobic digestion process of date pits (substrate) in the presence of sewage sludge (inoculum), at a mesophilic temperature (37℃). The main objective is to study the effect of pre-treatment of this substrate on the production of biogas and bio-methane, for an inoculum/substrate ratio of 1/3. Two pre-treatment methods were adopted, mechanical pre-treatment (exposure to ultrasonic waves for 15 and 30 minutes), and secondly chemical pre-treatment, using different concentrations of calcium hydroxide (1.25M, 0.625 M and 0.25M), the second method was applied at two temperatures 24 ℃ and 80℃. The results of our experiments showed that chemical pre-treatment gave better biogas and methane production. In fact, 122 ml and 33 ml of biogas and biome thane respectively were obtained with chemical pre-treatment, compared with 32 ml and 16 ml of biogas and biome thane respectively with mechanical pre-treatment. Chemical pretreatment has a positive effect on anaerobic co-digestion compared with mechanical pretreatment (ultrasonic waves) and that obtained with ordinary digestion.