The Impact of Alkali Pretreatment and Organic Solvent Pretreatment on Biogas Production from Anaerobic Digestion of Food Waste

Anaerobic digestion of food waste is an encouraging technology for biogas production. Pretreatment of the sub-strate is needed to increase biodegradation. This study aimed to investigate the effect of alkali pretreatment and organic solvent pretreatment on biogas production. Physical pretreatment was also applied in this study. NaOH (0%, 2%, 4% and 6%) was used as alkali pretreatment. Ethanol (0, 2, 4 and 6%) was used as organic solvent pre-treatment. The experiment was conducted in a 1 L batch digester under room temperature. Results showed that 0% NaOH generated the highest cumulative biogas yield of 46.1 mL/gVS. The best biodegradability of 37.5% was achieved in NaOH of 0%. The lower concentration of ethanol generated a higher biogas yield. The greatest cumu-lative yield of 41.5 mL/gVS was obtained at an ethanol concentration of 0% with a biodegradability of 33.84%. Statistical analysis proved that alkali pretreatment and organic solvent pretreatment had no significant effect on biogas production (p>0.05). Physical pretreatment had a significant effect (p<0.05) with the highest cumulative yield of 58.2 mL/gVS. The kinetic model proved that the modified Gompertz was a suitable model for predicting and simulating the kinetics of anaerobic digestion from food waste (R2 > 0.9).