Effect of chemical, physical, and biological pre-treatment of food wastes on bio-hydrogen production by dark anaerobic fermentation under mesophilic conditions

With an overall aim of utilizing lignocellulosic food waste as feedstock for anaerobic fermentation and optimizing the reaction for improving energy output, a two-stage anaerobic dark fermentation reactor was set up. This study discusses the evaluation of different pre-treatment methods used to pre-treat the food waste before using it as a substrate for anaerobic fermentation. Five different techniques from physical, chemical, and biological pre-treatment methods, namely, autoclaving, acid pre-treatment, alkali pre-treatment, aeration, and fungal pre-treatment were used for pre-treatment of the substrate. The analysis was also evaluated by the multilevel categoric factorial design of the experiment model. The experiment found that all five pre-treatments improved the hydrogen and methane yield from the reaction. More precisely, fungal pre-treatment shows an almost 3.8-fold improvement in hydrogen yield compared to control conditions and a 1.7-fold increase in methane yield compared to control. The statistical analysis showed that the reaction time duration (day) has a more significant impact on the results than the pre-treatment technique. The model’s F-Values of 24.14 for hydrogen yield and 44.34 for methane yield indicate substantially. However, the actual hydrogen and methane yields are in good accord with the DOE predicted results.