Anaerobic Digestion of Yard Waste with Hydrothermal Pretreatment
The digestibility of lignocellulosic biomass is limited by its high content of refractory components. The objective of this study is to investigate hydrothermal pretreatment and its effects on anaerobic digestion of sorted organic waste with submerged fermentation. Hydrothermal pretreatment (HT) was performed prior to anaerobic digestion, and three agents were examined for the HT: hot compressed water, alkaline solution, and acidic solution. The concentrations of glucose and xylose were the highest in the sample pretreated in acidic solution. Compared with that of the untreated sample, the biogas yields from digesting the samples pretreated in alkaline solution, acidic solution, and hot water increased by 364, 107, and 79 %, respectively. The decrease of chemical oxygen demand (COD) in liquid phase followed the same order as for the biogas yield. The initial ammonia content of the treated samples followed the order sample treated in acidic solution > sample treated in alkaline solution > sample treated in hot water. The concentrations of volatile fatty acids (VFAs) were low, indicating that the anaerobic digestion process was running at continuously stable conditions.
KeywordsAnaerobic digestion Hydrolysis Hydrothermal Biogas Municipal solid wastes
The authors acknowledge the financial support from Hi-Tech Research and Development Program of China (863 Program, 2012AA021401), National Natural Science Foundation of China (21161140329), and National Key Technology R&D Program National Key Technology Support Program (2012BAC03B05).
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