Improving the Anaerobic Digestion of Garbage by Hydrothermal Treatment

概要

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In this study, an anaerobic digestion combined with hydrothermal treatment method was developed to improve the methane fermentation of garbage. Both the effects of hydrothermal conditions on garbage solubilization and that of hydrothermal treatment on anaerobic digestion were examined. (1) The results of hydrothermal treatment indicated that high temperatures may accelerate the solubilization of solids. However, a larger loss of dissolved portions was also found to be caused by the greater gasification in the solubilization treatment at high temperature and short treatment time. The maximum concentration of DOC generated under the optimum conditions (160°C and 60 min) was 50% higher than that before the treatment. (2) Methane fermentation experiments of kitchen garbage that had been crushed and hydrothermally treated separately were conducted. Results show no difference between these two pretreatment when HRT was set at 29 days. However, 10-15% increases of the degradations of SS, POC and TOC were found at HRT day 10. Furthermore, at HRT day 5, which is thought to be difficult for the degradation of garbage that has only been crushed, hydrothermal treatment caused 69%, 74% and 72% degradations of SS, POC and TOC, respectively.