Analysis of micro-particle effect and methanogenic potential of food waste model compounds by hydrothermal pretreatment.

• The micro-particle effect of hydrothermal pretreatment on matrix was verified. • Low temperature hydrothermal pretreatment was more conducive to methane generation. • Hydrothermal pretreatment coupled anaerobic fermentation could achieve zero waste discharge. Anaerobic fermentation is one of the ways to realize the recycling, harmlessness and reduction of food waste. The potential of methane production via anaerobic fermentation was analyzed by the model compounds of food waste after hydrothermal pretreatment, and the micro-particle effect of hydrothermal pretreatment on matrix was verified by the change of physicochemical properties and morphology characteristics of model compounds of food waste in hydrothermal group, and the influence of hydrothermal pretreatment on anaerobic fermentation methane production was explored. From the perspective of particle size, the hydrothermal groups had good decomposition characteristics. With the increase of hydrothermal temperature, the surface morphology changed from smooth to rough, and the specific surface area increased from 0.29 m2·g−1 in the control group to 2.82 m2·g−1 in the hydrothermal group at 200 °C. In addition, the model compounds of food waste were anaerobic fermented under the condition of constant temperature water bath (55 °C). The results showed that the methane yield of 140 °C hydrothermal group was the highest (0.368 NL·g−1 VS), which increased by 27.78% compared with the control group, and the methane generation performance of the fermentation process was improved. Through material balance and energy analysis, it is revealed that hydrothermal pretreatment coupled anaerobic fermentation could achieve zero waste discharge and partial energy recovery. [ABSTRACT FROM AUTHOR]