Evaluation of biogasification and energy consumption from food waste using short-term hydrothermal pretreatment coupled with different anaerobic digestion processes

The effect of short-term hydrothermal pretreatment (SHP) before conducting two different anaerobic digestion (AD) processes on the enhancement of biogasification from food waste (FW) was evaluated. Results suggested that the highest biohydrogen and methane production rates were 13.33 mL/h and 15.81 mL/h, respectively, in the two-stage AD process with SHP (SHP-T). The regularity of ethanol and volatile fatty acid yields indicated that the fermentation type changed from a butyric acid-type to an ethanol-type during the SHP-T. Moreover, a combination of fluorescence excitation-emission matrix spectra and parallel factor analysis was used to isolate three fluorescent components. Among which, the major component was protein-like substances. According to energy flow analyses, SHP-T obtained the highest net energy gains among the different AD processes. This phenomenon showed that the new SHP-T technology had remarkable application potential for FW biogasification and complied with criteria relating to green energy concepts and sustainable development.