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Food waste treatment with a leachate bed reactor: Effects of inoculum to substrate ratio and reactor design

Xiong, Ziyi, Hussain, Abid, Lee, Hyung-Sool
Bioresource technology 2019 v.285 pp. 121350
biorefining, chemical oxygen demand, energy balance, food waste, hydrogen production, hydrolysis, inoculum, leachates, waste treatment
This study evaluated the effects of different inoculum to substrate ratios (ISRs) (5, 10, 15%) on hydrolysis and acidogenesis of food waste in a conventional leachate bed reactor (LBR-C) and a novel fractionalized LBR (LBR-F). At ISR of 10%, LBR-C experienced clogging and thus the solid removal and VFA production reduced significantly. Without any clogging events at high ISR of 10%, LBR-F achieved significantly higher (p < 0.05) VS removal of 91%, hydrolysis yield of 837 g cumulative sCOD/kg volatile solids (VS), and VFA yield of 669 g COD/kg VS. Hydrogen yield was as high as 20 m3/ton food waste in LBR-F. Energy balance indicated that the LBR-F can be energy-positive for food waste treatment with net energy benefit of ∼8 kWh/ton food waste treated. Considering the high VFA yield, the LBR-F can also be a promising food waste fermentation system for the biorefinery platform.