Enhancing Hydrogen and Resource Recovery from Food Waste: A Cascading Approach from Concept to Process

Effective management of food waste (FW) is essential for achieving energy self-sufficiency and carbon neutrality in food waste treatment plants (FWTPs). Developing a multitandem and efficient FW treatment process is crucial for performing more energy recovery at on-site plants. In this study, a cascading process was developed to treat FW from generation to complete disposal. Compared with the unpretreated FW (UP-FW), enzymolysis exhibited higher hydrolysis efficiencies for FW. Specifically, the concentrations of glucose, chemical oxygen demand, and total organic carbon increased by 259.42%, 49.31%, and 33.08%, respectively. The pretreated FW exhibited a considerable hydrogen yield of 35.81 ± 1.47 mL/g-VS, roughly double that of raw FW used as the substrate, which was also accompanied by 26.52% and 19.10% increases in ethanol and acetate production, respectively. The recyclable catalyst (FRB800) pyrolyzed from the fermentation residue showed superior Orange G (OG) removal efficiency and better anti-interference ability in the actual water body. OG could be completely removed within 30 min, dominated by singlet oxygen, nonradical pathways, and diverse active sites on FRB800. This process synchronizes the recovery of hydrogen and resources with the degradation of pollutants. Overall, these findings indicate that the cascading process is an alternative approach to the complete disposal of food waste and possesses significant engineering value and broad application prospects for FWTPs.