Life cycle assessment of food waste energy and resource conversion scheme via the integrated process of anaerobic digestion and hydrothermal carbonization

Anaerobic digestion is the mainstream method for energy conversion of food waste, but dewatering and resource utilization of its digestate is the downstream technical obstacle. In this study, an energy and resource utilization scheme via the integrated process of anaerobic digestion and hydrothermal carbonization of food waste is proposed, among which the hydrothermal carbonization not only is used to remove water from digestate in a non-phase change manner with low energy consumption but also convert digestate into hydrochar. Moreover, the scheme has the least environmental impact compared to the anaerobic digestion and composting treatment by life cycle assessment. In particular, it has a lower impact potential (-141.46 kg CO2 eq) than anaerobic digestion (-38.87 kg CO2 eq) for the global warming category, indicating that the addition of hydrothermal carbonization can bring better environmental benefits. This study provides a reference for the development of disposal technology for food waste. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.