Review of Opportunities and Challenges for Food Waste Circular Economy Advancement via Hydrothermal Carbonization

The availability and accessibility of natural resources are essential for both the preservation of quality of life and the advancement of economic progress. Therefore, it is imperative to prioritize the sustainable utilization of existing natural resources to guarantee the achievement of long-term resource security. Circular economy (CE) is an economic framework that seeks to advance sustainable development by optimizing the utilization of natural resources. The basic objective of the CE is to mitigate the consumption of primary raw materials and energy resources. One viable strategy for attaining this objective involves the extraction of valuable resources from waste sources, followed by their reintegration into the production process/supply chain as secondary raw materials and in this regard, the inherent nature and broad accessibility of food waste make it a promising and practical raw material for resource recovery. Hydrothermal carbonization (HTC) has emerged as a promising technique for the efficient utilization of food waste, enabling the extraction of energy, platform chemicals, and a wide range of bio-based products. It is envisaged that the implementation of hydrothermal carbonization technology for the extraction of resources from food waste can serve as a facilitator in the building of a CE platform. This review provides a comprehensive analysis of the diverse valorisation outcomes attainable through the application of HTC of food waste. It draws upon recent studies to evaluate the emerging pathways through which food waste has the potential to contribute to the core principles of a CE using hydrothermal carbonisation.