Assessment and projection of environmental impacts of food waste treatment in China from life cycle perspectives

China produces vast amounts of food waste every year. However, the environmental impact of the current treatment of food waste and its potential for improvement are not very clear. Therefore, this study applied life cycle assessment to compare the current major treatment options for food waste and to systematically quantify the environmental impact of current and future food waste treatment in China based on the amount and treatment mode of food waste. In 2020, 125 million tons (Mt) of food waste was generated in China. Its treatment consumed 30.1 Mt oil-Eq of fossil fuels and 16.7 Mt of freshwater, and released 37.5 Mt of CO2-Eq. A promising finding was that if the proportion of food waste treated by anaerobic digestion exceeded 40% and landfilling was terminated by 2050, most impact categories would be reduced by more than 50%. Although anaerobic digestion is a potentially more environmentally friendly treatment option due to more output of energy and resources, it is worth noting that it consumed more freshwater than incineration and landfilling. Electricity consumption contributed more than 50% of the environmental burden of anaerobic digestion. Therefore, for the upstream of anaerobic digestion, China should further implement policies of waste classification and promote zero-waste cities, so that less impurities and more food waste would enter anaerobic digestion instead of landfills. Whereas downstream, the resource utilization of biogas and digestate enhance should be enhanced so as to strengthen the environmental sustainability of anaerobic digestion.