Current Status of Food Waste Anaerobic Digestion and Challenges in Carbon Source Production in China

• • Anaerobic digestion of each ton of food waste yields 70–80 Nm³ biogas, but simultaneously produces 69–80% liquid digestate and 2.7–3.6% solid digestate, creating a seasonal mismatch with land application that restricts resource utilization. • • Oil recovery from leachate via three-phase separation exceeds 98%, yet the remaining digestate streams still pose a management challenge due to high NH4+-N and continuous generation. • • Converting food waste to carbon source increases economic benefits by >203% compared to biogas route, but requires controlling SS and organic nitrogen to avoid adverse effects on activated sludge systems. • • Carbon source production via hydrolysis-acidification suffers from long fermentation periods and poor shock resistance, while pretreatment+membrane filtration retains SCOD but loses biodegradable particulate COD and retains some soluble organic nitrogen.