The Zhenjiang City Food Waste and Domestic Sludge Co-treatment Project is located in Zhenjiang, Jiangsu Province. The project adopts the process of “food waste source separation pre-treatment + sludge hydrothermal hydrolysis + anaerobic co-digestion of sludge and food waste + solar energy drying and dehydration of digestate + biogas purification and refining for natural gas production”. This approach enables the co-processing of food waste and domestic sludge to fully realize resource utilization and achieve near-zero emissions. The digestate, digestate liquid, and biogas produced by hydrothermal hydrolysis and anaerobic digestion can be effectively utilized. The recovered grease after treatment is refined into biofuels by qualified operators, establishing complete carbon, energy, and water cycles to attain urban organic waste’s green, circular, and low-carbon goals.