Abstract:In order to solve the problem of continuous acidification of watershed in Chishui River headwater basin (Yunnan section) caused by the disorderly accumulation of historical sulfur smelting waste residue for more than 40 years, the model project of "risk management + ecological restoration" was proposed to carry out demonstration project treatment of acid waste residue and wastewater in this area through analysis of treatment approaches such as "natural attenuation", "ex-situ restoration" and "risk management and control". On the basis of identifying the pollution factors in the treatment area, the integrated risk control technology of "waste residue anti-loss, composite barrier control, suitable plant ratio, sewage collection and treatment, and operation monitoring and management" was adopted to analyze the solid waste properties before, during and after the implementation of the project, as well as the changes of pollution factors in surface water, groundwater and waste residue leachate. The results show that the property of solid waste is modified from Class Ⅱ general industrial solid waste to Class Ⅰ general industrial solid waste under the condition of adding 0.35%—0.65% lime. When the project is completed, the pH value of groundwater can meet the standard, and the times of exceeding the standard of sulfate is reduced from the maximum of 5.3 times to 1.2 times. Three months after the implementation of the project, the pH value of leachate is stable and meets the standard, and the times of exceeding the standard of sulfate is reduced from the maximum of 3.2 times to 1.7 times. 7 months after the implementation of the project, the pH value of the surface water meets the standard. The comprehensive management of historical sulfur smelting waste residue based on risk management and control can meet the management and control objectives, and the technology promotion and application have been preliminarily completed.