The original site of Chongqing Hua'nan Industrial Salt Chemical Co., Ltd. is located in Zhongyao Village, Jiguanshi Town, Nan'an District, Chongqing, covering an area of 7778.3 m2, including 5825.3 m2 of land ownership red line area and 1953m2 of leased land production and use area. The restored land was farmland before 1983; Chongqing South China Chemical Plant, the production enterprise in the plot, built workshops and production lines from 1983 to 1987; 1987~1997 engaged in the production of barium chromate, lead nitrate and aluminum nitrate; In 1997, Chongqing South China Chemical Plant was restructured into Chongqing South China Inorganic Salt Industry Co., Ltd; From 1997 to April 2019, he was engaged in the production of aluminum nitrate, strontium chloride, potassium chlorate, strontium nitrate, strontium carbonate, iron phosphate and copper pyrophosphate; In April 2019, the enterprise completely stopped production.

In October 2021, Chongqing Hua'nan Industrial Salt Chemical Co., Ltd. entrusted Chongqing Aoyue Environmental Protection Technology Research Institute Co., Ltd. to complete the soil pollution survey and risk assessment of the plot. According to the Investigation Report on Soil Pollution at the Original Site of Chongqing South China Inorganic Salt Industry Co., Ltd. (submitted for approval) and the Assessment Report on Soil Pollution Risk at the Original Site of Chongqing South China Inorganic Salt Industry Co., Ltd. (submitted for approval), the health risk of hexavalent chromium in the soil of the wastewater treatment area and barium chromate production workshop in the plot exceeds the maximum acceptable level of human risk, and the risk comes from hexavalent chromium, The total area of contaminated soil is 265.7m2 by interpolation calculation, and the total area of contaminated soil (including large size stones) is 380.2m3; There are about 6m3 of contaminated building slag and sludge left in the wastewater treatment tank in the repaired plot. In the same month, Chongqing South China Inorganic Salt Industry Co., Ltd. entrusted Chongqing Aoyue Environmental Protection Technology Research Institute Co., Ltd. to prepare the technical plan for soil pollution treatment and remediation of the plot, and entrusted Chongqing Zhanpeng Construction Services Co., Ltd. to be responsible for the construction of the project.

According to the site conditions, soil physical and chemical properties, types and characteristics of pollutants, and characteristics of pollution media, this remediation plan analyzes and compares the existing remediation technologies from the aspects of technical maturity, remediation effect, remediation duration and cost, and determines that the collaborative disposal technology of clay rotary kiln is adopted for contaminated soil; After the collection and packaging of hazardous waste, it shall be disposed by Chongqing Zhongming Gangqiao Environmental Protection Co., Ltd. with a hazardous waste business license; The construction wastewater in the site is transported to Chongqing Zhilun Electroplating Co., Ltd. for treatment after treatment.