In recent years, with the continuous improvement of wastewater treatment requirements, "zero discharge" technology has been increasingly applied to the treatment of industrial wastewater. During the process of "zero discharge" of wastewater, a large amount of industrial waste salt will be generated. At the same time, some by-products of salt will also be produced in the chemical industry reaction process. Are these industrial waste salts hazardous waste?
Industrial waste salt refers to solid or solution waste containing salt compounds generated in industrial production processes, mainly from high salt wastewater crystallization products or intermediate by-products of chemical synthesis in industries such as chemical, petroleum, textile, printing and dyeing, pharmaceuticals, pesticides, etc.
The "Technical Specification for Pollution Control of Waste Salt Utilization and Disposal (Pesticide Industry)" (draft for comments) proposes that the storage of waste salt should comply with the requirements of GB 18597, and transportation should comply with the relevant national regulations on the transportation of dangerous goods.
In the management process, to determine whether industrial waste salt belongs to hazardous waste, first determine its composition, compare it with relevant product quality standards, and confirm whether it can meet the requirements of relevant product standards. If it can meet the product standards, it should be managed according to the requirements of GB34330 and not according to hazardous waste.
Analyze whether there may be hazardous substances entering the waste salt, determine the pollution characteristics of the waste salt, and then identify it according to the GB5085.7 series standards and HJ298 to determine its solid waste properties.
Based on the National Hazardous Waste List and hazardous waste identification technical specifications, some substances in industries such as C26 (chemical raw materials and chemical manufacturing), C27 (pharmaceutical manufacturing), and C28 (chemical fiber manufacturing) may be directly identified through standards.
Because in the 2021 National Hazardous Waste List, various waste materials such as distillation and reaction residues, waste mother liquor, reaction tank and container cleaning waste from production processes are included in the hazardous waste list.
For example, the Hazardous Waste List (2021 edition) stipulates that waste mother liquor (271-002-02) generated during the production of chemical synthetic raw materials, waste mother liquor (263-009-04) generated during the production of pesticides, waste mother liquor (265-102-13) generated during the synthesis, esterification, condensation and other processes in the production of resins, synthetic latex, plasticizers, adhesives/binders, as well as residues or waste liquids at the bottom of distillation towers in chemical reactions listed in the list (there are many such substances, and specific information can be found in the Hazardous Waste List, which is only listed above).
If the source of waste salt in chemical enterprises is from the treatment of mother liquor or waste liquid listed in the hazardous waste list, according to the "General Rules for Identification Standards of Hazardous Waste" (GB 5085.7-2019), then this type of waste salt belongs to hazardous waste.
In the General Principles for Identification Standards of Hazardous Waste (GB 5085.7-2019), Part 6 of the rules for determining the utilization and disposal of hazardous waste clearly stipulates that, except as otherwise provided by relevant national regulations and standards, solid waste generated after the disposal of hazardous waste with toxic hazardous characteristics still belongs to hazardous waste.
Most of the waste mother liquor and distillation residue listed in the directory belong to hazardous waste with toxic and hazardous characteristics. According to GB5085.7, solid waste generated after the treatment of such waste mother liquor and distillation residue, namely waste salt, still belongs to hazardous waste.
Therefore, according to the "National Hazardous Waste List" (2021 edition) and the principles of determining the properties of solid waste after hazardous waste disposal in GB5085.7, if the waste salt generated by the enterprise comes from various waste mother liquors and distillation residues listed in the list, and the salt does not meet the product quality standards, it belongs to hazardous waste.
