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Vivi has shared a great deal of knowledge regarding the transportation and storage of hazardous materials, as well as many educational pieces on hazardous chemicals. Today, Vivi would like to talk with everyone about hazardous waste. I. Overview of Hazardous Waste Hazardous waste refers to dangerous waste generated during industrial production processes, mainly including waste acids, waste alkalis, asbestos waste, smelting waste, waste mineral oils, etc., produced in industries such as chemicals and metallurgy. In accordance with the Law of the People’s Republic of China on the Prevention and Control of Environmental Pollution by Solid Wastes, hazardous waste refers to solid wastes that are included in the **List of Hazardous Wastes**, or those that are identified as having hazardous characteristics in accordance with the **established criteria and methods for identifying hazardous wastes**. II. Hazards of hazardous waste (1) Damage to the ecological environment. Hazardous waste that is discharged or stored carelessly can contaminate water bodies and soil due to the long-term seepage and spread of rainwater and groundwater, thereby reducing the environmental quality of the area. (2) Affect human health. Hazardous waste can cause poisoning through ingestion, inhalation, skin absorption, or eye contact, or it can lead to dangerous incidents such as fires; long-term hazards include chronic poisoning resulting from repeated exposure. (3) Restricting sustainable development. The pollution of the atmosphere, water sources, soil, etc., caused by the improper or unsanitized disposal of hazardous waste will also become a bottleneck restricting economic activities. III. Methods of treating hazardous waste 1. Physical treatment: Physical treatment involves altering the structure of solid waste through concentration or phase changes, so that it can be transported, stored, utilized, or disposed of more easily. This includes methods such as compaction, crushing, sorting, thickening, adsorption, and extraction. 2. Chemical treatment: Chemical treatment involves using chemical methods to destroy the harmful components in solid waste, thereby rendering it harmless or transforming it into a form suitable for further treatment or disposal. Its purpose is to change the chemical properties of the substance being treated, thereby reducing its harmfulness. This is a common pretreatment method used before the final disposal of hazardous waste, and its treatment equipment consists of standard chemical engineering equipment. 3. Biological treatment: Biological treatment involves using microorganisms to break down the biodegradable organic substances in solid waste, thereby rendering it harmless or enabling its comprehensive utilization. Biological treatment methods include aerobic treatment, anaerobic treatment, and facultative anaerobic treatment. Compared to chemical treatment methods, biological treatment is generally cheaper and more widely used economically, but it requires a longer processing time and its efficiency is not very stable. 4. Heat treatment: Heat treatment involves using high temperatures to destroy and alter the composition and structure of solid waste, thereby achieving the goals of reducing its volume, rendering it harmless, or enabling its comprehensive utilization. Its methods include incineration, pyrolysis, wet oxidation, as well as roasting and sintering. Waste with a high calorific value or high toxicity is treated in an incineration process to render it harmless, and the waste heat generated from incineration is recovered for various uses such as comprehensive utilization, physical and chemical treatment, as well as for staff bathing and daily living, thereby reducing treatment costs and energy waste. 5. Solidification treatment: This process involves using a solidifying substrate to fix or enclose waste, thereby reducing its impact on the environment. It is a method that enables safer transportation and disposal of waste, and it is primarily used for hazardous and radioactive waste. The volume of the solidified material is much larger than that of the original waste. 6. Various treatment methods have their own advantages and disadvantages as well as suitability for different types of waste; it is difficult to establish a uniform approach due to the differences in components and properties of various hazardous wastes. Appropriate treatment methods can be selected based on the characteristics of each type of waste. IV. Project approval process: Hazardous waste projects generally need to go through the following stages: signing of the investment agreement → preparation and submission of the project application report → environmental impact assessment (including five phases: first public announcement, second public announcement, acceptance, pre-approval public announcement, and approval) → preliminary work → commencement of construction → trial operation → completion inspection → issuance of a temporary operating license → issuance of a formal operating license. Among these, the issuance of environmental impact assessment and operation permits is a crucial step. Currently, the operation permits are approved and issued by the environmental protection authorities at the county level, while the permits related to collection, storage, and disposal are approved and issued by the environmental protection authorities at the provincial level. Hazardous chemicals are dangerous, and so are hazardous waste; improper handling of them can cause severe environmental pollution. Chemical companies should pay attention to the proper disposal of hazardous waste, comply with the relevant policies in various provinces, and reduce harm to the environment.