Put attention on Hazardous Waste
With the development of industry, more and more hazardous wastes are discharged from industrial production process. Due to the serious pollution and potential serious impact of hazardous wastes, hazardous wastes in industrial developed countries have been called "political wastes". The public is very sensitive to the problem of hazardous wastes, coupled with the high cost of hazardous wastes disposal, some companies are trying to transfer hazardous wastes to industrial underdeveloped countries and regions. In the past, many hazardous wastes were mixed in the foreign garbage imported from China and other countries. Various hazardous chemicals were smuggled out of the country by illegal traders in waste plastics, waste paper, diapers and household garbage, and drifted across the sea to developing countries. If these articles were not handled properly, they would cause great damage to the environment.
Definition
1. Solid waste, including liquid waste.
Characteristic: One or more of corrosive, toxic, flammable, reactive and infectious, which need to be managed according to hazardous waste.
2. Medical waste belongs to hazardous waste.
3. The chemicals discarded in the Catalogue of Hazardous Chemicals belong to hazardous wastes.
4. Hazardous Wastes in the Hazardous Waste Exemption Management List
5. Solid wastes with unclear hazardous characteristics shall be identified in accordance with the standards and methods for the identification of hazardous wastes prescribed by the State.
Hazard
(1) Destroying the ecological environment. The dangerous wastes discharged randomly will pollute the water and soil under the long-term effect of groundwater, and reduce the environmental function grade of the area.
(2) Endangering human health. Hazardous wastes cause poisoning through inhalation, skin absorption, eye contact, or other dangerous incidents such as combustion and explosion; long-term hazards include long-term poisoning, carcinogenesis, mutagenicity caused by repeated exposure.
(3) Constraining sustainable development. Pollution of air, water and soil caused by non-standard disposal of hazardous wastes will restrict economic activities.
Treatment methods
1. Physical treatment: Physical treatment changes the structure of solid waste into a form that is easy to transport, store and dispose of by concentration or phase change.
2. Chemical treatment: chemical methods are used to destroy harmful components in solid waste or to transform them into forms suitable for further disposal. Its purpose is to change the chemical properties of the treated substance, thereby reducing its harmfulness. This is a common pretreatment measure before the final disposal of hazardous wastes. Its treatment equipment is conventional chemical equipment.
3. Biological treatment: Biological treatment is the use of microorganisms to decompose degradable organic matter in solid waste, so as to achieve harmless or comprehensive utilization. Biological treatment methods include aerobic treatment, anaerobic treatment and facultative anaerobic treatment. Compared with chemical treatment, biological treatment is generally cheaper and more widely used economically, but the treatment process takes longer and the treatment efficiency is not stable enough.
4. Heat treatment: Heat treatment can reduce volume, make harmless or make comprehensive use of solid waste by destroying and changing the composition and structure of solid waste at high temperature. The methods include incineration, pyrolysis, and wet oxidation, roasting and sintering. Wastes with high calorific value or high toxicity are treated by incineration process, and waste heat from incineration is recovered for comprehensive utilization, physical and chemical treatment, as well as workers ‘bathing and living, so as to reduce the cost of treatment and waste of energy.
5. Solidification treatment: Solidification treatment uses solidified substrates to fix or encapsulate wastes in order to reduce their environmental hazards. It is a relatively safe process for transportation and disposal of wastes, mainly for hazardous wastes and radioactive wastes. The volume of solidified body is much larger than that of original wastes.
6. All kinds of treatment methods have their advantages and disadvantages and applicability to different wastes. It is difficult to have a unified model because of the different components and properties of hazardous wastes. For the characteristics of various wastes, the treatment method with strong applicability can be chosen.
