How to classify hazardous waste in sludge storage facilities?


Is Sludge a Hazardous Waste?

Several relevant mandatory national standards and industry standards have been implemented to regulate the development of hazardous waste management in enterprises and industrial parks, and promote the reduction of hazardous waste production in China.

Standards have been implemented to regulate the development of hazardous waste management in China.


The sludge produced by public sewage treatment plants, which are purely used to treat urban domestic sewage, usually doesn’t have hazardous properties and can be managed as general solid waste.​​


However, the sludge produced by the treatment facilities that specially treat industrial wastewater (or treat a small amount of domestic sewage at the same time) may have hazardous characteristics, and should be classified as hazardous waste by the "National List of Hazardous Wastes" and the national environmental protection standard "Technical Specifications for Hazardous Waste Identification."


The third category is a public sewage treatment plant with the main function of treating domestic sewage. Occasionally this kind of plant receives and treats industrial wastewater that needs to meet the national or local pollutant discharge standards before being discharged into the public sewage treatment system.


The fourth category is the industrial wastewater discharged by enterprises directly or indirectly outside its legal boundaries. For the classification of hazardous characteristics, sampling complies with the "Technical Specifications for Identification of Hazardous Wastes", and the sampling minimum is determined according to the amount of sludge produced.


Several types of sludge:


Electroplating wastewater and electroplating sludge with excessive heavy metals:


 Electroplating sludge belongs to hazardous waste if heavy metals exceed the standard of wastewater pollution prevention and control - if the first-class heavy metals (such as lead, mercury, chromium, cadmium, arsenic) in the wastewater exceed the standard by 3 times, or the second-class heavy metals (such as nickel, copper, zinc, manganese, vanadium) exceed the standard by more than 10 times.


Sludge from domestic sewage treatment plants:


It is classified as solid waste, not hazardous waste. According to the document [2010] No. 157 of the Environmental Protection Office, to manage this type of sludge, it is necessary to “refer to the management of hazardous wastes”, meaning that although this type of sludge does not belong to hazardous waste, it is still necessary to improve the management to prevent dripping and illegal dumping during transportation. However, most of the sludge produced in the process of sewage treatment in industrial enterprises should belong to the category of hazardous waste because its leaching toxicity exceeds the standard, or it contains other toxic and harmful substances and other dangerous characteristics (the determination method is mainly based on the environmental impact assessment of enterprises, industry rules, materials, etc.).


Fly ash from domestic waste incineration:


Classified as hazardous waste. However, if it meets the requirements of Article 6.3 in the "Standards for Pollution Control of Domestic Waste Landfills" (GB16889-2008) for domestic waste landfills, it will not be exempt from the hazardous waste management.


Sludge produced in the process of sewage treatment in medical institutions:


Most of it is hazardous waste. "Medical Waste Management Regulations" (Order No. 380 of the State Council) stipulates, "medical waste refers to the direct or indirect infectious, toxic and other harmful substances produced by medical and health institutions in medical treatment, prevention, health care, and other related activities."


According to the Ministry of Emergency Management, the Safety Committee of the State Council recently issued the "Three-Year Action Plan for National Work Safety Remediation" (referred to as the "Three-Year Action Plan"). The annual operation started in April 2020 and ended in December 2022. This included organizing a comprehensive inspection of hazardous wastes such as discarded hazardous chemicals. Chemical parks and chemical enterprises are the key targets for remediation. It is required that the entire process of hazardous waste storage, transportation, and disposal be supervised and implemented to ensure the safe disposal of hazardous wastes.


The special treatment of hazardous waste is one of the key points of the "Three-Year Action Plan".


In terms of the safety remediation of hazardous wastes, the "Three-Year Action Plan" indicates that it will be carried out from several aspects such as implementing hazardous waste investigations, improving the hazardous waste management mechanism, and accelerating the construction of hazardous waste disposal capacity.


Hazardous waste disposal capacity is the final link in the disposal of hazardous waste that cannot be ignored either. In this regard, the "Three-Year Action Plan" proposes that various storage facilities should reasonably plan and arrange disposal according to the type and quantity of hazardous wastes generated in the region to maximize the regional hazardous waste disposal capacity. Attention should be paid to the level of hazardous waste, and special emphasis should be given to the development of disposal technology and equipment.


The businesses that generate hazardous waste should also formulate a hazardous waste management plan, and report to the local environmental protection authority at or above the county level on production volume, flow direction, hazard level, storage facilities, and disposal facilities, as well as on entrusted external organizations and businesses. The hazardous waste storage time should not exceed one year, and it is strictly forbidden to mix hazardous waste with non-hazardous waste.


This means that in the field of hazardous waste treatment, several relevant mandatory national standards and industry standards have been implemented to regulate the development of hazardous waste management in enterprises and industrial parks, and promote the reduction of hazardous waste production in China.