The medical waste disposal has become a major concern for countries worldwide. Medical waste carries a large number of infectious pathogens. Improper handling of medical waste poses a significant threat to the environment.
Currently, common methods for disposing of medical waste mainly include high-temperature incineration, sanitary landfill, and pyrolysis technology. Each method has its unique technical principles, applicable scope, and advantages and disadvantages.
High-temperature Incineration
High-temperature incineration is currently a widely used medical waste disposal method. Medical waste is mainly composed of organic hydrocarbons, contains a large amount of combustible components, and has a high calorific value. In this deep oxidation chemical process, infectious agents and harmful substances in medical waste are effectively destroyed, thus achieving harmless treatment. Incineration technology is suitable for various infectious medical wastes, with advantages such as significant reduction in volume and weight and obvious waste destruction.
However, its disadvantages cannot be ignored. High cost is a major problem. Moreover, air pollution is severe during incineration, easily producing harmful gases such as dioxins. Therefore, a complete exhaust gas purification system is required. In addition, bottom ash and fly ash are also hazardous and require further treatment.
Sanitary Landfill
Sanitary landfill is one of the final medical waste disposal methods. Its principle is to bury the waste underground, where microorganisms decompose it into harmless substances over a long period of time. This method is relatively simple in process, requires less investment, and can handle large quantities of medical waste. However, landfill disposal must be approached with extreme caution, and thorough anti-seepage measures must be implemented to protect human health.
Sanitary landfilling offers less waste volume reduction, requires significant investment in landfill construction, and occupies large amounts of land. It also generates large quantities of harmful gases and volatile organic compounds, necessitating long-term monitoring of the soil and groundwater.
Pyrolysis Method for Medical Waste Disposal
Compared to incineration, the advantages of medical waste pyrolysis are comprehensive, primarily reflected in environmental friendliness, safety, and resource recovery.
Environmental Protection
Pyrolysis is performed in a strictly anaerobic or oxygen-free environment. Organic components undergo chemical bond breakage, generating small-molecule fuel gases, fuel oil, and solid charcoal residue. This fundamentally eliminates the conditions for dioxin formation.
The pyrolysis process stabilizes most heavy metals in the resulting charcoal residue. This significantly reduces the risk of their volatilization into the atmosphere and their migration capacity within the environment.
The medical waste pyrolysis process does not produce large amounts of combustion flue gas. The main gases to be treated are the exhaust gases from the external fuel used to heat the system and a small amount of non-condensable gases. This makes subsequent waste gas purification systems simpler, more efficient, and less costly.
Process Safety
The pyrolysis reactor typically maintains a high temperature above 450°C, with a long material residence time. This high-temperature, oxygen-deficient environment thoroughly and efficiently inactivates all bacteria, viruses, and other pathogenic microorganisms. Its treatment effect fully meets the sanitary standards for medical waste treatment.
Pyrolysis plant is typically fully enclosed and operate under negative pressure. The entire process, from feeding and pyrolysis to slag discharge, is conducted within a closed system. This effectively prevents the escape of harmful gases and dust, avoiding secondary pollution during the treatment process.
Resource Recovery
Through pyrolysis, medical waste typically achieves a volume reduction rate of over 90%. This significantly reduces the amount of residue required for final landfill. The pyrolysis process converts the organic components of medical waste into pyrolysis oil, syngas, and carbon black.
Pyrolysis oil is a fuel oil with a considerable calorific value, suitable for use in industrial boilers. Syngas is usually recovered to provide heat for the pyrolysis process itself, achieving energy self-sufficiency. When there is surplus energy, it can be used for power generation or heating.
Batch pyrolysis equipment is highly advantageous for remote areas, small and medium-sized hospitals, or emergency situations. Pyrolysis equipment enables on-site treatment of medical waste, avoiding the high risks and costs associated with long-distance transportation. 
