20 years focusing on recycling
Medical waste refers to medical and health institutions in the medical, preventive, health care and other related activities generated in direct or indirect infectious, toxic and other hazardous waste. Medical waste is divided into five categories: infectious waste, pathological waste, injurious waste, pharmacological waste and chemical waste, all of which are currently included in the National Hazardous Waste List.
Because medical waste itself has special properties, it also requires special treatment methods to eliminate its hazardous and dangerous nature. Currently, the following medical waste treatment methods are commonly used at home and abroad.
I. Medical Waste Sanitary landfill
Sanitary landfill method is to bury the waste into the ground, through the long-term decomposition of microorganisms, so that it decomposes into harmless substances. If the landfill system of medical waste is not impermeable, various toxic substances, pathogens, radioactive substances, etc. will seep into the soil with rainwater, and harmful substances will enter the human body through the food chain, endangering human health. Therefore, the sanitary landfill site needs to be scientifically selected and laid with clay, high-density polyethylene and other materials impermeable layer, must also set up landfill gas collection and output pipeline, so the use of landfill treatment method must be very careful, must be in accordance with the relevant provisions of the medical waste for strict pretreatment.
2, the high-temperature Medical Waste incineration
Incineration treatment is a chemical process of deep oxidation, in the role of high-temperature flame, incineration equipment within the medical waste after drying, ignition, incineration of the three stages will be transformed into residue and gas, medical waste in the infectious and harmful substances in the incineration process can be effectively destroyed. Incineration technology is suitable for a variety of infectious medical waste, incineration requires a high and stable furnace temperature, good oxygen mixing conditions, sufficient gas residence time and other conditions, while the need for the final discharge of smoke and residue for environmentally sound disposal.
3. Medical Waste Autoclave
Pressure steam sterilization treatment method is the principle of medical waste in high temperature, high-pressure process conditions run for more than 20 min, pressure steam penetrate the interior of the object, so that the microbial protein coagulation denaturation and killed; it should be noted that the use of this treatment method must be crushed medical waste treatment, crushing can be before or after the cooking, but the State Environmental Protection Administration announced the "Medical Waste High-Temperature Steam This method is not suitable for the treatment of pathological waste, such as human tissue and animal carcasses, and is not efficient for the treatment of drugs and chemical waste.
4. Medical Waste Pyrolysis Method
Pyrolysis is the process of extracting fuel oil, grease and gas by using the instability of organic matter in garbage and heating and distilling it under the condition of anaerobic or anoxic so that the organic matter will produce thermal cracking and form various gases, liquids and solids after condensation.
5. Chemical disinfection Medical Waste method
The essence of the chemical disinfection method is to mix the crushed medical waste with a certain concentration of disinfectant (sodium hypochlorite, peroxyacetic acid, glutaraldehyde, ozone, etc.) and ensure that it has sufficient contact area and time with the disinfection agent, and the organic matter is decomposed and microorganisms are killed in the disinfection process. The maximum contact between disinfectant and medical waste is a prerequisite to guarantee the treatment effect. Shear-type crushing equipment is used to increase the degree of fragmentation and ensure that the disinfectant penetrates. The chemical disinfection method is suitable for the treatment of liquid medical waste and pathological waste, but recently it is also gradually used for the treatment of medical waste that can not be sterilized by heating or wetting.
6. microwave sterilization treatment method
Microwave disinfection technology is a new type of medical waste treatment technology, but is still limited to small batches, intermittent treatment of medical waste, can not meet the requirements of high-volume, continuous treatment of medical waste.
Dry thermal shredding technology, irradiation technology, plasma method and electric arc furnace technology are very rare in practical applications and are not described in detail in this paper.
Comparison of 6 Ways of medical waste treatment.
Sanitary landfill technology is generally used as a means of supporting the final treatment of other technologies, rarely used alone.
High-temperature incineration method for all types of medical waste, incineration of waste volume and weight significantly reduced, disinfection and sterilization and pollutant removal effect are good, and mature technology; but the construction and operation costs are very high, will produce dioxins and other highly toxic substances and other harmful gases.
The autoclaving method has low investment, low operating costs, and low residue hazard; however, it is prone to malodor, and possible air pollution emissions, and must crush medical waste to a size less than 50 mm.
Chemical sterilization method is divided into dry and wet, its process equipment and operation are simple and convenient, good deodorization effect, rapid disinfection process, where the dry type needs to be used together with crushing treatment, while the wet type will have waste liquid and exhaust gas generation.
At present, the country's 261 large and medium-sized cities have established their own medical waste disposal in, to achieve the centralized disposal of medical waste in the region. Among them, more than 140 disposal centers using the high-temperature incineration method, more than 120 disposal centers use autoclaving method, other microwave sterilization, dry chemical and pyrolysis methods have several. It is worth noting that the market share of the autoclaving method is still growing.