Shen ChangHong Original title: how to deal with new crown medical sewage? Expert interpretation!
Time: 2020-02-07 11:22 source: China Science Daily WeChat official account.
The novel coronavirus pneumonia was detected in the stool of the third people's Hospital in Shenzhen recently.
Although it can not prove that the virus is still infectious, how to treat and avoid secondary pollution of medical sewage related to new coronavirus has become an important issue.
In general, how to deal with medical sewage? In view of this epidemic situation, what should be paid attention to in hospital sewage treatment?
China Science News interviewed sun Xiaohang, member of the water affairs technical committee of Beijing control, and Li Yongjian, director of the water ecology research office of the Institute of ecology, Zhejiang University.
China Science Daily: novel coronavirus is still active in the feces of infected people recently. Experts and experts at home and abroad still need to know what special procedures are needed to deal with such waste water and waste water.
Sun Xiaohang: Although the tolerance, biological activity and transmission law of the new coronavirus in different media have yet to be studied, considering its strong infectivity, it is necessary to carry out "suspect the crime from the existence" and strengthen the protection from a conservative perspective.
According to the U.S. Environmental Protection Agency (EPA), coronaviruses are enveloping viruses, which means they are one of the most easily killed viruses by disinfectant products. Moreover, this kind of virus is highly similar to SARS CoV virus, so in addition to the standard of sewage pretreatment in the hospital under normal conditions, we can use chlorine containing agents (such as liquid chlorine, sodium hypochlorite, chlorine dioxide, etc.) and ozone, ultraviolet and other joint disinfection to the hospital wastewater.
In addition, considering that the new coronavirus can be transmitted through the respiratory tract through droplets and aerosols, it is necessary to attach great importance to the ventilation and exhaust treatment in the infectious ward, sewage and solid waste treatment process. The drainage and sewage pipes should not be equipped with conventional exhaust valves and maintenance wells. The pipes should be suction and filtration with negative pressure in the whole process and closed system as far as possible, and the exhaust gas should be disinfected after t
Li Yongjian: according to the national standard of the people's Republic of China gb18466 discharge standard of water pollutants for medical institutions, the sludge from grid slag, septic tank and sewage treatment station is hazardous waste and shall be treated as hazardous waste.
But for this kind of waste, at present, there is no clear unit in China to collect and post-treatment. Generally, it is treated as ordinary solid waste after dosing and disinfection treatment in sewage station.
It should be noted that there is a certain risk in this treatment method, because it is difficult for bacteria and viruses in sludge, grid slag and feces to be completely and effectively disinfected in the sewage station.
China Science Daily: medical wastewater is special. Do you need some special treatment methods?
Li Yongjian: medical wastewater treatment is generally divided into primary treatment + disinfection and secondary treatment + disinfection. Hospital wastewater discharge must be disinfected and then incorporated into the municipal pipe network for discharge and drainage. For infectious disease hospitals, it is recommended to adopt secondary treatment + advanced treatment + disinfection treatment.
Sun Xiaohang: novel coronavirus, the standard of hospital wastewater treatment and technical specification for wastewater treatment are recommended for reference to general medical wastewater. The new standard for the treatment of infectious diseases such as new coronavirus and other wastes is considered in the highest standard of micro biological control. HJ2029-2013: 1. In the process of treatment, fully sealed and high standard processes such as membrane treatment, multi-stage disinfection of chloride and ozone should be used as far as possible, and small incinerators should be used as far as possible to treat sludge and medical waste.
Water pollutant emission limit of infectious diseases and tuberculosis medical institutions (daily average)
China Science Daily: what should be paid attention to in the transportation process of medical waste water? What kind of standardized process is there?
Sun Xiaohang: according to the existing environmental protection laws and regulations in China, medical wastewater should be treated at the source in principle, and discharged after reaching the comprehensive discharge standard of sewage.
If the sewage treatment facilities of the hospital are difficult to be built immediately in special period, the infectious disease wastewater and waste need to be transferred. In principle, it must be disinfected at the source at least, and then transported to the sewage plant for treatment in accordance with the requirements of the treatment of hazardous wastes after meeting the microbial indicators in the discharge standard of water pollutants for hospital institutions.
At the same time, it is suggested to collect feces and sewage by classification. Solid waste shall be treated in accordance with the relevant national standards for medical waste.
China Science Daily novel coronavirus emergency medical treatment technology plan (Trial Implementation) issued by the Ministry of ecology and environment in February 1st. What's your comment on this?
Li Yongjian: first of all, according to the national standard of the people's Republic of China gb18466 discharge standard of water pollutants for medical institutions, medical institutions of infectious diseases and tuberculosis should disinfect the waste gas discharged from the sewage treatment station.
In addition, in the emergency treatment scheme in the technical scheme, the disinfection method adopted shall be carried out according to the SS concentration in the sewage. The requirements for the concentration of suspended matter in sewage are also high. The concentration of suspended matter in sewage is in accordance with the requirements of gb18466. In addition, considering that chlorine disinfectant has the function of continuous disinfection and that ultraviolet and ozone disinfection do not have the ability of continuous disinfection, it is recommended to use chlorine containing disinfectants. The common chlorine containing disinfectants are dichloroacetonitrile uric acid (chlorine powder), 10% sodium hypochlorite solution, chlorine dioxide and liquid chlorine.
Sun Xiaohang: according to the epidemic situation, it is of great significance for the Ministry of environmental protection to issue technical guidance documents in a timely manner.
But in the process of implementation, it needs to be implemented according to the epidemic situation, material reserves and process conditions in different regions, and the final evaluation standard is to ensure the effluent standard and staff safety.
China Science Daily: what other suggestions do you have for sewage and sludge treatment during the epidemic?
Sun Xiaohang: in this period of time, due to the lack of disinfectants, carbon sources, coagulants and other materials, it is difficult to transport them; the risk of sludge disposal in sewage plant is very high, and many enterprises downstream of sludge disposal stop production. It is suggested that government agencies should give priority to the supply of water and sewage plant materials on the premise of ensuring medical resources at present.
In the abnormal period, on the premise that the microorganism index of the sewage plant reaches the standard, it is suggested that the environmental protection department should appropriately relax the assessment of total phosphorus, total nitrogen and sludge concentration.
Li Yongjian: the sewage is better to be treated. Generally, large hospitals and infectious disease hospitals have complete sewage treatment facilities. As for sludge, it must be treated as hazardous waste according to the national requirements, but at present, there is no hazardous waste organization that collects hospital grid slag and sludge and processes them. Some cities have red head documents, and the sludge grid slag will be treated as common solid waste and transported out for treatment.
It is suggested that during the epidemic period, the sludge tank should be collected for post disinfection treatment and then transported out for treatment. The grid slag produced by the sewage station must be disinfected and transported out for treatment. Meanwhile, the operators of the sewage station must take protective measures.
reference:
1. Gb18466-2005 discharge standard of water pollutants for medical institutions
https://wenku.baidu.com/view/2434524db5daa58da0116c175f0e7cd184251828.html
2. Technical code for hospital wastewater treatment engineering (hj2029-2013)
http://www.doc88.com/p-9833371986550.html
3. design criteria for novel coronavirus infectious diseases emergency medical facilities
