Water pollution refers to the reduction or loss of the use value of water caused by harmful chemicals, resulting in water that pollutes the environment. According to a survey by global organizations, 80% of various diseases in developing countries are transmitted through drinking unhygienic water, resulting in at least 20 million deaths annually. Therefore, water pollution is known as the "world's killer".

Water pollution is mainly caused by pollutants generated by human activities, including mining pollution sources, industrial pollution sources, agricultural pollution sources, and domestic pollution sources. Although hospital sewage accounts for a small proportion of domestic sewage, it inevitably generates wastewater with direct or indirect infectivity, toxicity, and other hazards during the operation of hospitals. Medical sewage containing pathogenic microorganisms has characteristics such as spatial pollution, acute infection, and latent infection. If it is not disinfected, inactivated, and other harmless treatments, but directly discharged into urban sewers, it often causes water and soil pollution, and in severe cases, can lead to various diseases and outbreaks of waterborne infectious diseases.

In March of this year, the Beijing Municipal Water Administration Supervision Brigade carried out special law enforcement actions against 55 medical institutions in the six districts of the city. The survey results show that 25 medical institutions have exceeded the standard of drainage water quality, and another 4 medical institutions have unlicensed drainage. In water quality testing, it was found that medical institutions exceeded the standard of fecal coliforms by 1400 times during this special inspection. If food with excessive microorganisms is consumed, it is easy to suffer from intestinal diseases such as dysentery, which may cause symptoms such as vomiting and diarrhea, endangering human health and safety.

The continuous occurrence of water shortage and accidents caused by pollution not only leads to factory shutdowns, reduced agricultural production, and even crop failures, but also causes adverse social impacts and significant economic losses, seriously threatening the sustainable development of society and the survival of humanity. Therefore, medical wastewater containing chemicals, radioactive wastewater, and pathogens must be treated by medical wastewater treatment equipment before being discharged, especially the wastewater discharged from infectious disease wards such as hepatitis, which must be disinfected before being discharged.

For sewage treatment in general hospitals (without infectious disease wards), the process of "pretreatment → first level enhanced treatment → disinfection" can be adopted. By using coagulation sedimentation (filtration) to remove particles carrying viruses and bacteria, an automatic grille is installed at the front of the regulating tank, and a lifting water pump is installed inside the regulating tank. The sewage is lifted and enters the coagulation sedimentation tank for coagulation sedimentation. The effluent from the sedimentation tank enters the contact tank for disinfection and meets the discharge standards. Infectious disease hospitals (including comprehensive hospitals with infectious disease wards) and comprehensive hospitals discharging into natural water bodies use a sewage treatment process of aerated biofilter+chlorine dioxide disinfection. The process is that the original sewage is first treated with a grid to remove floating objects, and then separated from particles such as mud and sand in a sedimentation tank. After being adjusted evenly, it is pumped to BAF for biological treatment. The effluent is disinfected with chlorine dioxide and discharged in compliance with standards. The backwashed effluent flows back to the sedimentation tank, and the separated sewage is circulated for treatment.

With the advancement of science and technology, wastewater can also be a valuable resource that needs to be utilized to the fullest extent. Improving the recycling rate of medical wastewater can not only reduce pollutant emissions, but also save limited water resources. In the context of increasingly scarce water resources and urgent environmental pollution control, adopting advanced technologies, processes, and equipment to treat wastewater before discharge, increasing the frequency of water recycling, and improving the reuse rate of water resources will be the development trend of wastewater reuse.