Medical wastewater is highly polluted. Instruments help improve wastewater reuse rate

Water pollution is mainly caused by pollutants produced by human activities, which include mining pollution sources, industrial pollution sources, agricultural pollution sources and domestic pollution sources. Although hospital sewage accounts for a small proportion of domestic sewage, during the operation of hospitals, it is inevitable to produce wastewater with direct or indirect infectiousness, toxicity and other harmful effects. Medical sewage containing pathogenic microorganisms has spatial pollution. , acute infection, latent infection and other characteristics, if they are directly discharged into urban sewers without disinfection, inactivation and other harmless treatments, it will often cause water and soil pollution, and in serious cases, it will cause various diseases, leading to Outbreaks of water-borne infectious diseases.

In March this year, the Beijing Water Administration Supervision Brigade successively launched special law enforcement operations against 55 medical institutions in the six districts of the city. The investigation results showed that 25 medical institutions had drainage water quality exceeding the standard, and another 4 medical institutions had drainage water without a license. In the water quality test, it was found that during this special inspection, a medical institution The bacterial flora exceeded the standard by 1,400 times. If you eat food with excessive microorganisms, you will easily suffer from intestinal diseases such as dysentery, which may cause vomiting, diarrhea and other symptoms, endangering human health and safety.

Water shortages and accidents caused by pollution continue to occur, which not only causes factories to stop production, reduce agricultural production or even eliminate harvests, but also causes adverse social impacts and large economic losses, seriously threatening It affects the sustainable development of society and threatens human survival. Therefore, medical wastewater containing chemicals, radioactive wastewater and pathogens must go through medicalsewage treatment equipment It can be discharged after treatment. Especially the sewage discharged from infectious disease wards such as hepatitis must be disinfected before being discharged.

For sewage treatment in general hospitals (without infectious disease wards), the process of "pretreatment → first-level intensive treatment → disinfection" can be used. Particles carrying viruses and germs are removed through coagulation and sedimentation (filtration). An automatic grille is set up in front of the regulating pool. A lifting pump is installed in the regulating pool. The sewage is liftedAfter rising, it enters the coagulation sedimentation tank for coagulation and sedimentation. The effluent from the sedimentation tank enters the contact tank for disinfection and is discharged up to standard. Infectious disease hospitals (including general hospitals with infectious disease wards) and general hospitals that discharge into natural water bodies use a sewage treatment process of aerated biological filters + chlorine dioxide disinfection. The process is that the raw sewage first passes through a grille to remove floating matter, and then passes through The sedimentation tank separates mud, sand and other particulate matter, and after uniform adjustment, it is pumped to the BAF for biological treatment. The effluent is disinfected by chlorine dioxide and discharged up to standard. The backwash effluent flows back to the sedimentation tank, and the sewage after sedimentation is recycled.

With the advancement of science and technology, wastewater can also be a precious resource and must be utilized to the greatest extent. Improving the recycling rate of medical wastewater can not only reduce pollutant emissions, but also save limited water resources. With the increasing shortage of water resources and the increasing urgency of environmental pollution control, the use of advanced technologies, processes and equipment to treat wastewater before discharging it, increasing the number of water cycles and improving the reuse rate of water resources will be the development of wastewater reuse trend.

　(Original title: Highly polluted medical wastewater, instruments help improve wastewater reuse rate)