Hospital sewage refers to the sewage discharged from hospitals (general hospitals, specialized hospitals, and other types of hospitals) into the natural environment or urban pipelines. The water quality varies with the nature, scale and location of different hospitals. The functions, facilities, and personnel composition of each department in the hospital are different. The main departments and facilities that produce sewage are: diagnosis and treatment rooms, laboratories, wards, laundry rooms, X-ray image printing, animal rooms, isotope treatment and diagnosis, operating rooms and other drainage; Domestic sewage discharged by hospital administration and medical staff, canteens, single dormitories, and family dormitories. The composition and volume of sewage produced by different departments are different, such as heavy metal wastewater, oily wastewater, printing wastewater, radioactive wastewater, etc. Moreover, the sewage produced by different types of hospitals is also very different. The discharge of hospital sewage is more complicated than general domestic sewage. The amount of sewage discharged from each hospital bed is about 200-1000L per day.