The hazards of hospital wastewater

The sources and components of hospital wastewater are complex and highly hazardous. The main sources are sewage discharged from the hospital's diagnosis and treatment rooms, laboratories, wards, laundry rooms, X-ray photography rooms, and operating rooms. Wastewater contains a large amount of pathogenic bacteria, viruses, and chemical agents, which have the characteristics of spatial pollution, acute infection, and latent infection. If hospital sewage containing pathogenic microorganisms is discharged into urban sewage pipes or environmental water bodies without disinfection treatment, it often causes water pollution, leading to various diseases and infectious diseases, seriously endangering people's health.

Principles of Hospital Wastewater Treatment

1) Principle of whole process control. Control the entire process of hospital wastewater generation, treatment, and discharge.
2) Principle of reduction. Strictly implement the hospital's internal hygiene and safety management system, and strictly control and separate sewage and waste sources. Domestic sewage and ward sewage are collected separately in the hospital, that is, source control and clean sewage separation. It is strictly prohibited to dispose of hospital sewage and waste into the sewer system at will.
3) Principle of on-site handling. To prevent pollution and harm during the transportation of hospital sewage, on-site treatment must be carried out in the hospital.
4) Classification guidelines. Classify and guide hospital sewage treatment based on hospital nature, scale, sewage discharge destination, and regional differences.
5) The principle of combining compliance with risk control. Comprehensively consider the basic requirements for sewage discharge standards in comprehensive hospitals and infectious disease hospitals, while strengthening risk control awareness, and improving the ability to respond to emergencies from the aspects of process technology, engineering construction, and supervision and management.
6) The principle of ecological security. Effectively removing toxic and harmful substances from sewage, reducing the production of disinfection by-products during the treatment process, and controlling excessive residual chlorine in the effluent to protect ecological environment safety.

Brief Explanation of Medical Sewage Treatment Process

Medical wastewater is collected in the living area and enters the septic tank for initial sedimentation. It then enters the regulating tank through a grid well for uniform mixing. As the wastewater may contain some large suspended solids, a grid is installed to remove them before entering the regulating tank, which can effectively reduce the subsequent biological treatment load and prevent large suspended solids from blocking the subsequent treatment equipment.

The wastewater treated by the grid flows automatically into the regulating tank. Anaerobic bacteria are introduced into the regulating tank to acidify and degrade the organic matter in the wastewater. After sedimentation, homogenization, acidification, and degradation in the regulating tank. The pump is lifted into the integrated treatment system of activated sludge method. The biochemical method mainly adopts a series process of acidification hydrolysis aerobic oxidation. The purpose of acidification hydrolysis is to hydrolyze and acidify certain high molecular weight substances and soluble substances with poor biodegradability in the wastewater, degrade them into small molecular weight substances and soluble substances, and create conditions for subsequent aerobic biochemical treatment. The aerobic oxidation process adopts the biological contact oxidation method, which is one of the commonly used aerobic biological treatment methods for large and medium-sized wastewater due to its ease of management, low sludge production, resistance to sludge expansion, and low operating costs. At the same time, the sludge generated by aerobic biochemical treatment is partially refluxed to the facultative biochemical section through the sedimentation tank to increase the microbial content.

After biochemical treatment, the water flows into the sedimentation tank and undergoes solid-liquid separation. After entering the clean water tank and being disinfected, it meets the discharge or reuse standards. Part of the separated sludge flows back into the biochemical system, while the remaining sludge is discharged into the sludge concentration tank.