The choice of process generally depends on the hospital’s size, nature, and wastewater discharge destination. There are four main types of processes: primary treatment with enhanced treatment effects, secondary treatment, simplified biological treatment, and advanced treatment. Hospital wastewater treatment typically involves engineering design, construction, and acceptance procedures. Treatment facilities require a certain period of trial operation before the treatment effect can reach the expected goals. Chemical treatment requires a one-month trial operation, while secondary biological treatment requires more than three months. Therefore, small general hospitals (mainly including urban community health service centers and township health centers) urgently need to find a technical solution (equipment) that requires less investment, has a shorter construction period, and ensures safe and reliable compliance.
1. Primary Treatment: The typical primary treatment process for hospital wastewater is primary sedimentation followed by toxicology. This process is suitable for hospitals whose wastewater discharges into municipal sewers, especially some general hospitals.
2. Secondary Treatment: Secondary treatment is usually biological treatment. Commonly used methods include: biological rotating disc method, biological contact oxidation method, jet aeration method, oxidation ditch method, and tower biological filter method. These technologies all belong to the biological oxidation method, typically utilizing aeration methods such as forced draft aeration and mechanical aeration to promote the proliferation of microorganisms such as fungi in the wastewater, thereby adsorbing and oxidizing organic matter and other harmful substances in the wastewater. Secondary treatment processes are suitable for hospital wastewater discharged into surface water bodies, and can comprehensively treat biological pollution, physicochemical pollution, and toxic and harmful substances in the wastewater.
3. Simplified Biological Treatment The simplified biological treatment process is a wastewater treatment process centered on “biogas purification pond → disinfection,” primarily used for wastewater treatment in hospitals in remote mountainous areas and economically underdeveloped regions. Its biogas purification pond includes three areas: a solid-liquid separation zone, an anaerobic filter, and a sedimentation filtration zone. These zones respectively handle the removal of suspended solids, adsorption of colloids and dissolved substances, and degradation of residual organic pollutants, ultimately ensuring effluent quality through sedimentation filtration.
4. Advanced Treatment
4.1 Treatment typically employs a combination of physical-chemical and biological methods. The main processes include: Flocculation and sedimentation (physico-chemical) + hydrolysis and acidification (biological) + advanced oxidation (biological) + disinfection – achieving discharge standards.
4.2 Flocculation and sedimentation (physico-chemical) + hydrolysis and acidification (biological) + MBR (biological) + disinfection – achieving discharge standards.
4.2.1 Physical-chemical treatment: This primarily involves adding flocculants, coagulants, and other chemical agents to the wastewater to transfer harmful substances to the sludge, thus achieving the desired effect through sludge treatment.
4.2.2 Biological treatment: This involves analyzing the ability of microorganisms in natural water bodies to decompose organic matter. Analysis shows that microorganisms in different environments can decompose different harmful substances. Generally, anaerobic bacteria + aerobic bacteria cultivation is used, i.e., hydrolysis and acidification and advanced oxidation.
