Lhasa sewage treatment equipment - hospital sewage

Characteristics of hospital wastewater

Hospital wastewater contains some special pollutants, such as drugs, disinfectants, diagnostic agents, detergents, as well as a large number of pathogenic microorganisms, parasite eggs, and various viruses (such as roundworm eggs, hepatitis viruses, tuberculosis bacteria, and dysentery bacteria). In addition, the wastewater in hospitals with isotope diagnosis and treatment rooms also contains radioactive substances such as radium-226, phosphorus, gold-198, * 131, etc. Compared with industrial wastewater and domestic sewage, it has the characteristics of small water volume and strong pollution. If left unchecked, it will inevitably pollute water sources and spread diseases.

2.1 Biological oxidation method

Biological oxidation method, also known as activated sludge process, is a commonly used traditional treatment method for various types of wastewater. By using air blowing aeration, mechanical aeration, etc., a large number of filamentous bacteria, fungi and other microorganisms in the sewage are propagated. These microorganisms have the ability to adsorb and oxidize harmful substances in the sewage, thereby reducing the COD and BOD of the sewage and achieving purification effect. Some sewage treatment plants also use a combination of anaerobic and aerobic methods. During anaerobic processes, anaerobic microorganisms reproduce, nitrify, and adsorb harmful substances in water. Its disadvantage is that it generates a large amount of activated sludge and requires sludge treatment, which prolongs the treatment process, increases engineering costs, and causes secondary pollution to the air during the aeration process. There are many examples of this in China, and Daqing Fifth Hospital is one of them (drum aeration method). The commonly used biological oxidation methods include biological contact oxidation, biological rotary disc method, tower biological filter method, jet aeration method, and oxidation ditch method.

2.2 Chemical reagent method

The chemical agent method involves adding an appropriate amount of chemical agents to wastewater to oxidize harmful substances and achieve coagulation, adsorption, and precipitation. This method has gradually developed over the past thirty years after traditional biochemical methods.

① Yelv: Liquid * is widely used for disinfection of tap water and hospital sewage due to its strong disinfection ability and low price. But * gas is a yellow gas with a pungent odor that cannot be produced anytime and anywhere. Storage and chlorination equipment are necessary. The equipment for adding liquid * has a complex structure, is prone to corrosion, and poses a high level of danger, therefore its use is restricted in urban or densely populated areas.

② Sodium hypochlorite solution: Sodium hypochlorite is one of the original disinfection methods. This method has convenient raw material sources, stable products, easy transportation, low equipment investment, low operating costs, easy management, safety, reliability, and will not produce sludge due to disinfectants. It is widely used. However, sodium hypochlorite has weak disinfection ability and generates waste residue during the treatment process, which is gradually being replaced by other products.

③ Ozone method: Ozone is a strong oxidant, and adding an appropriate amount of ozone to wastewater oxidizes microorganisms and various metal ions in the water. This method is more effective in treating hospital wastewater and has less secondary pollution. The disadvantage is that it requires multiple supporting equipment, requires a large one-time investment, requires a large amount of equipment maintenance, consumes a large amount of electricity, and increases the annual operating costs.

3.1.1 Characteristics of CASS process

The CASS pool has reduced its volume and achieved better results through technological innovation and optimized design. This method involves continuous inflow without aeration, resulting in a high concentration of organic matter in a state of hypoxia and anaerobic conditions, which inhibits the growth of aerobic bacteria and controls the sludge from expanding. The main reaction zone is divided into two parts: anoxic and aerobic, with periodic aeration, sedimentation, and skimming. During the sedimentation stage, no water is introduced, eliminating potential hydraulic interference and improving sludge characteristics and effluent quality. The biochemical treatment method for hospital wastewater with complex components, containing various pathogens, viruses, parasite eggs, and some harmful substances, and with large changes in water quality and quantity, has stronger adaptability and better treatment effect. It is an ideal method for biochemical treatment of hospital wastewater

① The construction cost is low. The biodegradation, sludge settling, and wastewater discharge of CASS are all carried out in the same tank, without the need for regulating tanks, secondary sedimentation tanks, and sludge return equipment, which can greatly save investment, reduce land use, and lower operating costs. Generally, construction costs can be saved by 10% to 25%, and the land area can be reduced by 20% to 35%.

② Low operating costs. Due to periodic aeration, the concentration of dissolved oxygen in the tank decreases during the sedimentation and drainage stages. During aeration, the oxygen concentration gradient is large, the transfer efficiency is high, and the energy-saving effect is significant. Operating costs can be saved by 10% -25%.

③ High organic matter removal rate and good effluent quality. The CASS method not only effectively removes various organic pollutants from wastewater, but also has good denitrification and phosphorus removal functions. Make the investment in secondary treatment reach the water quality of tertiary treatment.

④ The CASS process is highly capable of achieving aerobic, anoxic, and anaerobic states in delayed aeration and cyclic circulation. For the treatment of hospital sewage, it is necessary to consider the presence of viruses and pathogenic bacteria that can infect patients. Therefore, the treatment method of ordinary sewage purification tanks cannot be used. Anaerobic and facultative combined treatment should be adopted, and a series of physical, chemical, and biological principles should be used to precipitate, decompose, engulf, and kill organic matter, bacteria, and viruses in infectious disease sewage. The CASS method can effectively meet this requirement.

Best Friends The new type of underwater aeration equipment replaces the traditional blowing aeration method, with flexible use, simple system, and no noise pollution.

⑥ The management unit operates reliably. There are relatively few types and quantities of equipment in sewage treatment plants, and the control system is relatively simple. Floating automatic lifting skimming devices and special decanters are used to discharge water during the inlet process, and the lifting of the water permeable device is automatic. Ensure stable water output.

3.2 Chlorine dioxide disinfection

3.2.1 Characteristics of Chlorine Dioxide Disinfection

Chlorine dioxide is an efficient, broad-spectrum, safe, fast, multifunctional, long-lasting, and easy to store and use disinfectant. It is classified as a safe disinfectant (A1) by the World Health Organization (WHO), and has been approved by the US Environmental Protection Agency (EPA) and the US Food and Drug Administration (FDA) for use in hospitals, food processing, and other departments.

The commercial chlorine dioxide products produced domestically and internationally are mainly stable chlorine dioxide solutions, and there are also a small number of solid chlorine dioxide products such as slow-release bulk, gel like particles, microencapsulated powders, etc. In recent years, chlorine dioxide method has become very popular in the domestic sewage treatment industry and has shown good results in hospital sewage treatment. The advantages of using chemical chlorine dioxide disinfection for treating hospital wastewater are:

① ClO2 can kill all microorganisms, including bacterial colonies, cell spores, fungi, mycobacteria, and viruses. It can effectively destroy trace organic pollutants in water, such as benzo [a] pyrene anthraquinone, lv [a] pyrene, phenols, chlorophenols, hydrogen sulfide, and organic sulfides. It can effectively oxidize some reduced metal ions in water, such as Fe2+, Mn2+, Ni2+, etc. It is less affected by pH, has a killing effect on algae, and can also reduce the color, turbidity, and odor of aqueous solutions. Its effect is 5 times that of sodium hypochlorite. Not forming significant organic halides in sewage treatment is an ideal choice for hospital sewage treatment.

② Chlorine dioxide is more effective in disinfecting viruses than ozone and Yelv. It reacts quickly with sewage and has a contact time that is 1/2-1/4 of chlorine, which can be shortened from 1 hour to 0.5 hours. The contact tank can be reduced to half of its original size, greatly saving investment.

3.2.2 Processing effect

Jiangsu Cancer Hospital is a tertiary Grade A specialized hospital with over 600 beds. Approximately 500 tons of sewage are discharged daily. Using a chemical chlorine dioxide generator to treat hospital wastewater. The use of chlorine dioxide generators does not require further biochemical treatment, and can achieve emission standards for bacterial count, COD, and other indicators, greatly saving the investment and daily operating costs of hospital sewage treatment facilities. The treated hospital wastewater meets the discharge standards.

To determine the hospital sewage treatment process, it is not only necessary to achieve the purpose of disinfection and sterilization, but also to consider the requirements of sewage discharge and the functional zoning of the receiving water environment for water quality. Hospital sewage should comply with the "Discharge Standards for Water Pollutants in Medical Institutions" (GB18466-2005), which puts higher requirements on hospital sewage treatment. According to the standards and related requirements, using chemical chlorine dioxide disinfection or CASS process to treat hospital sewage can adapt well to this change. Compared with corresponding treatment methods, it has good effects, less investment, convenient management, low operating costs, practical technology, and is technically and economically competitive. It is currently the preferred method for hospital sewage treatment that integrates social, economic, environmental, and ecological benefits.

Lhasa sewage treatment equipment - hospital sewage