Hospital wastewater treatment system

Why should we build a wastewater treatment system for hospitals?

The number of patients and number of hospital beds is increasing due to population growth or some hospitals and medical facilities increasing their capacity to meet medical examination and treatment needs, leading to the amount of wastewater and garbage at some places. The number of hospitals increased. Therefore, the hospital's wastewater treatment system needs to be installed, repaired and upgraded to suit the scale of development, health care needs of the people and ensure technical regulations and standards. environmental country.

Outstanding advantages:

The wastewater treatment system helps quickly reduce the concentration of pollution in wastewater before being discharged into the outside environment. As the latest, most advanced technology...the system possesses many outstanding advantages compared to conventional treatment systems: 

• Low operating costs.
• Easy operation with control system.
• Consumes less chemicals
• Easy to install, easy to maintain
• High treatment efficiency: wastewater treatment meets QCVN 28:2010/BTNMT, level B.
• High flexibility: Treatment technology can withstand high pollution loads, thus being safe when there are fluctuations in flow and pollution concentration.

Learn about the characteristics of wastewater sources from hospitals

Harmful effects of hospital wastewater

Hospital wastewater is wastewater generated from hospitals and wastewater contains harmful toxins such as pharmaceutical residues, disease-causing bacteria, viruses, and harmful chemicals.

Untreated hospital wastewater contains many sources of pathogens, chemical and physical substances that are harmful to human health and the environment. Therefore, treating hospital wastewater before discharging it into the environment is necessary and needs to be prioritized during the process of hospital construction and development.

Sources of hospital wastewater generation

Hospital wastewater includes two sources: medical wastewater and domestic wastewater.

• Medical wastewater : blood, body fluids, surgery, obstetrics and gynecology, wastewater from laboratories, wastewater from cleaning patient wounds, preparing drugs, etc.
• Domestic wastewater : washing clothes of patients, hospital staff and workers, towels, blankets for hospital beds, cleaning, cleaning patient rooms, washing dishes, chopsticks, food...

The characteristics of these types of wastewater are that they contain many impurities, chemicals (such as formaldehyde, mixed chemicals, etc.), organic substances, nutrients, and detergents (such as salts of acids). higher fats) and especially bacteria, viruses, parasites (such as salmonalla, shigella, gastrointestinal viruses, etc.), various biological pathogens in blood, pus,… and even including toxic radioactive substances

Parameter values ​​and pollutants are specified in QCVN 28: 2010/BTNMT National Technical Regulation on Medical Wastewater

Note:

• KPH: Not detected
• Parameters Total radioactivity α and β only apply to medical examination and treatment facilities that use radioactive sources.

In Table 1:

Column A specifies the C values ​​of parameters and pollutants as a basis for calculating the maximum allowable value in medical wastewater when discharged into water sources used for domestic water supply purposes.

• Column B specifies the C values ​​of parameters and pollutants as a basis for calculating the maximum allowable value in medical wastewater when discharged into water sources not used for domestic water supply purposes.
• Medical wastewater discharged into the general sewer of residential areas shall apply the value C specified in column B. In case medical wastewater is discharged into the collection system leading to the centralized wastewater treatment system, it must be Disinfection, parameters and other contaminants apply according to the regulations of the unit managing and operating the centralized wastewater treatment system.

Technological process diagram of hospital wastewater treatment system

 

1. Collection tank: 

The collection tank is responsible for concentrating hospital wastewater. Before the water reaches the collection tank, it passes through a mesh to remove coarse trash and large substances in the wastewater. Then water from the Collection Tank is pumped to the Equalization Tank.

2. Air conditioning tank: 

• Because the properties of domestic wastewater are different from medical wastewater and vary greatly depending on the number of people using the water, it is necessary to build an equalization tank.
• The regulating tank is responsible for regulating the flow and stabilizing the concentration before sending wastewater to the downstream units, avoiding fluctuations in the content of organic substances in wastewater that affect the operation of the wastewater treatment plant. microorganisms in the biological treatment process, avoid overloading the water treatment system to create conditions for the downstream works to stabilize and achieve high treatment efficiency. 
• To avoid sedimentation, reduce odors, and stabilize concentrations, an air blowing system will be installed in the conditioning tank. 
• From the wastewater treatment tank, the wastewater is pumped at a stable flow into the anaerobic biological tank.

3. Anaerobic biological tank: 

Wastewater after being conditioned and stabilizing the flow will be pumped to the anaerobic tank. Here, thanks to the decomposition of organic substances in an anaerobic environment, anaerobic microbial strains grow, develop, and convert pollutants in wastewater into nutrients for cells, reducing pollution concentration in wastewater.

After anaerobic treatment, wastewater is directed to the downstream treatment facility.

4. Anoxic biological tank:

- Domestic wastewater contains a large amount of nutrients Nitrogen and Phosphorus, these are two nutrients that cause eutrophication of receiving sources and negatively affect the water environment, so they need to be treated. removed before discharging into receiving sources.

- In the Anoxic anoxic biological tank, under anoxic conditions, anoxic microorganisms develop and process N and P through the process of Nitrification and Phosphoril.

5. Aerobic biological tank:

The main function of the aerobic biological tank is to convert ammonium in wastewater into Nitrite and Nitrate. Part of the amount of nitrate produced during the aerobic process will be circulated back to the anoxic tank to carry out the denitrification process, part will be retained in the activated sludge and settled in the biological sedimentation tank. The nitrification and denitrification process will reduce the concentration of ammonium and nitrate in wastewater, so the treated wastewater meets connection standards. The nitrification process is expressed by the equation below:

The process of reducing organic substances such as BOD and COD is carried out along with the process of removing N and P nutrients.

6. Biological sedimentation tank

- Biological sedimentation tank is a tank that separates biological sludge from clean water after treatment.

- The mixture of sludge and wastewater leaves the aerobic biological tank and overflows into the biological sedimentation tank to conduct the water and sludge separation process. The sludge flocs will settle to the bottom of the settling tank and will be circulated by the sludge pump to the Aerotank to maintain the activated sludge concentration when necessary. If there is excess sludge in the tank, the sludge will be pumped and discharged into the sludge tank.

- The clear water is concentrated on the surface of the settling tank, collected by a surface water collection pipe system, the water flows into the disinfection tank itself.

- The excess sludge is pumped and discharged into the sludge tank, the sludge separation water is circulated back to the equalization tank and the wastewater treatment process continues. The excess sludge after separating a portion of the water will be collected and processed by the sludge collection unit.

7. Sludge Storage Tank: A tank that receives excess sludge

8. Disinfection Tank

The clear water after settling is collected and led to the disinfection tank. At the disinfection tank, disinfectant chemicals (chlorine or ozone) are used to disinfect and kill coliforms in wastewater before being discharged into the receiving source.
Treated wastewater meets discharge standards according to QCVN 28:2010/BTNMT, Column B.