Hospital wastewater treatment

Sources of hospital wastewater

Medical wastewater is wastewater generated from medical examination and treatment facilities including:

•  State, private, international hospitals,..
•  General, specialized, private clinics
•  Medical and cosmetic center
•  Medical and pharmaceutical research and training facility
•  Drug manufacturing facility

Sources of hospital wastewater

Content of hospital wastewater pollution?

Although it accounts for a small part, medical examination and treatment wastewater has very complex pollution components, specifically as follows:

Table of pollutant components in medical wastewater

Hospital wastewater treatment process

 

Hospital wastewater treatment needs to be based on the following criteria: Construction area, investment costs and treated wastewater to ensure output meets QCVN 28:2010/BTNMT.

AAO technology combined with MBR is currently the optimal solution to ensure the above three criteria because this technology thoroughly treats waste and infectious pathogens. With a modular design, it is easy to relocate or upgrade. capacity when needed.

Hospital wastewater treatment technology diagram

>A hospital wastewater treatment technology line

Explanation of hospital wastewater treatment technology

Collection tank

Wastewater from the hospital’s general sewer system is led into a collection tank with a stainless steel trash screen with a gap size of 5-10 mm to separate trash and large objects in the wastewater.

Biological tank

AAO technology combines anaerobic (anoxic) and aerobic (oxic) technology.

• • Anaerobic prevention

Suspended microorganisms are combined with a specialized PP substrate buffer to create an anaerobic microbial membrane, increasing the microbial density up to about 20,000 microorganisms/m³ wastewater, ensuring treatment efficiency according to COD and total P up to 75-80%.

Types of anaerobic microorganisms will help quickly decompose indigestible, difficult-to-decompose substances and residues such as: Cellulose, Starch, Chitin, Pectin, Protein, Lipids and some other long-term stable activities found in Hospital wastewater treatment. In addition, anaerobic microorganisms in hospital wastewater treatment also eliminate odors and inhibit bacteria that cause stench.

• •  Prevent lack of air – Anoxic

Medical wastewater after being treated with difficult-to-decompose organic substances in the anaerobic compartment. will be transferred to the anoxic compartment for processing. Here, under anoxic conditions, anoxic microorganisms develop and process N and P through the two processes of Nitrification and Phosphorite and the final result is the release of N₂ to fly up and Partial COD is processed

• • Aerotank

After coming out of the anoxic compartment, pH balancing chemicals are pumped into the conditioning tank. The purpose is to help hospital wastewater treatment always have a stable pH within the threshold of good microbial growth. In the Aerotank, medical wastewater is mixed with aerobic microorganisms thanks to the air supply system. . This process creates favorable conditions for aerobic microorganisms to grow and develop. As a result, BOD in wastewater is significantly reduced and ammonium is converted into nitrate

After passing through the biological treatment tank, the wastewater and sludge mixture is passed through the biological sedimentation compartment to separate the majority of the activated sludge for return to the aerobic and anaerobic compartments. The excess sludge is sent to the sludge tank.

Disinfection tank

The wastewater after the biological sedimentation compartment is fed into the disinfection compartment. The clear water after settling is collected and led to the disinfection tank. Wastewater can be disinfected in two ways:

•  Some disinfection chemicals NaOCl, Ca(OCl)₂ Chloramin B (C6H5SO2NClNa.3H20), ozone are used to disinfect and kill coliforms in wastewater before discharge the sources. Treated wastewater meets discharge standards according to QCVN 28:2010/BTNMT, Column B.
•  Disinfection with MBR ultrafiltration membrane (Membrane Biological Reactor) with pore size 0.3 – 0.5 µm. MBR membranes can eliminate 98% of bacteria in wastewater. Most E.coli bacteria are retained on the filter membrane. In addition to the disinfection function, the MBR surface also concentrates high-density activated sludge to continue to thoroughly treat wastewater. The MBR membrane is backwashed hydraulically according to a pre-set automatic program.

Advantages and disadvantages of the above technology

Advantages

Medical wastewater treatment with AAO technology combined with MBR membrane is an advanced technology that has been commonly applied in Vietnam, Japan, Korea, and Germany, with the following specific advantages:

•  Effective treatment of wastewater with high levels of pollution;
•  Use available sources of microorganisms in wastewater to treat pollutants
•  Takes up little space, can be installed submerged or above ground, can be moved;
•  Fast assembly, compact structure, mobile, can be coordinated with existing treatment tanks;
•  Low power consumption so operating costs are low
•  Highly safe and environmentally friendly…
•  Low chemical consumption

Disadvantages

• High investment costs

Each technology has certain advantages and disadvantages. A suitable technology model must be calculated and selected to best suit the actual conditions of the operating medical facility, taking into account future development. With the combination of advanced treatment methods, the basic wastewater treatment process of some of the above hospitals will be the basis from which designers apply treatment technology to suit each type. specific projects to achieve economic efficiency and still meet waste discharge standards according to QCVN 28:2010/BTNMT.