Hospital wastewater is among the most polluted wastewater types, containing chemicals, pharmaceuticals, pathogens, and infectious waste. Its direct discharge into the environment can have serious and irreversible consequences for human health and the environment. Therefore, the use of hospital wastewater treatment plants is crucial.
This article provides a comprehensive overview of the equipment used in hospital wastewater treatment plants and its role in the purification process.
Main components of hospital wastewater treatment plants
1. Detection unit
The first step in any wastewater treatment plant is the removal of coarse solids. Mechanical or manual filters are used to separate waste such as bandages, gloves, syringes, plastic fragments, and other large suspended particles. This prevents blockages in pumps, pipes, and other downstream plant components.
2. Pressure equalization tank
The flow rate and pollutant concentration in hospital wastewater fluctuate throughout the day. A balancing tank serves to equalize the flow rate and pollutant concentration. This tank is equipped with the following:
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Mechanical motors or ventilation systems are used to prevent the deposition of solids.
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Liquid level sensors and automatic control units are used to regulate pump operation
.
Balancing increases cleaning efficiency and stabilizes the operation of the entire system.
3. pH control unit
Hospital wastewater is typically acidic or alkaline. To prevent damage to microorganisms during subsequent treatment, a pH adjustment tank
is required. In this tank, an acid or alkali (e.g., sulfuric acid or sodium hydroxide) is added to the wastewater using a dosing pump to adjust the pH to a value between 6.5 and 8.
4. Device for coagulation and flocculation
In this phase, chemicals such as aluminum sulfate (alum), polyelectrolytes, or iron(III) chloride are used to bind small colloidal particles and form larger particles (agglomerates).
The equipment primarily used in this phase includes:
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chemical injection tank
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High- and low-speed mixers
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Metering pumps are used for precise quality control of materials.
5. Settling basin
The flocs formed in the previous step are transferred to a settling tank, where the solids separate from the water. The sediment collects at the bottom of the settling tank and is then directed to a sludge collection basin. The optimal design of the settling tank’s gradient, retention time, and sludge collection system is crucial.
6. Bioreactor
The biological unit forms the core of every wastewater treatment plant . In this unit, microorganisms use oxygen to break down organic matter in the wastewater. Depending on the type of process, the following methods can be used:
a) Increase in ventilation time
This system uses a fan and a microbubble diffuser to supply bacteria with oxygen . Key components:
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fan
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Disc or lamp publisher
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A bioreactor equipped with a suitable stirring system.
b) MBBR process (Moving Bed Bioreactor).
In this process, a floating plastic carrier medium serves as a nutrient medium for bacterial growth. Aeration sets the carrier medium in motion and increases contact with the wastewater.
Advantages: high efficiency, compact design, and easy maintenance.
c) IFAS process (Integrated activated sludge process with stable membranes)
It is a mixture of activated sludge and stationary filter material, which is widely used in modern hospital equipment.
7. Secondary clarifier
After biological treatment, the wastewater contains activated sludge and suspended solids. At this stage, these particles are separated in a secondary clarifier . A portion of the settled sludge is returned to the reactor to maintain the biomass (recirculation sludge), while the remaining sludge is transferred to a sludge basin.
8. Sterilization unit
Wastewater must be disinfected to kill pathogenic microorganisms and dangerous viruses . The equipment described in this section includes:
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Tank for contact with chlorine or ozone
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Dosing pump for chlorine or ozone generator
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UV chamber (in more advanced systems)
Hospitals often use chlorination or UV light systems to reduce the harmful effects of free chlorine on the environment.
9. Final processing (polishing area)
In some processes, the treated wastewater is passed through sand and carbon filters to remove suspended solids, residual odors, and dyes. The wastewater can then be reused, if needed, for irrigating green spaces or cleaning water tanks.
10. Sludge treatment plant and associated equipment.
Wastewater treatment is only one part of the system; the other is sludge treatment . The sludge collected in the primary and secondary clarifiers is transferred to a sludge thickening tank . The following systems are then used to reduce the sludge volume and moisture content:
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Filter press
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centrifuge
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Drying layer
Finally, the dried sludge is packaged and transported to an approved landfill for disposal.
Control and measuring devices as well as electrical equipment for wastewater treatment plants in hospitals
To ensure automated and reliable operation of the packaging system, various control units are used:
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Electrical control cabinets and programmable logic controllers (PLCs) for controlling ventilation , pumps and material supply.
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Flow, pH, oxygen and level sensors
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Early warning systems for emergency situations
This equipment enables the processing plant to operate with minimal effort and maximum precision.
Construction material and packaging type
Wastewater treatment plants in hospitals typically consist of prefabricated metal structures (epoxy-coated carbon steel) or polyethylene
. For larger projects, reinforced concrete is often used. The choice of primary material depends on the required treatment capacity, installation requirements, and project budget.
A simplified guide to septic tanks
In conclusion
A hospital’s wastewater treatment plant is a complex system of mechanical, biological, and chemical equipment that work together to convert contaminated wastewater into drinking water that can either be disposed of or reused.
Key components of the plant include:
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Garbage truck
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Expansion tank
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pH regulation system
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Coagulation and sedimentation apparatus
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Bioreactor
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The system includes disinfection
, sludge removal and intelligent control equipment.
The use of a standard set and regular maintenance ensure stable operation of the equipment and its full compliance with the hospital’s environmental standards.