Sludge and Waste Gas Treatment Technology of Hospital Sewage Treatment System

Learn about the complete sludge and waste gas treatment technology in hospital sewage treatment systems, including sludge classification, disinfection, dewatering, and hazardous disposal. Explore exhaust gas purification methods such as ozone, ultraviolet, and photocatalytic treatment to ensure safe and compliant hospital wastewater management.

In a hospital sewage treatment system, sludge y waste gas are critical byproducts that must be properly managed to prevent secondary pollution, odor emissions, and pathogen spread.
Hospital wastewater contains pathogenic microorganisms, toxic chemicals, and organic pollutants that make its byproducts particularly hazardous.

Therefore, effective sludge stabilization, disinfection, dewatering, and exhaust gas purification are essential for ensuring environmental safety y public health protection.

Hospital sludge is generated from multiple stages of the wastewater treatment process. It is typically categorized as:

• Septic tank sludge – from fecal matter and organic solids.
• Primary sedimentation sludge – from suspended solids in raw sewage.
• Secondary (biological) sludge – excess biomass from biological treatment.
• Chemical (coagulation) sludge – produced during chemical precipitation.
• Digested sludge – stabilized through biological digestion.

The volume and characteristics of sludge depend on inflow quality, treatment process type, and operation efficiency.

Note: For septic tanks handling radioactive sewage, sludge cleaning must occur every six months after confirming that radioactivity levels meet safety standards.

The treatment process for hospital sludge typically includes desinfección, dewatering, and final disposal.

The primary goal of sludge disinfection is to destroy pathogenic microorganisms and prevent secondary contamination during storage, transport, and disposal.

Sludge disinfection methods include chemical, thermal, and ultraviolet (UV) processes.

(1) Chemical Disinfection with Lime

• Agregar 15 g of lime per liter of sludge to raise pH to 11–12.
• Maintain full mixing and contact for 30–60 minutes, followed by storage for 7 days to ensure pathogen inactivation.

(2) Disinfection with Bleaching Powder

• Use 10–15% bleaching powder (calcium hypochlorite) relative to sludge volume.
• Provides strong bactericidal effects with low operational cost.

(3) Ultraviolet Irradiation

• Applicable in facilities with low sludge volume and advanced infrastructure.
• Provides clean, residue-free sterilization.

Design Capacity:

• The sludge disinfection or storage tank should have a capacity ≥ 24-hour sludge production, but not less than 1 m³.
• Agitation devices are required to ensure uniform chemical contact.

Discharge Strategy:

• If wet sludge output < 2 m³/day, it can be reintroduced into the septic tank after disinfection.
• If > 2 m³/day, it must be mechanically dewatered, sealed, and transported for incineration as hazardous waste.

The goal of sludge dewatering is to reduce water content y volume, facilitating handling and disposal while minimizing odor and leakage.

Recommended Equipment:

• Centrifugal dewatering machine for continuous operation.
• Pre-conditioning using organic polymers or inorganic coagulants to enhance separation efficiency.

Key Design Considerations:

• Enclose all dewatering areas to prevent odor release.
• Include ventilation and exhaust gas collection systems with corrosion-resistant ducts.
• Dehydrated sludge must be sealed and bagged before off-site transportation.

According to the China State Environmental Protection Administration, hospital sludge is categorized as hazardous waste due to its high microbial and chemical risk.

Disposal Requirements:

• Must be sent to licensed medical waste incineration facilities.
• Landfilling is strictly prohibited unless it meets sterility and stabilization standards.
• All sludge containers should be labeled “Infectious Waste – Sludge” for tracking and regulation compliance.

Waste gases from hospital sewage treatment tanks can contain volatile organic compounds (VOCs), odor-causing substances, and even airborne pathogens from the liquid surface.

To prevent virus aerosolization and atmospheric contamination, all water treatment tanks should be sealed with cover plates.

Process Flow:

1. Enclose treatment tanks with sealed covers (with inlet/outlet openings).
2. Collect the exhaust gas through ductwork y fans.
3. Pass the gas through purification units such as:
   • Ozone disinfection systems
   • Peracetic acid or chlorine mist absorbers
   • Ultraviolet (UV-C) irradiation chambers
   • High-voltage electrostatic or photocatalytic reactors
   • Activated carbon adsorption filters
4. Release the purified air through an exhaust stack ≥15 m high to ensure atmospheric dispersion.

• Ventilation design must follow local exhaust principles to ensure efficient air capture and treatment.
• Centrifugal fans are recommended, with corrosion-resistant coatings if oxidizing disinfectants are used.
• Exhaust air velocity y pressure head should be determined based on the resistance of the chosen purification device.

• Regularly inspect sealing covers and duct joints for leakage.
• Replace filter media and UV lamps as scheduled.
• Monitor residual ozone concentration o disinfectant levels to ensure safety.

In modern hospital sewage treatment systems, sludge y waste gas treatment are indispensable for environmental protection and infection control.

• Sludge treatment requires rigorous desinfección, dewatering, and incineration to prevent pathogen release.
• Waste gas management through sealing, collection, and advanced oxidation or UV disinfection effectively eliminates airborne contaminants.

By integrating these technologies, hospitals can ensure their wastewater treatment plants operate safely, efficiently, and in full compliance with environmental and health regulations.

Because it contains high levels of pathogens, heavy metals, and toxic compounds that pose serious infection and pollution risks.

Chemical disinfection using lime or bleaching powder is reliable and cost-effective; desinfección ultravioleta is cleaner but suited to small systems.

Typically every 6–12 months, and radioactive sewage tanks should be cleaned every 6 months after safety testing.

Common options include ozone disinfection, UV irradiation, activated carbon adsorption, and photocatalytic oxidation.

After disinfection and dewatering, sludge must be sealed, labeled, and incinerated at a licensed medical waste facility.

Xian CHIWATEC Water Treatment Technology es una empresa de alta tecnología especializada en varios dispositivos de procesamiento de agua. Aparte de estos productos individuales, que cubren una serie de tipos y series, también podemos ayudar con proyectos de ingeniería integrales relacionados. Gracias a nuestro arduo trabajo y dedicación desde nuestra fundación, ahora somos uno de los fabricantes de equipos de tratamiento de agua de más rápido desarrollo en el oeste de China.

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