Sanitary Engineering Lecture Notes

Introduction to Sanitary Engineering

• Importance for sanitary, civil, and environmental engineers
• Key subtopics:
  • Removal and disposal of human waste
  • Sewage treatment and disposal
  • Portable water treatment
  • Solid waste treatment

Definition of Sanitary Engineering

• Application of engineering methods to improve sanitation in human communities
• Focus on removal and disposal of human waste and supply of safe potable water
• Related fields include public health engineering and wastewater engineering

Aspects of Sanitary Engineering

1. Collection of human waste
2. Conveyance of waste
3. Disposal of waste

Interdisciplinary Nature

• Involves various fields:
  • Plumbing, fire protection, hydrology, microbiology, etc.

Importance of Sanitary Engineering

• Design of sewers, sewage treatment, wastewater treatment facilities
• Addressing water pollution and soil contamination

Terms Related to Sanitary Engineering

• Sewage: Wastewater from communities, major pollution source
• Types of sewage:
  • Domestic sewage
  • Industrial sewage
  • Stormwater
• Sewage effluent: Outflow from sewage treatment facilities
• Sludge: Waste from personal washing and cleaning
• Garbage: Unwanted materials
• Wastewater: Water negatively affected by human influence
• Greywater: Non-industrial wastewater from domestic use
• Infiltration: Downward movement of water through soil
• Exfiltration: Upward movement of water through soil

Wastewater Treatment

• Process of removing contaminants from wastewater (physical, chemical, biological processes)
• Anaerobic digestion: Breakdown of organic matter without oxygen, producing methane
• Biodegradable: Capable of decomposition

Role of Sanitary Engineers

• Water supply management
• Wastewater management
• Stormwater management
• Solid waste management

Sewage System Types

1. Separate sewage systems
   • Advantages: Reduced load on treatment plants, smaller sewer sizes
   • Disadvantages: Difficult cleaning, high maintenance costs
2. Combined sewer systems
   • Advantages: Easier cleaning, reasonable maintenance costs
   • Disadvantages: Overflow risks during storms, higher loads on treatment plants
3. Partially separate sewer systems
   • Combines features of both systems
   • Useful for managing stormwater and sewage effectively

Human Waste and Disposal Methods

• Definition: Byproduct of digestion (feces and urine)
• Open defecation as a challenge in developing countries
• Various methods of waste disposal:
  • Toilets (e.g., flush toilets, dry toilets)
  • Sanitary latrines, septic tanks, etc.

Health Risks

• Contaminated sewage can cause viral and bacterial diseases
• WHO report: 2.2 million deaths annually from contaminated water

Global Statistics on Sanitation

• 775,000 deaths annually due to unsafe sanitation
• 2.4 billion people lack access to adequate sanitation
• 15% of the world practices open defecation

Sanitation Facility Types

• Improved sanitation: Private facilities separating excreta from human contact
• Basic services: Shared facilities
• No services: Open defecation

Methods of Excreta Disposal

• Service type latrines: Conservancy systems, manual removal
• Non-service type latrines: Pit latrines, septic tanks
• Improved sanitation facilities: Water-carrying systems, sewage treatment

Specific Latrine Types

• Open field defecation: Not acceptable but sometimes inevitable
• Conservancy systems: Manual removal of waste
• Shallow trench latrines: Quick to implement but limited privacy
• Water seal latrines: More hygienic, uses water for flushing
• Septic tanks: For households without central sewer systems
• Biogas plants: Converts waste to energy

New Concepts

• Green toilets: Environmental-friendly systems
• Biotoilet system: Converts waste to liquid and gases
• Zero discharge system: Separates solid and liquid waste for recycling

Conclusion

• Effective disposal of excreta is a social and health necessity
• Various disposal methods suitable for different communities and settings
• Importance of continuous improvement in sanitation facilities for public health

Final Remarks

• Aim for safe sewage disposal and treatment to protect public health
• Encouragement to like and subscribe for future lectures