Water, sanitation, hygiene and public health

Water, Sanitation, Hygiene, and Public Health

Importance of Water in the Human Body

  • Lungs: 90% water

  • Blood: 82% water

  • Skin: 80% water

  • Muscle: 75% water

  • Brain: 70% water

  • Bones: 22% water

Natural Water Supplies

  • Surface Water: Rivers and lakes.

  • Groundwater: Underground water.

  • Rainwater: Collected and utilized.

  • Pollution Considerations:

    • Shallow sources are easily contaminated.

    • Deep sources require purification.

Water Purification Technologies

  • Chlorination: Common method for disinfecting water.

  • New Technologies: Innovations are emerging to improve purification processes.

  • Purification Steps:

    • Large scale: Coagulation, sedimentation, filtration, disinfection.

    • Small scale: Boiling, filtration, disinfection.

Water Treatment Process

  1. Intake: Water is drawn from rivers or canals.

    • Must be protected from pollution (especially fecal).

  2. Sedimentation: Water allowed to settle in tanks.

    • Larger particles settle down.

  3. Coagulation: Coagulants like alum added to enhance sedimentation.

  4. Filtration: Mechanical sand filters remove smaller impurities.

    • Efficiency: Up to 95% for microorganisms.

  5. Disinfection: Chlorine added for safety to prevent contamination during distribution.

    • Residual chlorine ensures safety until water reaches consumers.

Simplified Water Treatment Flow Diagram

  • Source Water Supply: Includes rivers, lakes, and rainwater.

  • Treatment steps:

    • Chlorination: Addition of chlorine gas.

    • Filtration: Preliminary physical screening and removal of sediment.

    • Sedimentation and Reduction: Removal of impurities for clearer water.

Coagulation-Flocculation

  • Coagulant (like alum) is added to raw water.

  • Forms precipitates trapping impurities.

  • Stages:

    • Rapid mixing for coagulant mixing.

    • Slow mixing allows floc to form and settle.

Small-Scale Purification Techniques

  • Boiling: Effective for pathogen removal.

  • Filtration: Use of domestic filters that involve layers of clay or ceramic.

    • Chlorine may be added for further disinfection.

    • Regular maintenance is essential to avoid contamination.

Types of Water Sources

  1. River Water:

    • Collected directly for domestic use, but may be contaminated.

    • Cooling purposes without proper purification is risky.

  2. Shallow Wells:

    • Provides semi-sanitized water but can be polluted.

    • Requires proper maintenance and monitoring.

  3. Deep Wells:

    • Obtains cleaner water but can still face contamination risks.

    • May contain harmful chemicals leading to health issues like fluorosis.

Standards of Potable Water

  • Physical Standards: Must be clear, odorless, uncolored, and have an agreeable taste.

  • Chemical Standards: Include acceptable levels of hardness with normal pH levels.

    • Hard water can cause health and maintenance issues.

  • Bacteriological Standards: Focus on absence of pathogens like E. coli; coliform counts indicate pollution levels.

Water Pollution

  • Definition: Any changes in water that negatively affect living organisms or water usability.

  • Causes of Pollution:

    • Biological: Bacteria, viruses, parasites.

    • Chemical: Metals, pesticides, and other organic and inorganic chemicals.

    • Physical: Sediment affecting photosynthesis.

Waterborne Epidemics

  • Characteristics:

    • Common source affecting all demographics.

  • Symptoms: Diarrheal diseases prevalent during outbreaks.

  • Epidemiological Response:

    • Control sources, increase sanitation measures, and surveillance.

Control of Waterborne Epidemics

  1. Source Control: Identifying and managing the original water source.

  2. Increased Chemical Treatment: Adding chlorine to kill pathogens; careful monitoring of residual levels.

Conclusion

  • Water Quality Monitoring: Essential for public health, requiring continual vigilance and advanced purification methods.