Understanding Water Treatment

The Central Water Authority (CWA) maintains a multi-tiered filtration network across Mauritius, delivering approximately 1,000,000 m³ of treated water daily produced from water treatment plants, containerised pressure filters, boreholes and pumping stations. It operates a vital water treatment infrastructure across Mauritius to ensure safe, potable water for both drinking and irrigation purposes.

Filtration Technologies & Distribution

  • Rapid Gravity Sand Filtration: Deployed across all 7 main Water Treatment Plants (WTPs) to handle high-volume primary filtration.
    • Coagulation & Flocculation: Aluminium sulfate (alum) is introduced to aggregate suspended solids into larger flocs.
    • Sedimentation: Flocs settle to the bottom of clarification basins under gravitational force.
    • Sand Filtration: Removes remaining particulates through fine sand media beds.
    • Disinfection: Primary and final disinfection across all treatment plants is carried out using chlorine dosing to eliminate pathogens.
  • Slow Sand Filtration: Used specifically at the La Marie WTP and Pailles WTP where water passes through biological and physical filter layers to remove organic matter and impurities.
  • Containerised Pressure Filtration (CPF) Plants:
    • Scale: 60 Nos. operational units spread across the country.
    • Output: Contributes approximately 120,000 m³/day.

Core Water Treatment Facilities

  1. Bagatelle WTP – 45,000m3
  2. La Marie WTP – 130,000m3
  3. La Nicolière WTP – 100,000m3
  4. Mont Blanc WTP – 12,000m3
  5. Pailles WTP – 85,000m3
  6. Piton du Milieu WTP – 35,000m3
  7. Rivière du Poste WTP – 20,000m3

Quality Control & Emergency Protocols

  • Continuous Monitoring: On-site mini-laboratories perform hourly operational testing. The CWA Central Laboratory conducts daily nationwide sampling for pH, turbidity, and free chlorine levels.
  • Regulatory Oversight: Water quality compliance is independently enforced by the Ministry of Health according to World Health Organization (WHO) standards.
  • Contamination Contingency Plan: In the event of a quality anomaly, isolation protocols are immediately executed—sealing facility inlets and outlets—followed by targeted system flushing and safety re-testing.
  • Environmental Impact Mitigation: Heavy rainfall and high river turbidity temporarily trigger automated shutdowns at affected Containerized Pressure Filter stations to safeguard filtration media and water quality.
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