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5 Principles of Chlorination

For adequate chlorination, following rules should be followed:
1. The water to be chlorinated should be clear and free from turbidity.****

  • Turbidity impedes efficient chlorination

2. The chlorine demand of the water should be estimated first****

  • The chlorine demand of water is the difference between
  • the amount of chlorine added to the water and the amount of residual chlorine remaining in a sample of water
  • at the end of a specific period of contact (usually 60 min),
  • at a given temperature and pH of the water
    • In other words, it is the amount of chorine that is needed to destroy bacteria and to oxidize all the organic matter and ammonical substances present in the water
    • The point at which the chlorine demand of the water is met is called the ‘break point’
    • If further chlorine is added beyond the break point, ‘free chlorine begins to appear in the water

3. The contact period;

  • presence of free residual chlorine
    • for a contact period of at least one hour
    • is essential to kill bacteria and viruses
  • Chlorine has no effect on spores, protozoal cysts and helminthic ova, except in higher doses

4. The minimum recommended concentration of free chlorine is 0.5 mg/L for one hour

  • The free residual chlorine provides a margin of safety against subsequent microbial contamination such as may occur during storage and distribution

5. The sum of the ‘chlorine demand’ of the specific water plus the ‘free residual chlorine’ of 0.5 mg/L constitutes the correctdose of chlorine to be applied

OT and OTA test: Orthotolidine (OT) test and Orthotolidine – Arsenite (OTA) test

Membrane processes in water purification: Membrane Processes in Treatment of Drinking Water

Super Chlorination and Break Point Chlorination: Super Chlorination and Break Point Chlorination (Disinfecting Polluted Water)

Slow sand filter: Slow Sand Filter (Biological Filter)

Rapid sand filter: RAPID Sand Filter (Mechanical Filter)

Purification of water at a large scale: Water Purification at a LARGE SCALE (for water supply)

Criteria for a Chemical to be Suitable as Water Disinfectant in Water Supplies: Criteria for a Chemical to be Suitable as Water Disinfectant in Water Supplies

Water Supplies Disinfection with Chlorination: Water Supplies Disinfection with Chlorination

Principles of Chlorination: 5 Principles of Chlorination

Methods of Chlorination in Water Supplies: Methods of Chlorination in Water Supplies

Horrock's Apparatus: Horrock’s Apparatus

Disinfection of well during emergency: Disinfection of Wells during an Emergency – The Double Pot Method

Double Pot method: Disinfection of Wells during an Emergency – The Double Pot Method

Disinfection of Wells: Disinfection of Wells

OT and OTA test: OT and OTA test

Domestic or Household Purification of Water: Domestic or Household Purification of Water