1. Types
    1. Sludge blanket Precipitator
    2. Solids recirculation Clarifiers
  2. Sludge blanket Precipitator
  3. Solids recirculation Clarifiers
  4. Cold Softening, addition of lime
    1. Calcium hardness , removal as calcium carbonate ppte
    2. Magnesium hardness ppte as magnesium hydroxide
    3. Bicarbonate alkalinity , first converted to carbonate then ppte as calcium carbonate
    4. Free carbon dioxide , converted to bicarbonate, then carbonate then ppte as calcium carbonate
    5. Silica converted to insoluble silica magnesium complex when it reacts with magnesium hydroxide
    6. Turbidity , from suspended solids
  5. Calcium hardness , removal as calcium carbonate ppte
  6. Magnesium hardness ppte as magnesium hydroxide
  7. Bicarbonate alkalinity , first converted to carbonate then ppte as calcium carbonate
  8. Free carbon dioxide , converted to bicarbonate, then carbonate then ppte as calcium carbonate
  9. Silica converted to insoluble silica magnesium complex when it reacts with magnesium hydroxide
  10. Turbidity , from suspended solids