PSM Made Easy

Disinfection of Wells during an Emergency – The Double Pot Method

Disinfection of Wells during an Emergency – The Double Pot Method
E.g. an outbreak of cholera

  • During an emergency, it is desirable to ensure a constant dosage of chlorine to well water
  • One method of doing this is the ‘Double pot method’
  • The method is an improvement devised by the National Environmental Engineering Research Institute (NEERI), Nagpur, India
  • There are two cylindrical pots
  • One pot is placed inside the other
  • Outer pot:
    • Inside height is 30 cm
    • Inside diameter is 25 cm
    • A hole (1 cm diameter) is made at 4 cm above the bottom
  • Inside pot:
    • Fits into the outer pot
    • Has a hole (1 cm diameter) near the upper end
  • A mixture of 1 Kg bleaching powder and 2 Kg sand is prepared and moistened with some water
  • The inner pot is filled with this mixture up to 3 cm below the hole
  • The inner pot is placed into the outer one
  • The mouth of the latter is closed with polyethylene foil
  • The double pot is lowered into the well by means of a rope attached to the well kerb
  • The pot should be immersed at least 1 m below the water level to prevent damage by the buckets used for drawing water
  • This device works satisfactorily for 2 – 3 weeks in small household wells containing 4500 L of water and a draw off rate of 360 to 450 L per day

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