Water Treatment

Question 1

The methods used in the treatment of water for domestic purposes are:

Answer 1

● Boiling
● Filtering
● Chlorinating
● Softening

Question 2

Boiling

Answer 2

Boil water for 15 minutes (kills most micro-organisms)

Question 3

Filtering

Answer 3

Use a fine filter to remove larger particles and larger micro-organisms (bacteria and
smaller micro-organisms are not removed)

Question 4

Chlorination

Answer 4

Bleach or water purification tablets are added, stirred and left for 30 minutes. The chlorine kills the micro-organisms.

Question 5

STEPS FOR LARGE SCALE PURIFICATION

Answer 5

1. Impure water is passed through screens to remove large objects e.g. twigs, diapers, dead
   animals.
2. The water is stored in reservoirs and suspended matter (e.g. soil) is allowed to settle.
3. The water is passed through a sand and gravel filter (removes small suspended particles which were not removed by allowing it to settle).
4. Carbon may be added to remove foul smells from the water.
5. Chlorine is added to kill harmful micro-organisms such as bacteria.
6. The pH of the water is adjusted and then run off for homes and factories.

Question 6

3 MAIN STAGES OF LARGE SCALE WATER PURIFICATION

Answer 6

● Settlement
● Filtration
● Chlorination