Posted by Chlorination is used to disinfect the drinking water. There are different types of chlorination.
Table of Contents
Pre Chlorination
This is practiced by adding chlorine before filtration or rather sedimentation. In pre chlorination the 5mg to 10mg of chlorine per liter is added to the water. After treatment of water the chlorine will be present as 0.5 to 1 mg as residual.
Post Chlorination
This is done after water treatment. In this type of chlorination also residual chlorine is available as 0.5 to 2 mg per liter.
Plain Chlorination
It simply means that no other treatment applied to the water except chlorination. Usually, chlorination done such that 0.5 mg to 1 mg per liter chlorine being available residue.
Double Chlorination
It simply indicates that both the pre chlorination and the post chlorination are applied to the water.
Super Chlorination
Super chlorination means adding excess amount of chlorine say 5mg to 15mg per liter is applied. This is done during pandemics.
Break Point chlorination
The concept behind break point chlorination is that some part of the chlorine is consumed in killing the bacteria. The additional amount of chlorine will remain as residual.
Dechlorination
It simply means removing chlorine from the water. This could be done by aerating the water. Dechlorination can also be done by dechlorinating agents.
Some dechlorinating agents are
- Sulphur Dioxide Gas (SO2)
- Activated Carbon
- Sodium thiosulphate (Na2S2O3)
- Sodium Metabisulphate (Na2S2O5)
- Sodium sulphite (Na2SO3)
- Sodium bisulphite (NaHSO3)
- Ammonia as (NH4OH)
Desirable Properties Of Potable Water
- Potable water should be colorless and odorless.
- Drinking water should be free from harmful microorganisms.
- It should have some minerals and salts for body requirements and some gases to add taste.
- It is desirable that drinking water is free from suspended particles.
FAQs
How to test the residual chlorine?
There are four ways to determine residual chlorine. Orthotolidine test, D.P.D. Test, Chlorotex test, Starch Iodine Test.
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