Chlorine is a supplement and not a substitute to sand filtration
-It kills pathogenic bacteria
-But has no effect on spores and certain viruses (e.g. polio, viral hepatitis) except in high doses
In addition to being germicidal, it has other properties
-Oxidizes iron, manganese and hydrogen sulphide
-It destroys some taste and odour producing constituents
-It controls algae and slime organisms and aids coagulation
How does chlorine act as disinfectant?
When chlorine is added to water, it forms:
-Hydrochloric acid (HCl) and
-Hypochlorous acid (HOCl)
-HCL neutralizes the alkalinity of the water.
-The Hypochlorous acid ionizes to form hydrogen ions and hypochlorite ions (H^+, 〖OCl〗^-)
The disinfecting action is due to:
-hypochlorous acid and
-to some extent, due to hypochlorite ions
Chlorine disinfects best when the pH of water is around 7
-When the pH value exceeds 8.5, it is unreliable as a disinfectant (as 90% of the hypochlorous acid gets ionized to hypochlorite ions)
Fortunately, most waters have a pH value of 6 – 7.5
Membrane processes in water purification: http://www.ihatepsm.com/blog/membrane-processes-treatment-drinking-water
Super Chlorination and Break Point Chlorination: http://www.ihatepsm.com/blog/super-chlorination-and-break-point-chlorina...
Slow sand filter: http://www.ihatepsm.com/blog/slow-sand-filter-biological-filter
Rapid sand filter: http://www.ihatepsm.com/blog/rapid-sand-filter-mechanical-filter
Purification of water at a large scale: http://www.ihatepsm.com/blog/water-purification-large-scale-water-supply
Criteria for a Chemical to be Suitable as Water Disinfectant in Water Supplies: http://www.ihatepsm.com/blog/criteria-chemical-be-suitable-water-disinfe...
Water Supplies Disinfection with Chlorination: http://www.ihatepsm.com/blog/water-supplies-disinfection-chlorination
Principles of Chlorination: http://www.ihatepsm.com/blog/principles-chlorination
Methods of Chlorination in Water Supplies: http://www.ihatepsm.com/blog/methods-chlorination-water-supplies
Horrock's Apparatus: http://www.ihatepsm.com/blog/horrock%E2%80%99s-apparatus
Disinfection of well during emergency: http://www.ihatepsm.com/blog/disinfection-wells-during-emergency-%E2%80%...
Double Pot method: http://www.ihatepsm.com/blog/disinfection-wells-during-emergency-%E2%80%...
Disinfection of Wells: http://www.ihatepsm.com/blog/disinfection-wells
OT and OTA test: http://www.ihatepsm.com/blog/ot-and-ota-test
Domestic or Household Purification of Water: http://www.ihatepsm.com/blog/domestic-or-household-purification-water