CHLORINATION OF WATER AND BOILING ARE ESSENTIAL REQUIREMENTS AS REQUIRED FOR THE STERILISATION OF WATER

WHY CHLORINATION:--Chlorine is a very active agent and reacts quickly with organic matter present in the water .It is very effective against the bacteria commonly associated with water borne diseases and control of algae and other plant life. Chlorine eliminates tastes and odours,improves coagulation,oxides iron and manganese and too removes colour. Chlorine contents as essentially required to kill all typhoid, cholera and gastroenteritis germs however flue ,colds and hepatitis germs are killed only by boiling of the water.Chlorine may be used in three forms ie in case of small supplies bleaching powder or chloride and in case of the small town / village may be used as liqued or sodium hypochlorite solutions containing ten to fifteen percent by weight of the chlorine.The liquid form can be readily mixed with the water.In case of the medium and large size of the water - works ,as chlorine gas by gaseous chlorinator . Chlorine is very easily used in the form of a solution It is also recommended to arrange for the pre- Chlorination.The dosages should be residual of 0.1to 0.5 ppm which should be made in all water treatment plants.Chlorine gas which is most commonly used is supplied in steel cylinders compressed into liquid form.For disinfection 0.1to 0.2 ppm is necessary for good underground water and 0.5 to 1.5 ppm for surface waters .A dosage of 1.00 ppm may destroy most of the germs 

However in the case of highly polluted waters it may goes to be designed up to 3.00 ppm giving a residual of 1.00 ppm in twenty minutes.After chlorination water must be allowed to stand for at least 20 minutes before the use ( between the point of treatment and the first draw off )