Dialysis
Chloramine must be removed from the water prior to use in
kidney dialysis machines, as it would come in contact with the bloodstream across a permeable membrane. However, since chloramine is neutralized by the digestive process, kidney dialysis patients can still safely drink chloramine-treated water.
[14]
Ultraviolet light
The use of
ultraviolet (UV) light for chlorine or chloramine removal is an established technology that has been widely accepted in pharmaceutical, beverage, and dialysis applications.
[15] UV is also used for disinfection at aquatic facilities.
Superchlorination
Chloramine can be removed from tap water by treatment with superchlorination (10 ppm or more of free chlorine, such as from a dose of
sodium hypochlorite bleach or pool sanitizer) while maintaining a pH of about 7 (such as from a dose of hydrochloric acid). Hypochlorous acid from the free chlorine strips the ammonia from the chloramine, and the ammonia outgasses from the surface of the bulk water. This process takes about 24 hours for normal tap water concentrations of a few ppm of chloramine. Residual free chlorine can then be removed by exposure to bright sunlight for about 4 hours.[
citation needed]
Ascorbic Acid & Sodium Ascorbate
Ascorbic acid and
sodium ascorbate completely neutralize both
chlorine and chloramine, but degrade in a day or two, which makes them usable only for short-term applications. SFPUC determined that 1000 mg of Vitamin C tablets, crushed and mixed in with bath water, completely remove chloramine in a medium-size bathtub without significantly depressing pH.
[16]
Activated carbon
Activated carbon has been used for chloramine removal long before catalytic
carbon became available; standard activated carbon requires a very long contact time, which means a large volume of carbon is needed. For thorough removal, up to four times the contact time of catalytic carbon may be required.
Most
dialysis units now depend on
granular activated carbon (GAC) filters, two of which should be placed in series so that chloramine breakthrough can be detected after the first one, before the second one fails.
[17] Additionally,
sodium metabisulfite injection may be used in certain circumstances.
[18]
Campden tablets
Home brewers use reducing agents such as
sodium metabisulfite or
potassium metabisulfite (both proprietary sold as
Campden tablets) to remove chloramine from brewing
fermented beverages. However, residual sodium can cause off flavors in beer
[19] so
potassium metabisulfite is preferred.
Sodium thiosulfate
Sodium thiosulfate is used to dechlorinate tap water for aquariums or treat effluent from waste water treatments prior to release into rivers. The reduction reaction is analogous to the iodine reduction reaction. Treatment of tap water requires between 0.1 grams and 0.3 grams of pentahydrated (crystalline) sodium thiosulfate per 10 liters of water. Many animals are sensitive to chloramine, and it must be removed from water given to many animals in zoos.
Other methods
Chloramine, like
chlorine, can be removed by boiling and aging. However, time required to remove chloramine is much longer than that of chlorine. The time required to remove half of the chloramine (half-life) from 10 gallons of water by boiling is 26.6 hours, whereas the half-life of free chlorine in boiling 10 gallons of water is only 1.8 hours.
[20]
