To Remove Doubt, Test It Out! See also issues relating to swimming pools
Disinfection is necessary to destroy pathogenic (disease-producing) bacteria and other harmful organisms that may be present in water. Methods of disinfection include chlorination, distillation, ultraviolet treatment, ozonation, and iodine or bromine feed.
Chlorination - for more detail see issues relating to swimming pools
Chlorine is effective against bacteria and requires short to moderate
contact time. It is readily available in several forms and it
and its effect is easily tested. High chlorine concentrations
have objectionable tastes and odors, and even low concentrations
react with some organic compounds to form strong, unpleasant tastes
and odors. Trihalomethanes, by-products produced when chlorine
reacts with humic and fulvic organic compounds present in natural
waters, have potential adverse health effects.
Inorganic materials such as dissolved iron and manganese are oxidized by chlorine and converted to insoluble forms. Chlorine reacts with organic matter usually breaking it down into simpler substances.
Ultraviolet light (UV) disinfection units are effective at destroying bacteria and viruses. UV disinfects water without adding chemicals. It does not create new chemical complexes, nor does it change the taste or odor of the water and it does not remove any minerals in the water.
Ozone generators are used in some systems to produce small quantities of ozone gas, which is a very strong oxidizing agent and is effective in killing bacteria with even brief exposure times. Ozone is also effective in oxidizing organic matter, iron, and manganese. The use of ozone does not form trihalomethanes, as can chlorine. It produces no tastes or odors in the water. Ozone is unstable and has a very short life, so it must be generated at the point of use. Ozone is hazardous to health when breathed.
for more detail see issues relating to swimming pools
Both iodination and bromination have been proven effective in
controlling most disease-producing bacteria, even with relatively
short contact time. These methods have been used successfully
for disinfection of swimming pools, but bromine is not recommended
for drinking water. Iodine disinfection is not recommended for
long-term or routine drinking water supply application. There
is some evidence that iodine intakes of as little as 0.5 milligrams
per day might have resulted in hyperthyroidism, thyroiditis, or
increased rates of thyroid carcinomas.
Prepared by Trevor Croll,
42 Pearse Street, Keperra, Queensland Australia, 4054.
Phone 61 7 3855 1115