DRINKING WATER GUIDELINES (WHO 2006)
Access to safe drinking water is essential for health and is a basic human right. Water is essential to sustain life and a satisfactory (adequate, safe and accessible) supply should be available to all. Diseases related to contamination of drinking water constitute a major burden on health. Safe drinking water is defined as that water that does not represent any significant risk to health over a lifetime of consumption. Those at greatest risk of waterborne disease are infants and young children, people who are debilitated or living under unsanitary conditions and the elderly.
Drinking water contamination can occur from
Ways to treat water
The simplest ways of removing microbes from water are boiling, disinfection and filtration.
Boiling water:- Bringing water to a rolling boil (prolonged and vigorous boiling is not required) is the most effective way to kill disease causing pathogens. The hot water should be allowed to cool down on its own without the addition of ice. If water for boiling is to be clarified, this should be done before boiling.
Disinfection:- Chemical disinfection is effective for killing bacteria, some viruses and some protozoa (does not kill cryptosporidium oocysts). Chlorine or Iodine are mostly used for disinfection. After disinfection, a carbon (charcoal) filter may be used to remove excess chlorine or iodine. If water is turbid, it should be clarified before disinfection. Clarification includes filtration, settling and decanting.
Filtration:- Various types of filters are available such as portable filters, ceramic filters and some carbon block filters. The filter's pore size rating must be 1 Ám (absolute) or less to ensure removal of cryptosporidium oocysts. Most filters do not remove viruses.
Desalinated water:- Increasing brackish or salty water which is otherwise unacceptable for human consumption is being desalinated to provide drinking water. Water sources used are estuarine water, coastal water, sea water, brackish inland water. These waters may contain hazards not encountered in fresh water systems. These include diverse harmful algae, certain free living bacteria (esp. Vibrio species), Chemicals such as boron and bromide. These can be removed by distillation and reverse, osmosis. Desalinated water is hard and bland, flavorless and thus is commonly treated by adding chemical constituents such as calcium and magnesium carbonate with carbon dioxide. Desalinated waters are commonly blended with small volumes of more mineral rich waters to improve their acceptability.
Advice for travelers
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