Drinking water is arguably a rare but essential commodity for human life. Having clean water means having water that can be drunk without putting our health at risk. Unfortunately, not all people have clean water and millions of them die each year for this reason. Although drinking water comes from nature, between its origin and its destination, there is an intermediate process by which the water becomes drinkable. This drinking water has characteristics that natural water does not. In AgroCorrn we are going to talk to you about what drinking water is and its characteristics .
Which is the potable water
Although three-quarters of the planet is made up of water, not all water is drinkable or can be drunk by humans. Drinking water can only be fresh water . Only 2.5% of all the water on Earth is fresh water. Fresh water is distributed as follows, almost 70% of fresh water is frozen at the poles, 30% is found as moisture in the soil or forming aquifers and only 1% flows through the hydrographic basins forming rivers. and streams. Now, only 0.025% is drinkable water , but what does it mean that the water is drinkable?
Drinking water is that which is suitable for human consumption and that does not pose any risk to your health, that is, it is free of microorganisms and toxic substances. Normally the water that we drink and that is in our homes does not come directly from nature, but has been previously treated.
Water is a renewable but limited resource , it is increasingly scarce and many populations in the world still lack access to sources of drinking water. Global organizations such as UNICEF and the World Health Organization (WHO) have focused a large part of their efforts on fighting for accessibility to drinking water sources due to its direct relationship with health.
According to what the WHO establishes, access to drinking water exists when the nearest source is less than 1 km away and also when it is possible to extract or obtain at least 20 liters of water per day for each member of the family .
Drinking water characteristics
For water to be considered as drinking water, it must meet a series of characteristics. These characteristics are normally established in legislation and countries must comply with it. In the case of Spain, the characteristics of drinking water are regulated by Royal Decree 140/2003, of February 7, which establishes the sanitary criteria for the quality of water for human consumption. Depending on what the WHO establishes , drinking water:
- It must be clean and safe: both its consumption and its use in the production of other foods cannot carry any risk of contracting infectious diseases or other diseases (cholera, typhus, salmonellosis or methemoglobinemia).
- It must be colorless: this implies that the water must be clear, although it can sometimes be a bit whitish due to the chlorine.
- It must be odorless: that is, it must not have an odor since it should not have anything that can generate it.
- It must be tasteless: as in the previous case, it should not have any flavor either.
- Free of suspended elements: the water should not have anything that can generate turbidity. In some cases it may be a little translucent, but it may be due to pressure from the pipes and should disappear after a short time.
- It should not have organic pollutants such as pesticides (DDT, for example), or other inorganic pollutants (heavy metals), nor any radioactive elements.
- It must have a certain proportion of gases and dissolved inorganic salts .
- It must not contain pathogenic microorganisms that endanger health. For this, exhaustive analyzes of the concentration of coliform bacteria and others of fecal origin are carried out. The legislation establishes that there cannot be bacteria such as Escherichia coli , Pseudomonas aeruginosa , Enterococcus faecalis , Clostridium perfringens and others that can cause serious gastrointestinal infections and other disorders. Nor can more than 100 colony forming units (CFUs) of total aerobic bacteria be found.
Water purification process
As mentioned above, the water has to go through a series of treatments, known as the purification process. This occurs in water purification plants or ETAP. Through this process, “raw” water, thus called natural water, is purified and purified. In addition, this process ensures that there is a public drinking water distribution network so that it is accessible to all households and consumers.
The water purification process focuses on several treatments:
- Capture of water from natural water sources such as rivers, lakes or reservoirs: it is usually carried out by a set of electric pumps that collect the water. During the transport of the water, it is filtered through a series of grates of different sizes that retain the solids.
- Coagulation / Flocculation – Many solids can be removed by forming flocs, clots, or clumps. This treatment is able to eliminate algae and plankton, as well as other substances and chemicals that are used in this phase and that can produce odor and taste.
- Sedimentation: consists of the elimination of flocs through the action of gravity.
- Filtration: the water passes through a filter or a porous medium (sand, charcoal) to reduce the possible turbidity of the water and cysts of parasitic organisms. Learn more about it in this other AgroCorrn article on What is sedimentation in drinking water .
- Disinfection: consists of the elimination of pathogenic microorganisms from the water. In this step, the water purification process is completed. For disinfection, chemical processes such as the addition of chlorine or ozone among others, or by physical processes such as ultraviolet light, can be carried out.
When it is not possible to find potable water and it is necessary to resort to drinking water from other sources , the most affordable method that works best is to boil the water before consumption . This method at least ensures the elimination of pathogenic microorganisms that may be in the water, such as bacteria and viruses.
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