Ensure that everyone has access to this vital resource

What does water purification consist of?

Potable water is scarce vital resource. It is estimated that only 0.4% of water on the planet is fit for human consumption. This is why it is essential to invest in water purification, to ensure that everyone has access to this vital resource.

Water purification is the process by which water is treated so that it can be consumed by human beings without there being a risk to health. Consumption can refer to drinking and in the preparation of food.

Purification consists mainly of eliminating substances that are toxic to people, such as chromium, lead and zinc, as well as algae, sand or bacteria and viruses which can be present in water. In essence, it aims to eliminate any potential risk to the health of people.


Water is purified in what is technically known as a DWTP or Drinking Water Treatment Plant. This commonly refers to facilities such as water purification plants.

The water purification process varies according to the natural features of the terrain. For example:

  • If the source of the water is on the surface (river water or a lake), the purification treatment should consist of a process of separation of certain components of the natural water, followed by the precipitation of impurities, filtration and disinfection with chlorine or ozone.
  • If the water source contains salts and/or heavy metals the processes for eliminating these types of impurities is more complicated and costly. In coastal areas or regions with scarce water resources, potable water can be obtained by desalination, which normally involves reverse osmosis or distillation.

The water purification process by stages

1. Water pre-treatment

The first step consists of eliminating large solids. A grill is inserted to filter out fish and branches. Then, with the help of a desander, sand is separated from the water to avoid damaging pumps in the drinking water plant. In this stage, a pre-disinfection is also usually carried out to destroy various organic substances.

2. Coagulation-flocculation

Low-pressure pumps transport the water to a mixing chamber where the elements that purify the water are incorporated. In this stage of the purification process, the pH is adjusted by adding acids or alkalis and coagulating water agents.

3. Decantation

In the decanter, suspended particles in the water are separated by gravity. The denser harmful sediments remain at the bottom, where they are eliminated, and the least dense continue dissolved in the decanted water.

4. Filtration

After the decantation process, the water is passed through a porous medium to eliminate the least dense sediment. These filters strain out impurities. There are different kinds of filters, such as sand or activated carbon, and these can be open and work by gravity, or closed and work through pressure.

5. Disinfection of the water

Finally, chlorine is added to eliminate any kind of bacteria or virus. If it is necessary to eliminate pathogens from underground water or natural springs, this can be done through ultraviolet radiation or by applying ozone, for example.

6. Analysis

Once the DWTP process has completed, it is indispensable that various analyses of the water are performed in order to ensure that the purification process has been successful. Potable water must be colorless, odorless and insipid, and comply with the regulations in force in each country.



Making water a resource that humans can consume in a sustainable and safe way. An essential transformation for sustainable development that we guarantee through the design of drinking water treatment infrastructures and exploring new solutions to the challenges for water supply.