The use of clean water enhances human health and immunity, moreover, the body itself is restored, using its own reserves. From time immemorial, people have settled near rivers and lakes, using the sources that nature gave for life. The most ancient civilizations were already able to purify water for the needs of citizens, passing it through layers of clay and sand. In those days, people did not use coagulants (these are the substances with which the primary purification of life-giving moisture is performed today).
So different pure water
In the modern world, it is believed that ideally a person should use three types of water in their homes:
- a water pipe that has passed the standard multiple rough cleaning and filtration in special settlers;
- household, pre-softened to prevent scale formation in heating devices, used for washing and washing;
- drinking, used exclusively for ingestion and cooking.
Plain water is provided by the urban water supply system. For self-cleaning at home, various filters, structuring systems and some minerals (such as shungite) that are recognized as useful are used. In addition, there are coagulants that disinfect water for home use.
What happens to water before getting into pipes
Before settling and filtering, preliminary rough water purification is carried out, intended for supply to urban water networks. First, in special containers, water and coagulants are quickly mixed (these are special chemicals). When coagulating, the electrostatic repulsion of particles dissolved in water decreases, they stick together. This facilitates and speeds up cleaning during settling and filtration.
The process in one tank should last about one minute. With a shorter time interval, the required uniformity of mixing the substance with water is not provided. With a longer interaction, the resulting flocs (sediment, adhering foreign particles) may be destroyed. After passing through several tanks, where coagulants for water are mixed with it at a gradually decreasing rate, the liquid undergoes sedimentation.
What does the beautiful word "flocculation" mean?
Coagulants are chemicals. Not all substances harmful to humans can be removed by conventional filtration in a short time. Some of them are in a dissolved state. If impurities or hydrosols are present in water, then coagulants for water purification at the moment of interaction form an insoluble precipitate with them in the form of a suspension. The process of formation of finely dispersed particles sticking together, larger "heaps" is called flocculation. The size of these new particles can reach several millimeters.
Of course, it is possible to purify water from various impurities by conventional filtration, only this will last several years, but water is needed daily in huge quantities. To make the cleaning process fast enough, coagulants are added to the mixers. This reduces the time of release of water from unnecessary harmful substances by only 30-45 minutes. Thanks to this acceleration, residents of large and small cities are able to use water without interruption without leaving their homes.
What happens in wastewater treatment plants
In water, even transparent at first glance, usually contains a huge amount of impurities. Among them may be the following substances:
- gypsum and chalk;
- sand and clay rocks;
- silt and plankton;
- sparingly soluble metal hydroxides;
- bacteria
- dissolved chemicals;
- various suspensions.
Heavy and large particles with a large specific gravity sink rather quickly to the bottom of the sump, in 1-2 minutes. Accelerating the process of sedimentation (sedimentation) of small particles, which can last up to two years, coagulants are added to the water. These are ferric chloride, ferrous sulfate, ferrous sulfate, hydroxosulphates and aluminum hydroxides, mixtures of salts of iron and aluminum, clay opacifiers, various flocculants and suspension clarifiers.
For the purification and clarification of water in the system of vertical sedimentation tanks per liter is consumed from 50 to 100 ml of reagents. Enlarged and glued together under the influence of chemicals colloidal particles precipitate, which is easily separated by further sedimentation and filtration.