Water is the foundation of life on our planet. This substance is very common on Earth and truly unique. Life originated from water, in all organisms it is the environment in which the chemical reactions necessary for existence occur. Also, this substance itself becomes a participant in some biological processes.
There is no absolutely pure water in nature. It contains various impurities that enter it from the environment. In rivers and reservoirs, the amount of dissolved substances is up to 0.1%, and in the seas and oceans - 3.5%.
In order for this vital substance to become usable, there are various methods of water purification. The main one is filtering through layers of a porous substance, which can be coal, calcined clay, gravel or sand, which allows you to get rid of suspended particles and the bulk of bacteria.
In order for water from rivers or lakes to fall into the water supply network, it is brought to the required quality. This process takes place at sewage treatment plants. Removal of suspended particles, allowing to lighten and discolour a substance, is called coagulation. Under the influence of special reagents, which can serve as substances of mineral origin, as well as polymers, adhesion of solid impurities in the form of flakes occurs. Then the water settles, and then it is additionally filtered. The disinfection process is carried out by adding chlorine in the form of lime. It may also be in a liquid state. In addition, the use of ozone is possible.
Modern methods of water purification allow disinfection from underground sources using ultraviolet rays. Fluorine, the presence of which exceeds the standards, is displayed by filters containing activated alumina.
Water purification methods can get rid of radioactive particles. To do this, deactivate. To remove impurities that add unnecessary color and smell, deodorization is carried out. This process is carried out by oxidation with ozone, potassium permanganate or chlorine dioxide. Activated carbon sorption is also possible .
Modern industry produces various devices that allow using tap water to obtain a better product. These include filters with one cleaning step. They are produced in the form of nozzles for a water tap or jugs. Their purpose is to clear chlorine and various mechanical impurities. Drinking water treatment methods that use such devices are based on the suspension of suspended particles in the filter element. However, the resource of the exchangeable substance is extremely small. It averages 400 liters.
Water purification methods with two- and three-stage filters allow you to get rid of iron, pesticides, chlorine, mechanical impurities, as well as hard salts. The cartridges contained in such devices produce several cycles of bringing tap water to the required quality. At the first stage, mechanical cleaning is performed, at the second - cleaning with activated carbon. When using three-stage filters, ion-exchange resin or activated carbon, which is enriched with various additives, is additionally used.
The best quality cleaning in the domestic environment can be achieved using the reverse osmosis method . It allows you to save water from nitrites and arsenic, asbestos and fluorine, iron and chlorine, all viruses and bacteria, magnesium and mercury, as well as nitrates. Such filters consist of mineralizers, ultraviolet lamps. These devices have high performance, in addition, they are compact, which is quite important when used at home.
Water purification methods using membrane filters allow you to remove the smallest suspended particles, as well as manganese, arsenic, mercury, iron, salts of heavy metals. They also rid bacteria and viruses of such devices.