Almost everyone knows that the water we use in the process of life is characterized by the so-called "hardness". This concept means the degree of its saturation with magnesium and calcium cations. Softening water can significantly improve its quality.
In “hard” water, products are boiled for a long time, some detergents, powder and soap practically do not “soap”, and a characteristic plaque (scale), consisting of mineral deposits, forms on water pipes and in kettles. In addition, such water can cause s alt deposits in the human body or in pets.
Water softening is carried out to remove the hardness s alts present in it. Any tap water, in addition to being purified from impurities and bacteria, undergoes a procedure for removing magnesium and calcium s alts. Water softening can be carried out in various ways. The choice of one or the other of them is determined mainly by the type and magnitude of water hardness, as well as in accordance with technical and economic feasibility.
It can be thermal (based on water heating), reagent (based on the binding of magnesium and calcium ions by certain reagents, followed by filtration of insoluble compounds) or a combined method (combines several methods of water treatment). The method of ion exchange is also very widespread, in which water is filtered through certain special materials. With this method of processing, the exchange of hydrogen and sodium ions, which are part of these filters, for magnesium and calcium ions. Various materials are used to filter water. Some of them are of natural origin, but different synthetic resins are most often used. Among the ultra-modern methods of water softening, nanofiltration should be highlighted.
Softened water supplied by centralized water supply systems should not have a hardness of more than 7 mg-eq / cubic dm. Only by agreement with the Sanitary and Epidemiological Service is it allowed to supply water with a hardness of up to 10 mg-eq / cubic dm.
Water softening in a cottage can be done using the reagent method, in which soda and lime are used as reagents. Liming is carried out when it is necessary to reduce the alkalinity and hardness of water. Soda with lime softens water in which magnesium and calcium are contained together with anions of strong acids. But do not forget that such processing has its adverse consequences. Softening water at home using the soda-lime method leads to saturationliquid with calcium carbonate and increase its pH.
Among the simplest methods, it should be noted boiling water for an hour, then settling it to precipitate, softening with various alkalis (potash, baking soda, ammonia), softening with almond bran obtained by grinding sweet almond seeds. Water intended for domestic use can be softened with ordinary brine or laundry soap. For professional water treatment at home, special softeners are used that resemble a balloon or urn in their appearance, which can be easily placed in the kitchen.
