An ancient proverb says: we are what we eat and drink. This is life. There is no arguing, since our body is almost seventy-five percent water. Without water, a person can live no more than a week, and in the desert die from dehydration in two hours. The quality of drinking natural affects the state of the human body. And how we live depends on a lot, but first of all on what kind of water we drink and on which we prepare our own food.
Quality of life issue
Comparisons of drinking water before and after treatment in water supply networks are not encouraging for many indicators, and sometimes even frightening. And in many respects it depends on its quality in reservoirs of a specific locality and external conditions. That is, an environmental analysis of the area is needed: how close are the large industrial cities to the source. And for underground sources, the answer to the question about water quality is provided by analysis and purification of water from the well. How to purify water, that is, which method of purification is most effective in a particular area, will be indicated by a biochemical analysis from the well prior to purification.
The reports of many international organizations that deal with water quality issues are horrifying. More than eighty countries of the world are experiencing problems associated with its shortage. And half of these countries are generally on the verge of a water crisis. There is an acute question of quantity, not to mention the quality of water. Water is a universal solvent. Therefore, outdated technologies for water treatment and subsequent treatment at industrial water treatment plants do not eliminate the problems of the presence of harmful and dangerous amounts of mineral (iron, manganese, copper, mercury, aluminum, etc.) and organic substances (ammonia, nitrates, nitrites, phosphates, etc.) in the water. ) Virological, bacteriological studies in many countries show that the standards are not respected everywhere in these parameters. Additional cleaning is necessary at home, because there is a threat of diseases caused by viruses, bacteria, protozoa and other microorganisms. The cheapest way of disinfection, chlorination, if it does not follow the rules, leads to the fact that in the water an amount of carcinogenic chlorine compounds incompatible with health is formed. Add here the environmental problems and the problems of deterioration of the water supply systems of old industrial cities, and it becomes clear how urgent the problem is. Water before treatment and water after treatment are not always so different in quality.
Industrial scale cleaning
Natural water from the river (cities were always built near natural reservoirs) falls into the water intake. Here, its location is very important, the fence is held upstream of all residential buildings and enterprises of the city, in the so-called sanitary zone. After the intake, water enters the sumps, where the pre-treatment stage begins. Depending on the quality of the water before treatment and the water after treatment, appropriate reagents are used or not in the sump. For enlargement (coagulation) of suspended particles, salts of iron or aluminum are introduced into the water. The harmful impurities glued together are disposed of at the filter station using washable strainers made of water-neutral materials or stainless steel. Then finer filtering for drinking water is carried out using cartridge filters that trap particles from 5 microns. Water after filter cleaning subjected to stiffness control, iron content for additional purification.
A special cleaning step - disinfection
Drinking tap water in a large industrial city, although it raises complaints, is still, for the most part, to taste. But non-compliance with sanitary standards is a matter of jurisdiction. There are emergency situations at a large state-owned enterprise, but they are obliged to immediately notify consumers about this. In addition, what water after cleaning reaches the consumer in an industrial way, it still largely depends on the quality of pipes in the systems of cities, our houses and apartments. Therefore, the final stage of disinfection occupies a special place in the purification cycle. The most common and cheapest way to disinfect is chlorination. But due to the increase in standards for chlorine-containing substances, this method does not improve the quality of the outlet water. Drinking water comparisons before and after treatment chlorination sometimes sharply raises the question of how to turn this disinfected water into drinking water.
Ozonization disinfection
After chlorine disinfection, organochlorine compounds are found in water that do not lose their toxicity even after settling tap water at home. There are problems with the lack of chlorine reagents. These problems are deprived of the method of disinfection at wastewater treatment plants using ozone treatment plants. In many cases, ozonation is used even at the stage of preparation for purification. This method is more efficient and safer. Ozone in sufficient quantities can be obtained directly at the place where it is used. Ozonation can be used in combination with other oxidizing agents, chlorine, as well as with ultrasonic treatment and ultraviolet radiation. A positive effect in the fight against bacteria gives an ozone concentration of 0.4 ml per liter for only four minutes. With ozonation, drinking water after purification has no extraneous taste impurities and extraneous odors. Drinking water is transparent without violating its natural properties. Excess ozone is converted to oxygen without affecting the taste of the water. The reason that the ozone disinfection method is used less frequently than chlorination is most likely due to the fact that the properties of aqueous solutions of ozone and how water before treatment and water after treatment affects the human body are not so thoroughly studied.
Alternative Disinfection Methods
What kind of disinfection method to choose is determined taking into account costs, productivity and, of course, the required volumes of drinking water. Probably the most ancient is the method of exposure to water molecules of noble metal ions (silver). It is clear that this method cannot be used on an industrial scale. Even rarer, due to the insecurity of the method, is disinfection by radiation. But ultraviolet treatment plants for drinking water are increasingly being used in domestic wastewater treatment plants.
Excess iron in water
In a number of places, when drinking water is extracted from underground or ground sources, the water after filtering for some time remains transparent, but then turns yellow. This is the first sign of an excess of iron in it. In addition, such water has a specific glandular aftertaste. Ignoring this problem is dangerous for human health and the quality of his life, because such water leads to damage to household appliances using such a liquid.
There are no universal methods for cleaning iron. For water extracted from ground-based sources, the reagent method is used using the same chlorine or ozone, less commonly, potassium permanganate or sodium hydrochloride. And for water produced from underground sources, methods using reagents and reagents, such as aeration, are suitable. Aeration is the intensive injection of air to saturate with oxygen. At home, a method of running water with excess iron through filters with special materials to remove oxidized and dissolved iron is used. The bad taste of the water after the water purification filter almost disappears.
Hard water
Resting somewhere, you hear: what water is soft - you can’t wash off the soap. But more often the problem of increased rigidity arises. It is enough to recall a teapot spoiled by scum and tasteless tea or coffee in such water, and it is clear that this affects the quality of human life. Excessive water soluble salts make water hard. This stiffness is temporary, eliminated by boiling. But salts of strong acids, sulfates and chlorides form a hardness that does not change when boiled. She is constant. In such cases, reagent purification methods or more expensive ones are used - freezing, distillation, electrodialysis. In domestic conditions, filters based on reverse osmosis are used to purify hard groundwater. Water before treatment and water after treatment reverse osmosis in the analysis gives impressive results.
Reverse osmosis
Reverse osmosis is a deep, up to ninety-five percent, treatment. The separation of all substances contained in water is carried out on the basis of the use of semipermeable membranes. The membranes are made of modern porous materials. There are polyamide, cellulose acetate, etc. The pores of such membranes are only one thousandth of a micron in size, through which only water molecules pass. All impurities, including microorganisms, settle on the membrane. If there is a question about how to purify tap water, this is the most high-quality, reliable, environmentally friendly way to improve the natural properties of water after its purification.
Charcoal filters. Mineral water enrichment
Filters that use the sorbing properties of activated carbon are used in the final stages of post-treatment when minor deviations in color, smell or taste must be eliminated. For the same purposes, natural minerals are used: mountain quartz, silicon, shungite. The water enriched with these minerals tastes like spring water.
New water treatment technologies
Recent research into the use of nanotechnology in the purification of drinking water yields impressive results. Studies of the properties of quartz microparticles coated with a nanometer layer of hydrocarbon substances have shown their ability to attract pathogens and biological molecules to themselves (electrostatic attraction). Simply, the nanoparticles are placed in contaminated water, and then the formed nanopowder is removed by filtration.
Many countries are currently working on the creation of nanofiltration devices. Cleaning plants by catalytic and electrochemical methods appear. Chemical methods of purification at the atomic level are constantly being improved.