How do families get safe drinking water?

At present, to solve the problem of healthy drinking water in families, it is best to use different kinds of water: that is, water that enters the human body such as cooking, soup making and drinking, and bottled mineral water; Tap water is used for daily life such as washing vegetables, washing clothes, washing face and bathing. Of course, in some areas and time periods with unstable tap water quality, it is not bad to use water purifier, but it is not suitable for long-term use.

Not all bottled water is mineral water. There are two kinds of bottled water now: one is natural mineral water; The other is pure water (or drinking water). Barrel purified water is actually purified by tap water, which is not much different from the water purified by water purifier. Good natural mineral water generally comes from inaccessible alpine glaciers, mostly groundwater, which is closely protected by rock formations and isolated from surface pollution. But also contains a variety of mineral essence and trace elements, which is very suitable for human body.

Most water purifiers in the market use filtration to purify water. There are many kinds of filter elements used, including activated carbon, ultrafiltration membrane, ceramic filter element and reverse osmosis membrane. There are many kinds of filter elements, but the basic principle is the same, that is, bacteria, microorganisms and some impurities are removed by filtration. Different filter elements have different filtration degrees, ranging from carbon filtration to ultrafiltration membrane, and the filtration grade is between 0.5 micron and 100 micron. The highest degree of filtration is the reverse osmosis membrane, which can reach 0.000 1 micron (that is, 0. 1 nanometer).

The size of bacteria is micron (the smallest known bacteria is about 0.2 micron), and micron filtration grade can filter out most bacteria. But viruses, some harmful inorganic substances and metal salts cannot be filtered. The volume of virus is nanometer, mostly between 10 nm and 300 nm, so the reverse osmosis membrane can basically filter out all bacteria and viruses. Molecular inorganic substances can also be filtered out. However, there are still very few ions and metal salts that cannot be filtered out. Although there are many ways of disinfection, such as adding chlorine, ultraviolet rays, ozone and so on. However, there are few disinfection methods for household drinking fountains, and generally ultraviolet disinfection is used. At present, many household water purifiers have been equipped with ultraviolet rays.

As for soft water, it is two concepts with clean water. Soft water is aimed at the hardness of water, and has nothing to do with the cleanliness of water itself. The hardness of national standard drinking water is measured by the content of calcium carbonate: up to 450 mg of calcium carbonate is allowed in each liter of water. When the content of calcium carbonate is less than 150mg/l, it can be called soft water. Who does not think that the calcium carbonate content in drinking water will affect human health at 500 mg per liter. Hard water is annoying mainly because it will scale and affect the use of some equipment (such as washing machines, steam engines, boilers, domestic floor heating pipes).

Let's take a look at how the ordinary commercial direct drinking water system is handled. Take a five-star hotel as an example: when tap water is introduced, a raw water tank will be set to store water. Then it will be treated through the following processes: dosing, that is, adding chemical agents to generate larger suspended solids with some smaller impurities in water for filtration; Sand filtration: large impurities are filtered by a filter with a sandy filter element; Carbon filtration, that is, activated carbon filtration, is used to filter small impurities; Fine filtration, the filtration degree is about equivalent to ultrafiltration membrane; The filtered water uses a variable frequency pump or water tank, and an ultraviolet sterilizer is installed at the water supply outlet; Finally, it is sent to each room through stainless steel pipes.

The most commonly used method, whether for home or business, is filtration. The commercial water purification system can be treated step by step from coarse filtration to fine filtration. Before the fine filtration of water, sand is used to filter out large particles of impurities. If the raw water contains these large particles of impurities, it will damage the filter element of the household water purifier or reduce the filtration efficiency. In fact, the raw water treated by household water purifiers should meet the national standards. In other words, its function is roughly equivalent to purifying water that meets the drinking water standard into water that meets the drinking water purification standard.

Source: Sina Technology, Shell Network and other media.