Is a water purifier a necessity in life, or is it just useless?

Water purifier or bottled water?

Image from hippopx

I believe that many families will be hesitant about these two ways of drinking water when purchasing drinking water equipment, especially the newly emerged water purifiers in recent years.

Some people say that water purifiers are a necessity in life, while others say that they are useless... So is a water purifier worth buying? To what extent can it purify water?

Tap water cannot be drunk directly

We have been taught since childhood that you cannot drink raw water, as it will make you sick.

As for the reasons, there are mainly the following points: First, the natural water pumped from rivers is not necessarily clean; second, although natural water undergoes filtration, sedimentation, and disinfection in the water plant, the disinfection is not necessarily thorough, and there may still be a certain amount of bacteria, and there will also be residual chlorine (hypochlorite and organochlorine).

Secondly, after natural water leaves the factory, it flows through metal water pipes, water towers, water tanks and other water supply facilities, and inevitably comes into contact with pollutants (including bacteria and viruses, etc.). According to the test results of the Chinese Academy of Preventive Medicine, the drinking water compliance rate of 35 major cities in my country is only 23%.

Image from hippopx

Is it okay to drink it after boiling it at high temperature?

That may not be the case.

Although high-temperature boiling can decompose and volatilize unstable residual chlorine, the chloride ions are still there, and the "corpses" of viruses and bacteria cannot disappear. Therefore, tap water is still a long way from direct drinking water.

So what kind of water can be called drinking water?

Direct drinking water must meet or exceed the healthy water standards published by the World Health Organization (WHO): first, there must be no harmful substances in the water, let alone any peculiar smell; second, it must contain an appropriate amount of minerals that are beneficial to the human body; third, it must be weakly alkaline.

In view of this, the state has formulated strict standards for direct drinking water. The "Sanitary Standards for Direct Drinking Water from Drinking Water Pipes by Quality (Draft for Discussion)" stipulates that the water from the tap must meet the requirements of the "Drinking Purified Water Quality Standard (CJ 94)" at all times.

So how do you turn tap water into drinking water? It's simple: just add a water purifier to the water terminal at home or office.

Water purifiers have the same goal in different ways

The basic principle of a water purifier is to use purification devices such as PP cotton, activated carbon, and reverse osmosis membrane to purify tap water layer by layer to remove impurities.

There are three main types of impurities here: one is viruses, bacteria and their "corpses"; the second is suspended matter, rust, residual chlorine, etc.; the third is heavy metal substances (such as mercury, copper, inorganic arsenic, zinc, etc.).

From the structural point of view, the first half of the water purifier is roughly the same, mainly PP cotton, activated carbon and coarse filter elements, etc. The second half is the key to the water purification equipment, mainly ultrafiltration membrane, reverse osmosis membrane, etc. Different water purifiers appear on the market according to the difference in the second half, and UF and RO are currently the most commonly used.

UF is an ultrafiltration water purifier, and its core component is an ultrafiltration membrane with a filtration accuracy of about 0.1 microns, which can effectively remove bacteria or virus corpses, suspended matter, rust, microorganisms, residual chlorine, etc. in tap water. UF is a typical physical filtration, which can work under normal water pressure and does not require electricity. Its disadvantage is that it cannot filter out heavy metal substances.

Image from hippopx

RO is a reverse osmosis water purifier. Its core component is a reverse osmosis membrane with a very small pore size. The filtration accuracy can reach 0.0001 microns. Only water molecules can pass through, and heavy metal substances such as mercury, lead, and copper that are harmful to the human body can also be filtered out. Obviously, RO has a better filtration effect than UF.

RO has a strong ability to process tap water, but the conditions it requires are relatively high. First, it needs water pressure to work. At present, the water pressure in people's homes is generally not high, so it must be connected to the power supply. Fortunately, RO only uses electricity when purifying water, and the power is very low, similar to the LED type in ordinary bedrooms, so it will not bring electricity bill pressure.

Second, due to the small pore size of the RO reverse osmosis membrane, a lot of wastewater is generated during operation. Moreover, as the use time increases, substances such as silicon and calcium carbonate will remain on the surface of the RO membrane, preventing more and more water from passing through, thereby generating more wastewater.

Therefore, the filter element of the RO water purifier needs to be replaced after a period of use. Fortunately, for most families, the wastewater generated by RO has its own uses: because its purity is between tap water and UF purified water, and it flows out through an independent pipe, it can be completely used for washing clothes, mopping the floor, etc.

Solve doubts and choose what you need

Now we know that water purifiers can turn tap water into drinking water, thus ensuring human health. So what issues should be considered when choosing a water purifier?

First, what is the quality of the water used in your home or office.

From the production process of tap water, we can know that water quality is affected by water source and water pipes. Water source pollution in my country is serious and fresh water resources are limited. From water tower to user, tap water pipes are buried in the wall all year round, and minerals and microorganisms in the water are precipitated to form scale and breed bacteria.

Before purchasing a water purifier, you should first understand the water source and water pipeline of the tap water in your area, so as to provide a reference for the subsequent regular replacement of the water purifier filter.

Image from hippopx

Second, what type should I choose? UF or RO?

After understanding the tap water quality in your area, you can choose a water purifier accordingly.

It is recommended to narrow down the choices and choose two types of water purifiers that are recognized by the market for good water purification effect, high technology and high cost performance, UF and RO. If the requirements for filtering heavy metals are not high, choose UF, otherwise it is recommended to choose RO.

Third, what should I do if the water filtered by RO water purifier lacks trace elements?

In fact, the trace elements provided by water to the human body are very limited. Take calcium as an example. The calcium contained in a cup of milk is equivalent to that in 200 bottles of mineral water. The little calcium lost by drinking water directly has little effect on health.

If you really want to solve this problem, you can add a weak alkaline filter element at the back end of the RO membrane and add various trace elements on your own.

END

Tadpole Musical Notation original article, please indicate the source when reprinting

Editor/Xiao Xitushuo