Ten questions and answers about daily drinking water quality!

- Nov 27, 2019-

Ten questions and answers about daily drinking water quality!

1. After the tap water is boiled, sometimes there is a layer of white floating matter or white scale on the surface, will it affect human health?

A: The white float or scale is the hydrogen carbonate (commonly known as temporary hardness) in water that is heated to become magnesium carbonate suspension or calcium carbonate precipitation.

total hardness

2. Sometimes the tap water looks like milky milk after flowing out of the faucet, but after a while, it turns back to clear. Why?

Answer: This is because the water needs to be pressurized in the pipeline that transports the tap water to the user. During the pressurization process, air will be mixed in, so that the tap water flowing from the faucet will entrain a large amount of air bubbles, and it will look cloudy. Can change back to clear, this has nothing to do with water quality.

3. Sometimes drinking tap water will have the smell of disinfectant water, why?

A: In order to ensure that tap water is safe and hygienic, and to avoid the occurrence of aquatic infectious diseases, the water supply is disinfected (chlorinated), and it must meet the residual chlorine range specified by the national drinking water sanitary standard. Therefore, some people will feel it when drinking. Disinfecting the taste of water, but this has no effect on human health, and people in advanced countries who have been accustomed to running aquatic drinks when traveling to other places, if the local tap water does not have such disinfecting taste, they dare not drink it with peace of mind.

4. Why is there a lot of deposits on the bottom of the water tank or water filter in the user's home?

A: Tap water will inevitably contain a small amount of particles that are invisible to the naked eye (even tap water in advanced countries). Although these particles are not harmful to the human body, they will precipitate and accumulate on the bottom of the reservoir or the filter of the water filter. It will be discovered by users for a period of time. In fact, even tap water in advanced countries cannot avoid this phenomenon. When this happens, users should ask the users to clean the reservoir or replace the water filter element.


5. When the aquarium in my home is sometimes replaced by tap water, the fish I keep cannot adapt. Why?

A: This is because the tap water often contains residual chlorine. Some fish are very sensitive to residual chlorine. Users can use activated carbon filtration or add an appropriate amount of sodium thiosulfate (commonly known as hypothermia) to remove residual chlorine. All methods are commercially available, users can contact the aquarium to purchase.

6. How does a commercially available water purifier purify water?

Answer: The commercially available water purifiers are generally divided into the following types: general filtration, activated carbon filtration, reverse osmosis, ion exchange resin, etc .; general filtration is to remove unclean solids in water using filter materials such as gravel or sponge; activity The main purpose of carbon filtration is to remove dissolved organics and residual chlorine in water; reverse osmosis can remove various impurities and produce water with lower conductivity; ion exchange resin can remove hardness (calcium and magnesium, etc.); when using these water purifiers It is necessary to pay attention to the problem of microorganisms, because these water purifiers are often hotbeds for microbial growth, so the water from the water purifier often contains a high number of bacteria, so it is necessary to periodically clean, replace or regenerate the filter, otherwise the water quality will be even worse. health.

residual chlorine

7. Water purifier sellers often use tap water as an electrolysis test to mislead the public into thinking that the quality of tap water is poor. What is the principle?

Answer: Some water purifier salesmen often take a simple electrolyzer and put it in tap water. After being energized, the tap water starts to produce a yellow-brown solid. When the amount of this solid increases, the tap water becomes reddish brown and turbid. Then use this phenomenon to criticize the poor quality of tap water in order to promote its water purifiers. In fact, this is to make use of the general public's lack of understanding of the phenomenon of electrolysis to achieve its marketing purpose, because tap water often contains some electrolytes (sodium, calcium, magnesium Plasma) has conductivity, and the electrolyzer used by the water purifier salesman often uses iron rods as anodes and aluminum rods as cathodes when it is put into tap water. After being energized, the iron rod of the anode will release iron ions due to the current, and the iron ions will immediately react with water to turn into a turbidity of yellow (red) brown iron hydroxide. For example, if the anode of the electrolyzer is replaced with Aluminum rods will release aluminum ions and react with water to turn into milky aluminum hydroxide turbidity. It can be seen that the turbidity produced by electrolysis does not come from the quality of tap water, but from the material used in the anode of the electrolyzer; Another way to prove it is to electrolyze the water produced by the water purifier in the same way after adding salt, the electrolysis phenomenon will definitely be the same as that of the tap water; this false electrolysis experiment will mislead the public and cause damage to the company's image , Tap water practitioners should clarify.

8. If the user has a water tower or pool, which water hygiene should be paid attention to?

Answer: Do not directly connect the pumping motor to the company's water supply pipe for pumping, because this will not only affect the water used by the neighbors, but also cause misconnection pollution. It will cause external sewage to flow into the water pipe and seriously pollute the public water. You should ask the user to change it to Indirect pumping means that the tap water is first allowed to flow into the reservoir and then pumped to the water tower by a motor.

Underground water tanks are susceptible to sewage inflow. Please change to above ground water tanks and seal them to prevent rats, cockroaches, small animals or reptiles from falling and dying and seriously affecting water hygiene.

Water towers should also be covered to avoid contamination as described above.

Gauze nets should be installed in the air vents of water towers or pools to prevent mosquitoes and other larvae from flying into the habitat.

The water tower or pool should be cleaned regularly to avoid algae and odor.

9. How should ordinary residents judge if there is any problem with their tap water?

Answer: Residents can only judge the quality of tap water by its appearance, smell, and taste. Generally, the appearance of normal tap water should be clear, colorless, smellless (slightly disinfected water is normal), and it should not taste Odor (slightly disinfected water is normal).

10. What is effective residual chlorine? What is its relationship with human health?

Answer: Tap water is mostly disinfected with chlorine gas. When chlorine gas is dissolved in water, it will become hypochlorous acid or hypochlorite ion, which is commonly known as effective residual chlorine. Hypochlorous acid has extremely high oxidizing capacity. It can prevent the growth of bacteria (pathogenic bacteria) while staying in the water distribution pipe, so the effective residual chlorine plays an extremely important role in the safety and sanitation of tap water. For sanitation, it is necessary for tap water to contain effective residual chlorine, but our company will still keep it in a lower concentration range as much as possible. This is based on economic factors and higher concentration ranges. Although harmless to human health, sometimes Will make tap water have a similar disinfection water taste.

water test paper