Running water is the water produced by waterworks after purification and disinfection that conforms to the corresponding standards for people's lives and production. Domestic water is mainly drawn from rivers, lakes, groundwater and surface water through the water pump station, then treated in accordance with the relevant national sanitary standards for domestic drinking water. After sedimentation, disinfection, filtration and other technological processes, and finally flowed to each user through the distribution pump station.

The historical development

Running water is a kind of drinking water produced by professional equipment through many complicated technological processes. The treatment for running water is as follows:

Firstly, water must be drawn from rivers and lakes to waterworks (Different region has different water intake, and water sources directly affect the quality of drinking water in a region);

After coagulating, precipitating, filtering, flowing into the clear water pool and disinfecting, the running water is fed into the water pipeline through the water supply pump at high pressure. The general main pipelines use prestressed concrete pipes, steel pipes, PE pipes, ductile iron pipes and other pipes;

Finally, it is diverted to the users’ taps. To enter the users’ home, the whole process has to go through several water quality tests, and even more some places have to go through secondary pressure, secondary disinfection.

The method of disinfection

Now, the disinfection for running water mostly uses chlorination pulping process, the main purpose for the chlorination of public water supply is to prevent transmitting water diseases. Till now, this method has more than 100 years of history, with a perfect production technology and equipment. Chlorine for water disinfection has the advantages of good effect, low cost, and almost no harmful substances. However, after understanding and studying the theoretical data, it is found that chlorine gas has some disadvantages in the disinfection of running water. Chlorination disinfection of running water can produce carcinogens. At present, some experts have put forward many improvement measures.

Chlorine gas dissolves in water and reacts with water to form hypochlorous acid and hydrochloric acid. Hypochlorous acid plays a major role in the whole disinfection process. For the inorganic substances that produce odors, it can thoroughly oxidize and disinfect them. For the natural substances that have life, such as algae and bacteria, it can penetrate the cell wall, oxidize their enzyme system (enzymes are biocatalysts) and make them inactive, so that the life activities of bacteria are blocked and die. Hypochlorous acid itself is close to neutral, easy access to bacterial and show good sterilization effect, hypochlorous acid ions also have certain disinfection effect, but it is difficult to close to negatively charged bacteria (bacteria) negatively charged, so compared with hypochlorous acid, its sterilization effect are much worse, so chlorine disinfection effect is better than using bleach disinfection.

At this stage, the disinfectants, except chlorine gas, also have chlorine dioxide, and ozone. The use of alternative disinfectants can reduce the production of harmful substances and improve the treatment efficiency at the same time.

At present, the safe method of running water disinfection in the world is ozone disinfection, but this method is too expensive. What’s more, the ozone-treated water has limited retention time, as to how long it can be retained, there is no exact concept. So only a handful of countries are using it now.

Some problems in running water

Heavy metal pollution

Surface water resources: About 50% of water resources in China are polluted, hundreds of organic compounds and heavy metal ions enter into the water sources. Underground water sources: Metallic elements, such as fluorine, arsenic, iron and manganese and etc., exceed the standards.

Inferior quality of water pipes

From the point of water quality, the old waterpipes, leaking seriously and bursting frequently, easily cause secondary pollution.

Secondary pollution events

The secondary pollutants are mainly microorganisms, which can be killed by boiling water.

In many countries, it is very difficult to convert running water to drinking water, the boiling water can kill microorganisms, but can’t remove organic pollutants and heavy metal ions.

Many of organic pollutants, if accumulate to a certain extent in the human body, may cause cancer, teratogenesis and mutagenesis.

Running water can convert to drinking water through the use of commercial and domestic water filter. The PP filter cartridge can remove the impurities and rusty in the water. The activated carbon filter cartridge can remove residual chlorine, and the high grade activated carbon can have the effect of improving taste. It can remove and inhibit bacteria and microbes by using reverse osmosis technology and ultraviolet sterilizer. This is one of the main reasons that kinds of household filtering equipment gained popularity.