Hardness of water quality is a property of water resistance and soap bubble. It is an old concept used to describe the content of calcium and magnesium in water. There are different kinds of hardness (total hardness, carbonate hardness and other hardness), and there are different concepts and definitions in different countries.

Hardness salts generally include ca2+, mg2+, fe2+, mn2+, sr2+, te3+, al3+, etc. which are easy to form insoluble metal cations. In general natural water, ca2+, mg2+, and other ions are less. Therefore, the total ca2+, mg2+ in water is usually used as the definition of hardness.

Specifically, the total amount of Ca2 + and Mg2 + is called total hardness. According to the principle of hypothetical compound and considering the composition of anions in water, the hardness can be divided into carbonate hardness and non carbonate hardness.


In China, 82% of the people drink shallow wells and rivers, of which 75% are seriously polluted by bacteria and 160 million people are polluted by organic matters. For a long time, people have always thought that tap water is safe and hygienic. However, because of water pollution, today's tap water is not sanitary. A survey shows that 2221 kinds of chemical pollutants are detected in tap water all over the world, some of which are confirmed as carcinogens or cancer promoters. According to the drinking standard of tap water, China is still at a low level. The tap water can only be simply processed into drinkable water by precipitation, filtration, chlorination and disinfection. Chlorination of tap water can effectively kill bacteria, but also produce more halogenated hydrocarbon compounds. The content of these chlorinated organic compounds has doubled, which is the biggest source of human suffering from various kinds of gastrointestinal cancer. The components of urban pollution are very complex. In addition to heavy metals, the polluted water also contains many harmful residues such as pesticides, fertilizers and detergents. Even if the tap water is boiled, the above residues can not be removed, and the carcinogens such as nitrite and chloroform will be increased. Therefore, the safety factor of drinking boiled water is not high.
According to the latest information, only 23% of the drinking water in China's major cities meets the health standards, while the qualification rate of drinking water in small towns and rural areas is lower. It is urgent to ensure the quality of drinking water. Therefore, we should strengthen the monitoring of water pollution and set up water source protection areas. The mother river of the Yellow River was cut off for the first time in 1972. In 1997, it was cut off for 226 days and nearly 700 km of riverbed dried up. There are 300 tributaries of Haihe River, no river is dry, no river is odorous. The groundwater in North China is over exploited seriously, forming the largest groundwater funnel area in the world with an area of more than 70000 square kilometers. The ground is sinking and the sea water is invading. Among the 668 cities in China, more than 400 are short of water supply and more than 100 are seriously short of water. Since the late 1990s, the rate of land desertification has increased to more than 3400 square kilometers per year. What's more, China's total water resources are still declining. In 1997, the total volume was 2785.5 billion cubic meters, which dropped to 2413 billion cubic meters in 2004. Since the 1950s, more than 20 rivers in the upper reaches of the Yangtze River have shrunk by an average of 37.1%. The World Wide Fund for nature (WWF) published a report on March 19, listing the Yangtze River, the third longest in length and quantity in the world, as one of the 10 major rivers facing drying up in the world.

The prospect of China's water environment is worrying.

China is a country with shortage of water resources and frequent water disasters. The total amount of water resources in China ranks sixth in the world, with a per capita share of only 2500 cubic meters, about 1 / 4 of the world's per capita water, ranking 110th in the world, and has been listed as one of the 13 water poor countries by the United Nations.

China is one of the 13 water poor countries, and the water pollution is so serious, are you still drinking tap water?
Who poisoned our drinking water?

As the saying goes, we should find out who "poisoned" our drinking water before starting self-help

1、 Garbage disposal: the solution to garbage disposal in many areas is incineration or direct burial. Some domestic garbage, industrial garbage and hazardous wastes are buried underground without anti-seepage treatment, which will seep into the groundwater and cause pollution.

2、 Untreated feces: large scale livestock and poultry breeding can produce about 2 billion tons of feces every year, more than 90% of which will be directly discharged without pollution control measures.

3、 Pesticide irrigation: in China, 40 million tons of chemical fertilizer and 400000 tons of pesticide are used every year, and the chemical fertilizer and pesticide that cannot be absorbed by crops seep into groundwater. In rural areas, many farmers do not have the awareness of environmental protection. The consequence of excessive spraying of pesticides and fertilizers is that the wells are deeper and deeper, and the water use is more and more difficult.

4、 Over development leads to ground subsidence: in some areas, the ground collapses and sinkholes are frequently reported. In some areas with over development, the interlayer is damaged, and the sewage is more likely to penetrate into the groundwater and cause pollution.
5、 Illegal discharge of industrial sewage: illegal discharge of industrial pollution has formed a complete "industrial chain". The industrial sewage generated by high-risk polluting enterprises is transported to remote areas for discharge through third and fourth line intermediaries and workers under the guise of harmless treatment by second-line brokers (waste treatment companies).

The above is the root cause of water pollution. If we want to live and drink healthy water, we can only drink tap water, bottled water, mineral water or install water purification equipment.