What is the great role of water in modern society? Water resources situation in China (or region).

Soft water: Water with hardness below 8 degrees is soft water. (No or little calcium and magnesium compounds)

Hard water: water with hardness higher than 8 degrees is hard water. (containing more calcium and magnesium compounds). Hard water will affect the effect of detergent; The high hardness of boiler water is very dangerous, which not only wastes fuel, but also causes local overheating of the pipeline in the boiler, which is easy to cause deformation or damage of the pipeline. Long-term drinking is harmful to people's health. Heating with hard water will cause more scale.

According to the content of sodium chloride, drinking water can be divided into:

Fresh water, salt water and biological water: water in different states existing in various living systems. Natural water: fish soil water: water stored in soil.

Groundwater: Water stored underground. Ultra-pure water: water with high purity, mostly used in integrated circuit industry.

Crystal water: also known as hydrated water. In crystalline matter, a certain number of water molecules are bound to ions or molecules through chemical bonds.

The chemical formula of heavy water is D2O, and each heavy water molecule consists of two deuterium atoms and one oxygen atom. Heavy water accounts for less than two ten thousandths of natural water, and the heavy water obtained by electrolysis is more expensive than gold. Heavy water can be used as moderator and heat carrier for atomic reactors.

The chemical molecular formula of super heavy water is T2O, and each heavy water molecule consists of two tritium atoms and one oxygen atom. Ultra-heavy water is extremely rare in natural water, and its proportion is less than one billion. The production cost of ultra-heavy water is tens of thousands of times higher than that of water.

The chemical formula of deuterated water is HDO, and each molecule contains one hydrogen atom, one deuterium atom and one oxygen atom. Not very useful.

Present situation of water in Beijing

China and Beijing are also cities with serious water shortage. The calculation shows that Beijing's water resources reserves are 65.438+0.828 billion cubic meters, and foreign water resources reserves are 65.438+0.9/kloc-0.30 billion cubic meters. The total water resources in Beijing is 3.724 billion cubic meters per year, with a per capita of 366.8 cubic meters, accounting for only 65.438+03.6% of the national average and 65.438+0.20% of the world average. Because Beijing's underground is almost a closed basin, its groundwater inflow and outflow is zero. After years of observation, the outflow of surface water in Beijing accounts for about 14.29% of the total annual precipitation, that is,1438 million cubic meters, with various losses of 332 million cubic meters. Therefore, the actual available water quantity of water resources in Beijing is only19.72 million cubic meters.

In order to alleviate the contradiction of water shortage in Beijing, some meteorologists in Beijing attended a meeting sponsored by Beijing Association for Science and Technology and Beijing Meteorological Society from 65438 to 0990 to discuss how to alleviate the water shortage problem. Experts attending the meeting reached a consensus that it is a new way with less investment and quick results to explore the use of cloud and water resources in the air for artificial precipitation enhancement. Because after the first experiment of artificial precipitation enhancement by aircraft in the United States 1946 was successful, nearly 100 countries or regions have conducted experiments of artificial weather modification. Israel has carried out artificial precipitation enhancement in the western coastal areas. According to strict physical statistics, the increased rainfall is 15%. From 65438 to 0958, China carried out artificial precipitation enhancement in Jilin Province for the first time. In the past 30 years, Jilin, Inner Mongolia and other provinces and regions have made remarkable achievements. Fujian Gutian reservoir area insisted on artificial precipitation enhancement experiment 12 years, with an average precipitation increase of 23%; In the mountainous area of the upper reaches of Baiyanghe Reservoir in Karamay, Xinjiang, artificial precipitation enhancement has been carried out for four years in winter and three summers in succession. Snowfall increased the storage capacity of Baiyanghe Reservoir by 22. 6% per year.

At the initiative of experts to the municipal government, the municipal party Committee and municipal government decided to set up a leading group for weather modification in Beijing, with an office for weather modification, which is responsible for the planning, management, operational guidance, operation implementation and scientific research of artificial precipitation enhancement and hail suppression in the city, and at the same time, it is determined that artificial precipitation enhancement will be a long-term strategic task.

Artificial precipitation enhancement is to make use of rainy weather conditions, that is to say, it can rain if there are clouds (clouds below 0℃). Through manual intervention, the water droplets in the cloud are catalyzed by a catalyst (liquid nitrogen), which makes the liquid water droplets appear ice crystals, which makes the local temperature of the cloud below 0℃ drop rapidly and causes image changes. In the case of water droplets and ice crystals, the water vapor pressure on the ice surface is lower than that of liquid water droplets, which makes the water vapor molecules on the surface of liquid water droplets move to the ice surface and attach to the ice particles, making the ice particles grow into small snowflakes. The higher the falling temperature, the smaller the water droplets gradually become. In the natural state, liquid water droplets are difficult to turn into ice crystals, which can be turned into ice crystals through manual intervention, and precipitation can be increased under the condition of natural precipitation.

Beijing is located in North China Plain, bordering Bohai Sea in the east, Taihang Mountain in the west, Jundu Mountain in the north and Hebei Plain in the south, with a warm temperate semi-humid and semi-arid climate. The average annual precipitation is 400-600 mm, and 80% of the annual precipitation is concentrated in June-September, especially in July-August, so we choose to operate at this time to increase surface runoff and increase water for Guanting and Miyun Reservoir.

Water on the earth

The total reserves of water on the earth are 65.438+03.86 billion cubic meters, of which fresh water only accounts for 0.9%; Lakes, rivers and shallow groundwater, which are closest to human life, only account for 0.02% of the total fresh water reserves.

Treatment of drinking water

1. First draw water from rivers and other places to the treatment plant, and at the same time filter out large objects with a filter screen;

2. Alum is mixed into the water filtered by big things, and the soil and other things are bonded with alum to form alum flowers, and then the water is precipitated and filtered out;

3. When the water flows through the sand and gravel, some organic matter and chemical components are filtered out (equivalent to the current household filter drinking machine);

4. Add chlorine to the water to kill the remaining microorganisms;

5. Sodium or lime can be added to soften hard water, and sometimes ventilation is used to remove chlorine from water.

Classification of water pollution

There are two kinds of water pollution: one is natural pollution; The other is man-made pollution. At present, man-made pollution is the most harmful to water bodies. According to different impurities, water pollution can be divided into chemical pollution, physical contamination pollution and biological pollution.

chemical pollution

Water pollution caused by chemical impurities. According to the specific pollution impurities, chemical pollution can be divided into six categories:

(1) Inorganic pollutants: Inorganic pollutants that pollute water bodies include acids, alkalis and some inorganic salts. Acid-base pollution changes the pH value of water, hinders the self-purification of water, corrodes ships and underwater buildings, and affects fisheries.

(2) Inorganic toxic substances: Inorganic toxic substances that pollute water bodies are mainly substances with potential long-term effects such as heavy metals, mainly elements such as mercury, cadmium, lead and arsenic.

(3) Organic toxic substances: The organic toxic substances that pollute water bodies are mainly various organic pesticides, polycyclic aromatic hydrocarbons and aromatic hydrocarbons. Most of them are synthetic substances with stable chemical properties, which are difficult to be biodecomposed.

(4) Aerobic pollutants: Organic substances such as carbohydrates, protein, fats, phenols and alcohols contained in domestic sewage and some industrial wastewater can be decomposed by microorganisms. In the process of decomposition, a lot of oxygen is needed, so it is called aerobic pollutant.

(5) Plant nutrients: mainly plant nutrients such as nitrogen and phosphorus in domestic and industrial sewage, and residual nitrogen and phosphorus in farmland drainage.

(6) Oil pollutants: mainly refer to the pollution of water by oil, especially the pollution caused by offshore oil production and tanker accidents.

Physical contamination

Physical contamination includes:

(1) suspended matter pollution: suspended matter refers to insoluble matter contained in water, including solid matter and foamed plastics. They are caused by the leakage of domestic sewage, garbage and waste from mining, quarrying, construction, food processing and paper making into water or farmland soil erosion. Suspended matter affects the appearance of water, hinders the photosynthesis of plants in water and reduces the dissolution of oxygen, which is unfavorable to aquatic organisms.

(2) Thermal pollution: If the cooling water produced by various industrial processes is not directly discharged into the water body, it may lead to an increase in water temperature, a decrease in dissolved oxygen content, and an increase in the toxicity of some toxic substances in the water, thus endangering the growth of fish and aquatic organisms.

(3) Radioactive pollution: Due to the development of atomic energy industry, the exploitation of radioactive mineral deposits, the establishment of nuclear tests and nuclear power plants, and the application of isotopes in medicine, industry, scientific research and other fields, radioactive waste water and waste have increased greatly, causing certain radioactive pollution.

biological pollution

Domestic sewage, especially hospital sewage and some industrial wastewater, often brings in some pathogenic microorganisms after polluting water bodies. For example, some pathogenic bacteria, such as typhoid fever, paratyphoid fever and cholera bacteria, which originally existed in human and animal intestines, can enter the water body through the pollution of human and animal feces and spread with the water flow. Some viruses, such as hepatitis virus and adenovirus, are often found in polluted water. Some parasitic diseases, such as amebic dysentery, schistosomiasis and leptospirosis, can also be transmitted by water. Preventing water pollution by pathogenic microorganisms is also an important task to protect the environment and human health.

waste water treatment

1. When the wastewater flows through the sedimentation tank, the solid will settle down;

2. In trickle filtration, wastewater flows through gravel for filtration, and the surface of gravel can also be covered with bacteria to decompose waste in sewage;

3. Other ingredients can be added to the water to drive away the chemical ingredients;

Water discharged into an open-air pond can be purified naturally. Too many questions, too few, shorten it for me.

Answer groundwater: water stored underground ultra-pure water: water with extremely high purity, which is mostly used in the integrated circuit industry.

Crystal water: also known as hydrated water. In crystalline matter, a certain number of water molecules are bound to ions or molecules through chemical bonds.

The chemical formula of heavy water is D2O, and each heavy water molecule consists of two deuterium atoms and one oxygen atom. Heavy water accounts for less than two ten thousandths of natural water, and the heavy water obtained by electrolysis is more expensive than gold. Heavy water can be used as moderator and heat carrier for atomic reactors.

The chemical molecular formula of super heavy water is T2O, and each heavy water molecule consists of two tritium atoms and one oxygen atom. Ultra-heavy water is extremely rare in natural water, and its proportion is less than one billion. The production cost of ultra-heavy water is tens of thousands of times higher than that of water.

China and Beijing are also cities with serious water shortage. The calculation shows that Beijing's water resources reserves are 65.438+0.828 billion cubic meters, and foreign water resources reserves are 65.438+0.9/kloc-0.30 billion cubic meters. The total water resources in Beijing is 3.724 billion cubic meters per year, with a per capita of 366.8 cubic meters, accounting for only 65.438+03.6% of the national average and 65.438+0.20% of the world average. Because Beijing's underground is almost a closed basin, its groundwater inflow and outflow is zero. After years of observation, the outflow of surface water in Beijing accounts for about 14.29% of the total annual precipitation, that is,1438 million cubic meters, with various losses of 332 million cubic meters. Therefore, the actual available water quantity of water resources in Beijing is only19.72 million cubic meters.

In order to alleviate the contradiction of water shortage in Beijing, some meteorologists in Beijing attended a meeting sponsored by Beijing Association for Science and Technology and Beijing Meteorological Society from 65438 to 0990 to discuss how to alleviate the water shortage problem. Experts attending the meeting reached a consensus that it is a new way with less investment and quick results to explore the use of cloud and water resources in the air for artificial precipitation enhancement.

Beijing is located in North China Plain, bordering Bohai Sea in the east, Taihang Mountain in the west, Jundu Mountain in the north and Hebei Plain in the south, with a warm temperate semi-humid and semi-arid climate. The average annual precipitation is 400-600 mm, and 80% of the annual precipitation is concentrated in June-September, especially in July-August, so we choose to operate at this time to increase surface runoff and increase water for Guanting and Miyun Reservoir.