What is water?

Water (H2O) is an inorganic substance composed of hydrogen and oxygen, and it is a colorless and odorless transparent liquid at normal temperature and pressure. In nature, pure water is very rare. Water is usually a solution of acid, alkali, salt and other substances, and is still customarily called water. Pure water can be obtained by several distillations with platinum or seasonal utensils. Of course, this is pure water in a relative sense, and it is impossible to be absolutely free of impurities. Water is a substance that can be converted between liquid, gas and solid. Solid water is called ice; The state of gas is called water vapor. When the temperature of steam is higher than 374.2℃, gaseous water cannot be converted into liquid water by pressurization.

At 20℃, the thermal conductivity of water is 0.006 J/s? cm？ K, the thermal conductivity of ice is 0.023 J/s? cm？ K, when the density of snow is 0. 1× 103 kg/m3, the thermal conductivity of snow is 0.00029 J/s? cm？ K at 3.98℃, the maximum density of water is 1× 103kg/m3. When the temperature is higher than 3.98℃, the density of water decreases with the increase of temperature. At 0 ~ 3.98℃, water does not obey the law of thermal expansion and cold contraction, but its density increases with the increase of temperature. At 0℃, the density of water is 0.99987× 103 kg/m3, and the density of ice is 0.9 167× 103 kg/m3. So ice can float on the water.

Water has strong thermal stability. When steam is heated above 2000K, only a small amount of water will be dissociated into hydrogen and oxygen, but water will be dissociated into hydrogen and water when it is electrified. It has great cohesion and surface tension. Except mercury, the surface tension of water is the largest, which can produce obvious capillary phenomenon and adsorption phenomenon. Pure water is extremely weak in conductivity, while ordinary water contains a small amount of electrolyte and has conductivity.

Water itself is also a good solvent, and most inorganic compounds are soluble in water.

At -2 13. 16℃, water molecules will show hydrophobicity.

Physical properties:

Molar mass:18.05438+053g/mol.

Density: water 0.998g/cm3 (20 degrees), ice 0.92g/cm3.

Melting point: 0 degree 273. 15k

Boiling point: 100 degrees 373. 15K( 1 at standard atmospheric pressure)

Specific heat: 4. 184 joules/(g g)

water cycle

The biosphere can be divided into hydrosphere, atmosphere and lithosphere. Water circulates in the above areas as follows:

1. It can also evaporate from animals and plants into the air of the ocean or other water bodies;

2. Sink into the ocean from the sky and enter the ocean from land runoff;

3. Most of the water vapor evaporates from the ocean and returns to the ocean, but the wind blows the water vapor across the land and flows back to the ocean from the land runoff, which is about 36Tt per year. Water evaporates from land by 7 1Tt every year. There is 107Tt precipitation every year in the following forms: the most common are rainfall, hail, fog and dew. Concentrated water can reflect sunlight to form a rainbow.

Water in Chinese characters

(pictographic. Oracle Bone Inscriptions glyph. The middle is like a water vein, and the sides are like running water. "Water" is the radical of Chinese characters. From the word water, it refers to the name of a river or water conservancy, or the direction of water flow, or the nature and state of water. Original meaning: The liquid falling from the clouds in the form of rain is colorless, odorless and transparent, forming rivers, lakes and oceans, and its molecular formula is H2O, which is the main component of all living things).

1. Same meaning [water]

Water, yes. -Shuo Wen

Water, yes. Yes, yes. The world is not equal to water. -"Explanation of name"

Cold accumulated in yin is water. -Huainanzi Astronomy

The five elements say water. -"Book Hongfan"

Where water comes out of the plain, it is a flood. -"Zuo Zhuan, the first year of Huan Gong"

Water is pure and clean. -Book of Rites Quli

Ice, water, but colder than water. -"Xunzi Persuades to Learn"

Liu Yuzhou's royal family has outstanding talents and is admired by all the people. -Song Sima Guang's History as a Mirror

Another example: water hammer (small appliance for boiling water); Shuitouer (storm); Moist water (moisture; Moisture); Halo (water sickness); Shuicheng (a small water tank next to the inkstone for storing and grinding ink); Water ebbs and flows (metaphor for inner stability); Spray peach blossoms with water (figuratively good-looking); Mr. Shui Jing (referring to Si Mahui in the Three Kingdoms, as clear as a mirror); Mixed land and water. Food and food are displayed together); Brief introduction of water (brief introduction of cities near water); Water vortex (vortex in water); Water pavilion (pavilion or post station by the water)

2. Especially rivers [rivers]

In Mae Shui. -"Shi Qin Feng Jiajian"

She has been taking care of an empty boat in the estuary, with no companions except the bright moon and cold water. -Tang Juyi's Pipa Trip (Preface)

Another example: Shuikou (ferry); Water branch (tributary of a river); Shui Zhi (a book about water system); Water butterfly (refers to the literature describing water system); Shui Gu (Shanhegou); Water tail (the end of a river); Water rat (thief stealing a boat); Water (about river water conservancy); Water prohibition (river prohibition); Water sink (river interchange)

3. Generally refers to all waters [waters]

The water house is deep, I am ignorant, and the master is not far away. What would he do? -Don Lee Wei Chao's Liu Yichuan

Liu Bei and Zhou Yu go hand in hand. -Song Sima Guang's History as a Mirror

Another example: land and water (the land and water Dojo in Buddhism); Shui Bo (Hu Ze); Shuiju (living in a water town); Water shovel (ditch); Water king (another name for the sea); Water Bo (the legendary water god; River); Water hotel (spend the night on the water; Accommodation in water); Water veins (waterways, underground undercurrents); Poor water (due to too much rain, water accumulates in the field or flows to the ground)

4. Fruit juice and liquid [liquid].

Such as: water ceremony (fruit bait and other gifts); Fruit candy (candy made of fruit juice); Ink; Saliva; Tears; Potions; soda

5. floods; flood

Therefore, there were nine years of water and seven years of drought in Tang Dynasty. -Han Chaocuo "On Your Millet"

Yue: Is there a law in heaven and earth? Yue: Floods, droughts and epidemics are also ways to regulate heaven and earth. -Hong Qing Ji Liang's "Ping Ping"

Another example: water storage (facilities to prevent floods); Water dike (flood wall)

5. Star name [Morning Star].

Such as: stachys (constellation name. Ancient astronomers collectively referred to Polaris and the Seven Nights)

6. Official name [official name].

Such as: Shuiyu (ancient official name. Act in charge of Kawasawa); Water conservancy official (official in charge of water resources management and fishery tax)

7. Silver content in currency. The fineness of silver is converted into the name of currency exchange subsidy and remittance fee [silver content in coins].

Such as: discount; Detain water; Collecting water; Water silk (secondary silver)

8. One of the five elements [water, one of the five elements]

Five elements: water, fire, wood, gold and earth. -"Book Hongfan"

9. Aquatic animals and plants.

For example, I can't afford to grow water in the field, and the lake has recently collected rent.

10. Always refers to the painful life situation of nuns and prostitutes [deep distress].

Such as: water affairs bureau (formerly referring to prostitutes in brothels); Water passengers (dock vendors, also known as traffickers)

1 1. Extra income or extra expenses.

"Making money" means "[extra income]".

12. refers to the water army [troops fighting on water]

When all the people saw the book that the water level was 800 thousand, they were frightened. -Song Sima Guang's History as a Mirror

13. [Aquarium] A minority in China lives in Guizhou Province.

14. Last name

15. Five strokes are divided into two.

The source of water

The earth is the only planet covered with liquid water among the eight planets in the solar system. There are great differences in academic circles about the origin of water on the earth, and there are dozens of different theories of water formation at present. Some people think that in the early days of the earth's formation, hydrogen in the primitive atmosphere was oxidized into water, and water vapor gradually condensed to form the ocean; There is also a view that water originally existed in the nebula material that formed the earth. Another view is that silicate and other substances in the original crust react under the influence of volcanoes and precipitate water. There are also views that comets and meteorites attracted by the earth are the main sources of water on the earth, and even now the water on the earth is still increasing.

Impact on climate

Water can regulate the climate. Water vapor in the atmosphere can block 60% of the earth's radiation and protect the earth from being cooled. Ocean and land water bodies can absorb and accumulate heat in summer, so that the temperature will not be too high; Heat can be released slowly in winter, so that the temperature will not be too low.

Water on the surface of the ocean and the earth evaporates into the sky to form clouds. Water in the clouds falls into the rain through precipitation and turns into snow in winter. Water falling to the surface seeps into the ground to form groundwater; Groundwater gushes out from the stratum again, forming spring water, which flows into the sea through streams and rivers. Form a water cycle.

Precipitation activities such as rain and snow have an important influence on climate formation. In temperate monsoon climate, monsoon brings abundant moisture, forming obvious dry and wet seasons.

In addition, in nature, due to different climatic conditions, water will appear in the form of hail, fog, dew and frost, which will affect the climate and human activities.

Impact on geography

0% of the earth's surface is covered with water. Seen from the sky, the earth is a blue planet. Water erodes rock and soil, scours and silts rivers, transports sediments, builds plains and changes the surface morphology.

The surface water of the earth constitutes the hydrosphere, including oceans, rivers, lakes, swamps, glaciers, snow, groundwater and water in the atmosphere. Because the water injected into the ocean contains a certain amount of salt, and it accumulates and evaporates all the year round, the sea and ocean water are salty and cannot be directly drunk. The water in some lakes is also salty. The largest body of water in the world is the Pacific Ocean. The Great Lakes of North America are the largest fresh water system. The Caspian Sea on Eurasia is the largest saltwater lake.

The volume of water on the earth is about10.36 billion cubic kilometers, of which

Ocean accounts for1320,000,000 cubic kilometers (or 97.2%).

Glaciers and ice sheets account for 25 million cubic kilometers (or 1.8%).

Groundwater accounts for13 million cubic kilometers (or 0.9%).

Freshwater in lakes, inland seas and rivers accounts for 250,000 cubic kilometers (or 0.02%).

Water vapor in the atmosphere accounts for 13 000 cubic kilometers (or 0.05438+0%) at any given time.

Influence on life

Life on earth first appeared in water. Water is an important part of all living things. Water in the human body accounts for 70%; Jellyfish is 98% water. A large number of aquatic plants and other aquatic organisms live in the water.

Water is beneficial to chemical reactions in the body and also plays the role of transporting substances in the living body. Water plays an important role in maintaining the stability of biological body temperature.

Types of water

Different disciplines have different names for water:

According to the different water quality, it can be divided into:

Soft water: Water with hardness below 8 degrees is soft water.

Hard water: water with hardness higher than 8 degrees is hard water. Hard water will affect the effect of detergent, and heating with hard water will have more scale.

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

Fresh water.

salt water

In addition, there are: biological water: water in different States existing in various living systems.

Natural water:

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.

In addition, water also includes sweat, salt water, urine, distilled water, etc.

Water-related chemical reactions

Ionization of water and pH value of solution

Water is a very weak electrolyte, which can ionize weakly: H2O+H2O? H3O++OH- H3O+ is usually abbreviated as H+

Ionic product kw of water = [h+] [oh-]

At 25 degrees, kw =/kloc-0 /×10-14.

pH=-log 10([H+])

PH<7, the solution is acidic, pH=7, the solution is neutral, pH >；; 7. The solution is alkaline.

Water-soluble acidic oxides or basic oxides can react with water to generate corresponding oxyacids or bases. The neutralization reaction between acid and alkali produces salt and water. Under the action of electric current, water can be decomposed into hydrogen and oxygen. Alkali metals will burn when exposed to water.

Under the action of catalyst, inorganic matter and organic matter can be hydrolyzed with water;

Hydrolysis of organic matter: some atoms or groups in organic matter molecules are replaced by hydrogen atoms or hydroxyl groups (-OH) of water molecules, such as methyl acetate hydrolysis;

Hydrolysis of inorganic substances: usually hydrolysis of salts, such as sodium acetate, a weak acid salt, which combines with H+ in water to form a weak acid, making the solution alkaline;

In addition, water itself can also be used as a catalyst.

Problems and Countermeasures of Shortage of Freshwater Resources

The total water reserve on the earth is about1.36x1kloc-0/8m3, but only 2.5% of it is fresh water except the salt water resources such as the ocean. Fresh water mainly exists in the form of glaciers and deep groundwater, and the fresh water in rivers and lakes accounts for only 0.3% of the total fresh water in the world.

The World Meteorological Organization pointed out at the beginning of 1996 that water shortage is the primary problem facing cities all over the world. It is estimated that by 2050, 46% of the urban population in the world will be short of water. For areas lacking water resources, water has surpassed the category of biological resources and become a strategic resource. Because of the scarcity of water resources, the possibility of water war is getting higher and higher.

In order to make the whole world care about the shortage of fresh water resources, the 47th United Nations General Assembly designated March 22nd as World Water Day.

Present situation of water in Beijing

Beijing is also a city with serious shortage of water resources. The calculation shows that Beijing's water resources reserves are 65.438+0.827 billion cubic meters, and foreign water resources reserves are 65.438+0.9/kloc-0.50 billion cubic meters, totaling 3.742 billion cubic meters/year, with a per capita of 366.8 cubic meters, accounting for only 65.438+03.8% of the national average and 65.433% 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 14.28% 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 Baiyang River Reservoir in Karamay, Xinjiang, rain and snow increased for four consecutive years in winter and three summers, which increased the storage capacity of Baiyang River Reservoir by 22. 6% per year.

At the initiative of experts to the municipal government, the municipal party Committee and municipal government attached great importance to it and decided to set up a leading group for weather modification in Beijing, with an office for weather modification, which was responsible for the planning, management, operational guidance, operation implementation and scientific research of artificial precipitation enhancement and hail suppression in the city. At the same time, it was decided to take artificial precipitation enhancement as a long-term strategic task and carry it out permanently.

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.

Utilization of water and present situation of water resources

Water is an important resource for human life, especially for agricultural irrigation, and the origin of human civilization is mostly in the big river basin. Early cities were generally built near the water to solve the problems of irrigation, drinking water and sewage. In human daily life, water plays an indispensable role in drinking, cleaning and washing. Water is also the basic element on which everything depends. However, with the development of social economy, the demand for water resources is increasing. Since the beginning of this century, the global fresh water consumption has increased by 8 times, including agricultural water consumption by 7 times, urban water consumption by 12 times, industrial water consumption by 20 times, and global fresh water consumption by 5% every year. At present, there are about 90 countries in the world, 40% of the population is in water shortage crisis, 3 billion people lack water sanitation facilities, and 3 million to 4 million people die of water-related diseases every year. By 2025, the water crisis will spread to 48 countries and 3.5 billion people will be trapped by water. The deterioration of ecosystem and the destruction of biodiversity caused by water crisis will also seriously threaten human survival. In the past 50 years, there have been 507 conflicts caused by water, including 37 violent conflicts, and 2 1 turned into military conflicts. Experts warn that with the increasing shortage of water resources, the competition for water will intensify. The water crisis has become a worldwide concern. 1At the beginning of 996, the World Meteorological Organization pointed out that water shortage is the primary problem facing cities all over the world. It is estimated that by 2050, more than two-thirds of the world's population will live in cities, and 46% of the world's urban population will be short of water. It is necessary to balance the relationship between social and economic development and urban fresh water supply management, and carry out large-scale engineering construction of water resources storage, transportation and management. The British "Independent" said that the world's great rivers are drying up at an alarming rate, which will have devastating consequences for the future of human beings, animals and the earth. To make matters worse, the 20 longest rivers in the world are blocked by dams. 1/5 freshwater fish groups have been or are on the verge of extinction. On March 6th, 2006, the 4th World Water Forum opened in Mexico. In the World Water Development Report submitted to the General Assembly, the United Nations said that we have seriously changed the natural laws of global rivers. Also from the United Nations, a research report entitled "Comprehensive Assessment of the World's Freshwater Resources" said: If people continue to live like this, 30 years later, the number of people lacking water may reach 2/3. According to media reports, 60% of drinking water pipes in some cities in third world countries are seriously damaged and a lot of water is lost. According to the survey of the United Nations, the leakage water consumption of Manila, the capital of the Philippines, is close to 58% of its total water supply. In Singapore, where management measures are good, there is also a leakage rate of 8%; The leakage rate of pipeline network in the United States and Britain is12%; The figure in China is 20%. There is no doubt that fresh water should be a scarce resource, however, in quite a few countries and people, this concept has not really formed.

With the development of science and technology, people build water conservancy projects to fight against natural disasters such as floods and waterlogging. Therefore, some special research fields related to water have been formed, such as hydraulics, hydrological science, water treatment and so on. , and even has produced water-based industrial aquaculture.

According to the British "Guardian" reported in February 15, although 70% of the earth's surface area is water, only 3% is fresh water resources. Only 1% of fresh water can be used by human beings, and most of the rest is either frozen in the polar regions of the earth or buried deep underground, making it difficult to exploit. Since the 1940s, the human demand for water has quadrupled, and it is still increasing endlessly.

According to statistics, one fifth of the world's population, namely 1 1 100 million people, currently have no access to safe drinking water, and another 2.4 billion people lack good sanitation facilities. Five million people die every year, among which 15 seconds/children die.

In the 20th century, half of the wetlands in the world disappeared forever, while groundwater resources were exhausted due to pollution or over-exploitation. The water crisis threatens every country and region in the world. For example, Britain has become the country with the worst water crisis in Europe.

This cheap raw material is widely used in industrial production and chemical production. However, the arbitrary discharge of untreated wastewater will cause water pollution. In order to solve this problem, sewage treatment becomes very necessary. (See Water Pollution and Sewage Treatment. )

Ranking of water resources indicators in the world

1.Top 10 water resources.

Brazil, Russian Federation, USA, Indonesia, Canada, China, Bangladesh, India, Venezuela and Colombia.

2. The per capita water resource is 10.

Kuwait, Libya, Singapore, Saudi Arabia, Jordan, Yemen, Tunisia, Algeria, Burundi,

3. Former 10 water users

China, the United States, India, Pakistan, Russia, Japan, Uzbekistan, Mexico and Egypt.

4. Per capita water consumption before 10

Turkmenistan, Uzbekistan, Kyrgyzstan, Tajikistan, Azerbaijan, Pakistan, USA, Afghanistan.

5. Per capita annual water consumption after10

Solomon Islands, Haiti, Democratic Republic of Congo, Equatorial Guinea, Guinea-Bissau, Congo, Burundi, Uganda, Central African Republic, Benin.

According to statistics, China's total water resources is 2.8 trillion cubic meters, ranking sixth in the world. The per capita possession is 2340 cubic meters, which is only 1/4 of the world's per capita possession, ranking 109 in the world and being listed as one of the world's 13 water-poor countries. Among the more than 640 cities in China, there are more than 300 water-deficient cities and 0/08 cities with severe water shortage.

Development of water and agriculture

In 3000 BC, China

The oldest known irrigation technology is used for rice cultivation. Farmers build rice fields on all sides, similar to shallow ponds, and then take water from nearby streams for irrigation. This ancient technology is still widely used in Southeast Asia, East Asia and South Asia.

In 2000 BC, Egypt

The Egyptians invented the method of getting water from the river. They used a tool called orange syrup, that is, they easily lifted the bucket from the river with a crossbar. Water from the river irrigates farmland through canals. This orange is still used in Egypt, India and some other countries.

In 700 BC, Assyria

Senna Shirley, king of Assyria in the ancient East, planted rare plants such as fruit trees and cotton around the capital Nineveh. In order to irrigate these plants, he built a canal 10 km long and a stone trough to get water from the nearby mountains.

In 500 AD, Mexico

There are many swamp lakes around Tenoch, the former Mexican capital, in which the Aztecs built terraces. They spread fertile soil dug from the bottom of the lake on terraces and planted corn. Netted ditches around OTA ensure water for crops, and farmers can also sail through OTA.

Us ad 1870

Agricultural water in the arid Great Plains of the central United States can only rely on groundwater. When the settlers who have allocated all government land come there, they use the power of windmills to extract groundwater, then dig ditches and introduce the extracted groundwater into farmland for irrigation.

Israel, A.D. 1990

Water is the basis of survival in desert areas. Drip irrigation is an irrigation method in which a small hole is made in the water pipe and water is directly dripped into the soil next to the root of each plant. This method can minimize the loss of irrigation water. Make Israel a country with high utilization rate of water resources.

Treatment of drinking water

1. First filtration: the water flow introduced from rivers and other places is filtered through a filter screen to remove fish, leaves and garbage;

2. Adsorption: Alum is added into the water filtered for the first time to form viscous flocs, and particles such as soil and bacteria are attached to alum flowers, and then the alum flowers are precipitated and filtered;

3. Secondary filtration: when water flows through sand or gravel, algae, bacteria and some chemical components are filtered out (equivalent to the current household filter drinking machine);

4. Chlorination: adding chlorine to water to kill residual organic organisms;

5. Ventilation: air is forced into the treated water to drive away chlorine, reduce the smell and taste of water and ensure drinking safety;

6. Additional treatment: Sodium or lime can be added to soften hard water. Some communities add fluoride to prevent chlorine from corroding teeth.

(domestic) wastewater treatment

1. Primary treatment: the wastewater flows through the treatment equipment, and the flow rate slows down, causing large solid substances to precipitate. When water passes through the sedimentation tank, smaller particles sink to the bottom to form mud;

2. Re-treatment: In the trickling filtration system, the wastewater is filtered by gravel, and the surface of the gravel can be covered with a layer of bacterial community to decompose the waste in the sewage;

3. Additional treatment: Water is discharged into the open-air pond and naturally purified by sunlight and air. After entering the atmosphere, pure water vapor is formed. Chlorine is usually added before treated water is discharged again.

Effect of water on human body

Water is the source of life. Man's demand for water is second only to oxygen. If people don't take certain vitamins or minerals, they may live with diseases for weeks or years, but if there is no water, they can only live for a few days. This shows the importance of water to human survival.

The important component of human cells is water, which accounts for 60~70% of adult body weight. So what's the use of so much water for the human body?

1. People need water for all kinds of physiological activities. For example, water can dissolve various nutrients, and fat and protein can only be absorbed if they are suspended in water. Water flows endlessly between blood vessels and cells, transporting oxygen and nutrients to tissues and cells, and then discharging metabolic wastes from the body. In short, people's various metabolic and physiological activities are inseparable from water.

2. Water has a certain effect on body temperature regulation. When people breathe and sweat, they will excrete some water. For example, in the hot season, the ambient temperature is often higher than the body temperature, so people rely on sweating to evaporate some heat to lower their body temperature and avoid heatstroke. In cold weather, because of the great potential of water to store heat, the body temperature will not fluctuate obviously because of the low external temperature.

Water is still the lubricant in the body. It can moisturize the skin. When the skin is short of water, it will become dry, lose elasticity and look old. Some joint capsule fluid and serosa fluid in the body can prevent organs from being damaged by friction and can rotate flexibly. Tears and saliva are also lubricants for corresponding organs.

Water is the cheapest and most powerful magic medicine in the world. The health care and disease prevention functions of mineral water and electrolyte water are well known. Mainly because water contains ingredients beneficial to human body. When you have a cold or fever, drinking more boiled water can help you sweat, reduce fever and dilute toxins produced by bacteria in your blood. At the same time, the increase of urine is beneficial to accelerate the discharge of toxins.

5. Large area burns, severe vomiting, diarrhea and other symptoms, when the body loses a lot of water, it should be rehydrated in time to prevent severe dehydration and aggravate the condition.

Water in ancient world view

In the early days of civilization, people began to explore the composition or classification of various things in the world, in which water played an important role. The four elements put forward by the ancient west said that there was water; There are also water in the four major Buddhists; In China's ancient theory of five elements, water represents all liquids and things with flowing, moist and feminine properties.

Water worship

In human childhood, water has the ability to nurture and destroy, and its unpredictable temperament produces feelings of love and fear, which leads to water worship. By endowing water with the spirit of God, we pray that water can bring peace, harvest and happiness to mankind.

The traditional Dragon King in China deified water. Where there is water, there is the Dragon King, whose temples and churches are all over the country. Sacrificing the Dragon King and praying for rain are traditional beliefs and customs in China.

And colloquialism

Describe people who are not ambitious or do things well enough.

For example, that's how you mix water. You are so bad at it. )

High mountains and Running water

Guqin music During the Warring States Period, there was a story of Qin Le about high mountains and flowing water, so it was also said that "high mountains and flowing water" was written by Boya. The music score was first seen in The Secret Music of the Ming Dynasty (written by Zhu Quan at 1425). The solution of this score is: "Mountain Flowing Water is two songs, but there is only one. The first ambition is to care about mountains and rivers, saying that benevolent people are Leshan. The ambition of the future is to care about running water, which means that the wise are happy with water. The Tang dynasty is divided into two songs, regardless of section. The highest mountain is divided into four sections and eight sections of flowing water. " For more than 2,000 years, two famous guqin songs, Mountain and Running Water, together with the story of Boya guqin meeting a bosom friend, have been widely circulated among the people.

"Mountain Flowing Water" takes "Boya Guqin meets a bosom friend" as the main line, and there are many kinds of Le Shu. There are two kinds of Qin music and Zheng music, both of which have the same name and different styles.

With the development of Qin's performing arts since Ming and Qing Dynasties, "mountain" and "water" have undergone great changes. The legendary secret score is not segmented, but later the piano score is segmented. Among the numerous music scores since Ming and Qing Dynasties, Running Water, which was adapted by Zhang Kongshan, a pianist of Sichuan School, was included in Tian Wen Song Score (1876) compiled by Tang Dynasty in Qing Dynasty. The sixth paragraph of the technique of "rolling, brushing, dialing and noting", also known as "seventy-two rolling and brushing water", is widely used because of its vivid image and blending of scenes. According to the Qin family's textual research, before the publication of Tianwenge's piano score, there was no sixth paragraph played by Zhang Kongshan in all the scores, and the whole song had only eight paragraphs, which was consistent with the solution of the magical secret score, but Zhang Kongshan passed it on. I'm Yan Xin? Oh, danger, are you like a seed?

There is also a guzheng song "Mountain Stream and Running Water", the music is quite different from piano music, and it is also based on "Boya Guqin meets a bosom friend". There are many genres of music books. The most widely circulated and influential is the Biography of Zhejiang Wulin School, with elegant melody and meaningful charm, which has the appearance of "majestic mountains and flowing water".

Lu Pai's "Mountain Flowing Water" is an ensemble of four ditties: Qin Yun, the wind shaking the bamboo, the bell ringing at night and the rhyme, also known as four paragraphs and four paragraphs of brocade.

The Mountain Flowing Water of Henan School is based on the folk song Old Liu Ban, with a fresh and lively rhythm. Folk artists often play this song when they meet for the first time to show respect and make friends. These three songs and Guqin music "Mountains and Running Water"