Send your good work in the knowledge base is simple. Use the form below
Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.
Posted on http://www.allbest.ru/
Fresh water sources
Fresh water resources exist thanks to the eternal water cycle. As a result of evaporation, a gigantic volume of water is formed, reaching 525 thousand km 3 per year.
The rate of renewal determines the resources available to mankind. Most of the fresh water - 85% - is concentrated in the ice of the polar zones and glaciers. The rate of water exchange here is less than in the ocean, and is 8000 years. Surface water on land is renewed about 500 times faster than in the ocean. Even faster, in about 10 - 12 days, the waters of the rivers are renewed. Fresh waters of the rivers have the greatest practical value for mankind. Rivers have always been a source of fresh water. But in the modern era, they began to transport waste. Waste in the catchment area flows down the riverbeds into the seas and oceans. Most of the used river water is returned to rivers and reservoirs in the form of sewage. Fresh water reserves are potentially large. However, in any part of the world, they can be depleted due to unsustainable water use or pollution. The volume of water consumed depends on the region and standard of living and ranges from 3 to 700 liters per day per person. Water consumption by industry also depends on the economic development of the area. For example, in Canada, the industry consumes 84% of the total water intake, and in India - 1%. The most water-intensive industries are: steel, chemical, petrochemical, pulp and paper, and food. They take almost 70% of all water used in industry. On average, industry consumes about 20% of all water consumed in the world. The main consumer of fresh water is agriculture: 70-80% of all fresh water is used for its needs.
The total runoff of the rivers of the CIS (USSR) for the year is 4720 km 3. But water resources are distributed extremely unevenly. In the most populated regions, where up to 80% of industrial production lives and 90% of land suitable for agriculture is located, the share of water resources is only 20%. Many parts of the country are not sufficiently supplied with water. This is the south and southeast of the European part of the CIS, the Caspian lowland, south Western Siberia and Kazakhstan, and some other areas Central Asia, south of Transbaikalia, Central Yakutia.
Groundwater group subdivided into:
1. Artesian waters, which, with the help of pumps, rise to the surface from underground space. They can lie underground in several layers or so-called tiers, which are completely protected from each other. The chemical composition of water, as a rule, remains constant.
2. Infiltration water. This water is extracted by pumps from wells, the depth of which corresponds to the marks of the bottom of a stream, river or lake.
3. Spring water. About underground water, self-flowing naturally to the surface of the earth.
surface water:
1. River water. River water is the most polluted and therefore the last to be used. drinking water supply. It is polluted by the waste products of people and animals. To an even greater extent, pollution of river waters occurs with incoming sewage from workshops and industrial enterprises. . The preparation of river water for the purposes of drinking water supply is also difficult due to strong fluctuations in river water pollution, both in quantitative terms and in composition.
2. Lake water. This water, even extracted from great depths, is extremely rarely biologically impeccable and therefore must undergo special purification to drinking standards.
3. Water from reservoirs. We are talking about water from small rivers and streams, which are dammed upstream, where the water is the least polluted. Reservoir water is categorized in the same way as Lake water. In all cases, when choosing a method and volume necessary activities for water treatment, it is decisive how heavily this water is polluted and how high the self-cleaning capacity of this “storage drinking water».
4. Sea water. Sea water cannot be supplied to the drinking water supply network without desalination. It is extracted and treated only near the sea coast and on the islands, if it is not possible to use another source of water supply.
The problem of water consumption. Consumption is the main condition for human existence. enough water. The current situation is due to the fact that surface waters are mainly used as water sources, which make up only 1% of all fresh water reserves on Earth. In addition, it was found that within 1 year 50% of the world river flow go through different kinds human activity which include domestic needs, industrial production and crop irrigation (
Human water consumption, km 3 /year
For most of the development of human civilization during the 18 centuries, the daily human requirement was limited to 5 to 49 liters per day. The main reason for the limited water consumption was the presence of pathogenic microbes that were the cause of epidemics:
Typhoid, cholera, dysentery, poliomyelitis, hepatitis, gastroenteritis due to consumption of contaminated drinking water.
· Trachoma, leprosy, and other diseases of the skin and mucous membranes when washing with contaminated water.
· Malaria, yellow fever, due to the presence of infection carriers in the water.
Drinking water consumption increased dramatically after the appearance of the first centralized water treatment systems in the 18th and 19th centuries in Europe and Russia and has now reached 200-300 liters per person per day.
However, in 1985 a clean tap water at this level, only 1.1 billion people were supplied, while 0.8 billion people received 110 liters / day-person through standpipes, and the rest of humanity (4 billion) is content with a norm of 50-60 liters / day-person. Nevertheless, in general, over the 20th century, human water consumption has increased by an average of 20 times. The main consumption of drinking water is associated with the observance of sanitary and hygienic standards. spring artesian water infiltration
Structure of water consumption for household purposes of the urban population
Thus, in order to provide the population drinking water, (in each region of the Russian Federation), it is necessary to solve the problem of water quality management both in water sources and in treatment facilities. Obviously, the choice of water treatment and wastewater treatment technology will be carried out by comparing water quality data with their characteristics.
Hosted on Allbest.ru
...Similar Documents
Artesian waters - The groundwater enclosed between water-resistant layers and under hydraulic pressure. Artesian basin and artesian slope. Conditions for the formation of waters, their chemical composition. Pollution of artesian aquifers.
abstract, added 06/03/2010
Water in liquid, solid and gaseous state and its distribution on Earth. Unique properties water. The strength of hydrogen bonds. The water cycle in nature. Geographical distribution of precipitation. Precipitation as the main source of fresh water.
abstract, added 12/11/2011
The concept of the water cycle in nature, the water shell of the Earth, their structure, meaning. The essence of evaporation and condensation as physical processes, the conditions for their implementation. Features and composition of the annual water inflow. Sources of water movement on Earth.
presentation, added 11/23/2011
In what forms does water occur in nature? How much water is on earth. The concept of the water cycle in nature. How much water is contained in the human body. The concept of evaporation and condensation. Three aggregate states of water. The use of water in human activities.
presentation, added 02/19/2011
Characteristics of groundwater, which, according to their quality and purpose, are divided into drinking and technical (fresh and slightly brackish), mineral (medicinal), industrial (containing extractable concentrations of useful components) and thermal power.
abstract, added 06/03/2010
Pollution surface water. Underground tanks. Groundwater as part of the geological environment. Practical value groundwater. Characteristics of technogenic impact on groundwater (groundwater pollution). Groundwater protection.
abstract, added 04.12.2008
Construction and properties of the water consumption curve. Choice of a method for calculating daily water discharges based on the analysis of observational data on the features of the river regime. Methods of extrapolation and interpolation. Hydrological analysis of data on water and sediment runoff.
practical work, added 09/16/2009
Types of water in rocks, the origin of groundwater, their physical properties and chemical composition. Classification of groundwater according to the conditions of formation, gas and bacterial composition. Quality control technical water determining its suitability.
presentation, added 02/06/2011
Movement of water in zones of aeration and saturation, aquifers. Determination of the speed of groundwater movement, steady and unsteady movement. Filtration modeling methods. The flow of water to water intake facilities. Determining the radius of influence.
term paper, added 10/21/2009
A brief outline of the history of the development of hydrogeology. Destructive and creative geological activity of groundwater. Infiltration and condensation underground waters. Conditions for the formation and occurrence of groundwater in each zone of the underground hydrosphere.
Home water supply consists of the water source, water supply system, filters and plumbing fixtures in the home. The best source of water is an artesian well with a depth of 100 m. But obtaining permission to build such a well is very difficult and expensive. Therefore, usually one such well is drilled for the whole village. Further, the water is accumulated in the water tower and supplied to the plots (to the houses) through the summer (above-ground) or normal (underground) water supply.
Water supply is a system complex structures for taking water from natural sources, purifying it, storing the necessary supplies and supplying water of the appropriate quality to the consumer.
Sources of water supply are divided into surface and underground. Surface sources that can be used for water supply include rivers and reservoirs. Underground sources include soil and groundwater, interstratal (artesian) and springs (keys).
Water from a surface source contains various impurities - mineral and organic substances, as well as bacteria. Mineral impurities include particles of sand, clay, silt, salts dissolved in water, iron, organic - rotting substances of plant and animal origin. The appearance of bacteria in the water - the causative agents of various diseases - is associated with the ingress of sewage from residential villages and cities into rivers and lakes. River waters, as a rule, contain a large amount of suspended matter, especially during floods, as well as organic matter, microorganisms, including pathogenic bacteria, and a small amount of salts. The sanitary quality of river water is often low due to pollution by surface runoff. In reservoirs, water contains less suspended particles, but it is not transparent enough. The waters of fresh lakes are mostly transparent, but sometimes they are polluted by surface runoff.
Underground is a significant part of the water that has fallen to the ground in the form of precipitation and seeped through the soil. It penetrates deep into the earth, dissolves individual rocks and fills the pores between the particles of aquifers and free space to waterproof soils: clay, granite and marble. Groundwater occurs at various depths.
Verkhovodka- groundwater that accumulates in the upper layers of the soil, irregularities and depressions of impervious soils and do not form a continuous aquifer. Verkhovodka is usually found at shallow depths and is used to build rural log wells used for watering gardens and orchards. The water in the well is at the same level as the water in the ground. IN summer period wells can sometimes dry up. Verkhovodka is easily polluted by surface runoff and is unsuitable for the water supply of a country house.
Ground (non-pressure) water lie in a solid aquifer , under which there is an upper waterproof layer of soil. The water in drinking log village wells dug in the aquifer is at the same level as the water in the aquifer. This water can be used for water supply. Wells lowered into the aquifer rarely dry up.
Artesian (pressure) water are in deep aquifers that lie between impermeable soils. In fact, it is no longer a lake, but a river or a sea of water. If there is a lot of pressure in the aquifer, the water from the well springs up like a fountain.
key waters- this ground water that find a natural outlet to the surface of the earth. The springs are descending, when they come to the earth's surface from above as a result of the exposure of aquifers, for example, on the slopes of ravines and gullies, and ascending, when they come to the earth's surface from below from pressure layers.
Water used for household and drinking needs of the population must meet the following sanitary and hygienic requirements: be transparent, harmless to health, not contain pathogenic bacteria, and have no smell or taste. Water has these properties. underground sources(keys and especially "artesian" waters). Such water can be supplied to consumers without treatment. However, underground sources often contain a lot of salts and have significant hardness. Waters of underground sources with dissolved salts of calcium, sodium chloride, lime are called hard; they require softening, that is, the removal of excess dissolved salts (hard water from underground sources is the rule rather than the exception).
About 1500 million cubic kilometers of water is contained on our planet, of which approximately 10% is fresh water.
At the same time, from 110 to 190 million cubic kilometers of water is under the earth's crust, these are underground reservoirs. And from how deep these sources of water on earth, they are divided into surface and ground water.
Water basins located underground at depths of tens to hundreds of meters are a kind of vessels surrounded by solid rock, in which water is under high pressure. Water reservoirs that accumulate at depths of several meters are a favorable basis for wells from which people get water for domestic needs, but such water also has a disadvantage, due to its constant contact with the upper loose layers of soil, it is dirtier than that water which is much deeper.
A huge source of water on earth are our glaciers located in Antarctica and Greenland. It is in the region of 20 to 30 million cubic kilometers of fresh water. A considerable amount of fresh water falls to the earth from the atmosphere, in the form of precipitation formed due to evaporation from natural sources water on earth, it is still about 13 thousand cubic kilometers.
And how much fresh water is obtained annually from the world's oceans, through various physical and chemical methods. Undoubtedly, especially used sources of water on earth for their needs, mankind, today are, first of all, rivers and lakes. What is worth - the largest (and the cleanest in the world) natural storage of fresh water in Russia, the volume of which is 20 thousand cubic kilometers of water.
The composition of water in Baikal is approximately as follows:
Arsenic contains about 0.3 µg/l (MAC = 10 µg/l)
Lead in the region of 0.7 µg/l (maximum concentration limit = 10)
Mercury within 0.1 µg/l (maximum concentration limit = 1)
Cadmium approximately 0.02 µg/l (maximum concentration limit = 1),
6 thousand cubic kilometers of water on our planet is in you and me, living organisms, animals and plant organisms. Thus, our water Natural resources distributed throughout the planet. We are 80% liquid, and a violation of the water balance leads to sad consequences. We do not pay attention to how we exchange liquid with nature, through urine, sweat and exhaled tiny droplets of liquid. But in order for all this to take place, we draw this fluid from nature.
And no one wondered what if this exchange stops? In this case, dehydration occurs - dehydration of the body. The person begins to feel weak, the heartbeat quickens, shortness of breath and dizziness appear. When the body loses about 10% of the fluid from body weight, a person loses consciousness, his speech is disturbed, and hearing and vision also deteriorate. If the loss of fluid is 15-20% of body weight, then irreversible processes occur in the cardiovascular and nervous systems leading to death.
Fresh water is water that contains no more than 0.1% salt. It can be in the form of liquid, vapor or ice. Of the total amount of water resources is 2.5-3%. But of these 3%, only 1% is available to a person.
Its distribution to the globe characterized by unevenness. Europe and Asia, inhabited by 70% of the population, has only 39% at its disposal.
The main sources are:
- surface (rivers, streams, fresh lakes, glaciers);
- groundwater (springs and artesian springs);
- precipitation (snow and rain).
The largest reserve is stored in glaciers (85-90%), especially in the Antarctic. Russia ranks second in the world in terms of fresh water reserves (the first place belongs to Brazil). The main amount of water is concentrated in Lake Baikal: 80% of Russian reserves and 20% of world reserves.
The total volume of the lake is 23.6 thousand cubic kilometers. Every year it produces about 60 m 3 of water, characterized by extraordinary purity and transparency.
The problem of lack of fresh water
IN Lately humanity faces the problem of scarcity. Now more than 1.2 billion people are experiencing a permanent deficit. According to forecasts, in a few decades more than 4 billion people will find themselves in such conditions, since its number will decrease by half. Reasons for this situation include:
- pollution of water sources;
- population growth;
- melting glaciers due to the greenhouse effect.
This deficit is trying to be restored in the following ways:
- export;
- creation of artificial reservoirs;
- cost savings;
- artificial production of fresh water.
Methods for obtaining fresh water:
- desalination of sea waters;
- condensation of water vapor from the air in natural cold stores, most often in coastal caves.
With the help of condensation, huge reserves of water are formed, which fall under the seabed, where they often make their way through fresh springs.
Significance and application
First of all, water is essential for the Earth's ecosystems to function properly. Water creates and maintains life on Earth, plays the role of a universal solvent, takes part in all chemical reactions occurring in the human body, shapes the climate and weather.
Part human body contains 70% water. Therefore, it must be constantly replenished: without it, a person cannot live more than 3 days.
The main part of water resources is used agriculture and industry, and only a small part (about 10%) goes to consumer needs.
Recently, consumption for household needs has increased dramatically due to the introduction of automatic dishwashers and washing machines.
Composition
The water of rivers and lakes is not the same in composition. Since it is a universal solvent, its composition depends on the composition of the surrounding soil and the minerals found in it. It contains dissolved gases (mainly oxygen, nitrogen and carbon dioxide), various cations and anions, organic substances, suspended particles, microorganisms.
Characteristics
An important characteristic is its purity. The quality of water depends on the acidity pH, hardness and organoleptics.
The acidity of water is affected by the content of hydrogen ions, and the hardness is affected by the presence of calcium and magnesium ions.
Rigidity can be general, carbonate and non-carbonate, removable and irremovable.
The organoleptic quality of water depends on its smell, taste, color and turbidity.
The smell can be earthy, chlorine, oily, etc. It is evaluated on a 5-point scale:
- complete absence of smell;
- the smell is almost not felt;
- the smell can be noticed only if you specifically pay attention to it;
- the smell can be easily noticed and you don’t really want to drink it;
- the smell is distinctly audible, which refrains from wanting to drink it;
- the smell is particularly strong, making it undrinkable.
The taste of fresh water is salty, sour, sweet and bitter. It is also evaluated on a 5-point scale. It can be absent, very weak, weak, noticeable, distinct and very strong.
Color and turbidity are evaluated on a 14-point scale by comparison with the standard.
Water is characterized by inexhaustibility and self-purification. Inexhaustibility is determined by its self-replenishment, which leads to the natural cycle of water.
What determines the quality of water?
To study its properties, qualitative and quantitative analysis. Based on it, the maximum allowable concentration for each substance included in its composition is determined. But for some substances, viruses and bacteria, the maximum allowable concentration should be zero: they should be completely absent.
Quality is affected by:
- climate (especially the frequency and amount of precipitation);
- geological feature of the area (mainly the structure of the riverbed);
- environmental conditions of the region.
Special devices are used for cleaning. But even with the use of the most recent treatment systems, some pollutants (about 10%) remain in the water.
Fresh water classification
Subdivided into:
- ordinary;
- mineral.
Depending on the mineral content mineral water classified into:
In addition, there are also artificial fresh waters, which are divided into:
- mineral and distilled;
- desalinated and thawed;
- shungite and silver;
- "live" and "dead".
Melt water has a number of useful properties. But it is not recommended to cook it by melting snow or ice from the street: it will contain benzapyrene, which belongs to organic carcinogenic compounds, which are characterized by the first hazard class. Its source is car exhaust gases.
Shungite water is formed when water passes through shungite deposits ( rock), acquiring medicinal properties. They also make artificial shungite water, but its effectiveness has not been proven.
Silver water is formed as a result of saturation with silver. It has bactericidal properties and is able to kill pathogenic microorganisms.
"Living" and "dead" water exists not only in fairy tales. It is obtained by electrolysis of ordinary water and is used to treat various diseases.
- A leaking faucet, from which tap water flows in a thin stream, will carry away 840 liters per day.
- most clean water Finland boasts.
- most expensive water sell in Finland: 1 liter costs 90 dollars.
- If you put hot and cold water hot will freeze faster.
- Hot water will extinguish a fire faster than cold water.
- At school, we taught that water can be in 3 states. Scientists distinguish 14 states of frozen water and 5 - liquid.
- Modern people need 80-100 liters of water per day. During the Middle Ages, a person needed 5 liters.
- A person drinks 2-2.5 liters per day, and 35 tons in a lifetime.
Water scarcity is making itself known to humanity more and more. Something must be done to change the situation, otherwise the inhabitants of the blue planet, most of which is occupied by water, will be left without drinking. In this case, all living things will have only 3 days of life.
Water is the most common substance on our planet: although in different quantities, it is available everywhere, and plays a vital role in environment, and living organisms. Fresh water is of the greatest importance, without which human existence is impossible, and it cannot be replaced by anything. People have always consumed fresh water and used it for a variety of purposes, including domestic, agricultural, industrial and recreational uses.
Water reserves on Earth
Water exists in three states of aggregation: liquid, solid and gaseous. It forms the oceans, seas, lakes, rivers and underground waters that are in top layer bark, and soil cover Earth. In the solid state, it exists in the form of snow and ice in polar and mountainous regions. A certain amount of water is contained in the air in the form of water vapor. Huge volumes of water are found in various minerals in the earth's crust.
Reveal exact amount The world's water reserves are quite difficult, because water is dynamic and in constant motion, changing its state from liquid to solid to gaseous, and vice versa. As a rule, the total amount of water resources of the world is estimated as the totality of all waters of the hydrosphere. This is all free water that exists in all three states of aggregation in the atmosphere, on the surface of the Earth and in earth's crust up to a depth of 2000 meters.
Current estimates have shown that our planet contains a huge amount of water - about 1386,000,000 cubic kilometers (1.386 billion km³). However, 97.5% of this volume is salt water and only 2.5% is fresh water. Most of the fresh water (68.7%) is in the form of ice and permanent snow cover in the Antarctic, Arctic, and mountain regions. Further, 29.9% exists as groundwater, and only 0.26% of the total fresh water on Earth is concentrated in lakes, reservoirs and river systems, where it is most readily available for our economic needs.
These indicators were calculated over a long period of time, however, if shorter periods (one year, several seasons or months) are taken into account, the amount of water in the hydrosphere may change. It has to do with the exchange of water between the oceans, land and atmosphere. This exchange is generally referred to as the , or global hydrological cycle.
Fresh water resources
Fresh water contains a minimum amount of salts (no more than 0.1%) and is suitable for human needs. However, not all resources are available to people, and even those that are available are not always usable. Consider fresh water sources:
- Glaciers and snow covers occupy about 1/10 of the world's land and contain about 70% of fresh water. Unfortunately, most of these resources are located far from settlements and therefore is difficult to access.
- Groundwater is by far the most common and accessible source of fresh water.
- Freshwater lakes are mainly located at high altitudes. Canada contains about 50% of the world's freshwater lakes. Many lakes, especially those located in arid regions, become salty due to evaporation. The Caspian Sea, the Dead Sea, and the Great Salt Lake are among the world's largest salt lakes.
- The rivers form a hydrological mosaic. There are 263 international river basins on Earth, which cover more than 45% of the land of our planet (the exception is Antarctica).
Water resources objects
The main objects of water resources are:
- oceans and seas;
- lakes, ponds and reservoirs;
- swamps;
- rivers, canals and streams;
- soil moisture;
- underground waters (soil, ground, interstratal, artesian, mineral);
- ice caps and glaciers;
- atmospheric precipitation (rain, snow, dew, hail, etc.).
Problems in the use of water resources
For many hundreds of years, human impact on water resources was insignificant and was of an exclusively local nature. The excellent properties of water - its renewal due to the cycle and the ability to purify - make fresh water relatively purified and with quantitative and qualitative characteristics that will remain unchanged for a long time.
However, these features of water gave rise to the illusion of the immutability and inexhaustibility of these resources. Out of these prejudices, a tradition has arisen of the careless use of vital water resources.
The situation has changed a lot in recent decades. In many parts of the world, the results of long-term and wrong actions towards such a valuable resource have been discovered. This applies to both direct and indirect use of water.
Throughout the world, for 25-30 years, there has been a massive anthropogenic change in the hydrological cycle of rivers and lakes, affecting the quality of water and their potential as a natural resource.
The volume of water resources, their spatial and temporal distribution, are determined not only by natural climate fluctuations, as before, but now also by the types of economic activities of people. Many parts of the world's water resources are becoming so depleted and heavily polluted that they can no longer meet ever-increasing demands. It may
be the main factor hindering economic development and population growth.
Water pollution
The main causes of water pollution are:
- Wastewater;
Household, industrial and agricultural wastewater lead to pollution of many rivers and lakes.
- Waste disposal in the seas and oceans;
The dumping of garbage in the seas and oceans can cause huge problems, because it negatively affects the living organisms that live in the waters.
- Industry;
Industry is a huge source of water pollution, which produces substances that are harmful to people and the environment.
- radioactive substances;
Radioactive pollution, in which there is a high concentration of radiation in the water, is the most dangerous pollution and can spread into ocean waters.
- Oil spill;
An oil spill poses a threat not only to water resources, but also to human settlements located near a contaminated source, as well as to all biological resources for whom water is a habitat or a vital necessity.
- Leaks of oil and oil products from underground storage facilities;
A large amount of oil and oil products are stored in tanks made of steel, which corrodes over time, which creates leaks. harmful substances into the surrounding soil and groundwater.
- Precipitation;
Precipitation, such as acid precipitation, is formed when air is polluted and changes the acidity of water.
- Global warming;
An increase in water temperature causes the death of many living organisms and destroys a large number of habitats.
- Eutrophication.
Eutrophication is the process of reducing the quality characteristics of water associated with excessive enrichment with nutrients.
Rational use and protection of water resources
Water resources provide rational use and security, ranging from individuals to businesses and governments. There are many ways we can reduce our impact on the aquatic environment. Here are some of them:
Water saving
Factors such as climate change, population growth and increasing aridity are increasing pressure on our water resources. the best way save water is to reduce consumption and avoid the growth of wastewater.
On the household level, there are many ways to save water, such as: shorter showers, installing water-saving appliances, washing machines with low water consumption. Another approach is to plant gardens that do not require much water.