MUNICIPAL KAZZEN EDUCATIONAL INSTITUTION
Kyiv BASIC EDUCATIONAL SCHOOL
"POLLUTION AND PROTECTION OF THE HYDROSPHERE"
Methodical development
Geography teacher
Topic: Pollution and protection of the HYDROSPHERE
Class: 6
Lesson type: combined, designing a mode of action on the Federal State Educational Standard.
Planned results: identify sources of pollution of the hydrosphere, as well as measures to protect the hydrosphere, work in pairs, express your point of view, create a collective mini-project.
Subject learning outcomes: know the geographical nomenclature on the topic of hydrosphere objects, geographical objects.
Meta-subject learning outcomes: the ability to organize their activities, determine the objectives of the lesson, the ability to work in a team, express their opinions, draw conclusions.
Universal learning activities:
Personal: identifying cause-and-effect relationships, making judgments.
Regulatory: evaluate the work of classmates, work in accordance with the set goals, compare the results obtained with the expected ones.
Communicative: the ability to communicate and interact with each other.
Cognitive: manifestation of the educational and cognitive process to geographical science.
The purpose of the lesson:
To expand and deepen knowledge about the significance and pollution of the hydrosphere, as well as to identify the consequences of pollution of the hydrosphere and measures to protect the Earth's water shell.
Tasks:
Educational:
1. Reveal the relationship between water and people.
2. Show the consequences of human impact on the hydrosphere.
3. Create conditions for the skills of project activities.
Educational:
1. To get acquainted with the sources of pollution of the hydrosphere, to identify ways to solve the sources of pollution of the hydrosphere.
Developing:
1. Contribute to the formation and development of the ecological qualities of the individual.
2. Development of students' interest in the global problems of our time.
Lesson plan:
1. Organizational moment.
2. Work on the material covered.
3 Formulation of the topic and purpose of the lesson.
4. Significance of the hydrosphere.
5. Physical education.
6. Work on the project.
Purpose: to identify the causes of pollution of the hydrosphere and measures to protect the water shell of the Earth.
Project stages:
Identification of the main sources of pollution of the hydrosphere;
Security measures;
Creation of guide posters;
7. The result of the lesson.
8. Reflection.
9. Homework.
DURING THE CLASSES
1. Organizational moment.
Greetings. Organization for the lesson.
2. Work on the material covered.
--- We have come to the final topic of a large section called ………. children's answers(hydrosphere).
To test the assimilation of the material covered, I suggest you play the game "Geographic Lotto".
Played game
ATTACHMENT 1.
3 Formulation of the topic and purpose of the lesson.
--- Listen to the poem:
Water is God's source
Water is sunshine!
We ask water questions
We get the answer with water.
We cleanse the body with water,
Our soul splashes in the water.
When you talk to water
That must be whispered slowly.
We wash the child with water,
To wash away trouble.
Water is a wonder of nature
And we can't live without water.
Water is the property of the people!
We must cherish water!
Guys, based on the poem you listened to, say what will be discussed today in the lesson ...... ... ... ... children's answers(on the meaning of water)
--- Listen to another poem:
The river flowed along the outskirts.
Quiet.
But we loved her
After all, she was the first for us,
And that means the best in the world.
Now it's full of rubbish
And rust and green slime,
And the marsh horsetail came out.
It's like people have a goal
Kill - her
And they got their way.
What else will we talk about today in the lesson ...... children's answers(on water pollution)
Let's formulate the topic of the lesson ...... children's answers(value and contamination of hydra)
Now let's formulate the purpose of our lesson .... children's answers
4. Significance of the hydrosphere.
--- Water - priceless gift nature.
Water is one of the main resources on earth.
Life without water is impossible!
Water spreads all over the Earth in huge oceans and small puddles.
Water is part of all living organisms. We ourselves are more than half made up of water.
Water is more precious than gold, argued the Bedouins, who wandered in the sands all their lives. They knew that no amount of wealth would save a traveler in the desert if the supply of water ran out.
Guys, what else is the meaning of water……… children's answers.
In the water we wash, swim, sled, skate, ski. We drink. Necessary for plants, animals, birds.
A person can live without water for only a few days.
That's what water is!
Water is used for economic sectors, as transport routes, for recreation, and fishing.
- household waste
- oil
- deforestation along water bodies
Guys, what can pollution of the hydrosphere lead to?
………children's answers
1. death of living beings
2. depletion of fresh water
3. diseases.
4. drying up of rivers and lakes.
Group 2: Protection measures.
- do not wash cars on the banks of water bodies
- do not litter the banks with garbage
- do not throw garbage into water bodies
3rd group: Creation of a guide poster.
7. The result of the lesson.
--- Compiling a memo:
REMINDER
1. Do not pollute rivers and lakes!
2. Take care of drinking water!
3. Purify industrial and domestic water!
4. Follow the rules for transporting goods!
5. Observe the rules of recreation on the coast of water bodies!
6. Follow the rules for catching fish!
And I want to end the lesson with these words:
Let the rivers not die on Earth
Let them bypass their trouble
Let it remain clean in them forever
Cold and clear water!
8. Reflection.
Were you interested in today's lesson?
Did you learn anything important that you need in the lesson?
Do you think that the problem of water protection is so important for a person?
What water conservation measures can the residents of our village take to keep the water clean?
I suggest that you fill out a self-control sheet.
Self-control sheet:
F.I.______________
Try to define your own knowledge and skills as follows:
Put a + sign in one of the statements
1. “I understood everything, I can explain this material to another”
2. “I understood the material, I can explain it to another, but with some help from the teacher”
3. "I understood the material partially"
4. "I didn't understand anything"
Try to objectively evaluate your work and rate yourself:
I put myself _______
Teacher evaluation _____
9. Homework.
Fill in the table "Guide"
Application
"Geographic Lotto"
Questions for students:
1. The part of the ocean, sea or lake that protrudes into the land.
2. The beginning of the river.
3. A river that flows into another river.
4. Artificial reservoir.
5. The greatest sea-lake.
6. Great river of Russia.
8. The place where the river flows into the sea.
9. The largest ocean.
11. The deepest lake in the world.
13. The smallest ocean.
14. A group of nearby islands.
Rules of the game:
Students take turns answering the question and closing the box.
Resources Used
Resources Used
nsportal. ru/shkola/geografiya... copy
mirgeografii. ru/zagryaznenie... copy
do. gendocs. ru/docs/index-10370.html copy
knowledge. allbest. ru/ecology... copy
Protection of the hydrosphere
Water resources.
Water, occupying 71% of the Earth's surface, is the most abundant and valuable resource. The world's water reserves are huge - about 1389 million km 3 . If they were distributed equally, then each inhabitant of the planet would have 280 billion liters. However, 97% of water resources are in the oceans and seas, in which the water is too salty. The remaining 3% is fresh water. They are distributed as follows:
Polar ice and glaciers
Water makes up between 50-97% of the weight of all plants and animals and about 70% of the weight of the human body.
Of all fresh water, humanity can use only 0.003%, because. it is either highly polluted, or lies at great depths and cannot be extracted at reasonable prices, or is contained in icebergs, polar ice, in the atmosphere and in the soil.
Water is in constant circulation, Fig. 1. This natural process of recycling occurs until water consumption becomes more intense than its reserves are replenished and until the volume of waste is exceeded, making water unusable. There are two sources of fresh water: surface water and groundwater.
Rice. 1. Water cycle in the biosphere.
Surface water is fresh water flowing from certain territory to streams, lakes, swamps and reservoirs. The area from which surface water flows into the main river and its tributaries, with which sediment and pollutants can enter, is called a spillway, or spillway basin. But only part of the annual flow can be used.
Part of the runoff has such a speed that it is impossible to delay it, and the other part must be left in the rivers to maintain life in them. In dry years, the total volume of runoff is significantly reduced.
Ground water. Part of the atmospheric precipitation seeps into the ground and accumulates there in the form of soil water, filling the pores of the soil and soil. Ultimately, most of the soil moisture evaporates and is released back into the atmosphere.
Part of the water under the influence of gravity moves deeper and fills the pores and cracks in the layers of sand, gravel and sandstone. The zone in which all the pores are filled with water is called the saturation zone. Permeable, water-saturated deposits are called aquifers, and the water they contain is called groundwater. If the rate of withdrawal of water from the aquifer exceeds the rate of its accumulation, groundwater will change from a slowly renewable to a non-renewable resource within a human lifetime.
Groundwater can be non-pressure and pressure. Free-flow groundwater is above a layer of impermeable rock or clay. Wells and wells are used to collect non-pressure groundwater, and water is extracted by pumps.
Pressurized groundwater is formed between two water-resistant layers (eg clay) and is under overpressure. When opened by wells, water can pour itself to the surface. Such wells are called artesian. In other wells, the pressure is lower and water must be pumped out.
Water use. The criteria for water use are indicators of water intake and water consumption. Almost three-quarters of the water produced in the world is used for irrigation, the rest is used in industry and utilities, for cooling equipment at power plants, etc.
Growing one ton of wheat requires 1,500 tons of water, one ton of rice - more than 7,000 tons, one ton of cotton - 10,000 tons.
A huge amount of water is required for food production and various industrial products. Before a liter can of fruits or vegetables appears in the store, 40 liters of water will be spent on it. For the production of the daily norm food products one person needs about 6 m 3 water.
Water resource issues
Water shortage. The problem of providing the population with a sufficient amount of fresh water is relevant for many parts of the world. Every year about 25 million people suffer from drought, of which about 20 thousand die. Severe droughts leading to famine and disease occur periodically in 80 countries, most of Asia and Africa, which are home to 40% of the world's population. Almost 150 of the 214 largest rivers in the world are used by two or more countries. In these states, disputes and conflicts arise over the use of water.
Excess water. Too much rain leads to floods. In India, for example, 90% of the precipitation falls from June to September. In the 1980s, about 15 million people were affected by severe floods. About 5,000 people died annually, and material damage amounted to several tens of billions of dollars. Floods and droughts are considered natural disasters. However, since the 1960s, human activities have been the cause of the sharp increase in the number of deaths during floods. The destruction of vegetation and soils that retain moisture, the construction of roads and other structures contributes to the rapid runoff of rainwater.
Contaminated drinking water. In 1983, the World Health Organization (WHO) estimated that 61% of the rural and 26% of the urban population in developing countries, i.e. 1.5 billion people use dirty water. Every year about 5 million people die from cholera, dysentery and other water-borne diseases (an average of 13,700 per day).
The main sources of water pollution. Of the total volume of water taken, only 1/4 is used irrevocably, 3/4 of the water is returned with wastewater. Even after treatment, wastewater must be diluted with clean water. Worldwide, 5,500 km are spent on waste disposal 3 pure water, i.e. 30% of the planet's runoff. The main sources of water pollution are shown in Fig. 2
Pollution can be divided into several groups. According to the physical state - insoluble, colloidal and soluble. In composition - mineral, organic, bacterial and biological.
Minerals are represented by sand, clay, mineral salts, solutions of acids, alkalis, etc.
Organic - can be of plant, animal origin, and also contain oil and products derived from it, synthetic surfactants (surfactants).
Bacterial and biological pollution - effluents from food and light industry enterprises, household effluents (drainage from toilets, kitchens, showers, laundries, canteens, etc.). At many industrial enterprises, water is used as a coolant, solvent, is part of the product, is used for washing, enrichment, cleaning of raw materials and products.
In addition, synthetic surfactants (surfactants) are used in many technological processes. Currently, it is one of the most common chemical pollutants that is difficult to control. Surfactants can have a negative impact on water quality, the self-cleaning ability of water bodies, the human body, as well as enhance the adverse effects of other substances.
An important source of pollution are pesticides, which enter the reservoirs with rain and melt water from the soil surface. During aerial treatment of fields, the preparations are carried away by air currents and deposited on the surface of the reservoir.
The oil industry is a significant source of pollution of water bodies with oil and oil products. The ingress of oil into water bodies occurs when oil products spilled on the surface of the earth are washed away by rain and melt water, when oil pipelines break through, with wastewater from enterprises, etc.
Acid rain is a major hazard to water bodies.
The influence of oil on the reservoir.
Poorly treated oily effluents contribute to the formation of an oil film on the surface of the reservoir, 0.4-1 mm thick.
One ton of oil can cover from 150 to 210 hectares of a reservoir. In the presence of an oil film, the amount of oxygen dissolved in water drops sharply, because the oxygen contained in the water is spent on the oxidation of petroleum products, and the new portion does not dissolve.
Decrease O 2 dramatically affects the life of organisms and fish. Respiratory depression in fish is observed when the content of O 2 4.5 mg/l, and some even at 6-7.5 mg/l.
From the oil film from the surface of the reservoir, light fractions evaporate, water-soluble fractions dissolve in water, and heavy fractions adhere to solid particles suspended in water and settle to the bottom and accumulate there.
The heavy residues that have sunk to the bottom continue to oppress the life of the reservoir: some of them decompose at the bottom, polluting the water with soluble decay products, and some are again brought to the surface with gases released from the bottom. Each bottom gas bubble bursts on the surface of the water, forming an oil slick.
The formation of bottom sediment leads to its poisoning of zoo- and phytoplankton, which serves as food for fish.
Oil and oil products give the water an oily smell and taste, as a result of which the water of the reservoir becomes unsuitable for water supply.
In the presence of 0.2-0.4 mg/l of oil in water, the water acquires an oil smell, which is not eliminated even when filtered and chlorinated. The smell of oil travels farther than any other pollution.
For fish, the most toxic light fractions of oil, especially aromatic hydrocarbons. They are able to accumulate in the tissues of fish and, when they enter the human body, cause the formation of a carcinogenic-protein complex in fat cells. Fry hatched from eggs of polluted fish have mutogenic disorders (lack of gills, two heads, etc.)
Impact on water bodies of acid rain
Rain water has a neutral reaction (PH=7). But since even the cleanest air contains carbon dioxide, dissolving it, water acquires a pH of 5.6 - 5.7. Washing out acidic components, in particular nitrogen and sulfur oxides, from the polluted atmosphere, the rain becomes acidic.
In a fresh water body, water often has not a neutral, but an alkaline reaction (РН=8) due to the minerals washed out of the soil and the decomposition of organic residues. All the inhabitants of rivers and lakes have adapted to this composition.
When acid rains fall, the pH of which can reach 2 - 3, the water retains an alkaline reaction for some time, due to the ability to neutralize the acid entering it. Gradually, the lake begins to acidify. At pH = 7, when water acquires a neutral reaction, the calcium content begins to fall in it. On spawning grounds, eggs die, which need a certain dose of calcium for the emergence of embryos. At pH = 6.6 snails die, at pH = 6 shrimps disappear, the eggs of other amphibians die, at pH = 5.5 species diversity Living creatures. As the bacteria that decompose the organic matter of the reservoir die, dead acidic and other acids begin to accumulate. organic remains, Plankton, which is the basis of food for the ichthyofauna, is dying. Disturbed calcium balance in some fish disrupts the transfer of ions to the gill membranes, in others it leads to a loss of the ability to form eggs. Toxic metals (aluminum, mercury, lead, cadmium, beryllium, nickel) begin to leach from bottom sediments and surrounding soils. Often they are more dangerous than the high acidity itself. At pH = 5.5, acid mosses and fungi develop rapidly. When the pH reaches 4.5, there are no more fish left in the reservoir, amphibians and many insects die. The water in the lake looks clean and transparent, because all microorganisms have died out in it and organic remains lie untouched on the bottom. Sphagnum, some algae and fungi form a dense carpet that prevents the entry nutrients. Under this carpet, oxygen reserves gradually dry up and bacteria begin to develop - anaerobes that emit carbon dioxide, methane and hydrogen sulfide.
Rationing of pollution in water bodies
The basis for the regulation of water quality in water bodies is taken as a set of permissible values of indicators of the composition and properties of water (MAC harmful substances in a water body), which maintain safety for human health and normal conditions for water use.
The rationing is based on three criteria of harmfulness: Drowning out the rest of the vegetation.
a) impact on the general sanitary regime of the water body,
b) influence on the organoleptic properties of water,
c) impact on public health.
The impact on the general sanitary regime is assessed by the ability of the reservoir to self-purify; intensity of mineralization processes of nitrogen-containing compounds; intensity of development and death of algae.
Organoleptic properties (color, smell, taste) are easily detected by the human senses and drastically reduce the use of the source. They are not removed by conventional cleaning methods.
The impact of pollution on health is established by long-term experiments on animals.
After studying all the criteria, MPC is set according to the most significant (limiting) indicator of harmfulness.
Quality standards for surface waters are established for drinking, household and fishery use.
Household and drinking include the use of water bodies for domestic purposes and food industry enterprises.
Municipal water use - the use of water bodies for swimming, sports and recreation of the population.
Fishery streams and reservoirs are used for reproduction, fishing and migration of fish, invertebrates and aquatic mammals.
As a rule, the reservoir is polluted by several ingredients. Therefore, the combined impact of pollution is assessed. In this case, the sum of the ratios of pollutant concentrations (C i ) to their MPC should be less than or equal to one.
Fishery MPCs are based on complex ichthyological, hydrobiological, microbiological and chemical studies.
The fishery MPC is such a concentration of harmful substances, with the constant presence of which the reservoir remains practically clean: 1- there are no cases of death of fish and their food organisms; 2- there is no permanent disappearance of certain fish species; 3 - there is no damage to the commercial quality of the fish; 4 - there are no conditions in the reservoir that can lead to the death of fish in certain seasons.
When developing fishery MPCs, a comprehensive study is carried out, in laboratory and field conditions, on fish and on fodder invertebrates.
According to their relative sensitivity to pollution, fish are conditionally divided into three groups:
highly sensitive (salmon, whitefish, sturgeon, zander);
medium sensitivity (perch, smelt, pike);
insensitive and not suitable for toxicological studies (carp, crucian carp, guppies).
The main indicators are: survival, reproduction, growth rates, unpleasant taste and smell, accumulation of toxicants and pathogens.
Water quality indicators
The main indicators of water from various sources are: physical, chemical, biological and bacteriological
Physical indicators are characterized as general sanitary. These include:
Chromaticity (coloration) is estimated in conventional units;
Taste and smell are determined by dissolved salts, gases, organic compounds and are evaluated in points (organoleptic), or according to the dilution threshold.
Chemical indicators are conditionally divided into five groups: main ions, dissolved gases, biogenic substances, microelements, organic substances.
Major ions - HCO anions are the most common in natural waters- 3, SO 2- 4, Cl -, CO 2- 3, HSiO - 3 and cations Na +, K +, Ca 2+, Mg 2+, Fe 2+ , they make up 90-95% of the total content.
Dissolved gases: O 2 , CO 2 , H 2 S and others. The oxygen content in water is determined by its intake from the air and formation as a result of photosynthesis. The solubility of oxygen depends on the temperature of the water. In winter it is less. SO 2 It is found both in dissolved form and in the form of carbon dioxide. The main sources of CO 2 are biochemical processes of decomposition of biochemical substances. H 2 S can be of organic (decay product) and inorganic (dissolution of mineral salts) origins. H 2 S gives the water an unpleasant odor and corrodes the metal.
biogenic substances. This group includes nitrogen and phosphorus compounds necessary for the life of aquatic organisms and formed in the process of metabolism.
Trace elements - elements whose content in water is less than 1 mg / l. The most important are iodine and fluorine.
Organic substances are present in the form of humic compounds formed during the decomposition of plant residues and organic compounds coming from the runoff. They are defined by indicators. COD (chemical oxygen demand) and BOD (biological oxygen demand). COD is the amount of oxygen that goes to the oxidation of organic matter by chemical means in the presence of a catalyst (silver sulfate or potassium bichromate), mg/l. BOD is the amount of oxygen that goes to the oxidation of organic matter naturally(biological oxidation of substances), mg/l.
Active pH reaction. pH is the negative logarithm of the concentration of hydrogen ions in a solution.
Biological indicators of water quality are hydrobionts and hydroflora.
Hydrobionts - inhabitants from the bottom to the surface.
Hydroflora - macro- and microphyte vegetation. Macrophytes are the highest form of vegetation. Microphytes are algae. With the death of macrophytes, water is enriched with organic substances that worsen organoleptic characteristics. Microphytes - produce oxygen.
Bacteriological indicators - the presence of pathogens (E. coli). The content of bacteria of the Escherichia coli group in 1 liter of water determines its coli index. the smallest volume of water (ml) per 1 E. coli is called the coli titer.
Requirements for water quality depend on the purpose of its use. In table. given the requirements for the quality of drinking water.
Less stringent requirements are imposed on water used for industrial purposes. Moreover, they proceed from the technology (for boilers - soft, etc.).
All reservoirs, depending on the purpose of water use, are divided into household and drinking, household and fishery purposes (table).
Indicators
Conditions for the discharge of wastewater into water bodies
The conditions for the discharge of wastewater into water bodies are regulated by the "Rules for the Protection of Surface Water from Wastewater Pollution". These rules include the main provisions for the protection of surface waters from pollution, water quality standards for water bodies used for drinking, domestic and fishery purposes; technical conditions for the discharge of wastewater into water bodies, the procedure for coordination and control. The rules apply to projects under construction, reconstruction, expansion and operating enterprises.
When determining the conditions for the discharge of wastewater into a reservoir, the following possibilities are primarily considered:
Improvement of production technology aimed at reducing water consumption and wastewater discharge into the reservoir (up to its elimination); the use of wastewater in circulating water supply systems, as well as reducing the degree of pollution of wastewater.
The use of treated and neutralized urban wastewater in the process water supply of enterprises.
The use of wastewater from this enterprise for technical water supply to other enterprises.
Joint treatment and disposal of wastewater from this enterprise with wastewater from other enterprises and with municipal wastewater.
Self-cleaning and disposal of wastewater.
Discharge of sewage is not allowed
When placing an enterprise on a low-power reservoir, when the possibility of diluting wastewater in it and its self-purification is limited.
In the presence of highly toxic substances in wastewater, the MPCs of which in the reservoir are extremely low.
When other objects are located on the reservoir that create a high level of pollution in the reservoir.
An indicator of the safe value of discharged effluents is the maximum allowable discharge (MPD). It is calculated:
PDS=q . C PDS, g/h,
where q is the maximum wastewater flow, m 3 /hour;
With pds - permissible concentration of pollutants in the descent, g/m 3 . With pds = n. (C MPC - C f ) + C f ,
where C f – background concentration of pollutants in the watercourse.
Cleaning of drains
Wastewater from industrial enterprises is divided into:
- household and fecal (from sanitary facilities, showers, toilets, canteens, etc.),
– storm water (from washing floors, rain, snow, water from industrial sites)
- production (from technological processes), which, in turn, are divided into conditionally clean (from refrigerators, heat exchangers, etc.) and contaminated.
drains different types, as a rule, are discharged into their sewer system. All drains, with the exception of conditionally clean, must be treated before being used or discharged.
Conditionally pure water should be sent for cooling or heating and returned to the circulation cycle.
The main methods of wastewater treatment are shown in fig.
Wastewater treatment methods are divided into mechanical, physico-chemical, electro-chemical, biochemical.
mechanical cleaning.
Straining. To extract large impurities, to avoid clogging of pipes and channels, gratings are used.
To remove smaller suspended particles, sieves are used, the openings of which depend on the trapped impurities (0.5-1 mm).
To remove coarse impurities, settling in sand traps, settling tanks, oil traps, clarifiers, etc. is used.
Sand traps are designed to remove mechanical impurities larger than 250 microns (sand, scale). The principle of operation of the sand trap is based on a change in the speed of movement of solid heavy particles in a fluid stream. Sand traps can be of various designs (with horizontal, vertical or circular movement of water).
The diameter of the removed particles is 0.2-0.25 mm, the duration of the flow of water is not more than 30 seconds, the depth of the sand traps is 0.25-1 m, the width is determined by calculation.
Oil traps. Are applied to allocation from waste waters of oil products, oils and fats. The principle of operation is based on the floating of particles with a density lower than water (Fig.).
The speed of water movement in the oil trap is from 0.005-0.01 m/s, while 96-98% of oil floats. The floating rate of particles depends on their size, density and viscosity of the solution. Particles of 80-100 microns float up. Settling time is about 2 hours. The depth of the oil trap is 1.5-4 m, the width is 3-6 m, the length is about 12 m, the number of sections is at least two, connected in series.
Filtration. It is used to isolate finely dispersed solid and liquid particles from wastewater that do not settle (Fig.). As filter materials, metal meshes, fabric filters (cotton, glass and artificial fibers), ceramic filters are used, sometimes granular materials (sand, gravel, peat, coal, etc.) are used. This is, as a rule, a reservoir, in the lower part of which a drainage is arranged to drain purified water. Filtration speed 0.1-0.3 m/hour. The filters are cleaned by blowing with air or by washing.
Hydrocyclones purify wastewater of suspended particles under the action of centrifugal force (Fig.). Water is tangentially fed into the hydrocyclone at high speed. When the liquid rotates in it, centrifugal forces act on the particles, throwing heavy particles to the periphery of the flow. The greater the density difference, the better the separation.
Physical and chemical methods cleaning.
Flotation is used to remove insoluble dispersed impurities from wastewater, which are poorly settled. To do this, pressurized air is supplied to the water through perforated pipes with small holes. When moving through a layer of liquid, air bubbles merge with particles of pollution and raise them to the surface of the water, where they collect in the form of foam. The cleaning effect depends on the size of the air bubbles, which should have a size of 10-15 microns. The degree of purification is 95-98%. To increase the degree of purification, coagulants can be added to the water. Sometimes oxidation is also carried out in the flotator, then the water is saturated with air enriched with oxygen or ozone. In other cases, to eliminate oxidation, flotation is carried out with inert gases. Flotation can be pressure and vacuum.
Adsorption treatment (purification on solid sorbents) is used for deep purification of wastewater with a low concentration of pollutants, if they are not biologically decomposed or are strong poisons (phenols, herbicides, pesticides, aromatic and nitro compounds, surfactants, dyes, etc.).
Adsorption can be reactive, i.e. with the extraction of the substance from the adsorbent and destructive, with the destruction of the extracted substance together with the adsorbent. The cleaning efficiency, depending on the adsorbent used, is 80-95%. Activated carbon, ash, slags, synthetic sorbents, clays, silica gels, aluminum gels, metal oxide hydrates are used as adsorbents. The most versatile activated carbons with a pore radius of 0.8-5 nm. The adsorption process is carried out either with intensive mixing of the adsorbent and water, followed by settling, or filtration through the adsorbent bed. The spent adsorbent is regenerated with superheated steam or heated inert gas.
Ion-exchange treatment is used to extract metals (Zn, Cu, Cr, Ni, Pb, Hg, Cl, Va, Mn, etc.) from wastewater, as well as arsenic, phosphorus, cyanide compounds and radioactive substances. The method allows recovering valuable substances. The essence of the method is that there are natural and synthetic substances (ion exchangers) that are insoluble in water, which, when mixed with water, exchange their ions for ions contained in water. Ion exchangers capable of absorbing positive ions from water are called cation exchangers, and negative ions are called anion exchangers. Ion exchangers that exchange both cations and anions are called amphoteric. Inorganic natural ion exchangers include zeolites, clay minerals, feldspars, various micas. Silica gels, sparingly soluble oxides and hydroxides of some metals (aluminum, chromium, zirconium, etc.) belong to inorganic synthetic ones.
Organic natural ion exchangers are humic acids of soils and coals. Organic artificial ones include ion-exchange micas. Simplified, the formula of the cation exchanger can be written RH, and the anion exchanger - ROH, where R is a complex radical.
The ion exchange reaction proceeds as follows:
in contact with cation exchanger
RH+NaCl - RNa+HCl,
in contact with anion exchanger
RO H + NaCl - RCl + NaOH.
The processes of ion-exchange wastewater treatment are carried out on batch and continuous installations (Fig.).
Extraction is used to treat wastewater containing phenols, oils, organic acids, metal ions, etc. Extraction is beneficial if the cost of the extracted substances compensates for the costs of its implementation. At a concentration of 3-4 g/l, extraction is more beneficial than adsorption.
Extraction is carried out in 3 stages:
intensive mixing of waste water with an extractant (organic solvent). In this case, two liquid phases are formed; one phase - an extract containing extractable substances and an extractant, the other - a refined - waste water and an extractant;
separation of extract and raffinate;
regeneration of the extractant from the extract and raffinate.
The extractant is isolated from the extract by evaporation, distillation, chemical interaction and precipitation.
Ultrafiltration is the process of filtering solutions through semi-permeable membranes under pressure exceeding osmotic pressure. The membranes allow solvent molecules to pass through, retaining dissolved substances, size =
Chemical methods.
Chemical methods of wastewater treatment include neutralization, coagulation and flocculation, oxidation and reduction. Chemical treatment is carried out as post-treatment of water before biological treatment or after it.
Neutralization. Wastewater containing acids or alkalis is neutralized before being discharged into water bodies or before technological use. Waters with a pH of 6.5 ... 8.5 are considered practically neutral. Alkalis are used to neutralize acidic effluents, acids are used to neutralize alkaline effluents.
Neutralization can be carried out in various ways: mixing acidic and alkaline wastewater, adding reagents, filtering through neutralizing materials. To neutralize acidic waters, alkalis (NaOH, KOH), soda (Na 2CO3 ), ammonia water (NH 3 OH), calcium and magnesium carbonates (CaCO 3 and MgCO 3 ), dolomite (CaCO 3 and MgCO 3 ), cement. However, the cheapest reagent is milk of lime (Ca(OH) 2 ).
Magnesite, dolomite, limestone, slag, ash are used to neutralize alkaline wastewater, and exhaust gases containing CO are also used. 2, SO 2, NO 2, N 2 O 3 and others. At the same time, flue gases are cleaned from acidic components.
Coagulation is the process of enlargement of dispersed particles during their interaction and association into aggregates. In wastewater treatment, it is used to accelerate the process of settling fine impurities and emulated substances. Coagulants in water form flakes of metal oxide hydrates, which quickly settle under the action of gravity and trap colloidal and suspended particles.
Flocculation is the process of aggregation of suspended particles when highly molecular compounds, called flocculants, are added to wastewater. In contrast to coagulation, aggregation occurs not only as a result of contact, but also as a result of the interaction of the flocculant and the substance to be extracted. For purification, natural and synthetic (polyacrylamide, starch, cellulose) flocculants are used.
Purification by oxidation and reduction.
The following oxidizing agents are used for wastewater treatment: gaseous and liquefied chlorine, chlorine dioxide, bleach, calcium and sodium hypochlorites, potassium permanganate, potassium dichromate, hydrogen peroxide, air oxygen, ozone, etc.
When oxidized, toxic contaminants turn into less toxic ones with subsequent removal from the water. Cleaning by oxidation is associated with a high consumption of reagents, so oxidation is used when contaminants are difficult to remove by other methods.
Chlorine oxidation. Chlorine and substances containing active chlorine are the most common oxidizers. They are used to treat wastewater from hydrogen sulfide, phenols, cyanides and bacteria.
When disinfecting cyanide waters, they are oxidized to nitrogen and carbon dioxide.
When water is chlorinated, the bacteria in the water die as a result of the oxidation of substances that make up the cell protoplasm.
Air oxygen oxidation is used in water purification from iron, for the oxidation of ferrous iron to ferric iron and the subsequent separation of iron hydroxide
Recovery purification is used in cases where water contains easily recoverable substances (compounds of mercury, chromium, arsenic). At the same time, they are reduced to metals, and then removed by filtration or flotation.
Electrochemical cleaning methods. To purify water from various dissolved and dispersed impurities, anodic oxidation, cathodic reduction, electrocoagulation, electroflotation, and electrodiolysis are used. All these processes take place on the electrodes when a direct electric current is passed through the wastewater.
Biochemical cleaning methods.
Biochemical treatment methods are used to treat household and industrial wastewater from organic and some inorganic compounds (hydrogen sulfide, sulfides, ammonia, nitrates, etc.). The cleaning process is based on the fact that some microorganisms use contaminants in food. Biochemical oxidation is possible if the ratio (BOD P / COD) 100 >= 50%, wastewater does not contain toxic impurities of heavy metals, and the concentration of biologically non-oxidizable substances does not exceed certain values.
Known aerobic and anaerobic methods of biochemical treatment. The aerobic method uses microorganisms that require oxygen and a temperature of 20-40 0 C.
Anaerobic methods proceed without oxygen, they are used mainly for the disinfection of sediments.
Activated sludge consists of living organisms and a solid substrate. Living organisms are mainly represented by 12 types of microorganisms and protozoa (worms, stale fungi, yeasts, accumulations of bacteria, crustaceans, etc.). Chemical composition activated sludge can be written C m H n O k N c S i .
The biodegradability of wastewater is characterized through its BOD biochemical index P / COD. Domestic wastewater has an indicator> 0.5, industrial (0.05-0.3).
According to the biochemical indicator, wastewater is divided into four groups:
biochemical indicator> 0.2 - waters are well purified biochemically (food enterprises, petrochemistry);
biochemical indicator 0.1-0.02 - water after mechanical treatment can be directed to biochemical oxidation;
BP - 0.01-0.001 - wastewater can be sent for biochemical treatment after mechanical and local physical and chemical treatment.
BP
For successful biochemical oxidation, N, P, K, S, Mg, Ca, NaCl, Fe, Mn, Mo, Ni, Co, Zn, Cu must be present in wastewater.
Aerobic methods of biochemical purification.
Aerobic purification can take place in natural and artificial structures. Under natural conditions, cleaning occurs in irrigation fields, filtration fields and biological ponds. Biofilters, aerotanks and oxygen tanks are artificial.
The choice of facilities depends on climatic conditions, the volume and composition of effluents, and the concentration of pollutants.
In artificial structures, cleaning is faster than in natural conditions.
Irrigation fields. Wastewater is used for irrigation of agricultural crops, planting trees and shrubs.
Biological ponds represent a 3-5 step cascade of ponds through which pre-purified water moves at a low speed. Ponds come with natural and artificial aeration. With natural aeration, ponds have a small (0.5-1 m) depth and are inhabited by aquatic organisms. With artificial aeration, ponds are aerated by mechanical mixing or air blowing.
Biofilters are facilities in which wastewater is filtered through a feed material covered with a biological film formed by colonies of microorganisms. Biofilm microorganisms oxidize organic matter, using it as food and energy. The dead film is washed off with waste water and removed from the body of the biofilter. The air oxygen necessary for the biochemical process enters the thickness of the load by natural and artificial ventilation of the filter. As a loading material, volumetric loading (gravel, slag, expanded clay, crushed stone) and flat loading (plastic masses, astbocement, ceramics, metal, fabrics, etc.) are used.
Aerotanks are tanks in which treated wastewater and activated sludge are saturated with air and mixed. Air is continuously supplied to ensure normal running. After purification, the water settles. Activated sludge is separated and partly fed to a new treatment, and partly dumped on sludge sites.
Sometimes technical oxygen is used instead of air for oxidation. These structures are called oxytenki.
Anaerobic methods of biochemical purification.
Anaerobic methods are used for the digestion of sludge from the biochemical treatment of industrial wastewater, as well as for the treatment of concentrated industrial wastewater with BOD full >4-5 g/l. The end products of fermentation are alcohols, acids, fermentation gases (CO 2 , H 2 , CH 4 ).
Methane fermentation is used for wastewater treatment.
The fermentation process is carried out in digesters - hermetically sealed tanks equipped with devices for introducing unfermented and removing digested sludge (Fig.). Before being fed into the digester, the sludge should be dehydrated as far as possible.
Waste water disinfection. Wastewater must be disinfected (disinfected) before being discharged into water bodies. The effectiveness of disinfection is determined by the coli-titer (the smallest volume in mm of wastewater, which contains one E. coli). Water with a coli-titer of 0.001 is considered disinfected.
Disinfection is carried out with liquid chlorine, sodium or potassium hypochlorite, bleach, ozone, etc. The duration of contact of water with chlorine is 30 minutes. Chlorine consumption from 3 to 10 g/m 3 . Ozone is more bactericidal than chlorine. Ozone, along with disinfection, improves the physicochemical and organoleptic parameters of water. Ozone is obtained from the air in special installations. It takes 50-60 m to produce 1 kg of ozone 3 air.
Sediment processing.
After biochemical purification, a large amount of precipitation is formed. For their disinfection, anaerobic digestion in digesters, stabilization, conditioning, dehydration or heat treatment are used. Precipitation stabilization is carried out to destroy the biologically degradable part of the organic matter into carbon dioxide, methane and water. It is carried out with the help of microorganisms in aerobic and anaerobic conditions. Under anaerobic conditions, fermentation is carried out in septic tanks, two-tier settling tanks, clarifiers, superheaters, digesters.
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Presentation on the topic: Pollution and protection of the hydrosphere
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The purpose of my work is to study the current state of water resources and measures aimed at their protection by analyzing the work of the ASO plant. I set myself the following tasks: To consider the role of water in nature and human life To consider the use of water resources by man in all areas of activity To study natural and anthropogenic sources of pollution of water resources To consider the impact of various pollutants on living organisms To analyze the work of one of the largest factories in our city from the point of view of environmental protection.
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Water is the blood of the Earth. The human body is permeated with millions of blood vessels. Blood supplies every cell of the body with oxygen and nutrients, collects waste products from all corners of the body, connects all organs into a harmonious and efficient body. The same circulatory system exists on our planet. The blood of the Earth is water, and the blood vessels are rivers, streams and lakes. Water on Earth plays the same role as blood in a living organism: it removes waste generated as a result of human activity, connects various components with each other, turning them into a single system.
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Water is the most abundant substance on earth. The water shell, the hydrosphere, covers about 71% of the earth's surface. Earth's moisture is concentrated mainly in the oceans and seas. The total volume of the waters of the World Ocean is 1.5 billion km3 with an average depth of 3.8 km. Of the fresh waters of the earth's surface, the main part (79%) falls on the ice massifs of the Arctic and Antarctica, which contain 20 thousand times more fresh water than in rivers. If all the tildes melted, then the level of the World Ocean could rise by 66 m. 20% is concentrated in groundwater and only 1% is involved in the cycle.
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Man is 80% water. In the body of an adult weighing 70 kg of water is 50 kg, and the body of a newborn consists of 3/4 of the water. The richest tissue in water is the vitreous body of the eye - 99%, and the poorest - tooth enamel - 0.89%. It is interesting to compare such figures: the heart contains 80%, and the blood - 83% of water, although the heart muscle is solid and dense, and the blood is liquid. Water is essential for man. When fasting, he can lose all his fat, 50% of protein, but the loss of 10% of water by tissues is fatal.
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living organisms in the water. Water is a huge world rich in living organisms. All aquatic inhabitants must be adapted to the main features of their environment. Many species, mostly small, as if floating in the water, received the name plankton. Due to the density of water, fast swimming animals must have strong musculature and a streamlined body shape. Deep-sea animals are able to endure pressure thousands of times higher than on land. They live in complete darkness, so they have adaptations such as luminous organs. Aquatic plants are also capable of photosynthesis, but it is not possible at great depths. One of the difficulties of the life of aquatic inhabitants is a limited amount of oxygen, which leads to mass death of inhabitants when the water is polluted or heated.
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All living things need not just water, but water of a certain quality: fresh, containing 1 liter. no more than 10g. dissolved substances. As you can see, the reserves of water in the biosphere that a person can use are not so large, compared to its total amount, since the use of water concentrated in glaciers is difficult. A third of the world's population lacks clean fresh water. In economically backward countries, about 90% of the population uses unsuitable water. Water is used in agriculture, in many production cycles, in public utilities. Man uses fresh water very unreasonably and uncalculatingly. And these are not only unjustified losses of water in everyday life (for example, unclosed water taps) and municipal services (faulty underground communications). Do not lend themselves to even an approximate calculation of the loss of water in industry. For example, to get 1t. sugar requires 100 m3 of water, 1 t of paper - 250 m3, 1 t of aluminum - 120 m3. On the globe, 2.5 thousand km3 of water per year is spent on land irrigation. That is much more consumption by all other sectors of the world economy. However, the biggest threat of "water hunger" is the pollution of river waters. Growth economic activity human, is expressed in turn by an increase in the level of pollution. Every year, the discharge of waste into the Pacific Ocean is 9 million tons, and into the waters of the Atlantic 30 million tons. 30% of groundwater and 70% of surface waters have lost their potable value and have become polluted. More and more water is used to dilute the waste.
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Pollution Pollution is the introduction into the environment of any substances unusual for it or an increase in the concentration of existing ones, leading to negative consequences. All components of the hydrosphere are subject to pollution. On the territory of Russia there are more than 24 thousand enterprises that emit harmful substances into the atmosphere and water bodies. About 33% of emissions come from the metallurgical industry, 29% from the energy industry, 7% from the chemical industry, and 8% from the coal industry. These substances are not captured and neutralized in technological processes.
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CHARACTERISTICS OF THE ENTERPRISE AS A SOURCE OF POLLUTION. The ASO plant has 93 sources of air pollutant emissions, including 85 organized sources and 8 unorganized ones. 24 sources are equipped with dust and gas cleaning equipment with a cleaning ratio of 88% to 98%. Sources emit 64 pollutants and 11 groups of substances into the atmosphere that have the effect of summation of harmful effects. Substances emitted into the atmosphere in the largest amount: carbon monoxide - 411.0237 tons per year! sulfur dioxide - 8.5248 tons per year inorganic dust - 6.8903 tons per year nitrogen dioxide - 6.7343 tons per year iron oxide - 5.5683 tons per year toluene - 4.2650 tons per year white spirit - 2, 7437 tons per year xylene - 2.4149 tons per year.
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The effect of summation of harmful effects is possessed by: ammonia + hydrogen sulfide nitrogen dioxide + nitrogen oxide + fuel oil ash from thermal power plants + sulfur dioxide nitrogen dioxide + sulfur dioxide vanadium pentoxide + manganese and its compounds vanadium pentoxide + sulfur dioxide + sulfuric acidsulphurous anhydride + hydrogen sulfide hydrogen fluoride + inorganic fluorides.
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The most dangerous are oil and oil products that cause the death of plankton, change the migration routes of fish, and the content of oil in water in the amount of 0.05 mg / l makes it unsuitable for drinking. Effluent from enterprises carries various polluting agents. Among them are the following: heavy metals and their compounds (lead, organomercury compounds, etc.). dioxins are conversion products of halogenated hydrocarbons. The maximum allowable concentration for these substances in water is only 0.000035 mg / lphenol and its derivatives are highly stable, highly toxic substances that are highly soluble in water.
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They heavily pollute water bodies with surfactants, including SMS. The concentration of SMS in water at 1 mg / l causes the death of microscopic planktonic organisms, 3 mg / l - hybeldaphnia and cyclops, 5 mg / l - fish kills. If 1 m3 of wastewater discharged into rivers pollutes an average of 10 m3 of water, then 1 liter. oil renders 1 million liters of water unusable. Even more dangerous is the appearance in the river waters of pesticides (pesticides) washed off the fields. Thus, the presence in water of 2.1 parts of a pesticide per 1 billion parts of water is sufficient for the death of all organisms in it.
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Eutrophication of water bodies. Eutrophication of water bodies plays an important role in the deterioration of fresh water quality. A person brings fertilizer to the fields, and during rains and floods, they are carried into reservoirs. The rapid accumulation of organic matter, nitrogen and phosphorus fertilizers in water bodies leads to abundant reproduction of floating blue-green algae. The water becomes cloudy, the decomposition of organic substances begins in it, the supply of oxygen to the water deteriorates, crustaceans and fish die, and the water acquires an unpleasant taste. Dangerous pollutants of water bodies are salts of heavy metals - lead, iron, copper, mercury. In the mid 50s. XX century people learned about the terrible "Minomata disease", the cause of which was mercury compounds discharged into the coastal waters of Japan. Mercury penetrated into marine products, and with them - into human bodies. About 100 thousand Japanese became victims of this disease.
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Bioindicators. Bioindicators are living organisms that are sensitive to environmental pollution. The purity of water, its richness in oxygen is evidenced by the presence of caddisfly larvae, which die even with slight pollution. Tubifik - an indicator of severe pollution of the reservoir. He prefers rather polluted, oxygen-poor reservoirs with silty soils - mostly small rivers, especially if they are dumped with wastewater from industrial enterprises. Tubifex feed by swallowing silt and sand from the bottom of the reservoir, while organic matter from the soil is absorbed by the body. In this regard, the tubule contributes to the biological purification of water.
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Purification of water with the help of living organisms. The quality of water in reservoirs largely depends on the filtering animals. Lamellar-gill mollusks (mussels, barley, toothless) with cilia on the oral lobes drive water to the mouth opening and sort out the suspension. Small crustaceans strain the food suspension with thick brushes of bristles on their limbs. Midge larvae in streams filter food with tufts of bristles on their heads, and mosquito larvae with brushes on their upper lip. Some fish filter water through the gill apparatus, like a silver carp and a whale shark. Filtration feeding is observed in 40 thousand species of aquatic animals. Perlovitsa purifies up to 16 liters of water per day. In ponds and lakes, small crustaceans pass the entire volume of water through their filter apparatus in just one day. 1 m2 of shallow sea water, densely populated with mussels, can purify up to 280 m3 of water per day. Thus, the purity and transparency of natural waters is the result of the activity of living organisms.
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Water purification with treatment facilities. Depending on the degree and nature of pollution, mechanical, chemical and biological methods of wastewater treatment are used. Mechanical methods remove coarse dispersed impurities using gratings, sieves, filters, sedimentation tanks, oil traps. Chemical treatment is the addition of reagents to wastewater that promote the formation of precipitates from colloidal and some true solutions. Biological wastewater treatment under artificial conditions is carried out in special facilities - biofilters, aerotanks. In Russia, modern treatment facilities are available only at large industrial and economic facilities. And small enterprises, agricultural farms, settlements have, at best, primitive sedimentation tanks or dump polluted water into reservoirs without treatment.
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Surface runoff through the storm water well enters the storage tanks. The rainwater accumulated in these tanks is pumped for treatment. A thin-layer settling tank, where preliminary treatment of surface wastewater from suspended solids (SS) takes place. The characteristics of the sump provide stable operation with a cleaning effect of at least 90%. From the sump, wastewater enters the oil trap, which provides a residual concentration at the outlet of not more than 12 mg/l. at the same time, the separated oil products are accumulated in an isolated container - a collection of oil products. After the oil trap, wastewater is fed by gravity into the filter units, in which fine filters are located, designed to remove explosives and oil products by filtration and sorption. In the process, the water passes through two filters. In the 1st stage of the non-pressure filter, the residual concentrations of explosives and oil products after the polyester filter are 4-5 and 1-2 mg/l. It is also here that the main amount of substances entering the fine filters is retained. In stage II, water passes through a layer of granular activated carbon. At the filter outlet, the concentration of oil products does not exceed 1.2 mg/l, the concentration of explosives does not exceed 6 mg/l. The movement of water through a non-pressure filter occurs from the bottom up by gravity under the pressure of a liquid column. The second filter is pressure. Through it, water is supplied by a pump through a calibrated hole, simultaneously with the pump, the installation of a UV disinfection lamp that has passed through the pressure water filter is turned on. Here the final purification of water to the required values takes place. Purified water, after treatment facilities, is discharged through the pipeline into the existing outlet collector, and its quality complies with the established standards.
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Protection of water resources. The most important measure for the protection of water resources is their careful use. Now, when the fields are irrigated, about 25% of the water is lost through filtration and evaporation. Reliable waterproofing of the bottom and walls of the channels allows to reduce unproductive water consumption and prevents soil salinization in arid areas. When using sprinkling installations, 5-6 times less water is consumed than with conventional irrigation. Another way to save water for irrigation is to bring water directly to the root system of fruit trees using droppers. This allows you to avoid excessive evaporation and strictly dose the flow of water to the plants. The most effective way to protect water bodies from pollution is to create waste-free production, when waste from one stage of the production cycle is used as raw material for another.
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For more effective protection of water resources, a law on water protection was issued. The Water Code (October 18, 1995) regulates the use and protection of water resources, establishes state ownership of most water bodies, determines the procedure for establishing water protection zones, the regime for using their territories, conducting state examination of project documents for the construction and reconstruction of economic and other objects that affect the state of water bodies, state monitoring of water bodies and protect them from pollution.
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Conclusions. Water plays a very important role in human life and in nature. Water is used in all spheres of human economic activity. There are natural and anthropogenic sources of water pollution. unacceptably large. In Russia, modern treatment facilities are available only at large industrial and economic facilities. And small enterprises usually dump polluted water into reservoirs without treatment. Measures aimed at protecting water resources have been developed.
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References Rozanov S.I., Lasukov R.Yu. Fundamentals of system ecology 1997 Ponomareva I.N. Ecology 2001 Encyclopedia for children. T. 3. Geography. Avanta +. 2003 Ecology. Tutorial. 1С CD diskInternet Zverev I.D. Reading book on human anatomy, physiology and hygiene. 1983
Surface waters are protected from clogging, pollution and depletion.
For a warning from clogging take measures to prevent the entry of construction waste, solid waste, developed soil and other items into water bodies and rivers that adversely affect water quality, fish habitats, etc.
The most important and very complex problem is the protection of water from pollution. To this end, the following activities are envisaged:
· development of non-waste and waterless technologies, introduction of recycling water supply systems, waste disposal;
· purification of industrial, municipal and other waste waters;
transfer of wastewater to other enterprises that impose less stringent requirements on water quality and if the impurities contained in it do not have a harmful effect on the technological process of these enterprises, but rather improve the quality of products (for example, transfer of wastewater from chemical enterprises to construction enterprises production);
sewerage and sanitary cleaning of cities;
· treatment of surface runoff of urban and industrial areas;
Creation of water protection zones.
Wastewater Treatment Methods. In view of the huge variety of wastewater composition, there are various methods for their treatment: mechanical, physico-chemical, chemical, biological, etc. Depending on the nature of the pollution and the degree of harmfulness, wastewater treatment can be carried out by any one method or a set of methods (combined method) .
At mechanical cleaning by filtering, settling and filtering, insoluble mechanical impurities are removed. For this purpose, gratings, sand traps, sand filters, and various types of sedimentation tanks are used. Substances floating on the surface of wastewater (oil, resins, oils, fats, polymers, etc.) are retained by oil and grease traps or other types of traps by draining the upper layer containing floating substances.
Chemical and physico-chemical methods are used to treat industrial wastewater.
At chemical cleaning into waste water special reagents are introduced (lime, soda ash, ammonia, etc.), which interact with pollutants and precipitate.
At physical and chemical purification using methods of coagulation, sorption, flotation, etc.
For the treatment of municipal, industrial effluents of pulp and paper, oil refineries, food enterprises after mechanical cleaning use biological method. This method is based on the ability of natural microorganisms to use for their development, organic and some inorganic compounds contained in wastewater. Cleaning is carried out on artificial structures (aerotanks, digesters, biofilters, etc.) and in natural conditions (filtration fields, irrigation fields, biological ponds, etc.). Waste water treatment generates sediment, which is removed for drying on silt pads, and then used as a fertilizer. However, in the biological treatment of municipal wastewater, together with industrial wastewater that contains heavy metals and other harmful substances, these pollutants accumulate in sludge and their use as fertilizers is excluded. There is a problem of handling sewage sludge in many cities of Ukraine, including Kharkov.
An important protective role in any water body is played by water protection zones - These are special zones arranged along the banks of rivers, lakes, reservoirs. The main purpose is to protect water bodies from pollution, clogging, erosion sediments by surface runoff. The width of water protection zones can range from 100 to 300 m or more. Within the limits of the water protection zone, the soil must be fixed with vegetation, protective forest strips should be planted, economic activities are prohibited: plowing land, grazing livestock, using pesticides, fertilizers, performing construction work, placing warehouses, garages, livestock complexes, etc.
Water quality control spend for assessment of the possibility of its use for household, drinking, cultural and household, fishery and technical purposes. To assess the quality of water, its composition and physical properties are analyzed. Temperature, smell, taste, transparency, turbidity, dissolved oxygen content, biochemical oxygen demand, acidity, content of harmful substances, as well as the number of Escherichia coli in one liter of water are determined. All of the above indicators should not exceed the regulatory requirements.
Introduction
1.1 Measures to protect the waters of the seas and the World Ocean
1.2 Protection of water resources from pollution and depletion
2. Features of pollution of the World Ocean and the surface of land waters
2.1 Organic and mineral pollution
2.2 Organic liquids and gases, carcinogens
3. Fresh water problems
3.1 Fresh water resources
Conclusion
List of used literature
Introduction
Water reserves on Earth are huge, they form the hydrosphere - one of the most powerful spheres of our planet. The hydrosphere, lithosphere, atmosphere and biosphere are interconnected, penetrate one another and are in constant, close interaction. All spheres contain water. Water resources are composed of static (secular) reserves and renewable resources. The hydrosphere combines the World Ocean, seas, rivers and lakes, swamps, ponds, reservoirs, polar and mountain glaciers, groundwater, soil moisture and atmospheric vapor.
Water is one of the most important life-supporting natural environments formed as a result of the evolution of the Earth. It is an integral part of the biosphere and has a number of anomalous properties that affect the physicochemical and biological processes occurring in ecosystems.
1. Hydrosphere and its protection from pollution
Pollution - visible or invisible, on land, air or water - is now an undesirable but so familiar part of our lives. Pollution can be described as the introduction by mankind of substances or materials that degrade the quality of the environment. These substances (pollutants) are introduced into the environment by man, and not as a result of natural oil seeps or volcanic eruptions, which can be called natural pollutants. Many pollutants are synthetic substances that are alien and therefore dangerous for us and other organisms.
Human impact on the living resources of the biosphere, including the World Ocean, in our time is not limited to the removal of bioproducts, cultivation and changes in the composition and size of populations. Over the past decades, the influence of industrialization and urbanization of modern society, intensification and chemicalization has been growing and expanding especially rapidly. Agriculture and other attributes of scientific and technological progress, which are associated with pollution of the biosphere and the emergence of new environmental factors. A special place in this complex and multifaceted problem is occupied by the issues of pollution of the oceans. Many, if not most, of the toxic substances released from human control on land end up in the marine environment, creating a situation of local, regional or global pollution of the seas and oceans.
Recently, pollution of the seas and the World Ocean as a whole (background pollution) has caused great concern. Global (background) pollution of the hydrosphere is determined mainly by atmospheric transport and removal of pollutants from the atmosphere. With the exception of crude oil, all pollutants enter the oceans largely through the atmosphere. More than 109 tons of solid, vapor and gaseous compounds are annually burned and released into the atmosphere. Significant amounts of products such as DDT, polychlorinated biphenyls, mercury, lead, and ash were found in atmospheric aerosols and ocean fallout.
The main sources of pollution are domestic and industrial sewage (60% of large cities are concentrated in coastal areas), oil and oil products, and radioactive substances. Oil pollution and radioactive substances are especially dangerous. The enterprises of seaside cities throw thousands of tons of various, as a rule, untreated waste into the sea, including sewage. Polluted river waters are carried into the seas. Oil and oil products get into the water as a result of washing tanks, containers in which oil is transported. A huge amount of oil gets into the ocean and into the seas in case of accidents with tankers, oil pipelines in oil fields, during the exploration and exploitation of oil fields in the zone of continental shelves. Oil well accidents release many thousands of tons of oil into the sea.
Pollution is the cause of the death of marine animals, crustaceans and fish, waterfowl, seals. There are known cases of the death of about 30 thousand sea ducks, the mass death of starfish in the early 1990s in the White Sea. It is not uncommon for beaches to be closed due to dangerous concentrations of pollutants in sea water.
1.1 Measures to protect the waters of the seas and the World Ocean
Measures to protect the waters of the seas and the World Ocean are to eliminate the causes of deterioration in the quality and pollution of waters. Special measures to prevent pollution of sea water should be envisaged in the exploration and development of oil and gas fields on the continental shelves. It is necessary to impose a ban on the disposal of toxic substances in the ocean, maintain a moratorium on testing nuclear weapons under water. Rapid action should be taken to eliminate the consequences of accidents and disasters in which toxic products enter the ocean. The problem of protecting the waters of the World Ocean is global, it concerns all states of the planet. To protect the waters of the World Ocean, joint efforts of all states of the world community, the UN and its departments are necessary. To a large extent, such measures can be successful with the participation of states in international environmental programs that are developed and proposed by the relevant conventions and provided for by international agreements.
1.2 Protection of water resources from pollution and depletion
The scale of pollution and depletion of water resources is now rampant. There is an acute problem of shortage of fresh water in densely populated areas, large industrial centers, in areas of irrigated agriculture. The lack of clean drinking water, pollution of water bodies are the cause of many human diseases, have a detrimental effect on the flora and fauna of the Earth. In many places, freshwater pollution is moving from local to regional.
The protection of water resources as an integral part of the protection of the natural environment is a set of measures (technological, biotechnical, economic, administrative, legal, international, educational, etc.) aimed at rational use of resources, their conservation, prevention of depletion, restoration of natural relationships balance between human activities and the environment.
Principles of water protection.
The important principles of water protection are:
prevention - prevention of negative consequences of possible depletion and pollution of waters;
the complexity of water protection measures - specific water protection measures should be an integral part of the overall environmental program;
ubiquity and territorial differentiation;
focus on specific conditions, sources and causes of pollution;
scientific validity and the availability of effective control over the effectiveness of water protection measures.
The most important technological measures for the protection of water resources are the improvement of production technologies, the introduction of waste-free technologies. Currently, a recycling water supply system, or reuse of water, is being used and improved.
Since it is impossible to completely avoid water pollution, biotechnical measures for the protection of water resources are applied - wastewater treatment from pollution. The main cleaning methods are mechanical, chemical and biological.
During mechanical wastewater treatment, insoluble impurities are removed using gratings, sieves, grease traps, oil traps, etc. Heavy particles are deposited in settling tanks. Mechanical cleaning can free water from insoluble impurities by 60-95%.
In chemical treatment, reagents are used that convert soluble substances into insoluble ones, bind them, precipitate and remove them from wastewater, which is further purified by 25-95%.
Biological treatment is carried out in two ways. The first - in natural conditions - on specially prepared filtration (irrigation) fields with equipped maps, main and distribution channels. Purification occurs naturally by filtering water through the soil. The organic filtrate is subjected to bacterial decomposition, exposure to oxygen, sunlight and is further used as a fertilizer. A cascade of settling ponds is also used, in which water self-purification occurs naturally. Second - fast track wastewater treatment - produced in special biofilters through porous materials from gravel, crushed stone, sand and expanded clay, the surface of which is covered with a film of microorganisms. The process of wastewater treatment on biofilters is more intensive than on filtration fields. Currently, almost no city can do without treatment facilities, and all of these methods are used in combination. This gives a good effect.
In many countries, the problem of protecting water from pollution has begun to be addressed at the government level, and large funds have been allocated for its solution. However, some industrial countries approached the restoration of order in their inland waters in a very peculiar way. They, on the one hand, developed measures to prevent or eliminate pollution, investing large sums of money in this, on the other hand, they began to transfer enterprises that pollute water bodies the most to developing countries. This helped to improve the situation in the most industrialized countries, but did not remove the problem on the planet as a whole, as catastrophic pollution of rivers and water bodies began in developing countries continued pollution of the world's oceans.
2. Features of pollution of the World Ocean and the surface of land waters
Sources of pollution of the oceans are many objects of human economic activity. Main pollutants: industrial and municipal waste, oil and oil products, vehicle emissions, waste from agriculture and livestock complexes, including pesticides and mineral fertilizers, radioactive substances.
The main types of pollution are: physical (determined by smell, color); chemical (increased mineralization - the presence of chlorides, sulfates, nitrates, heavy metal ions, dissolved hydrogen sulfide and other gases); organic (hydrocarbons - oil and oil products, phenol); biological (E. coli, bacteria and other microorganisms); radioactive, thermal, mechanical (turbidity, the presence of immiscible liquids). It should be borne in mind that many substances accumulate in organisms, their concentration increases in animals located at the top of the trophic pyramids.
Pollutants can be divided into mineral and organic or, more logically, into: organic non-toxic, mineral and organic toxic (including radioactive), mixed.
2.1 Organic and mineral pollution
Organic non-toxic pollutants include fecal effluents, timber floating waste, cellulose fibers in the discharges of paper mills, and some others. They can cause the death of hydrobionts through the deterioration of the oxygen regime, the formation of hydrogen sulfide, or due to mechanical impact.
Mercury and lead are the most widespread pollutants of surface and, in some cases, groundwater. In Sweden, many of the freshwater and marine fish contain mercury in the range of 200-1000 ng/kg. An increased content of mercury in the formed elements and blood plasma and hair of people who ate fish was noted. Mercury has been found in the meat of eagles, pheasants and other animals. An increase in mercury along the links of the food chain has been established. Rivers annually carry about 5000 tons of mercury and its compounds into the oceans, of which, for example, methylmercury has a higher toxicity and intensely heats up in the tissues of hydrobions. The average concentration of mercury in sea water today is 0.03 µg/l, and bottom sediments are enriched with mercury even more.
Lead also plays an important role in water pollution. Rain alone annually flushes out 250,000 tons of lead from the atmosphere over the ocean and 100,000 tons over land. 150,000 tons of lead comes from soils annually. In this regard, over 45 years, the lead content in sea water has increased from 0.01-0.02 to 0.07 mg/kg.
Other metals, such as zinc, nickel, cadmium, and chromium, also enter the reservoirs in significant quantities. With their participation, the active centers of a number of enzymes are neutralized, and some proteins are destructed. There are cardiovascular diseases.
Radioactive isotopes, or radionuclides, are of great importance in the pollution of water bodies. The radiation of radionuclides is capable of moving electrons from one atom to another, as a result of which each of them acquires a charge. The magnitude of contamination of water bodies with radionuclides can be judged from the fact that only the United States dumped several tens of thousands of curies of waste into the Pacific and Atlantic oceans from 1946 to 1963. Radioactive contamination of water bodies also occurs as a result of the deposition of radionuclides from the atmosphere. The surface of the water is 1.5-2 times more effective collector of radioactive aerosols than the land.
2.2 Organic liquids and gases, carcinogens
In addition to the well-known groups of global toxicants (oil and oil products, heavy metals, organochlorine compounds), two more types of substances should be mentioned, the release of which into the environment has taken on a very large scale - organic liquids and gases (dichroethane, freons, solvents) and carcinogens, possessing blastomogenic properties (polycyclic aromatic hydrocarbons such as benzopyrene).
We should also not forget about the processes of eutrophication associated with the removal of organic substances, fertilizers, detergents and other phosphorus and nitrogen compounds into coastal waters, leading to the intensive development of phytoplankton and some species of bottom algae and secondary pollution of the sea by the products of their metabolism and decay.
In the last decade, along with eutrophication, pollution of both surface and ground waters has increased significantly as a result of the ingress of toxic components into them that are alien to aquatic ecosystems and deeply disrupt their normal functioning. The danger of pollution is associated not only with the direct negative effect of toxicants on the functioning of aquatic organisms, but also with the fact that toxic components transform in the aquatic environment, form complexes of metal-boundary and inorganic compounds, and turn into other substances, often more toxic than the original ones. For example, metals in the form of ions in some cases turn out to be less toxic to hydrobionts than their organometallic compounds having methyl, ethyl, or phenyl radicals. Similar changes in the aquatic environment occur with polyphenols, which are converted into quinones, which are more toxic than the original compounds.
An equally important role in the pollution of continental waters and the World Ocean is played by oil and oil products. The amount of oil entering the World Ocean is estimated at 5-10 million tons per year.
Pesticides (chlorinated hydrocarbons, including the DDT group, organic phosphates, arsenic-containing drugs and carbamates) entering water bodies with surface and subsoil runoff, as well as wastewater, are among the significant factors of pollution of natural water bodies.
It is impossible not to mention household waste, which, along with the eutrophic influence, can also cause pollution of natural waters. For example, in the United States, 15 kg of solid waste per person is dumped into the sewer each year.
Consequently, despite the gigantic volumes of the water masses of our planet, man has become one of the essential links in the formation of their qualitative, and often quantitative indicators.
3. Fresh water problems
The problem of providing fresh water is currently one of the most pressing issues, since water scarcity in some cases becomes a limiting factor in the process of technological progress, and the future of mankind largely depends on its solution.
The intensive use of water reserves of surface and underground sources in industrial, domestic and drinking water supply, their pollution, eutrophication, and warming lead to a reduction in the relatively small resources of clean fresh water available on the globe (3% of all earthly moisture), a sharp deterioration in its quality and an increase in water deficit. With the current scale of anthropogenic impact on the biosphere, the quality of natural waters is formed not only as a result of the functioning of natural ecosystems, but also due to the production activities of society, and the human impact on the hydrosphere is multifaceted, significant and often negative.
As a result, already today more than 200 million people in the world are completely deprived of clean drinking water.
The total water supply on the globe is over 1370 million km3 and is composed mainly of the water of the World Ocean. The volume of fresh water is only 32.2 million km 3, including glaciers (25 million km 3), ground and underground waters (3720 thousand km 3), soil moisture (90 thousand km 3), lakes (120 thousand km3), rivers (12 thousand km3) and atmospheric vapors (14 thousand km3).
3.1 Fresh water resources
The available reserves of water resources and a number of grandiose technical solutions to water problems make it possible today to provide the world with almost the required volume of water supply, while simultaneously discharging 450 km world reserves.
Fresh waters make up an insignificant (about 2% of the hydrosphere) share of the total water reserves in nature. Fresh water available for use is found in rivers, lakes and groundwater. Its share of the entire hydrosphere is 0.3%. Fresh water resources are distributed extremely unevenly, often the abundance of water does not coincide with areas of increased economic activity. In this regard, there is a problem of lack of fresh water. It is exacerbated by the ever-increasing volumes of its use. Now the consumption of water in the national economy quantitatively exceeds the total use of all other natural resources, since production in the main industries consumes a huge amount of fresh water. So, for the processing of 1 ton of oil, it is necessary to spend about 60 tons of water, for the manufacture of 1 ton of conditional fabric products - 1100 tons, synthetic fiber - up to 5000 tons of water. For the cultivation and production of 1 ton of wheat, 2 tons are spent, and rice - over 25 tons of water. Water turns into the most precious raw material, which cannot be replaced. The reserves and availability of water resources dictate the location of new industries, and the problem of water supply is becoming one of the most important in the life and development of human society.
3.2 Reasons for lack of fresh water
The problem of fresh water shortage arises for several reasons, the main of which are: the uneven distribution of water in time and space, the growth of its consumption by mankind, the loss of water during transportation and use, the deterioration of water quality and its pollution. Anthropogenic causes of depletion and pollution of fresh water include the following: abstraction of surface and groundwater; spillway from mines, galleries; development of deposits - solid minerals, oil and gas, industrial waters, sulfur smelting; urbanization - residential buildings, energy facilities (nuclear power plants, thermal power plants). Industrial enterprises strongly pollute fresh waters: chemical, food, pulp and paper, ferrous and non-ferrous metallurgy, oil refining, building materials, machine-building. Pollution enters water bodies during the construction of pits, tunnels, subways, hydraulic structures, and drainage works. Water is polluted by transport, water, heat, gas communications, sewerage, power lines. The most important water pollutant is agricultural production: agriculture, land reclamation, animal husbandry. The danger of fresh water pollution is associated with the storage of raw materials, household, industrial and radioactive waste, mineral fertilizers, pesticides, and petroleum products. Pollution occurs when gases and liquids are pumped into the subsoil, oil deposits are flooded. Burial of highly toxic waste. The grandiose projects for the transformation of nature do not take into account the possible pollution of fresh waters: the transfer of river flow, melioration, windbreaks. Fresh water pollution is associated with military exercises, testing and elimination of nuclear, chemical and other types of weapons.
The growth of fresh water consumption by the population on the planet is determined by 0.6-2% per year. At the beginning of the 21st century, the total water intake is expected to be 12-24 thousand km3. Water consumption is increasing due to the growth of wealth, this can be seen in the following example. Water consumption by one urban resident of the southern regions of Russia is: in a house without sewerage 75, in a house with sewerage 120, with a gas water heater 210 and with all amenities 275 l / day. For a city in central Russia, the rate of water consumption according to the "Norms of Household and Drinking Consumption for Settlements" (SNiP-II.31 - 74) is: in houses without baths 125-160, with baths and heaters 160-230 and with central hot water supply 250-350 l / day.
Losses of fresh water grow with the growth of its consumption per capita and are associated with the use of water for household needs. Most often this is due to the imperfection of the technology of industrial, agricultural production and public services. Water losses from water-bearing communications in Russian cities are 30-35% In cities of regional significance, water losses are approximately 10-15 million tons per year and double every 5 years. Large losses of fresh water occur during the development of mineral deposits, during construction drainage of urban areas. Water losses are largely associated with insufficient knowledge of natural conditions (geological-lithological and hydrogeolithological, climatic and meteorological, biological properties), internal patterns and mechanisms of ecosystem development. When creating reservoirs, the increase in filtration into their sides and the increase in evaporation with an increase in the water surface are not always taken into account. The creation of a cascade of ponds on rivers damages river flow. Drainage of swamps leads to a decrease in groundwater reserves, disrupts the centuries-old moisture balance and circulation, changes the species composition of biocenoses, etc. The construction and use of canals contributes to the sharp salinization of soils, waterlogging and huge losses of fresh water.
The deterioration of water quality is associated with the ingress of products of human activity both directly into the water from rivers and other surface water bodies, groundwater, and through the atmosphere and soil. The deterioration of fresh water quality is the most dangerous and is becoming a threat to human health and the spread of life on Earth. Its extreme state is catastrophic water pollution.
Deterioration of quality and pollution of water, depletion of water resources occurs constantly. This is due to contact with water and the transfer of various substances. Changes are cyclical, less often spontaneous: they are associated with volcanic eruptions, earthquakes, tsunamis, floods and other catastrophic phenomena. Under anthropogenic conditions, such changes in the state of water are unidirectional: foreign substances that enter the water accumulate in it, worsening its organoleptic properties. Water pollution occurs when the amount of foreign substances contained in water, especially those that have an adverse effect on humans, animals and plants, reaches critical values.
Conclusion
How can we expect the near future for the World Ocean, for the most important seas?
In general, for the World Ocean, it is expected to increase its pollution by 1.5-3 times over the next 20-25 years. Accordingly, the environmental situation will also worsen. The concentrations of many toxic substances can reach a threshold level, and then the natural ecosystem will be degraded. It is expected that the primary biological production of the ocean may decrease in a number of large areas by 20-30% compared to the current one.
The path that will allow people to avoid the ecological impasse is now clear. These are non-waste and low-waste technologies, the transformation of waste into useful resources. But it will take decades to bring the idea to life.
The future of the biological resources of the World Ocean is under serious threat and requires effective measures to protect it from pollution. The oceans should be an arena for international cooperation in the field of rational use and protection of its resources, involving participation in international programs all states interested in the preservation of the World Ocean as the most important ecosystem of the world.
List of used literature
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