Ways to protect water resources. Water resources and their protection

Federal legislation and protection of water bodies

Water legislation includes the Water Code Russian Federation and federal laws and other regulatory legal acts adopted in accordance with it, as well as laws and other regulatory legal acts of the constituent entities of the Russian Federation (republics, territories, regions).

The purpose of water legislation is to regulate relations in the field of use and protection of water bodies. At the same time, the use of water bodies for drinking and household water supply is a priority. For this type of water supply, it is necessary to use surface and underground water bodies protected from clogging and pollution.

All water users are obliged by law to reduce withdrawals and losses of water, to prevent clogging, depletion and pollution of water bodies. It is prohibited to discharge sewage (WW) into water bodies if the latter are classified as specially protected, contain natural healing resources, are located in places of mass recreation of the population or resort areas, as well as in spawning and wintering areas valuable species fish, etc.

The main role in water protection is played by the state accounting of surface and ground waters, which is carried out for the purposes of current and long-term planning of the rational use of water resources, their restoration and protection. It is based on data state monitoring and accounting data provided by water users. Codes of systematized data on water bodies, water resources, regime, quality and use of water, as well as on water users are included in the water cadastre.

The Water Code of the Russian Federation prohibits putting into operation:

any objects that are not equipped with treatment facilities and devices that prevent clogging, depletion and pollution of water bodies;

waste and catchment facilities, as well as hydraulic structures (HTS) without fish protection devices;

objects of industry, agriculture and other complexes that do not have sanitary protection zones;

irrigation, watering and drainage systems, reservoirs, dams and canals until the completion of measures that prevent their harmful effects on water bodies.

An important role in the protection of water resources is played by the licensing of water use, as well as the discharge of waste and other waters. The procedure for licensing water use is regulated by Art. 48-53 and 83 of the Water Code of the Russian Federation, as well as the Decree of the Government of the Russian Federation "On approval of the Rules for the provision of state-owned water bodies for use, the establishment and revision of water use limits, the issuance of a license for water use and a distribution license."

Violation of the requirements for the protection and rational use of water bodies entails the restriction, suspension and even prohibition of the operation of economic and other objects that have a negative impact on the state of water bodies. The decision on this is made by the Government of the Russian Federation or bodies executive power its subjects. Preliminarily, a presentation is given by a specially authorized state body for managing the use and protection of the water fund, specially authorized state bodies in the field of protection of environmental protection systems, and a state body for sanitary and epidemiological supervision.

Monitoring of water bodies

State monitoring of water bodies, being an integral part of the system of state monitoring of the natural environment, includes monitoring of surface water bodies on land and seas, monitoring of underground water bodies, monitoring of water management systems and structures.

It provides for: 1) constant monitoring of their condition, qualitative and quantitative indicators of both surface and groundwater; 2) collection, storage and processing of observational data; 3) creation and maintenance of data banks; 4) assessment, forecasting of changes in the state of water bodies and the transfer of relevant information to government bodies of the Federation and its subjects.

State monitoring of water bodies is carried out by the Ministry of Natural Resources (MNR), federal Service for hydrometeorology and environmental monitoring (Roshydromet) and other specially authorized state bodies in the field of environmental protection.

The Ministry of Natural Resources of the Russian Federation is responsible for the development of a network of stations and observation posts at water bodies, the development of automated information systems(AIS) for the conduct of state monitoring of water bodies, the creation of an observation network of posts on water management systems and structures. Roshydromet monitors the pollution of land surface waters, covering 154 reservoirs and 1172 watercourses, where hydrochemical parameters are studied.

The Sanitary and Epidemiological Service of Russia is responsible for the sanitary protection of water bodies. It has 2,600 sanitary and epidemiological institutions, 35 research institutions of a hygienic and epidemiological profile. In addition, there is a network of sanitary laboratories at enterprises engaged in studying the composition of wastewater and the quality of water in reservoirs.

Currently, much attention is paid to the deployment of a network of automated stations that are able to measure and control changes in dozens of water quality indicators, and very quickly.

Schemes for the integrated use and protection of waters

In order to develop comprehensive measures aimed at meeting the prospective water needs of the population and National economy in combination with water protection, general, basin and territorial schemes are drawn up.

General schemes for the integrated use and protection of waters determine the principal directions for the development of the country's water management, which makes it possible to quite clearly identify the technical and economic feasibility and sequence of the largest water management measures. Basin schemes for river basins and other water bodies are developed on their basis. Territorial schemes developed on the basis of the general and basin schemes cover specific economic regions of the country and subjects of the Russian Federation.

To coordinate the activities of various water users aimed at the restoration and protection of water bodies within the basin, the Water Code of the Russian Federation requires the drawing up of a so-called basin agreement on the restoration and protection of water bodies. These agreements are concluded between a specially authorized government agency management of the use and protection of the water fund and by the executive authorities of the subjects of the Federation, which are located within the basin of a water body (for example, Lake Baikal).

The basin agreement is based on water management balances, schemes for the integrated use and protection of water resources, state programs for the use, restoration and protection of water resources, and without fail takes into account the proposals of state authorities of the constituent entities of the Russian Federation (territories, regions, etc.).

In 1996, the Government of Russia adopted a resolution “On the Procedure for the Development and Approval of Standards for Maximum Permissible Harmful Impacts on Water Bodies”, according to which MPE standards for water bodies should be developed and approved for the basin of a water body or its section in order to maintain surface and groundwater in proper condition.

Surface water protection

Surface waters are waters permanently or temporarily located on the earth's surface. These are the waters of rivers, temporary streams, lakes, reservoirs, ponds, reservoirs, swamps, glaciers and snow cover.

Measures for their protection are provided for in the Rules for the Protection of Surface Waters, approved by the USSR State Committee for Nature Protection dated February 21, 1991. Particular attention is paid to the protection of water bodies when wastewater is discharged into them.

Surface waters are protected from clogging, depletion and pollution. To prevent clogging, measures are taken to prevent the ingress of garbage, solid waste and other objects that adversely affect water quality and habitat conditions for aquatic organisms. Strict control over the minimum allowable runoff of water, limiting their irrational consumption contribute to the protection of surface waters from depletion.

Very important and difficult problem is to protect surface water from pollution. To this end, a number of measures are envisaged, in particular: monitoring of water bodies; created-

Nie water protection zones; development of non-waste and waterless technologies, as well as systems of circulating (closed) water supply; wastewater treatment (industrial, domestic and others); purification and disinfection of surface and ground waters used for drinking water supply and other purposes.

Organization of water protection zones

To maintain water bodies in a state that meets environmental requirements, excludes pollution, clogging and depletion of surface waters and preserves the habitat of animals and plants, water protection zones are organized. They are territories adjacent to the water area of rivers, reservoirs and other surface water bodies; they establish a special regime for the use and protection of natural resources, as well as the implementation of other activities. Within these zones, coastal protective strips are established, where it is not allowed to plow the land, cut down forests, place farms, etc.

According to the Water Code of the Russian Federation, the government of the country is entrusted with the duty to establish the size and boundaries of water protection zones and their coastal protective strips. Thus, the minimum width of these zones for lakes from the average long-term water level in summer period and for reservoirs from the water's edge at a normal backwater level with a water area of up to 2 km2 is 300 m, more than 2 km2 - 500 m.

A similar indicator for rivers is determined by the length of the river: from the source to 10 km - 15 m; from 11 to 50 km - 100 m; from 51 to 100 km - 200 m; from 201 to 300 km - 400 m; over 500 km - 500 m.

Great importance in the matter of protecting surface waters from clogging and pollution, they have water-protective forest plantations around natural and artificial reservoirs and watercourses. They are designed to protect them from the destructive effects of winds and water entering them from the catchment area, as well as to reduce water loss to evaporation. Forest plantations improve the water regime of reservoirs, the sanitary and hygienic conditions of the coast and its landscape and decorative design, the quality of water in reservoirs, reduce their siltation, and reduce the loss of land due to the processing of banks by waves (abrasion). Water protection forest plantations located around drinking reservoirs must meet the sanitary and hygienic requirements that apply to drinking reservoirs. They include up to 50% of conifers, which are placed in the extreme 2-3 rows from the side of the reservoir to protect its mirror from falling leaves.

In addition to water protection zones, in order to ensure protection, sanitary protection districts can also be established. They are established in order to protect water bodies used for drinking and domestic water supply, as well as containing natural healing resources.

Domestic wastewater treatment

During wastewater treatment (SW), the destruction or extraction of harmful substances from them is carried out.

A complex of engineering structures and sanitary measures that ensure the collection and removal of polluted wastewater from populated areas and enterprises, their purification, neutralization and disinfection (destruction of dangerous microorganisms) is sewage.

According to Yu.V. Novikov (1998), power treatment facilities sewerage in the country exceeds 58 million m3 per day, and the length of sewer networks in settlements has reached 114 thousand km. Through sewerage systems, cities and other settlements discharge 21.9 billion m3 of wastewater per year; of which only 76% passes through treatment facilities. Annually, 13.3 billion m3 of waste water enters surface water bodies (and these are the main sources of drinking water supply) through communal sewerage systems, of which 92% is discharged contaminated and only 8% of wastewater is treated at treatment facilities to the established standards. According to official data, 60% of operated sewage treatment plants are overloaded, about 38% have been in operation for 25-30 years and require urgent reconstruction. Add to this that 52 cities and 845 urban-type settlements do not have centralized sewerage systems at all.

In order to provide economic incentives for environmental protection measures, the Government of the Russian Federation in 1996 adopted a resolution "On the collection of fees for the discharge of wastewater and pollutants into the sewerage systems of settlements", according to which the procedure and amounts of payments for the discharge of wastewater and pollutants into the sewerage systems of settlements are determined. from enterprises and organizations diverting their CBs to these systems. At the same time, the fee is distributed in the ratio: to the federal budget - 40%, to the budget of the constituent entities of the Federation - 60%. The funds received should be directed to the restoration and protection of water bodies.

Cleaning of domestic wastewater can be carried out by mechanical and biological methods. During mechanical cleaning, WW is divided into liquid and solid parts. The liquid is further subjected to biological purification, which can be natural and artificial. Natural biological treatment of wastewater is carried out on agricultural fields of irrigation and filtration, as well as in biological ponds. Artificial biological treatment is carried out on special facilities (biofilters, aeration tanks). The resulting sludge is processed on sludge sites or in special devices - metatanks.

Industrial wastewater is pre-passed through local treatment facilities, where it is freed from suspended particles or specific toxic components using mechanical, chemical or physico-chemical cleaning methods.

In practice, several types of irrigation systems are used: continuous flooding, flooding along furrows and strips, sprinkling, subsoil irrigation. The latter method most satisfies the sanitary-technical, epidemiological, agro-economic, water management and, importantly, aesthetic requirements. When using treatment facilities with irrigation fields and with year-round intake of WW with seasonal regulation of their supply, watering is carried out only during the growing season, and the rest of the time, WW enters the storage ponds.

Biological ponds are designed for deep cleaning of domestic and industrial wastewater, previously treated for VOCs. There are ponds with natural and artificial aeration (with the help of mechanical aerators), their depth is usually within 1-3 m. Aquatic vegetation plays an important role in oxidative processes, which helps to reduce the concentration of nutrients and regulates the oxygen regime of the reservoir.

Constructions of artificial biological treatment. Biological purification is based, as is known, on the process of biological oxidation. organic compounds contained in ST. Biological oxidation is carried out by a community of microorganisms (biocenosis), which includes many different bacteria, protozoa and a number of more highly organized organisms - algae, fungi and aphids, interconnected in a single complex by complex relationships (metabolism, symbiosis and antagonism).

Biofilters are widely used at daily consumption of household and industrial wastewater up to 20-30 thousand m3/day.

The biofilter is a tank that is filled with feed material (gravel, expanded clay, slag). Waste water is poured above the surface of the feed material; evenly over it is distributed through the feed material, on the surface of which a biological film (biocenosis) is formed, similar to activated sludge in an aerotank.

When operating biological treatment facilities, one should carefully observe the technological regulations for their work, avoid overloading and especially bursts of toxic components, significant deviations from the active reaction of the environment, since these violations can have a detrimental effect on the vital activity of microorganisms and disable biological oxidizers.

Disinfection of wastewater that has passed the stage of biological treatment, as well as those that have not passed it, is carried out with gaseous chlorine, bleach, and also sodium hypochlorite. In recent years, methods of disinfecting wastewater with the help of ozone and UV rays, as well as an electric pulse discharge, have been intensively introduced.

The place of wastewater discharge of the settlement should be located below its border along the watercourse. Discharge of sewage, waste and drainage waters within the boundaries of the settlement is allowed in exceptional cases on the basis of permits issued by the bodies for the protection of the environmental protection system and agreed with the bodies of state sanitary supervision.

Groundwater protection

The surface hydrosphere is inextricably linked with the atmosphere, underground hydrosphere, lithosphere, and other components of the OPS. Therefore, given the interconnection of all its ecosystems, it is impossible to ensure the purity of surface water bodies and watercourses without adequate protection of groundwater. The latter is to prevent the depletion of groundwater resources and protect them from pollution.

According to Art. 1 of the Water Code of the Russian Federation, groundwater is water, including mineral water, located in groundwater bodies. At the same time, groundwater and its host rocks recognized as a single water body.

In order to combat the depletion of fresh groundwater reserves, which are a strategic reserve for drinking water supply for future generations, the following measures are envisaged: 1) rational distribution of water intakes over the area; 2) regulation of the groundwater withdrawal regime; 3) clarification of the value of operational reserves (to prevent their depletion); 4) for self-flowing artesian wells, the establishment of a crane operating mode.

Sometimes, to prevent the depletion of groundwater, artificial replenishment is used by transferring part of the surface runoff into groundwater.

The fight against groundwater pollution includes preventive and special measures. Preventive measures are essential because they require the least cost. Special measures are aimed primarily at isolating sources of pollution from the rest of the aquifer (impervious walls, curtains), intercepting contaminated groundwater through drainage or pumping them out of special wells.

The most important preventive measure to prevent pollution of groundwater in areas of water intakes is the arrangement of sanitary protection zones around them.

Sanitary protection zones (SPZ) consist of three belts. The first belt includes an area at a distance of 30-50 m directly from the water intake (well). This is a strict regime zone, the presence of unauthorized persons and the performance of work not related to the operation of the water intake are prohibited in it. The second ZSZ belt serves to protect the aquifer from bacterial pollution, and the third - from chemical pollution. It is forbidden to place any objects that can cause this or that pollution, for example, livestock complexes. Logging, use of pesticides, etc. is not allowed.

The Ministry of Natural Resources of Russia in 1998 approved Guidelines on the development of standards for maximum permissible harmful effects (MAI) on groundwater bodies and maximum permissible discharges of harmful substances into groundwater bodies. MPE standards are a set of quantitative and qualitative indicators (characteristics) of processes and structures that can have a harmful effect on groundwater. If these standards are observed, the harmful effect does not exceed the permissible limits.

MPE standards are determined for each projected, under construction or operating object of economic activity in relation to a specific groundwater body, which may be affected by the specified activity.

Protection of small rivers

There are over 2.5 million small (up to 100 km long) rivers in Russia. They form almost half of the total volume of river runoff, up to 44% of the total urban population and almost 90% of the rural population live in their basins (Yu.V. Novikov, 1998).

Small rivers, being a kind of component of the geographic environment, act as a regulator of the water regime of certain landscapes, since they largely maintain balance and redistribute moisture. Let us add to this that they determine the hydrological and hydrochemical specificity of medium and large rivers.

Since the flow of small rivers is formed in close connection with the landscape of the basin, they are characterized by a high level of vulnerability, not only in case of excessive use of water resources, but also in the development of the watershed. Intensive economic activity causes especially great harm to small rivers. Because of this, they quickly overgrow and swamp, degrade and, in the end, disappear.

The protection of the waters of small rivers is closely connected with the protection from pollution of the territory from which the river collects its waters. Experts have calculated that more than 4,000 tons of organic matter, 6,000 tons of suspended solids, tens of tons of oil products enter the small rivers of the Vladimir Region every year, and more than 2,000 tons of ammonium nitrogen and 600 tons of nitrates are washed away from the fields by floods and rains.

Since the ability of small rivers to self-purify is significantly lower than that of large ones, it is important to create water protection zones on their banks and strictly maintain their regime. This zone (from 100 to 500 m wide) includes the floodplain, terraces above the floodplain, crests and steep bank slopes, ravines and gullies. It is recommended to arrange a device along the banks, strips of forest or meadows with a width of 15 to 100 m. Plowing slopes along the coast, grazing livestock, building livestock farms, and treating fields adjacent to rivers with pesticides is prohibited. The ravines adjacent to the water protection zone must be strengthened, the springs that feed the small river must be cleared.

Artificial aeration contributes to the increase in the ability of small rivers to process biochemically oxidized impurities that come with runoff and discharges of polluted waters. This is achieved by installing a dam with overflow, thanks to which the water falling even from a small height is well saturated with oxygen.

Industrial wastewater treatment

Methods for the treatment of industrial wastewater are divided into mechanical, chemical, physico-chemical and biological.

For mechanical cleaning, the following structures are used: gratings, on which coarse impurities larger than 5 mm in size are retained; sieves that retain impurities of CB up to 5 mm in size; sand traps used to trap mineral contaminants of the NE, mainly sand; grease traps, oil traps, oil traps, tar traps for trapping corresponding contaminants from waste water, which are lighter than water; settling tanks for settling suspended solids with a specific gravity greater than one.

The principle of operation of the sand trap is based on the fact that, under the influence of gravity, particles whose specific gravity is greater than the specific gravity of water, as they move along with water in the tank, settle to the bottom. In accordance with the laws of the hydraulics of the flow, grains of sand are carried away with water only at a certain flow rate. When this speed decreases, sand grains settle to the bottom of the tank, and the water flows further.

Sand traps are horizontal, in which water moves in a horizontal direction, vertical, in which water moves vertically upwards, and round, with a helical (translational-rotational) movement of water.

In the last sand traps, processes similar to those observed in a tea cup take place. When the tea poured into the cup is stirred, the tea leaves gather in the center of the cup. When the SW moves in a circular sand trap, large sand particles are similarly collected in its center. Through a hole in the center of the sand trap, they enter a special chamber.

During mechanical cleaning, up to 90% of insoluble mechanical impurities of various nature (sand, clay particles, scale, etc.) are removed from industrial wastewater by straining, settling and filtering, and up to 60% from household wastewater.

In order to clean wastewater from oil products, the settling method is also widely used, which in this case is based on the ability to spontaneously separate water and oil products. Particles of the latter under the action of forces surface tension acquire a spherical shape, and their sizes are in the range from 2 to 3102 microns. The settling process is based on the principle of separation of oil products under the influence of the difference in the densities of water and oil particles. The content of oil products in wastewater is within a wide range and averages 100 mg/l.

The separation of oil products is carried out in oil traps. Dirty water is supplied to the receiving chamber and, passing under the partition, enters the settling chamber, where the process of separation of water and oil products takes place. Purified water is removed from the oil trap, and oil products form a film on the surface of the water and are removed by a special device. Grease traps, oil traps and resin traps are similarly arranged, using the principle of the difference in density of water and contaminants that are lighter (for example, oil) than water.

Chemical methods are used to clean industrial wastewater. The main techniques are neutralization and oxidation-reduction, they can be used both as independent and as auxiliary in combination with others.

Industrial technological processes take place both in acidic (excess of H+ ions) and alkaline (excess of OH-) media, which leads to the appearance of the corresponding effluents. To balance the number of H+ and OH- ions - this is the essence of the neutralization method in wastewater treatment.

Rational is the mutual association of acidic and alkaline effluents. Disposal of acidic and alkaline wastewater through a single pipeline system is not always advisable, as this can cause precipitation in the pipes and, as a result, clog the network.

In order to neutralize acidic waters, alkaline reagents are used: lime CaO, hydrated lime Ca (OH) 2, soda ash Na2CO3, caustic soda NaOH, ammonia water, as well as filtration through neutralizing materials (limestone, dolomite, magnesite, chalk).

To neutralize alkaline waters, acids are most often used: sulfuric, hydrochloric, nitric, less often acetic. It is also possible to use flue gases containing CO2 SO2, NO2 for these purposes.

Wastewater containing oxidized variable-valent elements (Cr+6, Cl-, Cl+5, N-3, N+5, etc.) is neutralized in two stages. At the first stage, elements that are in the highest (or high) oxidation state are reduced to a lower (or intermediate) valence, at which this element can be separated from the liquid phase in the form of a precipitate, gas or transferred to a low-toxic form at the second stage of purification.

The oxidizing method is used in the purification of industrial wastewater from toxic cyanides, sulfides, mercaptans, phenols, cresols, etc. The reagents are chlorine and its derivatives (hypochlorites, dioxide, chlorates), oxygen, ozone, permanganates, chromates and dichromates, hydrogen peroxide. The recovery method is used to purify wastewater from nitrites and nitrates, chromates and dichromates, chlorates and perchlorates, sulfates, bromates, iodates. The reducing agents in this case are oxidized variable-valent elements contained in sulfites, sulfides, ferrous salts, sulfur dioxide (from flue gases).

Physico-chemical methods are also mainly used for the purification of industrial wastewater. However, recently some of them have been used in the purification of urban wastewater. These include, in particular, coagulation - the process of enlargement of colloidal particles in a liquid due to the electrostatic forces of intermolecular interaction. With an initial particle size of 0.001 - 0.1 µm after coagulation, their size reaches 10 µm or more, i.e. those sizes at which they can be isolated by mechanical methods. Coagulation not only leads to particles sticking together, but also violates the aggregative stability of the polydisperse system, resulting in the separation of solid and liquid phases.

A kind of coagulation is the process of flocculation - coarsening of fine particles due to electrostatic interaction under the influence of specially introduced polyelectrolytes - flocculants. In the practice of water treatment, activated silicic acid and polyacrylamide (PAA) are most widely used. The dose of coagulants and flocculants depends on the composition of the treated water and is specified during commissioning at the treatment plant.

Flotation is the process of separating suspended and emulsified contaminants from water into a foam layer as a result of adhering to gas bubbles supplied from below in the liquid to be purified.

Sorption is a method of deep purification of industrial wastewater from dissolved organic and some inorganic contaminants. In water treatment processes, it can be used both independently and in combination with other biological and chemical methods. Sorption makes it possible not only to isolate and concentrate contaminants from wastewater, but also to utilize them in the technological process, and to use purified water in circulating water supply.

The mechanism of adsorption consists in the transition of a solute molecule from the volume of liquid to the surface of a solid sorbent under the action of its force field. Various natural and artificial materials are used as sorbents: ash, coke breeze, peat, zeolites, active clays, etc. Activated carbons are especially widely used for these purposes, the specific adsorption surface reaches 400–900 m2/g.

For concentrated WW containing organic contaminants of technical value, extraction is an effective purification method. It is based on the mixing of two mutually insoluble liquids (one of which is waste water) and the distribution in them, according to the solubility, of the polluted substance.

Various organic substances are used as extractants: acetone, chloroform, butyl acetate, toluene, etc. The separation of the extractant and the extracted substance is carried out by distillation of the mixture. This determines one of the main requirements for choosing an extractant: different boiling points of the extractant and the substance to be separated. After separation of the mixture, the extractant is reused in the water treatment cycle, and the substance is disposed of.

Ion exchange is the extraction of cations and anions from contaminants dissolved in SW using ion exchangers, which are solid natural or artificial materials (for example, artificial ion exchange resins). Substances extracted by ion exchange are subsequently disposed of or destroyed. Cation exchangers exchange with cations, anion exchangers with anions.

Despite the efficiency and environmental friendliness, the ion-exchange method has not found wide application in industry due to the shortage of ion-exchange resins and the need to organize a reagent economy for the regeneration of ion exchangers.

The biological method described above is the most environmentally friendly of all methods. One of the basic principles of ecology - "nature knows best" - is implemented here by microbial communities by turning complex environmentally hazardous substances into simple, harmless ones.

Mastering waterless and drainless technologies

It is estimated that 1 m3 of untreated WW entering a natural water body can pollute hundreds of cubic meters of clean water, thereby creating unacceptable conditions for the life of hydrobionts. Therefore, technologies that either do not use water at all or do not form polluted effluents are promising. Their successful implementation into practice would completely solve the problem of protecting water bodies from pollution. Currently, in a number of chemical industries, for example, in the production of ammonia, synthetic methanol and other products, they switched from water cooling of high-temperature gas mixtures to air. Thus, the very acute issues of fresh water intake for industrial needs and the formation of polluted wastewater were removed.

Water supply technologies are also promising, which are characterized by minimal consumption of fresh water. With a closed technology, an enterprise takes water from a natural source, uses it to manufacture products, after which the resulting WW undergoes deep purification and returns to the cycle again. Any small losses of water, for example due to evaporation, are replenished by fresh water intake.

In a number of industries, closed water circulation schemes with local treatment have been partially implemented. Thus, in the petrochemical industry, circulating water supply saved 90% of industrial water.

Preparation of water for drinking purposes

The most important among water protection problems is the development of effective methods for preparing surface water for drinking purposes from an environmental and hygienic standpoint.

Pollution of natural sources of drinking water supply with insufficient efficiency of water treatment facilities entails a deterioration in the quality of water supplied to consumers. drinking water and creates a danger to public health in many regions of Russia, causes high level incidence intestinal infections, hepatitis, increases the risk of exposure to carcinogenic and mutagenic factors on the human body.

Every second inhabitant of our country is forced to use water for drinking purposes that does not meet hygienic requirements for a number of indicators; almost a third of the country's population uses decentralized water supply sources without adequate water treatment; the population of a number of regions suffers from a lack of drinking water and the lack of sanitary and living conditions associated with this. Russia's lagging behind developed countries in terms of average life expectancy and increased mortality (especially in children) are largely associated with the consumption of poor-quality water.

Measures for the protection of water resources can be classified similarly to measures for the protection of atmospheric air, highlighting active and passive measures.

Organizational measures belong to the group of passive ones. The need to develop these measures is due to the imperfection of the existing engineering and environmental equipment and technological production processes, which leads to a significant discharge of pollutants into water bodies. This group of measures prevents the local accumulation of pollution in water bodies and accelerates the dilution of wastewater. Organizational measures from an economic point of view are the cheapest. These include:

- organization of water protection zones;
- removal of the wastewater discharge point from the water intake point;
- dilution of wastewater,
- establishment of standards for the maximum allowable discharge of MPD, temporarily agreed discharge of VSS;
- economic restrictions(the payment for emissions within the MPD is calculated at the minimum rates and refers to the cost of production; payment for excess discharges is made from the free profit of the enterprise).

Technological measures for the protection of water bodies are classified as active, ensuring the prevention of pollution of the hydrosphere by reducing or eliminating discharges of pollutants. They are aimed at eliminating or mitigating the negative impacts of pollutants on environment. Technological measures include:

- reduction of water consumption;
- circulating and drainless water supply systems.

Engineering and environmental measures do not require a significant change in technology and are adapted to existing production and technological conditions, however, they are the most expensive. This group of activities includes wastewater treatment and sludge treatment by the following methods:

- mechanical methods(mechanical impurities are removed from wastewater by sedimentation and filtration, depending on the size of the particles they are caught by gratings and sieves of various designs, and surface contaminants - by oil traps, oil traps, etc.; the efficiency of the method is 60%);
- chemical methods(consist in the fact that chemical reagents are introduced into the drains that react with pollutants and contribute to their precipitation, neutralization of acids and alkalis is carried out in order to prevent corrosion of materials in drainage networks and treatment facilities using ozonation, chlorination);
- physical and chemical methods :
- coagulation (precipitation of pollutants - carried out with the help of coagulants, ammonium, iron, copper salts);
- sorption (introduction of substances capable of absorbing impurities, sorbents are: activated carbon, silica gel, bentonite clay);
- flotation (air is passed through wastewater, the bubbles of which, when moving upwards, capture chemically active substances into an easily removable foam).
- biological methods(removal of organic wastewater pollution with the help of microorganisms, for the implementation of this method there are several devices - biofilters, biological ponds, aerotanks, etc.).

Let's take a closer look at the above events.

In the Russian Federation, most of the water supply sources are surface (rivers, lakes, reservoirs). To maintain these sources in a state that meets environmental requirements, excludes pollution, clogging and depletion of surface waters and preserves the habitat of animals and plants, organize water protection zones . They are territories adjacent to the water area of rivers, reservoirs and other surface water bodies; they establish a special regime for the use and protection of natural resources, as well as the implementation of other activities. Within these zones, coastal protective strips are established, where it is not allowed to plow the land, cut down forests, place farms, etc.

Of great importance in the protection of surface waters from clogging and pollution are water-protective forest plantations. around natural and artificial reservoirs and streams. They are designed to protect them from the destructive effects of winds and water entering them from the catchment area, as well as to reduce water loss to evaporation. Forest plantations improve the water regime of reservoirs, the sanitary and hygienic conditions of the coast and its landscape and decorative design, the quality of water in reservoirs, reduce their siltation, and reduce the loss of land due to the processing of banks by waves (abrasion).

In addition to water protection zones, sanitary protection zones and districts may also be established to ensure water protection. They are established in order to protect water bodies used for drinking and domestic water supply, as well as containing natural healing resources.

In order to combat the depletion of fresh groundwater resources, which are a strategic reserve for the drinking water supply of future generations, the following measures are envisaged:

1) rational placement of water intakes over the area;
2) regulation of the groundwater withdrawal regime;
3) clarification of the value of operational reserves (to prevent their depletion);
4) for self-flowing artesian wells, the establishment of a crane operating mode.

The most important preventive measure to prevent pollution of groundwater in areas of water intakes is the arrangement of sanitary protection zones around them. Sanitary Protection Zones (SPZ) consist of three belts. The first belt includes an area at a distance of 30-50 m directly from the water intake (well). This is a strict regime zone, the presence of unauthorized persons and the performance of work not related to the operation of the water intake are prohibited in it. The second ZSZ belt serves to protect the aquifer from bacterial pollution, and the third - from chemical pollution. It is forbidden to place any objects that can cause this or that pollution, for example, livestock complexes. Logging, use of pesticides, etc. is not allowed.

The main mechanism for reducing the concentration of a pollutant when discharging wastewater into water bodies is dilution.

Wastewater dilution is the process of reducing the concentration of pollutants in water bodies, caused by the mixing of wastewater with the aquatic environment into which it is released.

The intensity of the dilution process is quantitatively characterized by the dilution factor n, which is equal to the ratio of the sum of wastewater costs q st, m 3 / s and the surrounding aquatic environment Q, m 3 / s wastewater consumption:

or the ratio of excess concentrations of pollutants at the point of release to similar concentrations in the considered section of the watercourse (total dilution at the site):

Where WITH st- concentration of pollutants in waste water, g/m 3 ; WITH f - the concentration of pollutants in water bodies before the release of wastewater, g / m 3; WITH is the concentration of pollutants in wastewater in the considered

To clean wastewater from large mechanical impurities in order to avoid clogging of pipes, channels and pumps of the hydraulic system, filtering is carried out. For this purpose, apply gratings And sieves with cells of various sizes depending on the nature of water pollution. Lattices are movable and fixed. Cleaning them from large particles is carried out using a special rake.

Settling tanks And sand traps designed for pre-treatment of wastewater from mineral and organic solid contaminants with relatively large particles (0.2-0.25 mm).

The scheme of the simplest sump is shown in fig. 9. The speed of water movement in the sump is low (0.3 m/s). The disadvantages of settling tanks are relatively low efficiency, low particle removal rate, large dimensions devices, a significant consumption of materials (metal, concrete) for their manufacture.

Floating harmful substances (oil, oils, resins, fats) are collected using oil traps, a feature of which is the removal of contaminants not from below, as in sedimentation tanks, but from the upper part of the apparatus. After oil traps (as well as after settling tanks), water needs additional purification, since these devices have a low degree of purification (about 70%).

Fig.9. Sump diagram

Filtration is used to remove small particles from wastewater. Water under pressure passes through porous partitions or a layer of sand. The diagram of the simplest mechanical filter is shown in fig. 10.

Rice. 10.

The filtering layer of the device must be washed from time to time from accumulated contaminants. To do this, wash water is fed into the filter from below. At a particle concentration of 15-20 mg/l, the degree of purification of fine particles reaches 60%. The disadvantages of the filters are the significant metal consumption and the complexity of the washing system.

The process of enlargement of small particles (1-100 microns) with their subsequent removal under the action of gravity is called coagulation. If particles are removed whose specific gravity is lower than the specific gravity of water (emulsified particles of oils, fat, etc.), then in this case the process is called flocculation. By analogy with the sump and oil trap in coagulators and flocculators, removal occurs respectively from the lower or upper part of the apparatus. During coagulation, coagulants (salts of aluminum, iron, or mixtures thereof) are added to the water, which form flakes of metal hydroxides that precipitate particles under the action of gravity. Starch, dextrin, ether, silicon dioxide are used as flocculants.

Flotation is used to remove particles that do not settle well, and for dissolved substances, including surfactants, waste from oil refining, artificial fiber production, pulp and paper production, etc.

Adsorption used for deep purification of wastewater from phenols, pesticides, aromatic compounds, dyes, etc. Adsorption is the adhesion of particles in the medium being cleaned to solid substances - sorbents. Activated carbons, synthetic sorbents, some production wastes (ash, slag, sawdust) are used as sorbents. The process takes place in adsorption plants when the adsorbent is mixed with water, when it is filtered through an adsorbent bed or in a fluidized bed.

Desorption, deodorization And degassing are the processes of wastewater treatment from volatile impurities (hydrogen sulfide, ammonia, carbon dioxide). These processes are carried out by purging water with air or an inert gas. Deodorization purifies water from mercaptans, amines, aldehydes; degassing removes corrosive substances from the water.

If there is an acid or alkali in the wastewater, they are produced neutralization, the pH should be between 6.5 and 8.5. Wastewater can be neutralized by mixing some waters with others (acidic with alkaline), adding the necessary reagents, filtering acidic waters through neutral materials, passing acidic gases through alkaline waters.

Oxidation wastewater is produced by chlorine, hydrogen peroxide, atmospheric oxygen, manganese dioxide, ozone.

Recovery used to remove mercury, chromium, arsenic compounds from wastewater, for which iron sulfite, sodium hydrosulfite, hydrazine, hydrogen sulfide or aluminum powder are introduced into the water.

Removal of heavy metal ions is carried out by the reagent method. Mercury, chromium, cadmium, zinc, lead, copper and nickel are removed using calcium and sodium hydroxides, sodium carbonates and sulfides, ferrochrome slag, etc.

Biological wastewater treatment methods are based on the ability of some microorganisms to use harmful (most often organic) substances for their nutrition in the process of life. Contacting with these substances, microbes partially destroy them, turning them into water, carbon dioxide, nitrite and sulfate ions, etc. Microorganisms are used in the form of activated sludge or biofilm. Biochemical wastewater treatment can be carried out in natural conditions (in irrigation fields, in biological ponds) or in artificial structures (aerotanks, biofilters).

Disinfection (disinfection) exposed to drains before descending into reservoirs. At the same time, pathogenic microbes and other bactericidal contaminants are destroyed, which reduces the likelihood of environmental risks in the aquatic environment. For disinfection, chlorination with gaseous chlorine or bleach is most widely used.

As a result of treatment, inorganic impurities present in it in the form of suspensions, dissolved and colloidal substances of various dispersions are removed from wastewater. The quality of cleaning is judged by the degree of water clarification and the content of harmful solutions, the concentration of which should be minimal. Solutions of heavy metals and chemically harmful substances are especially dangerous for the environment.

The protection of water resources consists in prohibiting the discharge of untreated water into reservoirs and streams, creating water protection zones, promoting self-purification processes in water bodies, maintaining and improving the conditions for the formation of surface and groundwater runoff in watersheds.

Several decades ago, rivers, thanks to their self-purifying function, coped with water purification. Now, in the most populated areas of the country, as a result of the construction of new cities and industrial enterprises, water use sites are located so densely that often places of wastewater discharge and water intakes are practically nearby. Therefore, the development and implementation of effective methods for the treatment and post-treatment of wastewater, purification and neutralization tap water is receiving more and more attention. In some enterprises, water related operations are playing an increasingly important role. Particularly high are the costs of water supply, treatment and disposal of wastewater in the pulp and paper, mining and petrochemical industries.

Sequential wastewater treatment at modern enterprises involves primary, mechanical treatment (easily settling and floating substances are removed) and secondary, biological (biologically degradable organic substances are removed). In this case, coagulation is carried out - for the precipitation of suspended and colloidal substances, as well as phosphorus, adsorption - in order to remove dissolved organic matter and electrolysis - to reduce the content of dissolved substances of organic and mineral origin. Disinfection of wastewater is carried out by means of their chlorination and ozonation. An important element of the technological process of cleaning is the removal and disinfection of the formed sludge. In some cases, the final operation is the distillation of water.

The most advanced modern treatment facilities ensure the release of wastewater from organic pollution only by 85-90%, and only in some cases - by 95%. Therefore, even after cleaning, it is necessary to dilute them 6-12-fold, and often even more with clean water to maintain the normal functioning of aquatic ecosystems. The fact is that the natural self-cleaning capacity of reservoirs and streams is very small. Self-purification occurs only if the discharged waters have been completely purified, and in the water body they have been diluted with water in a ratio of 1:12-15. If, however, large volumes of wastewater enter reservoirs and watercourses, and even more so untreated, the stable natural balance of aquatic ecosystems is gradually lost, and their normal functioning is disrupted.

Recently, more and more effective methods purification and post-treatment of wastewater after biological treatment using the latest methods of wastewater treatment: radiation, electrochemical, sorption, magnetic, etc. Improving the technology of wastewater treatment, further increasing the degree of purification are the most important tasks in the field of water protection from pollution.

Much more extensive use should be made of post-treatment of treated wastewater in agricultural irrigation fields. In the post-treatment of wastewater at the ZPO, funds are not spent on their industrial post-treatment, it creates the opportunity to receive additional agricultural products, water is significantly saved, since the intake of fresh water for irrigation is reduced and there is no need to spend water to dilute wastewater. When urban wastewater is used at the ZPO, the nutrients and microelements contained in it are absorbed by plants faster and more completely than artificial mineral fertilizers.

Prevention of pollution of water bodies with pesticides and pesticides is also one of the important tasks. This requires speeding up the implementation of anti-erosion measures, creating pesticides that would decompose within 1-3 weeks without preserving toxic residues in the culture. Until these issues are resolved, it is necessary to limit the agricultural use of coastal areas along watercourses or not to use pesticides in them. The creation of water protection zones also requires more attention.

In protecting water sources from pollution, the introduction of a fee for wastewater discharge, the creation of integrated regional schemes for water consumption, water disposal and wastewater treatment, and automation of water quality control in water sources are of great importance. It should be noted that integrated district schemes make it possible to switch to the reuse and reuse of water, the operation of treatment facilities common to the district, as well as to automate the processes of managing the operation of water supply and sewerage.

In preventing pollution of natural waters, the role of protecting the hydrosphere is important, since the negative properties acquired by the hydrosphere not only modify the aquatic ecosystem and depress its hydrobiological resources, but also destroy land ecosystems, its biological systems, and also the lithosphere.

It should be emphasized that one of the radical measures to combat pollution is to overcome the ingrained tradition of considering water bodies as wastewater receivers. Where possible, either water abstraction or wastewater discharge should be avoided in the same streams and reservoirs.

The hydrosphere includes all the water bodies of our planet, as well as groundwater, vapors and gases of the atmosphere, and glaciers. These sources are necessary for nature to sustain life. Now the quality of water has deteriorated significantly due to anthropogenic activities. Because of this, we are talking about many global problems of the hydrosphere:

chemical pollution of water;
pollution with garbage and waste;
destruction of flora and fauna living in water bodies;
oil pollution of water;

All these problems are caused by poor quality and insufficient amount of water on the planet. Despite the fact that most of the earth's surface, namely 70.8% is covered with water, not all people have enough drinking water. The fact is that the water of the seas and oceans is too salty and unsuitable for drinking. For this, water from fresh lakes and underground sources is used. Of the world's water reserves, only 1% is contained in fresh water. In theory, another 2% of the water that is in the solid state in glaciers is suitable for drinking if it is thawed and purified.

Water use in industry

The main problems of water resources are that they are widely used in industry: metallurgy and mechanical engineering, energy and food industry, in agriculture and the chemical industry. Used water is often no longer suitable for further use. Of course, when it is drained, enterprises do not purify it, so agricultural and industrial effluents enter the oceans.

One of the problems of water resources is its use in public utilities. Far from all countries people are provided with water supply, and pipelines leave much to be desired. As for the sewerage and drains, they directly merge into reservoirs without purification.

Relevance of water protection

To solve many problems, it is necessary to protect water resources. This is carried out at the state level, but ordinary people can also contribute:

reduce water consumption in industry;
rational use of water resources;
purify polluted water (industrial and domestic wastewater);
clean up water areas;
eliminate the consequences of accidents polluting water bodies;
save water in everyday use;
do not leave water taps open.

These are the actions to protect water that will help keep our blue planet (from water), and, therefore, will ensure the maintenance of life on earth.