One of the most valuable properties of natural waters is their ability to self-purify. Self-purification of waters is the restoration of their natural properties in rivers, lakes and other water bodies, occurring naturally as a result of interrelated physicochemical, biochemical and other processes (turbulent diffusion, oxidation, sorption, adsorption, etc.). The ability of rivers and lakes to self-cleanse is closely dependent on many other natural factors, in particular, physical and geographical conditions, solar radiation, the activity of microorganisms in water, the influence of aquatic vegetation, and especially the hydrometeorological regime. The most intensive self-purification of water in reservoirs and streams is carried out in the warm period of the year, when biological activity in aquatic ecosystems is the highest. It flows faster on rivers with a fast current and dense thickets of reeds, reeds and cattails along their banks, especially in the forest-steppe and steppe zones of the country. A complete change of water in rivers takes an average of 16 days, swamps - 5 years, lakes - 17 years.

Reducing the concentration of inorganic substances polluting water bodies occurs by neutralizing acids and alkalis due to the natural buffering of natural waters, the formation of sparingly soluble compounds, hydrolysis, sorption and sedimentation. The concentration of organic substances and their toxicity are reduced due to chemical and biochemical oxidation. These natural methods of self-purification are reflected in the accepted methods of purification of polluted waters in industry and agriculture.

To maintain the necessary natural water quality in reservoirs and streams, the distribution of aquatic vegetation, which plays the role of a kind of biofilter, is of great importance. The high cleansing power of aquatic plants is widely used in many industrial enterprises both in our country and abroad. For this, various artificial sedimentation tanks are created, in which lake and marsh vegetation is planted, which cleans polluted water well.

In recent years, artificial aeration has become widespread - one of the effective ways to purify polluted waters, when the self-purification process is sharply reduced when oxygen dissolved in water is deficient. To do this, special aerators are installed in reservoirs and streams or at aeration stations before the discharge of polluted water.

Protection of water resources from pollution.

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, preserving 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 of purification and post-treatment of wastewater, purification and neutralization of 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 - to precipitate suspended and colloidal substances, as well as phosphorus, adsorption - to remove dissolved organic substances 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 of purification and post-treatment of wastewater after their biological treatment have been developed and implemented using the latest methods of wastewater treatment: radiation, electrochemical, sorption, magnetic, etc. areas of protection of waters 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 district 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.

Protection of atmospheric air and soil.

Specially protected natural areas. Protection of flora and fauna.

effective form protection of natural ecosystems, as well as biotic communities are specially protected natural areas. They allow you to save standards (samples) of untouched biogeocenoses, and not only in some exotic, rare places, but also in all typical natural zones of the Earth.

TO specially protected natural areas(SPNA) includes areas of land or water surface, which, due to their environmental and other significance, are completely or partially withdrawn from economic use by decisions of the Government.

The Law on Protected Areas, adopted in February 1995, established the following categories of these territories: a) state nature reserves, incl. biospheric; b) national parks; c) natural parks; d) state nature reserves; e) monuments of nature; f) dendrological parks and botanical gardens.

Reserve- this is a space (territory or water area) specially protected by law, which is completely withdrawn from normal economic use in order to preserve the natural complex in its natural state. Only scientific, security and control activities are allowed in the reserves.

Today in Russia there are 95 nature reserves with a total area of ​​310 thousand square meters. km, which is about 1.5% of the entire territory of Russia. In order to neutralize the technogenic impact of the adjacent territories, especially in areas with developed industry, protected areas are created around the reserves.

Biosphere reserves (BR) perform four functions: the preservation of the genetic diversity of our planet; conducting scientific research; tracking the background state of the biosphere (environmental monitoring); environmental education and international cooperation.

Obviously, the functions of the BR are wider than the functions of any other type of protected natural areas. They serve as a kind of international standards, standards of the environment.

A unified global network of more than 300 biosphere reserves has now been created on Earth (11 in Russia). All of them work according to the coordinated program of UNESCO, conducting constant monitoring of changes in the natural environment under the influence of anthropogenic activities.

national park- a vast territory (from several thousand to several million hectares), which includes both fully protected areas and areas intended for certain types of economic activity.

The goals of creating national parks are: 1) environmental (preservation of natural ecosystems); 2) scientific (development and implementation of methods for preserving the natural complex in conditions of mass admission of visitors) and 3) recreational (regulated tourism and recreation for people).

There are 33 national parks in Russia with a total area of ​​about 66.5 thousand square meters. km.

Nature Park- a territory that has a special ecological and aesthetic value and is used for organized recreation of the population.

Reserve- is a natural complex, which is intended for the conservation of one or more species of animals or plants with limited use of others. There are landscape, forest, ichthyological (fish), ornithological (birds) and other types of reserves. Usually, after the restoration of the density of the population of protected species of animals or plants, the reserve is closed and one or another type of economic activity is allowed. In Russia today there are more than 1,600 state natural reserves with a total area of ​​over 600 thousand square meters. km.

natural monument- individual natural objects that are unique and irreproducible, having scientific, aesthetic, cultural or educational value. These can be very old trees that were “witnesses” to some historical events, caves, rocks, waterfalls, etc. There are about 8 thousand of them in Russia, while on the territory where the monument is located, any activity that can destroy them is prohibited .

Dendrological parks and botanical gardens are man-made collections of trees and shrubs in order to both preserve biodiversity and enrich the flora, and in the interests of science, study, and cultural and educational work. They often carry out work related to the introduction and acclimatization of new plants.

For violation of the regime of specially protected natural areas, Russian legislation establishes administrative and criminal liability. At the same time, scientists and experts strongly recommend a significant increase in the area of ​​specially protected areas. So, for example, in the United States, the area of ​​the latter is more than 7% of the country's territory.

The solution of environmental problems, and, consequently, the prospects for the sustainable development of civilization, is largely associated with the competent use of renewable resources and various functions of ecosystems, and their management. This direction is the most important way of a sufficiently long and relatively inexhaustible use of nature, combined with the preservation and maintenance of the stability of the biosphere, and, consequently, the human environment.

Each species is unique. It contains information about the development of flora and fauna, which is of great scientific and applied importance. Since all the possibilities of using a given organism in the long term are often unpredictable, the entire gene pool of our planet (with the possible exception of some pathogenic organisms dangerous to humans) is subject to strict protection. The need to protect the gene pool from the standpoint of the concept of sustainable development ("co-evolution") is dictated not so much by economic as by moral and ethical considerations. Humanity alone will not survive.

It is useful to recall one of B. Commoner's environmental laws: "Nature knows best!" Until recently, the possibilities of using the gene pool of animals that were unforeseen are now being demonstrated by bionics, thanks to which there are numerous improvements in engineering structures based on the study of the structure and functions of the organs of wild animals. It has been established that some invertebrates (mollusks, sponges) have the ability to accumulate a large amount of radioactive elements and pesticides. As a result, they can be bioindicators of environmental pollution and help humans solve this important problem.

Protection of the plant gene pool. Being an integral part of the general problem of protection of the PSO, the protection of the plant gene pool is a set of measures to preserve the entire species diversity of plants - carriers of the hereditary heritage of productive or scientifically or practically valuable properties.

It is known that under the influence of natural selection and through sexual reproduction of individuals in the gene pool of each species or population, the most useful properties for the species are accumulated; they are in gene combinations. Therefore, the tasks of using natural flora are of great importance. Our modern grain, fruit, vegetable, berry, fodder, industrial, ornamental crops, the centers of origin of which were established by our outstanding compatriot N.I. Vavilov, lead their genealogy either from wild ancestors, or are creations of science, but based on natural gene structures. By using the hereditary properties of wild plants, completely new types of useful plants have been obtained. Through hybrid selection, perennial wheat and grain fodder hybrids were created. According to scientists, about 600 species of wild plants can be used in the selection of agricultural crops from the flora of Russia.

The protection of the plant gene pool is carried out by creating reserves, natural parks, botanical gardens; formation of a gene pool of local and introduced species; study of biology, ecological needs and competitiveness of plants; ecological assessment of the plant habitat, forecasts of its changes in the future. Thanks to the reserves, Pitsunda and Eldar pines, pistachio, yew, boxwood, rhododendron, ginseng, etc. have been preserved.

Protection of the gene pool of animals. The change in living conditions under the influence of human activity, accompanied by direct persecution and extermination of animals, leads to the impoverishment of their species composition and a reduction in the number of many species. In 1600 there were approximately 4230 species of mammals on the planet, by our time 36 species have disappeared, and 120 species are in danger of extinction. Of the 8684 bird species, 94 have disappeared and 187 are endangered. The situation with subspecies is no better: since 1600, 64 subspecies of mammals and 164 subspecies of birds have disappeared, 223 subspecies of mammals and 287 subspecies of birds are endangered.

Protection of the human gene pool. For this, various scientific directions have been created, such as:

1) ecotoxicology- a branch of toxicology (the science of poisons), which studies the ingredient composition, features of distribution, biological action, activation, deactivation of harmful substances in the environment;

2) medical genetic counseling in special medical institutions to determine the nature and consequences of the action of ecotoxicants on the human genetic apparatus in order to give birth to healthy offspring;

3) screening- selection and testing for mutagenicity and carcinogenicity of environmental factors (human environment).

Environmental pathology- the doctrine of human diseases, in the occurrence and development of which the leading role is played by unfavorable environmental factors in combination with other pathogenic factors.

Principal directions of environmental protection.

Regulation of environmental quality. Protection of the atmosphere, hydrosphere, lithosphere, biotic communities. Eco-protection equipment and technologies.

Pollution entering the reservoir causes a violation of the natural balance in it. The ability of a reservoir to resist this disturbance, to get rid of the pollution introduced, is the essence of the self-purification process.

Self-purification of water systems is due to many natural and sometimes man-made factors. These factors include various hydrological, hydrochemical and hydrobiological processes. Conventionally, three types of self-purification can be distinguished: physical, chemical, biological.

Among physical processes, dilution (mixing) is of paramount importance. Good mixing and a reduction in the concentration of suspended particles is ensured by the intensive flow of rivers. Contributes to the self-purification of water bodies by settling polluted waters and settling to the bottom of insoluble sediments, sorption of pollutants by suspended particles and bottom sediments. For volatile substances, evaporation is an important process.

Among the chemical factors of self-purification of water bodies, the main role is played by the oxidation of organic and inorganic substances. Oxidation occurs in water with the participation of oxygen dissolved in it, therefore, the higher its content, the faster and better the process of mineralization of organic residues and self-purification of the reservoir proceeds. With severe pollution of the reservoir, the reserves of dissolved oxygen are quickly consumed, and its accumulation due to the physical processes of gas exchange with the atmosphere proceeds slowly, which slows down self-purification. Self-purification of water can also occur as a result of some other reactions in which hardly soluble, volatile or non-toxic substances are formed, for example, hydrolysis of pesticides, neutralization reactions, etc. Calcium and magnesium carbonates and bicarbonates contained in natural water neutralize acids, and carbonic acid dissolved in water neutralizes alkalis.

Under the influence of ultraviolet radiation of the sun in the surface layers of the reservoir, photodecomposition of some chemicals, such as DDT, and water disinfection occur - the death of pathogenic bacteria. The bactericidal action of ultraviolet rays is explained by their influence on the protoplasm and enzymes of microbial cells, which causes their death. Ultraviolet rays have a detrimental effect on vegetative forms of bacteria, fungal spores, protozoan cysts, and viruses.

Each body of water is a complex living system inhabited by bacteria, algae, higher aquatic plants, and various invertebrates. The processes of metabolism, bioconcentration, biodegradation lead to a change in the concentration of pollutants. Algae, molds and yeast fungi also belong to the biological factors of self-purification of a reservoir, however, in some cases, the mass development of blue-green algae in artificial reservoirs can be considered as a process of self-pollution. Representatives of the animal world can also contribute to the self-purification of water bodies from bacteria and viruses. So, oysters and some amoeba adsorb intestinal and other viruses. Each mollusk filters more than 30 liters of water per day. Common reed, narrow-leaved cattail, lake bulrush and other macrophytes are able to absorb from water not only relatively inert compounds, but also physiologically active substances such as phenols, poisonous salts of heavy metals.

The process of biological purification of water is associated with the content of oxygen in it. With a sufficient amount of oxygen, the activity of aerobic microorganisms that feed on organic substances is manifested. When organic matter is broken down, carbon dioxide and water are formed, as well as nitrates, sulfates, and phosphates. Biological self-purification is the main link in the process and is considered as one of the manifestations of the biotic cycle in a reservoir.

The contribution of individual processes to the ability of the natural aquatic environment to self-purify depends on the nature of the pollutant. For the so-called conservative substances that do not decompose or decompose very slowly (metal ions, mineral salts, persistent organochlorine pesticides, radionuclides, etc.), self-purification has an apparent character, since only the redistribution and dispersion of the pollutant in the environment occurs, pollution adjacent objects to them. The decrease in their concentration in water occurs due to dilution, removal, sorption, bioaccumulation. With regard to biogenic substances, biochemical processes are most important. For water-soluble substances that are not involved in the biological cycle, the reactions of their chemical and microbiological transformation are important.

For most organic compounds and some inorganic substances, microbiological transformation is considered one of the main ways of self-purification of the natural aquatic environment. Microbiological biochemical processes include reactions of several types. These are reactions involving redox and hydrolytic enzymes (oxidases, oxygenases, dehydrogenases, hydrolases, etc.). Biochemical self-purification of water bodies depends on many factors, among which the most important are temperature, active reaction of the environment (pH), and the content of nitrogen and phosphorus. The optimum temperature for biodegradation processes is 25-30ºС. Of great importance for the vital activity of microorganisms is the reaction of the environment, which affects the course of enzymatic processes in the cell, as well as changes in the degree of penetration of nutrients into the cell. For most bacteria, a neutral or slightly alkaline reaction of the medium is favorable. At pH<6 развитие и жизнедеятельность микробов чаще всего снижается, при рН <4 в некоторых случаях их жизнедеятельность прекращается. То же самое наблюдается при повышении щелочности среды до рН>9,5.

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MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION

FEDERAL AGENCY FOR EDUCATION AND SCIENCE

MARI STATE TECHNICAL UNIVERSITY

Department of environmental management

Course work

discipline: Ecological bases of environmental impact assessment

on the topic of: Patterns of selfwater purification in water bodies

Completed: Art. gr. PO-41 Konakova M.E.

Checked by: Associate Professor Khvastunov A.I.

Yoshkar-Ola

Introduction

1 Concept, stages of environmental impact assessment

1.1 The concept of EIA

1.2 Stages of the environmental impact assessment procedure

1.3 Assessment of impacts on surface waters

2 Sources of information when drawing up the terms of reference for the EIA

3 Indicators for evaluating the effectiveness of treatment facilities

4 Sources of pollution of a water body depending on the landscape structure of the area

5 Main processes of water self-purification in a water body

6 Measures to intensify the processes of self-purification of a water body

Conclusion

Bibliography

Introduction

At all times, water was considered the priceless moisture of life. And although those years are far behind when it was necessary to take it in rivers, ponds, lakes and carry it several kilometers to the house on yokes, trying not to spill a single drop, a person still treats water with care, taking care of the cleanliness of natural reservoirs, of good condition of wells, columns, plumbing systems. In connection with the ever-growing needs of industry and agriculture for fresh water, the problem of preserving existing water resources is becoming increasingly acute. After all, water suitable for human needs, as statistics show, is not so much on the globe. It is known that more than 70% of the Earth's surface is covered with water. About 95% of it falls on the seas and oceans, 4% on the ice of the Arctic and Antarctic, and only 1% is fresh water of rivers and lakes. Significant sources of water are underground, sometimes at great depths.

The 20th century is characterized by an intensive growth of the world's population and the development of urbanization. Giant cities with a population of more than 10 million people appeared. The development of industry, transport, energy, industrialization of agriculture have led to the fact that the anthropogenic impact on the environment has assumed a global character. Increasing the effectiveness of measures to protect the environment is associated primarily with the widespread introduction of resource-saving, low-waste and non-waste technological processes, and a decrease in air and water pollution.

Environmental protection is a very multifaceted problem, which is addressed, in particular, by engineering and technical workers of almost all specialties that are associated with economic activities in settlements and industrial enterprises, which can be a source of pollution mainly of air and water.

The United Nations Organization in the Declaration of the Conference on Environment and Development (Rio de Janeiro, June 1992), which our country also signed, defined the general principles of the legal approach to nature protection; pointed out that all states should have tough and at the same time reasonable environmental legislation. At present, a system of legal protection of nature has been created in Russia, which is a set of legal norms established by the state and legal relations arising as a result of their implementation, aimed at implementing measures to preserve the natural environment, rational use of natural resources, improve the living environment surrounding a person in the interests of the present and future generations.

One of the mechanisms for implementing the legal protection of nature is the environmental impact assessment, which is the most effective managerial lever for rational nature management and environmental protection, which ultimately should solve the environmental problems of Russia.

In the Federal Law "On Environmental Protection" dated January 10, 2002, Chapter VI (Art. 32, 33) is devoted to environmental impact assessment and environmental expertise. These procedures are a mandatory measure in relation to planned economic or other activities that can have a direct or indirect impact on the environment, regardless of the form of ownership and departmental affiliation of the subjects of this activity. Environmental impact assessment and environmental expertise are interrelated elements of a single legal institution - impact assessment and environmental expertise.

1 Concept, stages of environmental impact assessment

1 . 1 The concept of EIA

So far, the only valid Russian regulatory document regulating the environmental impact assessment (EIA) _ Regulation "On environmental impact assessment in the Russian Federation" (approved by order of the Ministry of Natural Resources of Russia dated July 18, 1994 No. 222), determined the environmental impact assessment environment as "a procedure for taking into account the environmental requirements of the legislation of the Russian Federation in the preparation and adoption of decisions on the socio-economic development of society in order to identify and take necessary and sufficient measures to prevent possible environmental and related social, economic and other consequences of the implementation of an economic or other activities".

At first glance, concepts similar to each other have some semantic differences.

EIA _ is a "procedure for taking into account" environmental requirements (or justification _ informational measure) in the preparation of the optimal solution (during the design).

EIA is inherently a process of studying the impact of a proposed activity and predicting its consequences for the environment and human health.

The purpose of the EIA is to identify and adopt (ie develop) the necessary environmental measures.

The results of the EIA are part of the documentation submitted for environmental review. They are formed by: information on the scale and nature of the impact on the environment of the planned activity, alternatives for its implementation, assessment of the actual consequences of the activity, etc. They also serve as the basis for monitoring and environmental control over the activities being implemented.

The tasks of EIA in the current Russian legislation are still practically not disclosed, but in general they can be formulated as follows: organization and conduct (at the stage of preparing a decision) comprehensive, objective, scientific research and analysis of objects of expertise from the standpoint of efficiency, completeness, the validity and sufficiency of the measures provided for in them, the correctness of the customer's determination of the degree of environmental risk and danger of the planned or ongoing activities, as well as the provision of environmental forecasting based on information about the state and possible changes in the environmental situation due to the location and development of productive forces that do not lead to a negative impact on environment (OS), i.e. determining the likelihood of environmentally harmful impacts and possible social, economic and environmental consequences.

1 . 2 Stages of the environmental impact assessment procedure

The Regulations on the assessment of the impact of planned economic and other activities on the environment in the Russian Federation, approved by the order of the State Committee for Ecology of Russia dated May 16, 2000 No. 372, provide for the following stages of the assessment:

1. Notification, preliminary assessment and preparation of terms of reference for the EIA.

2. Conducting studies on the EIA of the planned economic and other activities and preparing a preliminary version of the relevant materials.

3. Preparation of the final version of the EIA materials. The principles, procedure and other information about the EIA are described in detail in the regulatory documents and literature.

3.1. Notification, preliminary assessment and preparation of terms of reference for the EIA

The first stage of the EIA begins simultaneously with the development of the concept of the proposed activity.

During the EIA process, the following tasks are solved at this stage:

1. Identification of the possibility of additional anthropogenic load on the environment of a given territory.

2. Determination of the permissible scale of involvement in the processing of natural resources and energy in a given territory.

3. Consideration of alternative ways to improve the environmental situation, including by reducing the technogenic load of other sources of impact.

4. Formation of project proposals for the implementation of planned activities.

5. Preparation of terms of reference for the assessment of the established content.

The basis for the development of the concept of the planned activity can be the schemes for the placement and development of productive forces, the schemes for the placement and development of industries and other documents replacing them.

At the stage of developing the concept of the planned activity, the possibilities of achieving the indicators defined in these documents in relation to a specific object are taken into account, the issues of the possibility of influencing the environment are worked out in more detail, taking into account the dynamics of the actual environmental situation in the region.

The necessity and expediency of implementing the design concept with the identification, analysis and evaluation of real alternatives for the development of activities in the given territory is substantiated.

The concept necessarily evaluates alternative sources of raw materials and energy, secondary raw materials and energy resources and production waste, and searches for new areas of application for the waste of the future facility.

Another key issue of the concept is to ensure environmental safety, including solving the problems of localization and elimination of the consequences of accidents and disasters.

The concept should provide for an assessment of the technological level of the project and exclude technological solutions that may become obsolete by the time the construction of the facility is completed.

When developing the concept of planned activities, special attention is paid to assessing the progressiveness of solutions, taking into account possible changes in technical and economic indicators, tightening industry environmental standards for environmental impact, changes in resource prices and environmental pollution charges.

Thus, the EIA begins when the customer of the planned activity forms a proposal for the implementation of a project or program (the concept of the proposed activity). Based on the results of this stage, the customer prepares a "Notice of Intent", which contains:

1) a preliminary list of the customer’s intentions by the nature of the planned activity, including plans for proposed actions, a preliminary assessment of the impact on the environment and the implementation of environmental measures, the specifics of the annual plans for these works, a list of infrastructure facilities, etc.;

2) a list of real and feasible alternatives to the project under consideration (one of the alternatives is necessarily the option of abandoning the activity).

Based on the results of the preliminary EIA, the customer draws up the terms of reference for the EIA.

When drawing up the terms of reference, the customer takes into account the requirements of specially authorized bodies for the protection of the environment, as well as the opinions of other participants in the process at their request; it is available to the public at all times during the assessment. The assignment is part of the EIA materials.

Local authorities and administrations, after receiving and considering the "Notice of Intent" from the customer, issue (or do not issue) him a permit for design and survey.

3.2. Conducting EIA studies and preparing a preliminary version of the relevant materials

The purpose of the second stage of the EIA is to identify all possible impacts of the future economic or other object on the environment, taking into account the natural conditions of a particular area. Research is carried out by the customer (executor) in accordance with the terms of reference, taking into account alternatives for implementation, goals of the activity, ways to achieve them.

The second stage of the EIA is a systematic, reasonable assessment of the environmental aspects of the project proposal based on the use of complete and reliable initial information, means and methods of measurement, calculations, estimates in accordance with the legislation of the Russian Federation,

The study includes determining the characteristics of the planned economic and other activities and possible alternatives (including the abandonment of activities); analysis of the state of the territory, which may be affected by the proposed activity (the state of the natural environment, the presence and nature of anthropogenic load, etc.); identification of possible impacts of the proposed activity on the environment, taking into account alternatives; assessment of environmental impacts of activities (probability of risk occurrence, degree, nature, scale, distribution area, as well as forecasting environmental and related social and economic consequences); determination of measures that reduce, mitigate or prevent negative impacts, assessment of their effectiveness and feasibility; assessment of the significance of residual impacts on the environment and their consequences; preparation of a preliminary version of materials on environmental impact assessment of the proposed activity (including a summary for non-specialists) and a number of other issues.

3.3. Preparation of the final version of the EIA materials

The purpose of the third stage of the EIA is to correct projects that have passed the EIA stage. The approach suggested for use at this stage is to make decisions step by step:

1) for projects that do not require additional scientific research;

2) for projects requiring only minor research;

3) for complex and complex project proposals that require the involvement of extensive scientific research.

Many project proposals can be considered by analogy with those already taking place in the selected area or in an area with similar natural conditions. In such cases, methods of peer review and analogies are used. The preliminary version of the materials is analyzed and comments, suggestions and information received from the participants in the evaluation process at the discussion stage are taken into account. The final version of the evaluation materials should also include the minutes of public hearings (if any).

The Environmental Impact Statement (EPS) is considered as a report by the developer of project documentation on the work done on the EIA of the proposed activity and is submitted by the customer as part of the project documentation. The ZEP is drawn up as a separate document and includes:

1) title page;

2) a list of organizations and specific developers involved in the EIA:

work manager, coordinator,

specialists responsible for the sections,

specialists responsible for environmental and socio-economic sections;

3) the main sections of research carried out at all stages of the EIA:

the purpose and necessity of the implementation of the planned activity,

technological analysis of project proposals, analysis of the natural conditions of the territories and the existing technogenic load,

analysis and assessment of sources and types of impact, identification of especially significant public positions, forecast of environmental changes in environmentally significant positions;

4) conclusions drawn on the basis of scientific research, surveys and public hearings of the EIS;

5) environmental consequences of the impact on the environment, the health of the population and its livelihoods;

6) the obligations of the customer to implement the measures and activities set out in the design documentation in accordance with environmental safety and guarantee the fulfillment of these obligations for the entire life cycle of the facility.

The EPZ is transferred by the customer to all interested parties participating in the discussion of the EIA, namely:

state authorities, management and control;

the public and interested parties who exercise control over the fulfillment of the obligations assumed by the customer when deciding on the implementation of the planned activity.

The final version of the materials is approved by the customer, is used in the preparation of the relevant documentation and, thus, is submitted to the state, as well as to the public.

1. 3 Assessment of impact on surface waters

Assessment of the state of surface waters has two aspects: quantitative and qualitative. Both aspects constitute one of the most important conditions for the existence of living beings, including humans.

Surface water quality assessment is relatively well developed and based on legislative, regulatory and policy documents.

The fundamental law in this area is the Water Code of the Russian Federation; sanitary and epidemiological requirements for water bodies are determined by Art. 18 of the Federal Law "On the sanitary and epidemiological well-being of the population". Regulatory and directive documents include: Decree of the Government of the Russian Federation of December 19, 1996 No. 1504 "On the procedure and approval of standards for the maximum permissible harmful effects of MPE on water bodies"; Guidelines for the development of MPD standards for harmful substances into surface water bodies, approved by order of the Ministry of Natural Resources of Russia on December 17, 1998; Methodological guidelines for the development of MPE standards for surface water bodies, approved by the Russian Ministry of Natural Resources, the Russian State Committee for Ecology on February 26, 1999, Methodological guidelines for the development of MPE standards for groundwater bodies and MPDs for harmful substances in groundwater bodies, approved by the Russian Ministry of Natural Resources on December 29, 1998 ; Sanitary rules and norms for the protection of surface waters from pollution (1988), as well as existing standards.

Assessing the quantitative aspects of water resources (including their pollution) has a dual purpose. Firstly, it is necessary to assess the possibilities of meeting the needs of the planned activity in water resources, and secondly, the consequences of a possible withdrawal of the remaining resources for other facilities and the life of the population.

For such assessments, it is necessary to have data on the hydrological features and patterns of the regime of water bodies that are sources of water supply, as well as the existing levels of consumption and volumes of water resources required for the implementation of the project.

The latter also includes the technological scheme of water consumption (irreversible, reverse, seasonal, etc.) and is an assessment of the direct impact of the planned activity on the amount of water resources.

However, the indirect impact, which ultimately affects the hydrological characteristics of water bodies, is also of great importance. Indirect impacts include disturbance of the river bed (by dredges, dredgers, etc.), changes in the surface of the catchment area (plowing of land, deforestation), springing (flooding) during construction or lowering of groundwater, and much more. It is necessary to identify and analyze all possible types of impacts and their consequences for assessing the state of water resources.

Two most capacious indicators are recommended as criteria for assessing surface water resources: the value of surface (river) runoff or changes in its regime in relation to a particular basin and the value of the volume of one-time water withdrawal.

The most common and significant factor causing the shortage of water resources is the pollution of water sources, which is usually judged from the observational data of the monitoring services of Roshydromet and other departments that control the state of the aquatic environment.

Each water body has its own natural hydrochemical quality, which is its initial property, which is formed under the influence of hydrological and hydrochemical processes occurring in the reservoir, as well as depending on the intensity of its external pollution. The cumulative impact of these processes can both neutralize the harmful effects of anthropogenic pollution entering water bodies (self-purification of water bodies) and lead to a persistent deterioration in the quality of water resources (pollution, clogging, depletion).

The self-purification ability of each water body, i.e. the amount of pollutants that can be processed and neutralized by a water body, depends on various factors and obeys certain patterns (the incoming amount of water diluting polluted effluents, its temperature, changes in these indicators over the seasons, the qualitative composition of pollutants ingredients, etc.).

One of the main factors determining the possible levels of pollution of water bodies, in addition to their natural properties, is the initial hydrochemical state that occurs under the influence of anthropogenic activity.

Predictive estimates of the state of pollution of water bodies can be obtained by summing up the existing levels of pollution and additional quantities of pollutants planned for the intake of the designed facility. In this case, it is necessary to take into account both direct (direct discharge into water bodies) and indirect (surface runoff, subsoil runoff, aerogenic pollution, etc.) sources.

The main criterion for water pollution is also MPC, among which there are sanitary and hygienic (normalized according to the effect on the human body), and fisheries, developed to protect hydrobionts (living creatures of water bodies). The latter, as a rule, are stricter, since the inhabitants of water bodies are usually more sensitive to pollution than humans.

Accordingly, reservoirs are divided into two categories: 1) drinking and cultural purposes; 2) for fishery purposes. In water bodies of the first type, the composition and properties of water must comply with the standards in sites located at a distance of 1 km from the nearest water use point. In fishery reservoirs, water quality indicators should not exceed the established standards at the place of wastewater discharge in the presence of a current, in its absence - no further than 500 m from the place of discharge.

The main source of information about the hydrological and hydrochemical properties of water bodies are the materials of observations carried out in the network of the Unified State System for Environmental Monitoring (Unified State System of Environmental Monitoring) of Russia.

An important place among the criteria for environmental assessment of the state of water bodies is occupied by indicative assessment criteria. Recently, bioindication (along with traditional chemical and physicochemical methods) has become quite widespread in assessing the quality of surface waters. According to the functional state (behavior) of the test objects (crustaceans - daphnia, algae - chlorella, fish - guppies), it is possible to rank the waters according to the classes of states and, in essence, give an integral assessment of their quality, as well as determine the possibility of using water for drinking and other related purposes. biota, goals. The limiting factor in the use of the biotesting method is the duration of the analysis (at least 4 days) and the lack of information about the chemical composition of water.

It should be noted that due to the complexity and diversity of the chemical composition of natural waters, as well as the increasing number of pollutants (more than 1625 harmful substances for drinking and cultural water bodies, more than 1050 for fishery water bodies), methods have been developed for a comprehensive assessment of contamination of surface waters, which are fundamentally divided into two groups.

The first includes methods that allow assessing the quality of water by a combination of hydrochemical, hydrophysical, hydrobiological, microbiological indicators.

Water quality is divided into classes with varying degrees of contamination. However, the same state of water according to different indicators can be assigned to different quality classes, which is a disadvantage of these methods.

The second group consists of methods based on the use of generalized numerical characteristics of water quality, determined by a number of basic indicators and types of water use. Such characteristics are water quality indices, coefficients of its pollution.

In hydrochemical practice, the water quality assessment method developed at the Hydrochemical Institute is used. The method allows for an unambiguous assessment of water quality based on a combination of the level of water pollution in terms of the totality of pollutants present in it and the frequency of their detection.

Based on the material provided and taking into account the recommendations set out in the relevant literature, when conducting an impact assessment on surface waters, it is necessary to study, analyze and document the following:

1) hydrographic characteristics of the territory;

2) characteristics of water supply sources, their economic use;

3) assessment of the possibility of water intake from a surface source for production needs in natural conditions (without regulation of river flow; taking into account the existing regulation of river flow);

4) the location of the water intake, its characteristics;

5) characteristics of the water body in the design section of the water intake (hydrological, hydrochemical, ice, thermal, high-speed regimes of water flow, sediment regime, channel processes, dangerous phenomena: congestion, the presence of sludge);

6) organization of a sanitary protection zone of water intake;

7) water consumption during the construction of the facility, the water management balance of the enterprise, assessment of the rationality of water use;

8) wastewater characteristics - flow rate, temperature, composition and concentrations of pollutants;

9) technical solutions for wastewater treatment during the construction of the facility and its operation - a brief description of treatment facilities and installations (technological scheme, type, performance, main design parameters), expected treatment efficiency;

10) reuse of water, recycling water supply;

11) methods of disposal of sewage treatment plant sludge;

12) wastewater discharge - the place of discharge, design features of the outlet, the mode of disposal of wastewater (frequency of discharges);

13) calculation of MPD of treated wastewater;

14) characteristics of residual pollution during the implementation of measures for wastewater treatment (in accordance with the MPD);

15) assessment of changes in surface runoff (liquid and solid) as a result of redevelopment of the territory and removal of the vegetation layer, identification of the negative consequences of these changes on the water regime of the territory;

16) assessment of the impact on surface water during construction and operation, including the consequences of the impact of water withdrawal on the ecosystem of the reservoir; thermal, chemical, biological pollution, including during accidents;

17) assessment of changes in channel processes associated with the laying of linear structures, construction of bridges, water intakes and identification of the negative consequences of this impact, including on hydrobionts;

18) forecast of the impact of the planned facility (water withdrawal, residual pollution from the discharge of treated wastewater, changes in temperature, etc.) on aquatic flora and fauna, on the economic and recreational use of water bodies, living conditions of the population;

19) organization of control over the state of water bodies;

20) the volume and total cost of water protection measures, their effectiveness and the order of implementation, including measures to prevent and eliminate the consequences of accidents.

2 Sources of information when drawing up the terms of reference for the EIA

Public information and participation is carried out at all stages of the EIA. Public participation in the preparation and discussion of environmental impact assessment materials is provided by the customer, organized by local governments or relevant state authorities with the assistance of the customer.

Informing the public and other participants in the EIA at the first stage is carried out by the customer. The customer ensures that the following information is published in the official publications of the federal executive authorities (for objects of expertise at the federal level), executive authorities of the constituent entities of the Russian Federation and local governments, on the territory of which the implementation of the EIA object is planned: the name, objectives and location of the planned activity; name and address of the customer or his representative; approximate timing of the EIA; body responsible for organizing public discussion; the intended form of public discussion, as well as the form for submitting comments and suggestions; terms and place of availability of the terms of reference for environmental impact assessment. Additional information to participants in the EIA can be carried out by distributing information on radio, on television, in periodicals, via the Internet and in other ways.

Within 30 days from the date of publication of information, the customer (executor) accepts and documents comments and suggestions from the public. These comments and suggestions are taken into account when drawing up the terms of reference and should be reflected in the EIA materials. The client is obliged to provide access to the terms of reference to the public concerned and other participants in the EIA from the moment of its approval until the end of the EIA process.

After the preparation of the preliminary version of the environmental impact assessment materials, the contracting authority must provide the public with information about the timing and place of availability of the preliminary version, as well as the date and place of public discussions. This information is published in the media no later than 30 days before the end of the public discussions. Submission of a preliminary version of materials on environmental impact assessment to the public for review and submission of comments is made within 30 days, but no later than 2 weeks before the end of public discussions (public hearings).

Public discussions can be held in various forms: a survey, public hearings, a referendum, etc. When deciding on the form of holding public discussions, it is necessary to be guided by the degree of environmental hazard of the planned economic and other activities, take into account the uncertainty factor, the degree of public interest.

The procedure for conducting public hearings is determined by local governments with the participation of the customer (executor) and the assistance of the public concerned. All decisions on public participation are documented - by drawing up a protocol. It should clearly record the main issues of discussion, as well as the subject of disagreement between the public and the customer (if any). The protocol is signed by representatives of executive authorities and local self-government, citizens, public organizations (associations), the customer. The protocol of the public hearings is included as one of the appendices in the final version of the materials on the environmental impact assessment of the planned economic and other activities.

From the moment the final version of the EIA materials is approved and until a decision is made on the implementation of the proposed activity, the customer provides public access to these materials. Citizens and public organizations can send their proposals and comments on them to the customer, who ensures their documentation within 30 days after the end of the public discussion. Subsequently, proposals and comments may be sent to a specially authorized state body in the field of conducting state environmental expertise.

Requirements for environmental impact assessment materials Impact assessment materials are a set of documentation prepared during the environmental impact assessment of the proposed activity and being part of the documentation submitted for environmental expertise.

3 Indicators for evaluating the effectiveness of treatment facilities

Wastewater - these are waters used for domestic, industrial or other needs and contaminated with various impurities that have changed their original chemical composition and physical properties, as well as water flowing from the territory of settlements and industrial enterprises as a result of precipitation or watering streets. Depending on the origin of the type and composition, wastewater is divided into three main categories:

household(from toilet rooms, showers, kitchens, baths, laundries, canteens, hospitals; they come from residential and public buildings, as well as from domestic premises and industrial enterprises);

Production(waters used in technological processes that no longer meet the requirements for their quality; this category of waters includes waters pumped to the surface of the earth during mining);

atmospheric(rain and melt; along with atmospheric water, water is drained from street irrigation, from fountains and drains).

In practice, the concept is also used municipal wastewater, which are a mixture of domestic and industrial wastewater. Household, industrial and atmospheric wastewater is discharged both jointly and separately.

Wastewater is a complex heterogeneous mixture containing impurities of organic and mineral origin, which are in an undissolved, colloidal and dissolved state.

Some of the parameters, the definition of which is provided for by the mandatory program of observations for water quality:

Chroma- this is an indicator of water quality, characterizing the intensity of water color and due to the content of colored compounds, which is expressed in degrees of the platinum-cobalt scale. It is determined by comparing the color of the test water with standards.

Transparency (light transmission) due to their color and turbidity, i.e. the content in them of various colored and suspended organic and mineral substances.

Depending on the degree of transparency, water is conditionally divided into transparent, slightly opalescent, opalescent, slightly turbid, turbid and highly turbid.

Turbidity- caused by the presence of finely dispersed impurities caused by insoluble or colloidal inorganic and organic substances of various origins. Qualitative determination is carried out descriptively: weak opalescence, opalescence, weak, noticeable and strong turbidity.

Smell- this is the property of water to cause specific irritation of the mucous membrane of the nasal passages in humans and animals. The smell of water is characterized by intensity, which is measured in points. The smell of water is caused by volatile odorous substances entering the water as a result of the vital processes of aquatic organisms, during the biochemical decomposition of organic substances, during the chemical interaction of the components contained in the water, as well as with industrial, agricultural, household wastewater.

suspended solids affect the transparency of water and the penetration of light into it, the temperature, the composition of dissolved components of surface water, the adsorption of toxic substances, as well as the composition and distribution of sediments and the rate of sedimentation.

It is important to determine the amount of suspended particles when monitoring the processes of biological and physico-chemical treatment of wastewater and when assessing the state of natural water bodies.

Hydrogen indicator is one of the most important indicators of water quality. The concentration of hydrogen ions is of great importance for chemical and biological processes. The development and vital activity of aquatic plants, the stability of various forms of element migration, the aggressive effect of water on metals and concrete depend on the pH value. The pH value of water also affects the processes of transformation of various forms of biogenic elements, changes the toxicity of pollutants.

Redox potential- a measure of the chemical activity of elements or their compounds in reversible chemical processes associated with a change in the charge of ions in solutions.

chlorides- the predominant anion in highly mineralized waters. The concentration of chlorides in surface waters is subject to noticeable seasonal fluctuations, which correlate with changes in the total salinity of the water.

Nitrogen ammonium salts- the content of ammonium ions in natural waters varies from 10 to 200 µg/dm 3 in terms of nitrogen. The presence of ammonium ions in unpolluted surface waters is mainly associated with the processes of biochemical degradation of protein substances, deamination of amino acids, and decomposition of urea under the action of urease. The main sources of ammonium ions in water bodies are livestock farms, domestic wastewater, surface runoff from farmland when using ammonium fertilizers, and wastewater from food, wood chemical and chemical industries.

An increased concentration of ammonium ions can be used as an indicator reflecting the deterioration of the sanitary condition of a water body, the process of pollution of surface and ground waters, primarily by domestic and agricultural effluents.

MPC BP of salt ammonium is 0.4 mg/l for nitrogen (the limiting indicator of harmfulness is toxicological).

Nitrates- the main processes aimed at lowering the concentration of nitrates are their consumption by phytoplankton and denitrifying bacteria, which, in the absence of oxygen, use the oxygen of nitrates for the oxidation of organic substances.

In surface waters, nitrates are in dissolved form. The concentration of nitrates in surface waters is subject to noticeable seasonal fluctuations: it is minimal during the growing season, it increases in autumn and reaches a maximum in winter, when organic forms are decomposed into mineral ones with minimal nitrogen consumption. The amplitude of seasonal fluctuations can serve as one of the indicators of eutrophication of a water body.

MPC vr - 40 mg/l (according to NO3-) or 9.1 mg/l (according to nitrogen).

Nitrites- represent an intermediate step in the chain of bacterial processes of ammonium oxidation to nitrates and, on the contrary, reduction of nitrates to nitrogen and ammonia. Similar redox reactions are typical for aeration stations, water supply systems and natural waters themselves.

MPC vr - 0.08 mg/l in the form of NO2- ion or 0.02 mg/l in terms of nitrogen.

Aluminum- in natural waters aluminum is present in ionic, colloidal and suspended forms. Migration ability is low. It forms fairly stable complexes, including organomineral complexes that are in water in a dissolved or colloidal state.

Aluminum ions are toxic to many types of aquatic organisms and to humans; toxicity is manifested primarily in an acidic environment.

MPC in aluminum is 0.5 mg/l (limiting indicator of harmfulness - sanitary-toxicological), MPC vr - 0.04 mg/l (limiting indicator - toxicological).

BOD full - total biochemical oxygen demand (BODtotal) is the amount of oxygen required for the oxidation of organic impurities before the start of nitrification processes. The amount of oxygen consumed for the oxidation of ammonium nitrogen to nitrites and nitrates is not taken into account when determining BOD.

The total biochemical oxygen demand BOD n for inland fishery water bodies (categories I and II) at a temperature of 20°C should not exceed 3 mg O 2 /l.

Iron total- the main sources of iron compounds in surface waters are the processes of chemical weathering of rocks, accompanied by their mechanical destruction and dissolution. In the process of interaction with mineral and organic substances contained in natural waters, a complex complex of iron compounds is formed, which are in water in dissolved, colloidal and suspended states.

MPC in iron is 0.3 mg/l (limiting indicator of harmfulness - organoleptic). MPC vr - 0.1 mg / l (limiting indicator of harmfulness - toxicological).

Copper- one of the most important trace elements. The physiological activity of copper is associated mainly with its inclusion in the composition of the active centers of redox enzymes.

Copper can form as a result of corrosion of copper pipes and other structures used in water systems.

For copper, MPC (by copper ion) is set at 1 mg/l (limiting hazard indicator - organoleptic), MPCvr - 0.001 mg/l (limiting hazard indicator - toxicological).

Nickel- in surface waters, nickel compounds are in dissolved, suspended and colloidal states, the quantitative ratio between which depends on the composition of water, temperature and pH. Sorbents of nickel compounds can be iron hydroxide, organic substances, highly dispersed calcium carbonate, clays.

MPC in nickel is 0.1 mg/l (limiting hazard indicator - sanitary-toxicological), MPC vr - 0.01 mg/l (limiting hazard indicator - toxicological).

Zinc - in Zinc exists in water in ionic form or in the form of its mineral and organic complexes, sometimes found in insoluble forms.

Many zinc compounds are toxic, primarily sulfate and chloride. In the aquatic environment, the toxicity of zinc is enhanced by copper and nickel ions.

MPCv Zn2+ is 5.0 mg/l (limiting indicator - organoleptic), MPCvr Zn2+ - 0.01 mg/l (limiting indicator of harmfulness - toxicological).

Efficiency of cleaning pollutants at the OSK in Yoshkar-Ola in 2007.

Name of pollutant	Incoming SW	Purified SW	% cleaning
ammonium ion
Aluminum
BOD full
suspended solids
Iron total
Oil products
surfactant (anion act)
sulfates
Sulfides
Phosphates (according to P)
Chromium trivalent
Chromium 6-valent

4 Sources of pollution of a water body depending on the landscape structure of the area

I. Within the boundaries of large cities, the preservation of river valleys in a natural state is impossible without constant environmental protection measures, since the negative anthropogenic impact is especially strong here.

The assessment of the quality of a site of landscape complexes is carried out according to a number of natural parameters, among which one can single out the area of ​​the site, the biodiversity index, anthropogenic transformation, vulnerability to anthropogenic pressures, historical value, position in the ecological space, and potential recreational value. In the conditions of modern cities, the ecological state of the territory, which is characterized by geoecological and biogeochemical conditions, becomes the most important factor.

Ecological conditions are understood as a set of geoecological factors that determine the state of the environment within the territory under consideration. These usually include meteorological and climatic features, atmospheric pollution, the acoustic regime of the territory, its engineering-geological and hydrogeological conditions.

Biogeochemical factors include the following: the degree of disturbance and pollution of the soil cover, the hydrological characteristics of the territory, including the assessment of the hydrological regime of the watercourse, the degree of channel transformation, the level of water pollution in the river, and other hydrochemical indicators of surface runoff within the catchment area.

Joint consideration of all these parameters allows us to give a comprehensive description of the landscape structure of the territory.

1) Assessment of geoecological factors

A) weather conditions. Meteoclimatic changes in background characteristics and redistribution of meteorological elements are determined by the relief of the river valley and its tributaries, the nature of the green cover, and depend on weather conditions. In relief depressions - river floodplains, at night, with anticyclonic weather and radiative cooling, air flow from higher adjacent territories and its stagnation are noted, fogs, surface inversions are formed, contributing to the accumulation of harmful impurities in the surface layer of the atmosphere when they enter.

B) The state of atmospheric air. Pollution of the air basin occurs due to emissions of pollutants from industrial and transport facilities located outside the site, as well as, to a large extent, from the influx of polluted air masses from adjacent territories, creating background pollution. The combination of these factors determines the high level of air pollution in general.

C) Geological environment. The geological structure is characterized by the distribution of the following genetic types of deposits: technogenic bulk soils, modern and ancient alluvial, cover, moraine fluvioglacial, moraine deposits of the Moscow or Dnieper stage of glaciation and fluvioglacial deposits of the Oka-Dnieper interglacial.

2) Assessment of biogeochemical factors

A) ground cover. The foci of technogenic pollution of the soil cover represent an excess concentration of not one, but a whole complex of chemical elements, the cumulative impact of which was estimated by the value of the total concentration index (CIC) - the sum of excesses of accumulating elements over the background level. Depending on the values ​​of this indicator, categories of pollution of territories are distinguished: permissible, moderately dangerous, dangerous and extremely dangerous.

B) Surface water.

C) green space.

Comprehensive assessment of the state of the environment

A) landscape structure of the territory. Currently, natural complexes have undergone significant anthropogenic changes. It is possible to single out a group of complexes where the urban development of the territory has practically not changed in terms of functioning, and sometimes anthropogenic intervention was even beneficial for the natural landscape. In other cases, natural ecosystems have degraded. The tracts of floodplains and partly terraces immediately adjacent to the riverbed have undergone the least transformation, where the native vegetation is replaced by maple plantations with an admixture of elm and willow. Over time, the plantations have lost their aesthetic appeal, and in addition, they have already reached physiological old age, which requires reconstruction measures. In addition, a high degree of dense forest stand contributes to the deterioration of the crime situation.

The natural-territorial complexes occupied by residential and industrial buildings have undergone changes to the greatest extent. The transformation of such complexes has an ambiguous urban planning effect. Vegetation is characterized by the replacement of its indigenous types in residential areas with cultural plantings with an age corresponding to the age of the building. In general, the state of such man-made complexes is satisfactory, except for the territories occupied by industrial facilities, which caused the degradation of green spaces.

B) Analysis of the rehabilitation potential of the river. A comprehensive assessment of the ecological state of the territory is based on landscape and biochemical studies of the resistance of natural complexes to anthropogenic loads, assessment of the state of environmental components, as well as on the analysis of the urban development potential of the site under consideration and the general urban development situation in the urban areas adjacent to it.

The negative natural factors include the presence of steep slopes and flooded areas that are unstable to additional technogenic load. Negative technogenic factors should be considered high littering of the territory in some areas, the impact of polluted and insufficiently treated effluents from residential areas, industrial zones and enterprises that affect the quality of water bodies. Consequently, the state of water bodies does not meet the requirements for cultural and community facilities. In addition, excessive atmospheric air pollution along highways is typical for almost the entire territory.

II. Water bodies, being natural and natural-technogenic elements of landscape-geochemical systems, in most cases are the final link in the runoff accumulation of most of the mobile technogenic substances. In landscape-geochemical systems, substances are transported from higher levels to lower hypsometric levels with surface and underground runoff, and vice versa (from lower to higher levels) - by atmospheric flows and only in some cases by flows of living matter (for example, during a mass departure from water bodies of insects after the completion of the larval stage of development, which takes place in water, etc.).

Landscape elements representing the initial, most highly located links (occupying, for example, local watershed surfaces), are geochemically autonomous and the entry of pollutants into them is limited, except for their entry from the atmosphere. Landscape elements that form the lower stages of the geochemical system (located on slopes and in depressions of the relief) are geochemically subordinate or heteronomous elements that, along with the influx of pollutants from the atmosphere, receive part of the pollutants that come with surface and ground waters from higher-lying landscape links. -geochemical cascade. In this regard, the pollutants formed in the catchment area due to migration in the natural environment sooner or later enter water bodies mainly with surface and groundwater runoff, gradually accumulating in them.

5 The main processes of water self-purification in a water body

Self-purification of water in reservoirs is a set of interrelated hydrodynamic, physicochemical, microbiological and hydrobiological processes leading to the restoration of the original state of a water body.

Among the physical factors, the dilution, dissolution and mixing of incoming contaminants is of paramount importance. Good mixing and reduction of suspended solids concentrations is ensured by the rapid flow of the rivers. It contributes to the self-purification of water bodies by settling to the bottom of insoluble sediments, as well as settling polluted waters. In zones with a temperate climate, the river cleans itself after 200-300 km from the place of pollution, and in the Far North - after 2 thousand km.

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Task number 6

SELF-PURIFICATION PROCESSES OF NATURAL WATERS

1 TYPES OF POLLUTION AND THEIR EFFECTS

(CHANNELS FOR SELF-CLEANING WATER ENVIRONMENT)

Under the self-purification of the aquatic environment understand the totality of physical, biological and chemical inland processes aimed at reducing the content of pollutants (pollutants).

The contribution of individual processes to the ability of the natural aquatic environment to self-purify depends on the nature of pollutants. In accordance with this, pollutants are conditionally divided into three groups.

one). Preservative substances - non-degradable or biodegradable very slowly . These are mineral salts, hydrophobic compounds such as organochlorine pesticides, oil and oil products. The decrease in the concentration of conservative substances in water damage occurs only due to dilution, physical processes of mass transfer, physicochemical processes of complexation, sorption and bioaccumulation. Self-purification has an apparent character, since there is only a redistribution and dispersion of pollutants in the environment, pollution of adjacent objects by it.

2). Biogenic substances - substances involved in the biological cycle. These are mineral forms of nitrogen and phosphorus, easily digestible organic compounds.

In this case, self-purification of the aquatic environment occurs due to biochemical processes.

3). Water-soluble substances that are not involved in the biological cycle, entering water bodies and streams from anthropogenic sources, are often toxic. Self-purification of the aquatic environment from these substances is carried out mainly due to their chemical and microbiological transformation.

The most significant processes for self-purification of the aquatic environment are the following processes:

– physical transfer processes: dilution (mixing), removal of pollutants to neighboring water bodies (downstream), sedimentation of suspended particles, evaporation, sorption (by suspended particles and bottom sediments), bioaccumulation;

– microbiological transformation;

–chemical transformation: sedimentation, hydrolysis, photolysis, redox reactions, etc.

2 DILUTION OF SAT AT WASTEWATER RELEASE

FROM WATER PURIFICATION FACILITIES

The mass of pollutants in wastewater is equal to the mass of pollutants in the mixed flow (wastewater + watercourse water). Material balance equation for pollutants:

Cct q + γ Q Cf = Cv (q + γ Q),

where Cst is the concentration of pollutants in waste water, g/m3 (mg/dm3);

q is the maximum flow rate of wastewater to be discharged into the watercourse, m3/s

γ - mixing ratio

Q is the average monthly flow rate of the watercourse, m3/s;

Cf is the background concentration of pollutants in the watercourse (established according to long-term observations), g/m3 (mg/dm3);

Cv - concentration of pollutants in the watercourse after mixing (dilution), g/m3 (mg/dm3);

From the material balance equation, one can find the concentration of pollutants in the watercourse after dilution:

Cv = https://pandia.ru/text/80/127/images/image002_20.png" width="117" height="73 src=">

L is the distance along the fairway of the watercourse (fairway is the deepest strip of a given body of water) from the point of release to the control point, m;

α is a coefficient depending on the hydraulic conditions of the flow. Coefficient α is calculated according to the equation:

where ξ is a coefficient depending on the location of the wastewater outlet into the watercourse: ξ = 1 for outlet near the shore, ξ = 1.5 when released into the fairway;

φ is the coefficient of tortuosity of the watercourse, i.e. the ratio of the distance between the considered sections of the watercourse along the fairway to the distance along the straight line; D is the turbulent diffusion coefficient .

For lowland rivers and simplified calculations, the turbulent diffusion coefficient is found by the formula:

https://pandia.ru/text/80/127/images/image005_9.png" width="59 height=47" height="47">= X-in,

where ac, aw are the activities of substance A in the sorption layer and in the aqueous phase;

γc, γw are the activity coefficients of substance A in the sorption layer and in the aqueous phase;

Cs, Sv are the concentrations of substance A in the sorption layer and in the aqueous phase;

Кс-в - distribution coefficient of substance A (equilibrium constant

AB ↔ AC expressed in terms of concentrations).

Then, with a relatively constant activity coefficient of substance A in the sorption layer (organic phase):

X-in = Ka s-in DIV_ADBLOCK4">

This, in particular, determines the existence of a correlation between the distribution coefficients of substances in the system octanol - water and solid organic matter - water:

Ks-in ≈ 0.4 Ko-in ,

where Ko-v is the distribution coefficient of the substance in the octanol-water system.

The value of Ko-in is related to the solubility of a substance in water by a simple empirical relationship:

lg Ko-in = (4.5 ÷ 0.75) lg S,

where S is the solubility of the substance, expressed in mg/dm3.

This ratio holds for many classes of organic compounds, including hydrocarbons, halogenated hydrocarbons, aromatic acids, organochlorine pesticides, chlorinated biphenyls.

In natural sorbents, organic matter makes up only a certain fraction of the mass of the sorbent. Therefore, the distribution coefficient in the sorbent-water system Ks-v is normalized to the content of organic carbon in the sorbent Ks-v*:

Ks-in * \u003d Ks-in ω (C),

where ω(С) is the mass fraction of organic matter in the sorbent.

In this case, the proportion of the substance sorbed from the aqueous medium ωsorb is equal to:

ωsorb = https://pandia.ru/text/80/127/images/image009_9.png" width="103" height="59">,

where Csorb is the concentration of the sorbent suspended in water.

In bottom sediments, the Csorb value is significant; therefore, for many pollutants Ks-v*· Csorb >> 1, and the unit in the denominator can be neglected. The value of ωsorb tends to unity, i.e., all substance A will be in the sorbed state.

In open water bodies, the situation is different: the concentration of the suspended sorbent is extremely low. Therefore, sorption processes make a significant contribution to the self-purification of the reservoir only for compounds with Ks-v ≥ 105.

Sorption of many pollutants with a water solubility of 10-3 mol/l is one of the main processes for removing a chemical from the aqueous phase. These substances include organochlorine pesticides, polychlorinated biphenyls, PAHs. These compounds are slightly soluble in water and have high Co-in values ​​(104 - 107). Sorption is the most effective way of self-purification of the aquatic environment from such substances.

4 MICROBIOLOGICAL SELF-CLEANING

Microbiological transformation of pollutants is considered one of the main channels of self-purification of the aquatic environment. . Microbiological biochemical processes include reactions of several types. These are reactions involving redox and hydrolytic enzymes. The optimal temperature for the processes of pollutant biodegradation is 25-30ºС.

The rate of microbiological transformation of a substance depends not only on its properties and structure, but also on the metabolic capacity of the microbial community..png" width="113" height="44 src=">,

where CS is the concentration of the substrate (pollutant), . Here keff is the rate constant of biolysis, .m is the biomass of microorganisms or the population size.

The kinetics of the pseudo-first order transformation of some pollutants at a fixed population size and the directly proportional growth of the rate constant with an increase in the number of bacteria have been experimentally proven in many cases. Moreover, in some cases, kef does not depend on the phase of population growth, on the locality and species composition of the microbial community.

When integrating the kinetic equation of the first order reaction, we obtain:

https://pandia.ru/text/80/127/images/image013_7.png" width="29" height="25 src="> – the initial concentration of the substrate (or biochemically oxidizable substances, corresponding to BODtotal);

– current concentration of the substrate (or biochemically oxidizable substances, corresponding to BODtotal – BODτ).

When replacing https://pandia.ru/text/80/127/images/image014_8.png" width="29" height="25"> with the corresponding BOD value in the equation, we get:

.

Let us denote kB/2.303 = k*, where k* is the biochemical oxidation constant (has the dimension of the first-order reaction constant - day-1). When potentiating the equation, we have an equation relating BODtot. and BODτ, in exponential form:

Using this equation, one can determine the time of complete oxidation of biochemically oxidized substances - the time during which 99% of the substance is oxidized .

Under natural conditions of middle latitudes, as a result of microbiological processes, alkanes of a normal structure decompose most quickly (by 60-90% in three weeks). Branched alkanes and cycloalkanes decompose more slowly than n-alkanes - by 40% in a week, by 80% in three weeks. Low molecular weight benzene derivatives mineralize faster than saturated hydrocarbons (for example, phenols and cresols) . Substituted di - and trichlorophenols decompose completely in bottom sediments within a week, nitrophenols - within two to three weeks. However, PAHs are slowly degraded.

Biodegradation processes are influenced by many factors: lighting, dissolved oxygen content, pH , nutrient content, presence of toxicants, etc. . Even if microorganisms have a set of enzymes necessary for the destruction of pollutants, they may not show activity due to the lack of additional substrates or factors.

5 HYDROLYSIS

Many pollutants are weak acids or bases and are involved in acid-base transformations. Salts formed from weak bases or weak acids undergo hydrolysis . Salts formed by weak bases are hydrolyzed by the cation, salts formed by weak acids by the anion. HM, Fe3+, Al3+ cations undergo hydrolysis:

Fe3+ + HOH ↔ FeOH2+ + H+

Al3+ + HOH ↔ AlOH2+ + H+

Cu2+ + HOH ↔ CuOH+ + H+

Pb2+ + HOH ↔ PbOH+ + H+.

These processes cause acidification of the environment.

Anions of weak acids are hydrolyzed:

CO32- + HOH ↔ HCO3- + OH-

SiO32- + HOH ↔ HSiO3- + OH-

PO43- + HOH ↔ HPO42- + OH-

S2- + HOH ↔ HS- + OH-,

which contributes to the alkalization of the environment.

The simultaneous presence of hydrolyzable cations and anions in some cases causes complete irreversible hydrolysis, which can lead to the formation of precipitates of poorly soluble hydroxides Fe (OH) 3, Al (OH) 3, etc.

Hydrolysis of cations and anions proceeds rapidly, as it refers to ion exchange reactions.

Among organic compounds, esters and amides of carboxylic acids and various phosphorus-containing acids undergo hydrolysis. In this case, water participates in the reaction not only as a solvent, but also as a reagent:

R1–COO–R2 + HOH ↔ R1–COOH + R2OH

R1–COO–NH2 + HOH ↔ R1–COOH + NH3

(R1O)(R2O)–P=O(OR3) + HOH ↔ H3PO4 + R1OH + R2OH + R3OH

As an example, dichlorvos (o,o-diethyl-2,2-dichlorovinyl phosphate) can be mentioned.

(C2H5O)2–P=O(O–CH=CCl2) + 2HOH ↔ (HO)2–P=O(O–CH=CCl2) + 2C2H5OH

Various organohalogen compounds are also hydrolyzed:

R–Cl + HOH ↔ R–OH + HCl;

R–C–Cl2 + 2HOH ↔ R–C–(OH)2 + 2HCl ↔ R–C=O + H2O + 2HCl;

R–C–Cl3 + 3HOH ↔ R–C–(OH)3 + 3HCl ↔ R–COOH + 2H2O + 3HCl.

These hydrolytic processes take place on a different time scale. Hydrolysis reactions can be carried out both without a catalyst and with the participation of acids and bases dissolved in natural waters as catalysts. Accordingly, the hydrolysis rate constant can be represented as:

where https://pandia.ru/text/80/127/images/image020_5.png" width="12" height="19"> – rate constants of acid hydrolysis, hydrolysis in neutral medium and alkaline hydrolysis;

In this case, hydrolysis can be considered a pseudo-first order reaction, since pollutants are present in natural waters in trace amounts. The concentration of water in comparison with their concentrations is much higher and is practically considered unchanged.

To determine the concentration of a pollutant that changes over time, a first-order kinetic reaction equation is used:

where C0 – initial concentration of the pollutant;

WITH – current concentration of the pollutant;

τ – the time elapsed from the start of the reaction;

k – reaction (hydrolysis) rate constant.

The degree of conversion of the pollutant (the proportion of the substance that entered into the reaction) can be calculated by the equation:

β = (С0 – С)/С0 = 1– e-kτ.

6 EXAMPLES OF SOLVING PROBLEMS

Example 1 Calculate the concentration of Fe3+ iron ions in river water at a distance of 500 m from the wastewater outlet, if its concentration in the wastewater at the outlet to the reservoir is 0.75 mg/dm3. The speed of the river flow is 0.18 m/s, the volumetric flow is 62 m3/s, the depth of the river is 1.8 m, the river sinuosity coefficient is 1.0. Wastewater is discharged from the shore. The volume flow of wastewater is 0.005 m3/s. The background concentration of Fe3+ is 0.3 mg/dm3.

Solution:

The turbulent diffusion coefficient is

https://pandia.ru/text/80/127/images/image025_3.png" width="147" height="43">.

The coefficient α according to the condition of the problem (the coefficient taking into account the conditions for the discharge of wastewater ξ = 1 when discharged near the coast; the coefficient of river meandering φ = 1) is calculated by the equation:

= 1.0 1.0https://pandia.ru/text/80/127/images/image028_2.png" width="44" height="28 src="> and find its numerical value

β = https://pandia.ru/text/80/127/images/image030_2.png" width="107" height="73">.png" width="145" height="51 src="> .= 0.302 ≈ 0.3 mg/dm3.

Answer: The concentration of Fe3+ at a distance of 500 m from the place of wastewater discharge is 0.302 mg/dm3, i.e., it is practically equal to the background concentration

Example 2 Calculate the biooxidation rate constant k* if it is experimentally established that BODtotal is observed on the 13th day of sample incubation. What proportion of BODtotal is BOD5 in this case?

Solution:

To determine BODtotal, it is assumed that BODtotal: (BODtotal - BODτ) = 100: 1, i.e. 99% of organic substances are oxidized.

k* = https://pandia.ru/text/80/127/images/image035_1.png" width="72" height="47"> = 1 – 10-k*5 = 1 – 10-0.15 ∙5 = 0.822 or 82.2%.

Answer : Biooxidation rate constant is 0.15 day-1. BOD5 of BODtotal is 82.2%.

Example 3 Calculate the half-life, the degree of hydrolysis and the concentration of methylchoracetate (ClCH2COOCH3) at T = 298K in a stagnant water body with pH = 6.9 after: a) 1 hour; b) 1 day after its entry into the reservoir, if its initial concentration was 0.001 mg/l. The rate constants of hydrolysis of methyl chloroacetate are given in the table.

Solution:

In accordance with the law of mass action, the rate of hydrolysis is

where kHYDR is the hydrolysis rate constant, s-1;

SZV - concentration of pollutants.

Hydrolysis can be considered a pseudo-first order reaction, since pollutants are present in natural waters in trace amounts. The concentration of water in comparison with their concentrations is much higher and is practically considered unchanged.

The hydrolysis constant is calculated by the equation

where https://pandia.ru/text/80/127/images/image020_5.png" width="12" height="19"> – rate constants of acid hydrolysis, hydrolysis in a neutral medium and alkaline hydrolysis (see table in the appendix);

СH+.– concentration of hydrogen ions, mol/l;

СOH is the concentration of hydroxide ions, mol/l.

Since, according to the condition of the problem, pH \u003d 6.9, it is possible to find the concentration of hydrogen ions and the concentration of hydroxide ions.

The concentration of hydrogen ions (mol / l) is equal to:

CH+. \u003d 10 - pH \u003d 10-6.9 \u003d 1.26 10-7.

The sum of the hydrogen and hydroxyl exponents is always constant

Therefore, knowing the pH, you can find the hydroxyl index and the concentration of hydroxide ions.

pOH = 14 - pH = 14 - 6.9 = 7.1

The concentration of hydroxide ions (mol/l) is equal to:

COH - \u003d 10–pOH \u003d 10-7.1 \u003d 7.9 10-8.

The hydrolysis constant of methyl chloroacetate is:

2.1 10-7 1.26 10-7+8.5 10-5+140 7.9 10-8=.

8.5 10-5 + 1.1 10-5 = 9.6 10-5s-1.

The half-life of a substance τ0.5 in a first-order reaction is:

https://pandia.ru/text/80/127/images/image037_1.png" width="155" height="47">s = 2 hours.

The degree of conversion (degree of hydrolysis) of the pollutant can be calculated by the equation:

β = (С0 – С)/С0 = 1– e-kτ.

An hour after the entry of methyl chloroacetate into the reservoir, its degree of hydrolysis is equal to:

β = 1– e-0.000096 3600 = 1– 0.708 = 0.292 (or 29.2%).

After a day, the degree of hydrolysis of pollutants is equal to:

β = 1– e-0.000096 24 3600 = 1– 0.00025 = 0.99975 (or 99.98%).

The current concentration of methyl chloroacetate can be determined by knowing its degree of conversion С = С0(1 – β).

An hour after the entry of methyl chloroacetate into the reservoir, its concentration will be:

C \u003d C0 (1 - β) \u003d 0.001 (1 - 0.292) \u003d 0.001 0.708 \u003d 7.08 10-4 mg / l.

In a day, the concentration of pollutants will be equal to:

C \u003d C0 (1 - β) \u003d 0.001 (1 - 0.99975) \u003d 0.001 0.00025 \u003d 2.5 10-7 mg / l.

Answer: The half-life of methyl chloroacetate is 2 hours. An hour after the pollutant enters the reservoir, its conversion rate will be 29.2%, the concentration will be 7.08 10-4 mg/l. A day after the pollutant enters the reservoir, its conversion rate will be 99.98%, the concentration will be 2.5 10-7 mg/l.

7 TASKS FOR INDEPENDENT SOLUTION

1. Calculate the concentration of Cu2+ ions in river water at a distance of 500m from the wastewater outlet, if the concentration of Cu2+ in wastewater is 0.015 mg/l. The speed of the river flow is 0.25 m/s, the volumetric flow is 70 m3/s, the depth of the river is 3 m, the coefficient of river sinuosity is 1.2. Wastewater is discharged from the shore. The volume flow of wastewater is 0.05 m3/s. The background concentration of Cu2+ is 0.010 mg/l.

2. Calculate the concentration of NH4+ ions in the river water at a distance of 800m from the wastewater outlet, if the concentration of NH4+ in the wastewater is 0.25 mg/l. The speed of the river flow is 0.18 m/s, the volume flow is 50 m3/s, the depth of the river is 1.8 m, the coefficient of river meandering is 1.2. Wastewater is discharged from the shore. The volume flow of wastewater is 0.04 m3/s. The background concentration of NH4+ is 0.045 mg/l.

3. Calculate the concentration of Al3+ ions in river water at a distance of 500m from the wastewater outlet, if the concentration of Al3+ in wastewater is 0.06 mg/l. The speed of the river flow is 0.25 m/s, the volume flow is 70 m3/s, the depth of the river is 3 m, the coefficient of the river sinuosity is 1.0. Wastewater is discharged from the shore. The volume flow of wastewater is 0.05 m3/s. The background concentration of Al3+ is 0.06 mg/l.

4. Calculate the concentration of Fe3+ ions in river water at a distance of 300m from the wastewater outlet, if the concentration of Fe3+ in wastewater is 0.55 mg/l. The speed of the river flow is 0.20 m/s, the volume flow is 65 m3/s, the depth of the river is 2.5 m, the coefficient of the river sinuosity is 1.1. Wastewater is discharged from the shore. The volume flow of wastewater is 0.45 m3/s. The background concentration of Fe3+ is 0.5 mg/L.

5. Calculate the concentration of sulfate ions in the river water at a distance of 500m from the wastewater outlet, if the concentration of SO42- in the wastewater is 105.0 mg/l. The speed of the river flow is 0.25 m/s, the volumetric flow is 70 m3/s, the depth of the river is 3 m, the coefficient of river sinuosity is 1.2. Wastewater is discharged from the shore. The volume flow of wastewater is 0.05 m3/s. The background concentration of SO42- is 29.3 mg/l.

6. Calculate the concentration of chloride ions in river water at a distance of 500m from the wastewater outlet, if the concentration of Cl - in wastewater is 35.0 mg/l. The speed of the river flow is 0.25 m/s, the volume flow is 70 m3/s, the depth of the river is 3 m, the coefficient of the river sinuosity is 1.0. Wastewater is discharged from the shore. The volume flow of wastewater is 0.5 m3/s. The background concentration of SO42- is 22.1 mg/l.

7. The concentration of Cu2+ copper ions in wastewater is 0.02 mg/l. At what distance from the place of wastewater discharge will the concentration of Cu2+ exceed the background by 10% if the volumetric flow rate of wastewater is 0.05 m3/s? The speed of the river flow is 0.15 m/s, the volume flow is 70 m3/s, the depth of the river is 3 m, the coefficient of river meandering is 1.2. Wastewater is discharged from the shore. The background concentration of Cu2+ is 0.010 mg/l.

8. As a result of dry deposition from the atmosphere, aerosol particles with a diameter of 50 μm and a density of 2500 kg/m3 entered a flowing reservoir 1.5 m deep. Water flow rate is 0.8 m/s, water viscosity is 1 10-3 Pa s, water density is 1000 kg/m3. What distance will these particles, carried away by the current, overcome before settling to the bottom?

9. As a result of wet deposition from the atmosphere, aerosol particles with a diameter of 20 μm and a density of 2700 kg/m3 entered a flowing reservoir with a depth of 3.0 m. Water flow rate is 0.2 m/s, water viscosity is 1 10-3 Pa s, water density is 1000 kg/m3. What distance will these particles, carried away by the current, overcome before settling to the bottom?

10. As a result of dry deposition from the atmosphere, aerosol particles with a diameter of 40 μm and a density of 2700 kg/m3 entered a flowing reservoir with a depth of 2.0 m. Water flow velocity is 0.25 m/s, water viscosity is 1 10-3 Pa s, water density is 1000 kg/m3. The length of the reservoir in the direction of the current is 5000 m. Will these particles settle to the bottom of the reservoir or will they be carried out by the current?

11. Calculate the diameter of suspended particles entering the flowing reservoir with wastewater, which will settle to the bottom of the reservoir 200m from the wastewater outlet, if the particle density is 2600 kg/m3. The water flow rate is 0.6 m/s, the viscosity of water is 1 10-3 Pa s, the density of water is 1000 kg/m3. The depth of the reservoir is 1.8m.

12. As a result of the accident, hexane spread over the surface of the reservoir. The saturation vapor pressure of hexane at 20°C, 30°C and 40°C is 15998.6 Pa, 24798.0 Pa and 37063.6 Pa, respectively. Determine the saturation vapor pressure of hexane at 15°C graphically. Calculate the evaporation rate of hexane at 15°C using the formula if the wind speed is 1m/s. The density of air at 0°C is 1.29 kg/m3, the viscosity of air at 15°C is 18∙10−6 Pa∙s, the diameter of the spot formed by hexane on the water surface is 100m.

13. As a result of the accident, toluene spread over the surface of the reservoir. The saturation vapor pressure of toluene at 20°C, 30°C and 40°C is 3399.7 Pa, 5266.2 Pa and 8532.6 Pa, respectively. Determine the saturation vapor pressure of toluene at 25°C graphically. Calculate the evaporation rate of toluene at 25°C using the formula if the wind speed is 2m/s. The density of air at 0°C is 1.29 kg/m3, the viscosity of air at 25°C is 20∙10−6 Pa∙s, the diameter of the spot formed by toluene on the water surface is 200m.

14. As a result of the accident, the surface of the reservoir spread m-xylene. Saturated steam pressure m-xylene at 20°C and 30°C is equal to 813.3 and 1466.5 Pa, respectively. Determine the saturation vapor pressure m-xylene at a temperature of 25°C, using the integral form of the chemical reaction isobar equation. Calculate Evaporation Rate m-xylene at 25°C according to the formula, if the wind speed is 5m/s. The density of air at 0°C is 1.29 kg/m3, the viscosity of air at 25°C is 20∙10−6 Pa∙s, the diameter of the spot formed m-xylene on the water surface is equal to 500m.

15. Benzene is accidentally spilled on the laboratory table. The saturation vapor pressure of benzene at 20°C and 30°C is 9959.2 and 15732.0 Pa, respectively. Determine the saturation vapor pressure of benzene at 25°C using the integral form of the chemical reaction isobar equation. Calculate the evaporation rate of benzene at 25°C using the method for determining emissions of harmful substances into the atmosphere. The diameter of the spot formed by benzene on the surface of the table is 0.5 m. Will the MPC value be exceeded. h.(С6Н6) = 5 mg/m3 15 minutes after the spill of benzene, if the volume of the room is 200 m3?

16. Chlorobenzene is accidentally spilled on the laboratory table. The saturation vapor pressure of chlorobenzene at 20°C and 30°C is 1173.2 and 199.8 Pa, respectively. Determine the saturation vapor pressure of chlorobenzene at 25°C using the integral form of the chemical reaction isobar equation. Calculate the evaporation rate of chlorobenzene at 25°C using the atmospheric emission method. The diameter of the spot formed by chlorobenzene on the surface of the table is 0.3 m. Will the MPC value be exceeded. z.(С6Н5Cl) = 50mg/m3 10 minutes after the spill of chlorobenzene, if the volume of the room is 150m3?

17. As a result of the accident, a mixture of octane, toluene and m- xylene weighing 1000 kg. The composition of the mixture (mass fractions): octane - 0.3; toluene - 0.4; m-xylene - 0.3. Saturated vapor pressure of octane, toluene and m-xylene at 20°C is equal to 1386.6; 3399.7 Pa and 813.3 Pa, respectively. Calculate the evaporation rates of hydrocarbons at 20°C using the method for determining emissions of harmful substances into the atmosphere. Determine the composition of the mixture (mass fraction) after an hour, if the diameter of the spot formed by the mixture of hydrocarbons on the water surface is 10 m. The wind speed is 1m/s.

18. As a result of the accident, a mixture of benzene, toluene and m- xylene weighing 1000 kg. The composition of the mixture (mass fractions): benzene - 0.5; toluene - 0.3; m-xylene - 0.2. Saturated vapor pressure of benzene, toluene and m-xylene at 20°C is equal to 9959.2; 3399.7 Pa and 813.3 Pa, respectively. Calculate the evaporation rates of hydrocarbons at 20°C using the method for determining emissions of harmful substances into the atmosphere. Determine the composition of the mixture (wt. fraction) after an hour, if the diameter of the spot formed by the mixture of hydrocarbons on the surface of the water is 12m. The wind speed is 0.5m/s.

19. Calculate the proportion of 2,3,7,8-Cl4-dibenzodioxin adsorbed by suspended particles containing 3.5% (wt.) organic carbon. The concentration of suspended particles in the bottom layers of the reservoir is 12000 ppm. The distribution coefficient of 2,3,7,8-Cl4-dibenzodioxin in the octanol-water KO-B system is 1.047 107.

20. Calculate the proportion of 1,2,3,4-Cl4-dibenzodioxin adsorbed by particulate matter containing 4% (wt.) organic carbon. The concentration of suspended particles in the bottom layers of the reservoir is 10,000 ppm. The distribution coefficient of 1,2,3,4-Cl4-dibenzodioxin in the octanol-water KO-B system is 5.888 105.

21. Calculate the proportion of phenol adsorbed by suspended particles containing 10% (wt.) organic carbon. The concentration of suspended particles in the bottom layers of the reservoir is 50,000 ppm. The distribution coefficient of phenol in the system octanol-water KO-B is 31.

22. Will PbSO4 precipitate form when sewage containing 0.01 mg/l of Pb2+ ions enters a flowing reservoir with a volume flow of 50m3/s? The volume flow rate of waste water is 0.05 m3/s. The background concentration of SO42- is 30 mg/L. Take the mixing ratio γ equal to 1∙10−4. PR(PbSO4) = 1.6 10−8.

23. Will Fe(OH)3 precipitate form when sewage containing 0.7 mg/l of Fe3+ ions enters a flowing reservoir with a volume flow of 60m3/s? The volume flow rate of waste water is 0.06 m3/s. pH = 7.5. Take the mixing ratio γ equal to 4∙10−4. PR(Fe(OH)3) = 6.3 10−38.

24. Calculate the degree of hydrolysis and the concentration of chloroform (CHCl3) at T=298K in a stagnant reservoir with pH=7.5 after: a) 1 day; b) 1 month; c) 1 year after its entry into the reservoir, if its initial concentration was 0.001 mg/l. The rate constants of hydrolysis of chloroform are given in the table.

25. Calculate the degree of hydrolysis (degree of conversion) and the concentration of dichloromethane (CH2Cl2) at T=298K in a stagnant reservoir with pH=8.0 after: a) 1 day; b) 1 month; c) 1 year after its entry into the reservoir, if its initial concentration was 0.001 mg/l. The rate constants of hydrolysis of dichloromethane are given in the table.

26. Calculate the degree of hydrolysis (degree of conversion) and the concentration of bromomethane (CH3Br) at T=298K in a stagnant reservoir with pH=8.0 after: a) 1 day; b) 1 month; c) six months after its entry into the reservoir, if its initial concentration was 0.005 mg/l. The rate constants of hydrolysis, bromine are given in the table.

27. After what time will the concentration of ethyl acetate in a stagnant reservoir become equal to: a) half of the initial concentration; b) 10% of the initial concentration; c) 1% of the initial concentration? T = 298K. pH = 6.5. The rate constants for the hydrolysis of ethyl acetate are given in the table.

28. After what time will the concentration of phenylacetate in a stagnant reservoir become equal to: a) half of the initial concentration; b) 10% of the initial concentration; c) 1% of the initial concentration? T = 298K. pH = 7.8. The rate constants of hydrolysis of phenylacetate are given in the table.

29. After what time will the concentration of phenyl benzoate in a stagnant reservoir become equal to: a) half of the initial concentration; b) 10% of the initial concentration; c) 1% of the initial concentration? T = 298K. pH = 7.5. The rate constants of hydrolysis of phenyl benzoate are given in the table.

30. Calculate the biooxidation constant k* in natural water and the time for removing half of the pollution, if the values ​​of BOD5 and BODtot are experimentally determined, which are equal to 3.0 and 10.0 mgO2/dm3, respectively.

31. Calculate the biooxidation constant k* in natural water and the time for removing half of the pollution, if the values ​​of BOD5 and BODtot are experimentally determined, which are equal to 1.8 and 8.0 mgO2/dm3, respectively.

32. Calculate the biooxidation rate constant k* in natural water, if it is experimentally established that BODtotal is observed on the 13th day of incubation of a sample of this water. What proportion of BODtotal is BOD5 in this case?

33. Calculate the biooxidation rate constant k* in natural water, if it is experimentally established that BODtotal is observed on the 18th day of incubation of a sample of this water. What proportion of BODtotal is BOD5 in this case?

34. The time for complete oxidation of phenol in a pond with natural aeration was 50 days. Calculate the rate constant of biooxidation k* of phenol in this pond, as well as its concentration after 10 days, if the initial concentration of phenol is 20 µg/L.

35. The time of complete oxidation of toluene in a pond with natural aeration was 80 days. Calculate the biooxidation rate constant k* of toluene in this pond, as well as its concentration after 30 days, if the initial concentration of toluene is 50 µg/l.

36. Calculate COD. acetic acid. Calculate the COD of natural water containing 1∙10−4 mol/l acetic acid. Calculate BODtot. of this water if BODtot: COD = 0.8: 1. Calculate

37. Determine the concentration of phenol in the water of a stagnant reservoir one day after its arrival, if the initial concentration of phenol was 0.010 mg/l. Consider that the transformation of phenol occurs mainly as a result of oxidation by the RO2 radical. The stationary concentration of RO2 is 10-9 mol/l. The reaction rate constant is 104 mol l-1 s-1.

38. Determine the concentration of formaldehyde in the water of a stagnant reservoir 2 days after its arrival, if the initial concentration of formaldehyde was 0.05 mg/l. Consider that the transformation of formaldehyde occurs mainly as a result of oxidation by the RO2 radical. The stationary concentration of RO2 is 10-9 mol/l. The reaction rate constant is 0.1 mol l-1 s-1.

APPENDIX

Table - Rate constants of hydrolysis of some organic substances at T = 298K

Substance	Products hydrolysis	Hydrolysis constants
l mol-1 s-1		l mol-1 s-1
ethyl acetate	CH3COOH + C2H5OH
Methyl chloroacetate	СlCH2COOH + CH3OH
Phenyl acetate	CH3COOH + C6H5OH
Phenyl benzoate	C6H5COOH + C6H5OH
Chloromethane CH3Cl
Bromomethane CH3Br
Dichloromethane CH2Cl2
Trichloromethane CHCl3

The negative natural factors include the presence of steep slopes and flooded areas that are unstable to additional technogenic load. Negative technogenic factors should be considered high littering of the territory in some areas, the impact of polluted and insufficiently treated effluents from residential areas, industrial zones and enterprises that affect the quality of water bodies. Consequently, the state of water bodies does not meet the requirements for cultural and community facilities. In addition, excessive atmospheric air pollution along highways is typical for almost the entire territory.

II. Water bodies, being natural and natural-technogenic elements of landscape-geochemical systems, in most cases are the final link in the runoff accumulation of most of the mobile technogenic substances. In landscape-geochemical systems, substances are transported from higher levels to lower hypsometric levels with surface and underground runoff, and back (from lower to higher levels) - by atmospheric flows and only in some cases by flows of living matter (for example, during a mass departure from reservoirs of insects after the completion of the larval stage of development, passing in the water, etc.).

Landscape elements representing the initial, most highly located links (occupying, for example, local watershed surfaces), are geochemically autonomous and the entry of pollutants into them is limited, except for their entry from the atmosphere. Landscape elements that form the lower stages of the geochemical system (located on slopes and in depressions of the relief) are geochemically subordinate or heteronomous elements that, along with the influx of pollutants from the atmosphere, receive part of the pollutants that come with surface and ground waters from higher-lying landscape links. -geochemical cascade. In this regard, the pollutants formed in the catchment area due to migration in the natural environment sooner or later enter water bodies mainly with surface and groundwater runoff, gradually accumulating in them.

5 Main processes of water self-purification in a water body

Self-purification of water in reservoirs is a set of interrelated hydrodynamic, physicochemical, microbiological and hydrobiological processes leading to the restoration of the original state of a water body.

Among the physical factors, the dilution, dissolution and mixing of incoming contaminants is of paramount importance. Good mixing and reduction of suspended solids concentrations is ensured by the rapid flow of the rivers. It contributes to the self-purification of water bodies by settling to the bottom of insoluble sediments, as well as settling polluted waters. In areas with a temperate climate, the river cleans itself after 200-300 km from the place of pollution, and in the Far North - after 2 thousand km.

Disinfection of water occurs under the influence of ultraviolet radiation from the sun. The effect of disinfection is achieved by the direct destructive effect of ultraviolet rays on protein colloids and enzymes of the protoplasm of microbial cells, as well as spore organisms and viruses.

Of the chemical factors of self-purification of water bodies, oxidation of organic and inorganic substances should be noted. Self-purification of a water body is often assessed in relation to easily oxidized organic matter or in terms of the total content of organic substances.

The sanitary regime of a reservoir is characterized primarily by the amount of oxygen dissolved in it. It should beat at least 4 mg per 1 liter of water at any time of the year for reservoirs for reservoirs of the first and second types. The first type includes water bodies used for drinking water supply of enterprises, the second - used for swimming, sporting events, as well as those located within the boundaries of settlements.

The biological factors of self-purification of the reservoir include algae, molds and yeast fungi. However, phytoplankton does not always have a positive effect on self-purification processes: in some cases, the massive development of blue-green algae in artificial reservoirs can be considered as a process of self-pollution.

Representatives of the animal world can also contribute to the self-purification of water bodies from bacteria and viruses. Thus, the oyster and some other amoeba adsorb intestinal and other viruses. Each mollusk filters more than 30 liters of water per day.

The purity of reservoirs is unthinkable without the protection of their vegetation. Only on the basis of a deep knowledge of the ecology of each reservoir, effective control over the development of various living organisms inhabiting it, can positive results be achieved, transparency and high biological productivity of rivers, lakes and reservoirs can be ensured.

Other factors also adversely affect the processes of self-purification of water bodies. Chemical pollution of water bodies with industrial wastewater, biogenic elements (nitrogen, phosphorus, etc.) inhibits natural oxidative processes and kills microorganisms. The same applies to the discharge of thermal wastewater from thermal power plants.

A multi-stage process, sometimes stretching for a long time - self-cleaning from oil. Under natural conditions, the complex of physical processes of self-purification of water from oil consists of a number of components: evaporation; settling of lumps, especially those overloaded with sediment and dust; adhesion of lumps suspended in the water column; floating lumps forming a film with inclusions of water and air; reducing the concentration of suspended and dissolved oil due to settling, floating and mixing with clean water. The intensity of these processes depends on the properties of a particular type of oil (density, viscosity, coefficient of thermal expansion), the presence of colloids in the water, suspended and entrained plankton particles, etc., air temperature and sunlight.

6 Measures to intensify the processes of self-purification of a water body

Self-purification of water is an indispensable link in the water cycle in nature. Pollution of any type during self-purification of water bodies ultimately turns out to be concentrated in the form of waste products and dead bodies of microorganisms, plants and animals that feed on them, which accumulate in the silt mass at the bottom. Water bodies, in which the natural environment can no longer cope with incoming pollutants, are degrading, and this is mainly due to changes in the composition of the biota and disturbances in food chains, primarily the microbial population of the water body. Self-purification processes in such water bodies are minimal or completely stop.

Such changes can only be halted by purposefully influencing the factors that contribute to reducing the formation of waste volumes and reducing pollution emissions.

The task set can be solved only by implementing a system of organizational measures and engineering and reclamation work aimed at restoring the natural environment of water bodies.

When restoring water bodies, it is advisable to start the implementation of a system of organizational measures and engineering and reclamation work with the arrangement of the watershed, and then carry out the cleaning of the water body, followed by the arrangement of coastal and floodplain territories.

The main objective of the ongoing environmental protection measures and engineering and reclamation work in the catchment area is to reduce the generation of waste and prevent unauthorized discharge of pollutants onto the relief of the catchment area, for which the following measures are carried out: introduction of a waste generation rationing system; organization of environmental control in the system of production and consumption waste management; conducting an inventory of facilities and locations for production and consumption waste; reclamation of disturbed lands and their arrangement; tightening fees for unauthorized discharge of pollutants onto the terrain; introduction of low-waste and waste-free technologies and water recycling systems.

Environmental protection measures and works carried out in coastal and floodplain areas include works on leveling the surface, flattening or terracing slopes; construction of hydrotechnical and recreational structures, strengthening of the banks and the restoration of a stable grass cover and tree and shrub vegetation, which subsequently prevent erosion processes. Landscaping works are carried out to restore the natural complex of the water body and transfer most of the surface runoff to the underground horizon in order to clean it up, using the rocks of the coastal zone and floodplain lands as a hydrochemical barrier.

The shores of many water bodies are littered, and the waters are polluted with chemicals, heavy metals, oil products, floating debris, and some of them are eutrophicated and silted. It is impossible to stabilize or activate self-purification processes in such water bodies without special engineering and reclamation intervention.

The purpose of performing engineering and reclamation measures and environmental protection work is to create conditions in water bodies that ensure the effective functioning of various water purification facilities, and to perform work to eliminate or reduce the negative impact of sources of distribution of pollutants, both off-channel and channel origin.