Methods for preserving the lithosphere from pollution. Lithosphere protection methods

Soil protection from progressive degradation and unreasonable losses is the most acute environmental problem in agriculture, which is still far from being solved. The basic links in the ecological protection of soils include:

Soil protection from water and wind erosion;

Organization of crop rotation and tillage systems;

Land reclamation measures (combating waterlogging, soil salinization, etc.);

Reclamation of disturbed soil cover;

Protection of soils from pollution, and beneficial flora and fauna from destruction;

Prevention of unjustified withdrawal of land from agricultural circulation.

To combat soil erosion, a set of measures is needed: land management, agrotechnical, forest reclamation and hydraulic engineering. At the same time, it is taken into account that hydrotechnical measures stop the development of erosion in a certain area immediately after their installation, agrotechnical measures - after a few years, and forest reclamation - 10-20 years after their implementation.

To prevent secondary salinization of soils, it is necessary to arrange drainage, regulate water supply, apply sprinkling irrigation, use drip and root irrigation, perform waterproofing of irrigation canals, etc.

To prevent soil contamination with pesticides and other harmful substances, ecological methods of plant protection (biological, agrotechnical, etc.) are used, the natural ability of soils to self-cleanse is increased, and especially dangerous and persistent insecticidal preparations are not used, etc.

When carrying out construction and other works related to mechanical disturbance of the soil cover, it is envisaged to remove, preserve and apply the fertile soil layer on the disturbed lands. The fertile layer is taken out and stored in special temporary dumps (piles). Reclamation (restoration) of disturbed lands is carried out sequentially, in stages. In addition to technical reclamation, there are also biological and building reclamation.

Subsoil is subject to protection from depletion of mineral resources and pollution. It is also necessary to prevent the harmful impact of the subsoil on the environment during their development. According to the current legislation, in order to prevent environmental damage to subsoil, in particular, it is necessary:

To fully extract from the subsoil and rationally use the reserves of basic minerals and associated components;

To prevent the harmful effect of mining operations on the safety of mineral reserves;

Protect deposits from flooding, flooding, fires, etc.;

Prevent pollution of subsoil during underground storage of oil, gas and other substances, disposal of hazardous substances and production waste.

To prevent possible exhaustion natural resources and conservation of subsoil reserves, it is especially important to observe the principle of the most complete extraction of basic and associated minerals from the subsoil. This will reduce the scale of unjustified penetration into the earth's interior, which will significantly reduce waste from mining enterprises and improve the environmental situation.

One of the important problems associated with the protection and rational use of mineral resources is the integrated use of mineral raw materials, including the problem of waste disposal. The main directions of waste disposal and improvement of the environmental situation are their use as raw materials, in industry and construction, for backfilling goaf and for the production of fertilizers. Liquid waste after treatment is mainly used for water supply and irrigation, gaseous - for heating and gas supply.

The strategic line of protection and rational use of rock massifs (landslide, mudflow, karst, etc.) should be presented as follows:

Violation of the natural balance and changes in the environment during construction work are inevitable, however, violations that are harmful and dangerous in terms of their environmental consequences should not be allowed;

Gradually move from environmental protection of individual sites and areas to comprehensive environmental protection the entire natural massif;

In areas with difficult natural conditions it is very important to take into account the interconnection and interdependence of anthropogenic and natural geological processes. The surveyor and designer must anticipate adverse environmental chain reactions;

Preference should be given to preventive methods of control, it is more profitable and effective;

Do not apply such control measures that give rise to new negative phenomena;

Do not violate natural monuments (unique geological sections, geomorphological elements, karst caves, etc.).

So, for example, effective protection of landslide areas from anthropogenic impact consists in maintaining a stable state of the slopes during the entire life of the structure. For this purpose, surface runoff is regulated, slope leveling is carried out, bare slopes are trimmed, forest reclamation work is carried out, etc. On landslide slopes, the construction of various structures, the discharge of industrial and utility water, the cutting of trees, excessive grazing of livestock, slope trimming, dredging, etc. are prohibited. When it is extremely important, active engineering measures are carried out: 1) redistribute the masses of rocks on the slope; 2) arrange retaining and anchor structures; 3) artificially improve soil properties; 4) drain groundwater, etc.

Protection of the lithosphere - concept and types. Classification and features of the category "Protection of the lithosphere" 2017, 2018.

Protection of the lithosphere provides for a set of measures:

preservation of landscapes during construction, mining, melioration;

conservation of the soil fund (protection from physical disturbance and chemical pollution);

reducing the impact on the lithosphere of production and consumption waste.

It is possible to save the soil fund only if it is properly exploited. During construction, the fertile layer of soil must be removed and rationally used. The costs of removal and storage are included in the cost of production in the development of mineral deposits, or in the cost of facilities under construction. The reclamation of quarries should be carried out in a timely manner, since the exposed soil surfaces are subject to intense erosion. Used lands must be brought to their original form through technical and biological reclamation.

Particular attention should be paid to the high culture of agriculture, the restoration of destroyed soils, the widespread introduction of biotechnologies (some examples of the use of biotechnologies were given in lecture 8 of part I of this manual). Erosion and desertification control should include:

correct crop rotation;

consolidation and development of sands. For this, mechanical protection techniques are used, such as: installation of shields and fences, bituminization of sand. Sprinkling of the bitumen emulsion firmly cements the surface layer of the earth by 0.8–1.0 cm. Such a crust resists winds for about 2 years;

introduction of soil-protective field and grassland crop rotations;

hydraulic structures;

planting forest plantations. nature uses different ways to expand the area of ​​​​forests: nuts that float from one island to another, seeds carried by the wind, fragrant fruits that attract animals. The creation of windbreaks will make it possible to increase the yield of fields by 5 times compared to unprotected ones.

Protecting soils from chemicals primarily involves the use of a limited amount of fast-degrading pesticides or their replacement with natural (environmentally friendly) methods of insect control.

It remains to add that the reduction of soil pollution with pollutants due to atmospheric precipitation and filtration of polluted wastewater will be possible due to the introduction of effective methods for treating gaseous emissions and wastewater.

Reducing the impact of production waste on the lithosphere should first of all include the construction of waste-free production and the recycling of raw materials. Waste - these are types of raw materials not suitable for the production of this type of product, its unusable residues or those arising during technological processes substances (solid, liquid and gaseous) and energy that are not subject to utilization in the production under consideration. Wasteless technology can be considered as a technology that gives the technically achieved minimum amount of waste, i.e. low-waste. Achieving complete zero-waste is practically unrealistic, so the waste from one production should be used as a raw material for another.

Those wastes that cannot be used at present are subject to burial in landfills and landfills or incineration. The storage of solid industrial waste on the seabed is widespread, often near the coast and in shallow water. Deep-water discharges of solid waste are spreading. According to the 1972 Convention on the Prevention of Pollution of the Seas by Discharges from Ships and Aircraft, concluded in Oslo, dumping of containers with solid waste must be carried out above depths of at least 2 thousand meters, at a distance of at least 150 nautical miles from the coast and 20 miles from the nearest submarine cable . Burial as a method, still widely used in our country, can only be considered as a temporary measure of waste disposal, since most of them decompose extremely slowly and thousands of tons of valuable secondary raw materials are withdrawn from circulation.

The issue of disposal of solid household waste(MSW) is a special issue. Changes in our way of life, increased consumption with a rapid increase in production, the release of disposable products or products that are not designed to last, lead to an increase in the total mass of household waste. It is unacceptable to collect garbage in landfills, because they require more and more space, waste can supply toxic substances to soils and groundwater. Waste must be disposed of. In table. 11 shows the approximate composition of MSW.

Table 11

Approximate composition of municipal solid waste

Glass bottles can be reused up to 30 times, aluminum and steel can be recycled. Recycling technologies save energy, reduce emissions of harmful substances into the atmosphere and save water. In table. 12 evaluated the environmental benefits of recycling.

Table 12

Save energy and reduce pollution environment

during recycling, %

Environmental benefits	Aluminum
Decrease in consumption
Pollution reduction atmosphere
Reducing water pollution
Reduced water consumption

For high-quality disposal of municipal solid waste, they must be sorted. No other more environmentally sound method of dealing with MSW has yet been found. Sorting can be done by centralized points, but it is better if consumers do it themselves. Therefore, the solution of the MSW problem will depend, first of all, on the environmental education of the population.

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The main directions in the development of solid waste management methods are:

• - development of technologies aimed at reducing (minimizing) waste generation;
• - use of waste as secondary material resources;
• - placement or deposition (storage) of waste;
• - recycling.

Waste minimization based on the principles of creating low-waste or clean production. It includes the development of new environmental technologies, the improvement of apparatus designs or technological methods, the integrated use of raw materials, the use of waste as secondary resources. The development of new environmental technologies is based on the fact that when they are implemented, the formation of toxic waste is sharply reduced or completely eliminated. Improving the design of apparatuses and technological methods also contributes to the reduction of waste generation. Methods for the integrated use of raw materials when using new technologies make it possible to obtain additional or new commercial products.

Use of waste as secondary raw materials is based on the organization of the cyclical nature of material flows, which makes it possible to involve production waste in technogenic circulation to obtain products in other industries.

Waste disposal It is a procedure for the storage and disposal of waste. Waste storage involves the maintenance of waste at special facilities for the purpose of their subsequent burial, neutralization or use. Waste disposal is the isolation of waste that cannot be used in special storage facilities in order to prevent the penetration of harmful substances into the environment.

Waste disposal involves waste treatment, including waste disposal at specialized facilities. The most widely used thermal methods of solid waste processing.

The protection of the lithosphere includes not only the deposition of liquid and solid wastes by placing them in landfills, but also their processing and disposal using various methods(Fig. 2.13).

Currently, the problem of sludge in the form of sediments and excess activated sludge of sewage, the volume of which is about 1% of the volume of wastewater, is becoming more and more apparent. Modern technological processes for the treatment of sewage sludge include general view the following stages: main - compaction, dehydration, thermal drying or disinfection, elimination or disposal; auxiliary - stabilization and conditioning (Fig. 2.14).

Rice. 2.14.

Raw sludge and activated sludge treatment includes the following processes:

• - sludge compaction by gravity, flotation, centrifugal and vibration methods;
• - stabilization of precipitation under aerobic and anaerobic conditions;
• - conditioning of precipitation by reagent and non-reagent methods;
• - heat treatment;
• - liquid-phase oxidation of the organic part of the sediment with atmospheric oxygen;
• - dehydration of sediments on sludge sites in a natural way and mechanically;
• - drying of sediments;
• - burning of precipitation.

The main component of raw sludge, excess and compacted activated sludge, as well as digested sludge is water (up to 95%), which is poorly separated from mineral and organic particles. To increase water yield, it is necessary to change the structure of the solid phase of the sediment. This is achieved in several ways: their coagulation with chemical reagents, flocculation, the introduction of filler materials, thermal conditioning, magnetic and electromagnetic processing.

In the practice of treating sewage sludge, chemical (reagent) treatment methods are most often used. Relatively widespread in the field of urban sewage sludge treatment is its thermal drying.

The sludge emitted during the treatment of wastewater from cities and populated areas with a small proportion of untreated industrial effluents, according to chemical composition refers to valuable organo-mineral mixtures, which allows it to be used as a fertilizer, as well as energy resources and raw materials for many types of products.

Modern directions in the field of application of solid industrial waste are:

• - use of waste for landscape reclamation, territory planning, road filling;
• - the use of waste as a raw material in the production of building materials;
• - use of waste in agriculture as fertilizers or means of melioration;
• - integrated use of raw materials and waste as a secondary raw material resource for the production of new types of products.

For solid industrial waste that cannot be used directly, mechanical grinding or compaction (pressing) is used.

For size separation of processed lumpy and bulk materials, sieving (screening) methods, separation under the action of gravitational, inertial and centrifugal forces are used.

In the recovery technology of bulk solid waste, methods of granulation, tableting and briquetting are used.

When enriching solid waste, gravity, magnetic, electric and flotation methods are used.

When disposing of solid waste, physical and chemical methods of leaching (extraction), dissolution, crystallization and drying of processed materials are used.

If the waste cannot be used in industry, then it must be disposed of. There are three ways to store industrial waste: in sludge storages, at landfills, injection into deep horizons.

Sludge storage- these are specially built surface open structures designed for storage and settling of low-toxic sludge - waste of IV and V hazard groups. They are equipped with a special drainage system to remove water, and their bottom and banks are insulated with a waterproof layer.

Polygons are environmental structures designed for centralized collection, removal, isolation, neutralization and storage of non-recyclable waste. The processing of industrial waste at the landfill is carried out in such a way that it is either completely destroyed or converted into water-insoluble residues that can be stored at landfills in maps-platforms, with minimal risk of groundwater pollution. Toxic industrial waste is taken to special landfills for neutralization using a special technology and burial in containers or on special maps-sites. Only toxic industrial wastes of I, II, III and, if necessary, IV hazard classes are subject to admission to a special landfill. The following types of waste are not subject to admission to the landfill for the disposal of toxic industrial waste:

• a) waste for which they are designed effective methods extraction of metals or other substances;
• b) radioactive waste;
• c) oil products subject to regeneration.

The processing of toxic waste entering the landfill is carried out at a plant for the neutralization of hazardous industrial waste. The plant is designed for incineration and physico-chemical processing of waste in order to neutralize or reduce toxicity (hazard class), convert them into insoluble forms, dehydrate and reduce the amount of waste to be disposed of. The most common solid waste disposal methods are:

• - for not organic matter- physico-chemical treatment in several stages, which leads to the formation of harmless, in most cases neutral, water-insoluble compounds;
• - for waste of organic origin - incineration at high temperatures.

The size of the landfill site for toxic industrial waste is established

based on the period of accumulation of waste within 20 ... 25 years. The dimensions of the sanitary protection zone (SPZ) of the toxic industrial waste disposal site to settlements and open water bodies, as well as to objects used for cultural and recreational purposes, are set at least 3000 m.

For municipal solid waste (MSW), the following methods of disposal and disposal are most widely used:

• - warehousing (liquidation biological);
• - burning (liquidation thermal);
• - composting (biological utilization).

Ecological analysis showed that they have approximately equal indicators in terms of their impact on the environment.

Municipal solid waste is collected, transported and deposited (stored) at landfills for solid waste. The most common facilities for the neutralization of municipal solid waste removed from the city are landfills. Waste from residential buildings, public buildings and institutions, trade enterprises, public catering, street and garden estimates, construction garbage and some types of solid industrial waste of hazard classes 3 and 4, as well as non-hazardous waste of class 5. The main structure of the landfill is the solid waste storage area. The area of ​​the site allotted for the solid waste landfill is selected from the condition of its operation life of at least 15 ... 20 years. The size of the sanitary protection zone from residential development to the boundaries of the solid waste landfill is 500 m.

Injection of waste into deep horizons carried out through absorbing wells below the groundwater level to a depth of several hundred meters to 4000 m. The method requires constant monitoring of the condition of the wells.

Utilization of radioactive waste. Low-level waste does not require special isolation. Usually they are pre-pressed or burned and transferred to surface disposal. Moderately toxic radioactive industrial waste after treatment is subject to isolation and disposal. High-level waste is subject to special treatment and disposal in deep geological formations.

Lecture No. 6,7

POLLUTION OF THE LITHOSPHERE AND ITS PROTECTION. DISPOSAL AND PROCESSING OF WASTE

Plan

1. Pollution of the lithosphere and its protection: inclusion of pollution in the power circuit; main sources of soil pollution. MPKprod, VDK and DOK. Basic methods of soil protection from pollution.

Road operation in winter time, associated with the use of special chemicals to clean the road from ice, also negatively affects the condition of the territory adjacent to the road and the places where these chemicals are stored. In cities, every year it is necessary to restore green spaces along the roads that have died as a result of soil salinization.

Pollution of the roadside with oil products, heavy metals, chlorides and other pollutants is exacerbated by soil compaction. As a result, the moisture capacity and aeration of the soil are reduced. Recovery processes occur in compacted soil, especially if the remaining oxygen is displaced by moisture or other soil gases. The reduction of metal ions leads to the formation of mobile toxic compounds that are easily absorbed by plants. On the other hand, the mobility of these compounds leads to their intense leaching, which reduces the supply of nutrients in the soil.

Highways dismember the existing landscape, thereby violating not only its cultural and aesthetic value, but also the established process of animal migration. This leads to the fact that the existing range of some species of animals is sharply reduced, the previously single population is divided into several isolated parts. The number of these fragmented populations may turn out to be below the critical one, and then they are doomed to extinction. Moreover, crossing migration routes is dangerous not only for animals, because their sudden exit onto the road can lead to serious accidents with human casualties.

When laying roads in dry areas, traffic on them leads to strong dust formation. Broad-leaved crops growing in these areas, such as cotton, are susceptible to pests (spider mites) that breed on plants in conditions of heavy dust. To reduce this effect, special road surfaces are used that exclude dust formation.

Pollution of the lithosphere

While air and water pollution can be noticed or detected, soil pollution can remain hidden for a long time. As a rule, people do not come into such close contact with the soil as they do with air or water. The soil is opaque, in most cases it has a significant buffering effect, which allows pollution to remain unnoticed for a long time. But when the adsorption capacity is exhausted, slip – outwardly unexpected pollution of groundwater, even without the introduction of new quantities of pollutants.

It should also be noted that soils have the ability to regenerate. Many soil inhabitants serve as a source of enzymes, in the presence of which harmful substances are broken down faster than in water or air.

For rate degree of soil pollution use the maximum permissible concentrations of chemicals in the soil (MPC). MPCp is the concentration* of a chemical in topsoil soil, which should not cause direct or indirect negative effects on the environment in contact with the soil and human health, as well as on the self-cleaning capacity of the soil.

There are 4 MPC values ​​depending on the route of chemical substance migration from the soil to adjacent environments:

TV - translocation indicator characterizing the transition of a chemical substance from the soil through root system in green mass and fruits of plants;

MA - migratory air index;

MV - migratory water index;

OS - general sanitary an indicator characterizing the effect of a chemical on the self-cleaning ability of the soil and microbiocenosis.

Anthropogenic pollution of the lithosphere

The main sources of pollution are:

· dumps and storages of toxic waste;

· leaking underground storages and pipelines;

· pesticides and fertilizers;

· anti-icing chemicals used in the road sector;

· fuel oil and waste oil used as a means of binding dust on roadsides;

domestic and industrial waste water;

vehicle accidents;

· deposition of toxic substances (eg acid rain and heavy metal compounds) from the polluted atmosphere.

Pollution from household and industrial waste

The general term for all the many materials that we throw away from homes and institutions and commonly referred to as garbage is - municipal solid waste (MSW). In general, the presence of waste indicates that our society violates one of the main environmental laws - the cycle of substances in nature. The situation with waste is currently characterized as a crisis: there is more and more waste, and there are less and less places for their disposal.

The most serious problem associated with landfills is the contamination of adjacent soils and groundwater. When rainwater passes through untreated waste, a particularly toxic filtrate , which, along with the remains of decaying organic matter, contains iron, mercury, lead, zinc and other metals from rusting cans, discharged batteries and other electrical appliances, and all this is heavily seasoned with dyes, pesticides, detergents and other chemicals.

The second problem is the formation of methane. Buried garbage has no access to oxygen. Therefore, its decomposition is anaerobic, and one of the products of this process is biogas, 2/3 consisting of methane. Formed in the thickness of buried waste, it can spread horizontally, penetrate into the basements of buildings, accumulate there and explode when ignited. In addition, methane can spread upwards, poisoning roots and destroying vegetation at the burial site. In a number of cities, this problem is being solved by constructing “gas wells” on the site of landfills that intercept methane, which can later be used as fuel.

Along with landfills, industrial waste disposal poses a serious environmental hazard. Of these, despite the precautions taken, leakage of pollutants with particular toxicity is possible. In Russia, as noted by some researchers, this problem is complicated by the lack of proper control over the movement and disposal of industrial waste.

Pesticide pollution

Human well-being largely depends on pest control. Were it not for her, we would be living in extremely precarious conditions—our health and food supplies would be at the mercy of other organisms. Today, there are many ways to combat pests, but two diametrically opposed opinions prevail in relation to it.

One of them is based on a purely technological approach. It consists in the search for a “miracle weapon”, most often in the form of a chemical invented by man, which is harmful to the organism of a pest.

The second opinion, which is now called ecological pest control, takes into account the need to maintain the overall ecological balance. It places emphasis on protection human, cultivated plants and animals from damage caused by pests, and not on destruction the latter.

Traditionally, people have chosen a purely technological approach. Thousands of chemicals have been invented to kill pests. They are called pesticides (from lat. Pestis - infection and caedo - I kill). Pesticides are classified according to the groups of organisms they affect. Yes, there are insecticides (kill insects) rodenticides (kill rodents) fungicides (destroy fungi), etc. However, none of these chemicals has absolute selectivity for the organisms against which it is designed, and also poses a threat to other organisms, including humans. Therefore, all this is biocides , i.e. substances that threaten various forms alive.

At first, substances containing heavy metals such as lead, arsenic and mercury were used to control pests. These inorganic compounds are often referred to as first generation pesticides. Such compounds can accumulate in the soil and inhibit plant growth. Many soils were so polluted with heavy metals that after 50 years nothing grows on them. In addition, pests quickly developed resistance to these substances, and therefore the effectiveness of their use decreased.

Therefore, new means of pest control were required. They were second-generation pesticides based on synthetic organic compounds.

The problems associated with synthetic organic compounds can be divided into four categories:

development of resistance in pests;

· revival of pests and secondary outbreaks;

rising costs;

undesirable impact on the environment and human health.

The development of resistance in pests is associated with the variability of pest populations; they represent a dynamic gene pool capable of rapidly evolving. Pesticide treatments create selection pressure leading to population resistance.

Over the years, pesticide use has steadily increased the number of species resistant to them. About 25 major pest species have become resistant to all pesticides. At the same time, cases were noted when the resistance of pest populations to chemicals increased at once.

The increase in costs is associated with the need to use all more ever more expensive pesticides, but with less and less effect.

The problem of the undesirable effects of pesticide use is of the greatest concern to the public. Transmitted and accumulated in food webs, pesticides spread all over the globe. Numerous negative manifestations of the impact of these substances on living organisms, including humans, have been noted. Despite strict controls on the use of pesticides, the problem will continue as long as there are agricultural practices based on their application.

Heavy metal pollution

Pollution with heavy metals significantly affects the soil ecosystem. Lead has a clear tendency to accumulate in the soil, since its ions are inactive even at low pH values. For various soils, the rate of lead leaching ranged from 4 g to 30 g per hectare per year.

The soil becomes dead when it contains 2...3 g of lead per 1 kg of soil. Around some industrial enterprises, the content of lead in the soil reaches a concentration of 10...15 g/kg. According to some reports, the content of lead on the soil surface at the edge of the right of way of highways is usually up to 1 g / kg, but in the dust of city streets it can be 5 times higher [[i]].

Plants are more resistant to lead than animals and humans, so the lead content of plant-based foods must be carefully monitored.

Unlike lead, cadmium ions are highly mobile, especially in acidic soils, so accumulation of this metal is not observed in most cases. Cadmium is introduced into the soil from the air, either together with combustion products, or with phosphorus-containing fertilizers as an impurity.

The mobility of copper ions is even higher than that of cadmium ions. This creates more favorable conditions for the assimilation of copper by plants, as well as the leaching of this substance from the humus layer. Although copper in trace concentrations is considered essential for life, toxic effects in plants appear at a content of 20 mg per kg of dry matter. Copper has a toxic effect on microorganisms, while a concentration of about 0.1 mg / l is sufficient.

Zinc is also a relatively mobile element in the soil. Zinc is one of the most common metals in technology and everyday life, so its annual application to the soil is very large. The soil near zinc processing plants is especially contaminated.

The solubility of zinc in soil begins to increase at pH values ​​less than 6, so zinc does not accumulate in acidic soils. At pH values ​​greater than 6, zinc accumulates in the soil due to interaction with clays. For plants, a toxic effect is created at a content of about 200 mg of zinc per kg of dry matter. The human body is sufficiently resistant to zinc and the risk of poisoning when using agricultural products containing zinc is low.

Protection of the lithosphere

Chemical and biochemical changes in soils and their significance for plants, soil inhabitants, and also for humans should not be considered in isolation or over historically short periods of time. The soil takes part in the formation of local climatic conditions. The elimination of the soil cover leads to the disappearance of vegetation, which leads to the formation of dry deserts, as happened in northern Africa (Sahara desert). Mankind needs to realize the importance of preserving the soil as the basis of its existence and move on to new methods of management that ensure sustainable existence and development.

Soil erosion prevention.

Consider separately the traditional and new methods of soil protection from erosion.

traditional methods.

· Contour plowing (furrows directed perpendicular to the slope).

· Narrow-band sowing (alternating strips of plowed and uncultivated land).

· Protective forest plantations.

Terracing (decoration of slopes in the form of steps).

New methods.

Tillless farming . The purpose of plowing and cultivating the soil is to control weeds. The alternative is chemical herbicides(poisons for weeds), first created in the early 60s. This method has both positive and negative sides. The benefits include saving time and energy - instead of three passes of the technique, one is enough. In addition, since the herbicides are sprayed from the air, there is the possibility of early sowing, and, therefore, a second harvest in one season. These are purely economic reasons for using this method. But it also has environmental benefits: without ploughing, soil structure is preserved, detritus is supplied and, most importantly, erosion is prevented, since the surface of the earth is almost always covered with vegetation.

However, there are strong arguments against this method. First, the use of herbicides may not be safe for humans. Secondly, it is necessary to periodically increase the doses of chemicals or develop new substances, since weeds gradually develop resistance to the herbicides used. Thirdly, the absence of plowing favors the reproduction of agricultural pests living in the soil, which, in turn, causes the need to treat the field with pesticides. In general, the amount of all kinds of chemicals used in no-till farming is 2-6 times more than in traditional farming.

Another possibility to prevent soil erosion is the gradual transition of agriculture from annual crops on perennial. In this case, the need for annual plowing would disappear altogether. The main difficulty here lies in finding and cultivating suitable plant species.

Proper organization of agriculture and forestry plays a huge role in protecting soil from erosion. Here the main points are grazing restriction, reforestation and soil recultivation. When applying irrigation, it is necessary to choose water saving irrigation schemes and provide for mandatory drainage, necessary for "washing" the soil from excess salts (in this case, however, there is a problem of further use of washing water).

Waste control.

The best way to deal with waste is not to produce it at all. Therefore, any state that cares about its future should develop a strategy aimed at stimulating the reduction of the volume of waste produced, waste recycling, the creation of waste-free technologies, and the use of biodegradable chemicals.

Waste reduction

Over the years, the amount of MSW has steadily increased: partly due to population growth, but mainly due to changing lifestyles of people using more and more wrapping and packaging materials, disposable goods. It is possible to significantly reduce the amount of waste by increasing the service life of goods. B. Nebel's book describes an example of using disposable and reusable bottles. It shows that the promotion of reusable bottles, adopted in some US states, not only reduces the amount of waste, but also leads to the growth of local industry and employment.

You can also reduce the amount of waste by lowering the material intensity of goods, reducing their size, and increasing their service life.

Recycling

Industrial waste is divided into solid (metals, wood, plastics, etc.) and liquid (sewage sludge, oil products).

The choice of waste treatment method depends on the type and quality of the waste. Homogeneous waste is easier to recycle. For example, scrap metal and waste after sorting and baling on presses are sent for remelting; waste wood is used for the manufacture of chipboard and fiberboard; slag - for the manufacture of building materials; oil products are recycled, etc. Some types of waste containing toxic substances or valuable materials are subjected to special treatment at landfills.

At present, it is of great benefit waste exchanges, where enterprises can repurchase production waste from each other to use them as raw materials.

Inhomogeneous waste is in most cases not economically feasible to recycle and such waste is considered garbage, the main method of use of which is incineration. A large amount of waste is currently not recycled due to the unprofitability or lack of recycling technologies. They are either buried or stored. Finally, many disposable firms are interested in the current situation, as it allows them to earn income indefinitely.

However, there are many ways recycling various types waste. Many firms are investing in recycling because recycling is cheaper, reduces energy costs (for example, remelting aluminum cans can reduce energy consumption by 90% compared to making aluminum from bauxite), reduces the need for refining equipment, and increases equipment life. All this suggests that the possibilities of making a profit from municipal solid waste are inexhaustible.

2. Waste disposal and recycling

solid waste industrial enterprises are very diverse both in their properties and in their impact on the environment. They usually consist of active substances, which, accumulating in the soil, groundwater and atmosphere, gradually pollute them and cause undesirable effects.

Waste- these are not used directly in the places of their formation, production, household, transport, etc. waste, which can actually or potentially be used as products in other industries National economy or during regeneration. Hazardous waste must be neutralized, and unused waste is considered garbage. Waste can be (Fig. 8.4):

Fig.8.4. Main types of waste

1. Household (communal) solid (including the solid component of wastewater - their sludge) waste that is not disposed of in everyday life, resulting from the depreciation of household items and the very life of people (including baths, laundries, canteens, hospitals, etc.). The problem of household waste is currently very acute in many countries of the world. Thus, about 150 million tons of waste are generated annually in US cities, and by the year 2000 their volume is expected to increase by another 20%. In Japan, the amount of household waste exceeds 72 million tons annually. In the former USSR, in 1985, 217 million m3 of household waste was removed from cities by special vehicles, and in 1988, already 228 million m3. Therefore, for the destruction of household waste abroad began to build powerful incinerators (up to 900 tons or more waste per day) to generate energy. The share of incinerated waste is: for the USA - 3%, Japan - 26%, Germany - 34%, Sweden - 51%, Switzerland - 75%, etc., and only a few of the plants produce electricity. Most incinerators generate steam, which is fed through steam pipelines to neighboring industrial plants or residential areas. In our country, in 1988, 1416 thousand tons of household waste were taken to waste processing plants (that is, ~ 0.5%).

2. Production waste (industrial)- the remains of raw materials, materials, semi-finished products formed during the production of products or the performance of work and have lost their original consumer properties in whole or in part. They can be irretrievable (technological losses: volatilization, waste, shrinkage) and returnable. So far, production waste in Russia is significant: in mechanical engineering and metalworking, the share of metal waste in the total consumption of ferrous metals amounted to 21%, and the share of chips in the formation of metal waste reached 42%. Every year, a significant amount of waste is also generated in the EEC countries: processing industry - 400 million tons, industrial enterprises - 160 million tons, etc. Of the total amount of waste (~ 2.2 billion tons), half is agricultural waste. However, if in the EEC countries 60% of household waste is disposed of, 33% is incinerated and 7% is composted, then over 60% of industrial waste and 95% of agricultural waste are subjected to intensive processing (according to foreign sources).

3. Industrial consumption waste- machines, tools, etc., unsuitable for further use for their intended purpose and decommissioned in the prescribed manner. They can be agricultural, construction, industrial, radioactive, the latter are very dangerous and need to be carefully buried or decontaminated.

IN last years the number of dangerous (toxic) waste - capable of causing poisoning or other damage to living beings. These are, first of all, unused various pesticides in agriculture, industrial waste containing carcinogenic and mutagenic substances, etc. In the USA, 41%) of municipal solid waste (MSW) is classified as "especially hazardous", in Hungary - 33.5%, while in France - 6%, Great Britain - 3%, and in Italy and Japan - only 0.3%. In Russia, 10% of the total mass of MSW is classified as hazardous waste. In many countries of the world, the amount of hazardous waste is steadily increasing (Table 8.2).

Table 8.2

Hazardous waste production in various countries

	Hazardous waste, thousand tons
early 80s	late 80s
Germany (without the GDR) Great Britain World (overall)

On the territory of Russia there are so-called chemical "traps", that is. long-forgotten landfills of hazardous waste, on which residential buildings and other objects were built over time. Over time, they make themselves felt by the appearance of strange diseases among the local population, but their registration has not yet been carried out. Accounting for such burials in the United States showed that there are at least 32 thousand potentially dangerous; in Germany, about 50 thousand such sites were identified, in the Netherlands - 4000, and in small Denmark - 3200.

Approximately 85 sites of nuclear explosions for peaceful purposes carried out on the territory of Russia can be similar traps. Since the 1960s, 47 underground nuclear explosions have been carried out in the Caspian region for technical purposes (deep seismic sounding, to increase oil recovery, to create underground tanks in salt domes, etc.).

Waste radioactive are by-product biologically or technically harmful substances that contain radionuclides formed as a result of human activities. Radioactive waste (RW) is dangerous primarily because the radionuclides contained in it can disperse in the biosphere and cause various genetic changes in the cells of living organisms, including humans. They are classified according to various criteria: state of aggregation, half-life, specific activity, radiation composition, etc. .

Among the radioactive waste in terms of aggregate state, the most common are liquid, which occur at nuclear power plants, at radiochemical plants, and in research centers. The amounts of solid radioactive waste are also significant, in particular, in nuclear power plant reactors with a total electric power of 1 GW, 300-500 m3 of solid waste is generated per year, and from the processing of irradiated fuel another 10 m3 of high-level, 40 m3 of medium-level and 130 m3 of low-level waste.

Currently landfills for solid waste disposal must be designed and equipped in accordance with the following rules:

· new landfills should be created on elevated sites with deep groundwater; often soil is removed from the top of the hill, which is subsequently used for backfilling waste;

· around the perimeter of the landfill, ceramic pipes should be dug in to collect water and leachate, and its bottom should be covered with a waterproof layer of clay or plastic at least 20 cm thick; a layer of coarse gravel and a layer of porous soil are laid on top of it; all this is designed to ensure that the filtrate, having reached the impervious layer, flows through the gravel into the collector system, and then undergoes appropriate processing (Fig. 4);

· a layer of gravel surrounding the landfill also serves to divert the resulting methane;

· layer-by-layer stacking of waste continues until the burial looks like a pyramid; with this form, infiltration is minimized, and consequently, the leaching of substances from the garbage;

Finally, monitoring wells are installed along the perimeter of the landfill for periodic monitoring of the quality of groundwater.

A more expensive way to dispose of solid waste is to burning to receive electricity. In this case, modern gas cleaning equipment* should be used to prevent air pollution. Of particular concern is the fact that the incineration of MSW generates dioxins are extremely hazardous and persistent substances capable of bioaccumulation and bioconcentration. It should be noted that this approach does not completely solve the problem of disposal, since the ash remaining after incineration is about 10-20% of the initial volume of garbage.

Municipal landfills are not allowed to dispose of hazardous materials. chemical substances. If it is impossible or inexpedient to process them, they resort to burial.

There are three most common disposal methods for hazardous waste. The first of these provides injection of liquid waste into a deep well drilled below the level of impervious rocks. In this case, after sealing the well, conditions are created for long-term storage of pollutants.

The second method is the storage of liquid (non-volatile) waste in special settling ponds to prevent leakage of contaminants.

The third, most expensive, method is used for the disposal of very toxic and radioactive substances. It provides for the construction of special burial grounds including waste storage tanks, protective rooms, monitoring system, alarms and other precautions.

However, none of these methods can guarantee 100% isolation and security. Therefore, it is necessary to strive to minimize the amount of waste generated.

Now hopelessly outdated methods of radioactive waste management are used: high-level waste is concentrated and isolated, medium- and low-level waste is diluted and sprayed, polluting the environment. The most acceptable option for solving the problem of waste is to bury them to a considerable depth in the earth's crust. Thus, high-level waste is most often stored in surface or underground containers (mines, galleries, mainly in rock salt, wells in rocks, etc.). For example, in the United States, radioactive waste is buried in salt mines and rocks, in Sweden - in underground storage facilities in granites, where containers with waste are stored in large bathrooms filled with distilled water, etc. In our country, waste waste is concentrated at nuclear power plants or in separate storage facilities where the "fuel" is aged, significantly reducing its radioactivity. On the territory of Russia there are 15 landfills for RW disposal.

In Russia there are large centers for the disposal of liquid RAO and their burial (Chelyabinsk-65e Krasnoyarsk-26, etc.). Unfortunately, the existing methods of neutralization (cementing, vitrification, bituminization, etc.), as well as the burning of solid RAO in ceramic chambers (NPO "Radon") radioactive waste poses a significant danger to the environment. So, at the Mayak training ground (near Chelyabinsk), up to. 100 million curies of liquid radioactive waste, some of which are simply dumped into water bodies: more than 3 million hectares of land have already been polluted. This area has become a zone of ecological disaster, where oncological diseases have increased by 2 times, the incidence of childhood leukemia by 66%, etc.

Storage tanks are used to prevent contamination of groundwater and surface water sources. They use impervious devices that ensure the reliable operation of structures and exclude the leakage of waste fluid. The type of reservoir is determined by the nature of the wastewater or solid waste.

There are accumulators of liquid single-phase effluents: storage ponds, evaporation ponds, settling tanks, filtration fields; accumulators of two-phase effluents: tailing and sludge storages, hydraulic ash dumps and solid waste accumulators: ash dumps, sludge collectors, etc.

Accumulators of liquid single-phase drains. Intensely colored industrial wastewater with a strong odor, containing a large number of salts. With a high content (more than 100 g/l) of homogeneous salt in the waste water, it is advisable to evaporate it in order to extract the salt. Industrial wastewater containing a large amount of organic substances that cannot be extracted and used, and waste acids (sulfuric, nitric, hydrochloric) in various proportions, is also sent to these accumulators. In some cases, it is possible to direct wastewater containing only mineral salts into storage tanks, the extraction of which, despite their high concentration, is impractical due to the impossibility of application.

In order to avoid overfilling, it is impossible to send slightly contaminated effluents to storage tanks, which are subject to unimpeded or after treatment at treatment facilities, discharge into a reservoir, as well as. too concentrated wastewater, such as 20% sulfuric acid.

The scheme of the storage pond-evaporator is shown in fig. 7.3. It is based on an embankment dam, an impervious curtain made of a waterproof material, buried to a layer of clay. The design of the pond to a large extent depends on the terrain, geological structure and hydrological conditions of the area. Depending on the relief, ponds can be ravine, flat, floodplain, slope and pit.

Rice. 8.6. Storage pond-evaporator: 1 - embankment dam; 2 - the maximum calculated level of effluents; 3 – water horizon (HW) in the lake-saline marsh before the construction of the pond; 4 - impervious curtain of bentonite clays; 5 - clays; 6 - sands; 7 - loams; 8 - soil

Ravine Ponds they are placed in gullies and ravines with a blocking dam in their lower part and with special spillway structures designed to pass the natural runoff of rain and melt water. Discharge devices are made in the form of a bottom pipe or tunnel. Plains drives arrange on flat areas, dike them around the entire perimeter, or in artificially created recesses-capacities. floodplain ponds are built in the floodplains of the rivers by embanking a section of three sides. In the same way, drives are created on slopes. Pit storages arrange in the workings of old quarries or reserves.

Soils have different throughput capacity, characterized by the filtration coefficient Kf . The filtration coefficient is the filtration rate through a unit cross section of the soil with a hydraulic gradient, equal to one. The filtration coefficient is the main characteristic of the water permeability of soils. In table. 8.3 shows the values ​​of Kf for various soils.

Table 8.3

Physical characteristics of soils used for the construction of reservoirs

	Bulk density, g/cm3	Density, g/cm3		Water permeability
Loam				permeable Semi-permeable Waterproof

The most radical means used to protect groundwater and reservoirs from pollution are the interception of filtered effluents by drainage and the installation of impervious curtains and screens.

Anti-seepage devices are designed to reduce seepage through a dam or dam and increase its stability, eliminate dangerous filtration deformations of the soil and completely retain sewage water. For their construction, coatings with poorly permeable soils (clay, loam), bitumen, concrete, polymer films, etc. are used.

Accumulators of two-phase drains. Two-phase effluents are aqueous suspensions of mineral and organic substances of various compositions. The concentration of the solid phase in them ranges from 20 to 100 g/l. This, as a rule, is waste from the processes of purification and preparation of waste and natural waters, the main technological processes. They are sent to a tailing dump or a sludge dump. In these accumulators, the sediment is separated and clarified water is obtained. tailings is a piece of terrain fenced off by a dam or dam (Fig. 8.7). A dam or dam is built in bulk or alluvial way.

Rice. 8.7. Tailings dam: 1 - dam of the first stage; 2 - secondary dams; 3 - dam of the second stage

As the fenced-off area fills up, secondary dams are built. These dams are built in bulk from imported materials. At high pressures on the dams and the presence of strongly filtering gr. high fur boots arrange discharge drainages. As pulp is supplied to the tailings, the water level in their clarification ponds rises all the time, the location of the pond and its size change within the storage facilities.

Tailings dumps occupy vast areas, measured in hundreds of hectares; their depth reaches hundreds of meters, and the depth of the water layer, depending on the conditions of pulp supply and clarified water intake, is 0.5-1.5 m.

Sludge storage- large earthen ground structures with a volume of up to tens of millions of cubic meters and a depth of up to 50 m, their service life exceeds 10 years. They are created in the water supply and sewerage system of chemical and petrochemical enterprises. They are placed on flat flat areas of the terrain (in floodplains, on terraces) and bunded from all sides. or partially in areas of local relief depression.

Sludge storages are also located in gentle ravines and gullies. Embankment dams and blocking dams are built in bulk from loamy materials. You can also use the sludge washed into the sludge storages. The sludge pulp is supplied to the sludge storages according to the same schemes as the tailing pulp to the tailings.

According to the conditions of waste storage, sludge storages are divided into alluvial and liquid. For bulk sludge storages, earthen dams are preliminarily built to the full height of the designed tank or to a part of this height. Fill dams are most often erected, and fill dams are less often provided.

A road and slurry pipelines are laid along the crest of the dam. The crest of the dam should have a protective coating and a system of ditches for organized collection and disposal of surface water. Sludge storages can occupy a different area and working volume. On average, the area of ​​the sludge reservoir is 10-20 ha, the amount of sludge discharged, ths. t per year.

Solid Waste Accumulators designed to collect sludge from general plant treatment facilities, clean brines, slag materials, ash, etc. These earthworks are similar to tailings and sludge storages.

On fig. 8.8 shows a diagram of a sludge collector. The land area occupied by it is about 5 hectares, depth is 10 m. In order to prevent storm and melt water from entering the sludge collector from the catchment area, in places where surface water can be directed, an enclosing embankment 4 m wide along the ridge is arranged. To prevent contamination of groundwater with excess moisture sludge, provide an impervious screen. The same screen is arranged on the leveled surface of the sludge.

Rice. 8.8. Solid waste sludge accumulator: 1 – bowl; 2 - overpass; 3 – storage slopes; 4 - forest plantation; 5 - drainage ditch

The screens consist of two layers: the lower one (two layers of polymer film 0.2 mm thick) and the upper one (ground-polymer layer 0.6 mm thick). The soil-polymer layer is obtained by spraying a solution of synthetic fatty acids heated to 80°C over the prepared soil layer.

For environmental purposes, to control the operation of the impervious screen and the quality of groundwater in the area of ​​the sludge dump, wells are drilled to take water samples for chemical analysis.

In order to prevent dusting of the upper dried layer of sludge and to create a natural fence around the area of ​​the sludge reservoir, a forest belt of trees and shrubs is provided. In order to prevent domestic animals from entering the territory of the sludge collector, it is fenced with barbed wire on reinforced concrete posts.

The sludge is transported to the sludge accumulator after being processed at the station for mechanical dehydration of general plant treatment facilities by dump trucks, followed by dumping into the sludge accumulator from overpasses and the crest of the enclosing embankment. After filling the sludge collector and installing the upper screen, a layer of local sandy soil 0.6 m thick is poured on top and a layer of local soil and vegetable soil 0.5 m thick is poured over it. After the above work is completed, the sludge collector site is returned to agricultural use.

* usually expressed in mg per kg of soil.

* The cost of such equipment sometimes reaches half of all costs for the construction of the plant.

To protect soils, forest lands, surface and ground waters from solid and liquid wastes, the collection and storage of industrial and domestic wastes is currently widely used. Landfills and landfills for the processing and disposal of industrial waste have become negative companions of large industrial cities.

Landfills accept: arsenic containing inorganic solid waste and slimes; waste containing lead, zinc, tin, cadmium, nickel, antimony, bismuth, cobalt and their chemical compounds, galvanic production waste; organic solvents; organically combustible (cleaning materials, rags, resins, plastic scraps, etc.), oil products (waste), radioactive waste. The landfill should include a plant for the incineration of organic and disposal of toxic waste. Landfills must have the necessary sanitary protection zones.

The norm of chemical contamination of soils is set according to the maximum permissible concentrations (MPC) for water, air and soil.

A radical solution to the problem of protecting the lithosphere from industrial waste is the widespread use of waste-free and low-waste technologies and industries.

An example of recycling waste from the woodworking industry for the production of building materials is:

production of arbolite;

· production of slag-sawdust blocks;

· production of building wall blocks from burnt earth, cement and sawdust.

34. Fundamentals of placement, design and reclamation of municipal solid waste (MSW) landfills. Currently, the facility (landfill, landfill, etc.) for storage and disposal of waste is a complex engineering complex that ensures the safety of the functioning of industrial and residential areas.

The selection and justification of a site for the placement of a landfill for storage and processing of waste is the most important stage design work. Landfills are located outside cities and other settlements, while sanitary requirements for placement must be observed.

The most favorable sites for landfills for the disposal of solid waste are considered to be exhausted quarries, ravines with the provision of protective measures.

When designing solid waste disposal facilities, it is necessary to analyze possible hazard scenarios:

during operation;

In the process of accumulation

long-term, not foreseen in the design.

All sanitary landfills are divided into the following types:

MSW landfills;

· landfills for hazardous waste;

polygons for construction waste;

landfills for industrial waste.

When designing landfills, the following criteria should be taken into account:

protection of groundwater;

filtrate management;

protection of surface waters;

landfill gas control;

· exploitation;

Efficient use of space

stability of slopes and slopes of the array.

Particular attention in the project should be paid to the design of the underlying screen, leachate collection system, landfill gas collection system; surface coating; monitoring, stormwater management, support services.

When designing landfills, it is necessary to provide next activities for the rehabilitation of the territory, which should include:

landfill closure technology;

Landscape solutions

active use of the territory by the population;

cultural and historical significance.

35. Describe the essence of the technological design of TGV (TGVS) systems. Composition and purpose of POS and PPR. The peculiarities of heat and gas ventilation systems are that they include devices that operate under pressure above atmospheric and are located at a height or laid in various soil environments at the intersection with other engineering communications. At the same time, when laying gas pipelines, installing gas control systems and maintaining them, one has to deal with gas-air explosive atmospheres.

All these features impose an increased responsibility in terms of safety on workers and engineers, who must be prepared to work safely in high-risk conditions.

One of the most important issues for ensuring safety during the construction of DHWs is the correct organizational and technical preparation.

Construction organization projects are carried out by a specialized design organization on the instructions of the customer, and PPR - by the contractor or general contractor.

In the PPR, safety issues are developed in detail, where all safety measures are justified by engineering calculations based on norms and rules.

Safety issues should be included in the flow charts for installation and other work during the installation of DHW. Technological cards must necessarily be drawn up for complex and dangerous work, as well as for work performed by new methods.

36. Describe the features of excavation and work at height. Definition of permanent hazardous areas for these types of work. One of the most important issues for ensuring safety during the construction of DHWs is the correct organizational and technical preparation.

This preparation includes two stages: organizational and technical.

At the stage of organizational preparation, a construction organization project (POS) is developed, and at the technical stage, a project for the production of works (PPR).

The radius of the danger zone during the operation of the jib crane, taking into account the departure of the load when the lines break, is:

Where r is the maximum reach of the boom, m;

s – possible departure of cargo, m;

h is the height of a possible fall, m;

l is the length of the sling branch, m;

α is the angle between the vertical and the branch;

a is the distance from the outer edge of the load to its center of gravity, m.

Particular attention in the production of earthworks should be paid to the resistance to collapse of loose slopes. So, the angle of repose ( φ ) for dry sand 25 ... 30º, wet sand - 20º, dry clay - 45º and wet clay - 15º. From right choice the angle of slope depends on the safety of excavation and work inside it.

Based on the stability of soils, the critical height of a vertical wall without slopes is determined by the formula

H cr = 2C cos φ / ,

where H cr is the critical height of the vertical wall;

C - soil cohesion, t / m 2;

is the soil density (φ is the angle of internal friction, which is determined according to the rules of soil mechanics).

37. Means of ensuring safety in the production of earthworks.

At the stage of organizational preparation, a construction organization project (POS) is developed, and at the technical stage, a project for the production of works (PPR).

Particular attention in the development of PPR should be paid to the safety of earthworks. This is due to the fact that earthworks in the construction of heating systems and gas pipelines are one of the main ones.

Earthworks can only be started if there is a PPR with the coordination of pipeline laying routes with the relevant organizations.

When constructing the vertical walls of pits and trenches in soft soils, it is necessary to provide for their fastening.

The fastening system is calculated on the active pressure of the soil. In fastenings of the spacer type, fastening boards, racks and spacers are subject to calculation. Struts are calculated for strength and stability according to the rules of structural mechanics.

When installing ventilation systems and when laying external pipelines and during other installation work, scaffolding and scaffolding are used. Most often, for installation work, scaffolding is used on boltless joints, where tubes are welded to the posts, and hooks from round steel bent at right angles. With this method of fastening, the installation of each horizontal element of the scaffolding is reduced to the introduction of hooks into the corresponding tubes on the racks until it stops.

Most often, during the construction of DHW, mobile collapsible scaffolds are used (GOST 28012 - 89). Due to some features, these scaffolds are used only indoors in the presence of a hard floor covering. In many cases, when laying communications along the walls, hinged scaffolds are used.

38. Means of ensuring safety when working at height during the construction and repair of TGVS One of the most important issues for ensuring safety during the construction of DHW is the correct organizational and technical preparation. This preparation includes two stages: organizational and technical.

At the stage of organizational preparation, a construction organization project (POS) is developed, and at the technical stage, a project for the production of works (PPR).

Particular attention in the WEP should be paid to the definition and limitation of permanent hazardous areas. These zones include dangerous zones during the operation of tower and jib cranes, during the installation of ventilation and gas supply systems located at a height. This is due to the possibility of breaking the mounting slings and flying off the load to the side when it falls.

When working at height, an open area located under the work area is considered dangerous, the boundaries of which are determined by the horizontal projection of the work area increased by a safe distance p = 0.3 H, where P is the distance of the axis of the horizontal projection boundary, in meters , and H is the height at which the DHW installation is performed.

Most often, during the construction of DHW, mobile collapsible scaffolds are used (GOST 28012 - 89). Hanging scaffolds are designed to work at heights. These include hinged cradles, GOST 27372 - 87.

Scaffolds on telescopic towers are used both for indoor work at height and for outdoor installation work, GOST 28347 - 89.

When working on telescopic towers, installers are equipped with safety belts, which are attached to a steel safety rope using safety catchers.

39. Describe the basic safety requirements when working with a manual electrified device. In the construction and repair of DHWS in many cases, small-scale mechanization tools are used. These include: mechanized tools - a drilling machine, electric saws, electric shears, pneumatic hammers, grinders and sharpeners, mobile compressors, riveting devices.

The main safety requirements for the operation of hand-held electrified tools are:

exclusion of the possibility of applying mechanical injuries;

· electrical safety;

· noise safety;

vibration safety.

The measures that ensure safety when working with a hand-held electrified tool are set out in the tool passports and safety instructions drawn up on the basis of SNiP 12 - 03 - 2001 “Labor safety in construction. Part 2. Construction production»

40. Name the main causes of electrical injuries during the construction and repair of DHW. And on what factors does it depend.Injury statistics show that the number of injuries caused by the action of electric current is low - 1 ... 2% of the total, however, fatal accidents are the largest. At the same time, 80% of them fall on electrical installations with voltages up to 1000 V.

The causes of electrical injury (electric shock to the human body) are:

intentional work under stress;

erroneous exposure to voltage;

Convergence or whipping of wires;

malfunction of electrical equipment;

Violation of the security zone of high-voltage lines and transportation of oversized cargo;

absence or irregularity of instruction;

Lack of protective equipment

Illegal combination of professions.

The external manifestation of electrical injuries are:

metallization of the skin surface on the human body.

The danger of current exposure to a person depends on such factors:

the magnitude of the current (the main factor);

the duration of the current;

the path of current in the human body;

type and frequency of current;

individual qualities of a person.

The most dangerous is alternating current with a frequency of 50 ... 500 Hz. A person can independently free himself from the action of an alternating current of 10 ... 15 mA, and with a direct current - 20 ... 25 mA. A current with a voltage of 12 ... 36 V is considered relatively safe for humans.

41. Specify the measures to eliminate the dangers of electric shock to a person. Injury statistics show that the number of injuries caused by the action of electric current is low - 1 ... 2% of the total number, however, fatal accidents are the largest. At the same time, 80% of them fall on electrical installations with voltages up to 1000 V.

using organizational and technical measures.

42. Ways and methods of ensuring safety in electrical installations. Particular attention in ensuring electrical safety at the construction site should be paid when working with temporary electrical wiring, which must be carried out with an insulated electrical wire and suspended on a cable on strong supports at a height of at least 2.5 m above the workplace, 3.5 m above the aisles and 6.0 m above the driveways. Portable lamps at the construction site are powered by a voltage of no higher than 42 V, and in damp areas, boilers, wells, metal tanks, etc. - no higher than 12 V.

To eliminate the danger of electric shock to a person when faulty and poorly insulated current-carrying parts of electrical equipment are connected to the ground, protective grounding is used.

The essence of protective grounding is to reduce the voltage on the electrical equipment case when a current is shorted to it.

In three-phase networks with a grounded neutral with a voltage of up to 1000 V, protective zeroing is arranged. It should be noted that it does not provide reliable protection.

If it is impossible to ground the equipment (frozen, rocky soils), in addition to protective grounding, a protective shutdown is used, the essence of which is to quickly automatically turn off the damaged section of the electrical network during a single-phase short circuit of current-carrying parts to the housing.

The electrical safety of electrical installations can be ensured in several ways:

designing safe and reliable electrical installations;

Providing protection by technical means;