Contamination of wasps with solid waste and methods of their processing. Recycling household waste as a business

The current system for handling them in our country was formed back in Soviet times. The main method by which solid household waste is currently disposed of is landfill disposal. At first glance, it is the cheapest, but when making calculations, they often forget to take into account that in addition to the costs of maintaining the site, there are also costs for decommissioning, compensation for damage to nature and irretrievable losses of resources.

As an alternative, in some megacities, solid waste is disposed of by burning it in specialized waste disposal facilities. However, this method has a number of disadvantages, one of which is that the waste disposal plant is also a source for the surrounding area. True, to be fair, it is worth noting that there are combustion technologies that minimize the formation of dioxins. In addition, as a result of this method, the volume of waste is reduced by ten times and it is possible to produce heat or electricity, and the resulting slag is recycled into industry.

Also disposed of through aerobic biothermal composting. Before this, they are sorted. Everything that is formed as a result of consumption can be divided into three main groups. The first is (solid waste), which can be processed into useful materials and receive a certain income from their sale, which allows you to compensate for the costs. The second is biodegradable waste; it can be turned into compost, although the costs associated with this are difficult to compensate. The third is non-recyclable solid waste; solid waste of this group is disposed of in various ways, depending on their specific composition.

Aerobic biothermal composting is considered the most promising technology today. With its help, solid waste is converted into a harmless state and becomes compost, which is a fertilizer that contains microelements, phosphorus, nitrogen, and potassium. Such disposal of solid waste allows you to return it back to natural waste in nature.

The use of mass processing of solid waste using the latter method is difficult today for a number of reasons: imperfect legislation, lack of a unified information base for all types of solid waste, weak control over compliance with regulations, and insufficient funding. If we turn to experience developed countries, then it becomes clear that it is possible to establish it properly only if you approach this issue systematically. All processes related to waste disposal should be configured and debugged. It is necessary to cover everything in its entirety, including sources of waste generation (organizations and people), transportation, storage, sorting, processing, and final disposal. The public and each individual citizen should be actively involved in solving this problem. And most importantly, we need an effective mechanism for economic stimulation of rational and careful attitude to what nature has given us.

The most common method of solid waste disposal is incineration followed by disposal of the resulting ash in a special landfill. There are quite a few waste incineration technologies - chamber, layer, fluidized bed. Garbage can be burned mixed with natural fuel.

Thermal processing: process, advantages and disadvantages

Combustion method(or in general view thermal methods of solid waste disposal) has both undoubted advantages (the heat of combustion of solid waste can be used to generate electricity and heat buildings, reliable waste disposal) and significant disadvantages. Required good system cleaning of flue gases, since when burning solid waste, hydrogen chloride and fluoride, sulfur dioxide, nitrogen oxides, as well as metals and their compounds (Zn, Cd, Pb, Hg, etc., mainly in the form of aerosols) are released into the atmosphere and, What is especially important is that during the combustion of waste, dioxins and biphenyls are formed, the presence of which in the exhaust gases significantly complicates their purification due to the low concentration of these highly toxic compounds.

A type of combustion process is pyrolysis - thermal decomposition of solid waste without access to air. The use of pyrolysis can reduce the impact of solid waste on environment and receive such healthy products, How flammable gas, oil, resins and solid residue (pyrocarbon).

The process of high-temperature processing of household and industrial waste in a bubbled slag melt is widely advertised (Fig. 1). The main unit of the technological scheme is a bubble furnace, the design of which was developed in collaboration with specialists from the Stalproekt Institute (Moscow).

The furnace is simple and has small dimensions, high performance and high operational reliability.

The process is carried out as follows. Household waste is fed into the loading device periodically. The pusher throws them into a slag bath, blown with oxygen-enriched air. In the bath, waste is quickly immersed in an intensively mixed foam melt. The slag temperature is 1400 – 1500 °C. Due to intense heat transfer, waste undergoes high-speed pyrolysis and gasification. Their mineral part dissolves in the slag, and metal objects melt, and liquid metal falls onto the floor. With low calorie waste for stabilization thermal regime as additional fuel, it is supplied to the furnace in small quantities thermal coal. Can be used instead of coal natural gas. To obtain slag of a given composition, flux is loaded.

The slag is discharged from the furnace through a siphon continuously or periodically and sent for processing. Chemical composition slag can be adjusted within wide limits, obtaining compositions suitable for the production of various building materials– stone casting, crushed stone, fillers for concrete, mineral fiber, cement.

The metal enters the siphon through the overflow and is continuously or in portions poured into a ladle and then transferred for processing or poured into pigs directly at the furnace or granulated. Combustible gases - products of pyrolysis and gasification of waste and coal, released from the bath - are burned above the bath by supplying oxygen-enriched air or pure oxygen.

High-temperature (1400 – 1600 °C) furnace gases are sucked by a smoke exhauster into the steam boiler for cooling and beneficial use their energy. The boiler carries out complete combustion of gases. The cooled gases are then sent to the purification system. Before they are released into the atmosphere, they are cleaned from dust and harmful impurities. High temperatures process, a rational combustion scheme, consisting of a combination of the redox potential of the gas phase and temperature regime, cause low levels of nitrogen oxides (NOx) and other impurities in flue gases.

Due to high-temperature combustion, flue gases contain significantly less organic compounds, in particular dioxins.

The transfer of alkali and alkaline earth metals into the vapor-gas phase under process conditions promotes the binding of chlorine, fluorine and sulfur oxides into safe compounds that are captured during gas cleaning in the form of solid dust particles. Replacing air with oxygen allows you to reduce the volume of flue gases by 2–4 times, facilitate their cleaning and reduce discharge toxic substances into the atmosphere. Instead of large quantity bottom ash (up to 25% during conventional combustion), containing heavy non-ferrous metals and dioxins, forms inert slag, which is a raw material for the production of building materials. Dust carried out from the furnace with flue gases is selectively captured at different cleaning stages. The amount of dust is 2–4 times less than when using traditional ovens. Coarse dust (up to 60%) is returned to the furnace, fine dust, which is a concentrate of heavy non-ferrous metals (Zn, Pb Cd, Sn, etc.), is suitable for further use.

Modern methods of thermal processing of solid waste

The Gintsvetmet Institute, together with other Russian organizations, has developed a technology for thermal processing of solid waste in a bubbled slag melt. Its main advantage is the solution to the current global dioxin problem: already at the outlet of the bubbling unit there are practically no highly toxic compounds (dioxins, furans, polyaromatic hydrocarbons). At the same time, there are now a number of domestic and foreign methods for thermal processing of solid waste, which are at different stages of development. The table shows the main indicators of thermal methods for processing solid waste, most known to ecologists and specialists in the disposal of such waste. These methods have either already been industrialized or have undergone large-scale testing. The essence of the processes used:

CD process– combustion of solid waste in a furnace with grates (KR) or a boiler unit on grates of different designs;
CS process– combustion of waste in a fluidized bed (FB) of inert material (usually sand of a certain size);
Pyroxel process– electrometallurgical, including drying, pyrolysis (combustion) of waste, processing of mineral combustion residue in molten slag, as well as dust and gas purification of flue gases;
process in a unit such as a Vanyukov furnace (PV)– melting in a bubbled melt;
process developed at the Institute chemical physics RAS - burning– gasification of waste in a dense layer of lump material without its forced mixing and movement;
Thermoselect process– combined, including the stages of waste compaction, pyrolysis and high-temperature gasification (to produce synthesis gas, inert and some mineral products and metals);
Siemens process - pyrolysis– combustion of pyrogas and separated carbonaceous residue using non-oxygen-enriched blast.

Combustion of solid waste in furnace-boiler units (KR process) due to the relatively low temperatures(600 – 900 °C) practically does not solve the dioxin problem. In addition, this results in the formation of secondary (solid unburned) slags and dust, which require separate processing or are sent for disposal with subsequent negative consequences for the environment. These shortcomings are to a certain extent inherent in the QE process. Here we add the need to prepare raw materials for processing in order to maintain the particle size distribution.

The disadvantages of the process developed by the Institute of Chemical Physics of the Russian Academy of Sciences include:

the need to sort and crush waste to certain sizes; addition and subsequent separation of coolant of a given granulometric composition;
the need to develop an expensive flue gas purification system - synthesis gas, which is a mixture of carbon monoxide and hydrogen.

The process of melting solid waste in a bubbled melt (in a PV furnace) should be noted (in addition to dioxin safety) two more advantages: relatively high specific productivity and low dust removal. These indicators are due to the bubbling effect (intensive gas purging of the melt bath and splash saturation of the furnace working space above the bath). An important positive factor is the presence of industrial experience in their operation at non-ferrous metallurgy enterprises in Russia and Kazakhstan. In general, it can be stated that the latest domestic development is superior in key indicators to other domestic and foreign technologies for processing solid waste and is a definite scientific and technical breakthrough in solving the global environmental problem.

Currently, one of the authors, under the guidance of the thesis project director, is developing a design for a solid waste landfill for the station. Arkhonskaya North Ossetia-Alania, where the issue of unsatisfactory management of solid household waste is acute. When developing this project, the outlined solutions for the management of solid waste and, first of all, the preliminary sorting of this waste and the extraction of polymer and other waste for further processing will be taken into account.

Biothermal processing of solid waste: Aerobic fermentation

From biothermal methods in practice greatest distribution received aerobic fermentation, which is often called composting (after the name of the final product of fermentation - compost, used in agriculture).

Fermentation is a biochemical process of decomposition of the organic part of waste by microorganisms. In biochemical reactions, organic material, oxygen and bacteria (saprophytic aerobic microorganisms present in MSW in sufficient quantities) interact, and carbon dioxide, water and heat are released (the material self-heats to 60-70°C). The process is accompanied by the synthesis of humus. Reproduction of microorganisms that destroy waste is possible at a certain ratio of carbon and nitrogen.

The best contact between organic matter and microorganisms is ensured by mixing the material, as a result of self-heating of which during the fermentation process the majority of pathogenic microorganisms, helminth eggs, and fly larvae are destroyed.

According to the results of research by English specialists, at the initial stage of fermentation, mineralization of the mixture occurs, as evidenced by a decrease in the total carbon content organic matter and humic acids. The resulting biomass has a high degree of polymerization and is characterized by a significant (compared to soil) nitrogen concentration. During the fermentation process, the content of phenolic groups in the biomass decreases and the content of HOOC and C=0 groups increases.

As a result of the completed fermentation process, the mass of biodegradable material is halved and a solid, stabilized product is obtained.

Composting after disposal of solid waste has developed in world practice as an alternative to incineration. The environmental goal of composting can be considered the return of part of the waste to the natural cycle.

Composting of solid waste developed most intensively from the late 60s to the early 80s, mainly in countries Western Europe(Italy, France, Netherlands). In Germany, the peak of plant construction occurred in the second half of the 80s (in 1985, 3% of solid waste was processed into compost, in 1988 - about 5%). Interest in composting increased again in the mid-90s based on the involvement in processing not of solid waste, but of selectively collected food and plant waste, as well as waste from the gardening and park complex ( thermal processing of this waste is difficult due to high humidity, and burial is associated with the uncontrolled formation of leachate and biogas). In European practice, by 2000, about 4.5 million tons of waste were processed annually using aerobic fermentation at more than 100 plants (of which 60 plants were built in 1992-95).

In the CIS countries, direct composting of initial solid waste is used at nine plants: in St. Petersburg (the first plant in former USSR, built in 1971; at the end of 1994, a second plant was put into operation in St. Petersburg), Nizhny Novgorod, Minsk and Mogilev, Tashkent, Alma-Ata, Tbilisi and Baku (all plants were designed by the Giprokomunstroy Institute, Mogilev - by the Belkommunproekt Institute), In In 1998, a plant was put into operation in Togliatti, where preliminary but ineffective sorting of solid waste was implemented.

It should be noted that due to the heterogeneous composition of waste, direct composting of solid waste is impractical, since the resulting compost is contaminated with glass and heavy metals (the latter, as noted, are contained in hazardous household waste - waste galvanic cells, fluorescent lamps).

In the first mechanized industrial plants, solid waste was most often composted in piles, periodically subjecting the material to tedding.

Currently, three methods of aerobic fermentation are most common in industry:

fermentation (composting) in biodrums;
tunnel composting (fermentation);
fermentation (composting) in a holding pool.

In the CIS since 1971, composting in bio-drums has been practiced exclusively (in the mode of loading and unloading material, the rotation speed of the bio-drum is 1.5 min1, the rest of the time 0.2 min1). In Russia (plant in Togliatti), based on cement kilns, biodrums are produced in two sizes - 36 and 60 m long; diameter of biodrums - 4 m.

The environment has always been a source of resources for humanity, but for a long time its life activity did not have a noticeable impact on nature. Only since the end of the last century, under the influence economic activity Noticeable changes in the Earth's biosphere began to occur. They have now reached alarming proportions.

The scale of the problem

Rapid growth in population and consumption levels natural resources, modern rates of material production lead to thoughtless treatment of nature. With this attitude, a huge part of the resources taken from nature is returned to it in the form of waste, harmful and unsuitable for further use.

Scientists estimate that 5 tons of garbage are generated every day in the world, while its amount increases annually by 3% by volume. The accumulation of household waste on the surface is harmful surrounding nature, polluting water, soil and atmosphere and threatening the existence of all life on the planet. Therefore, one of the important issues around the world is the disposal of household waste.

Classification of household waste

Household waste can be classified according to several criteria.

Thus, according to its composition, household waste is conventionally divided into biological residues and non-biological waste (garbage).

rats;
cockroaches

Cockroaches can be a carrier different types diseases

Non-biological waste includes:

paper;
plastic;
metal;
textile;
glass;
rubber.

The process of decomposition of this waste can last about 2-3 years and in most cases is accompanied by the release of toxic substances, causing harm to the environment and humans.

By state of aggregation waste is divided into:

hard;
liquid;
gaseous;
pastes;
gels;
suspensions;
emulsions.

By origin, waste is divided into:

Industrial – a type of household waste resulting from production.
Construction - are formed during construction and installation work, repair of roads, buildings, as well as during their demolition.
Radioactive waste.
Municipal solid waste (MSW) is generated in the residential sector, trade enterprises, educational, healthcare and social cultural facilities.

These are goods that have lost their consumer properties over time and turned into garbage, and also include road and yard waste as solid waste.

The most significant part of household waste is MSW. For each type of waste there are special waste disposal methods.

Waste recycling

The process of disposal of solid waste occurs in several stages:

collection;
transportation;
accommodation;
neutralization;
burial;
storage;
recycling;
disposal.

First of all, the process of getting rid of garbage involves its careful sorting. The task of preliminary waste sorting and recycling is greatly simplified separate collection garbage, promoted in most European countries.

Methods for disposal of solid household waste

There are various options for its destruction. Thus, the main way to dispose of solid waste is disposal at special sites (landfills).

At landfills, irrecoverable waste is destroyed - household waste is processed, as a result of which it almost completely ceases to exist as waste. The disposal method is not suitable for all types of solid waste, but only for non-combustible waste or for substances that emit toxic substances when burned.

The advantage of this method is that it does not require significant financial costs and the presence of large plots of land. But there are also disadvantages in using this method - the accumulation of gas during underground decay of waste.

Briquetting is a new, not yet widely used in practice, method of disposal of solid waste. It includes preliminary sorting and packaging of homogeneous waste into separate briquettes, and then their storage in specially designated areas (landfills).

Briquetting waste makes it possible to significantly save space

Garbage packaged in this way is pressed, which greatly facilitates its transportation due to a significant reduction in volume.

Briquetted waste is intended for further processing and possible application for industrial purposes. Along with this method, such as recycling of municipal solid waste, when briquetting they can be transported for burial or disposal by heat treatment.

In essence, this method is similar to the burial method, but in practice it has a number of advantages over it. The disadvantages of the method are that the heterogeneity of the waste emitted and preliminary heavy contamination in garbage containers and changes in some waste components create greater difficulty in briquetting.

And the high abrasiveness of components such as stone, sand and glass interfere with the pressing process.

Since these waste treatment methods have a number of disadvantages, despite their cheapness, the best option will be the complete disposal of waste during its processing into recyclable materials and fuel, as well as its possible reuse.

A new way to recycle waste

Garbage disposal

When recycling waste (Latin root utilis - useful), waste can later be used for various purposes.

Waste to be disposed of includes:

all types of metals;
glass;
polymers;
products from yarn and fabric;
paper;
rubber;
organic household and agricultural waste.

The most effective method of disposal today is recycling.

In other words, recycling is a special case of the concept of “disposal of solid household waste”.

When recycling, waste is returned to the process of technogenesis. There are two options for waste recycling:

Reuse of waste for its intended purpose after appropriate safe handling and labeling. For example, reusing glass and plastic containers.
Return of waste after processing to production cycle. For example, tin containers go into steel production, waste paper goes into paper and cardboard production.

Some types of waste that can no longer be used for their intended purpose are processed, after which it is more expedient to return them to the production cycle as secondary raw materials. Thus, part of the waste can be used to generate thermal and electrical energy.

In addition to those already listed, solid waste disposal can be carried out by several other methods. Each of them is applicable to a specific type of waste, and has its own advantages and disadvantages.

Thermal waste treatment

Thermal processing refers to several methods:

burning;
low temperature pyrolysis;
plasma treatment (high temperature pyrolysis).

The method of simple waste incineration is the most common and one of the cheapest methods of dealing with waste. It is during combustion that large volumes of waste are disposed of, and the resulting ash takes up less space, does not undergo decay processes and does not emit harmful gases into the atmosphere. It is non-toxic and does not require specially equipped burial sites.

The main thing about this method is that when burning waste, a large amount of thermal energy is released, which lately learned how to use it for autonomous operation of waste incineration enterprises. And its surplus is redirected to city stations, which makes it possible to provide electricity and heat to entire areas.

The disadvantage of this method is that during combustion, in addition to safe components, a saturated toxic substances smoke, which creates a dense curtain over the surface of the earth and leads to significant disruption of the ozone layer of the atmosphere, contributing to its thinning and the formation of ozone holes.

High and low temperature pyrolysis

- This process gasification of waste, which occurs at a melting temperature higher than in a conventional processing plant (over 900°C).

As a result, the output is a vitrified product, which is absolutely harmless and does not require further disposal costs. The design of this process makes it possible to obtain gas from the organic components of the waste, which is then used to produce electricity and steam.

The main advantage of this method is that it allows you to successfully solve the problem of environmentally friendly waste disposal without extra costs for preliminary preparation, sorting, and drying.

The advantages of low-temperature pyrolysis (temperatures from 450 to 900°C) are:

use for recycling of almost all types of household waste, carefully selected in advance;
obtaining pyrolysis oils used in the production of plastics;
release of pyrolysis gas suitable for further use.

In addition, there is a waste disposal method called composting. Since most of the waste consists of various organic residues, they are subject to rapid rotting in the natural environment.

The composting method is based on this property of organic substances. The process of composting not only gets rid of a huge part of the waste that pollutes the environment, but also produces substances useful for agriculture - fertilizers.

The presented waste disposal methods allow waste to be processed with the least negative impact on the environment.

Video: Modern approach to waste disposal

Thermal processing: process, advantages and disadvantages

Combustion method(or in general, thermal methods of solid waste disposal) has both undoubted advantages (the combustion heat of solid waste can be used to generate electricity and heat buildings, reliable waste disposal) and significant disadvantages. A good flue gas purification system is necessary, since when burning solid waste, hydrogen chloride and fluoride, sulfur dioxide, nitrogen oxides, as well as metals and their compounds (Zn, Cd, Pb, Hg, etc., mainly in the form of aerosols) are released into the atmosphere ) and, what is especially important, during the combustion of waste, dioxins and biphenyls are formed, the presence of which in the exhaust gases significantly complicates their purification due to the low concentration of these highly toxic compounds.

A type of combustion process is pyrolysis - thermal decomposition of solid waste without access to air. The use of pyrolysis makes it possible to reduce the impact of solid waste on the environment and obtain useful products such as flammable gas, oil, resins and solid residue (pyrocarbon).

The furnace is simple and has small dimensions, high performance and high operational reliability.

The process is carried out as follows. Household waste is fed into the loading device periodically. The pusher throws them into a slag bath, blown with oxygen-enriched air. In the bath, waste is quickly immersed in an intensively mixed foam melt. The slag temperature is 1400 – 1500 °C. Due to intense heat transfer, waste undergoes high-speed pyrolysis and gasification. Their mineral part dissolves in the slag, and the metal objects melt, and the liquid metal falls onto the hearth. When the caloric content of the waste is low, thermal coal is supplied in small quantities to the furnace to stabilize the thermal regime as additional fuel. Natural gas can be used instead of coal. To obtain slag of a given composition, flux is loaded.

The slag is discharged from the furnace through a siphon continuously or periodically and sent for processing. The chemical composition of the slag can be adjusted within wide limits, obtaining compositions suitable for the production of various building materials - stone casting, crushed stone, concrete fillers, mineral fiber, cement.

High-temperature (1400 – 1600 °C) furnace gases are sucked by a smoke exhauster into a steam boiler for cooling and beneficial use of their energy. The boiler carries out complete combustion of gases. The cooled gases are then sent to the purification system. Before they are discharged into the atmosphere, they are cleaned from dust and harmful impurities. High process temperatures and a rational combustion scheme, consisting of a combination of the redox potential of the gas phase and temperature conditions, determine the low content of nitrogen oxides (NOx) and other impurities in the flue gases.

Due to high-temperature combustion, flue gases contain significantly less organic compounds, in particular dioxins.

The transfer of alkali and alkaline earth metals into the vapor-gas phase under process conditions promotes the binding of chlorine, fluorine and sulfur oxides into safe compounds that are captured during gas cleaning in the form of solid dust particles. Replacing air with oxygen allows you to reduce the volume of flue gases by 2–4 times, facilitate their cleaning and reduce the discharge of toxic substances into the atmosphere. Instead of a large amount of ash residue (up to 25% during conventional combustion), containing heavy non-ferrous metals and dioxins, inert slag is formed, which is a raw material for the production of building materials. Dust carried out from the furnace with flue gases is selectively captured at different cleaning stages. The amount of dust is 2–4 times less than when using traditional ovens. Coarse dust (up to 60%) is returned to the furnace, fine dust, which is a concentrate of heavy non-ferrous metals (Zn, Pb Cd, Sn, etc.), is suitable for further use.

Modern methods of thermal processing of solid waste

CD process– combustion of solid waste in a furnace with grates (KR) or a boiler unit on grates of different designs;
CS process– combustion of waste in a fluidized bed (FB) of inert material (usually sand of a certain size);
Pyroxel process– electrometallurgical, including drying, pyrolysis (combustion) of waste, processing of mineral combustion residue in molten slag, as well as dust and gas purification of flue gases;
process in a unit such as a Vanyukov furnace (PV)– melting in a bubbled melt;
process developed at the Institute of Chemical Physics of the Russian Academy of Sciences - combustion– gasification of waste in a dense layer of lump material without its forced mixing and movement;
Thermoselect process– combined, including the stages of waste compaction, pyrolysis and high-temperature gasification (to produce synthesis gas, inert and some mineral products and metals);
Siemens process - pyrolysis– combustion of pyrogas and separated carbonaceous residue using non-oxygen-enriched blast.

Combustion of solid waste in boiler furnaces (KR process) due to relatively low temperatures (600 – 900 °C) practically does not solve the dioxin problem. In addition, this creates secondary (solid, unburned) slags and dust, which require separate processing or are sent for disposal with subsequent negative consequences for the environment. These shortcomings are to a certain extent inherent in the QE process. Here we add the need to prepare raw materials for processing in order to maintain the particle size distribution.

The disadvantages of the process developed by the Institute of Chemical Physics of the Russian Academy of Sciences include:

the need to sort and crush waste to certain sizes; addition and subsequent separation of coolant of a given granulometric composition;
the need to develop an expensive flue gas purification system - synthesis gas, which is a mixture of carbon monoxide and hydrogen.

Biothermal processing of solid waste: Aerobic fermentation

Of the biothermal methods in practice, the most widely used is aerobic fermentation, which is often called composting (after the name of the final fermentation product - compost, used in agriculture).

According to the results of research by English specialists, at the initial stage of fermentation, mineralization of the mixture occurs, as evidenced by a decrease in the total carbon content of organic matter and humic acids. The resulting biomass has a high degree of polymerization and is characterized by a significant (compared to soil) nitrogen concentration. During the fermentation process, the content of phenolic groups in the biomass decreases and the content of HOOC and C=0 groups increases.

As a result of the completed fermentation process, the mass of biodegradable material is halved and a solid, stabilized product is obtained.

Composting of solid waste developed most intensively from the late 60s to the early 80s, mainly in Western European countries (Italy, France, the Netherlands). In Germany, the peak of plant construction occurred in the second half of the 80s (in 1985, 3% of solid waste was processed into compost, in 1988 - about 5%). Interest in composting increased again in the mid-90s based on the involvement in processing not of solid waste, but of selectively collected food and plant waste, as well as waste from gardening and park complexes (thermal processing of this waste is difficult due to high humidity, and burial is associated with uncontrolled formation of filtrate and biogas). In European practice, by 2000, about 4.5 million tons of waste were processed annually using aerobic fermentation at more than 100 plants (of which 60 plants were built in 1992-95).

In the CIS countries, direct composting of original solid waste is used at nine plants: in St. Petersburg (the first plant in the former USSR, built in 1971; at the end of 1994, the second plant was commissioned in St. Petersburg), Nizhny Novgorod, Minsk and Mogilev, Tashkent, Alma-Ata, Tbilisi and Baku (all plants were designed by the Giprokommunstroy Institute, Mogilevsky - by the Belkommunproekt Institute). In 1998, a plant was put into operation in Tolyatti, where preliminary, but ineffective sorting of solid waste was implemented.

In the first mechanized industrial plants, solid waste was most often composted in piles, periodically subjecting the material to tedding.

Currently, three methods of aerobic fermentation are most common in industry:

fermentation (composting) in biodrums;
tunnel composting (fermentation);
fermentation (composting) in a holding pool.

Proper waste disposal is a huge step towards improving the environment.

There is more than one way to recycle waste.

The main task of each method is to complete the task without allowing the spread harmful bacteria and microorganisms. At the same time, it is necessary to minimize the harmful substances released during disposal itself.

Let's look at waste disposal options and evaluate how effective each of them is.

Disposal of waste at landfills

Landfills serve to collect and process waste naturally. Many of them use a very simple and understandable recycling system: as soon as a certain amount of garbage is collected, it is buried. Not only is this method outdated, it is a time bomb, because there are materials that do not decompose for decades.

Those few testing sites that have production workshops at their disposal operate as follows: arriving cars are registered at the checkpoint. The volume of the body is also measured there to determine the cost of disposal; radiation levels are measured. If it exceeds acceptable standards, the car is not allowed through.

From the checkpoint, the car is sent to the waste sorting workshop. Sorting occurs manually: a machine feeds garbage onto a conveyor belt, and workers from there select bottles, paper, etc. The sorted materials are placed in containers without a bottom, from which the garbage goes directly into the cage and under the press. When the process is completed, the remaining waste (not included in any of the categories) is also compacted and taken directly to the landfill. Since long-decomposing materials have been sorted, the remaining waste can be covered with soil.

Plastic bottles, cardboard and some other waste are purchased by enterprises for production. For example, from plastic bottles and containers, nets for vegetables are made from glass bottles and fragments - new products, made of cardboard - toilet paper.

Materials accepted at landfills:

Household waste from residential buildings, institutions, enterprises engaged in the trade of industrial and food products.
Waste construction organizations, which can be equated to municipal solid waste.
May be accepted industrial waste 4 hazard classes, if their quantity does not exceed a third of the accepted waste.

Waste, the import of which is prohibited to the landfill:

Construction waste 4 hazard classes, which contains asbestos, ash, slag.
Industrial waste 1, 2, 3 hazard classes.
Radioactive waste.
Landfills are arranged according to strict sanitary standards and only in those areas where the risk of human infection by bacteria through air or water is minimized. The occupied space is designed to last approximately 20 years.

Composting

This processing method is familiar to gardeners who use rotted organic materials to fertilize plants. Waste composting is a disposal method based on the natural decomposition of organic materials.

Today there is a known method for composting even an unsorted stream of household waste.

It is quite possible to obtain compost from garbage, which could later be used in agriculture. Many factories were built in the USSR, but they stopped functioning due to the large amount of heavy metals in the garbage.

Today, composting technologies in Russia come down to the fermentation of unsorted waste in bioreactors.

The resulting product cannot be used in agriculture, so it is used right there in landfills - it is used to cover waste.

This disposal method is considered effective provided that the plant is equipped with high-tech equipment. Metals, batteries, and plastic are first removed from the waste.

Advantages of waste incineration:

less unpleasant odors;
the number of harmful bacteria and emissions is reduced;
the resulting mass does not attract rodents and birds;
It is possible to obtain energy (thermal and electrical) during combustion.

Flaws:

expensive construction and operation of waste incineration plants;
construction takes at least 5 years;
When burning waste, harmful substances are released into the atmosphere;
Incineration ash is toxic and cannot be stored in conventional landfills. This requires special storage facilities.

Due to a lack of city budgets, inconsistency with waste processing companies and other reasons, the production of waste incineration plants has not yet been established in Russia.

Pyrolysis, its types and advantages

Pyrolysis is the burning of waste in special chambers that prevent the access of oxygen.. There are two types:

High temperature - the combustion temperature in the furnace is over 900°C.
Low temperature - from 450 to 900°C.

When comparing conventional combustion as a method of waste disposal and low-temperature pyrolysis, the following advantages of the second method can be identified:

obtaining pyrolysis oils, which are subsequently used in the production of plastics;
release of pyrolysis gas, which is obtained in sufficient quantities to ensure the production of energy resources;
stands out minimum quantity harmful substances;
Pyrolysis plants process almost all types of household waste, but the waste must first be sorted.

High-temperature pyrolysis, in turn, has advantages over low-temperature pyrolysis:

no need to sort waste;
the mass of ash residue is much less, and it can be used for industrial and construction purposes;
at combustion temperatures above 900°C they decompose hazardous substances without getting into the environment;
The resulting pyrolysis oils do not require purification, since they have a sufficient degree of purity.

Each waste recycling method has advantages, but it all depends on the cost of installations: the more efficient and profitable the recycling method, the more expensive its installation and the longer the payback period. Despite these shortcomings, the state is striving to implement projects for efficient and safe waste recycling, realizing that these technologies are the future.