CC BY
25UDC 504.064.45
Karelin A.E.
Graduate student Petrosov S.P.
Doctor of Technical Sciences, Professor Alekhin S.N.
Candidate of Technical Sciences, Associate Professor
Dmitrienko N.A.
Candidate of Pedagogical Sciences, Associate Professor Institute of Service and Entrepreneurship (branch) of the DSTU in Shakhty
DOI: 10.24411/2520-6990-2019-10802 PROSPECTS FOR THE DEVELOPMENT OF AUTOMATIC SORTING SYSTEMS FOR MUNICIPAL
SOLID WASTE IN THE RUSSIAN FEDERATION
Abstract
This article discusses the general waste management system in Russia, which includes five main areas (landfills, waste sorting complexes, waste incineration complexes, waste recycling complexes, MSW composting plants). The practical usage of various utilization types of municipal solid waste in developed countries was analyzed. Comparative characteristics of manual and automatic method of MSW sorting are in the article.
Key words: waste processing, municipal solid waste, waste sorting, secondary raw materials, manual waste sorting, automatic waste sorting.
Introduction. According to Rosprirodnadzor [1], about 35-40 million tons of municipal solid waste (MSW) is generated annually in Russia, and the number increases every year.
Today, the following methods for MSW utilizing are landfill, bio thermal composting, mechanical and biological treatment, incineration and pyrolysis [2].
The main method of MSW disposal in Russia is landfill, because of which the waste decomposes and serves as a source of environmental pollution with toxic elements and compounds. Thus, the need for recycling is of paramount importance. This is important not only from the environmental point of view (reducing the amount of waste that is disposed of at landfills, reducing the area of degraded land, reducing the load on the environment), but also from an economic point of view.
Household waste contains up to 50-60% of secondary raw materials [3], realizing how much you can get as a stable income, since the flow of solid waste does not run out.
It should be borne in mind that the preliminary sorting of garbage has not yet become widespread in Russia.
The structure of the waste management system.
The general waste management system in Russia includes five main links (Figure 1):
- landfills,
- waste sorting complexes,
- waste incineration complexes,
- waste recycling complexes,
- plants for MSW composting.
Figure 1 - General waste management system
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The strategy for the removal of MSW to landfills provides for their destruction by landfill with the subsequent receipt of biogas produced in the process of decay of garbage. The waste processing strategy provides in most cases a sequence of operations for the collection, sorting and final processing of MSW into secondary raw materials. Composting is a biochemical process of decomposition of the organic part of MSW by microorganisms. As a result of the interaction of organic substances, oxygen and bacteria, carbon dioxide, water and heat are released. The composting product is organic fertilizer - compost or biofuel (raw compost).
Currently, there are several technologies for MSW processing in Russia. In fact, the choice of optimal strategies is based on the environmental, resource and
economic requirements of the region. The best way to smooth out the shortcomings of each individual method is to build industrial technology by means of combining various processing methods.
Solid waste is generated as a result of human activities. They are capable of generating pollution and other hazards to the global environment. In addition, most solid waste can be used as secondary raw materials, such as metals, plastics, glass, paper, old tires, etc. When processing waste, we save lot of energy, resources and raw materials, which will lead to a significant improvement in the environment and climate [4].
World practice of using various types of MSW disposal is given in table 1.
Table-1
Percentage of MSW disposal methods in developed countries
Country Disposal method
Combustion burning , t Landfills, t Composting, t Other, t
USA 17 81 - 2
Great Britain 7 92 1 -
France 37 53 10 -
Germany 21 73 6 -
Austria 73 19 7 1
Italy 13 84 3 -
Russia 6 94 - -
Japan 70 17 1 12
South Korea 18 79 2 1
Solid waste is collected and fed to the treatment plant in the form of a mixture of various solid materials. In order to separately process the various ingredients in the waste mixture and to reuse it, the mixture is crushed, classified and sorted in the waste treatment
plants. Among these processes, sorting is the determining stage in which materials with the same recirculation characteristics are concentrated and cleaned of impurities [5]. When sorting waste, various streams of materials of secondary resources are formed (Figure 2).
Figure 2 - Scheme of flows generated during sorting of MSW
Currently, there are three types of MSW sorting: manual, automated and automatic.
In manual sorting, materials are recognized by personnel visually and manually selected. As a rule, screening class material of +200 mm, sometimes +300 mm, is subjected to manual sorting. The productivity of one sorting line depends on the composition of enriched
raw material and ranges from 3 t / h [6]. The effectiveness of manual sorting largely depends on the organization of work at the stage of waste collection and transportation.
In automated sorting, certain auxiliary operations (feeding material to the sorting conveyor, preliminary
screening by size, grinding) are mechanized, but recognition is carried out by a person.
Automatic sorting is a modern stage in the field of MSW management. On lines of fully automatic sorting of materials, the entire process of sorting waste (identification of selected materials and their allocation from the general flow) occurs without the participation of a staff. As a rule, the technology of automatic sorting is
based on the use of sensors for the optical determination of materials by irradiating the waste stream with radiation with a certain wavelength and subsequent spectral analysis of the radiation reflected from the surface of the material [7]. Recently, the method of automatic sorting of MSW based on the use of neural networks has been actively developed abroad.
Table 2 shows the comparative characteristics of the manual and automatic sorting method.
Table-2
Advantages and disadvantages of the manual and automatic sorting method
Sort type Advantages Disadvantages
Manual - simplicity of equipment; - purity of selected components - high safety requirements; - incomplete extraction of various fractions of MSW; - the difficulty of identifying the material based on visual inspection; - low selection rate, which makes the process of processing large volumes of MSW practically unfeasible
Automatic - purity of the selected components; - high speed sorting; - the ability to sort by several parameters - high cost of equipment; - the appearance of new materials missing from the system database
Conclusion. Foreign and domestic experience in the processing of municipal solid waste shows that at present there is practically no single universal method or scheme for MSW sorting, which simultaneously meets all economic, technological and environmental requirements. Each of these sorting methods has some advantages and disadvantages. Thus, the use of an intellectual component in the MSW sorting system can allow increasing the efficiency of MSW processing of technological process.
References
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