RUDN Journal of Ecology and Life Safety

Post-consumer plastic containers and packaging, even sorted by types of the main polymer, are very heterogeneous, because they contain other materials and substances - packaging elements, internal and external contaminants. The share of target material in waste and secondary resource flows is important for assessing the recycling prospects - the higher the content of secondary materials, the lower the output of recycled materials will be. The paper presents the results of experimental studies to determine the composition of plastic waste. In the polyethylene and polypropylene waste different components were identified, namely, target plastic (the “body” of the package), lids/dispensers, labels/stickers and contaminants (liquids, dirt, food, etc.).

The relevance of the problem of regeneration, recycling and reuse of waste technical oils is due to modern trends in technological development, tightening of legal regulation in the field of industrial waste management, as well as the need to implement the principles of resource conservation and sustainable nature management. The aim of the study is to develop and justify an integrated technological approach to the regeneration of waste oils, aimed at restoring the performance characteristics of products while ensuring environmental safety and economic feasibility. The object of the study is waste technical oils, modern processing methods, as well as the range of commercial lubricants obtained on their basis, taking into account the areas of their industrial application. The methodology is based on a systems approach that combines environmental, economic and technological aspects. The paper considers the features of the composition and properties of waste technical oils, the transformation of their physicochemical characteristics under the influence of exogenous and endogenous factors. Potential risks of hydroecological pollution, soil and environmental disturbances and anthropogenic impact on the human body in case of violation of disposal rules are identified. The study analyzes waste oil regeneration methodologies based on fundamental and modern approaches. Membrane technologies are highlighted, which represent an innovative cleaning method using highly selective filter elements that allow deep refining of oil at the molecular level. The article describes the production of commercial lubricants from waste oils, the processing stages, and the sequence of process operations. The environmental and economic benefits of recycling are determined, and the problems and prospects for the development of the industry are identified. The integrated approach covers the integrating principles of environmental safety and economic feasibility. The results of the analysis confirm that the regeneration of waste oils into lubricants is a sustainable solution that contributes to the formation of a closed resource management cycle.

The study analyzes the most important areas of processing acid tars, a specific type of non-permanent composition waste, the main source of which are the processes of oil refining and storage. Among the complex of substances included in the composition of acid tars are very aggressive components of high hazard classes, which creates risks of secondary pollution of natural environments when the storage tank is overflowing or loses its integrity. Despite more than 100 years of development history, sufficiently effective technologies for their processing have not been proposed to date. For Russia, the problem is very relevant: several storage facilities for this type of waste are included in the register of objects of accumulated environmental damage and are subject to prompt environmental rehabilitation. As a solution to the problem, it is proposed to apply an approach consistent with the principles of green economy: neutralization of acid tars using waste from other industries, such as the food industry or agriculture. The result of neutralization is a decrease in the degree of hazard of waste for the environment, “mutual neutralization” of waste of various origins and the prospect of obtaining material suitable for economic use. In addition to the actual technological solution for waste neutralization, it is proposed to systematize information on existing technologies in this area - to create an information and reference system. Which will allow organizing information on developments and will facilitate the selection of optimal solutions for each storage facility, taking into account the individual characteristics of the stored waste and the availability of technological solutions from the standpoint of the best available technologies (economic, environmental, technological availability and efficiency).

Electronic waste poses a serious environmental threat due to the content of heavy metals. The aim of the work is to evaluate the leaching of heavy metals (Cu, Pb, Zn, Cd, Cr, Ni) from printed circuit boards and cables under simulated urban landfill conditions (SPLP method, 8 cycles). E-waste was found to be a significant source of contamination. Printed circuit boards showed a gradual increase in the concentrations of Cu (up to 2.33 mg/L), Pb (up to 0.666 mg/L) and Zn (up to 1.385 mg/L) in the leachate. The cables were characterized by high initial Cu removal (3.50 mg/L) followed by a decrease. A heuristic risk assessment model was developed.

The design and construction of thermal waste disposal facilities (including energy production) faces a number of limitations when choosing the technologies used. One of the most important environmental requirements is to prevent the release of toxic compounds contained in the combustion products of household waste, including carcinogenic substances. One of the groups of these compounds is polycyclic aromatic hydrocarbons (PAHs): toxic hydrocarbon compounds that are persistent in the environment, which are present in the combustion products of many materials and may also be petrogenic in nature (they are formed during low-temperature processes not related to burning). An important property of PAHs is marker qualities: their presence in the studied objects indicates a certain source of their origin (linked to certain natural or man-made processes). PAH concentration ratios are used in many domestic and foreign studies to identify the source of contamination. However, the boundary values of the indicator ratios used do not always fully unambiguously characterize the source of pollution, and the ratios themselves are informative to varying degrees for different environments and different natural conditions. The purpose of the article is to substantiate the use of PAH indicator ratios for pollution control as a result of incineration of various categories of waste. The materials for the study are the results of analytical determinations of polyarene concentrations in waste incineration products at domestic and foreign thermal recycling facilities. Indicator ratios of PAHs (a method of “environmental fingerprinting” of pollution sources widely known in foreign practice) have been tested for these objects. Using the methods of multidimensional data analysis (the principal component method), the most informative indicator ratios that can be recommended for use have been determined. Identification of the genesis of PAHs makes it possible to control the amount of pollution in the components of natural environments caused by emissions and waste from the combustion of materials, which contributes to a more objective control of anthropogenic loads.

The research is devoted to the analysis of a comprehensive approach to the organization of a student workshop that combines practical recycling of plastic waste, environmental education, and the formation of professional competencies. The relevance of creating such centers on the basis of universities in the context of solving the tasks of the national project “Ecology” and the goals of sustainable development is substantiated. An analysis of technological solutions for small-scale recycling has been conducted, which shows the feasibility of using open solutions (Precious Plastic) for educational purposes. The author’s workshop model, implemented at the Ufa University of Science and Technology, has been described in detail. It includes the stages of collecting (specialized art object), shredding (bicycle shredder), and thermal processing (injector, thermal press) of plastic caps. Practical recommendations for replicating the practice are provided.

The use of microalgae grown during the utilization of CO2 from flue gases as organic fertilizers opens up new perspectives for simultaneously solving two of the most significant problems of our time - decarbonizing production processes (by reducing CO2 emissions from fuel combustion) and enhancing the agricultural sector’s productivity (through increasing crop yields). Given the availability of developed technologies for the disposal of CO2 from flue gases, which are a continuous source of microscopic algae growth, it is important to explore the possibility of using the resulting biomass for use as fertilizer. Two types of biofertilizers based on two cultures of microalgae Chlorella sp. grown in the presence of flue gas were studied. The first culture was obtained from the biological agents «Spirulinafood». The second culture was a consortium of green microalgae of various species, with a predominance of Chlorella sp. It was isolated from a freshwater pond. A study of the effectiveness of biofertilizers has shown an increase in the length and weight of aboveground rapeseed seedlings. The optimal application conditions include dilution of the solutions with a biomass content of 2.4-2.8 g/dm3 and an optical density of 1.3-1.5, in a ratio of 1:9. This provides an increase in seedling length by 13% and weight by 13% The use of biofertilizer from a pure culture of Chlorella sp. (the biological agents «Spirulinafood») allowed to increase seed germination energy by 6% and the percentage of seed germination, and an elemental analysis revealed an increase in the content of magnesium and phosphorus in the composition of the fertilizer. The results obtained confirm the prospects for further research and the inclusion of biofertilizers from microalgae cultivated in flue gas conditions in modern agrotechnological processes