A study was made of the adsorption of chloroform from aqueous solutions on activated carbon (AC) of Ag-3, AG-OB-1, SKD-515 grades. The sorption process in kinetic and dynamic conditions is studied, the mechanism of mass transfer during the adsorption of chloroform to AC of different grades is shown. A method is proposed for optimizing the parameters and modes of the continuous adsorption purification process, based on the fundamental equation of the external diffusion dynamics of adsorption. The main parameters of the adsorption dynamics are determined: the length of the working layer, the length of the unused layer, the coefficient of protective action. On the basis of a complex study of the process of adsorption (equilibrium, kinetics and dynamics) of chloroform, optimization of the purification regime and parameters of the adsorption column using mathematical modeling, an effective technology of additional water purification from the system of centralized domestic drinking water used in the production of fruit and whey drinks was developed.

The potential of the ore-bearing territory and the dumps of the former mine placed on it are estimated from the point of view of application of new technological solutions that will allow to process the man-made rock mass profitably. The nature of the distribution of gold by size classes is established, which can significantly reduce the volume of processed rock mass. Theoretical substantiation of acceleration of natural segregation with application of low-frequency sound influence is given. The segregation-diffusion concentration of gold is proposed, which allows in the future to create an energy-efficient technology of recovery from man-made waste and apply it to the processing of gold deposits still in the depths.

Field and laboratory studies of the composition and properties of solid municipal waste have been performed, on the basis of which the quantity and quality of the recovered secondary raw materials and "tailings" of sorting, which are used as energy fraction or solid fuel from waste, are simulated. The elemental composition for dry ashless (combustible) mass for all considered variants of solid fuelcomposition from wastes is calculated. Presented is the ratio C: O and heat of combustion on a dry basis for different versions of solid fuel composition from waste. For comparison, the C: O ratio is shown for various components of solid fuel from waste: for synthetic materials (polymers, rubber) and for biodegradable materials (organic waste, waste paper, wood).

The formation of cellular silicate glasses from sulfide-alkaline solutions and amorphous silicon oxide has been studied. The mechanism of formation of silicates from sodium hydroxide and amorphous silicon oxide and processes of gasification with the participation of the organic component of waste are considered. Technological solutions for recovery of sulfide-alkaline solutions are proposed. At the same time, the process of recovery consists in mixing sulfuralkaline waste with natural amorphous silicon oxide, tripoli, and further roasting the resulting composition at glass formation temperatures. As a result of heat treatment, sulfur from organosulfur compounds is oxidized to sulfur (IV), and sodium hydroxide, after dehydration, enters in composition of the resulting vitreous silicate cellular material.

The possibility of applying the thermal method for neutralizing waste re-insulation during the major overhaul of main gas pipelines is considered. The initial composition of the organic part of the waste is shown. The thermal effects observed during the decomposition of waste in a controlled atmosphere, the composition of waste gases and the results of thermal analysis of waste samples resulting from the replacement of insulation of gas pipelines selected for maintenance and repair of linear sections of main gas pipelines are examined. Ways of solving the problem of elimination of waste generated during the gas pipeline overhaul are suggested.

The results of experimental studies on the effect of metal-cutting oils (MCO) on potting soil microbiocenosis are presented. Comparative characteristics of microbiocenosis of contaminated soils with microbiocenosis of urban soils and sod-podzolic soils were carried out. The effect of various concentrations of coolant on soil enzymes (dehydrogenase, catalase, urease) is shown, and the dependence of urease activity of soils on the concentration of coolant is revealed, and therefore, the parameter "activity of urease" is recommended as an indicator in assessing the level of soil contamination of the coolant.

The actual problem of searching for effective ways of handling municipal sewage sludge has been studied on the basis of the principles of circular economy. In this context, the shortcomings and advantages of the following methods for handling sewage sludge are analyzed: placement on mud maps and MSW landfills, gasification, pyrolysis and incineration; a conclusion was made about the prospects of incinerating sewage sludge. The methods of additional sewage sludge pretreatment or post-processing of incineration products are considered, which allow to minimize the main disadvantages of this method of sewage sludge utilization - the loss of basic nutrients, a large volume of toxic secondary waste, and a high consumption of primary energy resources. An improved method for handling sewage sludge based on the incineration method is proposed with the introduction of additional stages of preparation for incineration, including complex dehydration, detoxification of sewage sludge and the formation of a fuel mixture.

A method for remediation of contaminated soils is presented, which includes a complex of mechanical, chemical and biological measures. At the initial stages, it is proposed to conduct gypsum and wash with fresh water. A special feature of the biological stage is the use of a vegetable sorption material based on sawdust of hardwood trees with immobilized on their surface biomass of aboriginal oil-oxidizing halophilic microorganisms. A special nutrient medium for microorganisms has been selected. For the final stage — phytorecultivation — selected plantshalophytes. The developed method of remediation of oil-saline soils allows to reduce the content of pollutants (oil and oil products, chloride ions) to an environmentally safe level.

Studies have been carried out to improve the quality of conversion calcium carbonate. The process of extraction of insoluble iron-containing impurities at the stage of obtaining calcium carbonate from calcium nitrate melt was studied. It has been determined that the preliminary removal of the acid-insoluble residue from the melt of Ca (NO₃)₂ by filtration or settling allows the Fe₂O₃ content to be reduced by more than 50 % in the form of magnetically susceptible impurities and further increases the whiteness of the final product. The effect of grinding and heat treatment of conversion calcium carbonate on the evolution of nitrogen-containing impurities is studied. It has been established that the amount of water-soluble substances in the sample increases exponentially with increasing shredding time of the material. Heat treatment can significantly reduce (in almost 3 times) the total content of water-soluble substances in the crushed product. Simultaneously with the removal of the "bound" nitrogen, the content of the main component increases by 1.5–2 %. A positive effect of heat treatment is also an increase in the rate of refinement of conversion calcium carbonate, which makes the dispersed composition of the product more homogeneous. A technological scheme for processing conversion calcium carbonate into a disperse filler with specified properties has been developed.

The results of the studies of reducing the toxicity of vehicle exhaust gases of car diesel by conversion to alcohol-fuel emulsions are presented. At the same time, the necessity of applying alcohol-fuel emulsions as an environmentally friendly fuel is grounded. In order to develop, determine and optimize the composition of alcohol-fuel emulsions, their tests were carried out when the diesel engine is operated with diesel fuel, methanol and ethanol-fuel emulsions. Experimental studies have established that in car diesel engine 4 Ч 11,0/12,5, emulsions with the following composition may be optimal for use, %: alcohol (methanol or ethanol) – 25, detergent-dispersant additive succinimides C-5A -0.5, water – 7, diesel fuel – 67.5. Conversion of car diesel from diesel oil to methanol-fuel emulsion reduces the content of carbon black (C) in exhaust gases by 6.9 times, nitrogen oxides (NOx) by 41.3 %, carbon dioxide (CO2) by 6.7 %, oxide carbon (CO) by 45.0 %; on the ethanol-fuel emulsion – C in 5.2 times, NOx by 50.2 %, CO2 by 23.8 %, CO by 25.0 %.

Based on the analysis of the current situation with gas supply in the region (low gas supply of the population, lack of thermal generation based on gas), possible ways of solving the problem of providing gas for housing, industrial and communal facilities in the Republic of Tuva are being considered. The results of a study of the possibilities of using liquefied hydrocarbon gas, gas extracted from coal mining in the Ulug-Khem basin, gas from the underground fire of the Erbeksky coal deposit are presented. The needs for gas of all categories of consumers are estimated: the population, thermal generation enterprises, social and household spheres in the region. Prospects for gas supply are set out in connection with the solution of environmental problems: the reduction of air pollution in cities and towns. The directions of the solution of the problem of gasification of Tuva in the long-term prospect are substantiated, options for transferring the economy of the republic to the main gas supply, construction of the oil product pipeline are considered.

At present, various ways of improving the territories are widely used, including methods of technical soil reclamation, and in particular injection methods. In this regard, the toxicity analysis of the most frequently used injectable materials is extremely important for a wide range of specialists, both for builders and designers, and for scientists developing new methods. The comparative characteristic of toxicity of components of injectable solutions is given, conclusions and recommendations of use for barrier technologies are the safest from the ecological point of view of materials.