An effective method and device for additional heating of fuel oil used in the production of soda ash as fuel in soda drum dryers has been developed. It is concluded that the use of a high-frequency induction unit mounted on the fuel oil supply line in the thermal power equipment of soda ash drum dryers provides an increase in the temperature of fuel oil from 60 to 98 °С, a reduction in its specific consumption by 15.7 % and a reduction in carbon monoxide emissions into the atmosphere from 0.20 to 0.024 g /s.

Pilot plants were developed to analyze heat and mass exchanges during the thermal decomposition of ligninocellulose. Methods of experimental research to determine the properties of thermal decomposition products were presented. Studies of thermal decomposition of plant raw materials for classical and high-temperature modes of slow pyrolysis were carried out. The pore structure of the obtained carbonate samples was studied. Optimal modes of slow conductive pyrolysis of vegetable raw materials were proposed. The paper presents the variant of industrial pyrolysis of plant waste into activated carbon.

The description of the developed infrared on-board differential absorption lidar for measuring methane content in the air was presented. The lidar was installed on board of aircraft-laboratory Tu-134 "Optic". Flight tests of the developed lidar and experimental measurements of methane concentration along the vertical routing were carried out in the summer atmosphere of mid-latitudes. Lidar measurements of methane content in the air were analyzed. They were compared with local measurements from the gas analyser installed on board of aircraftlaboratory and the results of preliminary numerical modelling. It was concluded that the on-board lidar can measure methane concentration within background values in the mid-latitude summer atmosphere.

Pre-processing of ash from coal power plants were carried out, which consists of its decarbonization and iron removal to produce a carbon concentrate with a carbon content of 71 % for reuse in the power sector and magnetite concentrate from flotation tailings as an additional raw material in ferrous metallurgy. The optimal consumption of flotation reagents and flotation duration were identified. To increase the concentration of iron intended for magnetic separation, desliming of flotation tailings was recommended.

The advantage of electrical separation in the processing of classified ash and slag as the main separation operation was substantiated. It was recommended to switch to electrical separation as the first technological operation and carry out the entire cycle of ash and slag processing using dry methods due to their economic benefits compared to wet ones. It was emphasized that dry methods do not require the reagents and do not lead to subsequent secondary pollution of the environment. The possibility of obtaining iron-containing and aluminosilicate products for construction and other industries was confirmed.

It was shown that water-diluted spray after hyperbaric welding area demonstrates pronounced bacteriological inhibition. It was found that water after hyperbaric welding, in addition to growth inhibition, also induces the synthesis of natural inhibitors of living organisms – biocins, which adversely affect the ecosystem. It was concluded that such properties are useful in the economy, in particular, for initiating an increased synthesis of biocines in bioreactors for the purpose of further isolation and inclusion in technologies as natural growth inhibitors.

The paper presents the application results of geophysical methods (micro-near-field time-domain electromagnetic sounding and ground penetrating radar profiling) performed in 2022 to determine the volume of homogeneous industrial waste in collection ponds using the example of the phenol lake within the city limits of Ulan-Ude , The Republic of Buryatia. The boundaries and volumes of industrial waste disposal were determined, and the position of the overlying and bottom beds of the phenol pound were recorded. The migration channel of hydrophilic chemical pollutants from the bed of the studied object was identified and the reservoir was installed to collect, over the years of infiltration processes, fluid saturated with hydrophilic chemical pollutants from the phenol pound. 3D models of the industrial waste deposits in the phenol lake and 3D models of the identified collector were built. It was concluded that the used set of geophysical methods was effective for solving similar engineering, environmental and geoecological problems.

The peculiarities of fuel consumption in Russian regions were revealed — the energy sector consumes 40 % of the country's fuel resources, but its role is declining. There was an increase in fuel consumption by industries and population. The fuel balance of the regions revealed a predominance of gas in the European part and coal in the eastern regions with an increase in the share of associated gas. Thanks to the modernization of the power industry in most regions of Russia, emissions from fuel combustion have decreased and industrial production has increased.

The content of the main ore and associated elements in the material of the tailings of the Altai mining and processing plant, in the snow cover and surface waters of the dumps, as well as in the water filtrates of the dump material was studied. It was detected that the concentration of Cu in the substrates of the dumps of the Altai mining and processing plant varies from 970 to 7350 mg/kg and exceeds the background values of the copper content in the soils of Northwestern Altai up to 1000 times, the Pb content varies. from 850 to 2800 mg/kg and exceeds the background value up to 500 times, Zn – up to 200 times (content from 350 to 12170 mg/kg), Cd – up to 100 times. It was recorded that the Pb content in pound surface water on of tailings dumps exceeds the MPC of hazardous substances 2.5 times and is 79 μg/l, Cu – 52 times (52.3 mg/l), Zn – 250 times (254 mg/l), Cd – 940 times (0.94 mg/l). It was identified that in liquid media – lysimetric, surface and snow waters of the Altai mining and processing plant tailings pond – the ratio of pollutant concentrations to background and standards norms (Russian and foreign) is higher for more labile and easily leachable elements – cadmium and zinc. In solid components (substrates, snow dust), the concentrations of copper and lead noticeably exceed the background, clarke and standard concentrations.

The results of monitoring the dynamics of the release of pollutants into the environment with meltwater from the snow landfill were presented. The concentrations of pollutants in water at the beginning and end of the active melting period were identified. The concentrations of pollutants were found to exceed background values for heavy metals. The concentrations of pollutants in meltwater at the beginning and end of the period of active melting were analyzed. At the end of the period, a decrease in the concentration of most pollutants was detected, with the exception of some of them, such as Fe, the concentration of which was 17 times higher, which is associated with the high iron content in the waste layer of the landfill. A significant increase in the concentration of pollutants was detected at the site of sedimentation of sludge in the swamp ditch.

The possibility of using a parametric tolerance interval to improve the accuracy of studying water quality indicators was analyzed. It was demonstrated that the proposed approach provides advantages over non-parametric interval rank, but not in all cases. The advantages of the new method due to the use of more complete experimental information were substantiated, and the reasons for the decrease in the accuracy of water quality assessment at its application were analysed.