The efficiency of integrated gas emissions treatment in thermal waste treatment units from dust particles and fossil sour traces of SO2, HCl and HF, as well as volatile organic compounds (VOCs) and dioxins at 300–400 °C of the gas mixture with a ceramic gas filter with aluminosilicate fibers added with catalytic MgCr2O4. The efficiency of sorption purification of tail gases from SO2, HCl and HF during the test period was 79–90 %, which depended on the supply of slaked lime to the catalytic filter to prevent catalyst deactivation. Thermal mode of chemical refining (300–400 °C) provided effective catalytic purification from VOCs, CO, and dioxins in combination with the chemisorption recapture of catalytic poisons and dust, preventing neither sorbent degradation nor damage to the catalyst.

The paper provides an overview of existing methods and sorbents for the elimination of hydrocarbons from the surface of the water, studied their characteristics and the principle of operation of devices that are currently used to eliminate oil spills. An original method of eliminating hydrocarbon spills is proposed, the main element of which is the creation of a controlled vortex funnel in a rotating cylindrical cup equipped with a suction system for petroleum products. The principle of operation and methods of controlling the modes of operation of the vortex funnel have been confirmed by experimental studies.

The results of studies on wastewater treatment from lignosulfonates by the method of induced reagent flotation were presented. The factors influencing the purification efficiency and technological regimes were identified, as well as the choice of activated carbon grades for deep post-treatment of wastewater were substantiated. Based on the research, a method was developed for treating local wastewater from lignosulfonateswith a flotation filter.

The study concerned the of obtaining stone-cast products from unmodified blast-furnace slag from Severstal PJSC and its mixture with river sand as a source of silicon dioxide. Mechanical characteristics, surface morphology, cutting microstructure and phase composition of products resulted from blast furnace slag and sand were studied. It was shown that when casting synthetic stone in an electric arc furnace without using a controlled cooling mode, it was possible to obtain a slag casting, the structure of which from chain silicates has a density of 2.9–3.0 g/cm3 and a compressive strength of 44.0–71.4 MPa.

Surface layers of apatite-nepheline ores mill tailings were analyzed. During the snowless period in

2022, the dynamics of PM2.5 and PM10 dust concentrations in the atmosphere air of Apatity, Murmansk Region, was studied. Excess of MAC of sparingly solubles were detected. Mineralogical analysis of tailings and dust samples were carried out, the presence of nepheline and sodalite was detected, which confirms the involvement of tailing dumps of apatite-nepheline processing plants in air pollution. It was concluded that, in addition to the tailing dump, transport and other industrial sites have a significant impact on the atmosphere air, since airborne dust samples contain small particles of oxidized iron, plastic, glass, and metal scale. The role of green areas in buffer zones and within the boundaries of urban development was emphasized.

It was shown that the use of methods of chemical analysis of oil-contaminated soils recommended for environmental control, showed no more than 50% of the mass of oil introduced into the soil, even in freshly contaminated samples. It was found that main errors were associated with the loss of light oil fractions during drainage of contaminated soil samples, incomplete extraction of pollutant oil from soils, ignoring high-molecular polar oil fractions, resinous and asphaltenic fractions when using these methods. A slight modification of the applied preparatory analytical methods was proposed, wich consisted in replacing the cold extraction of contaminated soil with a hot one, followed by additional weighing of the extracted chloroform prior swing absorption to assess the content of oil products, as well as soil samples for extraction at a natural moisture level without air- dry preconditionning. It was concluded that these changes significantly reduce analytical errors and increase the reliability of monitoring soil pollution during crude oil spills, as well as the effectiveness of rehabilitation actions.

The results of monitoring the biological properties of indigenous bacterial strains isolated from soils, which for a long time were in contact with highly concentrated wastewater from the slaughterhouse of meat processing units, were presented. The resulting strains are able to grow on slaughterhouse wastewater in the presence of animal fats as a carbon source in concentration exceeding the maximum acceptable level for wastewater intended for biological treatment with activated sludge, it demonstrated combined high growth rates and resistance to chlorides. The stimulating effect of wastewater treated by combined indigenous bacterial strains on the germination of barley and corn seeds was confirmed. These strains were identified as Stenotrophomonas rhizophila.

Regional maximum permissible concentrations of gross lead in soils were determined in the area of the non-ferrous metallurgy enterprise – the largest Electrozink plant in Russia, located in Vladikavkaz (Republic of North Ossetia-Alania) and a source of environmental pollution with lead, zinc and cadmium. Modeling of lead contamination of five types and subtypes of soils most closely lying to the metallurgical enterprise was carried out. The following of gross lead concentrations were established in soils in the area of the metallurgical enterprise: chernozem leached – 160 mg/kg, chernozem ordinary – 150 mg/kg, dark gray forest – 120 mg/kg, mountain-meadow soddy – 110 mg/kg, brown forest weakly unsaturated – 100 mg/kg.

The state of soils and vegetation in the valleys of the Tolych and Zyryanka rivers (Promkanal, Berezniki) was assessed and changes due to discharges from large industrial facilities were identified. In the Promkanal valley, the formation of secondary solonchaks was recorded, the salinity level and chemical composition of which depend on the composition of discharges and the distance from the water. In the riverine part of the floodplain, a strong salinization of the surface layers of soils with alkaline salts, which are toxic to plants, was revealed. The vegetation suppression and the absence of humus accumulation were detected. It has been established that the degree of salinity decreases with distance from the waters, and the main salt-containing ions are sulfates, sodium and calcium. Areas for improving the soil cover due to the watering of the Promkanal were marked.

The nature protection measures performed within the national project "Ecology" on the lake system "Chaika" were analysed, the flooding status of the floodland before and after the measures implementation was compared with the equivalent special spring release. A positive effect in increasing the floodland area was confirmed. The chemical analysis results of water and composition of bottom sediments were presented. The bottom sediment was found fertile to be classified as calc-sapropel.

The results of comprehensive assessment of the qualitative composition of groundwater, used for water supply in the city of Saki of the Republic of Crimea, are presented. The parameters, for which the excess of the maximum permissible concentrations was mainly recorded, include: mineralization, total hardness, content of chlorides, nitrates, magnesium, boron and selenium. For all wells, used for water supply in Saki, the value of integral indicator of drinking water danger exceeded 1, which indicates the need to develop and implement a list of measures, aimed at improving the composition of water resources. To do this, it is advisable to provide water treatment in the form of desalination of water using reverse osmosis technology.