An engineering solution was proposed for the regeneration of electrolytes used in plasma-electrolytic treatment by modernizing the electrolyzer chamber through the installation of a gas exhaust trap and directing the captured gases back into the electrolyte solution. The methods used include the study of the structural-phase state of the surface layers of steel samples, microhardness measurements, and chemical analysis of the solutions. It was shown that adjusting the electrolyte composition using exhaust gases leads to stabilized treatment conditions and consistent reproduction of the achieved characteristics of the steel surface layer (structural-phase composition and microhardness of the surface layers) during prolonged use of the electrolyte. It was concluded that this engineering solution can reduce exhaust gas emissions into the atmosphere and enhance the environmental safety of plasma-electrolytic treatment.

The technological possibilities for organizing a low-waste, resource-efficient production of the protein additive Gaprin from natural gas were examined. Results obtained from experimental and pilot-industrial installations during commissioning tests were presented. The flow chart of the technological process was presented, design features and technological regimes in three production zones were studied: the drying agent (DA) drying zone, the gas flow circulation zone, and the zone of rational use of liquid flows.

Approaches to managing fire risks at municipal solid waste (MSW) landfills were considered, based on the mathematical identification of volumetric fire parameters using model calculations of burn rate and fire size. Critical parameters for the ignition of surface waste layers and the conditions for their development into full-scale volumetric fires in the ground layer were established. An automated monitoring and fire prevention system for MSW layers at landfills was developed. It includes a network of equidistant autonomous moisture and temperature sensors, as well as biogas accumulation sensors. The use of unmanned aerial vehicles was highlighted as a promising method for both real-time monitoring and emergency extinguishing of surface fire outbreaks.

One of the most effective methods for protecting steel structures from aggressive marine environments, fouling, and corrosion—using contact-type protective coatings—was studied. The efficiency of biocide mass transfer from the coatings into the surrounding seawater was improved. Ecofriendly antifouling coatings were developed, featuring an insoluble matrix composed of biocidal systems containing porous fillers (thermally expanded graphite, vermiculite) to protect the surfaces of structures. It was shown that various modifications of the fillers in these contact-type antifouling coatings with anticorrosion properties help reduce biofouling and can significantly extend the service life of the protected structures.

A study was conducted to visualize the speciation of heavy metals—copper (Cu) and nickel (Ni)—in contaminated bottom sediments and their influence on the cleaning process using vibrating screens. It was shown that the metals in the studied samples were primarily present in the form of sulfides: either with dense cementation by clay material along the entire contour of the aggregate, or with localized (point) cementation by clay particles. A dense cementation effect of Cu and Ni aggregates along the contours on the surfaces of quartz and potassium feldspar grains was observed in samples with elevated organic matter content. It was found that low organic matter content resulted only in localized cementation of heavy metals. The average size of all observed nickel and copper sulfides did not exceed 10–15 μm. It was concluded that increasing the mesh size of the screen leads to a rise not only in the amount of heavy metals retained but also in the volume of soil passing through the screen. This may pose challenges due to the large-scale removal of the undersized ("clean") soil fraction, resulting in high transport and disposal costs.

The kinetics of sorption of copper ions on sorbent obtained from solid residue of pyrolysis of worn tyres using different kinetic models has been investigated, the mechanism of sorption and limiting stage of the process have been established. It was found that the kinetics of copper sorption is best described by pseudo-first and pseudo-second order equations with R2 values of 0,9547–0,9971. The process is analyzed using the Yelovich equation and its chemisorption mechanism is determined. . It was found that at the concentration of copper ions less than or equal to 1.0 mg/l the rate of chemisorption is limited by external diffusion, and at higher concentrations by chemical reaction on the sorbent surface, as well as availability of active centres. The possibility of application of solid residue of pyrolysis of worn tyres after its acid-alkali processing for purification of solutions from copper ions is proved.

The mechanisms of reactions between the hydration products of Portland cement and the components of acidic fly ash were studied. The role of crystallographic defects in alite grains on their hydration activity was noted. It was concluded that solid waste from coal combustion (fly ash) can be used as a partial replacement for Portland cement in concrete production, which would lead to reduced CO₂ emissions and a decrease in fly ash accumulation in landfills.

Sources of chitosan, traditional and industrial methods of its production, and recent advances in the study of its physicochemical properties were analysed. The structure of chitosan and its application in removing dyes and metal ions from wastewater and groundwater were discussed. The potential use of chitosan for the cleanup of oil spills on water surfaces and the possibility of reusing chitosan and its derivatives, along with the need for proper disposal of spent chitosan-based sorbents, were also noted.

Based on statistical data from 2017 to 2023, the distribution of oil and petroleum product spills across soils, vegetation cover, and administrative districts of the Republic of Bashkortostan was analyzed. The main causes, geography, and scale of pollution incidents were identified. The spatial distribution of spills was determined, and regions with the highest frequency of such incidents and zones of increased environmental risk were highlighted. The necessity for enhanced environmental monitoring and the development of effective strategies to prevent spills and minimize their consequences was emphasized.

An original methodology for justifying standards for permissible discharge (PDS) of pollutants from an organized source of water disposal was proposed. An approach was presented, based on maintaining the water quality class, defined by the value of the specific combinatory water pollution index at the monitoring cross-section after wastewater discharge. The problems arising in the application of the current methodology for calculating the PDS of pollutants were considered, the results of testing the methodology for substantiating threshold concentrations for calculating the PDS of pollutants and data on calculating the PDS of pollutants from an organized source of wastewater disposal of a chemical plant were presented.