The results of studies on purification of gas emissions (GE) with a granular sorbent based on carbonate sludge from chemical water treatment are presented. The choice of conditions for modifying carbonate sludge with a sodium silicate solution to obtain a granular sorbent has been experimentally substantiated. It is confirmed that the data obtained correspond to and complement the theoretical principles and laws of colloidal and physical chemistry, industrial ecology, which is important for the choice of engineering solutions. A technological scheme for adsorption purification with a regeneration cycle of granular sorption material based on carbonate sludge from the Naberezhnye Chelny CHPP has been developed. It was concluded that the efficiency of GE treatment increased by up to 99% when using the proposed measures. The environmental and economic indicators of the use of the resulting granular sorbent in the scheme for purifying GE from SO₂ in production of sodium hydrosulfite have been calculated. The prevented environmental harm to the environment from the use of the proposed technology has been determined, as well as the cost of production of granular sorption material and the payback period.

To solve the issue of gas purification, a new dust collecting device with arc-shaped elements has been proposed. A feature of the device is noted, which consists in the capability of changing the flow area at its inlet by varying the number of rows of arc-shaped elements and their height, which makes it possible to select the inlet gas velocity at which the separation efficiency is maximum. The results of numerical modeling of the process of capturing solid particles from gas for various design solutions and process parameters of the unit are presented. It has been found that the high efficiency of a device with arc-shaped elements at a low pressure drop (no more than 380 Pa) is achieved by creating an arranged wave-like structure of the gas and dust flow, on the basis of which the centrifugal forces of high values arise at relatively low gas velocities at the inlet (0.25–2 m/s). A conclusion was made on the optimal design of the device, which has a height of arc-shaped elements of 250 mm and the number of their rows is 12 pcs.

Methods for installing the harbour booms both with and without a support rope are considered and their features and disadvantages are highlighted. An improved method for installing a harbour boom along a support rope is presented, which eliminates the shortcomings of existing methods. A detailed description is provided, as well as the results of experiments on installing the harbour booms using this method.

An analysis of the resource potential of macroalgae wash-outs onto the Baltic Sea coast has been performed. A critical review of the applications of polysaccharides extracted from Furcellaria lumbricalis macroalgae wastes washed ashore is presented. Optimal extraction conditions have been established to ensure maximum yield of polysaccharides. It is recommended to use alkaline hydrolysis with potassium hydroxide 0.1 M, process time is 60 minutes. Recipes of biopolymer films with the necessary physical, mechanical and antibacterial properties have been determined. It was concluded that the production of biofilms with antibacterial properties with the addition of vegetable oils is promising. Their use with application directly to the product will provide a longer shelf life without significant changes in organoleptic properties.

An analysis of approaches to arranging the air quality control in large cities with developed industry is presented. The main results of atmospheric air monitoring using a mobile environmental laboratory are shown, and the ways to improve its activities are proposed. It was established that often no excess of the MPC was observed, but the values were recorded that went beyond the upper limit of the Shewhart control chart, indicating that the population felt a change in the content of pollutants in the atmospheric air.

A set of issues related to the cleanup of oil and petroleum product spills in sections of the underwater crossing of the main pipeline has been considered. The special importance of timely cleanup to emergency oil and petroleum product spills was noted. Various methods for cleanup of oil and petroleum products spills on sections of main pipelines, their operating principles, technical and process features and equipment used, as well as the advantages and disadvantages of these methods have been analyzed. A diagram of an emergency situation has been constructed, and various classifications of methods for localizing the oil spills in the waters of rivers and lakes through which the main pipeline passes are presented. An optimal decision-making algorithm has been developed on the choice of method for localizing an emergency spill of oil or its processed products at an underwater crossing of a main pipeline.

The effect of natural ameliorants and industrial waste on the filtration capacity of solonetzes and the process of their desalination and salinization in relation to soils neutral and sulfate soda salinity in the south of the Tyumen region has been studied. The conclusion is made about the feasibility of using phosphogypsum as waste for solonetzes reclamation and the need for field testing promising coagulants in the form of industrial waste.

The possibility of using wastewater in the Republic of Crimea for irrigation of agricultural crops was considered, the volume of which in 2021 amounted to over 50 % of the total water intake for national economic needs from all sources. It is shown that a significant part of the wastewater after its additional purification and water treatment can be used in irrigated agriculture in the Azov Sea basin, where there are agricultural lands prepared with irrigation. It is concluded that the use of other wastewater will require reconstruction and modernization of treatment facilities, drainage systems and the creation of utilities for the accumulation of wastewater, its post-treatment for irrigation purposes and transportation to irrigation systems.

The possibilities of economic justification for activities related to the treatment and disposal of sewage sludge are considered by assessing their effectiveness and efficiency. Two assessment methods are proposed: based on integral target indicators and based on a risk-based approach. A combined assessment of the effectiveness and efficiency of production and investment program activities is recommended. It is based on the main regulatory documents regulating the field of wastewater disposal. It is noted that the use of this approach will provide regulatory and regulated institutions with an effective mechanism for economic argumentation of the process costs related to the treatment of sewage sludge.

The influence of oil pollution of groundwater in a karst region onto the bacterial component was studied. It has been established that bacteria are present in groundwater in an amount of 10³–10⁶ cells/ml. Representatives of the genus Arthobacter, Microbacterium, Rhodococcus, Williamsia (phylum Actinobacteria), Achromobacter and Pseudomonas (phylum Proteobacteria), Bacillus and Brevibacteria (phylum Firmicutes) were revealed. The state of the microbial component of the studied groundwater was analyzed according to the scale of environmental modifications. It was concluded that, with the exception of the release of groundwater at a site 320 m away from the oil field facilities, bacteriocenoses are in a state of "anthropogenic ecological stress".