The paper presents an analysis of the methods for the chemical modification of biochar. The characteristics of acid and basic modifications, modifications with hydrogen peroxide, sulfonation, amination, impregnation with metal oxides, and magnetization are examined. It is demonstrated that the method of modification, the parameters of the technological process, and the nature of the modifying agent all exert an influence on the chemical composition, structure, porosity, pore size, and total specific surface area of the modified coal. The combination of methods, technological parameters, and modifiers allows for the production of sorbents for wastewater treatment based on biochar with specific properties for the sorption of certain groups of different pollutants.

Keywords: biochar, chemical modification, sorption properties, porosity, pore size

The paper presents a new approach to assessing the level of contamination with heavy metals of the soil-like fraction from landfills using Monte Carlo simulation using the example of landfills located within the borders of Volgograd.It was found that with a probability of 36.2%, the contamination level of a soil-like fraction from the landfill located in the Voroshilovsky district will correspond to moderately hazardous, and with a probability of 63.8%, hazardous. It is economically justified to isolate a soil-like fraction with a low level of pollution to detoxify it and further use it in the territory reclamation. For a soil-like fraction from landfill located in the Traktorozavodsky district, the pollution level was determined as extremely hazardous and hazardous with a probability of 87.1% and 3.1%, respectively. It is shown that a useful and usable part cannot be isolated from a soil-like fraction. A soil-like fraction must be neutralized and placed at waste disposal facilities.The presented approach is a useful instrument for pollution level assessment of a soil-like fraction, which can increase the accuracy of an estimate and the management effectiveness of a soil-like fraction during landfill development.

Keywords: landfill, soil-like fraction, heavy metals, pollution level, Monte Carlo method, modeling

The paper presents the results of experimental studies on the effectiveness of complex electrochemical treatment using hydrogen peroxide for water disinfection. The effectiveness of the method for sanitary-indicative microorganisms has been confirmed. The most significant parameters for the disinfection process have been identified and a mathematical model has been developed based on them, which makes it possible to design industrial disinfection devices that are separate modules.

Keywords: disinfection of water, electrochemical methods, hydrogen peroxide, bactericidal effect, disinfection

The purpose of this work is to determine the possibility of using a fine fraction (screening) of landfill waste located on the western outskirts of Volgograd as recultivating soil. The following priority indicators were determined in the selected samples: hydrogen index (pH), the content of benz(a)pyrene, petroleum products and groups of elements related to heavy metals: mercury, cadmium, arsenic, lead, zinc, nickel and copper, namely forms extracted with acid and buffer solution and ammonium acetate with a pH of 4.5. Excess of normative values in the samples was noted for such toxicants as cadmium, nickel and copper. The value of the total indicator of chemical pollution Zc without taking into account the toxicity coefficient was 30.03, and taking into account - 46.34, which corresponds to the categories ""moderately dangerous"" and ""dangerous"". It is determined that the small fraction of landfill masses belongs to the 4th class of waste hazard - low-hazard. Direct use of sieving as a soil recultivant is not possible. It is necessary to carry out measures to detoxify it. Due to the presence of components with carcinogenic properties, acceptable detoxification directions are extraction or encapsulation of heavy metals.

Keywords: landfill masses, fine fraction, chemical pollution, hazard class

This article presents the results of the study of pollution of components of the natural environment (air, soil, water) and wastes located in the territory of the landfill near the village of Samofalovka, Volgograd region, and carried out an assessment of the accumulated environmental damage.

Keywords: Landfill, accumulated environmental damage, pollutants, exposure level

This work relates to the field of chemical technology and information can be used in the industry to protect against biofouling water recycling systems of energy and petrochemical enterprises.

Keywords: treatment, processes, water, corrosion, fouling, reagents, methods, coolant, electrical treatment, bioculture

The use of sunflower husk waste allows to solve the problem of utilization of agricultural waste and obtaining adsorbents for wastewater treatment of industrial production from ions of heavy metals, in particular copper. Studies on the evaluation of the adsorption capacity of materials have been carried out and choose the optimal method of manufacturing the sorbent.

Keywords: husks of sunflower, vegetable adsorbents, waste water, heavy metal ions, melanin