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 article presents the study results of a soil-like fraction contamination at a landfill located on the territory of the Traktorozavodsky district of Volgograd with heavy metals. The soil-like fraction's pollution level was assessed using a cumulative chemical pollution index (Zc) and its modifications. It was determined that the contamination levels with heavy metals are dependent on a used cumulative chemical pollution index modification. The use of the average geometric values of a cumulative chemical pollution index (Zc) is preferred for a pollution assessment of a soil-like fraction. Because the pollution level of a studied soil-like fraction was assessed as hazardous, its use as a recultivation material can only be permitted after a detoxification.The main pollutants in the soil-like fraction are cadmium, copper, and nickel.

Keywords: landfills, soil-like fraction, heavy metals, pollution level

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