MAIN CHARACTERISTICS OF WASTEWATER, ITS TREATMENT AND RETURN TO THE ECOSYSTEM

The article examines the main characteristics of wastewater, their types, pollutants, sources of organic substances in their composition and their effects on wastewater, as well as types and problems of treatment. Wastewater is considered to be water discharged into the natural environment (ecosystem) after being used for domestic or industrial purposes or as a result of atmospheric precipitation, contaminated with various types of mixtures (mechanical, chemical, biological). These waters require treatment before being discharged into the natural environment to prevent pollution of soil, water bodies and air. It is known that the contact of wastewater with natural systems, in general, negatively affects the ecosystem, ultimately creating conditions for human health and the destruction of natural biodiversity. Therefore, studying the conditions of their occurrence and the comprehensive impact of their expected negative consequences on the natural environment is considered to be one of the important issues. The main sources of wastewater are domestic water, industrial water, commercial wastewater, rainwater, and groundwater or surface water entering the sewage system in various ways. They are distinguished by their physical, chemical and biological properties. Depending on these properties, various pollution characteristics of the natural environment arise. Among these pollutants, organic pollutants, mainly contained in waste generated in connection with human domestic and industrial activities, occupy an important place. For example, pollution with domestic water occupies 60-70% of the pollution with organic substances. In order to reduce the negative impact of wastewater on the environment, as well as to ensure its subsequent return to the ecosystem, the process of cleaning it from pollutants is carried out. Wastewater treatment is the process of removing pollutants from it so that it is safe for discharge into the environment or reuse. The treatment process usually includes several steps, including advanced treatment, primary treatment, secondary treatment, tertiary treatment. Problems associated with wastewater treatment include the high costs required to construct and operate wastewater treatment plants, the need for qualified operators to operate wastewater treatment plants, and potential environmental impacts such as the release of harmful pollutants into the air and water. Keywords: Wastewater, pollutants, ecosystem, wastewater treatment.