Kryzhanovska Y. "Protection of aquatic ecosystems from contamination by mineralized wastewater"

The dissertation work is devoted to the study of the protection of aquatic ecosystems from pollution by mineralized wastewater. The problem of providing the population of our country with high-quality, suitable drinking water is acute, especially at the present time, during the war. The situation is also difficult in the eastern regions of Ukraine, where, due to the large-scale development of industry, a significant anthropogenic load on water bodies was observed. Today, the situation has become more complicated due to the intensity of hostilities. The situation is no less complicated in the southeast and south of Ukraine (seaside areas), where water mineralization is increased due to natural factors. The problem was significantly aggravated by the war, which caused the destruction of water use systems, the destruction of the Kakhova HPP and the destruction of the Kakhova reservoir. To a large extent, the pollution of natural water bodies is caused by discharges of highly mineralized mine waters without proper treatment, wastewater from industrial enterprises, communal facilities, and wastewater generated at agricultural facilities. Often, saline concentrates and eluates, which are formed during the purification of natural waters, are also discharged into natural reservoirs without purification. Thus, the creation of effective, perfect and effective low-waste technologies for desalination of natural waters is an important and urgent scientific and technical task. The importance of low-waste technologies, which make it possible to obtain useful products that can actually be used for industrial purposes, should be emphasized. The purpose of this dissertation was to ensure the successful implementation of modern water desalination technologies by solving the problem of processing salty concentrates formed during water purification, with obtaining useful products, the implementation of which will significantly reduce the total costs of water purification and conditioning. The results of the dissertation work are presented in four sections and appendices. The first chapter of the dissertation describes modern scientific methods of desalination of natural waters and purification of polluted wastewater by electrochemical, membrane methods, as well as concentration and desalination methods. The relevance and importance of technological principles of low-waste production, the possibility of obtaining modern and effective coagulants, disinfectants as secondary products of water purification and their use as promising reagents for water purification have been studied. Well-known methods of water demineralization are studied and described, their advantages and disadvantages are also outlined, and prospects for their development are highlighted. The second section of the dissertation presents the objects and methods of research, which include the description, characteristics, physicochemical properties of those environments, materials and reagents that were used and given in the following sections of the dissertation. The objects of the study were Dnipro water, as well as model solutions. This section describes reagent methods for cleaning concentrates of baromembrane desalination, as well as electrochemical methods for processing concentrates. Techniques for controlling physical and chemical processes and determining the concentrations of substances in water are described. In the third chapter of the dissertation work, the basic principles of disposal of concentrated waste produced as a result of baromembrane water desalination were experimentally conducted, and also analyzed and studied. The main conditions and aspects of effective reagent purification of mineralized waters from sulfates using alumina production waste were studied. The conditions of obtaining oxidized chlorine compounds in two-chamber and three-chamber electrolyzers were experimentally studied, taking into account the influence of current density and chloride anion concentration on the efficiency of the process. In the fourth chapter of the dissertation, the main aspects of electrochemical purification of baromembrane water desalination concentrates were experimentally investigated using aluminum and iron anodes to obtain aluminum and iron coagulants. The effect of current strength and process time on the degree of solution purification was investigated. The effectiveness of the obtained coagulants, which were obtained from water treatment waste, was evaluated. We compared the performance of the newly obtained coagulant with existing ones on the market, and made sure that their performance is satisfactory and effective. The production of coagulants from water treatment waste is a promising, economically profitable and interesting area of environmental protection.