FORMULATION AND IMPROVEMENT OF TECHNOLOGICAL SOLUTIONS FOR WASTEWATER TREATMENT OF AGRICULTURAL REPAIR ENTERPRISES

The article presents the main production cycles of engine repair at a repair and mechanical plant. The main production cycle of engine repair at the repair and mechanical plant consists of external steaming of the unit in the steaming chamber with the discharge of the formed effluent into the pre-fabricated well. Next the disassembly of the en-gine into individual components is carried out, then they are cleaned in cross washing machines with periodic discharge of spent detergent solutions into the prefabricated tanks. After restoration of details the assembly of the diesel engine and its test on stands is carried out. The necessary parts are electrochemically galvanized, chrome-plated or coated with iron. Several local wastewater treatment schemes on the plant with utilization of valuable components and their reuse are offered. Wastewater and waste process solutions are conventionally divided into low-concentrated and concentrated. Low-concentrated wastewater includes effluents from the diesel test site, flushing water from plating baths, and discharge of a revolving diesel cooling system. A scheme for wastewater treatment from petrole-um products and substances in the form of suspensions has been developed and researched, which allows reusing wastewater from the re-verse water supply to the diesel test site. The schematic diagram of the reverse water supply of the diesel test area will consist of a column electrical flotation coagulator, contaminated water collectors, saturators and pumps. A scheme of electrochemical purification of waste detergents has been developed, which includes receivers of detergent solution, preliminary settling of coarse impurities, column electrical coagulator-floater with soluble aluminum electrodes, electrolyte collection. The peculiarity of the device is the operation of the electrode system in a pure electrolyte, which eliminates the possibility of contamination and passivation of electrical and chemical processes. The electrically generated coagulant is dosed into the reaction chamber, mixed with the detergent solution, coagulates and floats the contamination, which allows to extend the service life of the detergent solutions in two or three times.

MODERNIZATION OF WATER SUPPLY SYSTEMS FROM SURFACE SOURCES

Surface water bodies, which are sources of drinking water supply, receive a significant amount of pollution from wastewater. This negatively affects the ecological condition of water resources and poses a threat to the health and sanitary well-being of the population. The main pollutants of surface sources are: sewage of economic-fecal and industrial sewage, which contain organic pollutants, surfactants, heavy metal ions; oil products coming from industrial sites and urban areas; effluents from livestock farms and storage ponds of production waste; washing of mineral fertilizers and pesticides from agricultural lands. Adjustment of surface springs additionally affects the deterioration of water quality in them. Therefore, existing water treatment technologies may not always provide the required degree of drinking water purification. According to monitoring studies, more than 38% of water samples taken at centralized water supply facilities did not meet regulatory requirements. This situation encourages the search for ways that would create conditions for more efficient operation of water supply systems. Modernization of existing water supply facilities and application of new water treatment technologies can help solve the problem. The article illustrates constructive schemes of shore and channel water intake and treatment facilities, the use of which makes it possible to reduce the dirt retention load on the main treatment facilities, increase the reliability of fish fry protection and improve the ecological condition of reservoirs at water intake sites. For effective removal of organic matter at water treatment plants, it is advisable to use bioreactors and contact-clarifying filters. Such solutions allow not only to increase the productivity of the water treatment plant, but also significantly reduce its construction cost, simplify the operation of facilities and reduce annual operating costs.

FERRITATIVE WASTEWATER TREATMENT FROM CHROMIUM (VI) COMPOUNDS USING ELECTROMAGNETIC PULSE ACTIVATION

Issues related to the prospects of implementing the latest technologies aimed at achieving energy efficiency in the field of water supply, resource conservation in material-intensive processes at industrial enterprises and prevention of environmental pollution are considered. A study of ferritative wastewater treatment from chromium compounds, which belong to the first class of danger. The efficiency of thermal and electromagnetic pulse activation of the process is compared. Appropriate experimental setups were developed and the main parameters of the purification process were studied and determined: the ratio of iron (II) and chromium (VI) ions, magnetic field strength, frequency of electromagnetic pulses, ferritization process duration, temperature and pH of the reaction mixture. The expediency of using electromagnetic pulse activation of the reaction mixture by passing electromagnetic pulses through the reaction mixture has been studied and scientifically substantiated. Rational values ​​of the strength and frequency of the electromagnetic field when using this method of activation, which are 0.01 - 0.14 Tl and 1 Hz, respectively, as well as the ratio of concentrations of heavy metal ions Fe2 + / Cr6 + = 10/1 for washing water chrome plating line . It is shown that purified water meets the requirements of category 1 when reused in production. The results of X-ray diffraction analysis of ferritization sediments showed that stable crystalline phases, such as chromium ferrites and magnetite, are formed with increasing magnetic field strength. The chemical resistance of sludge allows them to be safely disposed of. It is established that this method of electromagnetic pulse activation is not inferior to thermal, and the technical and economic calculations confirmed a significant reduction in industrial costs in its application

CALCULATIONS OF SHORT PIPELINES TAKING INTO ACCOUNT THE FLOW STABILIZATION

Analyzing the existing dependences on the calculation of short pressure pipelines in turbulent mode, significant shortcomings of these recommendations were identified. A physical model of motion is proposed, which explains the processes occurring in the area of stabilization after local resistance and allows to establish the factors influencing its length.Experiments on pipes with different roughness and different pipeline fittings made it possible to analyze the change in kinematic characteristics in the area after resistance. Studies have shown that in short pipes, the length of which is less than the length of the stabilization section, there are less pressure losses than in the calculations by the usual method, when there are simply local and length losses. Dependencies and graphs are given that take into account the mutual influence of local resistances in the case of their location at a distance less than the stabilization area. The proposed recommendations make it possible to make more informed economic decisions when designing short pressure pipelines of various water supply systems.

ANALYSIS OF THE RESULTS OF PERFORATED DRAINAGE PIPELINES CALCULATION IN THE PRESENCE OF TRANSIT FLOW RATE

A method of calculating the error that occurs when determining the flow rate in the final section of the pressure perforated drainage pipeline when it passes transit flow rate, based on the analysis of differential equations describing the fluid motion with variable flow rate in such pipelines is proposed in the paper. The analysis is presented in dimensionless form. The impact of transit flow on the main flow is estimated using the values ​​of the drainage pipeline resistance coefficient ζl and the generalized parameter of the perforated drain A, which takes into account its constructive and filtration characteristics. The obtained calculation formulas are quite simple and easy to use. The proposed method allows to perform calculations of drainage pipelines that operate in the presence of transit flow rate, according to the method of these pipes calculation that dispose drain water without passing transit. Herewith, the possible error, which includes in the calculation results, determines. To illustrate the obtained dependences, the corresponding graphs are given in the paper. The results of the analysis allow to determine the limits within which a simplified method of calculating these pipes can be used and the error, that occurs, can be estimated

INTENSIFICATION OF IRON REMOVING OF LOW ALKALINE GROUNDWATER

The problem of providing humanity with quality drinking water is exacerbated in the modern world. According to international organizations, a half of the world's population by 2025 will live in areas with significant water shortages. The sufficient standard of living and environmental safety is one of the citizens’ rights defined by the main law of Ukraine, which provides for the provision of quality drinking water in the required amounts and in accordance with established standards for the quality of drinking water. The Cabinet of Ministers of Ukraine has approved the concept of the state target social program "Drinking Water of Ukraine" for 2022-2026 for this purpose. The unsatisfactory state of water quality in Ukraine is associated with moral and physical depreciation of main resources, underfunding of water supply and sewerage industry. The situation is complicated by the lack of qualified personnel in rural areas. A large part of the inhabitants’ rural settlements use groundwater aquifers for their drinking purposes, which often contain excessive concentrations of total iron. The water treatment facilities were built according to standard designs using non-reagent methods for water iron removal in small settlements. The practice of individual treatment plants operation has shown their low efficiency, due to the unreasonable use of such methods. The improvement of existing water treatment schemes should be carried out taking into account the peculiarities of the physicochemical composition of water and the use of existing water treatment equipment. The purpose of the work is to improve the technological scheme of water iron removal and improve the quality of the filtrate. It is established that the reason for the unsatisfactory operation of treatment plants is due to the low alkalinity of groundwater. The rational types of alkalizing reagents and their calculated doses are substantiated by the results of experimental studies, the dependences of changes in the hydrogen index on the type and dose of reagents, residual alkalinity of water, the efficiency of water iron removal.

SLOPE STABILITY ASSESSMENT OF THE UPSTREAM SLOPE OF THE DRY MOUNTAIN FLOOD CONTROL RESERVOIR DURING THE FLOOD

The flood control is one of the priority goal for successful economic activity on the areas that are periodically suffer from floods. Such areas are the mountainous regions of the Ukrainian Carpathian Mountains. Floods on the mountain rivers are repeated several times each year, and are characterized by the sudden water level rise with almost the same rapid decrease of the water level. Active flood protection measures include dry mountain flood control reservoirs, the principle of which is to transform part of the flood runoff and to accumulate water for the short time in the the artificial reservoir, with followed rapid emptying to the minimum level. The complex hydraulic regime is formed in the body of the dam which forms the flood control reservoir during the flood, that is different from the operation of the water permanent reservoir. The design of the flood control structures is car-ried out in accordance with Ukrainian building codes for the construction of the water reservoirs with constant water level, and require testing the stability of the downstream slope for the maximum water levels under steady state seepage conditions and assessment the upstream slope stability during the water level decreasing from the maximum level calculated in the steady state condition, these calculations do not correspond to the real seepage processes in the body of the dam of the dry flood control reservoir. Therefore, the purpose of this work is to determine the necessary boundary conditions of the flood control reservoir operation and upstream slope stability assessment by the limit equilibrium method. In the article the operation of the dry mountain flood control reservoir was analysed and found that the dam was characterized by two states: dry reservoir with water minimum water level and variable position of the seepage curve in the core and the upstream prism during the flood. The main factors influencing the upstream slope stability are the physical and mechanical properties of the soil, the laying of the slope, the period of time when the high-water level is maintained and the intensity of water level dropping. The upstream slope stability was evaluated by the Morgenstern & Price and Ordinary methods on the Slope/w software package. After the first 25 hours of the flood (period of high-water levels and the next water level dropping) the Safety Factor evaluated by limit equilibrium methods began to decrease, and reached the minimum value during the greatest seepage curve gradients at the time between 45 and 50 hours. Slope stability calculations by the limit equilibrium method were compared with the results of calculations performed by the SRM method, the values ​​of the Safety Factor and the way of their change during the flood evaluated by Ordinary and SRM methods almost coincide, which indicates the reliability of the results obtained by different methods of slope stability analysis

CARBONIZATION OF CONCRETE AND CORROSION OF REINFORCEMENT OF REINFORCED CONCRETE STRUCTURES OF UNDERGROUND SEWERAGE SYSTEMS

The process of carbonization of concrete with different ratio of water to cement (W/C) was studied, and the influence of the environment on corrosion damage of reinforced concrete reinforcement was studied. The results of the study of carbonization of concrete on specially prepared model samples of concrete with a size of 250x250x250 mm with an exposure period in NACE solution for 500 days without external load are presented. Measurements of corrosion damage of reinforcing rods, which were placed inside concrete cubes, were performed. The method of estimating the amount of carbonization of concrete and corrosion of reinforcement is described in detail in known scientific papers. The obtained data testify to the active carbonization of concrete during the whole exposure period of the samples in NACE solution, however, concrete prepared at the ratio W/C = 0.5 and 0.6 is particularly significant in terms of carbonization intensity. Concrete with a ratio of W/C = 0.7 is less susceptible to damage. Moreover, a similar trend is observed for corrosion of fittings. This is due to the fact that the increase of the aqueous medium in the concrete mass facilitates diffusion processes of delivery to the reactive zone of chemically aggressive ingredients such as carbon dioxide, chloride ions, hydrogen, sulfur, sulfate ions, various types of bacteria and the like. The kinetics of concrete carbonization and corrosion of reinforcing bars in chemically aggressive NACE medium depending on the exposure period of the samples in the model solution was experimentally studied. It is established that with the increase of the water-cement ratio W/C from 0.5 to 0.7, the depth of carbonization and the layer thickness of corrosion products increase sharply. The flooding of the surface layers of the reinforcement and their strong embrittlement in the process of long-term operation of the reinforcement in the structure of reinforced concrete, which causes a decrease in crack resistance in general of reinforced concrete structures. The degradation of reinforcing steel during long-term operation in aggressive environments, which leads to premature corrosion damage to the reinforcement with subsequent destruction of the structure, was investigated experimentally with the involvement of high-precision metallographic equipment.

INVESTIGATION of COLOR REMOVAL in REAL TEXTILE INDUSTRY WASTEWATER with MEMBRANE BIOREACTOR-ACTIVE CARBON SYSTEM

The textile industry is an industry that consumes large amounts of water during production, contains various chemicals in its wastewater, conventional treatment methods are insufficient to reduce the wastewater pollution level, and has colloidal substances and color problems. Membrane bioreactor systems provide high efficiency in the treatment of textile wastewater and dyestuff removal. Removal of dyestuffs and turbidity in real textile wastewater by using a laboratory-scale membrane bioreactor system was studied. Chemical precipitation was not applied before the biological treatment for the removal of color and other pollutant parameters. A hollow fiber microfiltration membrane module was used in the system. Then a combination with an active carbon filter was created to take the color removal to a higher level. The development of the microorganism composition adapted to the textile industry was observed in the biological reactor. The system was operated with an endless sludge age and a hydraulic retention time of 24 hours. Color measurement transparency index parameter DFZ (DurchsichtsFarbZahl) was measured in a spectrophotometer at wavelengths of 436, 525, and 620 nm (nanometers) according to EN ISO 7887 standards. In the microfiltration permeate water, the color removal were found in 436 nm: 91-95%, 525 nm: 94-98%, 620 nm: 96-99%, and in activated carbon permeate water, the color removal in 436 nm: 96-99% at 525 nm: 95-99%, 620 nm: 96-99%, respectively. Due to the physical separation of the membrane, which is the simplest definition, high efficiencies in color removal have been achieved in the system. The activated carbon system combined with the membrane was found higher efficiency in color removal than the microfiltration output.

FORECASTING THE GROUNDWATER TREATMENT PROCESS IN A BIOREACTOR USING FERROBACTERIA

The monitoring of water quality parameters in 90 settlements of eight regions of Ukraine made it possible to state that groundwater is a complex multicomponent system. Existing deironing stations using simplified aeration-filtration technology are not able to remove Fe (II) compounds from water in the presence of humic complexes. Therefore, in modern conditions, the urgent task is to intensify their work through the introduction of new technologies, including biotechnology with the development of appropriate mathematical models. It is shown that much less attention was paid to modeling the kinetics of groundwater treatment processes in bioreactors than to traditional physicochemical methods, for which modern mathematical models were developed. The aim of the work is to develop a mathematical model of the kinetics of the process of groundwater treatment in bioreactors. The mathematical model is represented by the Cauchy problem for a nonlinear system of differential equations in partial derivatives of the first order. The system of the Cauchy problem consists of five equations with five unknown functions, which describe the distribution the concentration of ferrum cations, bacteria and the matrix structures in two phases (movable and immobilized) both in space and time. The inverse influence of the characteristics of the process, in particular, the concentration of matrix structures in the inter-pore space, as well as characteristics of the medium with the help of coefficients of mass exchange and porosity, were taken into account. The model allows determining the optimum operation time of a bioreactor between washings