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Документ Відкритий доступ Biotransformation of wastewater production of bakery yeast with biogas generation(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Bublienko, N.; Zakharova, R.; Stetsenko, N.Baking yeast enterprises are a source of environmental pollution by concentrated wastewater. They are usually diluted with water and discharged into sewerage. It is rational to use methane fermentation, which will ensure the removal of pollutants and make the process cost-effective through the use of biogas and digestion. Therefore, it is relevant to study the question of the influence of fermentation parameters on the cleaning efficiency. The aim of the work is to study the methane fermentation of yeast production effluents in a continuous mode. Objectives: analysis of solving the problem of wastewater treatment of yeast plants, study of the influence of process parameters (dilution rate, addition of cobalt salts) on the efficiency of treatment; gas generation; vitamin production. Initial COD of effluents 4500 mg O2/dm3 , pH 6. Cultivation regime – continuous, dilution rate 4,1-10–3, 6,2-10–3, 8,2-10–3, 12,4-10–3 hours–1. Cleaning efficiency 78,9 %. High values of dilution rate cause overload of activated sludge, which leads to reduced cleaning efficiency. The presence of cobalt also has a depressant effect. A significant amount of biogas (up to 5,2 dm3 /dm3 ) is produced with a high content of methane (up to 85 %), which is an alternative fuel. As the dilution rate increases, the biogas and methane content decrease. With increasing dilution rate from 4,1-10–3 to 12,4-10–3 hours–1, biogas decreased from 1,11 to 0,94 dm3 /g CODloading, and from 1,43 to 1,39 dm3 /g CODfermentation. Similarly to the effect on the depth of purification, the inhibitory effect of cobalt on methanogeneration is observed. Digestion is a valuable fertilizer with a significant content of cobalamin vitamins (up to 95 сg/g). The addition of cobalt salts stimulates the synthesis of vitamins, providing an increase of 26,7 to 51,6 %, improving the ratio between active and inactive forms.Документ Відкритий доступ Determination of patulin in apple puree using LCMS with triple quadrupole detector(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Kuptsova, M.; Shchepak, A.; Slis, A.; Solodovnik, T.Patulin is a high-hazardous mycotoxin formed in apples affected by the fungus. This mycotoxin, when ingested, has the irreversible effect of deteriorating health. Most often, patulin enters the human body through processed apple products or baby food. The countries of the European Union have decided to reduce the level of the maximum residue level of patulin in apples to the lowest that can be measured by analytical instruments. Therefore, the aim of this work is to develop a rapid and sensitive method of patulin determination for the lowest level detection allowed by European law. In this work, patulin was artificially added to apple puree at the level of 10 g/kg for further detection. The analysis was performed on an LC-MS/MS system with electrospray ionization type and a column based on modified silica. The mobile phase used in the analysis was ultrapure water and acetonitrile with the addition of formic acid. Measurement of the quantity of PAT in the sample was performed using MRM transitions. Subsequently, there was a problem of significant inclusion of the matrix on the spectrum, but the problem was solved by using cartridges for cleaning of matrix impurities. As a result, we achieved a successful and accurate result at level of 10 g/kg. A calibration curve was felicitously constructed for five different concentrations. The most important parameters of validation of the method use were determined – reproducibility, repeatability, recovery and linearity. The final result of this work is the development and implementation of a rapid, cost-effective and suitable method for determining patulin at the level of the maximum residue level.Документ Відкритий доступ Development of high-efficiency replacement filters for purification of drinking water on household filter pitchers(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Bolshak, A.; Patalashka, R.; Gudim, N.; Liuts, V.; Shevchuk, O.Water filter pitchers s are the simplest and most affordable devices for local purification of drinking water from centralized and decentralized water sources. The main filter element of such pitchers is a cartridge containing a mixture of sorption materials that are able to absorb certain impurities from the water. However, as previous studies demonstrated, the quality of water, purified with filter pitcher cartridges currently available on the market, does not usually reach the level sufficient to meet the standards for drinking water, which are specified in the document DSanPin 2.2.4-171 -10 "Hygienic requirements for drinking water intended for human consumption", while maintaining compliance with consumer needs. Therefore, the aim of this study is to develop a cartridge for filter pitchers, which would provide high efficiency of purification of tap water in Kyiv from the most common impurities: chlorine, organic compounds and hardness ions. In this work, 5 newly created cartridge samples with different ratios of sorption material content, drainage material density, cartridge filling density, presence or absence of inert material in the loading were studied to identify the impact of these factors on water purification efficiency and water filtration rate, as well as the connection between these parameters. According to the results of the study, a cartridge for a filter pitcher was proposed and determined its the optimal composition. It provides adjustment of tap water composition, namely: reduction by 60 % of the average concentration of chlorine (per 150 dm3 of water), by 15 % - permanganate oxidizability and by 20 % concentration of hardness ions to standard values at filtration rate not less than 0.15 dm3 /min and a resource of 150 dm3. These results were achieved by selecting the optimal ratio of the components of the filter loading mixture and the density of the bottom drainage material.Документ Відкритий доступ Discrete-pulsed energy input in wastewater treatment technologies(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Obodovych, O.; Sabliy, L.; Sydorenko, V.; Pereiaslavtseva, O.; Khomenko, V.Wastewater treatment is an important environmental problem of the national economy of any country. Therefore, increasing the efficiency of wastewater treatment through the use of innovative technologies and equipment is becoming relevant. Basically, for the biological treatment of wastewater from organic and biogenic pollution, aerotanks with different aeration systems are used. The aeration and mass transfer of the mixture of waste water and activated sludge accounts for up to 80 % of operating costs. The article deals with the problems of using thermal physics in wastewater treatment by intensifying the mass transfer process and accelerating the biological oxidation reaction. The intensification occurs due to the impact on the treated medium (waste water) of the input energy by the discrete-pulse method. The method is implemented using new heat and mass transfer equipment, namely a rotary-type aerator-oxidizer (AORT). A diagram of a rotary-type aerator-oxidizer and a technological scheme for biological wastewater treatment using this apparatus are presented. A procedure has been developed for determining the volumetric coefficient of oxygen mass transfer from the gas phase to the liquid phase during biological wastewater treatment. A number of studies have been carried out on the dependence of the concentration of oxygen dissolved in water on the number of treatment cycles at: different angular speed of rotation of the rotor unit; different frequencies of flow pulsations; different flow shear rates. It is shown that the maximum concentration of dissolved oxygen is reached in 1–2 passes through the apparatus of the processed mixture. The thermophysical and energy characteristics of the operation of a rotary-type aeration-oxidation plant are determined depending on the frequency of flow pulsations. A comparative assessment of the heat-mass exchange and energy indicators of modern aeration devices used for wastewater treatment with the AORT installation has been carried out and it has been shown that when using the AORT installation, energy costs for aeration are reduced by 20 %.Документ Відкритий доступ Environmental problems caused by the use of reverse osmosis membrane elements, and ways to solve them(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Tyvonenko, A. V.; Mitchenko, T. Ye.; Vasilyuk, S. L.More than 70 percent of our planet is covered with water. And yet water is a scarce resource, and it is our future. According to the World Wildlife Fund, 1.1 billion people do not have access to it, and 2.7 billion experience a shortage of drinking water at least once a year. By 2025, two-thirds of the world's population may face water shortages. The shortage of drinking water and the search for renewable resources are of the most important problems in the modern world, the solution of which is directed to considerable intellectual and financial resources. Reverse osmosis is one of the most common technologies for obtaining highquality drinking water. Technological solutions constantly improve the process of reverse osmosis and reverse osmosis spiral wound membrane elements used, science and business go hand in hand. But the price of this progress is the annual generation of a large amount of waste generated from used reverse osmosis roll membrane elements, which are usually sent to the landfill, while there are no technological solutions for their disposal. This work provides information on the available amount of such waste in the world and the dynamics of its growth in order to assess the scale of environmental damage that occurs as a result. The work collected information about the market of reverse osmosis spiral wound membrane elements in the world, and directions of their use. The structure, composition of components and technical characteristics of reverse osmosis spiral wound membrane elements are considered in detail, which makes it possible to evaluate the ways and possibilities of their utilization. The problems of surface contamination due to various types of fouling are considered. The main attention in the work is given to the reasons that cause the formation of waste. Based on the collected data, the scale of annual waste generation, which is formed due to spent reverse osmosis roll membrane elements, was analyzed. The possibility of reusing reverse osmosis spiral wound membrane elements and the main methods of their safe disposal are also considered. Summarizing the work carried out, recommendations were made on ways to solve the problem.Документ Відкритий доступ Experimental scaling potential of heated water(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Kontsevoi, S. A.; Kontsevoi, A. L.; Khokhotva, O. P.The previously proposed mechanism of bicarbonate ions decomposition by the H-mechanism (with the formation of H+ and CO3 2-) or OH-mechanism (with the formation of OH- and CO2) is confirmed experimentally without and with heating water up to 190oC. The change decomposition mechanism depends on hardness, alkalinity and pH. The H-mechanism is observed at higher pH values (pH decreases) and the OH-mechanism is observed at lower values (pH increases) in particular solutions. The developed technique is based on the measurement of changing the pH (рНt) of the solution (at a fixed temperature of 15 to 25oC) after heating it to a given temperature (ranging from 40 to 190oC) and maintaining this temperature for at least 30 minutes. A decrease in the pH of the water after heating (рНt>0) indicates the formation of carbonate ions and the need for additional water treatment to reduce the hardness, alkalinity or pH. The greater the рНt, the greater the concentration of carbonate ions formed in water. If рНt is zero then this temperature can be used as a water quality index. This temperature is 86.4oC for tap water in Kyiv (pH 7.4). Measurement of рН in water meeting standards for water in German heating supply systems (pH 9.06, Hardness 45 mol/dm3 - 5 times less than in Ukraine) shows that such water is not scale-safe (рН150=0.15). The proposed technique will be able to replace the Langelier index (up to 90oC) and the carbonate index (up to 190oC) under the condition of systematic processing of experimental data obtained for the water of different compositions on its basis. This method can be used in addition to the expensive experimental method of dynamic tube blocking.Документ Відкритий доступ Integral methods for control of complex processes in NPP cooling systems(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Korsun, D.; Chichenin, V.; Zaitsev, S.; Kyshnevskiy, V.The relevance of the study is to ensure the reliable operation of NPP recirculating cooling water systems (RCWS) and select the method for discharge water conditioning. The purpose of the study is to provide scientific and technical substantiation of conditions that will effectively provide and improve the reliable and efficient long-term operation of NPP RCWS equipment. The study included analysis of main factors that influence the efficient and reliable performance of heat exchangers, and of modern scientific and technical approaches to study water-chemical regimes (WCR) of operating RCWS systems for preventing depositions of sparingly soluble salts and corrosion of power equipment, to study thermal-hydraulic regimes (THR) in RCWS WCR laboratory simulation, and to study the deposition rates on heat exchange surfaces (HES). The improvements refer to gas chromatography technique to control the content of oil product in water; the process flow diagram for the floor drain radioactive water treatment; methods of discrete control over RCWS operational efficiency with monitoring THR and WCR indicators, and deposition rates during laboratory studies and industrial tests. The obtained results make it possible to carry out a scientific and technical substantiation of the conditions for effective implementation of RCWS structural reconfigurations in order to increase the installed capacity factor (ICF) and for economical use of water during the variable loads on individual power units of large power facilities, considering their installed capacity, service life, and heat exchange equipment condition due to the use of separate RCWS with individual THR, WCR, and established individual standards for the amount of blowdown water and its possible reuse as makeup water for power units.Документ Відкритий доступ Intensification of the absorption of oxygen by water using a rotor-pulsating apparatus(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Sablii, L.; Obodovych, O.; Sydorenko, V.One of the important components of the quality of food products is the quality of water used. A common way to remove unwanted impurities from water is aeration, i.e. the oxidation of chemical compounds in water by oxygen. Aeration devices with mechanical energy input in comparison with other groups of devices, namely with energy input with gas phase and with liquid phase, have low power consumption and additional mixing of the processed medium. The work presents a study of oxygen absorption in water in an experimental setup with rotor-pulsating apparatus for water treatment in beverage production technology. In this paper, the energy and technological parameters of aeration of a model aqueous solution of a certain concentration of sodium sulfide in an experimental setup with a rotor-pulsating apparatus as an aerator are determined. The experimental aeration setup allows conducting research in several modes and consists in particular of a vessel, a rotor-pulsating apparatus, two ejectors - one at the entrance to the rotor-pulsating, the other at the outlet, the recirculation pipeline. Air from the atmosphere enters each of the ejectors through a separate air duct. The aeration of the studied water took place in the recirculation mode for 20 minutes. Determination of the oxygen mass transfer rate is determined by the iodometric titration method on the rate of oxidation of sodium sulfite. Experiments were conducted without using a catalyst. It is determined that when placing the ejector unit at the rotorpulsating apparatus inlet at the angular rotor unit velocity of 240.02; 270.18, and 300.02 s-1, the oxygen mass transfer rate is 1.39; 1.49 and 1.73 kg m3 /h. At the location of the ejector unit at the outlet of the rotor-pulsating apparatus, the velocity of the oxygen mass transfer under the same conditions is 1.17; 1.36 and 1.63 kg m3 /h respectively. However, the power consumption of the second scheme exceeds the power consumption by the first scheme by 50%.Документ Відкритий доступ Investigation of natural flocculants for use in wastewater purification processes(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Solodovnik, T. V.; Yakymenko, I. K.Contaminated industrial wastewater significantly reduces the volume of drinking water. A wide range of composition and insufficient treatment of wastewater from enterprises such as the textile, chemical or metalworking industries, which often fall into water bodies, negatively affect the state of aquatic ecosystems, and that is why it is necessary to carefully select the optimal treatment method. Among the types of wastewater treatment, the coagulation-flocculation process has gained considerable popularity, which occurs due to the adhesive and adsorption properties of coagulants and flocculants, which is widely used in the purification technologies of both natural and industrial wastewater from colloidal particles, radionuclides, phosphates, dyes and suspended particles. Coagulants are able to hydrolyze in water with the formation of various coagulation structures with high adsorption and adhesion properties, flocculants, in turn, contribute to the formation of flakes, sedimentation and filtration, stabilize the cleaning process, improve quality and increase the efficiency of equipment. During the experimental work, the employees of the Department of Chemical Technology and Water Treatment established the advantages of using natural flocculants in the process of wastewater treatment using colored model solutions as an example. A study was made of the influence on the degree of purification of such characteristics as the type of flocculant (for example, chitosan and sodium alginate) and coagulant (Al2(SO4)3-18H2O, ALS, PIX-318), the optimal dose of reagents, the type of dye (direct, active, dispersed) , settling time and content of residual ions. During the research, the Jar-test method was used, the essence of which is to simulate the process of floc formation, which is typical for industrial wastewater treatment plants. The study of the composition of model water samples was carried out using the spectrophotometric analysis method.Документ Відкритий доступ Microplastics in natural water: sources and determination(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Litynska, M.The paper is devoted for origin of microplastics in aquatic environment and possible methods of characterization and analysis. According to US National Oceanic and Atmospheric Administration, microplastics are synthetic organic polymer particles with a size less than 5 mm. Microplastics pollution is a significant ecological problem in the world. A lot of surface waters are significantly polluted by various types of microplastics. These pollutants were found in rivers, lakes, oceans, sediments, wastewater, drinking water and bottled water. But in Ukraine microplastic problem of surface water do not meet the interest of scientists and ecological organizations. Disintegration of plastic waste is one of the main sources of microplastics in water. But there are a lot of other sources of primary and secondary microplastics, including components personal care products, industrial abrasives, abrasion from car tires, paint failure, industrial processes, textile washing, atsea losses, etc. Microplastics can harm ecosystems and cause many health problems for different organisms, including problems with feeding and digestion, endocrine disruptions and changes in cellular functions. In general, health effects and environmental impacts are dependent on the size of the microplastic particles and chemical structure of these polymers. Thus, it is very important to understand chemical composition, physical forms, transport in environment and fragmentation of microplastics due to the need to predict possible exposure effects. There are a lot of methods for characterization and analysis of microplastics, but all of them have some disadvantages. Microplastics determination is often especially difficult for water with low microplastics content due to very large volumes of water samples and very small mass of separated plastics.Документ Відкритий доступ Pollution level of oil industrial water samples(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Gadirova, E.Organic toxic compounds such as polycyclic aromatic hydrocarbons, phenolic compounds are a global environmental concern as they cause inflammation and skin cancer. As you know there are two types of anthropogenic sources of hydrocarbons: petrogenic and pyrogenic sources. Petrogenic sources include crude oil and petroleum-derived hydrocarbon compounds. Pyrogenic sources of hydrocarbon compounds are formed as a result of incomplete combustion of organic substances such as oil, wood, coal. Before entering the open sea these oil products pass through the entire coastal zone. It is known that industrial waters are discharged into reservoirs after various chemical processes. The aim of this work was to determine how dangerous industrial oil water is when it enters the aquatic ecosystem. The article investigates the chemical composition of wastewater from the oil industry and identifies organic toxic compounds - polycyclic aromatic hydrocarbons and phenolic compounds. At the same time, the amount of heavy metals in water samples was analyzed. For chemical analysis, 3 samples were taken from the territory of the refinery. In total, 15 polycyclic aromatic hydrocarbons, 13 phenolic compounds and 9 heavy metals were analyzed in water samples. Water samples were analyzed in accordance with the contract HS-153/2-18 between Heydar Aliyev Oil Refinery and Baku State University's Department of Ecological Chemistry. The chemical analyses of heavy metals, polycyclic aromatic hydrocarbons and phenolic compounds were carried out using extremely sensitive devices such as Perkin Elmer ICP/OES-2100DV and GC-MSD gas chromatograph 6890N with a highly efficient mass-selective detector-Agilent 5975. In the Khazar Ecological Laboratory performed quantitative analysis of organic compounds in water samples as well as heavy metal determination.Документ Відкритий доступ Preparation of silver-containing natural zeolites with improved porous characteristics as sorbents for water purification(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Patrylak, L.; Nizhnik, B.; Yakovenko, A.; Melnychuk, O.; Pertko, O.The widespread application of Ukrainian natural zeolites in sorption and catalysis is limited by the shortcomings of their porous structure. Chemical modification of zeolites permits significant changes in their properties. The purpose of this work was to obtain silver-containing natural zeolites of the clinoptilolite type with improved porous characteristics by acid treatment and to study their antibacterial properties. Mild dealumination of the rock was carried out using ethylenediaminetetraacetic acid for 15 hours at 90 C, which significantly increased the specific surface area of the clinoptilolite sample to 90 m2 /g, and the volume of micropores to 0.037 cm3 /g, determined by low-temperature nitrogen adsorption/desorption. An establishment of a change in the chemical composition of the sample during processing by X-ray fluorescence analysis was made. Additional modification with silver in the amount of 1 wt % was carried out by impregnation with a solution of silver nitrate. The water of three lakes in Kyiv was studied for the total viable count by means of sowing in nutrient agar. The results were analyzed and a sample of water was selected to evaluate the effectiveness of the synthesized sorbent. The antibacterial properties of zeolite were confirmed with the worst of the water samples, the quality of which, in terms of the total viable count, was improved not only to the norms of surface water but also to the indicators for drinking water.Документ Відкритий доступ Production technology and filtering properties of carbon block cartridges(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Braslavska, Y.; Mitchenko, T.; Ponomarov, V.; Maletskyi, Z.; Kosogina, I.In the present paper, the information on the influence of various factors on the carbon block cartridges production technology and their potential impact on the properties of the finished product is presented. The possibilities of increasing the sorption-filtering efficiency of carbon block cartridges are presented. The technical and exploitation characteristics are influenced by the size of the mixture components granules, the physicochemical properties of active carbon and binder polymers, their ratio in the mixture, and the addition of bactericidal additives into the composition. The study of this topic is relevant, as evidenced by the analysis of the increasing number of publications on this matter over the past ten years. However, the production technology of carbon block cartridges is the know-how of manufacturing companies. This information is confirmed by the analysis of the technical characteristics of sixty carbon block cartridges from nine world manufacturers, whose products are WQA certified according to the NSF/ANSI 42 standard. The recommendations given by a number of authors on the size of activated carbon granules in the range from 40 to 120 mesh and polyethylene particles from 80 to 160 mesh with a flow rate of 1.4-3 g/10 min, can be taken as "reference points" in the development of extrusion mixtures with different components ratio. The following factors play an important role in obtaining effective cartridges: the quality of pre-extrusion mixing of the composition, its resistance to delamination during the “transition” from the mixer to the extruder loading zone, extrusion temperature regimes by zones, product cooling temperature, backpressure on the billet leaving the extruder. The information given in this article will be useful when producing new carbon block cartridges, improving the parameters of existing technologies, as well as in the research development of cartridges with new properties.Документ Відкритий доступ Synthesis of TIO2 by solvothermal method and its photocatalytic activity towards Biseptol and Congo red(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Aleksyk, A.; Yanushevska, O.; Dontsova, T.The creation of ceramic membranes with additional functional properties, such as antibacterial and photocatalytic, is a popular and promising area of research in the field of water treatment. The article is devoted to the synthesis of titanium (IV) oxide powders by the solvothermal method for their further usage as a photocatalytic selective layer in ceramic membranes. The study of the peculiarities of the photocatalytic materials synthesis for the creation of photocatalytic and at the same time antimicrobial ceramic membranes on their basis is extremely relevant, because it will allow to develop a method of synthesis of photocatalysts active to various pollutants. Therefore, the aim of the work was the synthesis of TiO2 powders by solvothermal method at different ratios of the starting reagents, the study of their physicochemical properties and the study of their photocatalytic properties in relation to different pollutant – antibiotics and dyes. The obtained powders were characterized by diffraction analysis, infrared spectroscopy, low-temperature nitrogen adsorptiondesorption and scanning electron microscopy. It is established that the ratio of the initial components significantly affects the final properties and characteristics of TiO2 powders. It was shown that the synthesis with a significant excess of the starting reagent (titanium isopropoxide) does not lead to the crystalline TiO2 sample, which was confirmed by diffraction analysis and infrared spectroscopy. The revealed porous structure of all TiO2 samples indicates a high specific surface area in them, which is also consistent with scanning electron microscopy studies. The highest photocatalytic activity is possessed by TiO2 samples, which are nanocomposites of anatase and rutile modifications. Such nanocomposites showed quite high activity towards antibiotics (Biseptol) and anionic dyes (Congo red).Документ Відкритий доступ The influence of the way of sewage sludge treatment on ammonium nitrogen content in the return wastewater flow(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Sorogovet, V. V.; Markevich, R. M.; Martsul’, V. N.; Sapon, E. G.; Lukashevich, S. O.Wastewater treatment facility receives, in addition to the influent, the return flow after sewage sludge treatment. Thus, the organic load on the facility increases as well as the nitrogen and phosphorus content load. There was studied the effect of different stages of sewage sludge treatment (sludge thickening, mechanical dewatering, storage on the grit bays and in the gathering ponds) on ammonium nitrogen content in the incoming flow. It is established that the most concentrated water by ammonium nitrogen is the return water from the gathering ponds, but the less concentrated is the supernatant water from sludge lagoons. Taking into account volume of the return flow the secondary ammonium nitrogen load from the every stage of sewage sludge treatment is calculated. It is revealed the seasonal and climatic impact on the gathering ponds return flow composition; it is shown that the biggest fluctuations occur in spring-summer period. The dependence of ammonium nitrogen content in the return flow on sludge thickening process time in the sludge lagoons is determined. The load contribution on the treatment facility by ammonium nitrogen in the return flow was 3% in the relation to this in the influent. The conclusion was made that with the existing technology of sewage sludge treatment the isolated scheme of return water treatment is not required. The comparative analysis on the effect of thermophilic and mesophilic conditions of anaerobic sewage sludge treatment on ammonium nitrogen content in the liquor was carried out. It was found that the higher ammonium nitrogen secondary load is created by the liquor of thermophilically treated sewage sludge: it is 16,4% versus 11,8% of mesophilically treated. Hence, the including of anaerobic sewage sludge treatment in the scheme significantly increases the load on treatment facility by ammonium nitrogen. In the conditions of cascade denitrification the distribution of incoming in the denitrification zones water flow is of great importance for providing required content of readily available organic substances. The change of ammonium nitrogen content in this flow will require the adjustment of its volume.Документ Відкритий доступ Water quality of small rivers in the Pripyat basin: environmental and fishery assessment(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2022) Grokhovska, Y.; Konontsev, S.The study of anthropogenic causes of the deterioration of the state of small rivers is the first step towards their conservation and restoration, improving the human environment as a whole. The aim of the study is the fishery and environmental assessment of water quality of small rivers in the Pripyat River basin (the area of right-bank tributaries in the middle part of the river) within the Rivne region in the northern-west region of Ukraine. The initial data for the assessment have been the results of monitoring (27 physical and chemical indicators) during 2010–2018. The assessment by the integral ecological index (Ie) has shown that the rivers belonged to the II quality class in terms of average values and were characterized as “clean” and “clean enough”. According to the worst values, the rivers belonged to the II-III quality classes and were characterized as “fairly clean” – “slightly polluted” – “moderately polluted”. The best water quality by the Ie index was established for the Zhabichi River within the urban-type settlement of Demydivka. Water quality of the Ustia River below the runoff of the cities of Rivne and Zdolbuniv has corresponded to IV-V classes i.e. was "dirty" and "very dirty" (high content of phosphates, nitrogen compounds, copper, manganese, and zinc). In terms of trophic state, the water of the rivers is mesotrophic (according to average values) and eutrophic (according to the worst values), except for the part of the Ustia River below the runoff of the city of Rivne, where the water is polytrophic. The rivers have failed to meet water quality standards for fishery water use by COD, BOD5, and heavy metals content (Cu, Mn, Fe, Zn).