Introduction. In this paper, we analyze various methods of snow removal in urban areas and consider the most cost-effective and efficient solutions for snow removal and disposal using heat from sewage drains by means of stationary snow-melting points (SMP) in Nur-Sultan. In cooperation with Astana su Arnasy specialists, responsible for the operation of the city sewer system, as well as cleaning and disinfection of urban sewage drains, we reviewed the main advantages and disadvantages. Methods. The paper looks into the possibility of utilizing heat from sewage drains with the help of heat pumps. This method has been successfully tested at a sewage treatment plant and is currently used to heat auxiliary premises. The same principle can be applied in SMPs with a separate discharge of meltwater to the storm sewer. Results. Having studied the experience of using various methods for snow removal in urban areas, we find that snow removal with the use of sewage drains through the creation of special snow-melting complexes integrated with the city sewer system is the most promising method for Nur-Sultan since it allows for reducing costs, intensifying the process of snow melting, and eliminating the hazardous impact of meltwater on the environment. Conclusion. To ensure successful implementation and use of this snow removal method in Nur-Sultan, it is required to conduct a number of additional studies on the impact of sewage treatment plants on the technological processes, as well as to test options for separating sewage drains with the help of heat pumps, and, based on the studies conducted, to determine the final configuration of snow-melting complexes.
Introduction. Large urban agglomerations have to deal with issues related to the high-quality drinking water supply. These issues are mainly due to water quality deterioration, poor condition and severe wear of water supply infrastructure facilities. Materials and methods. In our study, we analyze the composition of drinking water in the water supply system of St. Petersburg for SiO2 and Al2O3 nanoparticles and organic substances, including soluble proteins, protein components, and salts. For this purpose, we estimated the concentration and distribution of nanoparticles and organic impurities in the sediment formed after water evaporation from a sample in the form of a droplet. During the process, the following methods were used: the method for dehydration of water droplets with the formation of a solid phase, the methods for optical analysis of the sediment structure based on image analysis and recognition (photo and video recording of microscopic images), mathematical modeling of sediment structures’ formation, and statistical analysis of the results. Results. The presence of impurities in water was determined by the formation of periodic annular ring structures in sediments of aqueous solutions. The analysis of the structures obtained made it possible to determine the composition of the mixture and percentage content of individual fractions by the type of structural elements and their periodicity. We also developed a mathematical model simulating the processes of particle settling out of a solution. The calculations were carried out using model liquids and made it possible to obtain dependencies for the distribution of various dissolved particles in the structure of the solid phase, as well as to describe the staged mechanism in settling during its formation.
Introduction. Separation chambers are designed and built for separate and partially separate sewerage systems. Their main function is to separate the flow of relatively clean water during heavy rain. This allows the discharge of such water without treatment into water bodies or storage tanks. The approach reduces the load of wastewater treatment plants. To design separation chambers, we need to understand how their design features affect the process of flow separation. It is possible to study the hydraulic characteristics of separation chambers of any design with the help of computer simulation. Two designs of separation chambers were investigated: a circular spillway with a full-scale prototype and a spiral spillway proposed by the authors. Methods. The research was based on simulation in the ANSYS CFX finite element analysis software. For each design, a series of five experiments with different incoming flow rates was performed. Results. Models of two types of separation chambers were developed and qualitatively evaluated. The hydraulic characteristics were established and quantified: the uniformity of the flow discharged for treatment and the spillway discharge coefficient. Conclusion. As a result, a principled approach was formed and tested. Using this approach, it is possible to study the hydraulic characteristics of separation chambers of various designs for their further use in the sewerage system.
Introduction. Water supply organizations are currently in need of innovative solutions and technologies based on the concept of the closed-loop resource cycle. The need for sustainable use of resources serves as the basis for changing the existing approach where worn-out resources are considered wastes. Materials and methods. In this paper, we show that it is expedient to restore the sorption properties of granulated activated carbon (GAC) by its reactivation and reuse in closed-loop recycling. We also present methods to study GAC properties and technology of reactivation. Results and discussion. Based on the results of the GAC samples’ analysis, it was found that, during reactivation, the mass content of each fraction changes with a strongly pronounced decrease in the content of large granules with a size of 1.18–2.00 mm and an increase in the content of small granules with a size of 0.60–1.00 mm. Besides, the apparent density of the sorption material changes and the volume of carbon that underwent two reactivations falls below 75%. Conclusion. GAC reactivation in dual-media rapid filters allows us to optimize not only the operating and financial expenses of the company but also those natural resources that would have been spent for the production of new carbon.
Introduction. In this paper, we consider the operation principle, features, advantages, and disadvantages of compact domestic wastewater treatment plants designed by domestic manufacturers. The compact plants used until 2000 were designed to reduce such two indicators in the waste liquid as BOD and suspended solids. Since 2000, modern compact plants capable of reducing four indicators (BOD, suspended solids, nitrogen, and phosphorus) have been developed and installed in Russia. Methods. Biological methods of removing organic substances and nitrogen from the waste liquid are used at modern compact plants. Phosphorus is removed by using both biological and physical-and-chemical methods. The main issue in the operation of compact domestic wastewater treatment plants is the extremely nonuniform flow of wastewater; the coefficient of hourly nonuniformity can be 3.5 or higher. Another serious issue is the reduction in the waste liquid temperature in the cold period to critical values that hinder the biochemical oxidation of organic substances in aeration tanks. In permafrost areas (Yakutia), the influence of this factor can be observed even in the warm period. Results. Based on theoretical research and many years of experience in commissioning, we identified the consequences of design flaws and violations during operation for the stability and performance efficiency of compact plants of various modifications. Conclusion. The performed study made it possible to develop and recommend the optimal option for wastewater treatment, which allowed us to ensure that the indicators were brought to the maximum permissible concentrations of pollutants (suspended solids — 2–3 mg/l, BODult — 3–5 mg/l, ammonium nitrogen — 0.4 mg/l, nitrate nitrogen — 9 mg/l, phosphorus — 0.2 mg/l), established for discharge into fishing reservoirs.
