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Number 10 / 2025
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UDC 628.16.067.3
DOI 10.35776/VST.2025.10.01
Strelkov Aleksandr, Gridneva Marina, Dremina Eleonora
Specific features of washing high-porous filter media
Summary
The results of studying the process parameters of high-porous water filter media changing during operation, as well as the effect on the filter cycle, the time of protective action of the media, and the time to reach the maximum head loss are presented. The efficiency of design solutions for slotted drainage and distribution devices is discussed. Recommendations are given for adjusting the particle size distribution and the height of the media layer during operation to ensure the optimal filter performance.
Key words
filtering material , physical integrity , backwash rate , porosity , drainage and distribution device , slotted coating , filtration parameters
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UDC 628.144
DOI 10.35776/VST.2025.10.02
Strelkov Aleksandr, Teplykh Svetlana, Gorshkalev Pavel, Erofeev Vladimir
Estimation of the calculation parameters of the water distribution network reliability with account of submain pipelines
Summary
The operational reliability of water distribution networks and a water supply system as a whole is a key challenge the engineering and operating companies are facing. Inadequate attention is paid to calculating the operational reliability parameters of loop water distribution networks at the design stage, notwithstanding the fact that the network being the largest and most expensive element of the water supply system (in big communities) compared to other parts of the system. Different options for calculating the reliability parameters of loop water distribution networks using the classical method – accounting only for significant pipelines and all elements of the water distribution network, such as submain pipelines, etc. are considered. The calculation results show that while considering all the pipelines in the calculations, the network operating time in emergency operation is reduced, whereas the network operating time in the ordinary course (except the customers connected directly to the pipe section being cut off for repairs) increases.
Key words
water supply network , hydraulic design , free pressure , network operation parameters , water distribution network reliability , reliability calculation methods , network failures
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UDC 628.35
DOI 10.35776/VST.2025.10.03
Strelkov Aleksandr, Stepanov Sergei, Andreev Sergei, Zolotukhin Aleksei
Study of the aeration intensity effect in a bioreactor on the pressure head
Summary
The design of a bioreactor with vertically arranged anoxic and aerobic zones is described. The bioreactor is designed for wastewater biological treatment at the facilities ranging from ultra-small to low-capacity ones. It is shown that the given bioreactor type is characterized by the ease of operation owing to the lack of circulation pumps and mixers. The pressure head dependence on the aeration intensity and gas filling coefficient in the aerobic zone of the bioreactor is presented. It has been established that the gas filling coefficient in the aerobic zone of a bioreactor operating under static conditions eliminating liquid overflow into the anoxic zone can be calculated as the ratio of the aeration intensity to the average air bubble rise rate. It has been determined that air bubbles generated in industrial pneumatic fine-bubble aerators rise in a turbulent mode at a rate proportional to the bubble diameter raised to the power of minus 0.4. The results obtained in this investigation will be used in the second part of the experimental and theoretical studies that will provide for determining the dependence of the circulation flow rate on the aeration parameters, and developing a mathematical model of the fluid flow in a bioreactor with the vertical arrangement of aerobic and anoxic zones.
Key words
wastewater , biological treatment , aeration , bioreactor , anoxic zone , aerobic zone , gas filling coefficient
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UDC 628.35
DOI 10.35776/VST.2025.10.04
Strelkov Aleksandr, Stepanov Sergei, Teplykh Svetlana, Utkin Aleksei
Study of the acidification technology at the municipal wastewater treatment facilities in Dimitrovgrad
Summary
The results of the laboratory studies of the raw sludge acidification technology at the municipal wastewater treatment facilities in Dimitrovgrad are presented. The following parameters were determined: the specific formation of VFA (based on acetate ion) was 62–71 mg/g of ash-free matter, and the rate of VFA formation (based on acetate ion) was 1.07–1.33 mg/(g·h) of ash-free matter. A rough estimate of the acidification potential of raw sludge is given: 32–33 mg of CODVFA/mg of sludge dry matter assessed as average in magnitude. An analysis of the composition of wastewater in the city of Dimitrovgrad for 2021–2024 showed that the organic matter concentration in primary effluent is sufficient for the denitrification process; however, insufficient for the implementation of biological phosphorus removal technologies. The obtained results confirmed the feasibility of using acidification as part of the scheduled upgrade of the municipal wastewater treatment facilities in Dimitrovgrad.
Key words
wastewater treatment , acidification , chemical phosphorus removal , biological phosphorus removal , volatile fatty acids
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UDC 628.2:681.5.017
DOI 10.35776/VST.2025.10.05
Shtepa Vladimir, Stepanov Sergei, Avdeenkov Pavel, Dubina Aleksandr
Substantiation of monitoring a wastewater disposal system and technological risk estimation
Summary
Based on the system analysis a technological complex for the municipal wastewater transportation and treatment was examined in terms of using facility-based monitoring at the water and wastewater utilities. The given complex is specified as a distributed system. Low observability of wastewater transport processes was identified, characterizing the wastewater disposal system as a poorly-governed facility. Following physical modeling average values for a range of municipal wastewater quality indicators were simulated under various discharge conditions for residential customers, a dairy, and a cotton mill. The operation of municipal wastewater treatment facilities was simulated using POTENTSIAL software. It was shown that, over a fairly wide range of variations in the flow rate and composition of industrial wastewater in terms of organic matter, ammonium, and phosphate concentration, no critical impact on the treatment level was revealed, while a sharp change in pH of the raw wastewater could disturb the biological treatment process. Based on a predictive approach, a valid scheme and control sequence for the wastewater disposal system as a single technological complex was proposed, that reduces significantly the risk of man-caused emergency situations.
Key words
biological treatment , monitoring , water disposal , municipal wastewater , physical and mathematical simulation , technological risks
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UDC 628.32
DOI 10.35776/VST.2025.10.06
Kichigin Viktor, Iudin Aleksandr
Studying the technology of wastewater sludge chemical dewatering with the help of experimental-statistical models
Summary
The results of experimental studies of the specific resistance of raw wastewater sludge changing under the effect of six types of coagulants and a polyacrylamide flocculant at doses ranging from 0 to 5.25 g/kg dry matter are presented. The effect of each chemical on the raw sludge dewatering rate is determined. Mathematical models are obtained for the dependence of changes in sludge specific resistance on the coagulant and flocculant amount added. The mathematical models are presented both as implicit and explicit equations, and as explicit isolines. It is proven that more expedient is using polyoxyaluminum sulfate and aluminum sulfate coagulants at a dose of up to 5.25 g/kg dry matter and a polyacrylamide flocculant at a dose of 5.25 g/kg dry matter which provide for maximum reducing the raw sludge specific resistance.
Key words
primary settler , optimal dose of chemicals , sludge specific resistance , сырой осадок сточных вод , mathematical and graphical models of sludge water yielding capacity
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UDC 628.381.1
DOI 10.35776/VST.2025.10.07
Strelkov Aleksandr, Teplykh Svetlana, Teplykh Evgenii, Davidenko Anna
Study of using domestic wastewater sludge as a multifunctional additive in the process of ceramic brick production
Summary
While using wastewater sludge as an additive in the production of ceramic bricks, the precise moisture content of the sludge must be taken into account, since it affects the burning time at the required temperature. Based on analyses and published literature data, the following types were chosen for the follow-up studies of using sludge as a multifunctional additive in ceramic bricks: mature sludge from sludge beds; mature sludge from sludge beds with the addition of a mixture of raw sludge and excess activated sludge (50:50 ratio) from the Samara municipal wastewater treatment facilities. The experiment was based on theoretical assumptions and hypotheses. Furnace charge from the Samara Ceramic Material Plant using standard ceramic brick production technology, was taken as a basis. The experiment involved replacing ash and some of the coal clay with the waste in question – domestic wastewater sludge. Based on this sludge, the composition was developed and the process parameters for producing porous aluminosilicate filler were determined. The obtained filler with a fine-porous structure and a density of 400–700 kg/m3 is comparable in properties to expanded clay gravel. This filler is recommended as a coarse aggregate in the composition of foamed concrete.
Key words
activated sludge , wastewater sludges , sludge utilization , solid part of sludge , composition of sludge dry matter , production of ceramic materials , multifunctional additives
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