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UDC 628.27
Shuvalov M. V., Sopyryaev M. N.
Analysis of City Sewerage Networks Operation
Summary
Results of the analysis of the data base on operation failures of sewerage networks of the city of Samara during the last 9 years of their operation are presented. From the point of view of reliability the gravity sewerage networks are the weakest element of the city wastewater disposal system. According to the statistical data the clogging is the cause of 99% of failures of functioning of the sewerage network. Most of the clogging (over 97%) happens at pipelines of up to 250 mm diameter. In the course of drawing up the schedules of planning-preventive works the operation departments should take into account the seasonality and pay particular attention to the sections of sewerage network with pipes of small diameter. During the reconstruction of gravity sewerage pipelines of less than 250 mm diameter it is recommended to use plastic pipes and pipes of larger diameter.
Key words
reliability , leak-proofness , sewerage network , clogging , damages
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DOI 10.35776/MNP.2019.12.06
UDC 628.27:69.059
Vasilyev V. M., Morozov G. V., Zhukov S. V.
Choosing the methods of rehabilitation of gravity sewers
Summary
Rehabilitation of sewer networks becomes an essential element in maintaining the entire sewage system in running order by minimizing the operating costs, increasing the life of pipelines, increasing the self-sustainability of the system using advanced automation, control and analysis tools. In order to maximize the life of pipelines and eliminate damaging parallel laid utility networks, it is necessary to correctly choose the methods of networks rehabilitation based on the experience and analysis of the existing ones. The main methods of repair and rehabilitation of pipelines are considered and classified. The necessity for system approach to the reconstruction is noted. A block diagram has been developed that provides for choosing a reconstruction method depending on the nature of the pipeline destruction and based on the telemetry inspection. Examples of its application in the existing structures are given. The article is written on the basis of an analysis of the technical publications and experience of operating and designing sewer networks in St. Petersburg.
Key words
sewerage network , soil failure , destruction and rehabilitation , trenchless method , gravity sewer , utility networks
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UDC 628.237
Fedorov Sviatoslav Viktorovich, Vasilyev V. M., Klementyev M. N.
Study of gas evolution in a sewer section
Summary
Transportation of wastewater through sewer networks is accompanied by the generation and evolution of gases from the flow. For a quantitative assessment of the gas evolution process a sewer section model has been developed in the ANSYS CFX finite element analysis package. The model takes into account the combined flow of wastewater, entrained air and sewage gas (e.g. carbon dioxide) coming from the collector tray. Monitoring was carried out in a section of the domestic sewage system (DN = 500 mm) in the industrial zone of Obukhovo in St. Petersburg. The measured values of the vacuum pressure are in the range of model calculations. The process of designing a computational area of the sewer section and establishing initial and boundary conditions is presented. As a result of modeling the dependences of the carbon dioxide concentration and the pressure of the gas-air environment in the underroof space of the pipeline with different slopes and filling levels were obtained. The results obtained can serve as a basis for the approach to predicting the process of gas evolution in sewer sections.
Key words
monitoring , simulation , ecological safety , sewerage network , carbon dioxide , hydrogen sulfide , methane , ammonia , gas evolution intensity
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DOI 10.35776/MNP.2019.12.07
UDC 628.218:624.139
Terekhov L. D., Mainy Sh.
Study of the changes in the thermal conditions of sewer networks in winter
Summary
Sewer pipelines are one of the main components of a sanitation system that determines its integrity and effectiveness. The sanitation system of Kyzyl has been constructed in the areas with a rigorous climate that is characterized by deep seasonal soil freezing exceeding 3.2 m. Reducing the depth of laying sewer pipelines against this background is a critical task. The study was aiming at the substantiation of reducing the pipe laying depth while maintaining the integrity of their operation in the normal way and ensuring non-freezing in possible emergency situations. The results of full-scale studies of the thermal conditions of operating the sanitation system of Kyzyl in winter are presented. The results of wastewater temperature measurements in different sewer network sections at different times of the day are given. Based on the obtained data a thermotechnical calculation of the network was carried out that provided for assigning 1.8 m pipe laying depth of the building drains with possible reduction in future.
Key words
sewerage network , wastewater , frost soil , pipe laying depth , thermal conditions , thermotechnical calculation
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UDC 628.23
Vasilyev V. M., Malkov A. V., Klementyev M. N.
Places of corrosive gas generation in the sewerage network
Summary
The factors that affect the generation of corrosive gases in the wastewater disposal system, saturation of the gas air environment with corrosive gases in sewers are considered. A number of structural components as well as hydraulic patterns of wastewater flow, its physical properties that enhance the gas generation processes are considered and described. The evaluation and prediction of the places of corrosive gas generation and emission provide for forecasting the measures focused on the reduction of the negative impact of emissions or their complete elimination. The operating services carry out regular sewer network monitoring with the purpose of detecting the places of emission generation. The future work of the services is limited to the isolation of corrosive gases by redistribution in the network, disposal into the atmosphere, neutralization or purification. The results of introducing the design of a pipe drop with a dead blanking in the lower part of the sewer shaft, ejector and pipe air vent are presented.
Key words
sewer , sewerage network , shaft , gas emission , corrosive gases , gas generation
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UDC 628.3:62-192
Alekseev M. I., Yermolin Yu. A.
method of sewer net segmentation and equivalenting
Summary
The design procedure of evaluating a most important index of the municipal sewer net reliability, i.e. relative amount of raw sewage spills resulting from the failure of separate sewer sections is suggested. The design procedure is using a typical characteristic of the system, i.e. its tree-type structure, and lies in the formal substitution of the sewer net for one dummy equivalent pipeline with the reliability parameters that are evaluated with the use of the known rates of failure and rehabilitation of the original (existing) sewer elements. The design procedure is simple and can be used directly by the companies that are operating municipal sewers.
reliability , failure , sewerage network , rehabilitation , state graph , raw sewage discharge amount
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UDC 628.21/.25
Vasilyev V. M., Malkov A. V., Verbitskii V. G.
Method of calculating gas volume and its travel direction in a sewer
Summary
In the process of operating deep sewers some problems arise such as corrosion of reinforced concrete structures of the sewerage network, saturation of the gas phase of the underground space with corrosive toxic substances, accidental emissions of these gases from the network into the atmosphere. Solving these problems is possible by arranging air exchange between the sewerage network and atmosphere. The available methods of calculating the amount of gas travelling in the sewerage network do not take into account the gas density, dynamic viscosity and other parameters that depend on the chemical composition of the gas phase. The lack of the recommendations does not allow estimating the network ventilation in relation to providing the required gas exchange rate. Consequently determining, estimating and substantiating the required capacity of the ventilation equipment are not possible. Possible flow redistribution is not considered either; and, hence, adjusting the gas exchange systems to the definite network parameters is not possible. A method of calculating gas amount and flow direction induced by fluid entraining capacity and natural draft with account of the physical and hydraulic parameters of wastewater and gas, network design features, daylight surface temperature is presented. The method provides for making calculations at the design stage with account of retrofitting ventilation units, filters and vent pipes. The following parameters are determined: the amount and direction of gas flow in the network, gas exchange rate, anticipated background concentration of corrosive gases at the preset gas exchange rate, network corrosion rate, overhaul period.
Key words
collector , sewerage network , calculation method , ventilation , gas exchange , corrosive toxic substances
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UDC 628.28
DOI 10.35776/VST.2023.04.04
Maslov Andrei
Reliable sealing cushions for big sewers
Summary
One of the most important measures for the successful repair works is the reliable blocking of the pipeline for the repair period. The use of LAMPE pneumatic sealing cushions for this purpose in large-diameter sewer networks has shown their high efficiency. LAMPE sealing cushions are fundamentally different from rubber plugs by the material they are made of and by the technologies of their manufacture. As a result, they are lighter, easily pass through a conventional hatch, do not require additional blocking, they are maintainable, and have an unlimited service life. All of these advantages make it possible to quickly and reliably cut off the failed section of the pipeline for the period of repair works and, having ensured their absolute safety, significantly reduce the time for eliminating the failure.
аварии.
Key words
pipeline , sewerage network , LAMPE pneumatic sealing cushion , LAMPE pneumatic lift
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UDC 504.3.054:628.316.7
Bogomolov M. V., Gavrilin A. M., Agevnin A. R., Kireyev Ju. P., Maleyeva A. V.
Field trials of wastewater air-gaseous emissions odor control technologies
Summary
The advanced technologies of removing nuisance odors from wastewater gaseous emissions are considered. The results of field trials of adsorption filters for the sewer vents and biological odor control systems for the manholes at Mosvodokanal MPUE facilities are described. For some years Mosvodokanal is developing optimal wastewater odor control methods. International experience is studied; investigations, experiments and pilot tests are carried out.
Key words
sewerage network , adsorption filter , biological odor control , hydrogen sulfide
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UDC 628.3:62-192
Alekseev M. I., Yermolin Yu. A.
On the specific character of wastewater system reliability indicators
Summary
Authors of technical literature related to various aspects of municipal wastewater disposal systems sometimes introduce notions and definitions that concede varying interpretations which is inaccurate, particularly when using mathematical tools. Therefore, the severity and definiteness of terminology under the circumstances are of special importance. The necessity, possibility and specific character of sewer reliability indicators are discussed. One of such indicators based on the hypothesis of the steady state of «failure-rehabilitation» processes is analyzed. The calculation of the introduced integrated municipal sewer reliability indicators essentially amounts to the estimation of the predictable volume of raw wastewater discharged from the system in some period because of the failure of some elements. One of the possible approaches to the solution of this problem in the context of the hypothesis of the steady origin of the sewer elements and facilities failure and rehabilitation flow is the method of segmentation and equivalenting. The ways of extending the suggested approach to an unsteady case when the failure flow rate shows seasonal periodicity or the network elements show tendency to «ageing» are designated.
Key words
sewerage network , reliability indicator , relative discharge volume , rate of failure , method of segmentation and equivalenting
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UDC 628.23
Vasilyev V. M., Malkov A. V., PANKOVA G. A., Klementyev M. N.
Detecting the places of corrosive gas emissions from sewers to the surface and conditions of their formation
Summary
Corrosive gas emissions from sewers to the surface happen because of the excess pressure increase in the underroof and shaft space of the sewer. The causes of the pressure increase in the shaft space are considered. The gas amount changing during entering the shaft and removed from it depends on the wastewater flow rate, sewer filling (the height of the gas flow), hydraulic gradient of the sewer, formation of stagnation zones (sludge sedimentation), and temperature. Variation of these parameters and thus the location of corrosive gas emissions to the surface depend on a number of factors that can be divided into several groups: construction, hydraulic, geodesic, operation, random, climatic. Reducing the gas emissions from sewers is possible by: introduction of construction solutions for gaseous medium redistribution; elimination of air blocks, installation of purification filters; avoiding deviations from the design solutions arising during the construction of deep sewers; proper management of wastewater flow at elevation differences; improvement of the sewer operation rules, severization of the requirements to the operating personnel qualification.
Key words
collector , sewerage network , joint movement of liquid and gas , gas emission , excess pressure , ventilation
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UDC 628.32.62-192.004.1
Bogomolov M. V., Dudchenko T. O., Pakhomov A. N., Streltsov S. A., Khamidov M. G., Belov N. A.
Improvement of Operational Reliability of Wastewater Disposal System of Moscow
Summary
The reliable and efficient operation of the wastewater disposal system of Moscow is one of the most important components of sanitary and ecological well-being of the city. Under the conditions of water saving and an annual reduction in volumes of water consumption and wastewater disposal the priority directions of development of the wastewater disposal system are improvement of water treatment quality and reliability of networks and facilities operation. With that end in view the Moscow State Unitary Enterprise Mosvodokanal (MSUE) introduces new methods of renovation of sewerage networks using widely up-to-date computer technologies and geoinformation systems, carries out the reconstruction of water treatment facilities. This complex of measures makes it possible to reduce considerably the risk of emergency situations.
Key words
treatment facilities , sewerage system , sewerage network , trenchless method of repair , pressure pipeline , geoinformation system , mini-TPP (mini-thermal power plant)
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DOI 10.35776/MNP.2020.03.09
UDC 628.24
Shuvalov M. V., Tarakanov D. I.
The use of pipes made of various materials for the construction of sewer networks
Summary
The results of the analysis of data on sewer networks in settlements of Russia as of 2014–2019 are presented. All settlements are divided into six groups depending on the number of inhabitants. For each group, the distribution of sewer networks is established depending on the material of the pipes. Сeramic and cast iron pipes have been most widely used over the past 100 years. Schedules for commissioning sewer networks made of various materials over the years have been developed. Over the past 20 years plastic pipes have gained widespread use accounting for about 50% of newly constructed sewer networks. Information was collected on the commissioning dates of individual sections of sewer networks. The largest number of the operating sewer networks was built between 1970 and 1979. In general, the standard service life for 55% of networks was exceeded in all settlements. In the coming years, a significant increase is expected in the share of plastic pipes in the total length of sewer networks.
Key words
sewerage network , pipe material , hydraulic characteristic , network length , standard service life
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UDC 628.21/.23:696.133.2
Vasilyev V. M., Malkov A. V., Klementyev M. N.
Example of air exchange arrangement and its calculation
for a sewerage network section under design
Summary
The method of calculating the volume and direction of gas travel in the sewerage network induced by the fluid carrying capacity and natural draft with account of different physical, hydraulic parameters of wastewater and gas, network design values, daylight surface temperature is presented. The method provides for making calculations at the design stage and determining the following parameters: the volume and direction of gas travel in the network, gas exchange rate, network corrosion rate, expected background concentration of corrosive gases at the assigned gas exchange rate, network corrosion rate, overhaul period. Herewith commissioning ventilation installations, filters and vent pipes is taken into account. To obtain the regularities for calculating and designing air exchange facilities in the operating urban tunnel sewers numerous experimental studies were carried out. Herewith the basic calculation formulas of the joint travel of fluid and air were obtained and the calculation method of determining the basic parameters of air exchange systems was developed. This method was used in the process of designing the Ufa wastewater disposal system expansion. The conducted economic comparison takes into account the basic technical and economic parameters of the ventilation system operating parameters; provides for assessing approximately different ventilation options and carrying out their comparison and calculating the economic effect.
Key words
collector , sewerage network , ventilation , gas exchange , air exchange calculation method
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UDC 628.21:62-192
GALPERIN E. M.
Ways of improving the integrity of wastewater network
Summary
The analysis of the main wastewater network failures is given. The data from foreign literature on blockage frequency depending on the pipe diameter is presented; for the classification of pipes by blockage risk level an index, i. e. generalized risk factor is suggested. The index stating the annual number of blockages per 1 km of a sewer of a certain diameter is more acceptable. Periodic maintenance, running or capital repair is a necessary requirement of the operation of any facility. Draining the pipe section under repair is a crucial stage from the point of view of the network integrity. It is suggested instead of one big sewer to lay two parallel sewers with total throughput capacity equal to that of the replaced one. The use of reinforced concrete pipes made of cement fondu characterized by the high corrosion resistance, long lifetime and abrasion resistance is considered. Savings from operation of reinforced concrete sewers made of cement fondu can compensate for its high cost. Polyvinylchloride is a perspective material for sewer production. The attention is drawn to the need of improving standards and regulatory documents related to the sewer maintenance.
Key words
reliability , pipeline , sewerage network , polyvinylchloride , generalized risk factor
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UDC 628.21:661.9
Kofman V. Ya.
Hydrogen sulfide and methane in the sewer networks (review)
Summary
International experience of using methods of protecting from hydrogen sulfide and methane generation in sewer networks is presented. The efficiency of using reagent methods and their cost depend to a great extent on the parameters of sewer pipelines and wastewater composition. Therefore in order to make a reliable choice of one or another method one should take into consideration the local conditions and carry out relevant tests.
Key words
sewerage network , hydrogen sulfide , methane , reagent method , injection
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DOI 10.35776/VST.2021.04.07
UDC 628.3:62-192
Yermolin Yu. A., Baranov L. A.
Specificity and methodological features of evaluating the reliability of sewer networks in large cities
Summary
The paper draws attention to the structural differences of two equivalent subsystems of a single infrastructure of a water supply and wastewater disposal system in a large city: a water supply subsystem and a wastewater disposal subsystem. It is stated that by now there is no unified established concept regarding the quantitative measure of the reliability of the sewer network. Based on the results of a review of modern domestic scientific and technical literature, three approaches to evaluating the reliability of municipal wastewater disposal systems are singled out and critically analyzed. The capabilities determined by the accepted assumptions are identified, and the areas of practical use of each of them are specified.
Key words
reliability , sewerage network , state graph , method of segmentation and equivalenting , Kolmogorov equations , «destruction and replication» scheme
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DOI 10.35776/VST.2022.06.04
UDC 628.2:62-192
Yermolin Yu. A.
Sewer network reliability control
Summary
The fundamental possibility of the sewer network reliability control by developing (with subsequent implementation) mid- and long-term plans for its renovation according to the criterion of the minimum possible environmental risk is discussed. As a quantitative measure, an indicator of the operational reliability of the network is considered, i.e., the relative volume of wastewater not delivered to the treatment facilities because of the failures of the network structural elements. The assumptions and limitations of such control attributable to the specific features of the object, are discussed. An algorithm for developing a network renovation plan according to the environmental criterion is proposed using the method of object segmentation and equivalenting.
Key words
reliability , management , sewerage network , method of segmentation and equivalenting , environmental risk
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УДК 621.644.075.004.6
Kuznetsov V. N., Tutubalina M. V.
Economic methods of network renovation under the conditions of a megacity
Summary
Searching for the methods of rehabilitation of utility networks has become a top priority task for «Vodokanal» MUE in the process of planning the operational program of replacing the old pipelines and carrying out repair works. After the comprehensive analysis of the cost of replacing water pipelines and sewers in the cluttered urban environments it was decided to introduce innovations that could provide for the network renovation with minimum expenses for improvements. The arguments are put forward in favor of the use of trenchless technologies of water and sewage pipelines rehabilitation in the city of Ekaterinburg. During the tests of the technologies their advantages and disadvantages were revealed. The conditions of the economic viability of using trenchless technologies are recommended.
Key words
siphon , water supply network , sewer , sewerage network , polymer liner , trenchless renovation of pipelines
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