Method of evaluating the amount of emergency wastewater discharges into the environment

Summary

The method of evaluating the amounts of emergency discharges of wastewater into the environment caused by the overrun of wastewater inflow over the capacity of the sewage pumping stations resulted from the emergency shutdown of pumps or inflow of off-nominal wastewater flow is presented. The results of studying failure and restoration flows of the pumping equipment in the combined sewers are presented together with the algorithms of reliability assessment by analytical method and Monte-Carlo simulation method. The use of the developed method of evaluating the amounts of emergency discharges of wastewater into the environment provides for substantiating the solutions at the stage of project documentation development that meet the requirements of the legislative and regulatory documents in the field of water supply, wastewater disposal and environmental protection. The indicators of reliability and environmental safety (probability of flooding of the sewers transporting wastewater to the pumping stations when wastewater is discharged into the environment) variate not only depending on the failure-free performance and maintainability indicators but also depending on the state of the sewage pumping station during the initial period of operation. For this reason one of the ways of improving these indicators at sewage pumping stations is timely execution capital and regular repairs of pumps.

Key words

wastewater , sewerage pumping station , reliability indices , parameters of failure flows , analytical method of reliability assessment , simulation method , density function

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UDC 628.21.62-192

GALPERIN E. M., Strelkov A. K.

The reliability of municipal sewers

Summary

The aspects of the reliability of municipal sewers are considered. The reliable transportation of raw wastewater to the treatment facilities is extremely important for the normal town-living. At present there is no authorized quantitative index of sewer reliability. Municipal sewer is a comprehensive technical system and the reliability indices shall be designated as appropriate. The use of the mathematical model of such facilities provides for determining the complex of the sewer reliability indices. The factors that affect the sewer reliability are analyzed; specific measures of its improvement are suggested.

Key words

Failure , collector , mathematical model , clogging , reliability indices , sewer

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UDC 628.1/.3.196

GALPERIN E. M., Strelkov A. K.

On the reliability of water supply and wastewater collection systems

Summary

Integrity of operation is the most important attribute of the water distribution and wastewater collection networks. However up to now the regulatory documents lack the definition of this notion. By the case studies of the water distribution network operation the great losses that the national economy incurs due to the lack of the integrity indicators in the construction rules and regulations have been demonstrated. It is noted that introducing these indicators will provide for the significant improvements in the design methods and evaluation of the operation of water and wastewater systems. A considerable number of the experts are not ready to change the conventional working arrangements ignoring the Order of the RF Ministry of Regional Development that offers the indicators that take into account the reliability of operation. The RF Ministry of Housing and Public Utilities must display insistence and perseverance in adopting a firm technical policy in relation to this issue.

Key words

efficiency , reliability indices , integrity of operation , regulatory documents , terms and definitions , regeneration processes in wastewater disposal , redundancy types

DOI 10.35776/VST.2021.10.01
UDC 628.2:62-192

Stepanov Mikhail, Primin Oleg

Problems of the reliability of water supply and wastewater disposal systems, and ways of solution

Summary

Reliability and environmental safety are the main requirements for water supply and wastewater disposal systems. Pipeline systems are an integral part of the infrastructure of modern cities. Malfunctions of these systems are mainly associated with failures in pipeline sections, that are the most functionally significant, expensive and vulnerable elements of the systems. The increasing rates of wear and unsatisfactory technical condition of a significant number of water pipelines and sewers in most cities and communities of Russia, the limited material resources for their rehabilitation and renovation in the context of reforming the housing services and public utilities of Russia require a scientifically based approach to solving the problem of assessing and ensuring their reliability. It is noted that up to now, in domestic practice, the accumulation and use of statistics for determining the reliability indicators of the elements of water supply and wastewater disposal systems, as well as planning their rehabilitation, have been arranged unsatisfactorily. Methods for assessing the reliability of pipelines, a methodology for planning their rehabilitation using a software application, criteria for selecting objects for pipeline renovation and ways to improve their reliability are presented.

Key words

pipeline , ecological safety , reliability indices , methodology for rehabilitation planning

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UDC 628.152

GALPERIN E. M., Bukhman N. S.

Calculation of loop network reliability

Summary

The reliability of loop water distribution network operation has been its primary property. However, until now the regulatory documents for designing water distribution networks lack the reliability indices. There is no consensus among the experts related to these indices. Earlier proposed set of reliability indices of a loop water network is considered and one of the possible methods of their calculation is suggested. The data on the time of the water mains 325.78 km long operating in serviceable and unserviceable conditions is set by the example of the Samara municipal water network (the data for 2014). For the theoretical determination of the time of the water mains being in serviceable and unserviceable conditions Markovian model was used with discrete states and continuous time. To decrease the dimensionality of the current task all the states with equal number of isolated sections were curtailed into one state (subset). The feasibility of this solution was prompted by the practice of water network operation. The model verification by Pearson’s Chi-square criterion allows accepting the hypothesis of the theoretical results corresponding to the available experimental data.

Key words

hydraulic design , reliability indices , loop water distribution network , Chi-square (Pearson’s) , Markovian model with discrete states and continuous time

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UDC 628.292.65.011.4

Ignatchik S. Iu.

Energy conservation and reliability assurance in upgrading sewage pumping stations

Summary

The main principles of reliability and energy conservation calculation method for designing the upgrade of local sewage pumping stations that are transferring wastewater to the treatment facilities are presented. When preparing a feasibility study of the project design the technology and probability indices of reliability for each element of the process part of the pumping station together with probabilistic and individual dimension reliability are determined. The option of upgrading the process part is selected with account of the environmental requirements and investment efficiency of the project.

Key words

wastewater , power saving , operation expenditures , pumping station , calculated hydraulic model , net discounted expense , reliability indices

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