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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Problems in sewer network operation and ways of their elimination

Summary

The main problems arising during the operation of sewer networks – blockages, network deterioration and odors are highlighted. The causes of their occurrence are considered and methods of their elimination are proposed. Under the conditions of Russia blockages are most likely to occur as a result of errors in design and erection. These are violation of the pipe turnout grade, pipe diameter mismatch, turnout grade fault because of soil movement, unsatisfactory state of sewer and pipeline failure. Design and erection errors and low cultural level of the users of the sewer system can lead to the emission of high concentrations of hydrogen sulfide. Any blockage in the sewerage system is accompanied by foul odor above ground that is explained by the emission of hydrogen sulfide. By using advanced computer aids it is possible to keep account of all the factors that affect the useful life of sewers. Systematization of the obtained data and its further use provide for extending the pipe life and reduce the expenditures for renovation and maintenance of sewers. The paper is written on the basis of designing and operating the sewer networks in Saint-Petersburg.

Key words

pipeline , odor , sewer , sewerage system , clogging , microbiologic corrosion , sewer network deterioration , soil failure