Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study
Design and management of combined sewer overflows (CSOs) have been, so far, mainly based only on complying a fixed dilution rate of wastewater in stormwater during rain events. This poses serious environmental issues, since the definition of the acceptable dilution does not consider the characterist...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Environmental Sciences Proceedings |
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| Online Access: | https://www.mdpi.com/2673-4931/21/1/8 |
| _version_ | 1827726177564884992 |
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| author | Alessandro Farina Armando Di Nardo Rudy Gargano Roberto Greco |
| author_facet | Alessandro Farina Armando Di Nardo Rudy Gargano Roberto Greco |
| author_sort | Alessandro Farina |
| collection | DOAJ |
| description | Design and management of combined sewer overflows (CSOs) have been, so far, mainly based only on complying a fixed dilution rate of wastewater in stormwater during rain events. This poses serious environmental issues, since the definition of the acceptable dilution does not consider the characteristics of the upstream urban catchment, nor the climatic features, nor those of the receiving water body. Overflows are usually designed for activation when the mixed discharge reaches about five-times the mean wastewater discharge (though it may vary, depending on country regulations), the latter being the mean dry weather wastewater discharge. Accordingly, recent regulations started enforcing limits also on the frequency of overflows. Overflow activation frequency and discharged volumes of pollutants may depend on the upstream catchment features as well as on the precipitation regime. The great variability in these factors could make the impact on the receiving water body of similarly designed overflows quite different. In this study, the behavior of a CSO placed at the outlet of urban catchments with the same size but different characteristics was simulated with SWMM. The considered hydrological parameters were catchment imperviousness, width and slope, Manning coefficient and depression storage. Served population characteristics affecting the combined sewer hydraulic regime were studied by changing the population density and the mean wastewater discharge per capita. After defining realistic ranges for each parameter, the time series of discharged overflows were calculated for all the combinations of the variable catchment parameters, corresponding to 20-year-long precipitation series from a single rain gauge. The obtained results, although preliminary, indicate that CSOs’ impact on the receiving water body strongly depends on the characteristics of the upstream urban catchment. Therefore, such characteristics should be considered in CSO design and management. |
| first_indexed | 2024-03-10T22:47:29Z |
| format | Article |
| id | doaj.art-9db825aceeef4c2faa468927921e3c6e |
| institution | Directory Open Access Journal |
| issn | 2673-4931 |
| language | English |
| last_indexed | 2024-03-10T22:47:29Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Environmental Sciences Proceedings |
| spelling | doaj.art-9db825aceeef4c2faa468927921e3c6e2023-11-19T10:36:55ZengMDPI AGEnvironmental Sciences Proceedings2673-49312022-10-01211810.3390/environsciproc2022021008Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric StudyAlessandro Farina0Armando Di Nardo1Rudy Gargano2Roberto Greco3Department of Engineering, University Luigi Vanvitelli, 81031 Aversa, ItalyDepartment of Engineering, University Luigi Vanvitelli, 81031 Aversa, ItalyDepartment of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, ItalyDepartment of Engineering, University Luigi Vanvitelli, 81031 Aversa, ItalyDesign and management of combined sewer overflows (CSOs) have been, so far, mainly based only on complying a fixed dilution rate of wastewater in stormwater during rain events. This poses serious environmental issues, since the definition of the acceptable dilution does not consider the characteristics of the upstream urban catchment, nor the climatic features, nor those of the receiving water body. Overflows are usually designed for activation when the mixed discharge reaches about five-times the mean wastewater discharge (though it may vary, depending on country regulations), the latter being the mean dry weather wastewater discharge. Accordingly, recent regulations started enforcing limits also on the frequency of overflows. Overflow activation frequency and discharged volumes of pollutants may depend on the upstream catchment features as well as on the precipitation regime. The great variability in these factors could make the impact on the receiving water body of similarly designed overflows quite different. In this study, the behavior of a CSO placed at the outlet of urban catchments with the same size but different characteristics was simulated with SWMM. The considered hydrological parameters were catchment imperviousness, width and slope, Manning coefficient and depression storage. Served population characteristics affecting the combined sewer hydraulic regime were studied by changing the population density and the mean wastewater discharge per capita. After defining realistic ranges for each parameter, the time series of discharged overflows were calculated for all the combinations of the variable catchment parameters, corresponding to 20-year-long precipitation series from a single rain gauge. The obtained results, although preliminary, indicate that CSOs’ impact on the receiving water body strongly depends on the characteristics of the upstream urban catchment. Therefore, such characteristics should be considered in CSO design and management.https://www.mdpi.com/2673-4931/21/1/8CSOSWMMurban hydrologywater qualityparametric analysis |
| spellingShingle | Alessandro Farina Armando Di Nardo Rudy Gargano Roberto Greco Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study Environmental Sciences Proceedings CSO SWMM urban hydrology water quality parametric analysis |
| title | Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study |
| title_full | Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study |
| title_fullStr | Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study |
| title_full_unstemmed | Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study |
| title_short | Assessing the Environmental Impact of Combined Sewer Overflows through a Parametric Study |
| title_sort | assessing the environmental impact of combined sewer overflows through a parametric study |
| topic | CSO SWMM urban hydrology water quality parametric analysis |
| url | https://www.mdpi.com/2673-4931/21/1/8 |
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