Quantification of sewer system infiltration using δ18O hydrograph separation

2009 ◽  
Vol 60 (3) ◽  
pp. 727-735 ◽  
Author(s):  
V. Prigiobbe ◽  
M. Giulianelli

The infiltration of parasitical water into two sewer systems in Rome (Italy) was quantified during a dry weather period. Infiltration was estimated using the hydrograph separation method with two water components and δ18O as a conservative tracer. The two water components were groundwater, the possible source of parasitical water within the sewer, and drinking water discharged into the sewer system. This method was applied at an urban catchment scale in order to test the effective water-tightness of two different sewer networks. The sampling strategy was based on an uncertainty analysis and the errors have been propagated using Monte Carlo random sampling. Our field applications showed that the method can be applied easily and quickly, but the error in the estimated infiltration rate can be up to 20%. The estimated infiltration into the recent sewer in Torraccia is 14% and can be considered negligible given the precision of the method, while the old sewer in Infernetto has an estimated infiltration of 50%.

1998 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Marie-Christine Gromaire-Mertz ◽  
Ghassan Chebbo ◽  
Mohamed Saad

An experimental urban catchment has been created in the centre of Paris, in order to obtain a description of the pollution of urban wet weather flows at different levels of the combined sewer system, and to estimate the contribution of runoff, waste water and sewer sediments to this pollution. Twenty-two rainfall events were studied from May to October 1996. Dry weather flow was monitored for one week. Roof, street and yard runoff, total flow at the catchment outlet and waste water were analysed for SS, VSS, COD and BOD5, on both total and dissolved fraction. Results show an evolution in the characteristics of wet weather flow from up to downstream: concentrations increase from the catchment entry to the outlet, as well as the proportion of particle-bound pollutants and the part of organic matter. A first evaluation of the different sources of pollution establishes that a major part of wet weather flow pollution originates from inside the combined sewer, probably through erosion of sewer sediments.


2011 ◽  
Vol 63 (11) ◽  
pp. 2590-2597 ◽  
Author(s):  
M. C. Gromaire ◽  
P. Robert-Sainte ◽  
A. Bressy ◽  
M. Saad ◽  
B. De Gouvello ◽  
...  

Many studies have shown that roofing materials are an important source of metals in urban runoff. Today, in the context of the European Water Directive (2000/60 CE), the quantification of these emissions is necessary, and thus the development of assessment tools is needed. This study focuses on a small urban catchment (drained by a separative sewer system). Atmospheric fallout, road runoff, roof runoff and total runoff at the outlet of the catchment were sampled. The aim is (1) to verify the contribution of roofing materials to metallic flows of Zn and Pb at the catchment scale and (2) to try to model emissions using some models previously developed at the test-bed scale. These models have to be tested at different spatial scales. Results obtained confirm the strong contribution of roofing materials to Zn and Pb flows at the catchment scale. For Zn, models tested were successfully transposed and validated at the roof and the catchment scales, permitting a good quantification of Zn emissions. For Pb, the use of the models highlights some difficulties, especially concerning the identification and the quantification of lead surface areas implemented.


Author(s):  
Qi Zhang ◽  
Weiyun Shao ◽  
David Z. Zhu ◽  
Weilin Xu

Abstract Modelling air movement in sewer networks is needed in order to address the issues related to sewer odour complaints and sewer corrosions due to hydrogen sulphide in sewers. Most of the existing air flow models can only be applied in small sewer networks or the trunk lines of sewer systems. The purpose of this paper is therefore to propose a theoretical approach to formulate a general governing equation set for modelling steady air movement in large sewer systems. This approach decomposes the sewer system of interest into its basic physical components as pipes and nodes, and builds local topology of each pipe and each node based on geographic information system data as the fundamentals of model formulation. It avoids manually identifying each branch of the sewer system, eliminates the effect of physically closed networks in sewer systems on the governing equations, and considers key sewer components and all known driving forces. The proposed approach was applied to a real sewer system with over 500 pipes. The results show that the proposed model is applicable in modelling air movement in a large sewer system and provides a general idea of sewer gases moving through the system and their emission.


Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 689
Author(s):  
Fabrice Rodriguez ◽  
Amélie-Laure Le Delliou ◽  
Hervé Andrieu ◽  
Jorge Gironás

Sewer systems affect urban soil characteristics and subsoil water flow. The direct connection observed between baseflow in sewer systems under drainage infiltrations and piezometric levels influences the hydrological behavior of urban catchments, and must consequently be considered in the hydrologic modeling of urban areas. This research studies the groundwater contribution to sewer networks by first characterizing the phenomenon using experimental data recorded on a small urban catchment in Nantes (France). Then, the model MODFLOW was used to simulate the infiltration of groundwater into a sewer network and model dry weather flows at an urban catchment scale. This application of MODFLOW requires representing, in a simplified way, the interactions between the soil and the sewer trench, which acts as a drain. Observed average groundwater levels were satisfactorily simulated by the model while the baseflow dynamics is well reproduced. Nonetheless, soil parameters resulted to be very sensitive, and achieving good results for joint groundwater levels and baseflow was not possible.


2010 ◽  
Vol 62 (5) ◽  
pp. 1090-1097 ◽  
Author(s):  
C. Urich ◽  
R. Sitzenfrei ◽  
M. Möderl ◽  
W. Rauch

The application of artificial case studies is a well established technique in urban drainage to test measures, approaches or models. However, the preparation of a virtual case study for a sewer system is a tedious task. Several algorithms have been presented in the literature for an automatic generation of virtual sewer systems. Applying the approach of generating virtual cities by means of the software VIBe (Virtual Infrastructure Benchmarking) the urban structure (including elevation map, land use and population distribution) is generated firstly and the infrastructure is designed meeting the requirements of the urban structure. The aim of this paper is the development of an agent based approach for generating virtual sewer systems. This new algorithm functions as module of the software VIBe but can of course also be applied to a real city in order to get information on possible/optimal sewer placement. Here hundred virtual VIBe cities and for each twelve virtual sewer networks are generated and calibrated based on data of an alpine region. It is revealed that with the approach presented virtual sewer networks which are comparable with real world sewer networks can be generated. The agent based method provides data sets for benchmarking and allows case independent testing of new measures.


1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).


2011 ◽  
Vol 63 (12) ◽  
pp. 2983-2991 ◽  
Author(s):  
M. Métadier ◽  
J. L. Bertrand-Krajewski

Continuous high resolution long term turbidity measurements along with continuous discharge measurements are now recognised as an appropriate technique for the estimation of in sewer total suspended solids (TSS) and Chemical Oxygen Demand (COD) loads during storm events. In the combined system of the Ecully urban catchment (Lyon, France), this technique is implemented since 2003, with more than 200 storm events monitored. This paper presents a method for the estimation of the dry weather (DW) contribution to measured total TSS and COD event loads with special attention devoted to uncertainties assessment. The method accounts for the dynamics of both discharge and turbidity time series at two minutes time step. The study is based on 180 DW days monitored in 2007–2008. Three distinct classes of DW days were evidenced. Variability analysis and quantification showed that no seasonal effect and no trend over the year were detectable. The law of propagation of uncertainties is applicable for uncertainties estimation. The method has then been applied to all measured storm events. This study confirms the interest of long term continuous discharge and turbidity time series in sewer systems, especially in the perspective of wet weather quality modelling.


2002 ◽  
Vol 46 (6-7) ◽  
pp. 379-387
Author(s):  
D. Jacobi ◽  
K.-J. Sympher

Berlin Wasserbetriebe is in need of a significant and longterm investment in the rehabilitation of its sewer system. With ratification of the European Standard EN 752 Part 5, comprehensive rules have been set out for the rehabilitation of drain and sewer systems: hydraulic performance, environmental impact and structural integrity of complete catchment areas are given equal consideration. Taking this into account, Berliner Wasserbetriebe has developed a sewer rehabilitation strategy. Economic aspects are integrated with a cost-benefit-analysis; the significance of the remaining useful life of a pipe section is examined.


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