Origins and characteristics of urban wet weather pollution in combined sewer systems: the experimental urban catchment “Le Marais” in Paris

1998 ◽  
Vol 37 (1) ◽  
Keyword(s):  
Urban Catchment ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather

Origins and characteristics of urban wet weather pollution in combined sewer systems: the experimental urban catchment “Le Marais” in Paris

1998 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Marie-Christine Gromaire-Mertz ◽  
Ghassan Chebbo ◽  
Mohamed Saad
Keyword(s):  
Waste Water ◽  
Sewer System ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Sources Of Pollution ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather ◽  
Wet Weather Flow ◽  
Different Sources

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.

The Erosion and Movement of Sediments and Associated Pollutants in Combined Sewers

1992 ◽  
Vol 25 (8) ◽  
pp. 101-114 ◽  
Author(s):  
R. M. Ashley ◽  
D. J. J. Wotherspoon ◽  
B. P. Coghlan ◽  
I. McGregor
Keyword(s):  
Field Data ◽  
Bed Load ◽  
Surficial Sediments ◽  
Sediment Erosion ◽  
Weak Layer ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather ◽  
Wet Weather Flow

The complex and inhomogeneous nature of sediments in sewers, and the variability of the particles and dissolved substances flowing in dry and wet weather combined sewage, make the prediction of sediment erosion and pollutant release a difficult proposition. It is apparent that the erosion of sediments in sewers can release pollutants in concentrations which exceed by many times the levels found in the various contributing sources of the sediments and pollutants, and whilst this release is normally in the form of an initial highly polluting foul flush at the start of wet weather flow, the occurrence of foul flushes has not been found to be ubiquitous, even from event to event in the same sewer. The origins of foul flushes may be attributable to the speedy erosion of a weak layer of highly concentrated surficial sediments (or bed-load) at the start of wet weather flows. Various models have been proposed, and some successfully applied to field data, to simulate the erosion and movement of sediments and associated pollutants in combined sewer systems.

Contributions of wastewater, runoff and sewer deposit erosion to wet weather pollutant loads in combined sewer systems

2010 ◽  
Vol 44 (20) ◽  
pp. 5875-5886 ◽  
Author(s):  
J. Gasperi ◽  
M.C. Gromaire ◽  
M. Kafi ◽  
R. Moilleron ◽  
G. Chebbo
Keyword(s):  
Pollutant Loads ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather

Settling Velocity Grading of Particle Bound PAHs: Case of Wet Weather Flows within Combined Sewer Systems

2009 ◽  
Vol 135 (11) ◽  
pp. 1155-1160 ◽  
Author(s):  
J. Gasperi ◽  
C. Lorgeoux ◽  
R. Moilleron ◽  
M.-C. Gromaire ◽  
G. Chebbo
Keyword(s):  
Settling Velocity ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather

scholarly journals Impact of Combined Sewer Systems on the Quality of Urban Streams: Frequency and Duration of Elevated Micropollutant Concentrations

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 850 ◽  
Author(s):  
Ulrich Dittmer ◽  
Anna Bachmann-Machnik ◽  
Marie A. Launay
Keyword(s):  
Aquatic Organisms ◽  
Urban Streams ◽  
Base Flow ◽  
Storm Events ◽  
Urban Catchment ◽  
Mixing Ratios ◽  
Sewer Systems ◽  
Wwtp Effluent ◽  
Wide Range ◽  
Combined Sewer

Water quality in urban streams is highly influenced by emissions from WWTP and from sewer systems particularly by overflows from combined systems. During storm events, this causes random fluctuations in discharge and pollutant concentrations over a wide range. The aim of this study is an appraisal of the environmental impact of micropollutant loads emitted from combined sewer systems. For this purpose, high-resolution time series of river concentrations were generated by combining a detailed calibrated model of a sewer system with measured discharge of a small natural river to a virtual urban catchment. This river base flow represents the remains of the natural hydrological system in the urban catchment. River concentrations downstream of the outlets are simulated based on mixing ratios of base flow, WWTP effluent, and CSO discharge. The results show that the standard method of time proportional sampling of rivers does not capture the risk of critical stress on aquatic organisms. The ratio between average and peak concentrations and the duration of elevated concentrations strongly depends on the source and the properties of the particular substance. The design of sampling campaigns and evaluation of data should consider these characteristics and account for their effects.

Separate and combined sewer systems: a long-term modelling approach

2009 ◽  
Vol 60 (3) ◽  
pp. 555-565 ◽  
Author(s):  
Giorgio Mannina ◽  
Gaspare Viviani
Keyword(s):  
Cost Benefit Analysis ◽  
Treatment Plant ◽  
Cost Benefit ◽  
Sewer System ◽  
Sewer Systems ◽  
System Versus ◽  
Combined Sewer ◽  
Wet Weather ◽  
Wet Weather Flow

Sewer systems convey mostly dry weather flow, coming from domestic and industrial sanitary sewage as well as infiltration flow, and stormwater due to meteoric precipitations. Traditionally, in urban drainage two types of sewer systems are adopted: separate and combined sewers. The former convey dry and wet weather flow separately into two different networks, while the latter convey dry and wet weather flow together. Which is the best solution in terms of cost-benefit analysis still remains a controversial subject. The present study was aimed at comparing the pollution loads discharged to receiving bodies by Wastewater Treatment Plant (WWTP) and Combined Sewer Overflow (CSO) for different kinds of sewer systems (combined and separate). To accomplish this objective, a comparison between the two systems was carried out using results from simulations of catchments characterised by different dimensions, population densities and water supply rate. The analysis was based on a parsimonious mathematical model able to simulate the sewer system as well as the WWTP during both dry and wet weather. The rain series employed for the simulations was six years long. Several pollutants, both dissolved and particulate, were modelled. The results confirmed the uncertainties in the choice of one system versus the other, emphasising the concept that case-by-case solutions have to be undertaken. Further, the compared systems showed different responses in terms of effectiveness in reducing the discharged mass to the RWB in relation to the particular pollutant taken into account.

Methods for Calculation of Annual and Extreme Overflow Events from Combined Sewer Systems

1984 ◽  
Vol 16 (8-9) ◽  
pp. 311-325 ◽  
Author(s):  
N B Johansen ◽  
P Harremoës ◽  
M Jensen
Keyword(s):  
Extreme Event ◽  
Short Term ◽  
Sewer Systems ◽  
Extreme Load ◽  
Combined Sewer ◽  
Receiving Waters ◽  
Water Problems ◽  
Source Of Pollution ◽  
Receiving Water

Overflow from combined systems constitute an increasing source of pollution of receiving waters, as compared to daily wastewater discharges which undergo treatment to a still higher extent. The receiving water problems from overflows are significant both in a long term scale (mean annual load) and in a short term scale (extreme event load). A method for computation of both annual and extreme load is presented. It is based on historical rain series and the use of a time-area model and simple pollutant mixing model in runoff calculation. Statistical calculations for both mean annual load and extreme events have been applied to the computed overflow series. Based on the computerized method simple manual calculations methods have been developed, resulting in graphs and tables for annual load and extreme load.

The first flush in sewer systems

1996 ◽  
Vol 33 (9) ◽  
pp. 101-108 ◽  
Author(s):  
Agnès Saget ◽  
Ghassan Chebbo ◽  
Jean-Luc Bertrand-Krajewski
Keyword(s):  
Treatment Strategy ◽  
Real Data ◽  
First Flush ◽  
Clear Definition ◽  
Controversial Subject ◽  
Sewer Systems ◽  
Wet Weather ◽  
Definition Of ◽  
Appearance Frequency

The first flush phenomenon of urban wet weather discharges is presently a controversial subject. Scientists do not agree with its reality, nor with its influences on the size of treatment works. Those disagreements mainly result from the unclear definition of the phenomenon. The objective of this article is first to provide a simple and clear definition of the first flush and then to apply it to real data and to obtain results about its appearance frequency. The data originate from the French database based on the quality of urban wet weather discharges. We use 80 events from 7 separately sewered basins, and 117 events from 7 combined sewered basins. The main result is that the first flush phenomenon is very scarce, anyway too scarce to be used to elaborate a treatment strategy against pollution generated by urban wet weather discharges.

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