Removal of the organic surface layer in combined sewer sediment using a flushing gate

2003 ◽  
Vol 47 (4) ◽  
pp. 19-26 ◽  
Author(s):  
D. Laplace ◽  
C. Oms ◽  
M. Ahyerre ◽  
G. Chebbo ◽  
J. Lemasson ◽  
...  
Keyword(s):  
Surface Layer ◽  
Organic Layer ◽  
First Flush ◽  
Pollution Load ◽  
Water Flows ◽  
Sources Of Pollution ◽  
Combined Sewer ◽  
Wet Weather ◽  
Different Sources ◽  
Sediment Interface

Recent research identified the different sources of pollution of wet weather Combined Sewers Overflows (CSOs): it appeared that the deposits in sewers, and especially an organic layer situated at the water-sediment interface, may contribute 40-70% to the total pollution load of CSOs. Using the cyclic flush Hydrass gate, we generated increased water flows during dry weather. The effects of flushing the deposits have been analysed: the eroded particles sampled during the first flush wave show pollutant characteristics similar to characteristics measured in the organic layer. The organic layer that has formed on the surface of deposits can thus be washed off before rainstorms occur using the cyclic flushing technique.

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.

Nature and dynamic behaviour of organic surface layer deposits during dry weather

2005 ◽  
Vol 52 (3) ◽  
pp. 103-110 ◽  
Author(s):  
C. Oms ◽  
M.C. Gromaire ◽  
G. Chebbo
Keyword(s):  
Surface Layer ◽  
Dynamic Behaviour ◽  
Organic Layer ◽  
Combined Sewer Overflows ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Combined Sewer ◽  
In Situ Observations ◽  
Sediment Interface

In-situ observations were performed at two different spatial and temporal scales, in order to get a better identification of the nature of the organic layer situated at the water–sediment interface, and which had previously been identified as major of combined sewer overflows organic loads. Its composition and its build up mechanisms during dry weather periods are presented. Results showed that the concept of dry weather accumulation and more generally the way organic sewer sediments are modelled needs to be reconsidered.

Sterols: a tracer of organic matter in combined sewers

2008 ◽  
Vol 57 (11) ◽  
pp. 1705-1712 ◽  
Author(s):  
S. Zgheib ◽  
M. C. Gromaire ◽  
C. Lorgeoux ◽  
M. Saad ◽  
G. Chebbo
Keyword(s):  
Organic Pollution ◽  
Organic Layer ◽  
Runoff Water ◽  
Sewer System ◽  
Total Absence ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Receiving Waters ◽  
Wet Weather ◽  
Organic Particles

The important organic pollution of combined wet weather flows (WWF), its acute impact on receiving waters have been widely demonstrated. The main three possibly origins for this organic pollution are: runoff water (streets and roofs), wastewater and erosion of sewer sediments in combined sewer system. This work, for tracing the origin of organic particles bound in combined sewer system, has been focused on the innovative use of sterols. So, eight sterols have been selected and analysed for each kind of sample. Results are represented in contents of sterols (μg g−1) and in sterol profiles (%).The comparison of contents and profiles leads the separation between two groups: runoff water, characterized by the total absence of coprostanol, epicoprostanol and coprostanone, and the group of sewer deposits (gross bed sediment (GBS), organic layer (OL), biofilms) and wastewater. Moreover, sewer deposits and wastewater can be distinguished by their sterol contents and profiles. To evaluate their contribution to WWF a comparison between sterol signatures is done which shows that these effluents have a strong similarity in profiles and in contents of sterols to the organic layer.

scholarly journals Turbidity in Combined Sewer Sewage: An Identification of Stormwater Detention Tanks

2020 ◽  
Vol 17 (9) ◽  
pp. 3053
Author(s):  
Yang Liu ◽  
Liangang Hou ◽  
Wei Bian ◽  
Banglei Zhou ◽  
Dongbo Liang ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Surface Water Quality ◽  
First Flush ◽  
Combined Sewer Overflow ◽  
Detention Tank ◽  
Detection Approach ◽  
Combined Sewer ◽  
Wet Weather ◽  
Sewer Overflow ◽  
First Flush Effect

Combined sewer overflow remains a major threat to surface water quality. A stormwater detention tank is an effective facility to control combined sewer overflow. In this study, a new method for the selective collection of combined sewer sewage during wet weather based on real-time turbidity control is established to reduce the load of pollutants entering a river using a stormwater detention tank with a limited volume. There was a good correlation found between turbidity and the concentrations of total suspended solids (TSS) (R2 = 0.864, p < 0.05), total phosphorus (TP) (R2 = 0.661, p < 0.01), and chemical oxygen demand (COD) (R2 = 0.619, p < 0.01). This study shows that turbidity can be used to indicate the concentration of TSS, TP, and COD in the sewage of the combined sewer systems in wet weather. Based on the adopted first flush detection approach, total nitrogen (TN) and TP showed the first flush effect, whereas the first flush effect of TSS and COD was not obvious. The results show that it is impossible to effectively control combined sewer overflow by only treating the initial rainwater.

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.

Comparison of the efficiency of best stormwater management practices in urban drainage systems

1999 ◽  
Vol 39 (9) ◽  
pp. 269-276 ◽  
Author(s):  
R. Mehler ◽  
M. W. Ostrowski
Keyword(s):  
Stormwater Management ◽  
Management Practices ◽  
Alternative Methods ◽  
Urban Drainage ◽  
Pollution Load ◽  
Load Model ◽  
Urban Stormwater Management ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Stormwater Management Practices

Increasingly extended and alternative methods for urban stormwater management have been discussed in Germany and elsewhere. Without question an economically and ecologically sound combination of central and decentral measures will be a concept of the future. Yet, at present the introduction of approaches other than traditional combined sewer systems is restricted due to missing planning tools and technologies. Adding a number of frequently used Best Stormwater Management Practices (BSMP's) has widely extended the applicability of an existing stormwater water balance and pollution load model.

Technical solutions envisaged in managing solids in combined sewer networks

1996 ◽  
Vol 33 (9) ◽  
pp. 237-244 ◽  
Author(s):  
Ghassan Chebbo ◽  
Dominique Laplace ◽  
André Bachoc ◽  
Yves Sanchez ◽  
Benoit Le Guennec
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Drainage Area ◽  
Bed Load ◽  
Urban Drainage ◽  
Combined Sewer ◽  
Wet Weather ◽  
Technical Solutions ◽  
Dry Weather Flow ◽  
Sewer Networks

Solids in combined sewer networks represent two important technical questions: - the clogging of man-entry sewers, and - pollution in urban wet weather discharges, whose main vectors are generally suspended solids. In this paper, we shall present first, curative technical solutions which avoid or remove deposits in man-entry sewers. We shall discuss the partial extraction of the largest solids; selective trapping of bed load solids, which form deposits; and the displacement of deposits using dry weather flow flushing waves. We shall then examine technical solutions to control pollution in urban wet weather discharges. This will show that decantation is an efficient means of fighting pollution. However, it is not always feasible because it involves large scale investments. Complementary methods should, therefore, be developed and used at different points in the water's passage through an urban drainage area.

The nature and pollutant role of solids at the water-sediment interface in combined sewer networks

2003 ◽  
Vol 47 (4) ◽  
pp. 1-10 ◽  
Author(s):  
G. Chebbo ◽  
R. Ashley ◽  
M.-C. Gromaire
Keyword(s):  
Current Knowledge ◽  
Pollution Potential ◽  
Combined Sewer ◽  
New Ideas ◽  
Transport Modes ◽  
Sediment Interface ◽  
Sewer Networks

Solids at the water-sediment interface in combined sewers are known to be important for pollution potential during storm washout via CSOs. They have been investigated in several studies, but nonetheless, little is known about the origins, build-up, transport and nature of these solids. From a review of current knowledge, it is apparent that whilst there is general agreement that these solids are largely organic and have high polluting potential, their modes of transport and definition are not generally agreed upon. It is possible that there may be several “types” of these solids, defined as either: “near bed solids” or “fluid sediments/dense undercurrents”, possibly representing transport modes in flows with different ranges of ambient (dry weather) velocities and with differing sewerage layouts. Current knowledge is presented and new ideas for resolving the uncertainties regarding the nature, movement and effects of this material are outlined.

scholarly journals 23 Science and the International Regulation of Marine Pollution

2015 ◽  
Author(s):  
Kirk Elizabeth A
Keyword(s):  
Decision Making ◽  
Historical Development ◽  
Final Section ◽  
Marine Pollution ◽  
Management Approach ◽  
International Regulation ◽  
Sources Of Pollution ◽  
Similarities And Differences ◽  
Different Sources

This chapter considers the approaches taken by international regimes to address marine pollution. It identifies similarities and differences in approaches across time and different sources of pollution, the degree to which they follow an adaptive management approach, and the role of science in decision-making. It begins with an overview of the historical development of the law. It then discusses the current regime, covering general obligations and certain source-specific obligations. The final section contains conclusions and a discussion of current and future issues.

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