COMPUTATIONAL MODELLING OF A VORTEX CSO STRUCTURE

1994 ◽  
Vol 30 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Adrian J. Saul ◽  
Karel Svejkovsky
Keyword(s):  
Particle Tracking ◽  
Computational Modelling ◽  
Terminal Velocity ◽  
Retention Performance ◽  
Sewer System ◽  
Retention Efficiency ◽  
Final Destination ◽  
Combined Sewer ◽  
Solids Separation ◽  
Individual Particles

Vortex combined sewer overtlow (CSO) structures with a peripheral spill weir are sometimes used within UK sewerage systems for the prevention of tlooding and the retention of pollutants within the sewer system. The velocity distribution within such a CSO chamber has been simulated using the 3D mathematical model FLUENT. Similarly the particle tracking routine of FLUENT has been utilised to predict the trajectory and final destination (treatment or spill) of individual particles with known size and terminal velocity which were introduced within the intlow to the chamber. From this data it has been possible to predict the solids separation retention efficiency for these particles and the results have been compared with previously published experimental data. Some agreement was observed between the two sets of results. The paper is concluded by a discussion concerning the capability and limitations of the FLUENT model to predict the hydraulic and pollutant retention performance of a Vortex CSO chamber.

Developments in a methodology for the design of engineered invert traps in combined sewer systems

2002 ◽  
Vol 45 (7) ◽  
pp. 133-142 ◽  
Author(s):  
A. Buxton ◽  
S. Tait ◽  
V. Stovin ◽  
A. Saul
Keyword(s):  
Particle Tracking ◽  
Laboratory Model ◽  
Sediment Retention ◽  
Sewer System ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Slot Size ◽  
Comparative Results ◽  
Trapping Performance ◽  
Stochastic Particle

Sediments within sewers can have a significant effect on the operation of the sewer system and on the surrounding natural and urban environment. One possible method for the management of sewer sediments is the use of slotted invert traps. Although invert traps can be used to selectively trap only inorganic bedload material, little is known with regard to the design of these structures. This paper presents results from a laboratory investigation comparing the trapping performance of three slot size configurations of a laboratory-scale invert trap. The paper also presents comparative results from a two-dimensional computational model utilising stochastic particle tracking. This investigation shows that particle tracking consistently over-predicts sediment retention efficiencies observed within the laboratory model.

Monitoring runoff conditions in a combined sewer system: experience and results of ten years' application

1996 ◽  
Vol 33 (1) ◽  
pp. 257-264
Author(s):  
M. Weyand
Keyword(s):  
Monitoring System ◽  
Pilot Project ◽  
Actual Condition ◽  
Real Time Control ◽  
Sewer System ◽  
Time Control ◽  
Combined Sewer ◽  
Complete Breakdown ◽  
Short Time ◽  
Detention Facilities

To get knowledge about the runoff, storage and combined sewer overflow (CSO) conditions since 1985 a measuring and monitoring system is working in the sewer network of the community Ense-Bremen (near Dortmund). Within this semi-urban catchment seven detention facilities are fitted out with devices for monitoring information about basin outflow, grade of volume and CSO. Since October 1986 the determined data are also used for the real-time control of that sewerage. Since its installation the monitoring system works rather satisfyingly. Especially the operating staff use its possibilities to get information about the actual condition of the sewer system. Thus, differences to the normal runoff conditions can be realised in very short time. That allows an immediate reaction in order to clear malfunctions or errors as well. However, within the ten years there have also occurred some failures at the measuring devices caused by different reasons up to a complete breakdown of the whole system during thunder-storms. All in all the results of that pilot project have been positive and are now the basis for the equipment of further detention facilities in other sewer systems with monitoring devices.

The Role of Computer Modeling in Combined Sewer Overflow Abatement Planning

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1831-1840 ◽  
Author(s):  
L. A. Roesner ◽  
E. H. Burgess
Keyword(s):  
System Modeling ◽  
Cost Effective ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
New Techniques ◽  
Hydraulic Simulation ◽  
Continuous Simulation ◽  
Combined Sewer ◽  
The U.S

Increased concern regarding water quality impacts from combined sewer overflows (CSOs) in the U.S. and elsewhere has emphasized the role of computermodeling in analyzing CSO impacts and in planning abatement measures. These measures often involve the construction of very large and costly facilities, and computer simulation during plan development is essential to cost-effective facility sizing. An effective approach to CSO system modeling focuses on detailed hydraulic simulation of the interceptor sewers in conjunction with continuous simulation of the combined sewer system to characterize CSOs and explore storage-treatment tradeoffs in planning abatement facilities. Recent advances in microcomputer hardware and software have made possible a number of new techniques which facilitate the use of computer models in CSO abatement planning.

Sewers and the Quality of Canals and Ditches in Amsterdam

1993 ◽  
Vol 27 (5-6) ◽  
pp. 61-67 ◽  
Author(s):  
E. Jacobs ◽  
J. W. van Sluis
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Sediment Quality ◽  
Water System ◽  
Water Systems ◽  
Sewer System ◽  
Water And Sediment ◽  
Combined Sewer ◽  
Water And Sediment Quality

The surface water system of Amsterdam is very complicated. Of two characteristic types of water systems the influences on water and sediment quality are investigated. The importance of the sewer output to the total loads is different for both water systems. In a polder the load from the sewers is much more important than in the canal basin. Measures to reduce the emission from the sewers are much more effective in a polder. The effect of these measures on sediment quality is more than the effect on water quality. Some differences between a combined sewer system and a separate sewer system can be found in sediment quality.

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.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

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).

Radar-aided CSO-control-criteria for an ecological approach

1997 ◽  
Vol 36 (8-9) ◽  
pp. 223-228
Author(s):  
A. Petruck ◽  
F. Sperling
Keyword(s):  
Critical Time ◽  
Integrated Approach ◽  
Control Measures ◽  
Real Time Control ◽  
Sewer System ◽  
Time Control ◽  
Physical Measurements ◽  
Combined Sewer ◽  
Receiving Stream ◽  
Control Criteria

The control strategy of a combined sewer system incorporating three stormwater storage tanks with overflows presented here attempts to consider all aspects of acute CSO effects. These are the hydraulic and the composition components as well as the time factor. The result is an integrated approach, which is not based on the classic emission view (i.e. reduction of volume), but on pollution criteria (i.e. possible harm to the biotic community). The aim is to reduce the exceeding of critical peak values of the CSO components at critical time intervals. Control decisions will be based on continuous measurements in the sewer system and in the receiving stream. Furthermore the measurements are carried out to determine the effects (both hydraulic and chemical) of particular CSO discharges in order to evolve the critical values for the project area. The chemical and physical measurements are accompanied by a biological monitoring programme. Macroinvertebrates are sampled upstream and downstream of outfalls and at a reference site. This allows the evaluation of the control measures on an ecological basis, and thus an assessment of the ecological potential of radar-aided real-time control of the combined sewer systems.

An application of Austrian legal requirements for CSO emissions

2011 ◽  
Vol 64 (5) ◽  
pp. 1081-1088 ◽  
Author(s):  
Manfred Kleidorfer ◽  
Wolfgang Rauch
Keyword(s):  
Model Calibration ◽  
Model Building ◽  
Treatment Plant ◽  
Cost Effective ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
Legal Requirements ◽  
Innovative Methods ◽  
Combined Sewer

The Austrian standard for designing combined sewer overflow (CSO) detention basins introduces the efficiency of the combined sewer overflows as an indicator for CSO pollution. Additionally criteria for the ambient water quality are defined, which comprehend six kinds of impacts. In this paper, the Austrian legal requirements are described and discussed by means of hydrological modelling. This is exemplified with the case study Innsbruck (Austria) including a description for model building and model calibration. Furthermore an example is shown in order to demonstrate how – in this case – the overall system performance could be improved by implementing a cost-effective rearrangement of the storage tanks already available at the inflow of the wastewater treatment plant. However, this guideline also allows more innovative methods for reducing CSO emissions as measures for better usage of storage volume or de-centralised treatment of stormwater runoff because it is based on a sewer system simulation.

Simulation and optimization of low impact development for mitigating combined sewer overflows associated with climate change

2019 ◽  
Author(s):  
◽  
Ali Shallal
Keyword(s):  
Urban Area ◽  
Kansas City ◽  
Low Impact Development ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
University Of Missouri ◽  
Simulation And Optimization ◽  
Time To Peak ◽  
Combined Sewer ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Modeling rainfall runoff can help to understand what is happening throughout the system, how can control of water to prevent flood, and how much the quality of runoff can change in urban area. Modeling sewer system help decision maker to indicate best strategy to prevent flooding, reduce runoff pollution, reduce cost of wastewater treatment and determine best suitable LID to an urban area. This dissertation first starting with analysis the complexity of model necessary to get accepted result in term peak flow, runoff volume, numbers of flooding nodes and time to peak. Modeling requirements may lead to system simplification, as in limiting the size of the pipes included in the analyses. Researchers analyzed the combined sewer system of the urbanized Town Fork Creek catchment in Kansas City, Missouri using PCSWMM to assess the potential impact of the simplifications on hydraulic results.

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