A Network Algorithm for the Optimum Operation of Urban Drainage Systems

The objective is to route sewage through a combined sewer by means of a real time control system. The task is formulated as a mathematical network optimization problem. The sewer system is simplified to be a set of linearly operating nodes and arcs. Tests indicate that the results obtained are comparable to linear programming solutions. However, much larger systems can be handled. The algorithm is fast enough to have it applied on AT-PC's for real world sewer systems.

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Real-time control of sewer systems using turbidity measurements

Water Science & Technology ◽

10.2166/wst.2011.159 ◽

2011 ◽

Vol 63 (11) ◽

pp. 2628-2632 ◽

Cited By ~ 11

Author(s):

C. Lacour ◽

M. Schütze

Keyword(s):

Real Time ◽

Measurement Techniques ◽

Quality Characteristics ◽

Water Quantity ◽

Urban Drainage ◽

Data Sets ◽

Real Time Control ◽

Time Control ◽

Sewer Systems ◽

Combined Sewer

Real-time control (RTC) of urban drainage systems has been proven useful as a means to reduce pollution by combined sewer overflow discharges. So far, RTC has been investigated mainly with a sole focus on water quantity aspects. However, as measurement techniques for pollution of wastewater are advancing, pollution-based RTC might be of increasing interest. For example, turbidity data sets from an extensive measurement programme in two Paris catchments allow a detailed investigation of the benefits of using pollution-based data for RTC. This paper exemplifies this, comparing pollution-based RTC with flow-based RTC. Results suggest that pollution-based RTC indeed has some potential, particularly when measurements of water-quality characteristics are readily available.

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Nowcasting of rainfall and of combined sewage flow in urban drainage systems

Water Science & Technology ◽

10.2166/wst.2009.098 ◽

2009 ◽

Vol 59 (6) ◽

pp. 1145-1151 ◽

Cited By ~ 19

Author(s):

Stefan Achleitner ◽

Stefan Fach ◽

Thomas Einfalt ◽

Wolfgang Rauch

Keyword(s):

Spatial Scales ◽

Radar Data ◽

Urban Drainage ◽

Real Time Control ◽

Sewer System ◽

Drainage Systems ◽

Time Control ◽

Sewer Systems ◽

Urban Drainage Systems ◽

The City

Nowcasting of rainfall may be used additionally to online rain measurements to optimize the operation of urban drainage systems. Uncertainties quoted for the rain volume are in the range of 5% to 10% mean square error (MSE), where for rain intensities 45% to 75% MSE are noted. For larger forecast periods up to 3 hours, the uncertainties will increase up to some hundred percents. Combined with the growing number of real time control concepts in sewer systems, rainfall forecast is used more and more in urban drainage systems. Therefore it is of interest how the uncertainties influence the final evaluation of a defined objective function. Uncertainty levels associated with the forecast itself are not necessarily transferable to resulting uncertainties in the catchment's flow dynamics. The aim of this paper is to analyse forecasts of rainfall and specific sewer output variables. For this study the combined sewer system of the city of Linz in the northern part of Austria located on the Danube has been selected. The city itself represents a total area of 96 km2 with 39 municipalities connected. It was found that the available weather radar data leads to large deviations in the forecast for precipitation at forecast horizons larger than 90 minutes. The same is true for sewer variables such a CSO overflow for small sub-catchments. Although the results improve for larger spatial scales, acceptable levels at forecast horizons larger than 90 minutes are not reached.

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

Water Science & Technology ◽

10.2166/wst.1996.0025 ◽

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.

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

Water Science & Technology ◽

10.2166/wst.1997.0670 ◽

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.

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