DESIGN OF STORMWATER INFILTRATION FOR REDUCTION OF COMBINED SEWER OVERFLOW (CSO)

1994 ◽  
Vol 30 (1) ◽  
pp. 53-61 ◽  
Author(s):  
C. O. Rosted Petersen ◽  
P. Jacobsen ◽  
P. S. Mikkelsen
Keyword(s):  
Optimal Solution ◽  
Combined Sewer Overflow ◽  
Return Periods ◽  
Sewer System ◽  
Impervious Area ◽  
Combined Sewer ◽  
Sewer Overflow ◽  
Applied Design ◽  
Design Return Periods ◽  
Stormwater Infiltration

Stormwater infiltration is a significant tool for combined sewer overflow abatement because it involves a decrease in the impervious area connected to the sewer system. When allowing the infiltration structures to overflow into the existing sewer it is shown that for a required reduction in CSO-volume there exists an unambiguous relation between the infiltration structure volume and the size of impervious area connected to infiltration. Further, the presence of an optimal solution minimizing the total trench volume is pointed out. For a Danish sewer system with a travel time of 30 min and an interceptor capacity of 0.2 μm/s the optimal solution for reducing the CSO-volumes by 40 percent involves connecting 65 percent of the impervious area to infiltration trenches with a total storage volume of 3.6 mm. This corresponds to designing the trenches according to an exceedence return period of 0.04 yrs compared to the commonly applied design return periods of 2 to 10 yrs.

Experience with Vortex Separators for Combined Sewer Overflow Control

1993 ◽  
Vol 27 (5-6) ◽  
pp. 93-104 ◽  
Author(s):  
H. Brombach ◽  
C. Xanthopoulos ◽  
H. H. Hahn ◽  
W. C. Pisano
Keyword(s):  
Separation Efficiency ◽  
Operational Reliability ◽  
Second Phase ◽  
Combined Sewer Overflow ◽  
Specific Storage ◽  
Impervious Area ◽  
Evaluation Phase ◽  
Combined Sewer ◽  
Sewer Overflow ◽  
Overflow Control

In 1987 the first vortex solids separator facility in Germany was installed for combined sewer overflow (CSO) control. The separation efficiency was optimized in the hydraulic laboratory using scaled down models with artificial tracers to simulate typical sewage particulates. The station has two parallel operating vortex separators and serves a connected and impervious area of about 11 hectares (ha) and 1,500 people. The specific storage volume of the station is 7.2 m3 per ha. Two evaluation programs were conducted. The first evaluation phase noted the operational reliability, hydraulic loads, overflow frequencies and water mass balances. The second phase monitored separation efficiencies. The evaluation showed that vortex solids separators are now ready for use in CSO control.

Real Time Control in Part of Copenhagen

1993 ◽  
Vol 27 (12) ◽  
pp. 209-212 ◽  
Author(s):  
Jørgen Jens Linde-Jensen
Keyword(s):  
Real Time ◽  
Storage Capacity ◽  
Combined Sewer Overflow ◽  
Real Time Control ◽  
Sewer System ◽  
Time Control ◽  
Combined Sewer ◽  
Sewer Overflow

The application of real-time control to the sewer system in a district of Copenhagen is described. It enables the storage capacity of the sewer system to be better utilised, thus minimizing combined sewer overflow pollution.

Comparison of conventional rule based flow control with control processes based on fuzzy logic in a combined sewer system

2002 ◽  
Vol 46 (6-7) ◽  
pp. 77-84 ◽  
Author(s):  
K. Klepiszewski ◽  
T.G. Schmitt
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Control ◽  
Flow Control ◽  
Control Systems ◽  
Combined Sewer Overflow ◽  
Sewer System ◽  
Rule Based ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Sewer Overflow

While conventional rule based, real time flow control of sewer systems is in common use, control systems based on fuzzy logic have been used only rarely, but successfully. The intention of this study is to compare a conventional rule based control of a combined sewer system with a fuzzy logic control by using hydrodynamic simulation. The objective of both control strategies is to reduce the combined sewer overflow volume by an optimization of the utilized storage capacities of four combined sewer overflow tanks. The control systems affect the outflow of four combined sewer overflow tanks depending on the water levels inside the structures. Both systems use an identical rule base. The developed control systems are tested and optimized for a single storm event which affects heterogeneously hydraulic load conditions and local discharge. Finally the efficiencies of the two different control systems are compared for two more storm events. The results indicate that the conventional rule based control and the fuzzy control similarly reach the objective of the control strategy. In spite of the higher expense to design the fuzzy control system its use provides no advantages in this case.

Monitoring in inline storage sewers for stormwater treatment to determine efficiencies

2004 ◽  
Vol 50 (11) ◽  
pp. 89-96
Author(s):  
T. Frehmann ◽  
T. Mietzel ◽  
R. Kutzner ◽  
B. Spengler ◽  
W.F. Geiger
Keyword(s):  
Water Samples ◽  
Monitoring Station ◽  
Total Efficiency ◽  
Combined Sewer Overflow ◽  
Stormwater Treatment ◽  
Erosion Process ◽  
Sewer System ◽  
Combined Sewer ◽  
Sewer Overflow ◽  
Reducing Costs

A special structure of combined sewer overflow tanks is the inline storage sewer with downstream discharge (SKU). This layout has the advantage that besides the sewer system, no other structures are required for storm water treatment. Consequently only very little space is required and compared to combined sewer overflow tanks, there is an enormous potential in reducing costs during construction. To investigate the efficiency of an inline storage sewer, a monitoring station was established in Dortmund-Scharnhorst, Germany. The monitoring station was in operation for a period of 2.5 years. Within this period water samples were taken during a total of 20 discharge events. Besides the complete hydraulic data collection, seven water samplers took more than 5,000 water samples during dry and wet weather. This adds up to a total of more than 20,000 individual lab analyses. The average of the total efficiency for the SKU-West is 86%. 29% of this efficiency can be attributed to the throttle flow. The remaining 57% can be divided into a part of 48% that can be attributed to the process storage and 9% that can be attributed to sedimentation and erosion process.

Combined sewer overflow over an oblique weir at Rat Creek in Edmonton, Alberta

2010 ◽  
Vol 37 (3) ◽  
pp. 477-488
Author(s):  
Elizabeth Valentine ◽  
Kurt Kronebusch ◽  
David Z. Zhu ◽  
N. Rajaratnam ◽  
Sid Lodewyk ◽  
...  
Keyword(s):  
Urban Drainage ◽  
Combined Sewer Overflow ◽  
Rating Curve ◽  
Flow Conditions ◽  
Sewer System ◽  
Sewer Systems ◽  
Model Study ◽  
Combined Sewer ◽  
Sewer Overflow

Oblique weirs are commonly used in urban drainage systems to remove excess flow from a sewer, in particular, a combined sewer system that has limited conveyance capacity. It is important to understand the hydraulics of these weirs to properly monitor the amount of the overflows as well as to design and improve sewer systems. The Rat Creek structure in Edmonton, Alberta, is a combined sewer overflow structure with a weir at an oblique alignment to the centerline of the sewer. A physical model study of the structure was conducted. The results show that both the approach flow conditions and the chamber geometry can significantly affect the hydraulic performance of the weir and invalidate the application of standard weir equations. A unique flow regime with a linear head–discharge rating curve was observed. The effects of modifying the weir and the hanging baffle wall downstream of the weir were also studied and reported. The results of this case study help to improve the understanding of the hydraulics of oblique weirs in sewer systems.

Evaluation of effectiveness of combined sewer overflow control measures by operational data

2011 ◽  
Vol 63 (2) ◽  
pp. 325-330 ◽  
Author(s):  
K. Schroeder ◽  
M. Riechel ◽  
A. Matzinger ◽  
P. Rouault ◽  
H. Sonnenberg ◽  
...  
Keyword(s):  
Rainfall Data ◽  
Control Measures ◽  
Combined Sewer Overflow ◽  
Sewer System ◽  
Combined Sewer ◽  
Efficiency Control ◽  
Sewer Overflow ◽  
Overflow Control ◽  
Term Data

The effect of combined sewer overflow (CSO) control measures should be validated during operation based on monitoring of CSO activity and subsequent comparison with (legal) requirements. However, most CSO monitoring programs have been started only recently and therefore no long-term data is available for reliable efficiency control. A method is proposed that focuses on rainfall data for evaluating the effectiveness of CSO control measures. It is applicable if a sufficient time-series of rainfall data and a limited set of data on CSO discharges are available. The method is demonstrated for four catchments of the Berlin combined sewer system. The analysis of the 2000–2007 data shows the effect of CSO control measures, such as activation of in-pipe storage capacities within the Berlin system. The catchment, where measures are fully implemented shows less than 40% of the CSO activity of those catchments, where measures have not yet or not yet completely been realised.

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