Reduction of Combined Sewer Overflow Pollution Loads by Detention of Sanitary Sewage

1990 ◽  
Vol 22 (10-11) ◽  
pp. 205-212
Author(s):  
W. Schilling ◽  
D. T. Kollatsch
Keyword(s):  
High Strength ◽  
Chemical Transformations ◽  
Storage Tanks ◽  
Combined System ◽  
System A ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Separate System ◽  
Using Data ◽  
Operational Aspects

For mixed combined/separate sewer systems it is proposed, in times of combined sewage overflows (CSO), to store sanitary sewage at the inlet point to the combined system. Thereby, sanitary sewage (with high strength) is kept in the system for further treatment after the storm whereas less-polluted CSO are diverted to the receiving water. By using data of an existing catchment different scenarios are evaluated and the potential benefit of sanitary sewage detention is quantified. This approach is compared to current German CSO regulations. It is more effective than conventional CSO detention if more than 60 % of the population upstream of the CSO diversion are served by a separate system. A key problem of this concept is the control strategy that determines when to activate and empty the storage tanks. A number of criteria are compared. Considerations are also made on operational aspects such as chemical transformations in stored sewage, maximum allowable detention time, and cleansing of storage tanks.

A new database on urban runoff pollution: comparison of separate and combined sewer systems

2005 ◽  
Vol 51 (2) ◽  
pp. 119-128 ◽  
Author(s):  
H. Brombach ◽  
G. Weiss ◽  
S. Fuchs
Keyword(s):  
Treatment Plant ◽  
Pollution Load ◽  
Combined System ◽  
Concentration Data ◽  
Measured Concentration ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Long Time ◽  
Separate System ◽  
Receiving Waters

For a long time people have questioned what the “best” sewer system is for limiting the pollution load released into the receiving waters. In this paper the traditional separate and combined sewer systems are compared using a pollution load balance. The investigation is based on measured concentration data for a range of pollutant parameters in the sewer from the new database “ATV-DVWK Datenpool 2001”. The approach also accounted for the wastewater treatment plant outflow which contributes to the total pollutant load considerably. In spite of a number of neglected effects, the results show that the separate system is superior to the combined for some parameters only, such as nutrients, whereas for other parameters, e.g. heavy metals and COD, the combined system yields less total loads. Any uncritical preference of the separate system as a particularly advantageous solution is thus questionable. Individual investigations case by case are recommended.

scholarly journals Using data from monitoring combined sewer overflows to assess, improve, and maintain combined sewer systems

2015 ◽  
Vol 505 ◽  
pp. 1053-1061 ◽  
Author(s):  
A. Montserrat ◽  
Ll. Bosch ◽  
M.A. Kiser ◽  
M. Poch ◽  
Ll. Corominas
Keyword(s):  
Combined Sewer Overflows ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
Using Data

Characteristics of stormwater runoff and its control in Japan

1997 ◽  
Vol 36 (8-9) ◽  
pp. 141-147 ◽  
Author(s):  
Konomu Uchimura ◽  
Eiichi Nakamura ◽  
Shoichi Fujita
Keyword(s):  
Simulation Models ◽  
Heavy Rain ◽  
Simulation Method ◽  
Living Environment ◽  
Detention Ponds ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Separate System ◽  
New Research ◽  
And Control

To improve the living environment in Japanese cities, both combined type and separate type sewer systems are being provided to cope with rainwater and sewerage. However, during heavy rain, overflows are causing pollution of the rivers or lakes at the discharge destinations. In response to this problem, river management authorities in Japan have been studying the discharge load on combined sewer systems during rainfall and have established a simulation method to enable its prediction. As a result, the control of discharge loads by means of detention ponds has been effectively carried out in various cities in Japan. In addition, in recent years the separate system, that was thought to result in relatively good water quality, has been found to cause adverse effects as a non-point source of pollution in lakes and rivers at discharge destinations. For this reason, simulation models are being developed for the case of separate systems for several cities to accurately determine the discharge loads during rainfall. In this paper, as well as describing the discharge loads and control during rainfall for combined sewer systems in Japan, a report is given of the results of new research in regard to the discharge loads occurring in the case of separate sewer systems.

Combined sewer system versus separate system – a comparison of ecological and economical performance indicators

2007 ◽  
Vol 55 (4) ◽  
pp. 255-264 ◽  
Author(s):  
S. De Toffol ◽  
C. Engelhard ◽  
W. Rauch
Keyword(s):  
Water Quality ◽  
River Water ◽  
River Water Quality ◽  
Sewer System ◽  
Effect Analysis ◽  
System A ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Separate System ◽  
The Cost

This paper aims at comparing the cost-effectiveness of the two main types of urban drainage systems, that is, the combined sewer system and the separate sewer system, based on the analysis of simulations. The problem of which of the two systems is better was heavily discussed over the years and the answer given to the question was usually: ‘it depends’. In this work, specific impacts are investigated in terms of a cause–effect analysis. The results are subsequently summarized and can help in the choice of the system to be implemented. Despite earlier reasoning, studies on river water quality strongly indicate that the separate system is not always the preferable solution because the polluted runoff from the street, containing e.g. different heavy metals, is discharged directly into the river. This analysis aims to compare the two different sewer systems on the basis of literature data and simulation of specific cases. The results are evaluated, as suggested in the EU-Water Framework Directive, on the basis of different assessment criteria: river water quality and morphology impacts, emissions and costs.

Long-Term Simulation of Pollutant Loads in Treatment Plant Effluents and Combined Sewer Overflows

1990 ◽  
Vol 22 (10-11) ◽  
pp. 69-76 ◽  
Author(s):  
A. Durchschlag
Keyword(s):  
Waste Water Treatment ◽  
Treatment Plant ◽  
Storm Water ◽  
Water Runoff ◽  
Storage Tanks ◽  
Combined Sewer Overflows ◽  
Storm Water Runoff ◽  
Combined Sewer ◽  
Hydraulic Load ◽  
Water Tanks

As a result of urbanization, the pollutant discharges from sources such as treatment plant effluents and polluted stormwaters are responsible for an unacceptable water quality in the receiving waters.In particular, combined sewer system overflows may produce great damage due to a shock effect. To reduce these combined sewer overflow discharges, the most frequently used method is to build stormwater storage tanks. During storm water runoff, the hydraulic load of waste water treatment plants increases with additional retention storage. This might decrease the treatment efficiency and thereby decrease the benefit of stormwater storage tanks. The dynamic dependence between transport, storage and treatment is usually not taken into account. This dependence must be accounted for when planning treatment plants and calculating storage capacities in order to minimize the total pollution load to the receiving waters. A numerical model will be described that enables the BOD discharges to be continuously calculated. The pollutant transport process within the networks and the purification process within the treatment plants are simulated. The results of the simulation illustrate; a statistical balance of the efficiency of stormwater tanks with the treatment plant capacity and to optimize the volume of storm water tanks and the operation of combined sewer systems and treatment plants.

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.

Methods for studying dissolved oxygen levels in coastal and estuarine waters receiving combined sewer overflows

1995 ◽  
Vol 32 (2) ◽  
pp. 95-103
Author(s):  
José A. Revilla ◽  
Kalin N. Koev ◽  
Rafael Díaz ◽  
César Álvarez ◽  
Antonio Roldán
Keyword(s):  
Dissolved Oxygen ◽  
Coastal Waters ◽  
Computational Cost ◽  
Oxygen Deficit ◽  
Alternative Methods ◽  
Coastal Zones ◽  
Combined Sewer Overflows ◽  
Sewer Systems ◽  
Combined Sewer ◽  
High Computational Cost

One factor in determining the transport capacity of coastal interceptors in Combined Sewer Systems (CSS) is the reduction of Dissolved Oxygen (DO) in coastal waters originating from the overflows. The study of the evolution of DO in coastal zones is complex. The high computational cost of using mathematical models discriminates against the required probabilistic analysis being undertaken. Alternative methods, based on such mathematical modelling, employed in a limited number of cases, are therefore needed. In this paper two alternative methods are presented for the study of oxygen deficit resulting from overflows of CSS. In the first, statistical analyses focus on the causes of the deficit (the volume discharged). The second concentrates on the effects (the concentrations of oxygen in the sea). Both methods have been applied in a study of the coastal interceptor at Pasajes Estuary (Guipúzcoa, Spain) with similar results.

Methods of Estimating the Discharge of Gross Solids from Combined Sewer Systems

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1295-1304 ◽  
Author(s):  
C. Jefferies
Keyword(s):  
Research Centre ◽  
Combined Sewer Overflows ◽  
Water Research ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
The Uk

Visible pollution discharged from two combined sewer overflows were studied using passive Trash Trap devices and the UK Water Research Centre Gross Solids Sampler. Relationships are presented for the number of visible solids and the mass of gross solids discharged during an event. The differences in the behaviour of the overflow types are reported on and they are categorised using the Trash Traps.

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.

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