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.

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.

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.

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.

Comprehensive Planning of Urban Drainage and Wastewater Treatment

1993 ◽  
Vol 27 (12) ◽  
pp. 205-208
Author(s):  
Dirk-Th Kollatsch
Keyword(s):  
Wastewater Treatment ◽  
Transport Model ◽  
Drainage System ◽  
Simulation Models ◽  
Urban Drainage ◽  
Sewer Systems ◽  
Priority Task ◽  
Treatment Facilities ◽  
Receiving Waters ◽  
Pollution Impacts

For upgrading the urban drainage system (UDS) the reduction of pollution impacts is the priority task concerning the environmental protection of the receiving waters. With simulation models the interactions between surface, sewer systems, overflow structures and treatment facilities within the UDS can be shown. Models to simulate the pollutant impacts, transport and the effects on the receiving waters are available. In a first step a pollutant transport model of sewer systems and a model to simulate the wastewater treatment processes are connected. With these models the efficiency of upgrading measures can be checked in all parts of urban drainage systems.

Total Discharges Taken into Account for Comprehensive Planning of Urban Drainage and Waste Water Treatment

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2609-2612
Author(s):  
D.-Th. Kollatsch
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
Simulation Models ◽  
Urban Drainage ◽  
Comprehensive Planning ◽  
Environmental Care ◽  
Sewer Systems ◽  
Treatment Facilities ◽  
Receiving Waters

The most important task of urban drainage and waste water treatment in the future is the environmental care of rivers and receiving waters. For this it is necessary to have a look at all discharges of sewer systems and treatment facilities. With simulation models the interactions between surface, sewer systems, overflow structures and treatment facilities can be shown. With these models the efficiency of upgrading measures can be proved in all parts of urban water systems.

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.

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