Long term pollution simulation in combined sewer networks

2001 ◽  
Vol 43 (7) ◽  
pp. 83-89 ◽  
Author(s):  
B. Masse ◽  
M. Zug ◽  
J. P. Tabuchi ◽  
B. Tisserand
Keyword(s):  
Conceptual Model ◽  
Combined System ◽  
Sewerage System ◽  
Sewer Network ◽  
Reference Flow ◽  
Combined Sewer ◽  
Stream System ◽  
Long Time ◽  
Sewer Networks

This paper presents results of long term pollution simulations on the example of the sewerage system of Grand-Couronne. This modelling work is part of a study where objective is to develop a method to define the reference flow of a WWTP. The model HYDROWORKS DM™ has been successfully validated in hydraulics and pollution for the sewer network, for long time simulations. A conceptual model has been built to model the pollution in the tank at the outlet of the combined system. One synthetic year of rain has been used to simulate the working of the “up stream system” of the WWTP (combined sewer + tank + separate sewer + pre-treatments) and has been successfully validated by measurements of the 1998-1999 year. If this paper is focused on the “up stream system”, the SIMBA/SIMBAD WWTP model has been successfully calibrated and validated too, and the combination represents a fully validated “Integrated Model” for the sewerage system.

Near bed solids transport rate prediction in a combined sewer network

1997 ◽  
Vol 36 (8-9) ◽  
pp. 129-134 ◽  
Author(s):  
Scott Arthur ◽  
Richard M. Ashley
Keyword(s):  
Prediction Equation ◽  
Subject Area ◽  
Future Research ◽  
Bed Load ◽  
Sewerage System ◽  
Solids Transport ◽  
Sewer Network ◽  
Combined Sewer ◽  
Mode Of Transport ◽  
Transport Prediction

The physical and biochemical nature of the material transported near the bed (‘bed-load’) in combined sewers is established. The merits of the recent evolution of the terminology used in this field are discussed. The physical characteristics of material found in transport at three separate combined sewer field sites are described. The importance of this mode of transport, in terms of the mass transported and pollutant potential, is demonstrated based on data collected from Dundee combined sewerage system sites. The development of a novel near bed solids transport prediction equation is described. Comparisons are made between measured near bed solids transport rates obtained in the field, at sites with and without deposited beds, with predictions obtained using the new methodology. The need for future research in this subject area is emphasised.

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.

Enhancing the power generation of Rhodopseudomonas palustris-based MFC

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1261-1268
Author(s):  
Shu Otani ◽  
Dang-Trang Nguyen ◽  
Kozo Taguchi
Keyword(s):  
Activated Carbon ◽  
Rhodopseudomonas Palustris ◽  
Ozone Treatment ◽  
Maximum Power Density ◽  
On Demand ◽  
Long Time ◽  
Dry Conditions ◽  
Carbon Sheet ◽  
Uv Ozone

In this study, a portable and disposable paper-based microbial fuel cell (MFC) was fabricated. The MFC was powered by Rhodopseudomonas palustris bacteria (R. palustris). An activated carbon sheet-based anode pre-loaded organic matter (starch) and R. palustris was used. By using starch in the anode, R. palustris-loaded on the anode could be preserved for a long time in dry conditions. The MFC could generate electricity on-demand activated by adding water to the anode. The activated carbon sheet anode was treated by UV-ozone treatment to remove impurities and to improve its hydrophilicity before being loaded with R. palustris. The developed MFC could generate the maximum power density of 0.9 μW/cm2 and could be preserved for long-term usage with little performance degradation (10% after four weeks).

Charlemagne’s Health in ‘Old Age’: Did It Affect Carolingian Military Strategy?

Mediaevistik ◽  
2020 ◽  
Vol 32 (1) ◽  
pp. 11-53
Author(s):  
Bernard S. Bachrach
Keyword(s):  
Old Age ◽  
The Political ◽  
Military Strategy ◽  
The West ◽  
Long Time

During the first thirty-three years of his reign as king of the Franks, i.e., prior to his coronation as emperor on Christmas day 800, Charlemagne, scholars generally agree, pursued a successful long-term offensive and expansionist strategy. This strategy was aimed at conquering large swaths of erstwhile imperial territory in the west and bringing under Carolingian rule a wide variety of peoples, who either themselves or their regional predecessors previously had not been subject to Frankish regnum.1 For a very long time, scholars took the position that Charlemagne continued to pursue this expansionist strategy throughout the imperial years, i.e., from his coronation on Christmas Day 800 until his final illness in later January 814. For example, Louis Halphen observed: “comme empereur, Charles poursuit, sans plus, l’oeuvre entamée avant l’an 800.”2 F. L. Ganshof, who also wrote several studies treating Charlemagne’s army, was in lock step with Halphen and observed: “As emperor, Charlemagne pursued the political and military course he had been following before 25 December 800.”3

CSO Modelling Considering Moving Storms and Tipping Bucket Gauge Failures

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
M. Hochedlinger ◽  
W. Sprung ◽  
H. Kainz ◽  
K. König
Keyword(s):  
Hydrological Models ◽  
Rain Intensity ◽  
Hydrodynamic Models ◽  
Data Intensive ◽  
Storm Flow ◽  
Cell Velocity ◽  
Combined Sewer ◽  
Moving Direction ◽  
The Difference

The simulation of combined sewer overflow volumes and loads is important for the assessment of the overflow and overflow load to the receiving water to predict the hydraulic or the pollution impact. Hydrodynamic models are very data-intensive and time-consuming for long-term quality modelling. Hence, for long-term modelling, hydrological models are used to predict the storm flow in a fast way. However, in most cases, a constant rain intensity is used as load for the simulation, but in practice even for small catchments rain occurs in rain cells, which are not constant over the whole catchment area. This paper presents the results of quality modelling considering moving storms depending on the rain cell velocity and its moving direction. Additionally, tipping bucket gauge failures and different corrections are also taken into account. The results evidence the importance of these considerations for precipitation due the effects on overflow load and show the difference up to 28% of corrected and uncorrected data and of moving rain cells instead of constant raining intensities.

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

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.

Technical solutions envisaged in managing solids in combined sewer networks

1996 ◽  
Vol 33 (9) ◽  
pp. 237-244 ◽  
Author(s):  
Ghassan Chebbo ◽  
Dominique Laplace ◽  
André Bachoc ◽  
Yves Sanchez ◽  
Benoit Le Guennec
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Drainage Area ◽  
Bed Load ◽  
Urban Drainage ◽  
Combined Sewer ◽  
Wet Weather ◽  
Technical Solutions ◽  
Dry Weather Flow ◽  
Sewer Networks

Solids in combined sewer networks represent two important technical questions: - the clogging of man-entry sewers, and - pollution in urban wet weather discharges, whose main vectors are generally suspended solids. In this paper, we shall present first, curative technical solutions which avoid or remove deposits in man-entry sewers. We shall discuss the partial extraction of the largest solids; selective trapping of bed load solids, which form deposits; and the displacement of deposits using dry weather flow flushing waves. We shall then examine technical solutions to control pollution in urban wet weather discharges. This will show that decantation is an efficient means of fighting pollution. However, it is not always feasible because it involves large scale investments. Complementary methods should, therefore, be developed and used at different points in the water's passage through an urban drainage area.

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