A laboratory study of the erosion and transport of cohesive-like sediment mixtures in sewers

1998 ◽  
Vol 37 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Simon J. Tait ◽  
Peter J. Rushforth ◽  
Adrian J. Saul
Keyword(s):  
Laboratory Study ◽  
Significant Degree ◽  
Combined Sewer Overflows ◽  
Sewer Systems ◽  
Hydraulic Conditions ◽  
Combined Sewer ◽  
Water Courses ◽  
The Uk ◽  
Sediment Mixtures ◽  
Initial Results

Surveys of sewers in the UK have indicated that many sewer systems have significant in-sewer deposits. Many of these existing combined sewers have been constructed at such a gradient and experience such a range of hydraulic conditions that over a period of time they experience repeated phases of sediment deposition, erosion and transport. Deposition of sediment in sewers with its consequent loss of discharge capacity can lead to the surcharging of sewerage systems and the premature operation of combined sewer overflows. The sudden erosion and transport of large quantities of deposited in-sewer sediments during periods of increased flow can significantly contribute to the pollution load imposed on receiving water courses and sewerage treatment plants. It is therefore important not only to be able to estimate the hydraulic performance of sewers but also the conditions under which significant erosion of deposited sediments occur. This paper reports on the rationale behind and the initial results from a laboratory study which aims to investigate the erosion and transport of “cohesive-like” sediment mixtures in controlled laboratory conditions. The choice of the sediments used was aimed at representing the characteristics of sewer sediment mixtures found in the field. These deposits have been found to exhibit a significant degree of cohesion not found in previously studied granular sediment beds.

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.

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.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

The Prediction of Combined Sewer Overflow Performance from Models – A Case Study

1994 ◽  
Vol 29 (1-2) ◽  
pp. 373-382 ◽  
Author(s):  
Peter D. Hedges
Keyword(s):  
Storm Events ◽  
Operating Characteristics ◽  
Combined Sewer Overflows ◽  
Model Studies ◽  
Original Proposal ◽  
Model Study ◽  
Storm Flow ◽  
Combined Sewer ◽  
The Uk ◽  
Main Programme

Hydrodynamic separators have been employed as combined sewer overflows (CSOs) in the UK since the early 1960s. Since little was known of their operating characteristics, Severn Trent Water Authority contracted Aston University to monitor the performance of a separator constructed during 1986-87 at James Bridge, Walsall, UK. Unfortunately only three overflow events were fully documented during the monitoring period, which was particularly dry. One separator was therefore artificially charged by pumping from the adjacent river to simulate storm flow conditions. A model study was not included in the original proposal, but one was established to complement the main programme since the characteristics of hydrodynamic separators were poorly understood. The arrangement of the field site is described, and the results from the monitored storm events, pump tests and model studies are summarised. Characteristics derived from the model study are combined with sewage settling velocity grading curves to predict the performance of the prototype hydrodynamic separator for one of the observed storm events. Given the limitations inherent in the sewage data used, a comparison of the predicted and observed separator efficiencies demonstrates the potential of this approach for the design and selection of CSOs for specific locations.

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

Occurrence and fate of organic pollutants in combined sewer systems and possible impacts on receiving waters

2007 ◽  
Vol 56 (10) ◽  
pp. 141-148 ◽  
Author(s):  
A. Welker
Keyword(s):  
Organic Pollutants ◽  
Wastewater Treatment Plants ◽  
Combined Sewer Overflows ◽  
Sewer Systems ◽  
Flow Surface ◽  
Combined Sewer ◽  
Polycyclic Aromatic ◽  
Receiving Waters ◽  
First Time ◽  
Receiving Water

Selected organic pollutants are classified based on an intensive literature survey. Two wastewater parameters (COD and ammonium) and six selected organic pollutants (polycyclic aromatic hydrocarbons (PAH), diethylhexylphthalate (DEHP), estradiol (E2), ethinylestradiol (EE2), ethylenediamine tetraacetic acid (EDTA) and nitrilo triaceticacid (NTA)) are specified. As a result, for the first time representative concentrations in dry weather flow, surface runoff and effluent of wastewater treatment plants (WWTPs) in combined sewer systems (CSS) are stated. The second part of the paper presents a first estimation of main emission out of a combined sewer system and possible receiving water impacts in terms of (1) annual discharged loads calculated by pollution load simulations in a hypothetical catchment and (2) concentrations calculated in combined sewer overflows (CSO) discharges and resulting receiving water concentrations.

The Actiflo method

1998 ◽  
Vol 37 (1) ◽  
pp. 269-275 ◽  
Author(s):  
Victoria Plum ◽  
Claus P. Dahl ◽  
Leif Bentsen ◽  
Carsten R. Petersen ◽  
Lis Napstjert ◽  
...  
Keyword(s):  
Pilot Plant ◽  
Treatment Method ◽  
Combined Sewer Overflows ◽  
Sewer Systems ◽  
Physico Chemical ◽  
Combined Sewer ◽  
Removal Of Heavy Metals ◽  
The Usa ◽  
Typical Treatment ◽  
Total P

The Actiflo method is a compact physico-chemical water treatment method. The method has for many years been used in waterworks for the treatment of surface water to produce drinking water, but is now to an increasing extent being used for treating wastewater and combined sewer overflows (CSO). The method works as weighted settling combined with lamella settling. Typical treatment efficiency: suspended solids 85%, COD 60%, Kjeldahl N 18% and total P 85%. The method also permits efficient removal of heavy metals. Krüger has a mobile pilot plant with a capacity of 80-120 m3/h in Scandinavia and a similar pilot plant in the USA. As an Actiflo plant can be started up in less than 15 minutes, it has many applications. Several applications may also be combined, e.g. treatment of overflows during rain and treatment of lake water in the recipient nearby in dry weather. As an alternative to detention basins in combined sewer systems the Actiflo method is often a competitive method.

Prediction of locations with sediment deposits in sewers

1996 ◽  
Vol 33 (9) ◽  
pp. 147-154 ◽  
Author(s):  
Ole Mark ◽  
Uros Cerar ◽  
Gustavo Perrusquía
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Transport Model ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
Sewer Systems ◽  
Sediment Transport Model ◽  
Sediment Deposits ◽  
Combined Sewer ◽  
Movable Bed

The present paper presents an application of MOUSE ST, a general deterministic sediment transport model for sewer systems. MOUSE ST is used to predict the locations subjected to sedimentation in the sewer system of Ljubljana, Slovenia. The prediction is made by means of a sediment transport model with a movable bed. This model is run in parallel with the hydrodynamic MOUSE model. The results, in terms of locations with sediment deposits, are compared with field data from the sewer system in Ljubljana. Further, the model is used to predict the effect of the removal of the sediment deposits on the combined sewer overflows.

Evaluation of total emissions from treatment plants and combined sewer overflows

1998 ◽  
Vol 37 (1) ◽  
pp. 333-340 ◽  
Author(s):  
Joachim Guderian ◽  
Andreas Durchschlag ◽  
Jürgen Bever
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Design Flow ◽  
Simulation Tool ◽  
Combined Sewer Overflows ◽  
Flow Management ◽  
Sewer Systems ◽  
Optimal Value ◽  
Combined Sewer

Based upon the connection of a simulation program for combined sewer systems with the IAWQ-Activated Sludge Model No.1 the new simulation tool GEMINI was developed, which allows the calculation of sewer and sewage treatment plant as a unit. Some obtained results are presented in an example. They suggest, that for every treatment plant a rate of inflow is determinable, which leads to a minimum of total emissions out of sewer and treatment plant. The optimal value of sewage treatment plant inflow in the example is distinctly greater than the design flow rate fixed in German design rules. So it is recognizable that a rigid flow management for sewer and treatment plant does not always fulfil the aim of minimization of total emissions.

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