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1
Schellart, A., R. Veldkamp, M. Klootwijk, F. Clemens, S. Tait, R. Ashley, and C. Howes. "Detailed observation and measurement of sewer sediment erosion under aerobic and anaerobic conditions." Water Science and Technology 52, no. 3 (August 1, 2005): 137–46. http://dx.doi.org/10.2166/wst.2005.0070.
Анотація:
A greater understanding of the erosion behaviour of sewer sediments is necessary in order to reliably estimate the amount and nature of the sewer sediments released from deposits in sewers and transported either to waste water treatment plants or discharged into the environment. Research has indicated that microbial activity in sediment can influence the physical release of sediment from in-pipe deposits. This paper reports on a series of erosion tests in which sewer sediments from different sewer networks are kept under different environmental conditions and their resistance to erosion is examined. The erosion tests are carried out under aerobic and anaerobic conditions and two temperatures, one representing ambient sewer temperatures and a lower temperature that significantly suppresses bacterial activity.
2
Tait, Simon J., Peter J. Rushforth, and Adrian J. Saul. "A laboratory study of the erosion and transport of cohesive-like sediment mixtures in sewers." Water Science and Technology 37, no. 1 (January 1, 1998): 163–70. http://dx.doi.org/10.2166/wst.1998.0040.
Анотація:
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.
3
Schmitt, F., and C. F. Seyfried. "Sulfate Reduction in Sewer Sediments." Water Science and Technology 25, no. 8 (April 1, 1992): 83–90. http://dx.doi.org/10.2166/wst.1992.0182.
Анотація:
The Institute of Sanitation Engineering and Waste Management of the University of Hannover made investigations on sediments in sanitary sewers. These were aimed to assess how sediments influence the sewer environment, with regard especially to water quality, gas atmosphere and corrosion progress. The sulfate reduction from sediments could be determined. It was 82 % higher than the reduction rate of biofilm. A prediction of sulfate reduction with equations from biofilm theory is possible. The biologically active sediment layer for sulfate reduction has a thickness of 5 to 7.5 cm. The sulfide formation in a large sanitary sewer in Hannover depends only on water temperature with a correlation of 91 %.
4
Crabtree, R. W., R. Ashley, and R. Gent. "Mousetrap: modelling of real sewer sediment characteristics and attached pollutants." Water Science and Technology 31, no. 7 (April 1, 1995): 43–50. http://dx.doi.org/10.2166/wst.1995.0197.
Анотація:
A dynamic, pollutograph based sewer flow quality simulation model is an essential tool to aid in the control of intermittent pollution from combined sewer overflows (CSOs). Such a model can be used in conjunction with river impact models to provide an objective methodology for the control of intermittent sewage discharges. A new component to the MOUSE package has been developed, called MOUSETRAP, which is composed of a series of deterministic modules to represent the quality of surface run-off, sediment and pollutant transport within the pipe network, and the biological and chemical reactions within the sewer system. MOUSETRAP can be used to predict sewer flow quality and, hence, CSO spill concentrations and loads over time. The results of recent research into the behaviour of sediments and associated pollutants in sewers have shown that these aspects are crucial to the development of a reliable, deterministic sewer flow quality model. MOUSETRAP, by representing the physical and chemical characteristics and behaviour of real sewer sediment types has the ability to simulate storm event pollutographs incorporating first foul flush phenomena. MOUSETRAP achieves this by representing pollutants associated with dissolved phase liquid transport and pollutants associated with sediments including bed deposits, bed load and settleable suspended solids. The results of data collection are used to characterise sewer sediments and a theoretical basis for the modelling of sediments and sediment attached pollutants in MOUSETRAP is considered. Finally, the model default values for characteristics of the surface, deposited foul flow and in-pipe sediment types in MOUSETRAP are presented.
5
Luo, Yongpeng, Shenxu Bao, Siyuan Yang, Yimin Zhang, Yang Ping, Chao Lin, and Pan Yang. "Characterization, Spatial Variation and Management Strategy of Sewer Sediments Collected from Combined Sewer System: A Case Study in Longgang District, Shenzhen." International Journal of Environmental Research and Public Health 18, no. 14 (July 20, 2021): 7687. http://dx.doi.org/10.3390/ijerph18147687.
Анотація:
In the urban drainage system, the formation of sewer sediments is inevitable, and the removal of sewer sediments is necessary for system maintenance. Disposal of arisings from sewer sediment removal is becoming a serious environmental issue. The current knowledge of sewer sediments is limited, which is restrained to sewer sediments management. To better understand this municipal waste, the sewer sediments of a combined sewer system in Longgang District, Shenzhen were collected and characterized, and the spatial distribution characteristics of contaminants were analyzed. Based on the bivariate correlation analysis, it is found that many contaminants in sewer sediments have a strong relationship with spatial variables. Compared to the sewer sediments in industrial areas, those in residential areas contain higher concentrations of Hg and phosphorus. The sediments in the sewage conduit also contain more organic matter (OM), phosphorus, Cu, and Ni, and the sediments in the rainwater conduit contain a higher concentration of Cd. Moreover, the sediments produced in different catchments also show huge differences in the content of contaminants. These spatial distribution characteristics may provide help for the further classification of sewer sediments, thereby making the disposal of sediments more targeted. According to the local standards of sludge disposal, land application and incineration are not suitable for managing sewer sediments due to the low OM content and poor lower heating value (LHV). Although sanitary landfill is feasible for sewer sediments disposal, the complicated composition of sewer sediments still poses the risk of polluting the surrounding environment. The management of sewer sediments via the production of building materials is a promising technical route that can avoid the migration of hazardous contaminants and produce valuable products. This study may improve our understanding of sewer sediments and provide a reliable recommendation for sewer sediment management.
6
Seco, I., M. Gómez Valentín, A. Schellart, and S. Tait. "Erosion resistance and behaviour of highly organic in-sewer sediment." Water Science and Technology 69, no. 3 (November 26, 2013): 672–79. http://dx.doi.org/10.2166/wst.2013.761.
Анотація:
Reliable prediction of time-varying pollutant loads in combined sewer systems during storm periods can aid better management of the release of pollution into natural environments as well as enhancing storage tank design. Better understanding of the behaviour of sewer sediments is crucial for the development of models that adequately describe the transport of in-sewer solids and accurately predict the changes in pollutant concentration within combined sewers during storm events. This paper reports on the results of a test programme to examine the erosion of highly organic sewer sediment under the application of time-varying shear stress. The tests were carried out with and without supplying oxygen, and varying simulated dry-weather periods. The aim was to investigate the behaviour of real in-sewer sediment with a high organic content (around 80%) in an attempt to improve prediction of the transport rates under the particular Mediterranean conditions of long dry-period/build-up and intense rainfall/wash-off, and understand how this environment affects the erosional resistance and subsequent sediment release. Results have been compared with previous work on lower organic content sewer sediments and artificial organic sediment.
7
Crabtree, R., H. Garsdal, R. Gent, O. Mark, and J. Dórge. "MOUSETRAP — A DETERMINISTIC SEWER FLOW QUALITY MODEL." Water Science and Technology 30, no. 1 (July 1, 1994): 107–15. http://dx.doi.org/10.2166/wst.1994.0011.
Анотація:
Recent research into the behaviour of sediments and associated pollutants in sewers has formed the foundation for a dynamic pollutograph-based sewer flow quality simulation model called MOUSETRAP. This is a new component to the MOUSE sewer system hydraulic modelling package. MOUSETRAP has been developed by an international consortium of sewer model developers and users to predict short term variations in sewer flow quality and sediment transport in response to storm events. MOUSETRAP is composed of a series of modules to represent: the quality of surface run off; sediment and pollutant transport, erosion and deposition within pipes; and the biological and chemical processes within the sewer system. By representing the current understanding of real sewer sediments, this new tool gives the user the capability to simulate storm event pollutographs incorporating first foul flush phenomena. The paper describes the basis of the new MOUSETRAP modules. Results of initial theoretical testing and pilot study applications are presented to illustrate the model's capabilities and potential for use in the management of urban wastewater discharges.
8
Ashley, R. M., D. J. J. Wotherspoon, M. J. Goodison, I. McGregor, and B. P. Coghlan. "The Deposition and Erosion of Sediments in Sewers." Water Science and Technology 26, no. 5-6 (September 1, 1992): 1283–93. http://dx.doi.org/10.2166/wst.1992.0571.
Анотація:
The problems caused by sediments in sewers are now universally acknowledged. A number of countries have set up comprehensive programmes to study all aspects of sewer sediments; their occurrence, nature and movement. In the UK the Water Research centre and others have funded a comprehensive study of the sediments in the Dundee sewer system. The rate of sedimentation and the yield strength of the sediments have been investigated and considered in terms of the subsequent erosion by increasing flows. The sediments have been found to be cohesive in nature and highly resistant to erosion in the main interceptor sewer, whereas in the trunk sewers the sediments are more granular and less cohesive in nature. A sewer classification system is suggested which is based on physical characteristics, and also relates to the nature of the sediments deposited, and the bed-load material conveyed close to the bed.
9
Tait, S. J., A. Marion, and G. Camuffo. "Effect of environmental conditions on the erosional resistance of cohesive sediment deposits in sewers." Water Science and Technology 47, no. 4 (February 1, 2003): 27–34. http://dx.doi.org/10.2166/wst.2003.0213.
Анотація:
The potential to adjust sewer network operation in order to control the level of transported sediment in sewage so as to enhance the performance of end-of-pipe treatment works is now being investigated. However for this to become a practical management option there is a need to be able to understand the processes which control the movement of sediments that are found in many combined sewers. Crucial to this understanding is an ability to predict how sediments from in-sewer deposits, are released by the action of vigorous flows. This paper reports on a laboratory investigation that aimed to investigate the effect that the environmental conditions during deposit formation can have on the ability of fine-grained organic sediment within in-sewer deposits to resist erosion and subsequent release into transport.
10
Berlamont, Jean E., and Hilde M. Torfs. "Modeling (partly) cohesive sediment transport in sewer systems." Water Science and Technology 33, no. 9 (April 1, 1996): 171–78. http://dx.doi.org/10.2166/wst.1996.0204.
Анотація:
Although the basic mechanisms of sediment transport in sewers are the same as in rivers, it is not necessarily appropriate to use the many models that have been developed for sediment transport in rivers also in sewers. Different reasons are: 1) sewer sediments are often mixtures of cohesive and non cohesive material, and the bed is often stratified; 2) due to consolidation of the (partly cohesive) bed material, the erosion resistance of the bed may vary with time; 3) the flow conditions in sewers are usually unsteady, which is not accounted for in the classical sediment transport models; 4) existing models have been derived from experiments in rectangular flumes: the results are not directly applicable to sewers with circular cross section where the distribution of bed shear stress may be completely different from a rectangular section; 5) the limited availability of erodible material and the varying supply of sediments add additional difficulty to the modelling of sediment transport in sewers.
11
Blaszczyk, Pawel, and Richard M. Ashley. "Application of new criteria to control sediment problems in combined sewers in Poland." Water Science and Technology 33, no. 9 (April 1, 1996): 245–52. http://dx.doi.org/10.2166/wst.1996.0222.
Анотація:
The Polish criteria for design and operation to control sediments in combined sewers may now be replaced to reflect new knowledge. A series of field investigations have been carried out to examine the occurrence and nature of sediments in sewers in Warsaw. Using the results of these studies and new UK approaches to the control of sedimentation in sewers, new simplified criteria have been defined based on different modes of sediment transport and relative sewer sizes.
12
Ashley, R. M., D. J. J. Wotherspoon, B. P. Coghlan, and I. McGregor. "The Erosion and Movement of Sediments and Associated Pollutants in Combined Sewers." Water Science and Technology 25, no. 8 (April 1, 1992): 101–14. http://dx.doi.org/10.2166/wst.1992.0184.
Анотація:
The complex and inhomogeneous nature of sediments in sewers, and the variability of the particles and dissolved substances flowing in dry and wet weather combined sewage, make the prediction of sediment erosion and pollutant release a difficult proposition. It is apparent that the erosion of sediments in sewers can release pollutants in concentrations which exceed by many times the levels found in the various contributing sources of the sediments and pollutants, and whilst this release is normally in the form of an initial highly polluting foul flush at the start of wet weather flow, the occurrence of foul flushes has not been found to be ubiquitous, even from event to event in the same sewer. The origins of foul flushes may be attributable to the speedy erosion of a weak layer of highly concentrated surficial sediments (or bed-load) at the start of wet weather flows. Various models have been proposed, and some successfully applied to field data, to simulate the erosion and movement of sediments and associated pollutants in combined sewer systems.
13
Gent, Rebecca, Bob Crabtree, and Richard Ashley. "A review of model development based on sewer sediments research in the UK." Water Science and Technology 33, no. 9 (April 1, 1996): 1–7. http://dx.doi.org/10.2166/wst.1996.0162.
Анотація:
A major programme of research into the nature, behaviour and occurrence of sediment deposits associated with sewer systems has been carried out in the UK since 1988. This research has been co-ordinated by the UK water industry's Urban Pollution Management Programme. The main driving force behind this research has been the need to collect fundamental data to support the development of sewer flow quality simulation models. Research results have significantly enhanced knowledge pertaining to sewer sediments and this has proved to be crucial to the development of reliable modelling tools to predict the quality of sewer system discharges. Particular advances have been made in the ability to understand and represent the effects of sewer sediment rheology and the attachment of pollutants to sediments. Many performance limitations of current models, such as MOSQITO and MOUSE TRAP, can be related to the modelling of sewer sediments. User requirements for the next generation of models will only be met if sewer sediments research results are fully utilised and further research can be tailored to meet end user driven modelling requirements. This paper reviews the results and applications of sewer sediments research in the UK and identifies additional research required to support further model development.
14
McGregor, Iain, Nicola H. Souter, and Richard M. Ashley. "Sewer sediments: preparation methods for enumerating bacteria." Water Science and Technology 33, no. 9 (April 1, 1996): 179–86. http://dx.doi.org/10.2166/wst.1996.0206.
Анотація:
In the UK, the Urban Pollution Management programme has contributed to extensive international research concerning solids associated with urban drainage systems. Since 1986, as part of the UPM programme, research undertaken at the Wastewater Technology Centre, University of Abertay Dundee, has focused primarily upon the characteristics and movement of solids and associated pollutants in combined sewer systems. These investigations have considered the behaviour of sediments and their attached pollutants during dry weather and storm flow conditions, and also the degree of pollutants associated with, and released from sewer sediments during periods of increasing sediment bed shear stresses. Data collection and sample analysis were driven by requirements specified for the development of a United Kingdom sewer flow model termed “MOSQITO”, with the basic chemical parameters ie; COD, BOD and ammonia, of sewage and sewer sediments. A data collection programme is described which assesses the feasibility of using combined sewer sediment preparation protocols, normally used for these chemical analyses, to enumerate bacterial indicator organisms present in deposited sediments. The data were analysed to investigate whether the methods used were precise in terms of repeatability, prior to more extensive studies being undertaken to provide sewer sediment data for bacterial numbers.
15
Vollertsen, Jes, Thorkild Hvitved-Jacobsen, Iain McGregor, and Richard Ashley. "Aerobic microbial transformations of pipe and silt trap sediments from combined sewers." Water Science and Technology 38, no. 10 (November 1, 1998): 249–56. http://dx.doi.org/10.2166/wst.1998.0408.
Анотація:
A conceptual model for wastewater quality changes during transport in sewers is presented. The model concept includes reaeration and main aerobic and anaerobic microbial processes in water phase and sewer biofilm. Emphasis is on microbial transformations of heterotrophic biomass and soluble and particulate fractions of organic substrate; the inclusion of sulfate respiration in the model concept is outlined. The model concept has been tested in gravity sewers as well as in pressure mains. Oxygen utilization rate measurements of wastewater samples from sewers are used for model calibration. The model is exemplified as a tool for evaluation of wastewater quality changes in an intercepting gravity sewer. The model concept can be used in the design process of sewers taking into account quality aspects. It is recommended to consider sewer processes when addressing functioning of the sewer, wastewater treatment and combined sewer overflow effects.
16
Buxton, A., S. Tait, V. Stovin, and A. Saul. "Developments in a methodology for the design of engineered invert traps in combined sewer systems." Water Science and Technology 45, no. 7 (April 1, 2002): 133–42. http://dx.doi.org/10.2166/wst.2002.0125.
Анотація:
Sediments within sewers can have a significant effect on the operation of the sewer system and on the surrounding natural and urban environment. One possible method for the management of sewer sediments is the use of slotted invert traps. Although invert traps can be used to selectively trap only inorganic bedload material, little is known with regard to the design of these structures. This paper presents results from a laboratory investigation comparing the trapping performance of three slot size configurations of a laboratory-scale invert trap. The paper also presents comparative results from a two-dimensional computational model utilising stochastic particle tracking. This investigation shows that particle tracking consistently over-predicts sediment retention efficiencies observed within the laboratory model.
17
Xu, Zuxin, Jun Wu, Huaizheng Li, Zhenghua Liu, Keli Chen, Hao Chen, and Lijun Xiong. "Different erosion characteristics of sediment deposits in combined and storm sewers." Water Science and Technology 75, no. 8 (February 8, 2017): 1922–31. http://dx.doi.org/10.2166/wst.2017.076.
Анотація:
To investigate the different erosion patterns of sediments in combined and storm sewers, sediments from three separate sewer systems and two combined sewer systems in urban Shanghai were collected for the flushing experiments. These experiments were conducted with different consolidation periods and shear velocities. As the consolidation period increases, dissolved oxygen exhibits a positive effect on the microbial transformations of organic substrates. Potential structural changes and separations of the surface and bottom layers of sediments are observed. The results also reveal that the organic matter, particle size and moisture have different effects on the erosion resistance of sediments. Furthermore, illicit connections behaved as an important factor affecting the viscosity and static friction force of particles, which directly alter the erosion resistance of sewer sediments.
18
Sakrabani, R., R. M. Ashley, and J. Vollertsen. "The influence of biodegradability of sewer solids for the management of CSOs." Water Science and Technology 51, no. 2 (January 1, 2005): 89–97. http://dx.doi.org/10.2166/wst.2005.0036.
Анотація:
The re-suspension of sediments in combined sewers and the associated pollutants into the bulk water during wet weather flows can cause pollutants to be carried further downstream to receiving waters or discharged via Combined Sewer Overflows (CSO). A typical pollutograph shows the trend of released bulk pollutants with time but does not consider information on the biodegradability of these pollutants. A new prediction methodology based on Oxygen Utilisation Rate (respirometric method) and Erosionmeter (laboratory device replicating in-sewer erosion) experiments is proposed which is able to predict the trends in biodegradability during in-sewer sediment erosion in wet weather conditions. The proposed new prediction methodology is also based on COD fractionation techniques.
19
McGregor, I., R. M. Ashley, and K. O. K. Oduyemi. "Pollutant Release from Sediments in Sewer Systems and Their Potential for Release into Receiving Waters." Water Science and Technology 28, no. 8-9 (October 1, 1993): 161–69. http://dx.doi.org/10.2166/wst.1993.0614.
Анотація:
A programme of work funded by the UK Water Research Centre (WRc) has been carried out to investigate the nature, occurrence and re-entrainment into the sewage flow of sewer sediments and their associated pollutants to provide data for the development of UK sewer flow quality models, MOSQITO and MOUSETRAP. Methodologies for the preparation of sewer sediment samples prior to chemical analysis are described. These methods have been developed to determine the level of pollutants released from sewer sediments which will be representative of the conditions found in the sewer environment. Application of progressively lower shear stresses to samples of sediment, from an extreme, via blending, to less severe preparative methods by means of a stirring technique, fractionate sediment samples so that the polluting potential may be assessed separately for both dissolved and resuspendable phases. Stirring preparative methods release less pollutants from a sediment sample than from the blending procedures, with the level of pollutant release being dependent upon the shear stress being applied to the sample, with higher shear values releasing as would be expected, more pollutants.
20
Ristenpart, E., R. M. Ashley, and M. Uhl. "Organic near-bed fluid and particulate transport in combined sewers." Water Science and Technology 31, no. 7 (April 1, 1995): 61–68. http://dx.doi.org/10.2166/wst.1995.0201.
Анотація:
Studies in Germany, Belgium, France and Scotland have revealed that there are significant solids transport gradients in the depth of foul and combined sewage flows. Continuous field observations of changes in depths of sediment deposits in combined sewers have also indicated that there is an interaction between the erosion and deposition processes and changes in the mass transport of solids in regions in the overlying flow. A fuller understanding of the interactive phenomena is essential for both sewer sediment management and the minimization of associated pollution from wash-out of solids via CSOs. The paper presents results from the detailed studies in Hildesheim, Germany and those carried out in Dundee, Scotland, investigating the heterogeneity of solids movement with regard to gross solids, erosion of sewer sediments and their interactions with the suspended transport phases and the layer of very dense fluid found to be transported under certain circumstances, near the sediment bed or sewer invert (traditionally called ‘bed-load’).
21
Arthur, S., and R. M. Ashley. "The influence of near bed solids transport on first foul flush in combined sewers." Water Science and Technology 37, no. 1 (January 1, 1998): 131–38. http://dx.doi.org/10.2166/wst.1998.0032.
Анотація:
The problems associated with deposited sediments in sewers, and their transport through sewer systems have been the subject of detailed fieldwork programmes in the UK, and elsewhere in Europe. Existing laboratory, and some field based research exercises have focused on the relatively small, discrete particles. It is clear, however, that combined sewer systems have inputs which comprise of a significant proportion of large organic solids (faecal and food wastes), as well as the finer range of particle sizes. The increased concern regarding CSO spills into the environment has fuelled the recent development of sewer flow quality models, such as HYDROWORKS QM and MOUSETRAP, some of which make no attempt to represent the transport of these larger organic particles. Herein, the results of a collaborative research programme undertaken between three UK universities and a water authority are discussed. Transport at the bed in sewers, as “near bed solids”, is defined. Based on a comprehensive data collection program undertaken in the Dundee combined sewerage system, a method is presented which may be used to estimate the rate of sediment transport near the bed in sewers. The influence that solids in transport near the bed have on first foul flush in combined sewers is discussed. A methodology is proposed which may be used to estimate the extent to which sediment in transport near the bed in sewers contributes to first foul flush phenomena, by describing the movement of a storm wave along a conceptual sewer length.
22
Kleijwegt, Rob A., Robin G. Veldkamp, and Chandra Nalluri. "Sediment in Sewers: Initiation of Transport." Water Science and Technology 22, no. 10-11 (October 1, 1990): 239–46. http://dx.doi.org/10.2166/wst.1990.0310.
Анотація:
The initiation of sediment transport in sewers was investigated in field and laboratory studies. From the field studies it was concluded that some deposits in sewers are permanent due to the insufficient capability of the flow to erode the deposits. From the laboratory studies it was concluded that the upper limit of the critical shear stresses for cohesive sewer sediments may not exceed 5-7 N/m2. Non-cohesive sediments are eroded at lower shear stresses than predicted by Shields' criterion. The shear stresses were calculated using the general equations of continuity and motion and Einstein's separation technique for channels of compound roughness. Experiments showed the validity of this method.
23
Moojong, Park, Jun Hwandon, and Shin Minchul. "Estimation of sediments in urban drainage areas and relation analysis between sediments and inundation risk using GIS." Water Science and Technology 58, no. 4 (September 1, 2008): 811–17. http://dx.doi.org/10.2166/wst.2008.283.
Анотація:
Sediments entering the sewer in urban areas reduce the conveyance in sewer pipes, which increases inundation risk. To estimate sediment yields, individual landuse areas in each sub-basin should be obtained. However, because of the complex nature of an urban area, this is almost impossible to obtain manually. Thus, a methodology to obtain individual landuse areas for each sub-basin has been suggested for estimating sediment yields. Using GIS, an urban area is divided into sub-basins with respect to the sewer layout, with the area of individual landuse estimated for each sub-basin. The sediment yield per unit area for each sub-basin is then calculated. The suggested method was applied to the GunJa basin in Seoul. For a relation analysis between sediments and inundation risk, sub-basins were ordered by the sediment yields per unit area and compared with historical inundation areas. From this analysis, sub-basins with higher order were found to match the historical inundation areas.
24
Bertrand-Krajewski, J. L., J. P. Bardin, and C. Gibello. "Long term monitoring of sewer sediment accumulation and flushing experiments in a man-entry sewer." Water Science and Technology 54, no. 6-7 (September 1, 2006): 109–17. http://dx.doi.org/10.2166/wst.2006.619.
Анотація:
This paper presents continuous field experiments carried out during 4 years in a man-entry egg-shaped combined sewer in Lyon, France in order to contribute to the knowledge and the modelling of sediment accumulation and sediment removal by means of a Hydrass flushing gate. The 250 μm sediments are mainly mineral, and their physical and chemical characteristics appear as rather stable in time and space. Long-term sediment monitoring reveals: i) a regular asymptotic increase of both the sediment mass and the slope of its longitudinal profile, ii) a clear correlation between local sediment profile irregularities and sewer ancillaries but without significant influence on the global and long term accumulation. Simple sediment accumulation modelling shows: i) a good suitability of a three parameters conceptual model to reproduce asymptotic sediment volume accumulation, and ii) a good suitability of the Velikanov model to reproduce sediment profiles. Both models reproduce observations with an acceptable margin of uncertainty for operational management purposes but are very sensitive to input data and parameter values. The Hydrass flushing gate is efficient and it appeared that the mass of sediments moves downstream linearly with the number of flushes.
25
Beichert, J. "Influence of Sewer Sediments on the Overflow Load for Various Combined Sewer Systems." Water Science and Technology 25, no. 8 (April 1, 1992): 217–24. http://dx.doi.org/10.2166/wst.1992.0196.
Анотація:
The influence of various characteristics of combined sewer systems on the overflow load has been analysed by means of long-term simulation. Special attention was paid to the sewer sediment. A simulation model that has been developed for this purpose comprises an approach for the sediment transport. This approach has been calibrated by means of various values of pilot plants. It has been demonstrated that the importance of the first flush is dependent on the bottom slope. The ‘dry weather balance' has been defined as a parameter which allows the determination of the overflow load from sewer sediments.
26
May, Richard W. P., John C. Ackers, David Butler, and Siân John. "Development of design methodology for self-cleansing sewers." Water Science and Technology 33, no. 9 (April 1, 1996): 195–205. http://dx.doi.org/10.2166/wst.1996.0210.
Анотація:
New guidelines for the design of self-cleansing sewers have been developed in a recently completed CIRIA research project. Laboratory and field studies were reviewed and compared, and appropriate equations were selected for predicting sediment movement in pipes. Self-cleansing performance was defined in terms of three design criteria covering the transport of fine-grained materials in suspension, the transport of coarser sediments as bed load, and the erosion of cohesive deposits. Information on typical sediment characteristics in UK sewers was reviewed and used to produce guidelines on values of minimum flow velocity and pipe gradient for different types and sizes of sewer.
27
Luyckx, G., G. Vaes, and J. Berlamont. "Solids separation efficiency of combined sewer overflows." Water Science and Technology 51, no. 2 (January 1, 2005): 71–78. http://dx.doi.org/10.2166/wst.2005.0034.
Анотація:
The removal of sewer solids at combined sewer overflow locations depends on the flow patterns inside the overflow structure on the one hand and on the sediment characteristics on the other hand. Flow conditions can be described by the residence time distribution; sewer sediments can be characterised by their settling velocity distribution. The combination of both distributions leads to a dimensionless efficiency curve, which gives the removal efficiency as a function of the Hazen number. For field conditions this efficiency curve is mainly influenced by the settling velocity distribution of the sewer sediments and, as a consequence, nearly identical efficiency curves are found for different types of prototype CSO structure. For design purposes, a methodology using return frequency analysis is proposed.
28
Laplace, D., Y. Sanchez, D. Dartus, and A. Bachoc. "Sediment Movement into the Combined Trunk Sewer No. 13 in Marseille." Water Science and Technology 22, no. 10-11 (October 1, 1990): 259–66. http://dx.doi.org/10.2166/wst.1990.0312.
Анотація:
The AGHTM, a French technical association, supports a research program on the transfer of solids into sewer networks. It aims to better understand how sediments develop in trunk sewers and what can be their contribution to wet-weather pollutant discharges. The priority is given, during the first phase, to observation, especially inside the combined trunk sewer n° 13 in Marseille. Various parameters such as sediment depth, water level, flow velocity fields, sediment particle size or mechanical characteristics are measured. Certain conclusions have been reached. For example, we have been led to form some assumptions, such as: – the volume of sediment increases substantially, principally at the entry points, during the first rainfall events, it decreases during the three days following rain, and seem to become stable after several months; – the solids deposited in the sediment are much larger than those which make up the most part of pollutant discharge during wet weather.
29
Gasperi, J., V. Rocher, T. Celaudon, R. Moilleron, and G. Chebbo. "Hydrocarbons and heavy metals fixed to the lift station sediment of the Paris combined sewer network." Water Science and Technology 52, no. 3 (August 1, 2005): 119–27. http://dx.doi.org/10.2166/wst.2005.0068.
Анотація:
This work aims to characterise the pollutant loads fixed to the Lift Station (LS) sediments. Firstly, levels of n-alkanes, PAH and heavy metals (Fe, Zn, Cu, Pb and Cd) of LS sediments were assessed, and were found of the same order of magnitude as those reported for street runoff. In addition, investigations on LS sediment reveal that n-alkane distributions reflect the combination of biologic and petrogenic inputs, while PAH distributions indicate a major pyrolytic origin with traces of petrogenic contaminations. The metallic fingerprints also attest to the important contribution of road traffic emissions. Secondly, a comparison between LS sediment and the Gross Bed Sediment (GBS) pollutant contamination was established in order to optimize the in-sewer deposits management. For hydrocarbons, a similar contamination between both sediments is found. For the heavy metals, this comparison indicates a similar Fe and Zn content, while Pb, Cu and Cd contents differ. Indeed, LS sediment shows a higher Cu content, linked to the occurrence of intensive brake lining abrasion, compared with GBS, which reflects a higher Pb and Cd content, owing to the contribution of roof runoff. This result reveals the impact of specific inputs such as road traffic or roof runoff on the in-sewer sediments contamination, and provides a complete overview of the LS sediment contamination. This database could be used by the municipality to optimize their contaminated in-sewer sediment management.
30
McIlhatton, T. D., R. M. Ashley, and S. J. Tait. "Improved formulations for rapid erosion of diverse solids in combined sewers." Water Science and Technology 52, no. 5 (September 1, 2005): 143–50. http://dx.doi.org/10.2166/wst.2005.0128.
Анотація:
For more than a decade, research carried out in Scotland has investigated the movement of sediment in sewers and the associated pollutant release. Pollution by discharges from combined sewer overflows can adversely affect watercourses, particularly those in urban areas. Solids and dissolved contaminants, many derived from in-sewer deposits during a storm event, can be especially significant. This phenomenon can occur during events known as ‘foul flushes’. In combined sewers these typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants is significantly higher than at other times. It has become apparent that much of the suspended load originates from solids eroded from the bed. The ‘near bed solids’ which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. This paper describes some of the methods employed to investigate the solids eroding in combined sewers during peak flow events. The work examined the potential for sediment re-suspension under high flow conditions both in the laboratory and in the field.
31
Xanthopoulos, C., and A. Augustin. "Input and Characterization of Sediments in Urban Sewer Systems." Water Science and Technology 25, no. 8 (April 1, 1992): 21–28. http://dx.doi.org/10.2166/wst.1992.0175.
Анотація:
This paper discusses informative data on the particle size distribution in sewer sediments including data on the contamination of the individual fractions with micropollutants. For this purpose, two low-gradient sewer systems, a combined and a separate system, were sampled. This paper will show the differences between the two systems' sediments characteristics. Furthermore the sewer sediments will be compared to settleable solids introduced by street runoff into the sewer system and deposits found in a detention basin of the combined sewage. Finally, we will propose a simplified analysis method based on the observed data to describe the cohesivity of the sewer sediments.
32
Zhang, Ziyang, Kun Li, Xiaoran Zhang, and Haiyan Li. "The characteristics of dissolved organic matter (DOM) in storm sewer sediments and the binding interaction with Cu(II) in four typical regions in Beijing, China." Water Science and Technology 76, no. 1 (March 30, 2017): 155–63. http://dx.doi.org/10.2166/wst.2017.191.
Анотація:
In this work, dissolved organic matter (DOM) was extracted from storm sewer sediments collected in four typical regions (residential, campus, traffic and business regions) in Beijing, China. The basic characteristics of DOM were analyzed by UV–visible spectroscopy (UV–Vis), excitation-emission matrix Fluorescence Spectroscopy and Fourier Transform Infrared Spectroscopy. Furthermore, the complexation between DOM and Cu(II) were investigated. The results showed that there were large amount of aromatic structure in the DOM extracted from storm sewer sediments. The microbial activities had also made a contribution to the DOM in storm sewer sediments. The composition of DOM influenced the complexing capacity of Cu(II) greatly, which may be attributed to the protein-like and humic-like substances in storm sewer sediments. This study demonstrated valuable information on the structure present in the DOM of storm sewer sediments and provided new insight for exploring the relationship between DOM and co-existing heavy metals in storm sewer sediments.
33
Banasiak, Robert. "Hydraulic performance of sewer pipes with deposited sediments." Water Science and Technology 57, no. 11 (June 1, 2008): 1743–48. http://dx.doi.org/10.2166/wst.2008.287.
Анотація:
This paper investigates in-sewer sediment deposit behaviour and its influence on the hydraulic performance of sewer pipes. This evaluation is based on experimental results regarding the mobility of non-cohesive and partly cohesive deposits in a partially full circular pipe. The focus of these tests is on the development of bed forms and friction characteristics. In particular, it is investigated to what extent the bed forms from the non-cohesive and (partly) cohesive sediments affect a sewer's discharge capacity. Based on the laboratory study results and on the existing criteria for sewer design, a generic assessment of a sewer's hydraulic performance is made. The relative discharge factor for a pipe with sediment deposit is analysed in terms of the thickness and roughness of the deposit.
34
Faram, M. G., and R. Harwood. "A method for the numerical assessment of sediment interceptors." Water Science and Technology 47, no. 4 (February 1, 2003): 167–74. http://dx.doi.org/10.2166/wst.2003.0246.
Анотація:
The problems associated with the presence of sediments in sewers and stormwater drainage systems represent a major engineering challenge. Their accumulation can result in operational difficulties, including flow restriction and premature overflows. Sediments themselves are known to contribute significantly to the polluting load of storm overflows. The use of sediment interceptors within sewer systems or downstream of stormwater intakes represents one way of alleviating these problems. A study of stormwater sediment interceptors using Computational Fluid Dynamics (CFD) has identified that the ability of a chamber to retain, as well as remove, sediments is an important performance characteristic. A methodology for the assessment of such characteristics using CFD is presented in the context of a study of different chamber types. This concludes that primitive chambers, for example, gully pots, are likely to be far more prone to flushing out during high flow inputs than advanced systems such as vortex separators.
35
Ashley, R. M., S. J. Tait, V. R. Stovin, R. Burrows, A. Fraser, A. P. Buxton, D. J. Blackwood, A. J. Saul, and J. R. Blanksby. "The utilisation of engineered invert traps in the management of near bed solids in sewer networks." Water Science and Technology 47, no. 4 (February 1, 2003): 137–48. http://dx.doi.org/10.2166/wst.2003.0239.
Анотація:
Large existing sewers are considerable assets which wastewater utilities will require to operate for the foreseeable future to maintain health and the quality of life in cities. Despite their existence for more than a century there is surprisingly little guidance available to manage these systems to minimise problems associated with in-sewer solids. A joint study has been undertaken in the UK, to refine and utilise new knowledge gained from field data, laboratory results and Computational Fluid Dynamics (CFD) simulations to devise cost beneficial engineering tools for the application of small invert traps to localise the deposition of sediments in sewers at accessible points for collection. New guidance has been produced for trap siting and this has been linked to a risk-cost-effectiveness assessment procedure to enable system operators to approach in-sewer sediment management pro-actively rather than reactively as currently happens.
36
Hvitved-Jacobsen, T., J. Vollertsen, and N. Tanaka. "Wastewater quality changes during transport in sewers – an integrated aerobic and anaerobic model concept for carbon and sulfur microbial transformations." Water Science and Technology 38, no. 10 (November 1, 1998): 257–64. http://dx.doi.org/10.2166/wst.1998.0409.
Анотація:
Organic matter in sediments from pipes and silt traps in combined sewers was divided into fractions with different settling velocities. Biodegradability of organic matter for these fractions was characterised based on results from a conceptual model of aerobic transformations of resuspended sediments calibrated on oxygen utilisation rates. Pipe sediments as well as silt trap sediments were investigated and no differences between these deposits were detected. It was found that the largest fraction of organic matter is associated with material which settles relatively fast and only a small part is associated with relatively slow settling material. However, the fast settling organic matter was found to be rather slowly biodegradable compared to the slow settling organic fraction. Because the biodegradability of the organic matter discharged during combined sewer overflow (CSO) events is of significant importance to the impact on the dissolved oxygen concentrations in receiving waters, the biodegradability of sewer sediments is argued to be taken into account for detailed characterisation when dealing with CSO impacts.
37
Vollertsen, Jes, Thorkild Hvitved-Jacobsen, Iain McGregor, and Richard Ashley. "Aerobic microbial transformations of pipe and silt trap sediments from combined sewers." Water Science and Technology 39, no. 2 (January 1, 1999): 233–49. http://dx.doi.org/10.2166/wst.1999.0123.
Анотація:
Organic matter in sediments from pipes and silt traps in combined sewers was divided into fractions with different settling velocities. Biodegradability of organic matter for these fractions was characterised based on results from a conceptual model of aerobic transformations of resuspended sediments calibrated on oxygen utilisation rates. Pipe sediments as well as silt trap sediments were investigated and no differences between these deposits were detected. It was found that the largest fraction of organic matter is associated with material which settles relatively fast and only a small part is associated with relatively slow settling material. However, the fast settling organic matter was found to be rather slowly biodegradable compared to the slow settling organic fraction. Because the biodegradability of the organic matter discharged during combined sewer overflow (CSO) events is of significant importance to the impact on the dissolved oxygen concentrations in receiving waters, the biodegradability of sewer sediments is argued to be taken into account for detailed characterisation when dealing with CSO impacts.
38
Bong, Charles H. J. "A Review on the Self-Cleansing Design Criteria for Sewer System." Journal of Civil Engineering, Science and Technology 5, no. 2 (September 1, 2014): 1–7. http://dx.doi.org/10.33736/jcest.132.2014.
Анотація:
Sediment deposits in sewer system had been known to have adverse effects on the hydraulic performance of the system and also on the environment. Thus, the need for sewer system to carry sediment has been recognized for many years and self-cleansing criteria have been proposed in the literature for design purposes. Conventionally, a minimum critical velocity or critical shear stress was specified and although this approach had been successful in many cases; it was appreciated that a minimum critical velocity or critical shear stress which is unrelated to the characteristics and concentration of the sediment or the hydraulic behavior of the sewer could not properly represent the ability of the sewer flows to transport sediments. A more viable approach for self-cleansing design is to incorporate some aspect of the sediment and sewer characteristics into the design criteria; hence, various self-cleansing design criteria for sewer have been proposed in the literature. This paper presents a review on the various self-cleansing design criteria for sewer and proposed some further studies that could be conducted to improve the existing self-cleansing design criteria.
39
Goodison, M. J., and R. M. Ashley. "Sediment Movement in Combined Sewers in Dundee." Water Science and Technology 22, no. 10-11 (October 1, 1990): 283–86. http://dx.doi.org/10.2166/wst.1990.0317.
Анотація:
An integrated programme of work is underway in Dundee to formulate engineering strategies to alleviate the flooding in the city centre and also to minimise the continuing maintenance costs for sewer sediment removal. The objectives of this programme are commensurate with current UK research initiatives which are investigating the nature and movement of sewer sediments and associated pollution. As a consequence the studies in Dundee are providing data to assist in the development of new models for sewer flow quality.
40
Brownbill, V. R., D. H. Jackson, and I. Douglas. "Contribution of Combined Sewer Overflow-Derived Sediments to Annual Participate Load and Oxygen Demand in the River Roch, England." Water Science and Technology 25, no. 8 (April 1, 1992): 199–206. http://dx.doi.org/10.2166/wst.1992.0194.
Анотація:
The nature and behaviour of sediments released from a Combined Sewer Overflow (CSO) and their impact on the steep, gravel-bedded River Roch in northwest England were monitored by sampling suspended and bedload sediments, and by analysis of bed material. CSO-derived suspended sediments characteristically had 103 478 mg kg−1 wet weight COD, and 17 536 mg kg−1 wet weight BOD, respectively 1.1 and 3.5 times those of river suspended sediments. However, over a two-year monitoring period, overflows accounted for only 0.3% of the river water discharge, and 2.0% of the river sediment load. The CSO sediment-related BOD was only 3.5 to 7% of the river's natural sediment-related BOD in the two study years, while CSO derived COD and ammonia accounted for only 3% and 0.5% of the river pollutant loads. Under certain hydraulic conditions during storm events, sediment-BOD from the CSO could account for 60% of the river's instantaneous BOD load. However, the only high sewer-derived sediment oxygen demands occurred during storm events. No lagged impacts on dissolved oxygen were observed. In this naturally turbulent, welloxygenated river, sediments suspended in overflow liquor have a short-lived impact on DO levels, but they are too fine to settle out in the first kilometre downstream. This welldesigned, new, CSO has a minimal impact on the stream.
41
Verbanck, M. "Field Investigations on Sediment Occurrence and Behaviour in Brussels Combined Sewers." Water Science and Technology 25, no. 8 (April 1, 1992): 71–82. http://dx.doi.org/10.2166/wst.1992.0181.
Анотація:
Although sewer sediments are now widely recognized as a major source of misfunction of urban drainage systems (for both hydraulic and environmental considerations), it is still too infrequent that priority of research activities in this area is given to field studies. The measuring campaigns conducted since 1986 in the drainage system of Brussels-North have been focused on sedimentation processes in the major sewer lines. There is an obvious distinction to be made between solids constituting the sediment bed of a man-entry sewer, which are relevant for its hydraulic capacity, and the ones contributing to the pollutional impact of CSOs upon receiving waters. The material which is removed several times a year from the main trunk sewer of Brussels is coarse, granular and has a low environmental impact, notably because of its limited mobility. This appears to be due to a very efficient granulometric grading, as a result firstly of the retention of the coarsest solids in highly selective gully-pot inlets, and secondly of an elutriation process removing from the sediment bed all fine organic-rich particles during daily peak flows. There is evidence to show that the build-up of the sediment bed in these large-sized sewers is driven by a bed-load process (active even during dry spells), while the solid material responsible for the detrimental effects of CSOs (which is much finer) is primarily transported through wash-load and suspended-load.
42
Fraser, Alasdair G., Richard M. Ashley, Morven M. Sutherland, and Jes Vollertsen. "Sewer solids management using invert traps." Water Science and Technology 37, no. 1 (January 1, 1998): 139–46. http://dx.doi.org/10.2166/wst.1998.0034.
Анотація:
During the 20th century, the once common practice of trapping sewer sediments at key locations within sewerage systems has lost favour with UK sewerage designers and, to a lesser extent, operators. The reasons for this include the perception of a priori unquantifiable maintenance, and the difficulties of sewer sediment extraction in town centres in an environmentally acceptable fashion. In order to assess the need for and requirements of such trapping systems, a survey of UK sewerage operators was carried out. The results of this survey have been used as a starting point to initiate the development of a design and operational methodology for the utilisation of traps. The survey highlighted the lack of guidance available and the importance of trap monitoring to enhance performance. A fill rate model is proposed for the design and operational aspects of cleaning and monitoring traps, using two of the most recently developed “near bed solids” transport equations. The model has been applied to a trap situated on a trunk sewer in the city centre area of Dundee. The pollution potential of trap and in-pipe sediments has also been assessed by considering the biodegradability of the sediment fractions likely to be released into the flow column during storm events.
43
Hvitved-Jacobsen, T., J. Vollertsen, and P. H. Nielsen. "A process and model concept for microbial wastewater transformations in gravity sewers." Water Science and Technology 37, no. 1 (January 1, 1998): 233–41. http://dx.doi.org/10.2166/wst.1998.0056.
Анотація:
A fundamental and conceptual description of the microbial system in sewers in terms of wastewater organic matter transformations is presented. The description is examplified being under gravity sewer conditions and a conceptual model including main aerobic transformations is shown. The conceptual model of the microbial system basically agrees with the activated sludge model, (Henze et al., 1987). The model can be extended, e.g. to include anaerobic processes and processes taking place in resuspended sewer sediments under aerobic conditions. The concept for modelling transformations of wastewater during transport in sewers is recommended as the basis for further development.
44
Ruan, Mingchaun, and Jan B. M. Wiggers. "Application of time-series analysis to urban storm drainage." Water Science and Technology 36, no. 5 (September 1, 1997): 125–31. http://dx.doi.org/10.2166/wst.1997.0180.
Анотація:
In urban storm drainage, deterministic models, such as SWMM, HydroWorks and MOUSE are commonly used. However, comprehensive research programmes, including field surveys, have indicated that most processes related to urban storm drainage have stochastic characteristic, like the occurrence of rainfall events, the processes of rainfall-runoff and flow routing in sewer networks3etc.. Particularly, sediments found in sewers either in suspension or in deposition, cannot be considered as having a unique entity. Inhomogeneity and randomness are just the nature of sewer sediment behaviour. Most data required for urban storm drainage are time-series data, such as rainfall intensity, water level measured in an outfall, CSO discharge and pollutant load etc.. Consequently, time-series analysis should be an alternative for predicting some relationships of urban storm drainage, such as (net) rainfall-CSO discharge, rainfall-water level and CSO discharge-pollutant load.
45
Plihal, H., F. Kretschmer, D. Schwarz, and Th Ertl. "Innovative sewer inspection as a basis for an optimised condition-based maintenance strategy." Water Practice and Technology 9, no. 1 (March 1, 2014): 88–94. http://dx.doi.org/10.2166/wpt.2014.010.
Анотація:
Currently, around 100,000 km of public sewers are operated in Austria, with cleaning as one of the main tasks for a wastewater utility. Due to the precarious financial situation of many cities and municipalities sewer cleaning represents a considerable financial burden, resulting in the extension of cleaning intervals and the delay of required cleaning activities. Different approaches to sewer management can be distinguished. If a selective strategy is adopted, only pipe sections with deposits are cleaned. Thus, detailed information regarding the amount of deposits is required. A simple and quick method to inspect the sewer system and assess the degree of sediments is by means of a manhole-zoom camera. The current research project INNOKANIS investigates the operational condition assessment of sewers by means of different manhole-zoom cameras. So far the data suggest that the majority of investigated pipe sections belongs to the self-cleaning category. Only 1% of the pipe sections of combined sewers and 11% of sanitary sewers require additional cleaning. The example of the city of Salzburg illustrates the potential savings in connection with sewer cleaning if a selective approach is adopted. Following a strategic change, the sewer cleaning expenses decreased by 60% within a year.
46
Perrusquía, Gustavo, Ole Petersen, and Torben Larsen. "Influence of sewer sediments on flow friction and shear stress distribution." Water Science and Technology 31, no. 7 (April 1, 1995): 117–26. http://dx.doi.org/10.2166/wst.1995.0214.
Анотація:
Most sewers contain more or less deposited sediments. The paper discusses the distribution of the boundary shear stresses and the hydraulic resistance in part-full sewer pipes with such deposited sediments. The discussion is based on a series of numerical experiments using a validated numerical turbulence model. The results from the numerical model are compared with the sidewall elimination method. The validity of the sidewall elimination method is evaluated.
47
Ashley, R. M., and R. W. Crabtree. "Sediment Origins, Deposition and Build-Up in Combined Sewer Systems." Water Science and Technology 25, no. 8 (April 1, 1992): 1–12. http://dx.doi.org/10.2166/wst.1992.0173.
Анотація:
The origins of sediments and associated pollutants found in sewers are clear, and demonstrable temporal and spatial variations have been found. It is likely that these variations are such that it is not possible to formulate general rules for the rates and nature of surface wash-in to sewers. Sanitary sources, however, are more amenable to deterministic assessment. The rates of build-up of sediments in sewers vary widely, and whilst it is possible to estimate the build-up in small-sized collector sewers, no general rules are yet available to predict the rate of deposition in larger sewers. There are broad similarities in the nature of sediments found in sewers in terms of particle size and pollutant characteristics. It is possible to formulate a pragmatic taxonomy for distinct classes of these sediments in order to facilitate understanding of sediment effects and to assist engineers with developing control strategies.
48
Ashley, R. M., I. M. Longair, D. J. J. Wotherspoon, and K. Kirby. "Flow and Sediment Movement Monitoring in Large Sewers." Water Science and Technology 28, no. 11-12 (December 1, 1993): 55–65. http://dx.doi.org/10.2166/wst.1993.0646.
Анотація:
The development of more precise computer models for the simulation of the performance of sewerage systems and for management in real-time necessitates the acquisition of more precise data. Existing portable systems for the in-situ measurement of velocity in sewers as commonly used for model development have limited applicability to larger sized sewers (>1200mm). When considered together with the emerging need to monitor the behaviour of sediments in sewers, this lack of instrumentation available to observe detailed velocity gradients in the larger sewers, where sedimentation is most likely to occur, is a severe constraint. A programme of research studying sediment movements in the sewers in Dundee has led to the development of ultrasonic systems for the measurement of three dimensional velocity distributions in large sewers, and sonar systems for the monitoring of bed erosion at points within the sewer network. Data obtained from these systems has contributed to the development of a new cohesive sediment erosion model for sewers.
49
Alihosseini, Maryam, Sveinung Sægrov, and Paul Uwe Thamsen. "CFD-DEM modelling of sediment transport in sewer systems under steady and unsteady flow conditions." Water Science and Technology 80, no. 11 (December 1, 2019): 2141–47. http://dx.doi.org/10.2166/wst.2020.030.
Анотація:
Abstract Numerical and experimental investigations were undertaken to study sediment transport under steady flow conditions and under flush waves in sewer pipes. Experiments were carried out with sand and gravel of different size distributions under smooth and rough bed conditions. Moreover, different hydraulic boundary conditions were investigated for flush waves. The numerical part of this study was carried out in the computational fluid dynamics (CFD) software ANSYS Fluent, which is two-way coupled to the Discrete Element Method (DEM) software EDEM. The main focus of this study is to determine if the CFD-DEM coupled method could reasonably predict the behaviour of sediments in sewers and thus be used for studying various features of sediment transport that are not easy to determine in laboratory experiments or in-situ measurements. Furthermore, it is important to replace the traditional empirical approaches developed for fluvial conditions with new methodologies, which are able to consider the high number of variables involved in sediment transport in sewers. The numerical model was validated with laboratory experiments and used to study details of sediment transport processes in sewers.
50
Tang, Yangbo, David Z. Zhu, N. Rajaratnam, and Bert van Duin. "Experimental study of hydraulics and sediment capture efficiency in catchbasins." Water Science and Technology 74, no. 11 (September 22, 2016): 2717–26. http://dx.doi.org/10.2166/wst.2016.448.
Анотація:
Catchbasins (also known as gully pot in the UK and Australia) are used to receive surface runoff and drain the stormwater into storm sewers. The recent interest in catchbasins is to improve their effectiveness in removing sediments in stormwater. An experimental study was conducted to examine the hydraulic features and sediment capture efficiency in catchbasins, with and without a bottom sump. A sump basin is found to increase the sediment capture efficiency significantly. The effect of inlet control devices, which are commonly used to control the amount of flow into the downstream storm sewer system, is also studied. These devices will increase the water depth in the catchbasin and increase the sediment capture efficiency. Equations are developed for predicting the sediment capture efficiency in catchbasins.