Solids Transport In Sewers Research Articles

Tracking and simulation of gross solids transport in sewers

ABSTRACTInvestigation of various phenomena occurring in sewer systems is critical for increasing the sustainability of such systems. Such investigations also includes gross solids (GS) transport. GS transport may be affected by reduction of flows resulting from population decrease and/or reduced domestic water consumption. The present paper reports on the development of a model for describing GS velocity as a function of wastewater flow characteristics. The model was calibrated and validated with field experiments, in which two methods for GS tracking in sewers were developed, using small light sticks tracked by computerized light detector, and RFID based tracking. The model is integrated in a simulator which allows a description of the movement of individual GS through sewer systems. The developed model may assist in analysing existing sewer systems that are subject to changes in their input flows and prevent undesired failures (e.g. sedimentations, blockages, toxic gases) or in designing new systems.

Gross solid transport in sewers

Gross solid transport in sewers has been studied in the laboratory, by theoretical analysis, and in the field. A simplified model is proposed that can be run as an extension of existing sewer software packages (for example HydroWorks) in order to simulate the advection and deposition of solids within an entire sewer system. The model has potential applications to the engineered improvement of sewer infrastructure (including storage facilities and screening systems) and to the simulation of first flush effects and of the impact of future changes in catchment flows. A technique for tracing the physical progress of specific solids in a sewer has been developed, and has been used within an actual length in order to test the model.

Gross solid transport in sewers

Gross solid transport in sewers has been studied in the laboratory, by theoretical analysis, and in the field. A simplified model is proposed that can be run as an extension of existing sewer software packages (for example HydroWorks) in order to simulate the advection and deposition of solids within an entire sewer system. The model has potential applications to the engineered improvement of sewer infrastructure (including storage facilities and screening systems) and to the simulation of first flush effects and of the impact of future changes in catchment flows. A technique for tracing the physical progress of specific solids in a sewer has been developed, and has been used within an actual length in order to test the model.

Gross solid transport in sewers

Gross solid transport in sewers has been studied in the laboratory, by theoretical analysis, and in the field. A simplified model is proposed that can be run as an extension of existing sewer software packages (for example HydroWorks) in order to simulate the advection and deposition of solids within an entire sewer system. The model has potential applications to the engineered improvement of sewer infrastructure (including storage facilities and screening systems) and to the simulation of first flush effects and of the impact of future changes in catchment flows. A technique for tracing the physical progress of specific solids in a sewer has been developed, and has been used within an actual length in order to test the model.

Computing near-bed solids transport in sewers and similar sediment-carrying open-channel flows

Near-bed solids (NBS) in sewers are known to convey a large part of the particulate polluting material and to introduce serious bias in sewer flow quality modelling when their existence is not properly acknowledged. It is proposed that a suspended-load approach should be used to characterize this material and the related flow pattern. A two-layer suspension model (proposed as an alternative to the classical Rouse equation) is applied to combined sewer flows displaying a NBS pattern, but also to capacity suspension flows carefully controlled under laboratory conditions. Both applications are conclusive and stress the importance of a good knowledge of particle settling velocity in ambient (turbulent) conditions. In combined sewers, the marked increase of effective shear velocity associated with rain runoff events is understood to lift the coarse settleable material which ordinarily remains in a concentrated NBS flow zone, into the upper part of the flow.

Neural networks for solid transport modelling in sewer systems during storm events

Models for solid transport in sewers during storm events are increasingly used by engineers and operators to improve their systems and the quality of receiving waters. However, a major difficulty that prevents more general use of these models is their calibration, which requires field data, accurate information about catchments and sewers, and a specific methodology. Therefore, research has been carried out to assess the ability of connectionist models to reproduce and replace usual models for use by an operator. Such models require fewer data, are self-calibrated, and very easy to use. The first stage presented in this paper consists in a comparison between neural networks and the HYPOCRAS model, using simulations of real pollutographs for single storm events. Two specific recurrent neural networks based on the HYPOCRAS model and a general-purpose recurrent multilayer network are used to simulate hydrographs and pollutographs of TSS. The learning algorithm and the performance criterion used for optimization of these networks are described in detail. Experimental results with simulated and real data are then presented.

Near bed solids transport in sewers

This paper describes the results of three sewer sediment studies, carried out in Dundee, financed by the Engineering and Physical Sciences Research Council (EPSRC) and the Water Research centre (WRc). The work was carried out by the University of Abertay Dundee (Wastewater Technology Centre) as part of a collaborative research project undertaken with the University of Newcastle and the University of Sheffield. In Dundee, through collaboration with the sewerage system operator (Tayside Regional Council Water Services Department), three field sites have been established in interceptor and trunk sewer sites, since 1992, to monitor, as closely as possible, sediment and other pollutant erosion, their transport and the effects of first flushes. The physical and biochemical nature of the material being transported near the bed of real sewers has been measured. The importance of this mode of transport, in terms of mass transported and pollutant potential, is demonstrated based on data collected from the Dundee system sites. Comparisons are made between measured transport rates at the bed, at sites with and without deposited beds, with results obtained by applying empirical relationships developed to predict near bed transport in laboratory studies. A modified relationship is proposed which best fits the Dundee system data.

Neural networks for solid transport modelling in sewer systems during storm events

Models for solid transport in sewers during storm events are increasingly used by engineers and operators to improve their systems and the quality of receiving waters. However, a major difficulty that prevents more general use of these models is their calibration, which requires field data, accurate information about catchments and sewers, and a specific methodology. Therefore, research has been carried out to assess the ability of connectionist models to reproduce and replace usual models for use by an operator. Such models require fewer data, are self-calibrated, and very easy to use. The first stage presented in this paper consists in a comparison between neural networks and the HYPOCRAS model, using simulations of real pollutographs for single storm events. Two specific recurrent neural networks based on the HYPOCRAS model and a general-purpose recu

Near bed solids transport in sewers

This paper describes the results of three sewer sediment studies, carried Out in Dundee, financed by the Engineering and Physical Sciences Research Council (EPSRC) and the Water Research centre (WRc). The work was carried out by the University of Abertay Dundee (Wastewater Technology Centre) as part of a collaborative research project undertaken with the University of Newcastle and the University of Sheffield.In Dundee, through collaboration with the sewerage system operator (Tayside Regional Council Water Services Department), three field sites have been established in interceptor and trunk sewer sites, since 1992, to monitor, as closely as possible, sediment and other pollutant erosion, their transport and the effects of first flushes.The physical and biochemical nature of the material being transported near the bed of real sewers has been measured. The importance of this mode of transport, in terms of mass transported and pollutant potential, is demonstrated based on data collected from the Dundee system sites. Comparisons are made between measured transport rates at the bed, at sites with and without deposited beds, with results obtained by applying empirical relationships developed to predict near bed transport in laboratory studies. A modified relationship is proposed which best fits the Dundee system data.

Stormnet: a connectionist model for dynamic management of wastewater treatment plants during storm events

Models for solid transport in sewers during storm events are increasingly used. An important application of these models is the management of treatment plants during storm events so as to improve the quality of receiving waters. However, a major difficulty that prevents more general use of these tools is their calibration, which requires field data, accurate information about catchments and sewers, and a specific methodology. For that reason, a connectionist model called STORMNET has been designed to reproduce and replace usual conceptual and deterministic models. This model requires fewer data, can be automatically calibrated, and is comparatively simple. It is composed of two recurrent neural networks for the simulation of hydrographs and pollutographs of suspended solids, respectively. In this paper, we present an updated version of STORMNET designed for optimal management of wastewater treatment plants during storm events. This model has been validated using both model and real data. The results show the efficiency of STORMNET as a computational tool for simulating stormwater pollution.

Stormnet: A connectionist model for dynamic management of wastewater treatment plants during storm events

Models for solid transport in sewers during storm events are increasingly used. An important application of these models is the management of treatment plants during storm events so as to improve the quality of receiving waters. However, a major difficulty that prevents more general use of these tools is their calibration, which requires field data, accurate information about catchments and sewers, and a specific methodology. For that reason, a connectionist model called STORMNET has been designed to reproduce and replace usual conceptual and deterministic models. This model requires fewer data, can be automatically calibrated, and is comparatively simple. It is composed of two recurrent neural networks for the simulation of hydrographs and pollutographs of suspended solids, respectively. In this paper, we present an updated version of STORMNET designed for optimal management of wastewater treatment plants during storm events. This model has been validated using both model and real data. The results show the efficiency of STORMNET as a computational tool for simulating stormwater pollution.