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Markos Papageorgiou - One of the best experts on this subject based on the ideXlab platform.

  • linear quadratic regulators applied to Sewer Network flow control
    European Control Conference, 2003
    Co-Authors: Magdalene Marinaki, Markos Papageorgiou
    Abstract:

    The problem considered addresses the optimal wastewater distribution to several retention reservoirs in an urban Sewer Network during rainfall in the aim of protecting the quality of receiving waters via minimization of overflows. To this end, a linear multivariable feedback regulator is developed using the linear-quadratic design procedure. Inflow predictions are accommodated via suitable feedforward terms in the control law. A study for a real large-scale combined Sewer Network using this method is presented on the basis of a realistic simulation model. Results demonstrate the efficiency of the developed methodology.

  • ECC - Linear-quadratic regulators applied to Sewer Network flow control
    2003 European Control Conference (ECC), 2003
    Co-Authors: Magdalene Marinaki, Markos Papageorgiou
    Abstract:

    The problem considered addresses the optimal wastewater distribution to several retention reservoirs in an urban Sewer Network during rainfall in the aim of protecting the quality of receiving waters via minimization of overflows. To this end, a linear multivariable feedback regulator is developed using the linear-quadratic design procedure. Inflow predictions are accommodated via suitable feedforward terms in the control law. A study for a real large-scale combined Sewer Network using this method is presented on the basis of a realistic simulation model. Results demonstrate the efficiency of the developed methodology.

  • Multivariable Regulator Approach to Sewer Network Flow Control
    Journal of Environmental Engineering, 1999
    Co-Authors: Magdalene Marinaki, Markos Papageorgiou, Albert Messmer
    Abstract:

    The problem of optimal water distribution to a range of retention reservoirs in an urban Sewer Network during rainfall events is considered in this paper. The goal of the control actions is the minimization of overflows and eventually the reduction of their polluting impact on receiving waters. A multilayer control structure consisting of an adaptation, an optimization, and a direct control layer, is proposed for the solution of this complex control problem. Several approaches have been proposed with regard to the optimization layer. This paper proposes a linear multivariable feedback regulator that is developed via a systematic design procedure, including a simplified model, a quadratic minimization criterion, and subsequent application of the linear-quadratic optimization method. Inflow predictions are accommodated through feedforward terms in the control law. The control design guidelines facilitate a quick and efficient regulator design for a broad class of Sewer Network control problems. Simulation t...

  • Nonlinear optimal flow control for Sewer Networks
    Proceedings of the 1998 American Control Conference. ACC (IEEE Cat. No.98CH36207), 1998
    Co-Authors: Magdalene Marinaki, Markos Papageorgiou
    Abstract:

    The problem of optimal water distribution to several retention reservoirs in an urban Sewer Network during rainfall is considered. The goal of the control actions is the minimization of overflows and eventually the reduction of their polluting impact on receiving waters. To this end, a nonlinear optimal control approach is used and the numerical solution of the control problem is effectuated by use of a feasible direction algorithm. A detailed study of the central control problem for a particular large Sewer Network using this method is presented. Results demonstrate the efficiency and the realtime feasibility of the developed methodology.

  • multireservoir Sewer Network control via multivariable feedback
    Journal of Water Resources Planning and Management, 1992
    Co-Authors: Albert Messmer, Markos Papageorgiou
    Abstract:

    This paper considers the problem of optimal water distribution to several retention reservoirs in an urban Sewer Network during rainfall. The goal of the control actions is the minimization of overflows and eventually the reduction of their polluting impact on receiving waters. Decomposition of the overall control task into a local‐flow control layer and a global coordinating control layer is assumed. For the global control task, a linear multivariable feedback regulator is developed via a systematic design procedure including a simplified model approach, a quadratic minimization criterion and subsequent application of the linear quadratic optimization method. The proposed control design guidelines facilitate quick and efficient regulator design for a broad class of Sewer‐Network control problems. A simulation study was performed for a particular Network by use of an accurate hydrodynamic simulation model. Simulation results indicate significant overflow reductions achieved by the application of the multi...

Hongxiang Chai - One of the best experts on this subject based on the ideXlab platform.

  • A Novel SWMM Based Algorithm Application to Storm Sewer Network Design
    Water, 2017
    Co-Authors: Shao Zhiyu, Xiaoyuan Zhang, Li Shuang, Deng Shihu, Hongxiang Chai
    Abstract:

    An automated algorithm based on the dynamic hydrological and hydraulic simulation modules in Storm Water Management Model (SWMM) was developed to aid the design of storm Sewer Networks, provided that a layout is given. Numerical performance of the proposed algorithm was compared with the existing design methods with two application cases. The automated computation process of the Sewer Network design was divided into two stages and solved iteratively, determining pipe diameter and pipe slope, respectively. In the first stage, starting with a set of initial values including pipe diameter, pipe cover depth, and ground elevation at manholes, the iteration was carried out from the downstream to the upstream while the pipe slopes of the Network were assumed to be fixed and the diameter of each pipe segment was calculated. In the second stage, pipe diameters calculated from the first stage were fixed and the pipe slopes were calculated successively from the downstream pipe segment to the upstream pipe segment. Every time the diameter or slope of a pipe segment was adjusted, the pipe flow rate, velocity, and flow depth were obtained by running SWMM hydrological and hydraulic simulation modules. The iteration terminated once the combination scheme of pipe diameters and slopes met the design ordinance which requires the pipe flows full under gravity in a design return period. A real urban Sewer system in a hilly city and a benchmark Sewer Network from the literature were tested to validate the proposed automated algorithm, and good performance was shown. The automated design results explicitly show that the proposed storm Sewer design approach leads to a quality solution with reduced computational effort.

T. Bersinger - One of the best experts on this subject based on the ideXlab platform.

  • online monitoring and conditional regression tree test useful tools for a better understanding of combined Sewer Network behavior
    Science of The Total Environment, 2018
    Co-Authors: T. Bersinger, Gilles Bareille, Thierry Pigot, Noëlle Bru, Le I Hecho
    Abstract:

    A good knowledge of the dynamic of pollutant concentration and flux in a combined Sewer Network is necessary when considering solutions to limit the pollutants discharged by combined Sewer overflow (CSO) into receiving water during wet weather. Identification of the parameters that influence pollutant concentration and flux is important. Nevertheless, few studies have obtained satisfactory results for the identification of these parameters using statistical tools. Thus, this work uses a large database of rain events (116 over one year) obtained via continuous measurement of rainfall, discharge flow and chemical oxygen demand (COD) estimated using online turbidity for the identification of these parameters. We carried out a statistical study of the parameters influencing the maximum COD concentration, the discharge flow and the discharge COD flux. In this study a new test was used that has never been used in this field: the conditional regression tree test. We have demonstrated that the antecedent dry weather period, the rain event average intensity and the flow before the event are the three main factors influencing the maximum COD concentration during a rainfall event. Regarding the discharge flow, it is mainly influenced by the overall rainfall height but not by the maximum rainfall intensity. Finally, COD discharge flux is influenced by the discharge volume and the maximum COD concentration. Regression trees seem much more appropriate than common tests like PCA and PLS for this type of study as they take into account the thresholds and cumulative effects of various parameters as a function of the target variable. These results could help to improve Sewer and CSO management in order to decrease the discharge of pollutants into receiving waters.

  • Online monitoring and conditional regression tree test: Useful tools for a better understanding of combined Sewer Network behavior.
    Science of the Total Environment, 2018
    Co-Authors: T. Bersinger, Gilles Bareille, T. Pigot, Noëlle Bru, I. Le Hécho
    Abstract:

    A good knowledge of the dynamic of pollutant concn. and flux in a combined Sewer Network is necessary when considering solns. to limit the pollutants discharged by combined Sewer overflow (CSO) into receiving water during wet weather. Identification of the parameters that influence pollutant concn. and flux is important. Nevertheless, few studies have obtained satisfactory results for the identification of these parameters using statistical tools. Thus, this work uses a large database of rain events (116 over one year) obtained via continuous measurement of rainfall, discharge flow and COD (COD) estd. using online turbidity for the identification of these parameters. We carried out a statistical study of the parameters influencing the max. COD concn., the discharge flow and the discharge COD flux. In this study a new test was used that has never been used in this field: the conditional regression tree test. We have demonstrated that the antecedent dry weather period, the rain event av. intensity and the flow before the event are the three main factors influencing the max. COD concn. during a rainfall event. Regarding the discharge flow, it is mainly influenced by the overall rainfall height but not by the max. rainfall intensity. Finally, COD discharge flux is influenced by the discharge vol. and the max. COD concn. Regression trees seem much more appropriate than common tests like PCA and PLS for this type of study as they take into account the thresholds and cumulative effects of various parameters as a function of the target variable. These results could help to improve Sewer and CSO management in order to decrease the discharge of pollutants into receiving waters.

Shuliang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Impact of the Storm Sewer Network Complexity on Flood Simulations According to the Stroke Scaling Method
    Water, 2018
    Co-Authors: Qiqi Yang, Qiang Dai, Dawei Han, Xuehong Zhu, Shuliang Zhang
    Abstract:

    For urban watersheds, the storm Sewer Network provides indispensable data for flood modeling but often needs to be simplified to balance the conflict between the large amount of data and current computing power. The sensitivity of a flood simulation to the data precision of a storm Sewer Network needs to be explored to develop reasonable generalization strategies. In this study, the impact of using the stroke scaling method to generalize a storm Sewer Network on a flood simulation was analyzed in terms of the total inflow of the outfalls and flood results. The results of the three study basins showed that different complexities of a Sewer Network did not have a significant effect on the outfall’s total inflow for an area with a single drainage system but did for an area with multiple drainage systems. In addition, serious flooding was mainly distributed at the backbone pipes, which can be identified with the simplified Sewer Network. Several effective generalization strategies were developed for Sewer Networks that consider the distribution characteristics of the drainage system and application requirements. This study is theoretically important for better understanding the data sensitivity of flood modeling and simulation and practically important for improving the modeling efficiency and the accuracy of urban flood simulation.

Shao Zhiyu - One of the best experts on this subject based on the ideXlab platform.

  • A Novel SWMM Based Algorithm Application to Storm Sewer Network Design
    Water, 2017
    Co-Authors: Shao Zhiyu, Xiaoyuan Zhang, Li Shuang, Deng Shihu, Hongxiang Chai
    Abstract:

    An automated algorithm based on the dynamic hydrological and hydraulic simulation modules in Storm Water Management Model (SWMM) was developed to aid the design of storm Sewer Networks, provided that a layout is given. Numerical performance of the proposed algorithm was compared with the existing design methods with two application cases. The automated computation process of the Sewer Network design was divided into two stages and solved iteratively, determining pipe diameter and pipe slope, respectively. In the first stage, starting with a set of initial values including pipe diameter, pipe cover depth, and ground elevation at manholes, the iteration was carried out from the downstream to the upstream while the pipe slopes of the Network were assumed to be fixed and the diameter of each pipe segment was calculated. In the second stage, pipe diameters calculated from the first stage were fixed and the pipe slopes were calculated successively from the downstream pipe segment to the upstream pipe segment. Every time the diameter or slope of a pipe segment was adjusted, the pipe flow rate, velocity, and flow depth were obtained by running SWMM hydrological and hydraulic simulation modules. The iteration terminated once the combination scheme of pipe diameters and slopes met the design ordinance which requires the pipe flows full under gravity in a design return period. A real urban Sewer system in a hilly city and a benchmark Sewer Network from the literature were tested to validate the proposed automated algorithm, and good performance was shown. The automated design results explicitly show that the proposed storm Sewer design approach leads to a quality solution with reduced computational effort.