scholarly journals No-regret selection of effective control handles for integrated urban wastewater systems management under parameter and input uncertainty

2020 ◽  
Vol 81 (8) ◽  
pp. 1749-1756 ◽  
Author(s):  
J. M. Ledergerber ◽  
T. Maruéjouls ◽  
P. A. Vanrolleghem
Keyword(s):  
Global Sensitivity Analysis ◽  
Screening Method ◽  
Real Life ◽  
Effective Control ◽  
Urban Wastewater ◽  
Sewer System ◽  
Input Uncertainty ◽  
Wastewater Systems ◽  
Selection Of

Abstract Regulatory water quality limits are extended from the wastewater resource recovery facility (WRRF) to the sewer system. It is thus necessary to properly integrate those systems for the evaluation of the overall emissions to the receiving water. The integration of the sewer system and the WRRF, however, leaves us with multiple potential options to reduce these emissions. The proposed approach builds on previous research using global sensitivity analysis (GSA) as a screening method for available control handles. It considers parameter and input uncertainty to select control handles that generate large benefits even if the model differs from reality. Results from a real-life case study indicate that the three top-rated handles are comparably effective for all considered uncertainty and variability scenarios. But the results also showed that this does not apply to lower-rated handles.

scholarly journals Energy Balance in Wastewater Systems with Energy Recovery: A Portuguese Case Study

2021 ◽  
Vol 6 (10) ◽  
pp. 141
Author(s):  
Catarina Jorge ◽  
Maria do Céu Almeida ◽  
Dídia Covas
Keyword(s):  
Energy Efficiency ◽  
Energy Balance ◽  
Energy Recovery ◽  
Real Life ◽  
Wet Season ◽  
Current Case ◽  
Total Input ◽  
Wastewater Systems ◽  
Regional Reference

This paper presents and discusses the application of a novel energy balance scheme for assessing energy efficiency in wastewater systems. The energy balance is demonstrated with a Portuguese real-life case study, using mathematical modelling to estimate the different energy components and to compute two energy efficiency indices. The total inflow intrinsic energy can represent a significant amount (>95%) of the total energy used in systems mainly composed of gravity sewers. The total input energy is significantly (four-times) higher in the wet season than in the dry season, mostly due to undue inflows (e.g., direct rainfall and infiltration). The potential for energy recovery strongly depends on the available head and flow rate at the delivery point, being 0.01 kWh/m3 in the current case, with a project payback period of 4 years. The energy balance components and the respective energy efficiency indices strongly depend on the considered reference elevation. Thus, a unique regional reference elevation is recommended in the calculations.

Optimisation of control strategies for the urban wastewater system - an integrated approach

1999 ◽  
Vol 39 (9) ◽  
pp. 209-216 ◽  
Author(s):  
Manfred Schütze ◽  
David Butler ◽  
M. Bruce Beck
Keyword(s):  
Control Strategies ◽  
Integrated Control ◽  
Water Quality Management ◽  
Treatment Plant ◽  
Integrated Approach ◽  
Urban Wastewater ◽  
Sewer System ◽  
Integrated Simulation ◽  
Case Study Site

Currently, the sewer system, treatment plant and receiving water body are normally considered as separate units in water quality management. The study reported in this paper analyses the potential of integrated control of the urban wastewater system in its entirety. Assembly and implementation of an integrated simulation and optimisation tool, named SYNOPSIS, are presented. This software package allows water quantity and quality processes in the urban wastewater system to be simulated. Furthermore, optimisation modules included in this tool can be applied for off-line optimisation of control strategies. This procedure is exemplified for a semi-hypothetical case study site. Results obtained for this case study suggest that integrated control of the urban wastewater system can indeed lead to some improvement of its performance. This study demonstrates that a tool is now available for assessment of the potential of integrated control.

scholarly journals SCALE IN REGIONAL ENVIRONMENTAL PLANNING: THE RECONSTRUCTION OF NORTH-BRABANT, THE NETHERLANDS

2012 ◽  
Vol 14 (01) ◽  
pp. 1250004 ◽  
Author(s):  
ANDRE KOOIMAN ◽  
SUKHAD SUBODH KESHKAMAT
Keyword(s):  
The Netherlands ◽  
Environmental Planning ◽  
Information Science ◽  
Academic Research ◽  
Real Life ◽  
Geographic Information ◽  
Boundary Object ◽  
Theoretical Concepts ◽  
Selection Of

Selection of scale in science and planning is often guided by ad-hoc decisions and arguments of accuracy and availability of existing data and resources. A more analytical approach to selection of scale and a bridge between theoretical insight and practical application is required. This paper reviews recent developments in thinking on theoretical concepts on scale from the perspective of geo-information science and compares these with a real life case. The concept of scale is framed as a three dimensional boundary object that explains scale choice as resultant of rationalities in reality-, model- and data scales. It is applied to a case-study of how issues of scale were handled in the Reconstruction program of the Province of North Brabant in The Netherlands. The Reconstruction is an ongoing regional spatial planning exercise that started in the year 2000 in response to major veterinary, environmental, social and economic problems in areas with concentrations of intensive livestock keeping. It combines legislation and policies at international, national, regional and municipal levels. Geographic information was produced to support and present the results of the plan process and related SEA. Scale of various intermediate and final geo-information products varied from 1:5000–1:400,000 and was dependent on the plan stage, plan status and target audience, plan instrument, level of participation, data characteristics, costs and technology. By comparing theory with the case study we bring out the criteria and conditions of selection of appropriate scale whereby the usefulness of academic research in geographic information science for planning and decision making could be improved.

scholarly journals A BAYESIAN APPROACH BASED ON ACQUISITION FUNCTION FOR OPTIMAL SELECTION OF DEEP LEARNING HYPERPARAMETERS: A CASE STUDY WITH ENERGY MANAGEMENT DATA

2020 ◽  
Vol 2 (1) ◽  
pp. 22-27
Author(s):  
MUHAMMAD ALI ◽  
Krishneel Prakash ◽  
Hemanshu Pota
Keyword(s):  
Deep Learning ◽  
Energy Management ◽  
Bayesian Approach ◽  
Learning Algorithm ◽  
Real Life ◽  
Model Parameters ◽  
Optimal Parameters ◽  
Comparison Results ◽  
Selection Of

With the recent rollout of smart meters, huge amount of data can be generated on hourly and daily basis. Researchers and industry persons can leverage from this big data to make intelligent decisions via deep learning (DL) algorithms. However, the performance of DL algorithms are heavily dependent on the proper selection of parameters. If the hyperparameters are poorly selected, they usually lead to suboptimal results. Traditional approaches include a manual setting of parameters by trial and error methods which is time consuming and difficult process.  In this paper, a Bayesian approach based on acquisition is presented to automatic selection of optimal parameters based on provided data. The acquisition function was established to search for the best parameter from the input space and evaluate the next points based on past observations. The tuning process identifies the best model parameters by iterating the objective function and minimizing the loss for optimizable variables such as learning rate and Hidden layersize. To validate the presented approach, we conducted a case study on real-life energy management datasets while constructing a deep learning model on MATLAB platform. A performance comparison was drawn with random parameters and optimal parameters selected by presented approach. The comparison results illustrate that the presented approach is effective as it brings a notable improvement in the performance of learning algorithm.

The HSG procedure for modelling integrated urban wastewater systems

2009 ◽  
Vol 60 (8) ◽  
pp. 2065-2075 ◽  
Author(s):  
D. Muschalla ◽  
M. Schütze ◽  
K. Schroeder ◽  
M. Bach ◽  
F. Blumensaat ◽  
...  
Keyword(s):  
Data Availability ◽  
Integrated Modelling ◽  
Urban Wastewater ◽  
Simulation Research ◽  
Central European ◽  
Modelling Studies ◽  
Research Findings ◽  
Wastewater Systems ◽  
Definition Of ◽  
Selection Of

Whilst the importance of integrated modelling of urban wastewater systems is ever increasing, there is still no concise procedure regarding how to carry out such modelling studies. After briefly discussing some earlier approaches, the guideline for integrated modelling developed by the Central European Simulation Research Group (HSG - Hochschulgruppe) is presented. This contribution suggests a six-step standardised procedure to integrated modelling. This commences with an analysis of the system and definition of objectives and criteria, covers selection of modelling approaches, analysis of data availability, calibration and validation and also includes the steps of scenario analysis and reporting. Recent research findings as well as experience gained from several application projects from Central Europe have been integrated in this guideline.

scholarly journals Process-based selection of copula types for flood peak-volume relationships in Northwest Austria: a case study

2016 ◽  
Vol 46 (4) ◽  
pp. 245-268 ◽  
Author(s):  
Silvia Kohnová ◽  
Ladislav Gaál ◽  
Tomáš Bacigál ◽  
Ján Szolgay ◽  
Kamila Hlavčová ◽  
...  
Keyword(s):  
Sample Size ◽  
Goodness Of Fit ◽  
Real Life ◽  
Flash Floods ◽  
Flood Events ◽  
Copula Models ◽  
Flood Peak ◽  
Flood Peaks ◽  
Selection Of

Abstract The case study aims at selecting optimal bivariate copula models of the relationships between flood peaks and flood volumes from a regional perspective with a particular focus on flood generation processes. Besides the traditional approach that deals with the annual maxima of flood events, the current analysis also includes all independent flood events. The target region is located in the northwest of Austria; it consists of 69 small and mid-sized catchments. On the basis of the hourly runoff data from the period 1976- 2007, independent flood events were identified and assigned to one of the following three types of flood categories: synoptic floods, flash floods and snowmelt floods. Flood events in the given catchment are considered independent when they originate from different synoptic situations. Nine commonly-used copula types were fitted to the flood peak - flood volume pairs at each site. In this step, two databases were used: i) a process-based selection of all the independent flood events (three data samples at each catchment) and ii) the annual maxima of the flood peaks and the respective flood volumes regardless of the flood processes (one data sample per catchment). The goodness-of-fit of the nine copula types was examined on a regional basis throughout all the catchments. It was concluded that (1) the copula models for the flood processes are discernible locally; (2) the Clayton copula provides an unacceptable performance for all three processes as well as in the case of the annual maxima; (3) the rejection of the other copula types depends on the flood type and the sample size; (4) there are differences in the copulas with the best fits: for synoptic and flash floods, the best performance is associated with the extreme value copulas; for snowmelt floods, the Frank copula fits the best; while in the case of the annual maxima, no firm conclusion could be made due to the number of copulas with similarly acceptable overall performances. The general conclusion from this case study is that treating flood processes separately is beneficial; however, the usually available sample size in such real life studies is not sufficient to give generally valid recommendations for engineering design tasks.

Methodology for Locking Feature Selection in Integral Snap-Fit Assembly

1997 ◽  
Author(s):  
Suat Genc ◽  
Robert W. Messler ◽  
Gary A. Gabriele
Keyword(s):  
Feature Selection ◽  
Systematic Approach ◽  
Real Life ◽  
Integral Attachment ◽  
Selection Of

Abstract While every step in a systematic approach to the design of an assembly for integral attachment using snap-fit features is important, none is more important than the selection of locking features. After all, it is these features that hold the assembly together. Comprised of a latch and catch component, locking pairs must themselves be selected using a systematic approach. This paper presents that approach as a six-step methodology, after defining and describing latch and catch components. It then demonstrates the methodology using a case study taken from real life.

Impacto de afluências indevidas no consumo energético em instalações elevatórias em sistemas de drenagem urbana

2020 ◽  
pp. 29-40
Author(s):  
Catarina Jorge ◽  
◽  
Maria do Céu Almeida ◽  
Dídia Covas
Keyword(s):  
Sensitivity Analysis ◽  
Energy Management ◽  
Energy Use ◽  
Real Life ◽  
Pumping Stations ◽  
Relevant Variables ◽  
Wastewater Systems ◽  
Separate System ◽  
The Impact

As afluências indevidas são identificadas como um dos principais problemas dos sistemas de águas residuais e pluviais, levando a diversos problemas de desempenho dos mesmos, como sejam a ocorrência de inundações, a diminuição da eficiência hidráulica e energética, entre outros. A atuação no controlo de afluências indevidas perspetiva oportunidades de melhoria do desempenho em várias dimensões incluindo a componente de eficiência energética. Neste artigo desenvolve-se esta temática numa perspetiva de avaliação do desempenho de instalações elevatórias (IE) embora considerando o sistema como um todo. A metodologia adotada consiste em efetuar a análise de sensibilidade de um sistema separativo de águas residuais para cenários de ocorrência de afluências indevidas à rede, de modo a avaliar o impacto no consumo de energia e noutras variáveis relevantes do sistema. O caso de estudo utilizado consiste numa adaptação do caso de estudo real correspondente ao sistema de drenagem de águas residuais da Bacia da Venteira, Amadora. A finalidade é aferir uma abordagem para tratar esta temática de modo mais geral com base no caso de estudo referido, de forma a contribuir para a sensibilização para a adoção de metodologias operacionais e de monitorização que permitam ter dados para fazer uma gestão mais racional da energia nestes sistemas. As conclusões são genericamente aplicáveis a qualquer sistema separativo de águas residuais. Undue inflows are identified as one of the main problems in wastewater and stormwater systems, leading to several performance issues, such as flooding, decreased efficiency in water and energy use, among others. Acting in the control of undue inflows leads to performance enhancements in several dimensions including the energy efficiency component. This paper presents developments regarding performance evaluation of pumping stations, although considering the system as a whole. The proposed methodology consists of adopting a sensitivity analysis for a separate wastewater system, considering scenarios of undue inflows occurrences in the network, in order to evaluate the impact on energy consumption and other relevant variables of the system. The case study presented herein is adapted from a real life case study corresponding to the Venteira's domestic separate system (located at Amadora, Portugal). The main purpose is to assess an approach to address this issue, in order to contribute to increase awareness for the adoption of operational and monitoring methodologies to contribute for a more rational energy management in these systems. The conclusions are generally applicable to separate wastewater systems.

Release of hydrogen sulfide in a sewer system under intermittent flow conditions: the Ericeira case study, in Portugal

2017 ◽  
Vol 75 (7) ◽  
pp. 1702-1711 ◽  
Author(s):  
Natércia Matias ◽  
Rita Ventura Matos ◽  
Filipa Ferreira ◽  
Jes Vollertsen ◽  
José Saldanha Matos
Keyword(s):  
Hydrogen Sulfide ◽  
Corrosion Damage ◽  
Intermittent Flow ◽  
Rapid Decline ◽  
Sewer System ◽  
Phase Measurements ◽  
Wastewater Systems ◽  
Dissolved Sulfide ◽  
Intensive Sampling

The presence and fate of hydrogen sulfide in wastewater systems were studied in two stretches of an intercepting sewer system located in a coastal village, in Portugal. A range of hydraulic parameters were obtained and liquid and gas phase measurements were carried out, both continuously and through intensive sampling campaigns. Upstream, where flow rates were relatively low, dissolved sulfide concentrations around 12 mg S L−1 and hydrogen sulfide gas concentrations above 250 ppm were observed, along with limited corrosion damage. It is believed this is due to the low relative humidity detected along the atmosphere of the studied sewer system. Downstream, gas concentrations were always below 40 ppm. Despite that, high signs of corrosion were detected, particularly in manholes with drop structures. It is thought that condensation of spray produced by the fall is the main cause of the phenomenon. Another relevant observation was the rapid decline in dissolved sulfide contents along gravity trunk sewers following the discharge of rising mains, with loss rates as high as 40 mg S L−1 h−1. Air-flow velocities corresponded to 15–50% of wastewater flows, an observation which agrees with other authors' publications addressing relatively small pipes and moderate water flows.

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