36 results
Search Results
2. Trialling urine diversion in Australia: technical and social learnings.
- Author
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Abeysuriya, Kumi, Fam, Dena, and Mitchell, Cynthia
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URINE , *TOILETS , *COMMERCIAL buildings , *PERFORMANCE evaluation - Abstract
This paper discusses a urine diversion (UD) trial implemented within the institutional setting of the University of Technology Sydney that sought to identify key issues for public UD and reuse systems at scale in the Australian urban context. The trial was novel in its transdisciplinary action research approach, that included consideration of urine diverting toilets (UDTs) as socio-technical systems where interactions between users' practices and perceptions and the performance of the technology were explored. While the study explored a broad range of issues that included urine transport, reuse, and regulations, amongst others, the boundary of the work presented in this paper is the practicalities of UD practice within public urban buildings. Urine volume per urinal use, an important metric for sizing tanks for collecting urine from waterless urinal systems in commercial buildings, was also estimated. The project concluded that current UDTs are unsuitable to public/commercial spaces, but waterless urinals have a key role. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
3. Elements for setting up discharge standards in developing countries based on actual wastewater treatment plant performance.
- Author
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Oliveira, Sílvia C. and von Sperling, Marcos
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INDUSTRIAL wastes , *WASTEWATER treatment , *WATER quality management , *TECHNOLOGICAL innovations , *SEWAGE purification , *UPFLOW anaerobic sludge blanket (UASB) reactor , *SEWAGE disposal plants , *FACTORIES & the environment , *PLANT performance , *FACTORY sanitation - Abstract
The paper analyses the capability of 166 full-scale wastewater treatment plants operating in Brazil, in order to achieve different quality targets for wastewater discharge. These targets cover a wide range of possible situations, reflecting usual practices adopted worldwide. Six different treatment processes have been investigated: septic tank + anaerobic filter, facultative pond, anaerobic pond + facultative pond, activated sludge, UASB reactors alone, UASB reactors followed by post-treatment. The parameters investigated were: BOD, COD, suspended solids, total nitrogen, total phosphorus and thermotolerant coliforms. Most technologies showed a poor performance, and some of them were not capable to achieve even relaxed standards. The paper presents elements for setting up discharge standards in developing countries, based either on values that may be achieved by treatment processes commonly applied or on best available technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
4. Towards a benchmark simulation model for plant-wide control strategy performance evaluation of WWTPs.
- Author
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Jeppsson, U., Rosen, C., Alex, J., Copp, J., Gernaey, K. V., Pons, M.-N., and Vanrolleghem, P. A.
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BENCHMARKING (Management) , *SIMULATION methods & models , *SEWAGE sludge , *SCIENTIFIC community , *PERFORMANCE evaluation , *SEWAGE purification , *WASTEWATER treatment , *SEWAGE disposal plants , *WATER purification - Abstract
The COST/IWA benchmark simulation model has been available for seven years. Its primary purpose has been to create a platform for control strategy benchmarking of activated sludge processes. The fact that the benchmark has resulted in more than 100 publications, not only in Europe but also worldwide, demonstrates the interest in such a tool within the research community In this paper, an extension of the benchmark simulation model no 1 (BSM1) is proposed. This extension aims at facilitating control strategy development and performance evaluation at a plant-wide level and, consequently, includes both pre- treatment of wastewater as well as the processes describing sludge treatment. The motivation for the extension is the increasing interest and need to operate and control wastewater treatment systems not only at an individual process level but also on a plant-wide basis. To facilitate the changes, the evaluation period has been extended to one year. A prolonged evaluation period allows for long-term control strategies to be assessed and enables the use of control handles that cannot be evaluated in a realistic fashion in the one- week BSM1 evaluation period. In the paper, the extended plant layout is proposed and the new suggested process models are described briefly. Models for influent file design, the benchmarking procedure and the evaluation criteria are also discussed. And finally, some important remaining topics, for which consensus is required, are identified. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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5. Ottoman period water structures and water-related architecture: examples in Safranbolu, Turkey.
- Author
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Ertürk, A. Esra Bölükbaşı, Şeker, Dursun Zafer, and Öztürk, İzzet
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WATER supply ,INTERNATIONAL tourism ,DRINKING water ,AQUEDUCTS ,PERFORMANCE evaluation - Abstract
Safranbolu is known for the abundance of its water resources. The city is a unique and historic settlement that hosts very beautiful examples of traditional Turkish architecture. The city attracts both national and international tourists. In this paper, firstly the Ottoman period water supply structures of Safranbolu are described. Incekaya Aqueduct and water transmission system, also known as the Pasha Water Supply System or Spring System are discussed. The Incekaya Aqueduct delivers drinking water from the spring at Danaköy Village to Safranbolu enabling the transfer over the Tokatlı Canyon via gravity. This aqueduct, a very historic and aesthetically pleasing water structure, was commissioned as a city asset by Ottoman Grand Vizier Izzet Mehmet Pasha in the period of 1794-98. The paper secondly discusses the pool rooms that serve as an example of the spatial usage of water features in traditional residential architecture of the Ottoman period in Safranbolu. The pool rooms were constructed either within or separate from the traditional Safranbolu mansions. Asmazlar Mansion in Safranbolu and Deligözler House in the Bağlar District have been evaluated as examples of pool rooms within the house, and two garden pools in the Bağlar and central districts are assessed as examples of outside pools, known as pavilion mansions with a garden pool. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
6. Flooding management using hybrid model predictive control: application to the Spanish Ebro River.
- Author
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Romera, J., Ocampo-Martinez, C., Puig, V., and Quevedo, J.
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FLOOD control , *HYBRID systems , *PREDICTIVE control systems , *PERFORMANCE evaluation , *PREDICTION models , *PROBLEM solving - Abstract
In this paper, the problem of flooding management using hybrid model predictive control is presented and applied to the Ebro River in Spain. The Ebro River presents flooding episodes in the city of Zaragoza during spring when snow melts in the Pyrenees. To avoid flooding in populated areas, some land outside the city is prepared for flooding. This paper presents a control approach to determine and fix the level of flooding in pre-established zones by controlling side gates that determine the water input to the land to be flooded. Finally, several scenarios are used to validate the performance of the proposed approach. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
7. A novel hybrid mechanistic-data-driven model identification framework using NSGA-II.
- Author
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Shari, Soroosh and Massoudieh, Arash
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GENETIC algorithms , *EVOLUTIONARY computation , *SUSPENDED solids , *RUNOFF , *MATHEMATICAL models , *REGRESSION analysis , *PERFORMANCE evaluation - Abstract
This paper describes a novel evolutionary data-driven model (DDM) identification framework using the NSGA-II multi-objective genetic algorithm. The central concept of this paper is the employment of evolutionary computation to search for model structures among a catalog of models, while honoring the physical principles and the constitutive theories commonly used to represent the system/processes being modeled. The presented framework provides high computational efficiency through connecting a series of NSGA-II runs which share results. Furthermore, the employment of a multi- objective optimization algorithm enables a unique way of incorporating different aspects of model goodness in the model selection process, and also, at the end of the search procedure, provides a number of potential optimal model structures, making it possible for the modeler to make a choice based on the goal of the modeling. As an illustration, the framework is used for modeling wash-off and build-up of suspended solids (TSS) in highway runoff. The performance of the discovered model confirms the potential of the proposed evolutionary DDM framework for modeling environmental processes. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
8. Pipe burst diagnostics using evidence theory.
- Author
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Bicik, Josef, Kapelan, Zoran, Makropoulos, Christos, and Savić, Dragan A.
- Subjects
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PIPE bursting (Underground construction) , *DECISION support systems , *WATER distribution , *MATHEMATICAL models , *HYDRAULIC models , *DEMPSTER-Shafer theory , *PERFORMANCE evaluation - Abstract
This paper presents a decision support methodology aimed at assisting Water Distribution System (WDS) operators in the timely location of pipe bursts. This will enable them to react more systematically and promptly. The information gathered from various data sources to help locate where a pipe burst might have occurred is frequently conflicting and imperfect. The methodology developed in this paper deals effectively with such information sources. The raw data collected in the field is first processed by means of several models, namely the pipe burst prediction model, the hydraulic model and the customer contacts model. The Dempster-Shafer Theory of Evidence is then used to combine the outputs of these models with the aim of increasing the certainty of determining the location of a pipe burst within a WDS. This new methodology has been applied to several semi-real case studies. The results obtained demonstrate that the method shows potential for locating the area of a pipe burst by capturing the varying credibility of the individual models based on their historical performance. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
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9. Quantitative studies of water and sanitation utilities: a benchmarking literature survey.
- Author
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Berg, S. and Marques, R.
- Subjects
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SANITATION , *QUANTITATIVE research , *BENCHMARKING (Management) , *PERFORMANCE evaluation , *ECONOMIC trends - Abstract
This paper performs a literature update of quantitative studies of water and sanitation services (WSS), with an emphasis on tracking the benchmarking literature. There are 190 studies which use cost or production functions to evaluate the performance of WSS utilities. The studies examine: (1) the scale, scope or density economies of utilities in a particular country or region; (2) the influence of ownership on efficiency; (3) the existence and power of incentives associated with different governance systems (including external regulation); and (4) performance assessment (benchmarking). In addition, this paper presents patterns regarding quantitative methods adopted over time, as well as some major trends in results. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
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10. Augmentation of an artificial neural network and modified stochastic dynamic programing model for optimal release policy.
- Author
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Fayaed, Sabah S., El-Shafie, Ahmed, Alsulami, Humod Mosad, Jaafar, Othman, Mukhlisin, Muhammad, and El-Shafie, Amr
- Subjects
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ARTIFICIAL neural networks , *STOCHASTIC processes , *DYNAMIC programming , *STRATEGIC planning , *PERFORMANCE evaluation - Abstract
In this paper, a comprehensive modified stochastic dynamic programing with artificial neural network (MSDP-ANN) model is developed and applied to derive optimal operational strategies for a reservoir. Most water resource problems involve uncertainty. To show that the MSDP-ANN model addresses uncertainty in the input variable, the result of the MSDP-ANN model is compared with the performance of a detailed conventional stochastic dynamic programing with regression analysis (CSDP-RA) model. The computational time of the CSDP-ANN model is modified with concave objective functions by deriving a monotonic relationship between the reservoir storage and optimal release decision, and an algorithm is proposed to improve the computational efficiency of reservoir operation. Various indices (i.e. reliability, vulnerability, and resiliency) were calculated to assess the model performance. After comparing the performance of the CSDP-RA model with that of the MSDPANN model, it was observed that the MSDP-ANN model produces a more reliable and resilient model and a smaller supply deficit. Thus, it can be concluded that the MSDP-ANN model performs better than the CSDP-RA model in deriving the optimal operating policy for the reservoir. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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11. Performance comparison between two equal stabilization ponds operating with and without sludge layer.
- Author
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Rodrigues, V. A. J., Possmoser-Nascimento, T. E., Dias, D. F. C., Passos, R. G., von Sperling, M., and Vasel, J. L.
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SEWAGE lagoons , *PERFORMANCE evaluation , *SEWAGE purification , *BIOCHEMICAL oxygen demand , *SUSPENDED solids , *COLIFORMS - Abstract
Stabilization ponds are a highly appropriate system for treating sewage in small to medium size communities. However, sludge accumulation at the pond bottom occurs with the passage of time, reducing the net pond volume, which, in principle, could affect its performance. The objective of this paper is to compare the behaviour of two equal ponds in parallel treating the same flow of municipal wastewater from an upflow anaerobic sludge blanket reactor in Brazil. Each pond treated a population equivalent of around 125 inhabitants. One pond had approximately 40% of its net volume occupied by sludge after 11 years of operation, while the other pond had previously undergone complete desludging. The study covers the removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), nitrogen fractions and coliforms. Owing to the presence of a sludge layer, the theoretical hydraulic retention time (HRT) was lower in the pond without sludge. For BOD, COD, SS and Escherichia coli there were no significant differences (Wilcoxon matched-pairs test) between both ponds. The pond without sludge had significantly better removal efficiencies in terms of total Kjeldahl nitrogen and ammonia-N. The sludge layer probably allowed the occurrence of removal mechanisms that compensated for the reduction caused in the HRT. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
12. Performance characterisation of a constructed Wetland.
- Author
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Mangangka, Isri R., Egodawatta, Prasanna, Parker, Nathaniel, Gardner, Ted, and Goonetilleke, Ashantha
- Subjects
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CONSTRUCTED wetlands , *PERFORMANCE evaluation , *PURIFICATION of runoff , *WATER quality , *WATER pollution , *PHOSPHORUS in water - Abstract
Performance of a constructed wetland is commonly reported as being variable due to the site specific nature of influential factors. This paper discusses the outcomes from an in-depth study which characterised the treatment performance of a wetland based on the variation in the runoff regime. The study included a comprehensive field monitoring of a well-established constructed wetland in Gold Coast, Australia. Samples collected at the inlet and outlet were tested for Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP). Pollutant concentrations in the outflow were found to be consistent irrespective of the variation in inflow water quality. The analysis revealed two different treatment characteristics for events with different rainfall depths. TSS and TN load reduction was found to be strongly influenced by the hydraulic retention time where performance was relatively superior for rainfall events below the design event. For small events, treatment performance was higher at the beginning of the event and gradually decreased during the course of the event. For large events, the treatment performance was comparatively poor at the beginning and improved during the course of the event. The analysis also confirmed the variable treatment trends for different pollutant types. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
13. Performance indices for water network partitioning and sectorization.
- Author
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Di Nardo, A., Di Natale, M., Santonastaso, G. F., Tzatchkov, V. G., and Alcocer-Yamanaka, V. H.
- Subjects
WATER management ,WATER pollution ,PERFORMANCE evaluation ,WATER supply ,COMPARATIVE studies ,REDUNDANCY in engineering - Abstract
Water network partitioning in district metering areas, or sectorization, is an important process for improving water network management. It can help water utilities to implement active leakage control, conduct pressure management, and prevent network contamination. It is generally achieved by closing some network pipes, thus reducing pipe redundancy and affecting system performance. No systematic set of performance indices has been defined to evaluate a sectorization design and thus allow for a comparison of different possible sectorizations on a formal basis. In this paper, several performance indices for water network partitioning are proposed and tested using two real water supply systems: Parete in Italy and Matamoros in Mexico. Both systems' sectorizations were previously designed by a novel effective automatic technique recently developed by the authors. For both the original and sectorized networks, the proposed performance indices considered energy dissipated in the network, network resilience, pressure variation, fire-fighting capacity, water age, and mechanical redundancy. Network resilience appears to be the most representative index for the entire network, whereas pressure variation indices are more appropriate for describing individual districts. Except for fire-fighting capacity in one network, system performance did not appear to be affected significantly after sectorization. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
14. Experimental comparison of canal models for control purposes using simulation and laboratory experiments.
- Author
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Horváth, Klaudia, Galvis, Eduard, Rodellar, José, and Valentín, Manuel Gómez
- Subjects
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WATER conservation , *CANALS , *SIMULATION methods & models , *AUTOMATIC control systems , *DATA analysis , *PERFORMANCE evaluation , *CONCEPTUAL models - Abstract
Considerable amounts of water can be saved by automating irrigation canals. The design of most of the practical automatic controllers rely on a simplified model of the irrigation canal. This model can be obtained from measured data (identification) or can be formulated (white box models) assuming simplifications in the physical concepts and using the canal geometry. Several models of this kind are presently available. Moreover, short canals reveal a resonance problem, due to the back and forth of waves. This paper is focused on how to choose a suitable model for short canal pools with the purpose of control design. Four simple models are applied to two different types (resonant and non-resonant) of short canals: First order transfer function based on the Hayami model, Muskingum model, Integrator Delay (ID), and Integrator Delay plus Zero (IDZ). Model predictive controllers are developed based on these models and they are tested numerically and experimentally in order to evaluate their contribution to the control effectiveness. The controllers based on the ID and IDZ model showed the best performance. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
15. Non-negative depth reconstruction for a two-dimensional partial inertial inundation model.
- Author
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Hongbin Zhang, Yueling Wang, Qiuhua Liang, Smith, Luke S., and Kilsby, Chris G.
- Subjects
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NUMERICAL analysis , *PERFORMANCE evaluation , *CONTINUITY , *WATER depth , *HYDRODYNAMICS , *HYDRAULIC models - Abstract
This paper proposes a non-negative depth reconstruction method for improving the numerical performance of a partial inertial model (PIM) for applications involving steep-slope and low-friction conditions. The PIM solves the continuity equation of two-dimensional (2D) shallow water equations (SWEs) with the interface fluxes evaluated by a simplified momentum equation that partially restores the inertial terms. In applying the PIM to flood simulations, a practical challenge is to represent complex topography and to track the moving wet-dry interface without resulting in negative water depths. Another challenge is to avoid the numerical issue caused by the lack of physical diffusive terms when it is applied to low-friction cases. To cope with these difficulties, the PIM is improved by introducing a non-negative depth reconstruction method, featuring two different ways for calculating the interface fluxes. The performance of the improved PIMs is investigated through applications to several theoretical and practical benchmark test cases. The comparison of the numerical results against analytical solutions or predictions from the original PIM and a full 2D finite-volume hydrodynamic model shows that the proposed reconstruction method can avoid non-negative water depth predictions, and improve the numerical performance of the original PIM when applied to steep-slope and low-friction conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
16. An appraisal of the performance of data-infilling methods for application to daily mean river flow records in the UK.
- Author
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Harvey, Catherine L., Dixon, Harry, and Hannaford, Jamie
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STREAMFLOW , *PERFORMANCE evaluation , *DATA analysis , *HYDRAULIC measurements , *MISSING data (Statistics) , *TIME series analysis - Abstract
River flow records are fundamental for the sustainable management of water resources and even very short gaps can severely compromise their utility. Suitably-flagged flow estimates, derived via judicious infilling, are potentially highly beneficial to data users. The UK National River Flow Archive provides stewardship of, and access to, UK river flow records. While many datasets held on the archive are complete, gaps remain across a wide range of flow records. A comprehensive assessment of existing techniques for infilling these gaps is currently lacking. This paper therefore assesses 15 simple infilling techniques (including regression, scaling and equipercentile approaches), each relying upon data transfer from hydrologically-similar donor stations, to generate estimates of flow at 26 representative gauging stations. Results reveal the overall superiority of equipercentile and multiple regression techniques compared to the poorer capability of catchment area scaling. Donor station choice has a strong influence on technique performance. Modifying datasets to improve homogeneity, by seasonally grouping flows or excluding certain periods, offers improved performance. These findings provide a foundation upon which guidance on infilling river flow records can be based in future, allowing hydrometric practitioners and data end-users alike to adopt a consistent and auditable approach towards infilling. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
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17. A performance indicators system for urban wastewater treatment plants.
- Author
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Quadros, Sílvia, Rosa, Maria João, Alegre, Helena, and Silva, Catarina
- Subjects
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KEY performance indicators (Management) , *SEWAGE disposal plants , *PERFORMANCE evaluation , *ENVIRONMENTAL policy , *WATER reuse , *POLLUTANTS , *MANAGEMENT - Abstract
A performance assessment system (PAS) is an important instrument to provide a cost-effective and sustainable management of wastewater treatment plants (WWTPs). Despite the fact that many PASs have been developed in recent years, important aspects of WWTP evaluation have not yet been considered. This paper presents the framework and the overall performance indicators of a PAS developed for urban WWTPs. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
18. Technology selection and comparative performance of source-separating wastewater management systems in Sweden and The Netherlands.
- Author
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Mels, A., Van Betuw, W., and Braadbaart, O.
- Subjects
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GRAYWATER (Domestic wastewater) , *WASTEWATER treatment , *SEWAGE purification , *SANITATION , *PERFORMANCE evaluation , *URINE , *PILOT projects - Abstract
The research described in this paper has evaluated five demonstration projects with source-separating sanitation at neighbourhood scale, 10 years or more after their establishment. It presents the results of two systems with local grey water treatment in The Netherlands and three sites with urine separation in Sweden. The study has focused on (1) the drivers and barriers of the stakeholders that were responsible for project implementation and (2) the comparative performance of the source separation systems after their establishment. In The Netherlands the main drivers were water use reduction, combating sewer overflows and reduction of emissions. For the Swedish cases the main drivers of the involved actors were nutrient recycling, emission reduction and an active policy of the local government. The main barriers in all cases were higher investment costs and low experience with new sanitation approaches systems compared with the conventional system. Three of the sites showed a lower performance with respect to public health because effluent monitoring protocols for the grey water treatment systems were not in place or people could have direct contact with faeces. Lack of operation and maintenance is a cause of occasional failure for the grey water treatment systems, while the dominant failure reason for the urine separation systems was pipe clogging. The inventory showed that source-separating sanitation systems have a high potential to save or recover resources (water and nutrients). [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
19. Temperature and conductivity as control parameters for pollution-based real-time control.
- Author
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Schilperoort, R. P. S., Gruber, G., Flamink, C. M. I., Clemens, F. H. L. R., and Van der Graaf, J. H. J. M.
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PERFORMANCE evaluation , *SEWAGE disposal plants , *STATISTICAL correlation , *SEWAGE purification , *REAL-time control , *PLANT monitoring , *MONITORING of water-pipes - Abstract
Most sewer system performance indicators are not easily measurable online at high frequencies in wastewater systems, which hampers real-time control with those parameters. Instead of using a constituent of wastewater, an alternative could be to use characteristics of wastewater that are relatively easily measurable in sewer systems and could serve as indicator parameters for the dilution process of wastewater. This paper focuses on the possibility to use the parameters of temperature and conductivity. It shows a good relation of temperature and conductivity with the dilution of DWF (dry weather flow) during WWF (wet weather flow) a monitoring station in Graz, Austria, as an example. The simultaneous monitoring of both parameters leads to valuable back-up information in case one parameter (temperature) shows no reaction to a storm event. However, for various reasons, anomalies occur in the typical behaviour of both parameters. The frequency and extent of these anomalies will determine the usefulness of the proposed parameters in a system for pollution-based real-time control. Both the normal behaviour and the anomalies will be studied further by means of trend and correlation analyses of data to be obtained from a monitoring network for the parameters of interest that is currently being set up in the Netherlands. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
20. Hybrid metaheuristics for multi-objective design of water distribution systems.
- Author
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Qi Wang, Savić, Dragan A., and Kapelan, Zoran
- Subjects
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METAHEURISTIC algorithms , *WATER distribution , *EVOLUTIONARY algorithms , *INDUSTRIAL costs , *PERFORMANCE evaluation , *WATER supply - Abstract
Multi-objective design of Water Distribution Systems (WDSs) has received considerable attention in the past. Multi-objective evolutionary algorithms (MOEAs) are popular in tackling this problem due to their ability to approach the true Pareto-optimal front (PF) in a single run. Recently, several hybrid metaheuristics based on MOEAs have been proposed and validated on test problems. Among these algorithms, AMALGAM and MOHO are two noteworthy representatives which mix their constituent algorithms in contrasting fashion. In this paper, they are employed to solve a wide range of benchmark design problems against another state-of-the-art algorithm, namely NSGA-II. The design task is formulated as a bi-objective optimisation problem taking cost and network resilience into account. The performance of three algorithms is assessed via normalised hypervolume indicator. The results demonstrate that AMALGAM is superior to MOHO and NSGA-II in terms of convergence and diversity on the networks of small-to-medium size; however, for larger networks, the performance of hybrid algorithms deteriorates as they lose their adaptive capabilities. Future improvement and/or redesign on hybrid algorithms should not only adopt the strategies of adaptive portfolios of subalgorithms and global information sharing, but also prevent the deterioration mainly caused by imbalance of constituent algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
21. Using economic and other performance measures to evaluate a municipal drought plan.
- Author
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Yates, David N., Vásquez Lavin, Felipe, Purkey, David P., Guerrero, Santiago, Hanemann, Michael, and Sieber, Jack
- Subjects
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DROUGHTS , *PERFORMANCE evaluation , *CLIMATE change , *MUNICIPAL water supply , *WATER power - Abstract
This paper explores the welfare costs associated with drought plan transactions between a public municipal water agency, the El Dorado Irrigation District (EID) in California in the USA and its customers. The EID imposes a tiered pricing plan for municipal customers, which was analyzed as a discrete continuous choice (DCC) model by water users within a climate driven water evaluation and planning (WEAP) model of the EID water system. The DCC is subsequently used to estimate the compensating variation (CV) measure of the loss of consumer welfare in the case where a customer does not receive water that matches a preferred level of demand. In addition to monetized welfare loss, we look at other metrics of performance such as reservoir storage and hydropower generation. For the drought-of-record under full build-out, results show that the welfare loss to EID customers from the imposed drought plan is far less than if no drought plan were in place. This suggests that current consumption is well beyond essential needs and, without a drought plan, water shortages in the later period of a drought would generate a much greater welfare loss. Most of the cost associated with the drought plan is born by EID in the form of reduced revenues. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
22. An improved numerical scheme for the approximate solution of the Parabolic Wave model.
- Author
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Cimorelli, Luigi, Cozzolino, Luca, Della Morte, Renata, and Pianese, Domenico
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NUMERICAL analysis , *APPROXIMATION theory , *PERFORMANCE evaluation , *MATHEMATICAL models , *ALGORITHMS , *COMPUTATIONAL fluid dynamics , *PROBLEM solving - Abstract
In this paper, the main features and performances of a new numerical scheme, ILILPM (Improved Locally and Instantaneously Linearized Parabolic Model) are described. ILILPM is an improved version of the Parabolic and Backwater (PAB) and Linearized Parabolic Model (LPM) schemes, proposed in literature for the approximate solution of the Parabolic Wave model. The algorithm presented is able to take into account transcritical flow regime and transitions from free-surface to pressurized flow in tree-like channel networks. Due to its unconditional stability, the model allows large computational time steps, leading to very fast simulations during transients for a class of flow conditions larger than those solved by the parent schemes. The model is demonstrated by comparing its results with experimental observations and with the results provided by the numerical solution of the full De Saint-Venant equations. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
23. An electromagnetic-based method for pinpointing leaks in buried pipes: a practical validation.
- Author
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Cataldo, A., Cannazza, G., De Benedetto, E., Miraglia, M., Ancora, D., and Giaquinto, N.
- Subjects
WATER leakage -- Management ,ELECTROMAGNETISM ,BURIED pipes (Engineering) ,TIME-domain reflectometry ,UNDERGROUND pipelines ,FAULT tolerance (Engineering) ,PERFORMANCE evaluation - Abstract
In this paper, a time domain reflectometry (TDR)-based solution for detecting water leaks in underground pipes is described and experimentally validated. The proposed method strongly reduces the inspection time that is typically required by traditional leak detection methods. In fact, it can successfully inspect pipes that are hundreds of meters long. In this work, two different configurations of the system are described: one can be used for detecting leaks in 'already-installed' metal pipes; whereas the other is suitable to be employed for detecting leaks in 'newly-installed' pipes made of any material. The performance of both these system configurations was assessed through an extensive, on-site experimental campaign, carried out with the collaboration of one of the largest European water operators, Acquedotto Pugliese S.p.A. (AQP). Representative results, related to both configurations, of three experimental cases (ECs) are reported and commented on. Finally, some practical considerations on the applicability of the system are provided. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
24. Distributed tree-based model predictive control on a drainage water system.
- Author
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Maestre, J. M., Raso, L., Van Overloop, P. J., and De Schutter, B.
- Subjects
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DRAINAGE , *PREDICTIVE control systems , *STOCHASTIC programming , *WEATHER forecasting , *MATHEMATICAL optimization , *PREDICTION models , *PERFORMANCE evaluation - Abstract
Open water systems are one of the most externally influenced systems due to their size and continuous exposure to uncertain meteorological forces. The control of systems under uncertainty is, in general, a challenging problem. In this paper, we use a stochastic programming approach to control a drainage system in which the weather forecast is modeled as a disturbance tree. Each branch of the tree corresponds to a possible disturbance realization and has a certain probability associated to it. A model predictive controller is used to optimize the expected value of the system variables taking into account the disturbance tree. This technique, tree-based model predictive control (TBMPC), is solved in a distributed fashion. In particular, we apply dual decomposition to get an optimization problem that can be solved by different agents in parallel. In addition, different possibilities are considered in order to reduce the communicational burden of the distributed algorithm without reducing the performance of the controller significantly. Finally, the performance of this technique is compared with others such as minmax or multiple MPC. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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25. Using high performance techniques to accelerate demand-driven hydraulic solvers.
- Author
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Guidolin, Michele, Kapelan, Zoran, and Savić, Dragan
- Subjects
- *
HIGH performance computing , *PERFORMANCE evaluation , *HYDRAULIC models , *WATER distribution , *SIMD (Computer architecture) , *LINEAR algebra - Abstract
Computer models of water distribution networks are commonly used to simulate large systems under complex dynamic scenarios. These models normally use so-called demand-driven solvers, which determine the nodal pressures and pipe flow rates that correspond to specified nodal demands. This paper investigates the use of data parallel high performance computing (HPC) techniques to accelerate demand-driven hydraulic solvers. The sequential code of the solver implemented in the CWSNet library is analysed to understand which computational blocks contribute the most to the total computation time of a hydraulic simulation. The results obtained show that, contrary to popular belief, the linear solver is not the code block with the highest impact on the simulation time, but the pipe head loss computation. Two data parallel HPC techniques, single instruction multiple data (SlMD) operations and general purpose computation on graphics processing units (GPGPU), are used to accelerate the pipe head loss computation and linear algebra operations in new implementations of the hydraulic solver of CWSNet library. The results obtained on different network models show that the use of this techniques can improve significantly the performance of a demand-driven hydraulic solver. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
26. Characterization and predicting DOM treatability by enhanced coagulation.
- Author
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Dongsheng Wang, Jiankun Xie, Chow, Chris W. K., Linan Xing, and van Leeuwen, John
- Subjects
ORGANIC compounds removal (Water purification) ,COAGULATION in water purification ,FOAM fractionation (Water purification) ,QUANTITATIVE chemical analysis ,POLYALUMINUM chloride ,PERFORMANCE evaluation - Abstract
The dissolved organic matter (DOM) plays significant role in water safety due to not only the natural occurrence but also man-induced pollution. To characterize and predict DOM treatability becomes therefore a very important and hot topic. In this paper, enhanced coagulation by four typical coagulants (FeCl
3 , Al2 (SO4 )3 , polyaluminum chloride (PAC) and high performance polyaluminum chloride (HPAC)) without pH control was characterized using the chemical fractionation (resin adsorption, RA) and physical fractionation (high performance size exclusion chromatography (HPSEC) combined with peak fitting technique). The results show that the DOM removal can be separated into two stages, rapid removal and continual slow removal. The PAC exhibits efficient removal in the rapid part while the traditional salts are more efficient in the latter part. It is also very important for pH control to improve DOM removal by the traditional coagulants. DOM treatability per unit dosage (1 x 10-4 mol/l) for the four coagulants was then calculated in the order of HPAC (26.0%)>PAC (17.3%)> FeCl3 (14.3%)>Al2 (SO4 )3 (12.0%). Two sets of DOM treatability models, i.e. removal efficiency, for enhanced coagulation of the four coagulants were developed by combining the chemical and physical DOM fractions based on the quantitative analysis of the removal state of raw water. The two sets of models could be transformed to each other. The composition of the removable DOM by enhanced coagulation of the four coagulants was revealed and validated using 29 raw waters (in 13 source waters in three seasons), and as a result the low deviation indicated that the predicted data matched well with the actual data. It provided the possibility for the application in practical operation of water plant. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
27. Spatial network generation tool for water distribution network design and performance analysis.
- Author
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Trifunović, Nemanja, Maharjan, Bharat, and Vairavamoorthy, Kalanithy
- Subjects
SPATIAL systems ,WATER distribution ,PERFORMANCE evaluation ,GRAPH theory ,RANDOMIZED response ,ROBUST control - Abstract
The research presented in this paper aims at the support tool for generation of multiple networks with preset or randomised properties. To explore particular phenomena, water distribution analysis may require a coherent set of cases. Readily available in the literature are simple synthetic networks used for benchmarking, either real-life cases that are too diverse in size and configuration. The network generation tool (NGT) developed on the principles of graph theory connects any seed of nodes prepared in EPANET modelling software, by avoiding pipe crossings or unnecessary duplications. The pipe properties can be assigned by specifying a range of arbitrary lengths and diameters, by using coordinates to calculate the lengths, or by genetic algorithm optimisation of initial diameters. Equally, the nodal elevations and demands are arbitrarily assigned when not predefined in EPANET. Several sets of networks have been generated, up to 200 junctions. To test robustness of the tool, 13,000 layouts of a 50-junction seed have been generated using different settings. NGT has been proven to be capable of executing this task mostly within a few minutes, producing network layouts that resemble those from practice. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
28. Return of drinking water supply in Paris to public control.
- Author
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Barraqué, Bernard
- Subjects
- *
DRINKING water , *WATER supply , *PUBLIC-private sector cooperation , *PUBLIC administration , *PERFORMANCE evaluation , *MUNICIPAL services - Abstract
The 'reclaiming' by Paris of its water back into public hands is a paradox in the homeland of transnational water companies and at a time when the European Commission rather favours the liberalisation of public services 'of general economic interest'. Yet what has happened is more complex. A quick historical review of management formulas in Europe reveals both the specific model of delegation to private companies made in France, and also the maintained direct labour management formula (with direct public procurement by municipalities) used in several French cities to be presented. Paris has a long history of public procurement of water, whilst using a private company for metering and billing customers. Mayor Chirac changed to a semi-public company with public production and private distribution contracted out to two private companies (with responsibility for the fight and left banks). Mayor Delanoë managed to reclaim the distribution in a commercial but public institution called an Établissement Public à caractère Industriel et Commercial (EPIC); this had unsuspected impacts on water supply issue in the suburbs. While Paris can obviously run its services directly, the emerging issue appears to be multi-level governance at the metropolitan level, rather than just a public-private debate. This paper also discusses in detail the arguments put forward by Anne le Strat, Deputy Mayor for Water, in favour of returning to public control, and presents the difficulties of assessing the performance of a service operator, under both delegation and direct management. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
29. Development of an integrated computational tool to improve performance of irrigation districts.
- Author
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Urrestarazu, L. Pérez, Díaz, J. A. Rodríguez, Poyato, E. Camacho, Luque, R. López, and Jaraba, F. M. Borrego
- Subjects
- *
IRRIGATION districts , *EXECUTIVES , *HYDRAULIC models , *GEOGRAPHIC information systems , *WATER distribution , *PERFORMANCE evaluation - Abstract
Nowadays irrigation district managers require several tools to assess irrigation networks' performance such as hydraulic models, geographic information systems (GIS) or decision support systems (DSS) which are available but as independent elements. Thus, simplifying the use of these tools by means of applications that integrate all these components would be helpful for irrigation district managers. In this paper, a computer tool combining a GIS, a hydraulic model and performance indicators (PIs) has been developed creating a database to deal with most information required in an irritation district. MapObjects Java Edition was used for the GIS integration and EPANET calculation module for the hydraulic modeling. This tool enables the study of the network performance, taking into account real measures (data from the remote control system) and simulated measures (obtained when running the hydraulic model) which are stored in a database and used to calculate different indicators that can be represented in the GIS. The PIs calculated with this tool give important information regarding the network response to different conditions, malfunction problems and failures in supply. Therefore, this tool is also useful to study the effects of improvements and the quality of service provided to farmers. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
30. Hydraulic performance analysis of sewer systems with uncertain parameters.
- Author
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Hosseini, Seyed Mahmood and Ghasemi, Ali
- Subjects
- *
FUZZY logic , *HYDRAULICS , *SEWERAGE , *PARAMETER estimation , *SANITARY sewer overflow , *PERFORMANCE evaluation , *UNCERTAINTY - Abstract
In this paper, a exible fuzzy model is proposed for the hydraulic performance analysis of separate domestic sewer systems. In the proposed model, all modeling outputs such as discharge, velocity and depth are developed as fuzzy numbers by taking into account all the available information and expert knowledge about the basic design/analysis parameters. The fuzzy outputs are then combined with performance assessment curves to calculate the hydraulic performance values. The proposed model was applied to a part of the sewer system of a city in Iran, and performance graphs were plotted. Such graphs can be used by design engineers and operation managers to improve the design quality, reliability and the performance of a system with uncertain parameters. The analysis results can also be used in decision-making and identifying priorities to develop rehabilitation strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
31. Results of 'PASt21' -- the Portuguese initiative for performance assessment of water and wastewater treatment plants.
- Author
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Silva, C., Ramalho, P., Quadros, S., Alegre, H., and Rosa, M. J.
- Subjects
SEWAGE disposal plants ,KEY performance indicators (Management) ,WATER treatment plants ,PERFORMANCE evaluation ,WATER supply - Abstract
Performance assessment of water supply and wastewater services is today a major issue. Over the past six years, the National Civil Engineering Laboratory (Portugal) has been developing performance assessment systems for drinking water treatment plants (WTPs) and wastewater treatment plants (WWTPs). In 2009, a national field-test was launched in Portugal, 'PASt21', involving 27 plants (10 WTPs and 17 WWTPs). This paper presents an overview of the second generation of the performance indicator (PI) systems for the overall performance assessment of WTPs and WWTPs, the extent to which the systems were applied in the 5-year study period (2006--2010), and the aggregated results (average, median, percentiles 25 and 75, maximum and minimum) of representative PIs in each assessment group. It was concluded that all indicators are relevant, and the results show the ability of the proposed PI systems to assess the overall performance of a given treatment plant. The aggregated results are very important for the continuous improvement of the plant performance through benchmarking and periodic reassessment of targets. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
32. Monthly groundwater level prediction using ANN and neuro-fuzzy models: a case study on Kerman plain, Iran.
- Author
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Jalalkamali, Amir, Sedghi, Hossein, and Manshouri, Mohammad
- Subjects
- *
WATER table , *FUZZY systems , *MATHEMATICAL models , *CASE studies , *GROUNDWATER management , *ARTIFICIAL neural networks , *PERFORMANCE evaluation , *RIVERS - Abstract
The prediction of groundwater levels in a well has immense importance in the management of groundwater resources, especially in arid regions. This paper investigates the abilities of neuro-fuzzy (NF) and artificial neural network (ANN) techniques to predict the groundwater levels. Two different NF and ANN models comprise various combinations of monthly variablities, that is, air temperature, rainfall and groundwater levels in neighboring wells. The result suggests that the NF and ANN techniques are a good choice for the prediction of groundwater levels in individual wells. Also based on comparisons, it is found that the NF computing techniques have better performance than the ANN models in this case. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
33. Mathematical modelling of a hydraulic controller for PRV flow modulation.
- Author
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AbdelMeguid, Hossam, Skworcow, Piotr, and Ulanicki, Bogumil
- Subjects
- *
MATHEMATICAL models , *HYDRAULIC engineering , *VALVES , *CALIBRATION , *PERFORMANCE evaluation , *INTEGRATED software , *SIMULATION methods & models , *NUMERICAL analysis - Abstract
This paper describes the development of mathematical models, which represent static and dynamic properties of the AQUAI-MOD® hydraulic controller coupled with a standard pressure reducing valve (PRV) as well as a new experimental set-up for testing the controller and calibrating and validating the models. The purpose of the AQUAI-MOD® controller is to modulate the PRV outlet pressure according to the valve flow. The controller has been experimentally tested to assess its operation in different conditions and operating ranges and in all cases showed good performance. The mathematical models of the PRV and its controller have been developed and solved using the Mathematica software package to represent both steady state and dynamics conditions. The numerical results of simulation of the mathematical model have been compared with experimental data and showed a good agreement in magnitude and trends. The model can be used to simulate the behaviour of the PRV and the AQUAI-MOD® hydraulic controller in typical network applications. It can also be used at the design stage to size the controller components and to compute the required set points for the minimum and the maximum pressure before installing the controller in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
34. Improved real-time data anomaly detection using context classification.
- Author
-
Branisavćljevic, Nemanja, Kapelan, Zoran, and Prodanović, Dušan
- Subjects
- *
REAL-time computing , *ANOMALY detection (Computer security) , *CLASSIFICATION , *WATER , *SEWER pipes , *ACQUISITION of data , *SUPERVISORY control systems , *PERFORMANCE evaluation , *DATA mining - Abstract
The number of automated measuring and reporting systems used in water distribution and sewer systems is dramatically increasing and, as a consequence, so is the volume of data acquired. Since real-time data is likely to contain a certain amount of anomalous values and data acquisition equipment is not perfect, it is essential to equip the SCADA (Supervisory Control and Data Acquisition) system with automatic procedures that can detect the related problems and assist the user in monitoring and managing the incoming data. A number of different anomaly detection techniques and methods exist and can be used with varying success. To improve the performance, these methods must be fine tuned according to crucial aspects of the process monitored and the contexts in which the data are classified. The aim of this paper is to explore if the data context classification and pre-processing techniques can be used to improve the anomaly detection methods, especially in fully automated systems. The methodology developed is tested on sets of real-life data, using different standard and experimental anomaly detection procedures including statistical, model-based and data-mining approaches. The results obtained clearly demonstrate the effectiveness of the suggested anomaly detection methodology. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
35. Reliability assessment of water distribution systems with statistical entropy and other surrogate measures.
- Author
-
Tanyimboh, Tiku T., Tietavainen, Marika T., and Saleh, Saleh
- Subjects
RELIABILITY in engineering ,WATER distribution ,ENTROPY ,PERFORMANCE evaluation ,WATERWORKS ,FAULT tolerance (Engineering) ,COST - Abstract
There is ever increasing commercial and regulatory pressure to minimise the cost of water distribution networks even as the demand for them keeps on growing. But cost minimizing is only one of the demands placed on network design. Satisfactory networks are required to operate above a minimum level even if they experience failure of components. Reliable hydraulic performance can be achieved if sufficient redundancy is built in the network. This has given rise to various water distribution system optimization methods including genetic algorithms and other evolutionary computing methods. Evolutionary computing approaches frequently assess the suitability of enormous numbers of potential solutions for which the calculation of accurate reliability measures could be computationally prohibitive. Therefore, surrogate reliability measures are frequently used to ease the computational burden. The aim of this paper is to assess the correlation of surrogate reliability measures in relation to more accurate measures. The surrogate measures studied are statistical entropy, network resilience, resilience index and modified resilience index. The networks were simulated with the prototype software PRAAWDS that produces more realistic results for pressure-deficient water distribution systems. Statistical entropy outperformed resilience index in this study. The results also demonstrate there is a strong correlation between entropy and failure tolerance. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
36. Performance analysis in water distribution
- Author
-
Alegre, H. and Coelho, S. T.
- Abstract
The level of service provided by water supply and distribution systems is one of the key issues facing the water industry today. However,measuring the performance and assessing the level of service provided by a water distribution network are not straightforward tasks, given the multiple factors and viewpoints involved, and the lack of a unified approach or a single clear-cut definition of performance. This paper addresses the engineering side of the problem, by using a flexible framework based on an array of performance indices. The Performance Evaluation System developed is a technical analysis tool, designed to shift the focus of management and operations of water systems to awider more rigorous, performance-orientated view. It is based on a system of penalty curves, flexible enough to accommodate individual sensitivities and interpretations. The methodology allows for a rapid gain in sensitivity to the network's behaviour, providing a standardised means of diagnosis, and is a valuable aid for planning, design, operation and rehabilitation of water distribution systems. [ABSTRACT FROM AUTHOR]
- Published
- 1998
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