Author: Timothy J. Karikari
Publisher:
ISBN:
Category :
Languages : en
Pages : 81

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Book Description

Author: HAIWEN GAO
Publisher:
ISBN:
Category :
Languages : en
Pages : 289

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Book Description
Secondary settling tanks (SSTs) are a very crucial process that determines the performance of the activated sludge process (ASP). Due to the importance of its performance, computational fluid dynamics (CFD) models have been employed for the designing new SSTs, the modifying the geometries of existing SSTs and improving control techniques in wastewater treatment plants. However, the practical application of SST CFD models remains challenges due to several difficulties, such as the uncertainty of model structures and the accuracy of different sub-models. To facilitate the practical application of CFD SST models, this dissertation focuses on the numerical analysis of SST models, including the evaluation of different turbulence sub-models and investigation the impact of different parameters in modeling structures and the application of CFD models on the design and operation of SSTs, including improving the understanding the effects of different operation parameters, and surface wind conditions on the performance of SSTs. To improve the understanding of CFD modeling of SSTs, this dissertation provides a comprehensive literature review of different multiphase approaches and the widely applied single-phase approach to model the motion of the particle in SSTs. The literature review also provides a thorough introduction of current CFD research and engineering practice, focusing on the formation and the effect of density currents, effects of different design variables, parameter uncertainties in modeling structures and atmospheric conditions. Also, the widely applied standard k- (SKE) turbulence sub-model is investigated with two more advanced turbulence models (RNG k- and Realizable k- models). The results show that turbulence sub-model selection has a strong influence on the prediction of hydrodynamics of an SST, especially inside the inlet zone, and on the prediction of flow capacity. Moreover, due to the inconsistency of coupling or decoupling the buoyancy-term in the turbulence model structure among different studies as well as the discrepancies observed in other modeling structures, including in the sludge transport model, sludge settling model, dry solids density and different inlet turbulence boundary conditions, their impact on the prediction accuracy of an SST are all investigated. This dissertation also investigates CFD applications on the design and operation of SSTs, including improving the understanding of the effects of different operation parameters, and surface wind conditions on the performance of SSTs. The effects of different operation parameters, such as surface overflow rate (SOR), sludge loading rate (SLR), the concentration of mixed liquid suspended solids (MLSS), and returned activated sludge (RAS) concentration, are firstly evaluated with professor McCorquodale's Quasi-3D SST model. Next, the operational strategy to these operating parameters is investigated with Ansys Fluent-based model in order to maximize the SST capacity. The maximum capacity predicted by the Fluent-based CFD model is then compared with the prediction of one-dimensional idealized flux theory (1DFT) model. Also, the performance of the McKinney baffle on the SST performance is evaluated and shows significant improvement on the SST performance. Finally, instead of focusing on the influential factors inside SSTs, the effects of wind on the performance of both circular and rectangular SSTs are studied. Due to the strong negative impact of wind on the SST performance, the prediction results suggest that in strong windy climates covering SSTs or protecting them from strong winds may be justified.

Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1468451979
Category : Science
Languages : en
Pages : 407

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Book Description
Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 29 (thesis year 1984) a total of 12,637 theses titles from 23 Canadian and 202 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 29 reports theses submitted in 1984, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.

Author: G. A. Ekama
Publisher: International Water Assn
ISBN: 9781900222037
Category : Science
Languages : en
Pages : 216

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Book Description
The secondary settling tank (SST) plays a major ro

Author: Jacek Makinia
Publisher: IWA Publishing
ISBN: 1780409516
Category : Science
Languages : en
Pages : 682

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Book Description
Mathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and the latest developments in modelling the innovative nitrogen removal processes. Furthermore, a new section on micropollutant removal has been added. The focus of modelling has been shifting in the last years to models that can describe the performance of a whole plant (plant-wide modelling). The expanded part of this new edition introduces models describing the most important processes interrelated with the mainstream activated sludge systems as well as models describing the energy balance, operating costs and environmental impact. The complex process evaluation, including minimization of energy consumption and carbon footprint, is in line with the present and future wastewater treatment goals. By combining a general introduction and a textbook, this book serves both intermediate and more experienced model users, both researchers and practitioners, as a comprehensive guide to modelling and simulation studies. The book can be used as a supplemental material at graduate and post-graduate levels of wastewater engineering/modelling courses.

Author: Maria Carmo Nicoletti
Publisher: Springer Science & Business Media
ISBN: 3642018874
Category : Mathematics
Languages : en
Pages : 349

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Book Description
Computational Intelligence (CI) and Bioprocess are well-established research areas which have much to offer each other. Under the perspective of the CI area, Biop- cess can be considered a vast application area with a growing number of complex and challenging tasks to be dealt with, whose solutions can contribute to boosting the development of new intelligent techniques as well as to help the refinement and s- cialization of many of the already existing techniques. Under the perspective of the Bioprocess area, CI can be considered a useful repertoire of theories, methods and techniques that can contribute and offer interesting alternative approaches for solving many of its problems, particularly those hard to solve using conventional techniques. Although throughout the past years CI and Bioprocess areas have accumulated substantial specific knowledge and progress has been quick and with a high degree of success, we believe there is still a long way to go in order to use the potentialities of the available CI techniques and knowledge at their full extent, as tools for supporting problem solving in bioprocesses. One of the reasons is the fact that both areas have progressed steadily and have been continuously accumulating and refining specific knowledge; another reason is the high level of technical expertise demanded by each of them. The acquisition of technical skills, experience and good insights in either of the two areas is very demanding and a hard task to be accomplished by any professional.

Author: Jyeshtharaj Joshi
Publisher: Woodhead Publishing
ISBN: 0081023375
Category : Science
Languages : en
Pages : 888

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Book Description
Advances of Computational Fluid Dynamics in Nuclear Reactor Design and Safety Assessment presents the latest computational fluid dynamic technologies. It includes an evaluation of safety systems for reactors using CFD and their design, the modeling of Severe Accident Phenomena Using CFD, Model Development for Two-phase Flows, and Applications for Sodium and Molten Salt Reactor Designs. Editors Joshi and Nayak have an invaluable wealth of experience that enables them to comment on the development of CFD models, the technologies currently in practice, and the future of CFD in nuclear reactors. Readers will find a thematic discussion on each aspect of CFD applications for the design and safety assessment of Gen II to Gen IV reactor concepts that will help them develop cost reduction strategies for nuclear power plants. Presents a thematic and comprehensive discussion on each aspect of CFD applications for the design and safety assessment of nuclear reactors Provides an historical review of the development of CFD models, discusses state-of-the-art concepts, and takes an applied and analytic look toward the future Includes CFD tools and simulations to advise and guide the reader through enhancing cost effectiveness, safety and performance optimization

Author: Ben Li
Publisher:
ISBN:
Category :
Languages : en
Pages : 240

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Book Description
Sedimentation is one of the most important processes that determine the performance of the activated sludge process, and secondary settling tanks (SSTs) have been investigated with the mathematical models for design and operation optimization. However, the practical application of SST models still remains a challenge due to several difficulties, such as the lack of efficient (high accuracy and low computation cost) solution techniques and reliable model calibration strategies. To facilitate the practical application of SST models, this dissertation focuses on the one-dimensional (1-D) modeling of SSTs, including the numerical analysis to introduce and select efficient solution techniques, sensitivity and practical identifiability analysis to reliably calibrate the 1-D SST models, and evaluation of the implications of SST modeling on the design and control of waste water treatment plants. To improve the understanding of 1-D modeling of SSTs, this dissertation provides a comprehensive literature review of the batch settling methodology and the flux theory, which played a significant role in the early stage of SST investigation. The literature review also contains an explicit introduction of the established 1-D SST models, including the relevant physical laws, various settling behaviors, the constitutive functions, available solution techniques and calibration strategies. As the only available method for analytical solution development of ideal continuous settling model, the method of characteristics has been successfully implemented to investigate the dynamics of SST for various solids loading conditions. This dissertation also introduced the Yee-Roe-Davis method, which able to capture solution discontinuities based on gradient, thus providing numerical solutions with second-order accuracy. By using the method of characteristics as a reference, the convergence analysis of Methods Simplified-Godunov, Godunov and Yee-Roe-Davis shows that all are reliable, since they are able to provide arbitrarily close approximations to the reference solutions as discretization is refined. For a given discretization level, the Yee-Roe-Davis method is most efficient in reducing error, and provides the most accurate approximations. However, this advantage of high accuracy of the Yee-Roe-Davis method is at the cost of larger computation time and coding complexity. To facilitate model calibration, the important parameters for 1-D SST model calibration were identified under non-ideal flow and settling conditions using global sensitivity analysis (GSA). This dissertation also demonstrated that reliable reduction of 1-D SST models can be achieved based on GSA results; for example under the bulking condition, the hindered-compression-dispersion model can be reduced to the hindered-dispersion model without impacting model accuracy. The model uncertainty analysis efficiently evaluates model reduction reliability. In terms of developing batch settling methodology for reliable model calibration, this dissertation found that the hindered settling parameters are more influential in situations where only batch settling data are available, while the sensitivity to compression parameters can be greatly increased if concentration profile observations are included. The practical identifiability analysis further showed that parameter estimates obtained from data sets that only include batch settling data or the concentration profiles cannot generally predict concentration profiles and batch settling curve observations, respectively. Because of the application of local sensitivity functions, the parameter identifiability analysis can be sensitive to the initial parameter value selection. Estimates obtained by identifiable parameter subsets estimation are conditional on the values of fixed parameters. From the view of optimizing the process design and control, this dissertation demonstrated that the bioreactor and SST should be designed as a whole, and a safety constraint can be introduced in the design process to greatly improve the system's efficiency and reliability. A comprehensive selection of the designed alternatives should consider three aspects: economic plausibility, contaminant removal efficiency, and system robustness. Least-cost points can usually be attained, but their locations will vary depending on the weighting of the relative cost factor.

Author: Xiaofeng Liu
Publisher:
ISBN: 9780784415313
Category : Computational fluid dynamics
Languages : en
Pages : 186

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Book Description
This book provides an introduction, overview, and specific examples of computational fluid dynamics and their applications in the water, wastewater, and stormwater industry.

Author: Shie-yui Liong
Publisher: World Scientific
ISBN: 9814483028
Category : Technology & Engineering
Languages : en
Pages : 2073

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Book Description
Hydroinformatics addresses cross-disciplinary issues ranging from technological and sociological to more general environmental concerns, including an ethical perspective. It covers the application of information technology in the widest sense to problems of the aquatic environment.This two-volume publication contains about 250 high quality papers contributed by authors from over 50 countries. The proceedings present many exciting new findings in the emerging subjects, as well as their applications, such as: data mining, data assimilation, artificial neural networks, fuzzy logic, genetic algorithms and genetic programming, chaos theory and support vector machines, geographic information systems and virtual imaging, decision support and management systems, Internet-based technologies.This book provides an excellent reference to researchers, graduate students, practitioners, and all those interested in the field of hydroinformatics.