Coupling Hydrodynamic and Biokinetic Growth Models in Aerated Wastewater Treatment Processes

In this thesis, a coupled hydrodynamic and wastewater biokinetic finite volume based CFD model for an aeration tank in OpenFOAM has been created to understand the effect of the hydrodynamics on the biological processes. A pilot-scale aeration tank that is aerated using fine membrane diffusers along the base has been designed and manufactured. A procedure for conducting lab experiments using an acoustic Doppler velocimeter to record velocity measurements was outlined. A series of aeration tank experiments with flow rates ranging from 18 – 108 L/min through membrane diffuser setups that involved 1 or 3 diffusers were conducted in which ADV velocity measurements were taken and have been used to validate a CFD model. Additionally, it was found that certain diffuser configurations showed pseudo - 2D behaviour such that the recorded data could be used to validate 2D simulations of the aeration tank. A CFD model using the Eulerian-Eulerian multiphase formulation in OpenFOAM was created to replicate the bubble driven fluid flow and free surface effects in the pilot-scale aeration tank. The influence of the inlet conditions, bubble diameter size and bubble dynamic models on the generated results were investigated and compared with the experimental data to validate the modelling choices. As a result, a 2D and 3D CFD model of the aeration tank was defined and validated against the experimental ADV data. Using the results, a procedure for coupling the biokinetics into the hydrodynamics was described in OpenFOAM. The difficulties that arose from transferring a two-phase solution with a free surface to a single-phase solver was outlined and solutions to the issues were defined and assessed. The mass transfer of oxygen into the fluid was modelled and compared with experimental results from the membrane diffuser manufactures to confirm the accuracy of the model. The oxygen mass transfer model was used to assess how the membrane diffuser setup and flow rate impacts the oxygenation of the reactor. It was found that increasing the number of aerating diffusers while keeping the total air flow rate the same significantly increased the oxygenation of the tank in comparison to just increasing the air flow rate which was found to only slightly increase the oxygenation. Additionally, a curve fitting procedure was described to derive a global oxygen transfer rate coefficient and saturation value from the CFD simulation for specific aeration tank setups and assessment of the values found they could give insight to the hydrodynamic behaviour in the reactor. The simulations were further extended to include the biokinetics to describe the biological interactions. A simple biokinetic aeration model was proposed to assess the impact of the hydrodynamics, inlet and outlet locations, and flow rate on the biological processes in tank. It was found that inadequate mixing in the 2D simulation resulted in twice the required amount of time to reach the maximum biomass concentrations compared with the equivalent perfectly mixed reactor. It was shown that the location of the inlet and outlet with the same hydrodynamic flow fields could influence the biological processes. It was found that there was no difference in the biological performance of the 3D reactor with an aerating flow rate of 0.3 and 0.6 L/s such that it would be inefficient to aerate the tank at 0.6 L/s. Finally, the full ASM1 was implemented into the coupled model and compared with the conventional ASM1 model to assess the performance of the aeration tank at producing and removing nitrates and ammonium. It was found that inadequate mixing resulted in reduced efficiency of the reactor at producing and removing nitrates and ammonium, respectively, which would further impact the performance of the sequential rectors

CFD Modeling of Complex Chemical Processes: Multiscale and Multiphysics Challenges

Computational fluid dynamics (CFD), which uses numerical analysis to predict and model complex flow behaviors and transport processes, has become a mainstream tool in engineering process research and development. Complex chemical processes often involve coupling between dynamics at vastly different length and time scales, as well as coupling of different physical models. The multiscale and multiphysics nature of those problems calls for delicate modeling approaches. This book showcases recent contributions in this field, from the development of modeling methodology to its application in supporting the design, development, and optimization of engineering processes

Improvements in modelling wastewater treatment plants for design, optimisation and education

Seit mehr als 3 Jahrzehnten stehen Belebtschlammmodelle als Werkzeuge für die ingenieurtechnische Planung und Optimierung von Kläranlagen zur Verfügung. Die Verbreitung und Anwendung speziell im deutschsprachigen Raum ist dabei geringer als in anderen Weltregionen. Dies ist im Zusammenhang mit dem detaillierten DWA-Regel-werk zu sehen, das auf Seite der Anwendenden kaum zusätzlichen Bedarf für weitere Werk¬zeuge für die Anlagenplanung und –optimierung erwachsen lässt. Dies gilt ebenso für die Über¬wachungs- und Genehmigungsseite. Die vorliegende Arbeit bietet für verschiedenste Aspekte im Bereich der Kläranlagen-modellierung Methoden und Werkzeuge, um durch effizientere Nutzung eine weitere Etablierung voranzutreiben und eine breite allgemein verbindliche Anwendung zu manifestieren. Dies betrifft konkret: Protokolldefinition für eine allgemeine Vorgehensweise (Kapitel 1.4 und 7.1) Skriptbasierte Unterstützung der Datenauswertung, Prüfung und Aufbereitung (Kapitel 6 und 7.4) Zulaufdatengenerierung für lückenbehaftete Betriebsdaten (Kapitel 3) Analyse des Verweilzeitverhaltens basierend auf Betriebsdaten (Kapitel 5) Modellkopplung für plant-wide modelling (Kapitel 4 und 7.3) Modellerweiterungen für Belebtschlammmodelle (Kapitel 7.2) Basis sind wie bei klassischen Bemessungs¬frage¬stellungen die vorhandenen Betriebs¬da-ten von Kläranlagen. Für die Nutzung sowohl zur statischen Bemessung als auch zur dyna¬mi¬schen Simulation sind diese nach geeigneter Zusammenstellung und Aufbereitung hin¬sicht¬lich ihrer Eignung und Qualität zu bewerten. Dieser eher handwerkliche Schritt wird durch skriptbasierte Module unterstützt, um der eigentlichen Planungsaufgabe mehr Zeit widmen zu können. Eine beispielhafte Vorgehensweise wird in dieser Arbeit in Kapitel 6 präsentiert. Dies stellt aus Effizienz- und Qualitätsgründen einen Fortschritt dar. Die Betriebsdaten von kommunalen Kläranlagen speziell unterhalb der Größenklasse 5 sind sehr lückenbehaftet. Daher sind geeignete Methoden erforderlich, um die Daten zu einem kontinuierlichen Zulaufdatensatz aufzubereiten. Eine mögliche Methode findet sich in Kapitel 3 dieser Arbeit. Auch dies unterstützt die Qualitätsverbesserung. Für die praxisnahe Modellanwendung stellen die bereits verfügbaren Belebt¬schlamm-modelle eine geeignete Basis dar. Allerdings wurden einige offene Fragestellungen identifiziert. Konzepte und Vorschläge für entsprechende Modellerweiterungen finden sich im Kapitel 7.1. Dies betrifft den Umgang mit inerten Stofffrachten, Dosierung externer Kohlenstoffquellen, Lösungen für hohe Anteile industrieller Abwässer sowie die P-Elimination. Auch eine methodische Vorgehensweise für den praktischen Einsatz wurde basierend auf allgemeingültigeren Simulations¬protokollen entwickelt, um die Bear¬bei¬tung strukturierter und damit sowohl nachvollzieh¬barer als auch effizienter zu gestalten (Kapitel 1.4 und 7.1). Das Verweilzeitverhalten hat erheblichen Einfluss auf erzielbare Umsatzraten sowie die erreich¬baren Ablaufkonzentrationen. Eine diesbezügliche Analyse ist allerdings noch kein Standard¬werkzeug bei der Betrachtung bestehender Kläranlagen. Im Einzelfall bestehen allerdings erhebliche Optimierungspotentiale bei strömungsungünstiger Gestaltung. Neben der Nutzung von computational fluid dynamics (CFD) als Analysewerkzeug kann auch die Auswertung von speziellen Tracerversuchen oder die Nutzung vorliegender Daten für die Analyse des Verweilzeitverhaltens genutzt werden. Im Kapitel 5 finden sich entsprechende Erläuterungen und methodische Beispiele. Die zunehmende Durchdringung ingenieurtechnischer Bereiche mit IT-basierten Werk-zeu¬gen führt auch zu Weiterentwicklungen bei der Arbeit mit Daten. Die Besonder-heiten im Bereich der Kläranlagenplanung und Optimierung werden in dieser Arbeit beleuchtet und mit dem vorgestellten methodischen Rahmen eine Möglichkeit der modularisierten Abarbeitung wiederkehrender Aufgaben in Kapitel 6 demonstriert. Die Einbettung möglicher weiterer Werkzeuge wie z.B. Simulationssoftware in open source basierte Skripte ermöglicht eine maximale Flexibilität bei gleichzeitig hoher Transparenz. Je nach Aufgabenstellung finden sich in dieser Arbeit Ergänzungen und Hilfestellungen in Form von Werkzeugen oder methodischen Empfehlungen, um den Bearbeitungsaufwand zu minimieren sowie die Bearbeitungsqualität zu erhöhen unter gleichzeitiger Verbesserung der Transparenz für alle am Planungs- bzw. Optimierungsprozess Beteiligten. Dadurch wird eine tatsächliche Anwendung in der täglichen Ingenieurpraxis erheblich vereinfacht. Durch Integration der präsentierten Entwicklungen in die siedlungs¬wasserwirtschaftliche Ausbildung ist außerdem eine zukünftige niedrig¬schwelligere und damit breitere Nutzung zu erwarten.:1 General introduction 1 1.1 Explanation of terms 1 1.2 Motivation 2 1.3 Background 4 1.3.1 Quality assurance in the performance of simulation studies 4 1.3.2 Special features of simulation studies for wastewater treatment plants in German-speaking countries 6 1.4 Aims, differentiation and objectives 7 1.5 Structure of the document 9 1.6 References 10 2 Growth of science in activated sludge modelling – a critical bibliometric review 13 2.1 Highlights 13 2.2 Abstract 13 2.3 Introduction 14 2.3.1 Motivation 14 2.3.2 Introduction into bibliometrics 15 2.3.3 Objective 15 2.4 Material and Methods 16 2.4.1 Database and tools 16 2.4.1.1 Selection of database 16 2.4.1.2 Development of the number of data sets in the Web of Science 19 2.4.2 Bibliometric analysis of the entire data set 20 2.4.3 Analysis of time-related developments 23 2.4.4 Keyword development within the examined topic area 24 2.5 Results and Discussion 25 2.5.1 Bibliometric analysis of the entire database 25 2.5.2 Journal-based measures 28 2.5.3 Source dynamics 30 2.5.4 Author impact measures 30 2.5.5 Document-based measures 35 2.5.6 Structural Analysis 36 2.5.7 Analysis of time-related developments 40 2.5.8 Keyword development within the scientific field under investigation 44 2.6 Critical comments on the methodology 47 2.7 Recommendations for conducting a bibliometric analysis 49 2.8 Conclusions 50 2.9 References 52 3 A black-box model for generation of site-specific WWTP influent quality data based on plant routine data 56 3.1 Introduction 56 3.2 Material and Methods 58 3.3 Results and discussion 62 3.3.1 Test of robustness 63 3.3.2 Universality of the approach 66 3.4 Conclusions and outlook 69 3.5 References 70 4 Organic matter parameters in WWTP – a critical review and recommendations for application in activated sludge modelling 74 4.1 Highlights 74 4.2 Abstract 74 4.3 Introduction 75 4.4 Theoretical Considerations 76 4.5 Review of literature data of WWTP sludge 80 4.5.1 Literature survey 80 4.5.2 Measures related to total and volatile organic matter 81 4.5.3 Sludge composition based on biochemical families 83 4.6 Results and Discussion 85 4.6.1 Solids 85 4.6.2 COD and COD/VSS ratio 87 4.6.3 Connection between LPC and COD/VSS ratio 90 4.7 Application to plant-wide-modelling 92 4.7.1 Solids in Activated Sludge Models 92 4.7.2 Organic and inorganic solids 94 4.7.3 COD influent characterisation 96 4.7.4 Adaptation of research results and discussion 97 4.8 Conclusions 101 4.9 Data availability statement 101 4.10 References 101 5 Temperature as an alternative tracer for the determination of the mixing characteristics in wastewater treatment plants 108 5.1 Abstract 108 5.2 Introduction 108 5.2.1 Historical background 109 5.2.2 Alternatives in evaluation of tracer tests 110 5.2.3 Objective of this paper 112 5.3 Material and Methods 112 5.3.1 Lab-scale system 112 5.3.2 Pilot-scale system 113 5.3.3 Procedure 114 5.3.3.1 Substitute hydraulic model 114 5.3.3.2 Energy balance 115 5.3.3.3 Parameter estimation 117 5.4 Results and Discussion 118 5.4.1 Lab-scale system 118 5.4.2 Pilot-scale system 121 5.4.3 Sensitivity tests for optimised substitute model parameters 124 5.4.3.1 Lab scale tests 124 5.4.3.2 Pilot scale tests 126 5.4.4 Influence of recirculation 126 5.4.5 Consideration of variable flow rates 127 5.4.6 Impact of the structured model approach on ASM parameters 127 5.5 Conclusions 131 5.6 References 133 6 One script to solve it all – an open-source-based framework for a digital workflow based on WWTP data 137 6.1 Abstract 137 6.2 Highlights 138 6.3 Introduction 138 6.4 Fundamentals and requirements 138 6.5 Material and Methods 142 6.5.1 Background to the case study 142 6.5.2 Development of the concept 144 6.5.3 Technical implementation 145 6.6 Results 148 6.6.1 Preparation and data import 148 6.6.2 Plausibility checks 149 6.6.3 Calculation of design parameters (A198) 150 6.6.4 Design of WWTP (A131) 151 6.6.5 Activated sludge modelling 152 6.7 Discussion 153 6.7.1 Practical advantages of the developed methodology 153 6.7.2 Lessons learned from development process and first use 153 6.8 Conclusions 157 6.9 References 158 7 Enhancements for a practical application 161 7.1 Evolution of unified protocol of GMP taskgroup 161 7.1.1 Overview 161 7.1.2 Understand the plant + plant layout selection 163 7.1.3 Collection of existing data 163 7.1.4 Iterative process cycle for data analysis and plant model setup / adjustment 164 7.2 Extensions to the activated sludge model (ASM_EDU) 166 7.2.1 Background 166 7.2.2 Separation of inert particulate COD by origin 168 7.2.3 Integration of external carbon sources 169 7.2.4 Consideration of the influence of industrial discharges 171 7.2.5 Consideration of different precipitants in chemical P elimination 174 7.3 Plant-wide modelling 176 7.4 Digital transformation for efficiency enhancement 178 7.5 References 182 8 Conclusions and Outlook 187 8.1 Developments in the field of WWTP modelling 187 8.2 Future significance in science and application practice 188 8.3 Further scientific research needs 189 8.4 Changing the way engineering works 191 8.5 References 193 9 Appendices 195 9.1 Supplementary material for Chapter 4 195 9.1.1 References for sludge data 195 9.1.2 Data survey from references 217 9.2 Supplementary material for Chapter 6 217For more than three decades, activated sludge models have been used as tools for the engineering planning and optimisation of wastewater treatment plants. However, their use is less widespread, particularly in German-speaking countries, due to the detailed rules and regulations of the DWA, which do not create a demand for additional tools for plant planning and optimisation. This also applies to the surveillance and authorisation side. The current work offers methods and tools for various aspects of wastewater treatment plant modeling in order to promote further adoption through more efficient use and to facilitate a broad, generally binding application. This includes: Definition of a protocol for the general approach (Chapter 1.4 and 7.1) Script-based support for data evaluation, testing, and processing (Chapters 6 and 7.4) Generation of inflow data for incomplete operational data (Chapter 3) Analysis of residence time behavior based on operational data (Chapter 5) Model interfacing for plant-wide modeling (Chapters 4 and 7.3) Model extensions for activated sludge models (Chapter 7.2) The existing operational data of wastewater treatment plants is the foundation for classical design questions. In order to be used in both static design and dynamic simulation, the data must be evaluated for their suitability and quality after appropriate compilation and processing. This manual step is supported by script-based modules to allow more time for the actual planning task. An exemplary procedure is presented in Chapter 6 of this thesis, which represents progress in terms of efficiency and quality. The operational data of municipal wastewater treatment plants, especially those below size class 5, are often incomplete. Therefore, it is necessary to develop suitable methods for processing these data into a continuous influent data set. One such method is presented in chapter 3 of this thesis. This method also helps to improve the quality of the data. For practical model application, the existing activated sludge models provide a suitable foundation. However, some open questions have been identified, and concepts and suggestions for corresponding model extensions can be found in chapter 7.1. These include handling inert material loads, dosing of external carbon sources, solutions for high proportions of industrial wastewater, and P elimination. A methodological approach for practical application has also been developed based on more general simulation protocols in order to structure the process and make it more comprehensible and efficient (Chapters 1.4 and 7.1). The residence time behaviour has a significant impact on the achievable conversion rates and effluent concentrations. However, an analysis of this behaviour is not yet a standard tool when considering existing wastewater treatment plants. In certain cases, however, there is significant potential for optimisation in cases of flow-unfavourable design. In addition to using computational fluid dynamics (CFD) as an analysis tool, the evaluation of special tracer tests or the use of existing data can also be used to analyse retention time behaviour. Chapter 1.4 und 7.1 provides explanations and examples The increasing use of IT-based tools in engineering fields also leads to further developments in working with data. The special features in the area of wastewater treatment plant planning and optimisation are highlighted in this thesis and a possibility of modularised processing of recurring tasks is demonstrated with the presented methodological framework in chapter 6. The embedding of possible further tools such as simulation software in open source-based scripts allows for maximum flexibility while maintaining a high degree of transparency. Depending on the task, this thesis provides supplements and assistance in the form of tools or methodological recommendations to minimise the processing effort and increase the processing quality while improving transparency for all those involved in the planning or optimisation process. This considerably simplifies actual application in daily engineering practice. By integrating the presented developments into urban water management training, a lower-threshold and thus broader use can also be expected in the future.:1 General introduction 1 1.1 Explanation of terms 1 1.2 Motivation 2 1.3 Background 4 1.3.1 Quality assurance in the performance of simulation studies 4 1.3.2 Special features of simulation studies for wastewater treatment plants in German-speaking countries 6 1.4 Aims, differentiation and objectives 7 1.5 Structure of the document 9 1.6 References 10 2 Growth of science in activated sludge modelling – a critical bibliometric review 13 2.1 Highlights 13 2.2 Abstract 13 2.3 Introduction 14 2.3.1 Motivation 14 2.3.2 Introduction into bibliometrics 15 2.3.3 Objective 15 2.4 Material and Methods 16 2.4.1 Database and tools 16 2.4.1.1 Selection of database 16 2.4.1.2 Development of the number of data sets in the Web of Science 19 2.4.2 Bibliometric analysis of the entire data set 20 2.4.3 Analysis of time-related developments 23 2.4.4 Keyword development within the examined topic area 24 2.5 Results and Discussion 25 2.5.1 Bibliometric analysis of the entire database 25 2.5.2 Journal-based measures 28 2.5.3 Source dynamics 30 2.5.4 Author impact measures 30 2.5.5 Document-based measures 35 2.5.6 Structural Analysis 36 2.5.7 Analysis of time-related developments 40 2.5.8 Keyword development within the scientific field under investigation 44 2.6 Critical comments on the methodology 47 2.7 Recommendations for conducting a bibliometric analysis 49 2.8 Conclusions 50 2.9 References 52 3 A black-box model for generation of site-specific WWTP influent quality data based on plant routine data 56 3.1 Introduction 56 3.2 Material and Methods 58 3.3 Results and discussion 62 3.3.1 Test of robustness 63 3.3.2 Universality of the approach 66 3.4 Conclusions and outlook 69 3.5 References 70 4 Organic matter parameters in WWTP – a critical review and recommendations for application in activated sludge modelling 74 4.1 Highlights 74 4.2 Abstract 74 4.3 Introduction 75 4.4 Theoretical Considerations 76 4.5 Review of literature data of WWTP sludge 80 4.5.1 Literature survey 80 4.5.2 Measures related to total and volatile organic matter 81 4.5.3 Sludge composition based on biochemical families 83 4.6 Results and Discussion 85 4.6.1 Solids 85 4.6.2 COD and COD/VSS ratio 87 4.6.3 Connection between LPC and COD/VSS ratio 90 4.7 Application to plant-wide-modelling 92 4.7.1 Solids in Activated Sludge Models 92 4.7.2 Organic and inorganic solids 94 4.7.3 COD influent characterisation 96 4.7.4 Adaptation of research results and discussion 97 4.8 Conclusions 101 4.9 Data availability statement 101 4.10 References 101 5 Temperature as an alternative tracer for the determination of the mixing characteristics in wastewater treatment plants 108 5.1 Abstract 108 5.2 Introduction 108 5.2.1 Historical background 109 5.2.2 Alternatives in evaluation of tracer tests 110 5.2.3 Objective of this paper 112 5.3 Material and Methods 112 5.3.1 Lab-scale system 112 5.3.2 Pilot-scale system 113 5.3.3 Procedure 114 5.3.3.1 Substitute hydraulic model 114 5.3.3.2 Energy balance 115 5.3.3.3 Parameter estimation 117 5.4 Results and Discussion 118 5.4.1 Lab-scale system 118 5.4.2 Pilot-scale system 121 5.4.3 Sensitivity tests for optimised substitute model parameters 124 5.4.3.1 Lab scale tests 124 5.4.3.2 Pilot scale tests 126 5.4.4 Influence of recirculation 126 5.4.5 Consideration of variable flow rates 127 5.4.6 Impact of the structured model approach on ASM parameters 127 5.5 Conclusions 131 5.6 References 133 6 One script to solve it all – an open-source-based framework for a digital workflow based on WWTP data 137 6.1 Abstract 137 6.2 Highlights 138 6.3 Introduction 138 6.4 Fundamentals and requirements 138 6.5 Material and Methods 142 6.5.1 Background to the case study 142 6.5.2 Development of the concept 144 6.5.3 Technical implementation 145 6.6 Results 148 6.6.1 Preparation and data import 148 6.6.2 Plausibility checks 149 6.6.3 Calculation of design parameters (A198) 150 6.6.4 Design of WWTP (A131) 151 6.6.5 Activated sludge modelling 152 6.7 Discussion 153 6.7.1 Practical advantages of the developed methodology 153 6.7.2 Lessons learned from development process and first use 153 6.8 Conclusions 157 6.9 References 158 7 Enhancements for a practical application 161 7.1 Evolution of unified protocol of GMP taskgroup 161 7.1.1 Overview 161 7.1.2 Understand the plant + plant layout selection 163 7.1.3 Collection of existing data 163 7.1.4 Iterative process cycle for data analysis and plant model setup / adjustment 164 7.2 Extensions to the activated sludge model (ASM_EDU) 166 7.2.1 Background 166 7.2.2 Separation of inert particulate COD by origin 168 7.2.3 Integration of external carbon sources 169 7.2.4 Consideration of the influence of industrial discharges 171 7.2.5 Consideration of different precipitants in chemical P elimination 174 7.3 Plant-wide modelling 176 7.4 Digital transformation for efficiency enhancement 178 7.5 References 182 8 Conclusions and Outlook 187 8.1 Developments in the field of WWTP modelling 187 8.2 Future significance in science and application practice 188 8.3 Further scientific research needs 189 8.4 Changing the way engineering works 191 8.5 References 193 9 Appendices 195 9.1 Supplementary material for Chapter 4 195 9.1.1 References for sludge data 195 9.1.2 Data survey from references 217 9.2 Supplementary material for Chapter 6 21

Investigating the relationship between shear and floe fate using CFD

The size, density and strength of floes play a major role in the removal of contaminants from water in physico-chemical treatment processes. The efficiency of the main removal processes is a function of floe size, strength and density. Changes in these parameters affect floe removal and hence the removal of adsorbed organic matter. Coagulation and flocculation efficiency and floe strength are often assessed using ajar tester. Here, computational fluid dynamics (CFD) was used to model the flow field within standard jar test apparatus and, using a Lagrangian particle trajectory model, to study the effects of turbulence on individual floes. The hydrodynamic environments were also investigated experimentally using laser Doppler anemometry (LDA) and particle image velocimetry (PIV) measurement techniques. Combining numerical and experimental data, velocity gradient values at which floe breakage occurs were postulated for three different floe suspensions. Although the threshold values are determined using jar test and CFD data in combination, they are based on the floes’ resistance to induced velocity gradients. This is a significant result, as previous breakage thresholds have been expressed only in terms of mixing speed and cannot be applied at full scale. With this in mind, work was subsequently undertaken to use CFD to model numerically the hydrodynamic conditions within two full scale flocculation vessels; one mechanically mixed, the other hydraulically mixed. This section of work had two principal aims; firstly, to investigate the perceived benefits of using CFD to model the hydraulic performance of the flocculation process at two large surface water treatment works, and secondly, to investigate the practicality and effectiveness of using CFD and jar test results in combination to consider floe fate in the flocculation vessels (in terms of growth, breakage and residence time). This work drew upon the results and conclusions of the previous laboratory scale work and facilitated a greater insight into flocculation processes. Improved understanding of flocculator hydrodynamics can only serve to improve design procedures and standards for future installations.Ph

Generation of (synthetic) influent data for performing wastewater treatment modelling studies

The success of many modelling studies strongly depends on the availability of sufficiently long influent time series - the main disturbance of a typical wastewater treatment plant (WWTP) - representing the inherent natural variability at the plant inlet as accurately as possible. This is an important point since most modelling projects suffer from a lack of realistic data representing the influent wastewater dynamics. The objective of this paper is to show the advantages of creating synthetic data when performing modelling studies for WWTPs. This study reviews the different principles that influent generators can be based on, in order to create realistic influent time series. In addition, the paper summarizes the variables that those models can describe: influent flow rate, temperature and traditional/emerging pollution compounds, weather conditions (dry/wet) as well as their temporal resolution (from minutes to years). The importance of calibration/validation is addressed and the authors critically analyse the pros and cons of manual versus automatic and frequentistic vs Bayesian methods. The presentation will focus on potential engineering applications of influent generators, illustrating the different model concepts with case studies. The authors have significant experience using these types of tools and have worked on interesting case studies that they will share with the audience. Discussion with experts at the WWTmod seminar shall facilitate identifying critical knowledge gaps in current WWTP influent disturbance models. Finally, the outcome of these discussions will be used to define specific tasks that should be tackled in the near future to achieve more general acceptance and use of WWTP influent generators

XXXV Congress of the International Association of Hydrogeologists, Groundwater and Ecosystems – Abstract Book

Resumos das comunicações do XXXV Congresso da Associação Internacional de Hidrogeólogos (IAH