Plant wide control problems in the activated sludge process have been revisited. The ultimate cri... more Plant wide control problems in the activated sludge process have been revisited. The ultimate criteria for controlling a complete plant have been systematically addressed only infrequently. In principle, the effluent has to meet the standard at a minimal cost. Basically, the process is at the time driven by disturbances, mostly via the influent flow, but sometimes created within the plant. An essential task for any control system is to either minimise the consequences of the disturbances or to even eliminate them, before they hit the process. In this paper the main purpose is to systematically classify cause-effect relationships between available knowledge and open questions. This qualitative reasoning is meant to better define what can be achieved in the operation of a plant. The dynamic of an activated sludge system span over several orders of magnitude, from seconds to months. These different time scales allow many control actions to be decoupled. As a result, slowly varying variables can be controlled while assuming the fast dynamics to be instantaneous. Likewise fast varying variables may be manipulated while the slow modes are considered constant. (Less)
... Rosén, Christian (författare) Jacobsen, Bo N. (författare) Guildal, Thomas (författare) visa ... more ... Rosén, Christian (författare) Jacobsen, Bo N. (författare) Guildal, Thomas (författare) visa fler... Olsson, Gustaf (författare) Ingildsen, Pernille (författare) Munk-Nielsen, Thomas (författare) Nielsen,Marinus (författare) Davidsson, Åsa (författare) la Cour Jansen, Jes (författare) visa ...
During the last two decades, the interrelationship between water and energy has become recognized... more During the last two decades, the interrelationship between water and energy has become recognized. Likewise, the couplings to food and agriculture are getting increasingly obvious and alarming. In the last year, a record number of extreme weather events have been reported from most parts of the world. This is a visible demonstration how consequences of climate change must be understood and alleviated. The impacts of economics, lifestyle, and alarming inequalities are becoming increasingly recognisable. If the wealthy part of the world is not willing not make radical changes it does not matter what the less wealthy half of the global population will do to meet the climate and resource crisis. The purpose of the book is to demonstrate and describe how climate change, water, energy, food, and lifestyle are closely depending on each other. It is not sufficient to handle one discipline isolated from the others. This is the traditional “component view”. The book defines and describes a sy...
This study highlights the need to increase our understanding of the interplay between sensor drif... more This study highlights the need to increase our understanding of the interplay between sensor drift and the performance of the automatic control system. The impact from biased sensors on the automatic control systems is rarely considered when different control strategies are assessed in water resource recovery facilities. Still, the harsh measurement environment with negative effects on sensor data quality is widely acknowledged. Simulations were used to show how sensor bias in an ammonium cascade feedback controller impacts aeration energy efficiency and total nitrogen removal in an activated sludge process. Response surface methodology was used to reduce the required number of simulations, and to consider the combined effect of two simultaneously biased sensors. The effects from flow variations, and negatively biased ammonium (−1 mg/L) and suspended solids sensors (−500 mg/L) reduced the nitrification aeration energy efficiency by between 7 and 25%. Less impact was seen on total ni...
In this survey the state of the art of wastewater treatment system control is presented. Instrume... more In this survey the state of the art of wastewater treatment system control is presented. Instrumentation, dynamical models, and identification applications are reviewed. Current practice in control is described, and computerization of wastewater treatment plants is discussed. Biological treatment systems have been emphasized. The interactions between unit processes and between the sewage treatment plant and the sewer network are also considered.
A general framework for the formulation and analysis of an overall decision support index is disc... more A general framework for the formulation and analysis of an overall decision support index is discussed. It is indicated that such an index allow evaluation of the combined effects of both design and operation (i) during the planning phase of new WWTPs, as well as (ii) for the evaluation of new operational strategies versus traditional expansions of plants already in operation. Attention is drawn to the problems of incorporating such factors as plant flexibility and robustness against failures in the index. These factors become especially relevant when decisions are to be made that affect the life span of a WWTP. Spatial and temporal separation of the optimisation problem are proposed to make the approach operational. It is not the intention of the authors to provide an exhaustive list of objective criterion functions, but rather to give the reader some examples illustrating the approach. (Less)
A new control strategy is introduced for operating anaerobic digestion processes efficiently at h... more A new control strategy is introduced for operating anaerobic digestion processes efficiently at high load. The control system includes a cascade controller embedded into a rule-based supervisory system based on extremum-seeking control. The control system measures pH and biogas production rate and varies the organic load by manipulating the influent flow. Good control performances were achieved during the start-up and steady-state running operations and during rejection of disturbances. The control system can run the process under a high load condition and efficiently reject disturbances without explicit measurement of the influent characteristics.
Plant wide control problems in the activated sludge process have been revisited. The ultimate cri... more Plant wide control problems in the activated sludge process have been revisited. The ultimate criteria for controlling a complete plant have been systematically addressed only infrequently. In principle, the effluent has to meet the standard at a minimal cost. Basically, the process is at the time driven by disturbances, mostly via the influent flow, but sometimes created within the plant. An essential task for any control system is to either minimise the consequences of the disturbances or to even eliminate them, before they hit the process. In this paper the main purpose is to systematically classify cause-effect relationships between available knowledge and open questions. This qualitative reasoning is meant to better define what can be achieved in the operation of a plant. The dynamic of an activated sludge system span over several orders of magnitude, from seconds to months. These different time scales allow many control actions to be decoupled. As a result, slowly varying variables can be controlled while assuming the fast dynamics to be instantaneous. Likewise fast varying variables may be manipulated while the slow modes are considered constant. (Less)
... Rosén, Christian (författare) Jacobsen, Bo N. (författare) Guildal, Thomas (författare) visa ... more ... Rosén, Christian (författare) Jacobsen, Bo N. (författare) Guildal, Thomas (författare) visa fler... Olsson, Gustaf (författare) Ingildsen, Pernille (författare) Munk-Nielsen, Thomas (författare) Nielsen,Marinus (författare) Davidsson, Åsa (författare) la Cour Jansen, Jes (författare) visa ...
During the last two decades, the interrelationship between water and energy has become recognized... more During the last two decades, the interrelationship between water and energy has become recognized. Likewise, the couplings to food and agriculture are getting increasingly obvious and alarming. In the last year, a record number of extreme weather events have been reported from most parts of the world. This is a visible demonstration how consequences of climate change must be understood and alleviated. The impacts of economics, lifestyle, and alarming inequalities are becoming increasingly recognisable. If the wealthy part of the world is not willing not make radical changes it does not matter what the less wealthy half of the global population will do to meet the climate and resource crisis. The purpose of the book is to demonstrate and describe how climate change, water, energy, food, and lifestyle are closely depending on each other. It is not sufficient to handle one discipline isolated from the others. This is the traditional “component view”. The book defines and describes a sy...
This study highlights the need to increase our understanding of the interplay between sensor drif... more This study highlights the need to increase our understanding of the interplay between sensor drift and the performance of the automatic control system. The impact from biased sensors on the automatic control systems is rarely considered when different control strategies are assessed in water resource recovery facilities. Still, the harsh measurement environment with negative effects on sensor data quality is widely acknowledged. Simulations were used to show how sensor bias in an ammonium cascade feedback controller impacts aeration energy efficiency and total nitrogen removal in an activated sludge process. Response surface methodology was used to reduce the required number of simulations, and to consider the combined effect of two simultaneously biased sensors. The effects from flow variations, and negatively biased ammonium (−1 mg/L) and suspended solids sensors (−500 mg/L) reduced the nitrification aeration energy efficiency by between 7 and 25%. Less impact was seen on total ni...
In this survey the state of the art of wastewater treatment system control is presented. Instrume... more In this survey the state of the art of wastewater treatment system control is presented. Instrumentation, dynamical models, and identification applications are reviewed. Current practice in control is described, and computerization of wastewater treatment plants is discussed. Biological treatment systems have been emphasized. The interactions between unit processes and between the sewage treatment plant and the sewer network are also considered.
A general framework for the formulation and analysis of an overall decision support index is disc... more A general framework for the formulation and analysis of an overall decision support index is discussed. It is indicated that such an index allow evaluation of the combined effects of both design and operation (i) during the planning phase of new WWTPs, as well as (ii) for the evaluation of new operational strategies versus traditional expansions of plants already in operation. Attention is drawn to the problems of incorporating such factors as plant flexibility and robustness against failures in the index. These factors become especially relevant when decisions are to be made that affect the life span of a WWTP. Spatial and temporal separation of the optimisation problem are proposed to make the approach operational. It is not the intention of the authors to provide an exhaustive list of objective criterion functions, but rather to give the reader some examples illustrating the approach. (Less)
A new control strategy is introduced for operating anaerobic digestion processes efficiently at h... more A new control strategy is introduced for operating anaerobic digestion processes efficiently at high load. The control system includes a cascade controller embedded into a rule-based supervisory system based on extremum-seeking control. The control system measures pH and biogas production rate and varies the organic load by manipulating the influent flow. Good control performances were achieved during the start-up and steady-state running operations and during rejection of disturbances. The control system can run the process under a high load condition and efficiently reject disturbances without explicit measurement of the influent characteristics.
(Buchbeschreibung)
Das locker und verständlich verfasste Lehr- und Handbuch bietet einen vollst... more (Buchbeschreibung)
Das locker und verständlich verfasste Lehr- und Handbuch bietet einen vollständigen und systematischen Querschnitt durch die gesamte Prozessleittechnik. Alle Bereiche, die für die Prozessleittechnik und Automatisierungstechnik von Bedeutung sind, wie Beispielsweise Echtzeitprogrammierung, digitale Regelung, Messsignalverarbeitung und Datenkommunikation werden ausführlich behandelt. Zudem werden diese Ausführungen durch praxisrelevante Themen, wie die Anwendung von Bussystemen und die Gestaltung der Mensch-Maschine Schnittstelle ergänzt.
Unter anderem werden aktuelle Fragestellungen, wie Beispielsweise VMEbus, der MAP-Standard, Feldbusse und ISDN behandelt. Die internationale Erfahrung der Autoren in Industrie und Forschung spiegelt sich in der ausgewogenen und oftmals kritisch wertenden Betrachtungsweise wieder. Zahlreiche Hinweise auf aktuelle Normen und Standards erlauben den Praxisbezug dieses Lehrbuches. Jedes Kapitel wird durch ausführliche, kommentierte Literaturhinweise abgeschlossen.
Uploads
Das locker und verständlich verfasste Lehr- und Handbuch bietet einen vollständigen und systematischen Querschnitt durch die gesamte Prozessleittechnik. Alle Bereiche, die für die Prozessleittechnik und Automatisierungstechnik von Bedeutung sind, wie Beispielsweise Echtzeitprogrammierung, digitale Regelung, Messsignalverarbeitung und Datenkommunikation werden ausführlich behandelt. Zudem werden diese Ausführungen durch praxisrelevante Themen, wie die Anwendung von Bussystemen und die Gestaltung der Mensch-Maschine Schnittstelle ergänzt.
Unter anderem werden aktuelle Fragestellungen, wie Beispielsweise VMEbus, der MAP-Standard, Feldbusse und ISDN behandelt. Die internationale Erfahrung der Autoren in Industrie und Forschung spiegelt sich in der ausgewogenen und oftmals kritisch wertenden Betrachtungsweise wieder. Zahlreiche Hinweise auf aktuelle Normen und Standards erlauben den Praxisbezug dieses Lehrbuches. Jedes Kapitel wird durch ausführliche, kommentierte Literaturhinweise abgeschlossen.