Rule based control of a periodic activated sludge process

1998 ◽  
Vol 38 (3) ◽  
pp. 281-289 ◽  
Author(s):  
S. Isaacs ◽  
D. Thornberg
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Control Strategy ◽  
Periodic Operation ◽  
Rule Based ◽  
Criterion Functions ◽  
Strategy Performance ◽  
Working Region ◽  
And Control ◽  
Selection Of

A rule based control strategy for automatically adjusting phase lengths and aeration intensity for an activated sludge nutrient removal process based on a periodic operation is examined using simulations based on the Activated Sludge Model No. 1. The strategy is based on four criterion functions, two which determine the switching of the roles of two nitrifying/denitrifying reactors and two which adjust the dissolved oxygen setpoint levels in the two reactors as functions of ammonia and nitrate concentrations. Trajectory plots of reactor concentrations in the ammonia-nitrate plane are shown to be a useful means of visualizing process and control performance. Together, the trajectories from a working region in the ammonia-nitrate plane, the size and location of which can to some extent be predetermined by selection of the criterion functions. The presented results include the influence of one of the criterion functions on control strategy performance, how an incompatibility between two criterion functions can lead to unsymmetric reactor loading, and the effect of allowing simultaneous nitrification and denitrification during nitrifying periods by reducing the dissolved oxygen level as ammonia is consumed.

Control Strategy of Soluble Boron-Free Operation for a Small PWR

2017 ◽  
Author(s):  
Guangwen Bi ◽  
Chuntao Tang ◽  
Bo Yang
Keyword(s):  
Control Strategy ◽  
Power Distribution ◽  
Short Term ◽  
Control Rod ◽  
Burnable Poison ◽  
Power Operation ◽  
And Control ◽  
Power Distribution Control ◽  
Selection Of

Elimination of soluble boron will be a challenge to reactor operation for PWR. This paper is to promote a control strategy of soluble boron-free operation for a small PWR, through selection of burnable poison (BP), BP loading and control rod loading, based on the reactivity balance and manage requirement. The analysis for on-power operation and shutdown condition indicated that this strategy could be suitable for long-term and short-term reactivity and power distribution control for soluble boron-free operation.

Design of a generalized predictive controller for a biological wastewater treatment plant

2016 ◽  
Vol 73 (8) ◽  
pp. 1986-2006 ◽  
Author(s):  
M. Sadeghassadi ◽  
C. J. B. Macnab ◽  
D. Westwick
Keyword(s):  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Control Strategy ◽  
Treatment Plant ◽  
Effective Control ◽  
Activated Sludge Process ◽  
Measured Variable ◽  
Penalty Term ◽  
Predictive Controller

This paper presents a generalized predictive control (GPC) technique to regulate the activated sludge process found in a bioreactor used in wastewater treatment. The control strategy can track dissolved oxygen setpoint changes quickly, adapting to the system uncertainties and disturbances. Tests occur on an Activated Sludge Model No. 1 benchmark of an activated sludge process. A T filter added to the GPC framework results in an effective control strategy in the presence of coloured measurement noise. This work also suggests how a constraint on the measured variable can be added as a penalty term to the GPC framework which leads to improved control of the dissolved oxygen concentration in the presence of dynamic input disturbance.

A comparison between model and rule based control of a periodic activated sludge process

1998 ◽  
Vol 37 (12) ◽  
pp. 343-351 ◽  
Author(s):  
S. Isaacs ◽  
D. Thornberg
Keyword(s):  
Activated Sludge ◽  
Inorganic Nitrogen ◽  
Test Scenario ◽  
Rule Based ◽  
Criterion Functions ◽  
Model Predictions ◽  
Simple Rules ◽  
Fixed Phase ◽  
Total Inorganic Nitrogen ◽  
Better Than

Two strategies for control of nitrogen removal in an alternating activated sludge plant are compared. One is based on simple model predictions determining the cycle length at the beginning of each cycle. The other is based on simple rules relating present ammonia and nitrate concentrations. Both strategies are close in efficiency measured as effluent total (inorganic) nitrogen and both perform better than using fixed phase lengths for a test scenario describing a typical dry weather diurnal variation. After modifying the criterion functions of the rule based strategy the two strategies are found to produce equivalent controls, which means that the optimal criteria of the model based strategy can be fulfilled without the need for model predictions.

scholarly journals Design of fuel system to meet China 6 emissions requirements in hybrid electric vehicle

2021 ◽  
Vol 268 ◽  
pp. 01024
Author(s):  
Shenghua Qu ◽  
Yanlin Chen
Keyword(s):  
Control Strategy ◽  
Hybrid Electric Vehicle ◽  
Route Selection ◽  
Fuel System ◽  
Emission Regulations ◽  
Development Experience ◽  
Definition Of ◽  
Tank Pressure ◽  
And Control ◽  
Selection Of

Based on the interpretation of GB 18352.6-2016 and combined with the author's actual development experience, the key design points and solutions of the three key problems of fuel system that meet China 6 emission regulations are described, Technical route selection of evaporative emission, definition of technical route of fuel tank and control strategy of tank pressure, evaporative emission control, etc..

Freezing Degrees of Freedom During Motor Learning: A Systematic Review

Motor Control ◽  
2020 ◽  
Vol 24 (3) ◽  
pp. 457-471 ◽  
Author(s):  
Anderson Nascimento Guimarães ◽  
Herbert Ugrinowitsch ◽  
Juliana Bayeux Dascal ◽  
Alessandra Beggiato Porto ◽  
Victor Hugo Alves Okazaki
Keyword(s):  
Motor Learning ◽  
Control Strategy ◽  
Degrees Of Freedom ◽  
Control Strategies ◽  
System Solution ◽  
Dart Throwing ◽  
The Central Nervous System ◽  
Enormous Variation ◽  
And Control ◽  
Selection Of

According to Bernstein, the central nervous system solution to the human body’s enormous variation in movement choice and control when directing movement—the problem of degrees of freedom (DF)—is to freeze the number of possibilities at the beginning of motor learning. However, different strategies of freezing DF are observed in literature, and the means of selection of the control strategy during learning is not totally clear. This review investigated the possible effects of the class and objectives of the skill practiced on DF control strategies. The results of this review suggest that freezing or releasing the DF at the beginning of learning does not depend on the class (e.g., discrete skill class: football kick, dart throwing; continuous skill class: athletic march, handwriting) or objective of the skill (e.g., balance, velocity, and accuracy), in isolation. However, an interaction between these two skill elements seems to exist and influences the selection of the DF control strategy.

scholarly journals Auto-Control Technique Using Gradient Method Based on Radial Basis Function Neural Networks to Control of an Activated Sludge Process of Wastewater Treatment

2020 ◽  
Vol 53 (5) ◽  
pp. 671-679
Author(s):  
Abdallah Lemita ◽  
Sebti Boulahbel ◽  
Sami Kahla ◽  
Moussa Sedraoui
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Control Strategy ◽  
Rbf Neural Network ◽  
Activated Sludge Process ◽  
Treatment Processes ◽  
Do Concentration

Dissolved oxygen (DO) concentration is a key variable in the activated sludge wastewater treatment processes. In this paper, an auto control strategy based on Euler method and gradient method with radial basis function (RBF) neural networks (NNs) is proposed to solve the DO concentration control problem in an activated sludge process of wastewater treatment. The control purpose is to maintain the dissolved oxygen concentration in the aerated tank for having the substrate concentration within the standard limits established by legislation of wastewater treatment. For that reason, a new proposed control strategy based on gradient descent method and RBF neural network has been used. Compared with RBF neural network PI control, the obtained results show the effectiveness in terms of both transient and steady performances of proposed control method for dissolved oxygen control in the activated sludge wastewater treatment processes.

Cycle Modeling and Optimization of an Integrally Geared sCO2 Compander

2017 ◽  
Author(s):  
Jeffrey Bennett ◽  
Jason Wilkes ◽  
Timothy Allison ◽  
Robert Pelton ◽  
Karl Wygant
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Inlet Temperature ◽  
Modeling And Optimization ◽  
Compressor Inlet ◽  
Two Stages ◽  
And Control ◽  
Selection Of

This paper presents the selection of a system configuration and off-design control method for an integrally geared compander based on cycle modeling and optimization. The goal of the cycle modeling was to determine a cycle configuration that would reach an efficiency of 50% at design conditions and to optimize off-design control to maintain high efficiencies. The compander is being developed for use in a concentrated solar power supercritical carbon dioxide power plant with expected turbine inlet temperatures of 705°C and utilizing dry cooling leading to compressor inlet temperature varying between 35°C and 55°C. The compander is unique as it consists of eight turbomachinery stages on four pinions all being driven by a single bull gear. The separate stages offer the opportunity to consider a variety of flow splits and cycle configurations including intercooling and multiple stages of reheat. Cycle modeling was conducted in two stages: on-design and off-design. On-design modeling was simulated with all components operating at their design point. This was used to compare the performance of different cycle configurations and design temperatures. Off-design modeling was then performed to investigate the temperature dependence of the cycle efficiency and power output and to develop a control strategy. Strategies considered and discussed include: turbine bypass, compressor recycle, inlet guide vanes, and inventory control. To determine the best operating conditions for each configuration and control strategy, a genetic algorithm was implemented to optimize the cycle performance across the range of operating temperatures being considered. The final selection of cycle configuration, design temperature and control strategy is also presented.

Modification of Small Activated Sludge Plants to Recycled Systems for Nitrogen Removal and Control of Settling Properties

1990 ◽  
Vol 22 (3-4) ◽  
pp. 117-122
Author(s):  
Asher Brenner
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Volume Fraction ◽  
Critical Parameters ◽  
Modification Process ◽  
Mode Of Operation ◽  
System Part ◽  
Recycle Rate ◽  
And Control ◽  
Selection Of

Modification of small activated sludge plants to recycled systems is proposed as a means to improve nitrogen removal and control of settling properties. The modification process involves separation of the aeration basin to anoxic and aerobic zones and addition of internal recycle of mixed liquor from the aerobic to the anoxic zone. This mode of operation may prevent problems of floating sludge in the final clarifier caused by uncontrolled denitrification. In the recycled system, part of the organic carbon is removed under anoxic conditions. Therefore, it may assist in the selection of microbial population with better settling characteristics, since most filamentous microbes have been reported to lack denitrifying ability. The modification considerations and guidelines are discussed based on experimental results obtained from operation of bench-scale recycled units. Influent COD/ammonia ratio, aerobic volume fraction, and recycle rate are shown to be critical parameters in the modification and operation of such systems.

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