Adaptive on-line steady-state optimization of slow dynamic processes

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

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Selection of one-dimensional sedimentation: models for on-line use

Water Science & Technology ◽

10.2166/wst.1995.0100 ◽

1995 ◽

Vol 31 (2) ◽

pp. 193-204 ◽

Cited By ~ 7

Author(s):

Koen Grijspeerdt ◽

Peter Vanrolleghem ◽

Willy Verstraete

Keyword(s):

Steady State ◽

Selection Criteria ◽

Data Sets ◽

Concentration Profiles ◽

A Posteriori ◽

One Dimensional ◽

On Line ◽

Dynamic Concentration ◽

Selection Of ◽

Modelling Task

A comparative study of several recently proposed one-dimensional sedimentation models has been made. This has been achieved by fitting these models to steady-state and dynamic concentration profiles obtained in a down-scaled secondary decanter. The models were evaluated with several a posteriori model selection criteria. Since the purpose of the modelling task is to do on-line simulations, the calculation time was used as one of the selection criteria. Finally, the practical identifiability of the models for the available data sets was also investigated. It could be concluded that the model of Takács et al. (1991) gave the most reliable results.

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Extending on-line dilution steady-state concentration range by modification of the merging stream and tandem injection continuous-flow methods

The Analyst ◽

10.1039/an9911600489 ◽

1991 ◽

Vol 116 (5) ◽

pp. 489 ◽

Cited By ~ 6

Author(s):

Yecheskel Israel ◽

Ramon M. Barnes

Keyword(s):

Steady State ◽

Continuous Flow ◽

Steady State Concentration ◽

On Line ◽

State Concentration

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Modification of Neuron PID Control in Case of Improper Learning Factors

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.433-440.6795 ◽

2012 ◽

Vol 433-440 ◽

pp. 6795-6801

Author(s):

Xue Gui Zhu ◽

Zhi Hong Fu ◽

Xing Zhe Hou

Keyword(s):

Steady State ◽

Reference Signal ◽

Stability And Convergence ◽

Simulation Experiments ◽

Slow Dynamic ◽

Penalty Factor ◽

The Stability ◽

Learning Factors ◽

Control Output ◽

Reference Input

Some modifications of conventional neuron proportional-integral-differential controller (NPID) are presented in this paper to prevent its slow dynamic response and loss of control in case of improper learning factors. The quasi-step signal replaces the step signal as the reference signal to improve the dynamic characteristics. The control output of NPID is modified every step by multiplying a penalty factor called senior teacher signal to suppress further the overshoot and compress the settling time. The steady-state error from the modified NPID (MNPID) is reduced or removed by adjusting dynamically reference input signal while excluding the pseudo steady state. Lots of simulation experiments are done to prove the stability and convergence of the MNPID control algorithm.

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