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Systematic Approach to the Design of Operation and Control Policies in Activated Sludge Systems

de Araujo, Antonio C. B.; Gallani, Simone; Mulas, Michela and Olsson, Gustaf LU (2011) In Industrial & Engineering Chemistry Research 50(14). p.8542-8557
Abstract
This article describes the systematic design of a control structure for a biological wastewater treatment process as given by the test-bed Benchmark Simulation Model No. 1 (BSM1) and Activated Sludge Model No. 1 (ASM1). The objective of this work was to formalize and implement a systematic and yet simple procedure for the selection of control structures in wastewater treatment plants (WWTPs) and to show that the application of the proposed methodology agrees with the "empirical" findings regarding the operation of this process. The motivation underlying this endeavor was to search for a control configuration that leads to optimal economic operation while promptly rejecting disturbances at lower layers in the control hierarchy, thus... (More)
This article describes the systematic design of a control structure for a biological wastewater treatment process as given by the test-bed Benchmark Simulation Model No. 1 (BSM1) and Activated Sludge Model No. 1 (ASM1). The objective of this work was to formalize and implement a systematic and yet simple procedure for the selection of control structures in wastewater treatment plants (WWTPs) and to show that the application of the proposed methodology agrees with the "empirical" findings regarding the operation of this process. The motivation underlying this endeavor was to search for a control configuration that leads to optimal economic operation while promptly rejecting disturbances at lower layers in the control hierarchy, thus avoiding violation of the more important regulatory constraints on effluent discharge. We started by optimizing a steady-state nonlinear model of the process for various important disturbances. The results confirmed that it is economically optimal to control the oxygen concentration in the aerobic basins and the nitrate in the second anoxic tank at their respective lower bounds, whereas the effluent ammonia from the bioreactors should be controlled at its upper limit. In addition, because it is good practice to operate with minimal manipulation, the wastage flow rate should be fixed at its nominal optimal set point. The proposed decentralized control configuration, consisting of simple PI controllers, is capable of maintaining the process well within the regulatory limits at a small cost when dynamic disturbances represented by three weather files affect the process, therefore suggesting that, according to the applied systematic methodology, more complex (multivariable) regulators are not necessary for the ASM1 process. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Industrial & Engineering Chemistry Research
volume
50
issue
14
pages
8542 - 8557
publisher
The American Chemical Society
external identifiers
  • wos:000292850400018
  • scopus:79960381868
ISSN
0888-5885
DOI
10.1021/ie101703s
language
English
LU publication?
yes
id
f70de0d9-8afc-4171-83c3-332c1e7bb2ed (old id 2091592)
date added to LUP
2011-08-25 14:12:44
date last changed
2017-03-12 03:53:02
@article{f70de0d9-8afc-4171-83c3-332c1e7bb2ed,
  abstract     = {This article describes the systematic design of a control structure for a biological wastewater treatment process as given by the test-bed Benchmark Simulation Model No. 1 (BSM1) and Activated Sludge Model No. 1 (ASM1). The objective of this work was to formalize and implement a systematic and yet simple procedure for the selection of control structures in wastewater treatment plants (WWTPs) and to show that the application of the proposed methodology agrees with the "empirical" findings regarding the operation of this process. The motivation underlying this endeavor was to search for a control configuration that leads to optimal economic operation while promptly rejecting disturbances at lower layers in the control hierarchy, thus avoiding violation of the more important regulatory constraints on effluent discharge. We started by optimizing a steady-state nonlinear model of the process for various important disturbances. The results confirmed that it is economically optimal to control the oxygen concentration in the aerobic basins and the nitrate in the second anoxic tank at their respective lower bounds, whereas the effluent ammonia from the bioreactors should be controlled at its upper limit. In addition, because it is good practice to operate with minimal manipulation, the wastage flow rate should be fixed at its nominal optimal set point. The proposed decentralized control configuration, consisting of simple PI controllers, is capable of maintaining the process well within the regulatory limits at a small cost when dynamic disturbances represented by three weather files affect the process, therefore suggesting that, according to the applied systematic methodology, more complex (multivariable) regulators are not necessary for the ASM1 process.},
  author       = {de Araujo, Antonio C. B. and Gallani, Simone and Mulas, Michela and Olsson, Gustaf},
  issn         = {0888-5885},
  language     = {eng},
  number       = {14},
  pages        = {8542--8557},
  publisher    = {The American Chemical Society},
  series       = {Industrial & Engineering Chemistry Research},
  title        = {Systematic Approach to the Design of Operation and Control Policies in Activated Sludge Systems},
  url          = {http://dx.doi.org/10.1021/ie101703s},
  volume       = {50},
  year         = {2011},
}