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Towards improved 1-D settler modelling: calibration of the Bürger model and case study

Torfs, Elena; Vlasschaert, Pieter; Amerlink, Youri; Bürger, Raimund; Diehl, Stefan LU ; Farås, Sebastian LU and Nopens, Ingmar (2013) 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013) In Proceedings of 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013)
Abstract
Recently, Burger et al. (2011) developed a new 1-D SST model which allows for more realistic

predictions of the sludge settling behaviour than traditional 1-D models used to date. However, the

addition of a compression function in this new 1-D model complicates the model calibration. This

study aims to report advances in the calibration of this novel 1-D model. Data of the evolution of

the sludge blanket height during batch settling experiments were collected at different initial solids

concentrations. Based on the linear slopes of the batch settling curves the hindered settling velocity

functions by Vesilind (1968) and Takacs et al. (1991) were calibrated. Although both... (More)
Recently, Burger et al. (2011) developed a new 1-D SST model which allows for more realistic

predictions of the sludge settling behaviour than traditional 1-D models used to date. However, the

addition of a compression function in this new 1-D model complicates the model calibration. This

study aims to report advances in the calibration of this novel 1-D model. Data of the evolution of

the sludge blanket height during batch settling experiments were collected at different initial solids

concentrations. Based on the linear slopes of the batch settling curves the hindered settling velocity

functions by Vesilind (1968) and Takacs et al. (1991) were calibrated. Although both settling

velocity functions gave a good fit to the experimental data, very large confidence intervals were

found for the parameters of the settling velocity by Takacs. Global sensitivity analysis showed that

it is not possible to find a unique set of parameter values for the settling function by Takacs based on

experimental data of the hindered settling velocity. Subsequently, the calibrated Vesilind settling

velocity was implemented in the 1-D model by Burger et al. (2011) and the parameters of the

additional compression function were calibrated by fitting the model by Burger et al. (2011) to the

batch settling curves. Simulation results showed that while the 1-D model by Takacs et al. (1991)

underpredicted the experimental data of sludge blanket heights, the model by Burger et al. (2011)

was able to predict the experimental data far more accurately. However, a global sensitivity analysis

showed that no unique optimum for the combined set of hindered and compression parameters

could be found. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
SST, calibration, global sensitivity analysis, compression settling, batch settling tests
in
Proceedings of 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013)
pages
17 pages
conference name
86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013)
language
English
LU publication?
yes
id
1322247a-d0bf-4e05-a3e2-b920a9444335 (old id 4174878)
alternative location
http://weftec2013.conferencespot.org/55109-wef-1.218281/t-010-1.220954/408-1.220990/a-294-1.220997
date added to LUP
2014-01-20 17:58:23
date last changed
2017-02-13 13:14:11
@inproceedings{1322247a-d0bf-4e05-a3e2-b920a9444335,
  abstract     = {Recently, Burger et al. (2011) developed a new 1-D SST model which allows for more realistic<br/><br>
predictions of the sludge settling behaviour than traditional 1-D models used to date. However, the<br/><br>
addition of a compression function in this new 1-D model complicates the model calibration. This<br/><br>
study aims to report advances in the calibration of this novel 1-D model. Data of the evolution of<br/><br>
the sludge blanket height during batch settling experiments were collected at different initial solids<br/><br>
concentrations. Based on the linear slopes of the batch settling curves the hindered settling velocity<br/><br>
functions by Vesilind (1968) and Takacs et al. (1991) were calibrated. Although both settling<br/><br>
velocity functions gave a good fit to the experimental data, very large confidence intervals were<br/><br>
found for the parameters of the settling velocity by Takacs. Global sensitivity analysis showed that<br/><br>
it is not possible to find a unique set of parameter values for the settling function by Takacs based on<br/><br>
experimental data of the hindered settling velocity. Subsequently, the calibrated Vesilind settling<br/><br>
velocity was implemented in the 1-D model by Burger et al. (2011) and the parameters of the<br/><br>
additional compression function were calibrated by fitting the model by Burger et al. (2011) to the<br/><br>
batch settling curves. Simulation results showed that while the 1-D model by Takacs et al. (1991)<br/><br>
underpredicted the experimental data of sludge blanket heights, the model by Burger et al. (2011)<br/><br>
was able to predict the experimental data far more accurately. However, a global sensitivity analysis<br/><br>
showed that no unique optimum for the combined set of hindered and compression parameters<br/><br>
could be found.},
  author       = {Torfs, Elena and Vlasschaert, Pieter and Amerlink, Youri and Bürger, Raimund and Diehl, Stefan and Farås, Sebastian and Nopens, Ingmar},
  booktitle    = {Proceedings of 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013)},
  keyword      = {SST,calibration,global sensitivity analysis,compression settling,batch settling tests},
  language     = {eng},
  pages        = {17},
  title        = {Towards improved 1-D settler modelling: calibration of the Bürger model and case study},
  year         = {2013},
}