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On constitutive functions for hindered settling velocity in 1-D settler models : Selection of appropriate model structure

Torfs, Elena; Balemans, Sophie; Locatelli, Florent; Diehl, Stefan LU ; Bürger, Raimund; Laurent, Julien; François, Pierre and Nopens, Ingmar (2017) In Water Research 110. p.38-47
Abstract

Advanced 1-D models for Secondary Settling Tanks (SSTs) explicitly account for several phenomena that influence the settling process (such as hindered settling and compression settling). For each of these phenomena a valid mathematical expression needs to be selected and its parameters calibrated to obtain a model that can be used for operation and control. This is, however, a challenging task as these phenomena may occur simultaneously. Therefore, the presented work evaluates several available expressions for hindered settling based on long-term batch settling data. Specific attention is paid to the behaviour of these hindered settling functions in the compression region in order to evaluate how the modelling of sludge compression is... (More)

Advanced 1-D models for Secondary Settling Tanks (SSTs) explicitly account for several phenomena that influence the settling process (such as hindered settling and compression settling). For each of these phenomena a valid mathematical expression needs to be selected and its parameters calibrated to obtain a model that can be used for operation and control. This is, however, a challenging task as these phenomena may occur simultaneously. Therefore, the presented work evaluates several available expressions for hindered settling based on long-term batch settling data. Specific attention is paid to the behaviour of these hindered settling functions in the compression region in order to evaluate how the modelling of sludge compression is influenced by the choice of a certain hindered settling function. The analysis shows that the exponential hindered settling forms, which are most commonly used in traditional SST models, not only account for hindered settling but partly lump other phenomena (compression) as well. This makes them unsuitable for advanced 1-D models that explicitly include each phenomenon in a modular way. A power-law function is shown to be more appropriate to describe the hindered settling velocity in advanced 1-D SST models.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
1-D modelling, Batch settling test, Calibration, Compression settling, Secondary clarifier
in
Water Research
volume
110
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85004065487
  • wos:000394200800004
ISSN
0043-1354
DOI
10.1016/j.watres.2016.11.067
language
English
LU publication?
yes
id
66244af1-ebe0-495d-bbcc-741552956d26
date added to LUP
2017-02-03 08:56:59
date last changed
2018-01-07 11:47:54
@article{66244af1-ebe0-495d-bbcc-741552956d26,
  abstract     = {<p>Advanced 1-D models for Secondary Settling Tanks (SSTs) explicitly account for several phenomena that influence the settling process (such as hindered settling and compression settling). For each of these phenomena a valid mathematical expression needs to be selected and its parameters calibrated to obtain a model that can be used for operation and control. This is, however, a challenging task as these phenomena may occur simultaneously. Therefore, the presented work evaluates several available expressions for hindered settling based on long-term batch settling data. Specific attention is paid to the behaviour of these hindered settling functions in the compression region in order to evaluate how the modelling of sludge compression is influenced by the choice of a certain hindered settling function. The analysis shows that the exponential hindered settling forms, which are most commonly used in traditional SST models, not only account for hindered settling but partly lump other phenomena (compression) as well. This makes them unsuitable for advanced 1-D models that explicitly include each phenomenon in a modular way. A power-law function is shown to be more appropriate to describe the hindered settling velocity in advanced 1-D SST models.</p>},
  author       = {Torfs, Elena and Balemans, Sophie and Locatelli, Florent and Diehl, Stefan and Bürger, Raimund and Laurent, Julien and François, Pierre and Nopens, Ingmar},
  issn         = {0043-1354},
  keyword      = {1-D modelling,Batch settling test,Calibration,Compression settling,Secondary clarifier},
  language     = {eng},
  month        = {03},
  pages        = {38--47},
  publisher    = {Elsevier},
  series       = {Water Research},
  title        = {On constitutive functions for hindered settling velocity in 1-D settler models : Selection of appropriate model structure},
  url          = {http://dx.doi.org/10.1016/j.watres.2016.11.067},
  volume       = {110},
  year         = {2017},
}