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A consistent modelling methodology for secondary settling tanks: A reliable numerical method.

Bürger, Raimund; Diehl, Stefan LU ; Farås, Sebastian LU ; Nopens, Ingmar and Torfs, Elena (2013) In Water Science and Technology 68(1). p.192-208
Abstract
The consistent modelling methodology for secondary settling tanks (SSTs) leads to a partial differential equation (PDE) of nonlinear convection–diffusion type as a one-dimensional model for the solids concentration as a function of depth and time. This PDE includes a flux that depends discontinuously on spatial position modelling hindered settling and bulk flows, a singular source term describing the feed mechanism, a degenerating term accounting for sediment compressibility, and a dispersion term for turbulence. In addition, the solution itself is discontinuous. A consistent, reliable and robust numerical method that properly handles these difficulties is presented. Many constitutive relations for hindered settling, compression and... (More)
The consistent modelling methodology for secondary settling tanks (SSTs) leads to a partial differential equation (PDE) of nonlinear convection–diffusion type as a one-dimensional model for the solids concentration as a function of depth and time. This PDE includes a flux that depends discontinuously on spatial position modelling hindered settling and bulk flows, a singular source term describing the feed mechanism, a degenerating term accounting for sediment compressibility, and a dispersion term for turbulence. In addition, the solution itself is discontinuous. A consistent, reliable and robust numerical method that properly handles these difficulties is presented. Many constitutive relations for hindered settling, compression and dispersion can be used within the model, allowing the user to switch on and off effects of interest depending on the modelling goal as well as investigate the suitability of certain constitutive expressions. Simulations show the effect of the dispersion term on effluent suspended solids and total sludge mass in the SST. The focus is on correct implementation whereas calibration and validation are not pursued. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
continuous sedimentation, partial differential equation, secondary clarifier, simulation model, wastewater treatment
in
Water Science and Technology
volume
68
issue
1
pages
192 - 208
publisher
IWA Publishing
external identifiers
  • wos:000321336600023
  • scopus:84881140388
ISSN
0273-1223
DOI
10.2166/wst.2013.239
language
English
LU publication?
yes
id
c225b9ce-71f8-4290-8c9d-8999287b4009 (old id 3958770)
date added to LUP
2013-09-26 13:07:55
date last changed
2019-03-17 03:22:09
@article{c225b9ce-71f8-4290-8c9d-8999287b4009,
  abstract     = {The consistent modelling methodology for secondary settling tanks (SSTs) leads to a partial differential equation (PDE) of nonlinear convection–diffusion type as a one-dimensional model for the solids concentration as a function of depth and time. This PDE includes a flux that depends discontinuously on spatial position modelling hindered settling and bulk flows, a singular source term describing the feed mechanism, a degenerating term accounting for sediment compressibility, and a dispersion term for turbulence. In addition, the solution itself is discontinuous. A consistent, reliable and robust numerical method that properly handles these difficulties is presented. Many constitutive relations for hindered settling, compression and dispersion can be used within the model, allowing the user to switch on and off effects of interest depending on the modelling goal as well as investigate the suitability of certain constitutive expressions. Simulations show the effect of the dispersion term on effluent suspended solids and total sludge mass in the SST. The focus is on correct implementation whereas calibration and validation are not pursued.},
  author       = {Bürger, Raimund and Diehl, Stefan and Farås, Sebastian and Nopens, Ingmar and Torfs, Elena},
  issn         = {0273-1223},
  keyword      = {continuous sedimentation,partial differential equation,secondary clarifier,simulation model,wastewater treatment},
  language     = {eng},
  number       = {1},
  pages        = {192--208},
  publisher    = {IWA Publishing},
  series       = {Water Science and Technology},
  title        = {A consistent modelling methodology for secondary settling tanks: A reliable numerical method.},
  url          = {http://dx.doi.org/10.2166/wst.2013.239},
  volume       = {68},
  year         = {2013},
}