Advanced

Analytical and numerical description of the settling process in the activated sludge operation

Diehl, Stefan LU ; Sparr, Gunnar LU and Olsson, Gustaf LU (1990) 5th IAWPRC Workshop In Instrumentation, control, and automation of water and wastewater treatment and transport systems : proceedings of the 5th IAWPRC Workshop held in Yokohama and Kyoto, Japan, 26 July-3 August 1990 p.471-478
Abstract
The secondary clarifier or settler is crucial for the whole activated sludge operation. Consequently, it is important to obtain a reliable analytical model as well as a useful numerical method, which can be used in the automatic control of the settling process. Discontinuities (shocks) appear physically, and an analytical description as well as a stable numerical algorithm must be able to handle these discontinuities. A model based on the Kynch theory of sedimentation is used, where the settling flux is a function only of the local concentration and is assumed to have one inflexion point. For such non-convex flux functions, the settling process is qualitatively the same, independent of further assumptions on the shapes of the settling... (More)
The secondary clarifier or settler is crucial for the whole activated sludge operation. Consequently, it is important to obtain a reliable analytical model as well as a useful numerical method, which can be used in the automatic control of the settling process. Discontinuities (shocks) appear physically, and an analytical description as well as a stable numerical algorithm must be able to handle these discontinuities. A model based on the Kynch theory of sedimentation is used, where the settling flux is a function only of the local concentration and is assumed to have one inflexion point. For such non-convex flux functions, the settling process is qualitatively the same, independent of further assumptions on the shapes of the settling functions. Using the theory of nonlinear conservation laws, the main results obtained are: how to calculate transient and asymptotic behavior; how to control the concentration profile of the settler, in particular the depth of the sludge blanket, for a given load; and, a numerical algorithm which automatically preserves shocks and gives the physically correct solution according to the analytical treatment. The algorithm can be applied on any flux function (with more than one inflexion point). (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
sedimentation, secondary clarifier, settling process, nonlinear conservation laws, shockwaves
in
Instrumentation, control, and automation of water and wastewater treatment and transport systems : proceedings of the 5th IAWPRC Workshop held in Yokohama and Kyoto, Japan, 26 July-3 August 1990
editor
Briggs, R.
pages
8 pages
publisher
Pergamon
conference name
5th IAWPRC Workshop
ISBN
0-08-040776-5
language
English
LU publication?
yes
id
86a8fc46-e33d-48ea-9993-500c8ac1afcf (old id 2363738)
date added to LUP
2012-04-22 16:27:52
date last changed
2016-04-16 09:43:16
@misc{86a8fc46-e33d-48ea-9993-500c8ac1afcf,
  abstract     = {The secondary clarifier or settler is crucial for the whole activated sludge operation. Consequently, it is important to obtain a reliable analytical model as well as a useful numerical method, which can be used in the automatic control of the settling process. Discontinuities (shocks) appear physically, and an analytical description as well as a stable numerical algorithm must be able to handle these discontinuities. A model based on the Kynch theory of sedimentation is used, where the settling flux is a function only of the local concentration and is assumed to have one inflexion point. For such non-convex flux functions, the settling process is qualitatively the same, independent of further assumptions on the shapes of the settling functions. Using the theory of nonlinear conservation laws, the main results obtained are: how to calculate transient and asymptotic behavior; how to control the concentration profile of the settler, in particular the depth of the sludge blanket, for a given load; and, a numerical algorithm which automatically preserves shocks and gives the physically correct solution according to the analytical treatment. The algorithm can be applied on any flux function (with more than one inflexion point).},
  author       = {Diehl, Stefan and Sparr, Gunnar and Olsson, Gustaf},
  editor       = {Briggs, R.},
  isbn         = {0-08-040776-5},
  keyword      = {sedimentation,secondary clarifier,settling process,nonlinear conservation laws,shockwaves},
  language     = {eng},
  pages        = {471--478},
  publisher    = {ARRAY(0xc3b67d8)},
  series       = {Instrumentation, control, and automation of water and wastewater treatment and transport systems : proceedings of the 5th IAWPRC Workshop held in Yokohama and Kyoto, Japan, 26 July-3 August 1990},
  title        = {Analytical and numerical description of the settling process in the activated sludge operation},
  year         = {1990},
}