Journal of Engineering Mathematics

, Volume 60, Issue 3–4, pp 265–291 | Cite as

A regulator for continuous sedimentation in ideal clarifier–thickener units

  • Stefan Diehl


The purpose of this paper is to present a regulator for control of the continuous-sedimentation process in a clarifier–thickener unit when this is modelled in one space dimension and when the settling properties of the solids obey Kynch’s assumption. The model is a scalar hyperbolic conservation law with space-discontinuous flux function and point source. The most desired type of solution contains a large discontinuity. A common objective is to control the movement of this discontinuity subject to the requirement that the effluent of the process have zero concentration of particles. In addition, there may be a requirement that the underflow concentration of the thickened suspension lie above a predefined value. Based on previous results on the nonlinear behaviour of the process, a nonlinear regulator is presented. It controls the location of the large discontinuity indirectly by controlling the total mass. The process is stabilized significantly and large input oscillations can be handled.


Clarifier–thickener Continuous sedimentation Control Dynamic behaviour Nonlinear regulator 


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Copyright information

© Springer Science + Business Media B.V. 2007

Authors and Affiliations

  1. 1.Centre for Mathematical SciencesLund UniversityLundSweden

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