Estimating the hindered-settling flux function from a batch test in a cone

Research output: Contribution to journalArticle

Abstract

The hindered-settling velocity function for the modelling, simulation and control of secondary settling tanks can be determined from batch tests. The conventional method is to measure the velocity of the descending sludge-supernatant interface (sludge blanket) as the change in height over time in a vessel with constant cross-sectional area. Each such experiment provides one point on the flux curve since, under idealizing assumptions (monodisperse suspension, no wall-effects), the concentration of sludge remains constant just below the sludge blanket until some wave from the bottom reaches it. A newly developed method of estimation, based on the theory of nonlinear hyperbolic partial differential equations, is applied to both synthetic and experimental data. The method demonstrates that a substantial portion of the flux function may be estimated from a single batch test in a conical vessel. The new method takes into consideration that during an ideal settling experiment in a cone, the concentration just below the sludge blanket increases with time since the mass of suspended solids occupy a reduced volume over time.

Details

Authors
Organisations
External organisations
  • University of Concepción
  • University of Pretoria
  • Mälardalen University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Engineering
  • Mathematics

Keywords

  • Identification, Inverse problem, Partial differential equation, Sedimentation
Original languageEnglish
Pages (from-to)244-253
Number of pages10
JournalChemical Engineering Science
Volume192
Early online date2018 Jul 17
Publication statusPublished - 2018 Dec 31
Publication categoryResearch
Peer-reviewedYes