Drinking water pellet softening: prediction the terminal settling velocity of natural particles

Onno Kramer, Peter de Moel, E.T. Baars, W.H. van Vugt, Jan Peter van der Hoek

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientific

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Natural particles are frequently applied in drinking water treatment in up-flow fluidisation processes. Additionally, sedimentation processes are applied to clarify water and to concentrate solids. To estimate the terminal settling velocity of single solid particles in a liquid system, a comprehensive collection of equations is available. For perfectly round spheres, settling velocity can be calculated accurately. For naturally imperfect particles, however, experimentally measured settling velocity shows considerable deviation compared to calculated values. This article discusses a number of experiments demonstrating this deviation and the applicability of commonly used drag-coefficient equation by Brown-Lawler.
Original languageEnglish
Title of host publication5th IWA Young Water Professionals BeNeLux conference
Subtitle of host publicationGhent, Belgium
Number of pages3
Publication statusPublished - 2017
Event5th IWA Young Water Professionals BeNeLux conference - Ghent, Belgium
Duration: 5 Jul 20177 Jul 2017
Conference number: 5


Conference5th IWA Young Water Professionals BeNeLux conference
Internet address


  • drinking water
  • terminal settling velocity
  • calcium carbonate pellets
  • pellet softening
  • garnet sand
  • grained calcite seeding material
  • drag coefficient

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