Effects of acidification on dewaterability and Aluminum concentration of alum sludge

Shanghao Huang, Jiann Long Chen, Kung Yuh Chiang, Chih Chao Wu

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22 Scopus citations


This study utilizes the Terzaghi-Voigt model to characterize the effects of acidification on the dewaterability of alum sludge. Alum sludge, which was obtained from the sedimentation basins of a water treatment plant using poly aluminum chloride as coagulant, was acidified to different pH levels with sulfuric acid. The dewaterability of the acidified sludge was characterized by expression tests. The results show dewaterability enhancement was insignificant until pH was below 4. Further improvement in dewaterability can be achieved by polymer conditioning. The Terzaghi-Voigt model can be applied to explain the difference in dewaterability between acidified and original sludges. Results also show dissolved aluminum concentrations were controlled by minerals in the influent rather than amorphous aluminum hydroxide.

Original languageEnglish
Pages (from-to)1165-1169
Number of pages5
JournalSeparation Science and Technology
Issue number8
StatePublished - Jan 2010


  • Acidification
  • Alum sludge
  • Creeping factor
  • Dewaterability
  • Expression
  • Secondary consolidation


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