Interaction between ballasting agent and flocs in ballasted flocculation for the removal of suspended solids in water

Nurul Syahidah Zafisah, Wei Lun Ang, Abdul Wahab Mohammad, Nidal Hilal, Daniel J. Johnson

Research output: Contribution to journalArticle


The interaction between ballasted agent and flocs formed from coagulation/flocculation process is not well understood. This study sought to understand the interaction between ballasted agent and flocs by investigating the impact of ballasted agent on the flocs formation and subsequently the removal of suspended solids in water. Ballasted flocculation was conducted using jar tests where the dosage of flocculant and sand was varied at 1–4 mg/L and 2–8 g/L, respectively. The turbidity removal peaked (90%) at 2 mg/L of flocculant and 1 g/L of sand. It was observed that excessive dosing of sand resulted in the formation of premature flocs that settled quickly before having the chance to remove more suspended solids via sweep coagulation. This revealed that the ballasted agent would affect the coagulation-flocculation process and subsequently the removal of suspended solids. This study indicates that future research on the impact of the ballasted agent on different coagulation-flocculation mechanism should be explored to ensure the suspended solids could be removed with short settling time and without compromising the quality of treated water.

Original languageEnglish (US)
Article number101028
JournalJournal of Water Process Engineering
StatePublished - Feb 2020



  • Ballasted flocculation
  • Coagulation
  • Flocculation
  • Natural organic matter
  • Water treatment

ASJC Scopus subject areas

  • Biotechnology
  • Safety, Risk, Reliability and Quality
  • Waste Management and Disposal
  • Process Chemistry and Technology

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