Influence of growth phase on harvesting of Chlorella zofingiensis by dissolved air flotation

Xuezhi Zhang, Pasquale Amendola, John C. Hewson, Milton Sommerfeld, Qiang Hu

Research output: Contribution to journalArticlepeer-review

121 Scopus citations


The effects of changes in cellular characteristics and dissolved organic matter (DOM) on dissolved air flotation (DAF) harvesting of Chlorella zofingiensis at the different growth phases were studied. Harvesting efficiency increased with Al 3+ dosage and reached more than 90%, regardless of growth phases. In the absence of DOM, the ratio of Al 3+ dosage to surface functional group concentration determined the harvesting efficiency. DOM in the culture medium competed with algal cell surface functional groups for Al 3+, and more Al 3+ was required for cultures with DOM than for DOM-free cultures to achieve the same harvesting efficiency. As the culture aged, the increase of Al 3+ dosage due to increased DOM was less than the decrease of Al 3+ dosage associated with reduced cell surface functional groups, resulting in overall reduced demand for Al 3+. The interdependency of Al 3+ dosage and harvesting efficiency on concentrations of cell surface functional groups and DOM was successfully modeled.

Original languageEnglish (US)
Pages (from-to)477-484
Number of pages8
JournalBioresource Technology
StatePublished - Jul 2012


  • Algal harvesting
  • Cell surface functional group
  • Coagulation
  • Dissolved organic matter
  • Model

ASJC Scopus subject areas

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal


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