Impact of sonication at 20kHz on Microcystis aeruginosa, Anabaena circinalis and Chlorella sp.

Pradeep Rajasekhar, Linhua Fan, Thang Nguyen, Felicity A. Roddick

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Blooms of toxic cyanobacteria such as Microcystis aeruginosa periodically occur within wastewater treatment lagoons in the warmer months, and may consequently cause contamination of downstream water and outages of the supply of recycled wastewater. Lab-scale sonication (20kHz) was conducted on suspensions of M. aeruginosa isolated from a wastewater treatment lagoon, and two other algal strains, Anabaena circinalis and Chlorella sp., to investigate cell reduction, growth inhibition, release of microcystin and sonication efficiency in controlling the growth of the M. aeruginosa. For M. aeruginosa, for all sonication intensities and exposure times trialled, sonication led to an immediate reduction in the population, the highest reduction rate occurring within the initial 5min. Sonication for 5min at 0.32W/mL, or for a longer exposure time (>10min) at a lower power intensity (0.043W/mL), led to an immediate increase in microcystin level in the treated suspensions. However, prolonged exposure (>10min) to sonication at higher power intensities reduced the microcystin concentration significantly. Under the same sonication conditions, the order of decreasing growth inhibition of the three algal species was: A. circinalis>. M. aeruginosa>. Chlorella sp., demonstrating sonication has the potential to selectively remove/deactivate harmful cyanobacteria from the algal communities in wastewater treatment lagoons.

Original languageEnglish
Pages (from-to)1473-1481
Number of pages9
JournalWater Research
Issue number5
Publication statusPublished - 1 Apr 2012
Externally publishedYes


  • Anabaena circinalis
  • Chlorella sp.
  • Lagoon-treated wastewater
  • Microcystin
  • Microcystis aeruginosa
  • Sonication

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