Describing Motion
350
© IWA Publishing 2013 Journal of Water Supply: Research and Technology—AQUA
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62.6
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2013
Behaviour of cyanobacterial bloom material following coagulation and/or sedimentation
Lionel Ho, Albane Barbero, Jennifer Dreyfus, David R. Dixon, Feng Qian,
Peter J. Scales and Gayle Newcombe
ABSTRACT
The global increase in detection of cyanobacteria and their metabolites has prompted greater emphasis in optimizing water treatment options for their effective removal. In particular, conventional coagulation and clarification processes have been shown to be effective in removing whole cyanobacterial cells, and consequently a majority of the metabolites. However, the resultant cyanobacterial-laden sludge is often not closely monitored in treatment plants. This study has shown that the sludge supernatant derived from the coagulation/sedimentation of a range of natural cyanobacterial blooms contained extremely high concentrations of metabolites (up to
∼8,000 ng L–1 of geosmin and ∼90 μg L–1 of microcystins), which was attributed to cell lysis.
Furthermore, the fate of the metabolites in the sludge supernatants differed with geosmin shown to be biodegradable, while the microcystins were released at different stages with some variants shown to be more persistent. The release and biodegradation of the metabolites followed pseudofirst-order kinetics with rate constants comparable to experiments using laboratory-cultured
Lionel Ho (corresponding author)
Albane Barbero
Jennifer Dreyfus
Gayle Newcombe
Australian Water Quality Centre, SA Water
Corporation,
250 Victoria Square,
Adelaide,
SA 5000,
Australia
E-mail: lionel.ho@sawater.com.au
David R. Dixon
Feng Qian
Peter J. Scales
Department of Chemical & Biomolecular
Engineering,
The University of Melbourne,
VIC 3010,
Australia
cyanobacteria. A key finding from this study was that the identification of cyanobacterial cell type is critical in making informed operational decisions,
© IWA Publishing 2013 Journal of Water Supply: Research and Technology—AQUA
|
62.6
|
2013
Behaviour of cyanobacterial bloom material following coagulation and/or sedimentation
Lionel Ho, Albane Barbero, Jennifer Dreyfus, David R. Dixon, Feng Qian,
Peter J. Scales and Gayle Newcombe
ABSTRACT
The global increase in detection of cyanobacteria and their metabolites has prompted greater emphasis in optimizing water treatment options for their effective removal. In particular, conventional coagulation and clarification processes have been shown to be effective in removing whole cyanobacterial cells, and consequently a majority of the metabolites. However, the resultant cyanobacterial-laden sludge is often not closely monitored in treatment plants. This study has shown that the sludge supernatant derived from the coagulation/sedimentation of a range of natural cyanobacterial blooms contained extremely high concentrations of metabolites (up to
∼8,000 ng L–1 of geosmin and ∼90 μg L–1 of microcystins), which was attributed to cell lysis.
Furthermore, the fate of the metabolites in the sludge supernatants differed with geosmin shown to be biodegradable, while the microcystins were released at different stages with some variants shown to be more persistent. The release and biodegradation of the metabolites followed pseudofirst-order kinetics with rate constants comparable to experiments using laboratory-cultured
Lionel Ho (corresponding author)
Albane Barbero
Jennifer Dreyfus
Gayle Newcombe
Australian Water Quality Centre, SA Water
Corporation,
250 Victoria Square,
Adelaide,
SA 5000,
Australia
E-mail: lionel.ho@sawater.com.au
David R. Dixon
Feng Qian
Peter J. Scales
Department of Chemical & Biomolecular
Engineering,
The University of Melbourne,
VIC 3010,
Australia
cyanobacteria. A key finding from this study was that the identification of cyanobacterial cell type is critical in making informed operational decisions,