Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis

Markus Schmid; Antoine Thill; Ulrike Purkhold; Marion Walcher; Jean Yves Bottero; Philippe Ginestet; Per Halkjær Nielsen; Stefan Wuertz; Michael Wagner

doi:10.1016/S0043-1354(02)00616-4

Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis

Markus Schmid, Antoine Thill, Ulrike Purkhold, Marion Walcher, Jean Yves Bottero, Philippe Ginestet, Per Halkjær Nielsen^*, Stefan Wuertz, Michael Wagner

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

103 Citations (Scopus)

Abstract

In this study we present a new approach to determine volumes, heterogeneity factors, and compositions of the bacterial population of activated sludge flocs by 3D confocal imaging. After staining the fresh flocs with fluorescein-isothiocyanate, 75 stacks of images (containing approx. 3000 flocs) were acquired with a confocal laser scanning microscope. The self-developed macro 3D volume and surface determination for the KS 400 software package combined the images of one stack to a 3D image and calculated the real floc volume and surface. We determined heterogeneity factors like the ratio of real floc surface to the surface of a sphere with the respective volume and the fractal dimension (D_f). According to their significant influence on floc integrity and quality, we also investigated the chemical composition of flocs and quantified their bacterial population structure by using group-specific rRNA-targeted probes for fluorescence in situ hybridization. By a settling experiment we enriched flocs with poor settling properties and determined the above-mentioned parameters. This approach revealed shifts in floc volume, heterogeneity, and bacterial and chemical composition according to the settling quality of the flocs.

Original language	English
Pages (from-to)	2043-2052
Number of pages	10
Journal	Water Research
Volume	37
Issue number	9
DOIs	https://doi.org/10.1016/S0043-1354(02)00616-4
Publication status	Published - May 2003
Externally published	Yes

ASJC Scopus Subject Areas

Environmental Engineering
Civil and Structural Engineering
Ecological Modelling
Water Science and Technology
Waste Management and Disposal
Pollution

Keywords

Confocal laser scanning microscopy (CLSM)
Floc characterization
Fluorescence in situ hybridization (FISH)
Sludge settling

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10.1016/S0043-1354(02)00616-4

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title = "Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis",

abstract = "In this study we present a new approach to determine volumes, heterogeneity factors, and compositions of the bacterial population of activated sludge flocs by 3D confocal imaging. After staining the fresh flocs with fluorescein-isothiocyanate, 75 stacks of images (containing approx. 3000 flocs) were acquired with a confocal laser scanning microscope. The self-developed macro 3D volume and surface determination for the KS 400 software package combined the images of one stack to a 3D image and calculated the real floc volume and surface. We determined heterogeneity factors like the ratio of real floc surface to the surface of a sphere with the respective volume and the fractal dimension (Df). According to their significant influence on floc integrity and quality, we also investigated the chemical composition of flocs and quantified their bacterial population structure by using group-specific rRNA-targeted probes for fluorescence in situ hybridization. By a settling experiment we enriched flocs with poor settling properties and determined the above-mentioned parameters. This approach revealed shifts in floc volume, heterogeneity, and bacterial and chemical composition according to the settling quality of the flocs.",

keywords = "Confocal laser scanning microscopy (CLSM), Floc characterization, Fluorescence in situ hybridization (FISH), Sludge settling",

author = "Markus Schmid and Antoine Thill and Ulrike Purkhold and Marion Walcher and Bottero, \{Jean Yves\} and Philippe Ginestet and Nielsen, \{Per Halkj{\ae}r\} and Stefan Wuertz and Michael Wagner",

year = "2003",

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doi = "10.1016/S0043-1354(02)00616-4",

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AU - Schmid, Markus

AU - Thill, Antoine

AU - Purkhold, Ulrike

AU - Walcher, Marion

AU - Bottero, Jean Yves

AU - Ginestet, Philippe

AU - Nielsen, Per Halkjær

AU - Wuertz, Stefan

AU - Wagner, Michael

PY - 2003/5

Y1 - 2003/5

N2 - In this study we present a new approach to determine volumes, heterogeneity factors, and compositions of the bacterial population of activated sludge flocs by 3D confocal imaging. After staining the fresh flocs with fluorescein-isothiocyanate, 75 stacks of images (containing approx. 3000 flocs) were acquired with a confocal laser scanning microscope. The self-developed macro 3D volume and surface determination for the KS 400 software package combined the images of one stack to a 3D image and calculated the real floc volume and surface. We determined heterogeneity factors like the ratio of real floc surface to the surface of a sphere with the respective volume and the fractal dimension (Df). According to their significant influence on floc integrity and quality, we also investigated the chemical composition of flocs and quantified their bacterial population structure by using group-specific rRNA-targeted probes for fluorescence in situ hybridization. By a settling experiment we enriched flocs with poor settling properties and determined the above-mentioned parameters. This approach revealed shifts in floc volume, heterogeneity, and bacterial and chemical composition according to the settling quality of the flocs.

AB - In this study we present a new approach to determine volumes, heterogeneity factors, and compositions of the bacterial population of activated sludge flocs by 3D confocal imaging. After staining the fresh flocs with fluorescein-isothiocyanate, 75 stacks of images (containing approx. 3000 flocs) were acquired with a confocal laser scanning microscope. The self-developed macro 3D volume and surface determination for the KS 400 software package combined the images of one stack to a 3D image and calculated the real floc volume and surface. We determined heterogeneity factors like the ratio of real floc surface to the surface of a sphere with the respective volume and the fractal dimension (Df). According to their significant influence on floc integrity and quality, we also investigated the chemical composition of flocs and quantified their bacterial population structure by using group-specific rRNA-targeted probes for fluorescence in situ hybridization. By a settling experiment we enriched flocs with poor settling properties and determined the above-mentioned parameters. This approach revealed shifts in floc volume, heterogeneity, and bacterial and chemical composition according to the settling quality of the flocs.

KW - Confocal laser scanning microscopy (CLSM)

KW - Floc characterization

KW - Fluorescence in situ hybridization (FISH)

KW - Sludge settling

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Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis

Abstract

ASJC Scopus Subject Areas

Keywords

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