Characterisation of activated sludge by automated image analysis

An automated image analysis procedure has been developed for the simultaneous characterisation of flocs (projected diameter and fractal dimension) and filamentous bacteria (filament length) of fresh activated sludge samples observed by optical microscopy. It has been used to monitor, over a period of 1 year, the activated sludge of a large municipal wastewater treatment plant, located in an area subject to mild continental weather. No relationship could be established between floc characteristics and the sludge volume index (SVI). Filamentous bulking events associated with variations of the SVI were detected from changes of total filament length, of filament number/image and of the proportion of filamentous bacteria with respect to the total activated sludge. The proposed automated method provides quantitative support for the classification of bulking events.

[1]  M. Pons,et al.  Biomass quantification by image analysis. , 2000, Advances in biochemical engineering/biotechnology.

[2]  Willy Verstraete,et al.  Image analysis to estimate the settleability and concentration of activated sludge , 1997 .

[3]  S. Rossetti,et al.  Survey on the Occurrence of Filamentous Organisms in Municipal Wastewater Treatment Plants Related to Their Operating Conditions , 1994 .

[4]  Bruce E. Logan,et al.  Fractal dimensions of marine snow determined from image analysis of in situ photographs , 1994 .

[5]  Ying Liu,et al.  Characterizing the Structure of Abrasive Fineparticles , 1992 .

[6]  G. Daigger,et al.  Manual on the causes and control of activated sludge bulking and foaming , 1992 .

[7]  J. Ganczarczyk,et al.  Fractal geometry of particle aggregates generated in water and wastewater treatment processes , 1989 .

[8]  M Casellas,et al.  Use of image analysis and rheological studies for the control of settleability of filamentous bacteria: application in SBR reactor. , 2001, Water science and technology : a journal of the International Association on Water Pollution Research.

[9]  John C. Russ,et al.  The image processing handbook (3. ed.) , 1995 .

[10]  J. Wanner,et al.  A national survey of activated sludge separation problems in the Czech Republic: filaments, floc characteristics and activated sludge metabolic properties , 1998 .

[11]  M. Tackx,et al.  The Geometric Features, Shape Factors and Fractal Dimensions of Suspended Particulate Matter in the Scheldt Estuary (Belgium) , 1999 .

[12]  P. Madoni.  Survey of filamentous microorganisms from bulking and foaming activated-sludge plants in Italy , 2000 .

[13]  Å. Westlund,et al.  Bulking and foaming caused by microthrix parvicella at three large sewage treatment plants in the greater stockholm area , 1996 .

[14]  Eugénio C. Ferreira,et al.  Characterisation by image analysis of anaerobic sludge under shock conditions , 2000 .

[15]  D. Jenkins,et al.  Relationship between organic loading, dissolved oxygen concentration and sludge settleability in the completely-mixed activated sludge process. , 1980 .

[16]  Xiao-yan Li,et al.  Size distributions and fractal properties of particles during a simulated phytoplankton bloom in a mesocosm , 1995 .

[17]  A. Andreadakis,et al.  Survey of filamentous populations in nutrient removal plants in four European countries , 1998 .

[18]  Michael Wagner,et al.  Probing Activated Sludge with Fluorescently Labeled rRNA Targeted Oligonucleotides , 1994 .

[19]  G. Gaval,et al.  Influence of transient substrate overloads on the proliferation of filamentous bacterial populations in an activated sludge pilot plant. , 2001, Water research.

[20]  M. Pons,et al.  Automated monitoring of activated sludge in a pilot plant using image analysis. , 2001, Water science and technology : a journal of the International Association on Water Pollution Research.

[21]  R. Pujol,et al.  Biosorption and dynamics of bacterial populations in activated sludge , 1992 .

[22]  W. Verstraete,et al.  A sensor for the secondary clarifier based on image analysis. , 1996 .