Study of filamentous bacteria by image analysis and relation with settleability

An automated procedure for the characterisation by image analysis of the morphology of activated sludge has been used to monitor the biomass in a pilot wastewater treatment plant during two runs inoculated with a different sludge and operated at two different temperatures. The bulking events were easily detected by image analysis. Correlations were found between settleability properties (Sludge Volume Index and settling velocity) and the morphological parameters (filament total length, filament number and floc size).

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Automated monitoring of activated sludge in a pilot plant using image analysis

Water Science & Technology ◽

10.2166/wst.2001.0397 ◽

2001 ◽

Vol 43 (7) ◽

pp. 91-96 ◽

Cited By ~ 21

Author(s):

M. da Motta ◽

M. N. Pons ◽

N. Roche

Keyword(s):

Image Analysis ◽

Wastewater Treatment ◽

Activated Sludge ◽

Size Distribution ◽

Wastewater Treatment Plant ◽

Pilot Plant ◽

Settling Velocity ◽

Treatment Plant ◽

Volume Index ◽

Sludge Volume Index

An automated procedure for the characterisation by image analysis of the morphology of activated sludge has been used to monitor the biomass in a pilot wastewater treatment plant, in complement to the usual settleability (sludge volume index, settling velocity) and size distribution (by laser granulometry) measurements.

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Use of image analysis and rheological studies for the control of settleability of filamentous bacteria: application in SBR reactor

Water Science & Technology ◽

10.2166/wst.2001.0115 ◽

2001 ◽

Vol 43 (3) ◽

pp. 27-33 ◽

Cited By ~ 16

Author(s):

C. Dagot ◽

M. N. Pons ◽

M. Casellas ◽

G. Guibaud ◽

P. Dollet ◽

...

Keyword(s):

Image Analysis ◽

Sequencing Batch Reactor ◽

Batch Reactor ◽

Automated Image Analysis ◽

Volume Index ◽

Filamentous Bacteria ◽

Sludge Volume Index ◽

Floc Size ◽

First Results

To monitor the ability of flocs to settle in Sequencing Batch Reactor sludge, two methods were tested during two operation cycles. Firstly, an automated image analysis procedure has been tested to quantify the floc size and the length and number of filaments. Secondly, rheological measurements (Bingham viscosity and shear stress) have been used to characterise the dispersion of the sludge which can reflect the cohesive strength of aggregates and so the influence of filamentous bacteria on rheological properties. These results were compared with settling parameters such as Sludge Volume Index or settling velocity. Correlations between the measured parameters with image analysis and parameters such as Sludge Volume Index have been obtained. If it is more difficult to analyze rheological results, it seems however that the thixotropy and the Bingham viscosity distinguish poor settlement owing to some filamentous bulking. The first results are promising, although they require confirmation in the long term.

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Characterization of Filamentous Flocs to Predict Sedimentation Parameters Using Image Analysis

Journal of Sensors ◽

10.1155/2020/5248509 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

M. A. Molina ◽

Claudio Abraham Acuña Pérez ◽

C. A. Leiva

Keyword(s):

Image Analysis ◽

Wastewater Treatment ◽

Settling Velocity ◽

Wastewater Treatment Plants ◽

Research Work ◽

Treatment Plant ◽

Optical Microscope ◽

Filamentous Bacteria ◽

Fall Velocity

In wastewater treatment plants, the degradation of complex substances that contaminate water is carried out by microorganisms, which are fixed by a network formed by filamentous bacteria, creating large flocs that settle easily. However, the excessive growth of said bacteria causes a series of drawbacks such as the reduction of settling velocity, leakage of activated sludge with the effluent, and formation of supernatant, a phenomenon known as bulking. This research work seeks to develop and evaluate a procedure for the physical characterization of the flocs to determine the parameters that affect the settling velocity and thereby detect and control bulking. For this purpose, sedimentation and image analysis tests were carried out from wastewater from the Aguas Antofagasta treatment plant (Chile). The image analysis was performed with images captured from an optical microscope in two magnifications (100x and 50x), which were analyzed by marking each floc individually and characterized by an image processing software. Additionally, sedimentation tests were performed on columns (area of 74 (cm2) and height of 70 (cm)). As a result, an inversely proportional dependence was found on the settling velocity evaluated by the Vesilind equation in the zone of constant fall velocity with respect to the number of flocs connected per cluster, giving an estimate of the settling velocity depending on the number of flocs connected. This would allow predicting settling velocity with image analysis, taking into account that the problem of bulking is determined by the type of filamentous bacteria that causes it and the sedimentation process is affected in large part by local factors. It can be concluded through this study that as the number of flocs connected per cluster increases, the settling velocity decreases. This study provides wastewater treatment plants with a practical tool to determine sedimentation times and thus improve the quality of the treated water, avoiding problems of flocs leaking with the effluent. In addition, the image analysis itself allows rapid detection of the phenomenon of bulking and its severity.

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Filamentous bacterial population dominance in activated sludges subject to stresses

Water Science & Technology ◽

10.2166/wst.2002.0455 ◽

2002 ◽

Vol 46 (1-2) ◽

pp. 49-53 ◽

Cited By ~ 3

Author(s):

G. Gaval ◽

P. Duchène ◽

J.-J. Pernelle

Keyword(s):

Wastewater Treatment ◽

In Situ Hybridization ◽

Fluorescent In Situ Hybridization ◽

Bacterial Population ◽

Filamentous Growth ◽

Volume Index ◽

Filamentous Bacteria ◽

Sludge Volume Index ◽

The One

Evolution of a filamentous bacterial population was monitored on four wastewater treatment pilot plants subject to stresses which have consisted of oxygen deficiencies and/or loading shocks. Fluorescent in situ hybridization (FISH) was used to perform filaments identification and quantification. Results obtained on the different pilot plants have led us to conclude that independently of the nature of the stresses, a single filamentous bacteria species was involved in the increase of the sludge volume index associated to the filamentous growth. In addition, when serial stresses were used, substitutions in dominant filamentous populations occurred: if another filament began to proliferate it caused the regression of the one which dominant.

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Ten Years Experience with a Highly Loaded Activated Sludge Plant

Water Science & Technology ◽

10.2166/wst.1984.0034 ◽

1984 ◽

Vol 16 (12) ◽

pp. 649-660

Author(s):

P Balmér ◽

S Hallquist ◽

M Hernebring

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Residence Time ◽

Suspended Solids ◽

Treatment Plant ◽

Volume Index ◽

Sludge Volume Index ◽

Solids Concentration ◽

Cell Residence Time ◽

Highly Loaded

The Rya wastewater treatment plant in Gothenburg, Sweden serves 640 000 population equivalents. It is an extremely highly loaded activated sludge plant without presetting with a mean cell residence time of about 0.5 days. Ten years experience proves that the plant is capable of removing about 70% of the BOD load. The effluent BOD is mainly caused by non settleable suspended solids due to the partly dispersed growth of the activated sludge. The low mean cell residence time and the high suspended solids concentration in the aeration basin influent gives an activated sludge with low viability and in mass balance studies it was determined that only 12% of the influent COD and about 40% of the BOD was oxidized by the activated sludge. The activated sludge has consistently had a very low sludge volume index and the settling basins could thus be very highly loaded. The surplus activated sludge could be thickened to solids concentrations over 6%. After dewatering the sludge was either lime treated or co-composted with bark. The plant is manned only eight hours five days a week. During unmanned time there are standby personnel. Data is presented on man power, energy and chemical use, and on costs.

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Application of the model of sludge volume index forecasting to assess reliability and improvement of wastewater treatment plant operating conditions

10.5004/dwt.2019.23370 ◽

2019 ◽

Vol 140 ◽

pp. 143-154 ◽

Cited By ~ 1

Author(s):

Bartosz Szeląg ◽

Krzysztof Barbusiński ◽

Jan Studziński

Keyword(s):

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Operating Conditions ◽

Volume Index ◽

Sludge Volume Index

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On-line measurements of settling characteristics in activated sludge

Water Science & Technology ◽

10.2166/wst.1997.0144 ◽

1997 ◽

Vol 36 (4) ◽

pp. 307-312

Author(s):

Michael R. Rasmussen ◽

Torben Larsen

Keyword(s):

Activated Sludge ◽

Settling Velocity ◽

Continuous Measurement ◽

Batch Reactor ◽

Volume Index ◽

Sludge Volume Index ◽

Dynamic Variations ◽

On Line ◽

Settling Column ◽

Settling Characteristics

An on-line settling column for measuring the dynamic variations of settling velocity of activated sludge has been developed. The settling column is automatic and self-cleansing insuring continuous and reliable measurements. The settling column was tested on sludge from a batch reactor where sucrose was added as an impulse to activated sludge. The continuous measurement of settling velocity revealed a highly dynamic response after the sucrose was added. The results were verified with simultaneous measurement of the initial settling rate. A 200 hour experiment showed variations in settling velocity, which was not apparent in the DSVI (Diluted Sludge Volume Index).

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Characteristics of the Coagulate Obtained During the Process of Model Wastewater Treatment

Environment Technology Resources Proceedings of the International Scientific and Practical Conference ◽

10.17770/etr2013vol1.799 ◽

2015 ◽

Vol 1 ◽

pp. 9

Author(s):

Julija Brovkina ◽

Galija Shulga ◽

Jurijs Ozolins ◽

Zilgma Irbe ◽

Maris Turks ◽

...

Keyword(s):

Wastewater Treatment ◽

Volume Index ◽

Optimal Time ◽

Sludge Volume Index ◽

Organic Part ◽

Main Drawback ◽

Average Size ◽

By Products ◽

Polyaluminium Chloride

In the process of wastewater treatment by coagulation a large amount of sediment is being produced, which is the main drawback of this method. Therefore, the development of utilization or recirculation technology of the waste obtained, the research of the obtained by-products should be conducted. Within the scope of this work, the sediment, that is being formed during the coagulation of the model wastewater containing the wood originated pollutants, was studied. Using the aluminium-containing composition coagulant on a base of polyaluminium chloride, coagulates characterized by the low sludge volume index within 30 minutes (89 ml g-1), and the optimal time of sedimentation is 20-30 minutes. The coagulate particles have an average size of 45.8 μm. The derived coagulate is composed primarily of carbon (27.9%), oxygen (49.4%) and aluminum (10.9%). Carbon, oxygen and hydrogen belong to an organic part of coagulate-the wood pollutants, which, in turn, has a high content of hemicellulose. It is concluded that the existing hemicellulose in the obtained coagulate is characterized by O-acetyl-4-O-methyl-D-glucuron-β-D-xylan with β-(1-4)-glucomannose.

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Promotion of nitrifiers through side-stream bioaugmentation: a full-scale study

Water Science & Technology ◽

10.2166/wst.2016.340 ◽

2016 ◽

Vol 74 (7) ◽

pp. 1736-1743 ◽

Cited By ~ 1

Author(s):

F. Stenström ◽

J. la Cour Jansen

Keyword(s):

Wastewater Treatment ◽

Efficient Method ◽

Load Capacity ◽

Treatment Plant ◽

Full Scale ◽

Nitrification Rate ◽

Flow Rates ◽

Nitrogen Loads ◽

Side Stream ◽

Different Temperatures

Bioaugmentation of nitrifiers from a side-stream treatment is an efficient method for boosting the mainstream process at a wastewater treatment plant (WWTP). Although this technology has been known for several years, the number of full-scale applications for it is limited. For a WWTP approaching its critical nitrogen load capacity, the benefits are doubled if the introduced side-stream treatment for digester supernatant is combined with bioaugmentation. Not only is the nitrogen load to the mainstream process decreased by 10–25%, but the mainstream process is also boosted with nitrifiers, increasing the nitrifying capacity. In this full-scale study, the increment of the nitrification rate is examined in the mainstream process at different temperatures and at different flow rates of returned activated sludge to the side-stream treatment. Our results show that the nitrification rate in the mainstream process was increased by 41% during the coldest period of the study, implying that the examined WWTP could treat considerably higher nitrogen loads if bioaugmentation were permanently installed.

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