Measurement of activated sludge particle diameters using laser diffraction method / Pomiary średnicy cząstek osadu czynnego za pomocą metody dyfrakcji laserowej (original) (raw)
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Water
Physicochemical studies on wastewater quality and microscopic analyses of activated sludge are necessary to properly evaluate the condition of activated sludge. The aim of this study was to evaluate the application of the sludge biotic index to determine when a change in treatment quality is short-lived, caused by, e.g., a change in influent quality or quantity, and when it indicates adverse changes in the biocenosis of activated sludge, which would very likely result in the lower efficiency of wastewater treatment in the near future. The objects of the study were two identical parallel running small wastewater treatment plants. The following indicators of contamination were analyzed: the chemical oxygen demand (COD), biochemical oxygen demand (BOD 5), and total suspended solids (TSS). The authors additionally carried out a microscopic analysis. The study confirmed a correlation between the sludge biotic index and the removal efficiency of COD and BOD 5 ; however, no correlation was found between the sludge biotic index and the removal efficiency of total suspended solids. The presence of metazoan microorganisms coincided in time with a good effluent treatment efficiency. When their quantity declined, a decrease in the efficiency of wastewater treatment was also observed.
The fundamentals of wastewater sludge characterization and filtration
Water Science & Technology
The move to greater emphasis on the disposal of wastewater sludges through routes such as incineration and the added cost of landfill emplacement puts high demands on dewatering technology for these sludges. A clear problem in this area is that wastewater sludges are slow and difficult to dewater and traditional methods of laboratory measurement for prediction of filtration performance are inadequate. This is highly problematic for the design and operational optimisation of centrifuges, filters and settling devices in the wastewater industry. The behaviour is assessed as being due to non-linear behaviour of these sludges which negates the use of classical approaches. These approaches utilise the linear portion of a t versus V2 plot (where t is the time to filtration and V is the specific filtrate volume) to extract a simple Darcian permeability. Without this parameter, a predictive capacity for dewatering using current theory is negated.
Fundamental aspects of sludge characterization
1996
DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Characterization of sewage sludges : fundamentals and results
1993
DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Characterization of sewage sludge from different treatment systems
Anais do Congresso de Iniciação Científica da Unicamp, 2015
The Vacuum Filtration and the Capillary Suction Time tests can be used for coagulant dosage evaluation. The tests indicate that there is an optimal range of synthetic polymer dosage to ensure the best performance of the coagulated sludge compared to the raw sludge. Tests with FeCl3 indicate that increasing the coagulant dose decreases time for sludge filtration.
Morphological Analysis of Activated Sludge Flocs and Filaments
Purification of waste water is commonly done using the activated sludge process. The ratio of the activated sludge flocs and filamentous bacteria play a key role in the purification process of waste water. The sludge bulking or filamentous bulking is a common problem in activated sludge plants that prevents flocs to settle down. Digital imaging techniques can play an important role in monitoring activated sludge flocs and filaments in waste water treatment plants (WWTPs). In this paper, an algorithm to segment the flocs and the filaments of the microscopic sludge images captured at 4 times magnification in brightfield microscopy has been proposed. Morphological parameters, like, compactness, roundness, convexity, equivalent diameter are analyzed. Comparison with laser particle size analysis method has been done for the interpretation of the imaging results.
SLUDGE PROCESSING AND DISPOSAL CHARACTERIZATION AND SOURCES OF SLUDGES FROM WASTEWATER TREATMENT
The main objective of wastewater treatment is to reduce the pollution load on receiving waters. The treatment processes concentrate some of the impurities in a sludge along with the microbial excess biomass. Water treatment also produces a sludge from the chemical coagulation and separation of impurities. The treatment and disposal of these sludges should be considered as an integral part of the treatment process. The treatment processes should be regarded therefore as a lowsolids stream (effluent or drinking water) and a highsolids stream (sludge).
2018
In activated sludge (AS) process, the impact of the operational parameters on process efficiency is assumed to be correlated with the sludge properties. This study provides a better insight into these interactions by subjecting a laboratory-scale AS system to a sequence of operating condition modifications enabling typical situations of a wastewater treatment plant to be represented. Process performancewas assessed and AS flocmorphology (size, circularity, convexity, solidity and aspect ratio) was quantified by measuring 100,000 flocs per sample with an automated image analysis technique. Introducing 3D distributions, which combine morphological properties, allowed the identification of a filamentous bulking characterized by a floc population shift towards larger sizes and lower solidity and circularity values. Moreover, a washout phenomenon was characterized by smaller AS flocs and an increase in their solidity. Recycle ratio increase and COD:N ratio decrease both promoted a slight...
Laser diffraction method is one of recently applied method for measurement of active sludge particles size distribution. This method requires mixing of the suspension and then pumping it through the measurement unit. Energy of mixing and process of pumping may destroy flocks of the active sludge and change its properties during the measurement. Thus, stabilization of the active sludge flocks before measurement is required. The purpose of this paper was to determine the possibility of flocks sample stabilization for measurements with application of laser diffraction method. This stabilization should allow comparison of various sludge flocks’ diameters, obtained in different conditions. Resuming our results, we may state that according to practical application, usage of stabilization based on ultrasounds was sufficient. However, in order to obtain the replicable results for various types of the active sludge it is necessary to precise describe the ultrasound energy provided to flocks ...