C12-HSL is an across-boundary signal molecule that could alleviate fungi Galactomyces's filamentation: A new mechanism on activated sludge bulking

2021 ◽  
pp. 111823
Author(s):  
Xin Lu ◽  
Yue Wang ◽  
Congli Chen ◽  
Zhixuan Feng ◽  
Yang Huo ◽  
...  
1989 ◽  
Vol 21 (6-7) ◽  
pp. 609-619 ◽  
Author(s):  
Y.-J. Shao ◽  
David Jenkins

Laboratory and pilot plant experiments on anoxic selector activated sludge systems were conducted on two wastewaters in some cases supplemented with nitrate, acetate or glucose. To prevent bulking sufficient anoxic selector detention time and nitrate levels must be available to reduce selector effluent soluble COD to below 100 mg/l and to reduce readily metabolizable organic matter to virtually zero (< 1 mg/l). Soluble COD/NO3-N removal stoichiometry is in the range 6.0-6.7. Selector systems have elevated soluble substrate removal and denitrification rates compared to CSTR systems. These rates are not affected greatly by temperature (20-25°C) for CSTR sludges but are for selector sludges. Upon exhaustion of nitrate in a selector soluble COD leaks out of the activated sludge in significant amounts. Thiothrix sp. and type 021N denitrify only to NO2 and at much slower rates than Zoogloearamigera does to N2. A sequencing batch system provides an optimistic estimate of the SVI that can be obtained by an anoxic selector system.


2007 ◽  
Vol 41 (19) ◽  
pp. 4349-4356 ◽  
Author(s):  
Andrew J. Schuler ◽  
David Jassby

1992 ◽  
Vol 25 (6) ◽  
pp. 215-230 ◽  
Author(s):  
David Jenkins

The physiological properties of filamentous and floc-forming microorganisms found in activated sludge are reviewed. From this review four model microorganisms - two floc formers and two filamentous organisms - are proposed for use in an activated sludge model that predicts activated sludge “quality”.


Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1941 ◽  
Author(s):  
Bartosz Szeląg ◽  
Jakub Drewnowski ◽  
Grzegorz Łagód ◽  
Dariusz Majerek ◽  
Ewa Dacewicz ◽  
...  

The paper presented the methodology for the construction of a soft sensor used for activated sludge bulking identification. Devising such solutions fits within the current trends and development of a smart system and infrastructure within smart cities. In order to optimize the selection of the data-mining method depending on the data collected within a wastewater treatment plant (WWTP), a number of methods were considered, including: artificial neural networks, support vector machines, random forests, boosted trees, and logistic regression. The analysis conducted sought the combinations of independent variables for which the devised soft sensor is characterized with high accuracy and at a relatively low cost of determination. With the measurement results pertaining to the quantity and quality of wastewater as well as the temperature in the activated sludge chambers, a good fit can be achieved with the boosted trees method. In order to simplify the selection of an optimal method for the identification of activated sludge bulking depending on the model requirements and the data collected within the WWTP, an original system of weight estimation was proposed, enabling a reduction in the number of independent variables in a model—quantity and quality of wastewater, operational parameters, and the cost of conducting measurements.


1994 ◽  
Vol 29 (7) ◽  
pp. 289-294 ◽  
Author(s):  
S. Kunst ◽  
M. Reins

Six processes implemented at treatment plants with biological phosphorus removal aiming to avert sludge bulking were examined systematically. Intensive observation of the filamentous microorganisms (characterised according to a new scheme) and microscopic observation of sludge structures are used to identify the significant organisms and their bulking behaviour.


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