The Rheology and Pumping of Thickened Activated Sludge

1983 ◽  
Vol 15 (1) ◽  
pp. 59-76 ◽  
Author(s):  
Ian H Rose-Innes ◽  
Steven Nossel
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Full Scale ◽  
Volume Index ◽  
Waste Activated Sludge ◽  
Sludge Volume Index ◽  
Rotational Viscometer ◽  
Sewage Treatment Plants ◽  
Flow Behaviour Index ◽  
Behaviour Index

The rheology of waste activated sludge (WAS) and of humus and digested sludges taken from full scale sewage treatment plants at solids concentrations between 1,5% and 9% (g/g) was investigated using a rotational viscometer. The results indicated that all the sludges behaved as pseudoplastic thixotropic fluids. The pseudo-plastic parameters, fluid consistency index K and flow behaviour index n, were related to concentration, and in the case of WAS to the sludge volume index (SVI). Concentration and SVI were found to be the most important variables. These relationships allow the prediction of resistency to flow in pipelines of WAS with various SVI values and of humus and digested sludges, within the range of solids concentrations tested.

Prediction of sludge volume index bulking using image analysis and neural network at a full-scale activated sludge plant

2015 ◽  
Vol 57 (37) ◽  
pp. 17195-17205 ◽  
Author(s):  
Halime Boztoprak ◽  
Yüksel Özbay ◽  
Dünyamin Güçlü ◽  
Murat Küçükhemek
Keyword(s):  
Neural Network ◽  
Image Analysis ◽  
Activated Sludge ◽  
Full Scale ◽  
Volume Index ◽  
Sludge Volume Index

Study on Characteristics of Activated Sludge at Low Temperature

2014 ◽  
Vol 675-677 ◽  
pp. 574-577
Author(s):  
Sheng Shu Ai ◽  
Xue Hua Zhang ◽  
Yan Bo Xiao ◽  
Xi Tian ◽  
De Jun Bian
Keyword(s):  
Low Temperature ◽  
Activated Sludge ◽  
Average Particle Size ◽  
Sewage Treatment ◽  
Volume Index ◽  
Average Particle ◽  
Activated Sludge Process ◽  
Sludge Volume Index ◽  
Urban Sewage ◽  
Settlement Ratio

The change rule of characteristics of activated sludge in urban sewage treatment by activated sludge process were investigated at low temperature of 15°C~3°C.The results showed that with the temperature decreased, average particle size and dehydrogenase activity showed a trend of decrease; sludge settlement ratio and sludge volume index and sludge extracellular polymeric substance showed a trend of increase.

Examples for the Upgrading of Existing Activated Sludge Plants for Nutrient Removal

1990 ◽  
Vol 22 (7-8) ◽  
pp. 113-121
Author(s):  
W. Maier
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
West Germany ◽  
Sewage Treatment Plants ◽  
Effluent Standards ◽  
Near Future

In view of the new effluent standards in West Germany, including nitrification and phosphorus elimination, many of the existing sewage treatment plants will have to be rebuilt or expanded. Another demand which will have to be dealt with in the near future is denitrification. Under consideration of the large BOD5-loads which were taken into account when designing the plants, many of them nitrify during the summer or can be easily converted to operate with nitrification. Principles for planning the upgrading of such plants have been laid down in order to achieve the required effluent concentrations. The application of these principles is demonstrated with examples of upgraded plants.

On-line measurements of settling characteristics in activated sludge

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).

Settling Characteristics of Activated Sludge in Danish Treatment Plants with Biological Nutrient Removal

1994 ◽  
Vol 29 (7) ◽  
pp. 157-165 ◽  
Author(s):  
Gert Holm Kristensen ◽  
Per Elberg Jørgensen ◽  
Per Halkjær Nielsen
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Volume Index ◽  
Biological Nutrient Removal ◽  
Sludge Volume Index ◽  
Filamentous Microorganisms ◽  
Best Parameter ◽  
One Year ◽  
Sludge Settling ◽  
Settling Characteristics

In 1989-91, a study was performed to investigate the settling characteristics of activated sludge in Danish treatment plants with biological nutrient removal. The study included three screening series on 38 treatment plants. Furthermore, the study included investigations during one year on seasonal variations in sludge settling characteristics at three treatment plants. The screening investigations were performed in November 1989 and May and September, 1990. Results showed that in the May-screening, 35-45% of the plants had a filament index of 2-2.5 or above, corresponding to a sludge volume index above 150 ml/g. When comparing data for diluted and non-diluted sludge volume indices, a SVI value of 150 ml/g seemed parallel to a DSVI of 110 ml/g. In the November- and September-screenings, some 30% of the plants had activated sludge showing a filament index in or above the critical area. Dominating filamentous microorganisms were found to be (in decreasing order): Microthrix parvicella, Type 0041, Type 021N, Type 0092, Type 0914, and Type 1851. A distinct variation over the year in sludge settling characteristics was found for the three plants. Sludge settling characteristics improved during summer, and deteriorated during winter. For activated sludge with a high content of filamentous microorganisms, the best parameter to follow the variations in sludge settling properties was the filament number. If the activated sludge concentration, the MLSS, varied significantly, the specific filament number was to be applied.

Thermochemical pretreatment in the anaerobic digestion of waste activated sludge

2002 ◽  
Vol 46 (10) ◽  
pp. 173-179 ◽  
Author(s):  
S. Tanaka ◽  
K. Kamiyama
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Waste Activated Sludge ◽  
Anaerobic Digesters ◽  
Thermochemical Pretreatment ◽  
Methane Production Rate

Effects of a thermochemical pretreatment on the anaerobic digestion of waste activated sludge (WAS) was investigated by semicontinuously-fed digesters operated at 37¡C. WAS from a return sludge line of a municipal sewage treatment plant was pretreated by autoclaving at 130°C for 5 minutes after adding 0.3g NaOH/g VSS. Solids of WAS were thermochemically solubilized to one half and then 60% or more were in totality solubilized in anaerobic digesters fed with pretreated WAS at 2-8 days of hydraulic retention times (HRT), while only 16-36% were solubilized in digesters fed with raw WAS. The adverse effect of the set temperature (130°C) on the biodegradability of protein was not found. As a result, removal rates of COD in digestion was increased from 38% to 57% at 8 days HRT by the pretreatment. A specific methane production rate in the pretreated process was three times as high as the normal process. The thermochemical pretreatment was found to be very effective to enhance biodegradability as well as solubilization of WAS in anaerobic digestion.

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