Enhancement of biomass concentration in activated sludge systems

1995 ◽  
Vol 32 (7) ◽  
pp. 151-157
Author(s):  
R. Plaβ ◽  
I. Sekoulov
Keyword(s):  
Activated Sludge ◽  
Waste Water Treatment ◽  
Stable Process ◽  
Biomass Concentration ◽  
Air Bubbles ◽  
Volume Loading ◽  
Secondary Clarifier ◽  
Additional Charge ◽  
Complete Nitrification ◽  
Activated Sludge Systems

By installation of lamella in the activated sludge tank an increase of biomass concentration in the activated sludge tank can be achieved without additional charge of the secondary clarifier. Integrated packages of lamella which are installed in the discharge of the activated sludge tank at an angle of 60° effect a partial sedimentation and so a MLSS-preseparation. The MLSS in the activated sludge tank (influent of the lamella construction) was 6.5 g/l, the MLSS in the influent to the final clarifier (effluent of the lamella) was 3.1 g/l. That means that the lamella increased the MLSS concentration in the activated sludge tank by a factor of two. Despite a volume loading of 1.24 kg BOD5/(kg MLSS • d) a complete nitrification could be obtained. For ensuring a stable process and a balanced concentration of the biomass in the influent of the secondary clarifier, the preseparation of solids in the lamella is controlled by addition of air bubbles. By the enhancement of biomass concentration using this preseparation device, the extension of waste water treatment plants can be carried out with lower investment costs.

Nitrification Kinetics in Single-Sludge Biological Nutrient Removal Activated Sludge Systems

1992 ◽  
Vol 25 (6) ◽  
pp. 195-214 ◽  
Author(s):  
C. W. Randall ◽  
V. M. Pattarkine ◽  
S. A. McClintock
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Biomass Concentration ◽  
Biological Nutrient Removal ◽  
Mixed Liquor ◽  
Nitrification Kinetics ◽  
Anoxic Zones ◽  
Complete Nitrification ◽  
Activated Sludge Systems

Nitrification kinetics as a function of mixed liquor temperature were compared for a conventional fully-aerobic activated sludge system and a system accomplishing biological nutrient removal (BNR) by incorporation of anaerobic and anoxic zones using the UCT configuration. The systems treated the same municipal wastewater and both had flow rates of 151 L/day. The nitrification rates were greater in the nutrient removal system compared to the conventional system as long as the aerobic MCRT was above the minimum for complete nitrification. It was concluded that BNR systems require less aerobic volume than fully aerobic systems to accomplish nitrification because the aerobic biomass concentration is greater in the BNR systems, particularly if the UCT configuration is used. Nonetheless, BNR systems require more total volume to accomplish complete nitrification than fully aerobic systems, and the volume differential increases as mixed liquor temperatures decrease.

Nitrogen removal in activated sludge systems including denitrification in secondary clarifiers

1994 ◽  
Vol 30 (6) ◽  
pp. 101-111 ◽  
Author(s):  
H. Siegrist ◽  
W. Gujer
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Retention Time ◽  
Secondary Clarifier ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Activated Sludge Systems

Denitrification in the secondary clarifier can contribute substantially to the nitrogen removal of activated sludge systems. This is illustrated on two treatment plants with different secondary clarifier systems. A model to estimate denitrification capacity and to design activated sludge systems for nitrogen removal is developed and verified with data from two treatment plants. The model includes denitrification in the secondary clarifier, wastewater composition (soluble readily biodegradable COD, particulate degradable COD), oxygen input into the anoxic volume, temperature, and solids retention time (SRT). The influence of aerated grit chambers and primary sedimentation on denitrification is discussed.

Performance Increase of Papermill Waste Water Treatment Plants by a High-Capacity Trickling Filter Inserted as First Biological Stage

1990 ◽  
Vol 22 (7-8) ◽  
pp. 217-223 ◽  
Author(s):  
C. H. Möbius ◽  
I. Demel ◽  
R. Huster
Keyword(s):  
Activated Sludge ◽  
Surface Waters ◽  
Waste Water Treatment ◽  
High Capacity ◽  
Biomass Concentration ◽  
Volume Index ◽  
Trickling Filter ◽  
Limit Values ◽  
Industrial Plants ◽  
Volume Load

In many cases, it will be advisable to enhance operational safety and increase degradation performance of existing activated sludge plants by inserting a high-capacity trickling filter with plastic media. Easily degradable carbohydrates are largely decomposed in the trickling filter at low energy requirements. This allows the subsequent activated sludge stage to be set to reduced BOD sludge load levels which are required for efficient COD elimination, because the volume load has been reduced and a higher biomass concentration can be obtained at a lower sludge volume index. In the light of several years' pilot testing of numerous different effluents, and of knowledge derived from observations of several industrial plants in the paper sector, precise rating directives can now be given for plants of this type. It has proven advantageous to discharge the trickling filter effluent directly into the activated sludge plant without intermediate clarification. The effluent temperature, which frequently exceeds 35°C, is reduced by up to 10°C in the trickling filter. This improves the conditions prevailing in the activated sludge plant, thus permitting limit values for the discharge of effluents into surface waters to be adhered to.

scholarly journals A modified method to determine biomass concentration as COD in pure cultures and in activated sludge systems

Water SA ◽  
2002 ◽  
Vol 28 (4) ◽  
Author(s):  
Edgardo M Contreras ◽  
Nora C Bertola ◽  
Leda Giannuzzi ◽  
Noemi E Zaritzky
Keyword(s):  
Activated Sludge ◽  
Biomass Concentration ◽  
Modified Method ◽  
Pure Cultures ◽  
Activated Sludge Systems

scholarly journals Elimination of Micropollutants in Activated Sludge Reactors with a Special Focus on the Effect of Biomass Concentration

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2217 ◽  
Author(s):  
Hatoum ◽  
Potier ◽  
Roques-Carmes ◽  
Lemaitre ◽  
Hamieh ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Rate Constants ◽  
Removal Rate ◽  
Wide Spectrum ◽  
Biomass Concentration ◽  
Order Rate Constant ◽  
Special Focus ◽  
New Research ◽  
Activated Sludge Systems

This study aimed to investigate the effects of sludge retention time (SRT), hydraulic retention time (HRT), and biomass concentration (CTSS) in activated sludge systems on removal of various micropollutants (MPs), covering a wide spectrum of biodegradability. The influence of biomass concentration on the classical pseudo-first-order rate constant was verified. Results showed that the removal rate constants were affected by both the HRT and SRT. The enhancement of the SRT increased the removal of all the MPs except for two macrolide antibiotics. Application of a higher HRT also improved MP removal, as was expected from the measured removal rate constants. More interesting, our results indicated that, logically, the increase of biomass concentration (expressed as total suspended solids CTSS) from 3 to 5 gTSS L−1 significantly enhanced the removal rate of the highly and moderately degradable compounds. Conversely, a further increase to 8 gTSS L−1 produced only an unexpected moderate effect, showing that the rate was not proportional to biomass concentration, contrary to what is generally postulated. Therefore, the use of classical kinetic models is questionable, since they do not cover the entire range of boundary conditions in activated sludge systems. This work opens new research paths and suggests potential improvements to processes.

Evaluation of different shape parameters to distinguish between flocs and filaments in activated sludge images

2002 ◽  
Vol 45 (4-5) ◽  
pp. 85-91 ◽  
Author(s):  
C. Benens ◽  
R. Jenné ◽  
J.F. Van Impe
Keyword(s):  
Image Analysis ◽  
Form Factor ◽  
Activated Sludge ◽  
Waste Water Treatment ◽  
Biomass Concentration ◽  
Radius Of Gyration ◽  
Total Biomass ◽  
Shape Parameters ◽  
Sludge Waste ◽  
The Individual

The ratio of flocs to filaments in activated sludge waste water treatment plants is of extreme importance for the overall performance of the plant. In order to control this ratio the individual concentrations of flocs and filaments need to be measurable. However, no sensors which can measure these concentrations are currently available. It is proposed that by means of image analysis techniques the ratio of flocs to filaments can be determined. Combination of this ratio with the total biomass concentration results in the individual floc and filament concentration. This contribution focuses on the last step of the image analysis procedure, i.e., the classification of objects as either floc or filament. Five different shape parameters, i.e., aspect ratio, roundness, form factor, fractal dimension and reduced radius of gyration, are evaluated and compared. The results indicate that the form factor is the least suitable and the reduced radius of gyration the most suitable shape parameter to accurately classify flocs and filaments in activated sludge images.

A Combination of the Activated Sludge Process with Fixed Film Biomass to Increase the Capacity of Waste Water Treatment Plants

1984 ◽  
Vol 16 (10-11) ◽  
pp. 119-130 ◽  
Author(s):  
W Hegemann
Keyword(s):  
Waste Water ◽  
Activated Sludge ◽  
Waste Water Treatment ◽  
Biomass Concentration ◽  
Volume Index ◽  
Aeration Tank ◽  
Sludge Flocs ◽  
Fixed Film ◽  
Different Types ◽  
Porous Plastic

The volume of the activated sludge aeration tank is influenced by f/m ratio and attainable biomass concentration. Increase of biomass results in smaller tank volume. In case of overloaded plants restoration may be achieved by increase of biomass instead of construction of further tank volume. Pieces of porous plastic media filled into ordinary compressed air aeration tanks may serve as fixed film biomass support. By this method biomass concentration in the tank may be increased to two or three times normal values. At the same time the sludge volume index of the activated sludge flocs still present in the aeration tank is improved. Better sedimentation and thickening of the activated sludge occurs because smaller quantities of flocs are passed to the final clarifiers. Results of tests with different types of waste water in semi-technical scale pilot plants as well as in existing plants of different sizes are presented.

scholarly journals Modeling of Wastewater Treatment Processes in Membrane Bioreactors Compared to Conventional Activated Sludge Systems

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 285 ◽  
Author(s):  
Marta Bis ◽  
Agnieszka Montusiewicz ◽  
Adam Piotrowicz ◽  
Grzegorz Łagód
Keyword(s):  
Activated Sludge ◽  
Total Nitrogen ◽  
Biomass Concentration ◽  
Membrane Bioreactors ◽  
Effluent Quality ◽  
Conventional Activated Sludge ◽  
Treatment Processes ◽  
Significant Difference ◽  
Interesting Alternative ◽  
Activated Sludge Systems

Membrane techniques constitute an interesting alternative to conventional activated sludge systems (CAS). In membrane bioreactors (MBR), the biomass separated on membranes is retained independently of sludge sedimentation properties. As a consequence, a high biomass concentration as well as low food to microorganisms ratio can be obtained. Moreover, the development of a characteristic activated sludge population is stimulated by the specific conditions prevailing in MBRs. In the study, the operation and treatment efficiency of the MBR and CAS processes were examined and compared. Simulation was performed with the use of GPS-X software. The effluent quality obtained for the MBR system was either better or comparable to that of CAS. The most significant difference concerned the elimination of total suspended solids, which amounted to 99.8% in the MBR. Regarding nutrients, a low concentration of total phosphorus in the effluent from CAS and MBR was obtained (0.67 gP m−3 and 0.50 gP m−3, respectively). Greater differences were achieved in the case of total nitrogen. Although almost complete nitrification took place in both systems, a lower concentration of nitrate in the effluent from MBR in comparison to CAS, i.e., 11.2 gN m−3 and 14.1 gN m−3, respectively, allowed us to obtain a higher removal of total nitrogen (80.8% and 76.1%, respectively).

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