Modeling External Carbon Addition in Biological Nutrient Removal Processes with an Extension of the International Water Association Activated Sludge Model

2012 ◽  
Vol 84 (8) ◽  
pp. 646-655 ◽  
Author(s):  
M Swinarski ◽  
J Makinia ◽  
H.D Stensel ◽  
K Czerwionka ◽  
J Drewnowski
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Biological Nutrient Removal ◽  
Carbon Addition ◽  
Activated Sludge Model ◽  
Water Association ◽  
International Water ◽  
Removal Processes

Activated sludge modelling in practice: an international survey

2009 ◽  
Vol 60 (8) ◽  
pp. 1943-1951 ◽  
Author(s):  
H. Hauduc ◽  
S. Gillot ◽  
L. Rieger ◽  
T. Ohtsuki ◽  
A. Shaw ◽  
...  
Keyword(s):  
Knowledge Transfer ◽  
Activated Sludge ◽  
Task Group ◽  
International Survey ◽  
Activated Sludge Model ◽  
Practice Task ◽  
The World ◽  
Water Association ◽  
International Water ◽  
Activated Sludge Models

The Good Modelling Practice Task Group (GMP-TG) of the International Water Association (IWA) is developing guidelines for the use of Activated Sludge Models (ASM). As part of this work the group created and sent out a questionnaire to current and potential activated sludge model users in 2007. The objectives of the questionnaire were (i) to better define the profile of ASM users, (ii) to identify the tools and procedures that are actually used and (iii) to highlight the main limitations while building and using ASM-type models. Ninety-six answers were received from all over the world, from several types of organisation. The results were analysed to identify the modellers' perceptions of models depending on their profile. The results also highlighted the main topics of interest for improving modelling procedures which are standardisation of the available modelling guidelines and better experience and knowledge transfer.

The effect of chemical bulking control on biological nutrient removal in a full scale activated sludge plant

1996 ◽  
Vol 34 (3-4) ◽  
pp. 275-282 ◽  
Author(s):  
G. B. Saayman ◽  
C. F. Schutte ◽  
J. van Leeuwen
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Full Scale ◽  
City Council ◽  
Phosphate Removal ◽  
Biological Nutrient Removal ◽  
Removal Processes ◽  
The City

The use of chemicals for sludge bulking control has a direct effect on the biological nutrient removal processes in activated sludge systems designed for this purpose. Chlorine has been used on full scale but information on the use of ozone and hydrogen peroxide is limited to pilot scale tests. The objective of this study was to investigate the effects of chlorine, ozone and hydrogen peroxide on nutrient removal processes when used on a continuous basis for bulking control in a full scale biological nutrient removal activated sludge plant. The full scale studies were conducted over a period of 39 months at the Daspoort sewage works of the City Council of Pretoria. The results indicate that at low dosages the oxidants have limited effects on the nutrient removal processes but at higher levels chlorine had a detrimental effect resulting in the phosphate limit of 1 mg P.1−1 being exceeded. It is concluded that chlorine is the most effective of the three oxidants for bulking control, but that it should be used with caution in order not to upset the biological phosphate removal processes. Ozone at low levels had a small but consistent positive effect on bulking control as well as on nutrient removal. The effects of hydrogen peroxide were very small except at high dosages.

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.

Comparison of phosphorus removal characteristics between various biological nutrient removal processes

1997 ◽  
Vol 36 (12) ◽  
pp. 61-68 ◽  
Author(s):  
Eun Lee Sang ◽  
Soo Kim Kwang ◽  
Hwan Ahn Jae ◽  
Whoe Kim Chang
Keyword(s):  
Adverse Effect ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Phosphorus Release ◽  
Biological Nutrient Removal ◽  
Phosphorus Concentration ◽  
Bench Scale ◽  
Removal Processes

Bench scale experiments were carried out with four biological nutrient removal(BNR) units, A/O, A2/O, Phostrip and P/L units, to investigate the behavior of phosphorus in the system and to compare the characteristics of phosphorus removal in four experimental BNR units. The influent COD/T-P ratio was varied from 22 to 64 by changing COD concentration while maintaining phosphorus concentration constant. In general sidestream BNR units such as Phostrip and P/L units outperformed mainstream BNR units such as A/O and A2/O units in terms of phosphorus removal. While phosphorus release and uptake in A/O and A2/O units became less significant at low influent COD/T-P, the phosphorus release in A2/O unit was further influenced by nitrate in return sludge and thus A2/O unit required even higher influent COD/T-P ratio for luxury uptake of phosphorus. The luxury uptake of phosphorus in Phostrip and P/L units were not affected by influent COD/T-P ratio and the adverse effect of nitrate in return sludge on anaerobic phosphorus release in P/L process was not significant due to the sludge blanket in P-stripper.

Difficulties and developments in biological nutrient removal technology and modelling

1999 ◽  
Vol 39 (6) ◽  
pp. 1-11 ◽  
Author(s):  
George A. Ekama ◽  
Mark C. Wentzel
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Filamentous Bulking ◽  
Recent Developments ◽  
Removal Technology ◽  
Hydrolysis Of ◽  
Activated Sludge Systems ◽  
P Removal

Filamentous bulking and the long sludge age required for nitrification are two important factors that limit the wastewater treatment capacity of biological nutrient removal (BNR) activated sludge systems. A growing body of observations from full-scale plants indicate support for the hypothesis that a significant stimulus for filamentous bulking in BNR systems in alternating anoxic-aerobic conditions with the presence of oxidized nitrogen at the transition from anoxic to aerobic. In the DEPHANOX system, nitrification takes place externally allowing sludge age and filamentous bulking to be reduced and increases treatment capacity. Anoxic P uptake is exploited in this system but it appears that this form of biological excess P removal (BEPR) is significantly reduced compared with aerobic P uptake in conventional BNR systems. Developments in the understanding of the BEPR processes of (i) phosphate accumulating organism (PAO) denitrification and anoxic P uptake, (ii) fermentation of influent readily biodegradable (RB)COD and (iii) anaerobic hydrolysis of slowly biodegradable (SB)COD are evaluated in relation to the IAWQ Activated Sludge Model (ASM) No.2. Recent developments in BEPR research do not yet allow a significant improvement to be made to ASM No. 2 that will increase its predictive power and reliability and therefore it remains essentially as a framework to guide further research.

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