scholarly journals Elucidation of microbiological-biochemical relationships in denitrification occurring during activated sludge treatment

2001 ◽  
Author(s):  
◽  
Gavin David Drysdale
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Heterotrophic Bacteria ◽  
Process Performance ◽  
Active Fraction ◽  
Sludge Treatment ◽  
Denitrification Kinetics ◽  
Nd Systems ◽  
Kinetics Of ◽  
Physiological And Biochemical

Up until now extensive work has been done to develop kinetic models and related software that can be used successfully to simulate and design nitrification denitrification (ND) and nitrification denitrification biological excess phosphorus removal (NDBEPR) systems for efficient nitrogen removal. The denitrification kinetics of these systems have primarily been determined and attributed to the ordinary heterotrophic bacteria, now also known as the OHO fraction, otherwise not involved in biological excess phosphorus removal. However, denitrification kinetics determined for ND systems have been found to vary considerably at times when applied to NDBEPR systems because of varying OHO active fraction estimates and the unexplained occurrence of anoxic phosphorus removal and anysuccess achieved to date has been some what fortuitous. Ultimately variations in process performance and kinetics are attributable to inadequate control and lack of understanding of the ecological, physiological and biochemical activities of constituent microorganisms. There is growing concern and movement towards a better understanding of the microbial community within activated sludge in order to gain optimal control of the process.

Denitrification kinetics in biological N and P removal activated sludge systems treating municipal wastewaters

1999 ◽  
Vol 39 (6) ◽  
pp. 69-77 ◽  
Author(s):  
George A. Ekama ◽  
Mark C. Wentzel
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
P Uptake ◽  
Active Fraction ◽  
Batch Tests ◽  
P Release ◽  
Denitrification Kinetics ◽  
Nd Systems ◽  
Activated Sludge Systems ◽  
P Removal

The denitrification kinetics at 12, 20 and 30°C in nitrification denitrification biological excess phosphorus removal (NDBEPR) systems were delineated in batch tests on sludge harvested from laboratory scale M/UCT systems. In some investigations, it was found that the P release and uptake were confined exclusively (>95%) to the anaerobic and aerobic reactors respectively and the observed P removal conformed to the BEPR model of Wentzel et al. In these investigations, due to an absence of anoxic P uptake (substantiated by PHB measurements), it could be inferred that the phosphate accumulating organisms (PAOs) did not significantly contribute to the denitrification. The ordinary heterotrophic organism (OHO) and PAO groups were separated with the aid of the BEPR model of Wentzel et al. Ascribing the denitrification to the OHO group performing this process, the specific rates of denitrification associated with the utilization of slowly biodegradable COD (SBCOD) in the primary (K′2) and secondary (K′3) anoxic reactors were calculated and compared with the rates in ND systems (K2 and K3). In other investigations it was found that P release and uptake were not confined exclusively to the anaerobic and aerobic reactors respectively and the observed P removal was only about 60% of that expected from the BEPR model of Wentzel et al. In these investigations significant P uptake under anoxic conditions was observed so the PAOs may have been involved with the denitrification. However, the denitrification rates were calculated as before by attributing it exclusively to the OHOs. Widely varying K'2 rates were observed at 20°C, ranging from 0.071 to 0.335 mgNO3-N/(mgAHVSS.d). The variation in K' rate is mainly due to widely varying OHO active fraction estimates for NDBEPR systems.

Biodegradation Kinetics of 17α-Ethinylestradiol in Activated Sludge Treatment Processes

2015 ◽  
Vol 32 (7) ◽  
pp. 637-646 ◽  
Author(s):  
Mariko J. Lust ◽  
Ryan M. Ziels ◽  
Stuart E. Strand ◽  
Heidi L. Gough ◽  
H. David Stensel
Keyword(s):  
Activated Sludge ◽  
Biodegradation Kinetics ◽  
Sludge Treatment ◽  
Treatment Processes ◽  
Kinetics Of

Processes and Modelling of Nitrification Denitrification Biological Excess Phosphorus Removal Systems – A Review

1992 ◽  
Vol 25 (6) ◽  
pp. 59-82 ◽  
Author(s):  
M. C. Wentzel ◽  
G. A. Ekama ◽  
G. v. R. Marais
Keyword(s):  
Kinetic Model ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Model Development ◽  
Constant Flow ◽  
Cyclic Flow ◽  
Aerobic Nitrification ◽  
Kinetics Of ◽  
Load Conditions ◽  
Activated Sludge Systems

This paper reviews developments in modelling the kinetics of activated sludge systems: Completely aerobic nitrification, anoxic/aerobic nitrification denitrification (ND), and anaerobic/anoxic/aerobic nitrification denitrification biological excess phosphorus removal (NDBEPR) systems. The paper highlights the progress in developing a general NDBEPR activated sludge kinetic model – development of polyP organism enhanced cultures, their kinetics, simplification of the kinetics for enhanced cultures under constant flow and load conditions, extension of the simplified model to mixed culture NDBEPR systems under constant flow and load conditions, integration of the polyP organism enhanced culture kinetics with the ND kinetics to give a general NDBEPR kinetic model for cyclic flow and load which incorporates the increased specific denitrification rates observed in NDBEPR systems compared to ND systems. Areas of research that require attention to complete the development of the general NDBEPR kinetic model are identified – denitrification by polyP organisms, calibration and verification of the model for cyclic flow and load, etc.

scholarly journals An improved ASM-GDA approach to evaluate the production kinetics of loosely bound and tightly bound extracellular polymeric substances in biological phosphorus removal process

RSC Advances ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 2495-2506
Author(s):  
Hai Cui ◽  
Shan-Shan Yang ◽  
Ji-Wei Pang ◽  
Hai-Rong Mi ◽  
Chen-Chen Nuer ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Extracellular Polymeric Substances ◽  
Biological Phosphorus Removal ◽  
Activated Sludge Model ◽  
Removal Process ◽  
Degradation Processes ◽  
Production Kinetics ◽  
Biological Phosphorus ◽  
Kinetics Of

An extended activated sludge model no. 2 provides a new recognition of the contributions of both loosely- and tightly-bound EPS into phosphorus removal by incorporating their formation and degradation processes during the anaerobic–aerobic cycle.

Pilot Scale Studies on Enhanced Phosphorus Removal in a Single-Stage Activated Sludge Treatment Plant

1985 ◽  
Vol 17 (11-12) ◽  
pp. 309-310 ◽  
Author(s):  
W. Maier ◽  
P. Kainrath ◽  
Kh Krauth ◽  
R. Wagner
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Continuous Process ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Single Stage ◽  
Biological Phosphorus Removal ◽  
Sludge Treatment ◽  
Biological Phosphorus ◽  
P Removal

Enhanced biological phosphorus removal from domestic sewage was investigated in a single-stage activated sludge treatment plant with pre-denitrification operated in a continuous process. In 10 different experimental periods the influence of varying composition of the influent, varying systems of the pilot scale unit (with and without anaerobic basin), varying retention times in the different basins and varying sludge loads were investigated. Results of the experiments can be summarized as follows: the nutrient situation and especially the P/BOD5 and N/BOD5 ratios, retention time in the final clarifier, and organic sludge load plus the desired degree of nitrification have essential influence on the process and P removal efficiency. The conclusions for the pilot scale process are discussed.

Kinetics of Nitrification Denitrification Biological Excess Phosphorus Removal Systems–A Review

1991 ◽  
Vol 23 (4-6) ◽  
pp. 555-565 ◽  
Author(s):  
M. C. Wentzel ◽  
G. A. Ekama ◽  
G. v. R. Marais
Keyword(s):  
Kinetic Model ◽  
Phosphorus Removal ◽  
Systems Development ◽  
Simplified Model ◽  
Constant Flow ◽  
Cyclic Flow ◽  
Nd Systems ◽  
Kinetics Of ◽  
Load Conditions ◽  
Activated Sludge Systems

This paper reviews developments in the kinetics of biological excess phosphorus removal (BEPR) in nitrification denitrification BEPR (NDBEPR) activated sludge systems – development of polyp organism enhanced cultures, their kinetics, simplification of the kinetics for enhanced cultures under constant flow and load conditions, extention of the simplified model to mixed culture NDBEPR systems under constant flow and load conditions. The next stage will be the development of a general NDBEPR kinetic model valid for cyclic flow and load. Before such a model can be established, an important problem needs to be resolved – the kinetics of denitrification in NDBEPR systems; recent studies show that the specific denitrification rate due to slowly biodegradable COD is significantly higher in NDBEPR than in nitrification denitrification (ND) systems.

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