Contribution of Pseudomonas spp. to phosphorus uptake in the anoxic zone of an anaerobic-anoxic-aerobic continuous activated sludge system

2001 ◽  
Vol 43 (1) ◽  
pp. 139-146 ◽  
Author(s):  
B. W. Atkinson ◽  
D. D. Mudaly ◽  
F. Bux
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Phosphate Uptake ◽  
Phosphorus Uptake ◽  
Bulk Liquid ◽  
Anoxic Zone ◽  
Mixed Liquor ◽  
Pseudomonas Spp ◽  
Activated Sludge System ◽  
Polyphosphate Accumulation

A continuously operated laboratory-scale (32 L) nitrification denitrification biological excess phosphorus removal (NDBEPR) activated sludge system (modeled on the 3-stage Phoredox configuration) was maintained for 140 d. The transition from a non-biological excess phosphorus removal (BEPR) sludge to one exhibiting a strong BEPR mechanism was monitored. Mixed liquor seed inoculum was obtained from a full-scale single aerobic activated sludge installation and subjected to conditions conducive to BEPR, i.e. increasing influent acetate (HAc) concentrations. At a sludge age of 10 d with 100% HAc feed, the system was capable of removing a maximum of ca. 40 mgPO4–P/L from the bulk liquid; P/VSS of ca. 0.27 (mgP/mgVSS); and VSS/TSS of 0.53 (mgVSS/mgTSS) in the aerobic zone was attained. Although typical BEPR phosphorus transformation patterns were routinely observed, i.e. anaerobic phosphate release and aerobic phosphate uptake, phosphate uptake in the anoxic zone was also recorded indicating the presence of denitrifying phosphorus accumulating organisms (DPAOs) in the sludge community. The microbial community was screened (using both isolation and direct methods of analysis) for the presence of Pseudomonas spp. as this genus is known to perform both polyphosphate accumulation and denitrification processes. Isolation of anoxic mixed liquor bacteria on solid media and identification using the API 20NE system resulted in the total dominance of the Pseudomonads (>50%). However, direct fluorescent in situ hybridizations (FISH) revealed that Pseudomonas spp. only constituted ca. 3% of the total bacterial community indicating that other bacterial genera are contributing to simultaneous polyphosphate accumulation and denitrification processes in the anoxic zones of NDBEPR systems.

Start-Up of A2/O Humic Activated Sludge Systemphosphorus Removal Efficiency Analysis

2010 ◽  
Vol 113-116 ◽  
pp. 2201-2207 ◽  
Author(s):  
Jun Yin ◽  
Lei Wu ◽  
Ke Zhao ◽  
Yu Juan Yu
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Phosphorus Removal ◽  
Removal Rate ◽  
Phosphorus Uptake ◽  
Phosphorus Release ◽  
Activated Sludge System ◽  
Start Up ◽  
Article Analysis ◽  
Sludge Activity

In this article, analysis the start-up of A2/O humic activated sludge system phosphorus removal efficiency and the characteristics of anaerobic phosphorus release, aerobic phosphorus uptake, sludge activity and their change in the Series Technologies process. The results show that A2/O humic activated sludge system phosphorus removal rate stabilized at 90.7% ~ 97.6%. Sludge activity except for anoxic zone 2 increased, along the process showed a gradual decrease trend.

Design Considerations for Nutrient Removal Activated Sludge Plants

1991 ◽  
Vol 23 (4-6) ◽  
pp. 781-790 ◽  
Author(s):  
A. R. Pitman
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Full Scale ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Anoxic Zone ◽  
Mixed Liquor ◽  
Design Considerations ◽  
Biological Phosphorus

Based on more than 10 years' experience with biological nutrient removal in Johannesburg, this paper highlights aspects which should be borne in mind in the design of such processes. Feed sewage quality and the question of treating raw or settled sewage are considered. More importantly, methods of rendering the feed more suitable for biological phosphorus removal are detailed. As nitrate feedback to the anaerobic zone can often mitigate against good phosphorus removal, methods of obviating this are covered. In this respect the need for, and placement of a second anoxic zone are discussed. Process type and configuration are covered as well as zone retention periods and the split of process volume into unaerated and aerated fractions. Aeration systems and the tailoring of aeration to process needs are also discussed. Two problems that have been experienced in many full-scale plants are bulking sludges and prolific growths of nuisance scums. Methods of minimising these problems are discussed. Finally, mixed liquor and return sludge recycles; aspects to be borne in mind in the design of final clarifiers and the provision of standby chemical addition are discussed.

Biochemical Aspects of Enhanced Biological Phosphorus Removal from Wastewater

1985 ◽  
Vol 17 (11-12) ◽  
pp. 23-41 ◽  
Author(s):  
M. C. Hascoet ◽  
M. Florentz ◽  
P. Granger
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Phosphorus Uptake ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
The Past ◽  
Nitrate Addition ◽  
The Subject ◽  
Biological Phosphorus ◽  
Microbiological Analyses

Enhanced biological phosphorus removal from wastewater by means of microorganisms found in activated sludge has for the past few years been the subject of much research and it is now commonly recognized that an activated sludge system must include alternating anaerobic-aerobic periods. The present article covers biochemical aspects of this phenomenon using a phosphorus removing biomass obtained in a laboratory-scale pilot with alternating phases and a synthetic substrate feed. The percentage of phosphorus obtained in the pilot sludge was four times greater than that of a conventional sludge plant. By exposing the same biomass to different conditions and using 31P Nuclear Magnetic Resonance, we were able to accurately pin-point the various forms of phosphorus found within cells and follow their development during the course of alternating phases. The following results were obtained:the transformation of phosphorus in its inorganic to polyphosphate form depends on the medium's level of oxygenation,the presence of nitrates disturbs the anaerobic period but does not affect phosphorus uptake in the aerated period.Continuous nitrate addition alters biomass behaviour in the anaerobic phase, which loses the capacity to release phosphorus,copper at a concentration of over 1 mg Cu2+/1 inhibits phosphorus uptake in the aerated phase. Various microbiological analyses made on the pilot biomass isolated conventional bacteria found in activated sludge.

Full-Scale Cyclic Activated Sludge System Phosphorus Removal

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2253-2256 ◽  
Author(s):  
M. C. Goronszy
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Full Scale ◽  
Biological Phosphorus Removal ◽  
Fill Ratio ◽  
Variable Volume ◽  
Activated Sludge System ◽  
Sludge Bulking ◽  
Volume Mode ◽  
Biological Phosphorus

The performance of three full-scale cyclic activated sludge facilities, operated for biological phosphorus removal is demonstrated. The facilities are operated without formal mixed anoxic or anaerobic sequences in a variable volume mode. The system is independent of fill-ratio operation for filamentous sludge bulking control.

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