Anaerobic metabolism of propionate by polyphosphate-accumulating organisms in enhanced biological phosphorus removal systems

2005 ◽  
Vol 91 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Adrian Oehmen ◽  
Raymond J. Zeng ◽  
Zhiguo Yuan ◽  
Jürg Keller
Keyword(s):  
Phosphorus Removal ◽  
Anaerobic Metabolism ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

Distributed microbial state effects on competitionin enhanced biological phosphorus removal systems

2006 ◽  
Vol 54 (1) ◽  
pp. 199-207 ◽  
Author(s):  
A.J. Schuler
Keyword(s):  
Phosphorus Removal ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Storage Product ◽  
Distributed Approach ◽  
Average System ◽  
Storage Products ◽  
Profile Characteristics ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

Computer simulation of activated sludge population dynamics is a useful tool in process design, operation, and troubleshooting, but currently available programs rely on the assumption of “lumped,” or average, system characteristics in each reactor, such as microbial storage product contents. In reality, the states of individual bacteria are likely to vary due to variable residence times in reactors with completely mixed hydraulics. Earlier work by the present author introduced the MATLAB-based distributed state simulation program, Dissimulator 1.0, and demonstrated that distributed states may be particularly important in enhanced biological phosphorus removal (EBPR) systems, which rely on the cycling of bacteria through anaerobic and aerobic reactors to select for a population accumulating multiple microbial storage products. This paper explores the relationships between distributed state profiles, variable anaerobic and aerobic SRTs, and the process rates predicted by lumped and distributed approaches. Consistent with previous results, the lumped approach consistently predicted better EBPR performance than did the distributed approach. The primary reason for this was the presence of large fractions of polyphosphate accumulating organisms (PAOs) with depleted microbial storage product contents, which led to overestimation of process rates by the lumped approach. Distributed and lumped predictions were therefore most similar when microbial storage product depletion was minimal. The effects of variable anaerobic and aerobic SRTs on distributed profile characteristics and process rates are presented. This work demonstrated that lumped assumptions may overestimate EBPR performance, and the degree of this error is a function of the distributed state profile characteristics such as the degree to which fractions of the biomass contain depleted microbial storage product contents.

Uncertainty and variability in enhanced biological phosphorus removal (EBPR) stoichiometry: consequences for process modelling and optimization

2010 ◽  
Vol 61 (7) ◽  
pp. 1793-1800 ◽  
Author(s):  
Dwight Houweling ◽  
Yves Comeau ◽  
Imre Takács ◽  
Peter Dold
Keyword(s):  
Phosphorus Removal ◽  
Volatile Fatty Acids ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Feed Composition ◽  
P Limitation ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus ◽  
P Removal

The overall potential for enhanced biological phosphorus removal (EBPR) in the activated sludge process is constrained by the availability of volatile fatty acids (VFAs). The efficiency with which polyphosphate accumulating organisms (PAOs) use these VFAs for P-removal, however, is determined by the stoichiometric ratios governing their anaerobic and aerobic metabolism. While changes in anaerobic stoichiometry due to environmental conditions do affect EBPR performance to a certain degree, model-based analyses indicate that variability in aerobic stoichiometry has the greatest impact. Long-term deterioration in EBPR performance in an experimental SBR system undergoing P-limitation can be predicted as the consequence of competition between PAOs and GAOs. However, the observed rapid decrease in P-release after the change in feed composition is not consistent with a gradual shift in population.

Presence of Rhodocyclus in a full-scale wastewater treatment plant and their participation in enhanced biological phosphorus removal

2002 ◽  
Vol 46 (1-2) ◽  
pp. 123-128 ◽  
Author(s):  
J.L. Zilles ◽  
C.-H. Hung ◽  
D.R. Noguera
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Fluorescent In Situ Hybridization ◽  
Wastewater Treatment Plants ◽  
Full Scale ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

The objective of this research was to assess the relevance of organisms related to Rhodocyclus in enhanced biological phosphorus removal in full-scale wastewater treatment plants. The presence of these organisms in full-scale plants was first confirmed by fluorescent in situ hybridization. To address which organisms were involved in phosphorus removal, a method was developed which selected polyphosphate-accumulating organisms from activated sludge samples by DAPI staining and flow cytometry. Sorted samples were characterized using fluorescent in situ hybridization. The results of these analyses confirmed the presence of organisms related to Rhodocyclus in full-scale wastewater treatment plants and supported the involvement of these organisms in enhanced biological phosphorus removal. However, a significant fraction of the polyphosphate-accumulating organisms were not related to Rhodocyclus.

The effect of GAOs (glycogen accumulating organisms) on anaerobic carbon requirements in full-scale Australian EBPR (enhanced biological phosphorus removal) plants

2003 ◽  
Vol 47 (11) ◽  
pp. 37-43 ◽  
Author(s):  
A.M. Saunders ◽  
A. Oehmen ◽  
L.L. Blackall ◽  
Z. Yuan ◽  
J. Keller
Keyword(s):  
Phosphorus Removal ◽  
In Situ Hybridisation ◽  
Full Scale ◽  
Fluorescence In Situ Hybridisation ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Accumulibacter Phosphatis ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

Glycogen-accumulating organisms (GAOs) were present in six full-scale plants investigated and in all but one made a significant contribution to the amount of volatile fatty acid (VFA) taken up anaerobically. While most plants surveyed contain GAOs, it was demonstrated that it is possible for a full-scale plant to operate with an insignificant GAO population.“Candidatus Accumulibacter phosphatis”were the significant polyphosphate-accumulating organisms (PAOs) in all plants surveyed. “Candidatus Competibacter phosphatis” were found in all plants along with other possible GAOs that were observed but not identified. A significant GAO population will increase the carbon requirements by removing VFA that could otherwise have been used by PAOs. Process optimization minimizing GAOs in full-scale plants would lead to a more efficient use of VFA. Enhanced biological phosphorus removal (EBPR), fluorescence in situ hybridisation (FISH), glycogen accumulating organism (GAO); polyphosphate accumulating organism (PAO);

scholarly journals Identity and Ecophysiology of Uncultured Actinobacterial Polyphosphate-Accumulating Organisms in Full-Scale Enhanced Biological Phosphorus Removal Plants

2005 ◽  
Vol 71 (7) ◽  
pp. 4076-4085 ◽  
Author(s):  
Yunhong Kong ◽  
Jeppe Lund Nielsen ◽  
Per Halkjær Nielsen
Keyword(s):  
Phosphorus Removal ◽  
Treatment Plant ◽  
Full Scale ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Fish Analysis ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

ABSTRACT Microautoradiography combined with fluorescence in situ hybridization (MAR-FISH) was used to screen for potential polyphosphate-accumulating organisms (PAO) in a full-scale enhanced biological phosphorus removal (EBPR) plant. The results showed that, in addition to uncultured Rhodocyclus-related PAO, two morphotypes hybridizing with gene probes for the gram-positive Actinobacteria were also actively involved in uptake of orthophosphate (Pi). Clone library analysis and further investigations by MAR-FISH using two new oligonucleotide probes revealed that both morphotypes, cocci in clusters of tetrads and short rods in clumps, were relatively closely related to the genus Tetrasphaera within the family Intrasporangiaceae of the Actinobacteria (93 to 98% similarity in their 16S rRNA genes). FISH analysis of the community biomass in the treatment plant investigated showed that the short rods (targeted by probe Actino-658) were the most abundant (12% of all Bacteria hybridizing with general bacterial probes), while the cocci in tetrads (targeted by probe Actino-221) made up 7%. Both morphotypes took up Pi aerobically only if, in a previous anaerobic phase, they had taken up organic matter from wastewater or a mixture of amino acids. They could not take up short-chain fatty acids (e.g., acetate), glucose, or ethanol under anaerobic or aerobic conditions. The storage compound produced during the anaerobic period was not polyhydroxyalkanoates, as for Rhodocyclus-related PAO, and its identity is still unknown. Growth and uptake of Pi took place in the presence of oxygen and nitrate but not nitrite, indicating a lack of denitrifying ability. A survey of the occurrence of these actinobacterial PAO in 10 full-scale EBPR plants revealed that both morphotypes were widely present, and in several plants more abundant than the Rhodocyclus-related PAO, thus playing a very important role in the EBPR process.

Effect of pH reduction on polyphosphate- and glycogen-accumulating organisms in enhanced biological phosphorus removal processes

2010 ◽  
Vol 62 (6) ◽  
pp. 1432-1439 ◽  
Author(s):  
Toshikazu Fukushima ◽  
Motoharu Onuki ◽  
Hiroyasu Satoh ◽  
Takashi Mino
Keyword(s):  
Phosphorus Removal ◽  
Quantitative Polymerase Chain Reaction ◽  
Time Lag ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Delayed Effect ◽  
Effect Of Ph ◽  
Ph Reduction ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

We investigated the effect of pH reduction on polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in the enhanced biological phosphorus removal (EBPR) process. Three laboratory-scale EBPR reactors were used. Initially, the reactors were operated at pH 7.9 ± 0.1 and 6.5 ± 0.1, and after 27 days, the pH was lowered to 6.5 ± 0.1 and 6.0 ± 0.1, respectively. PAOs and GAOs were monitored using real-time quantitative polymerase chain reaction and/or fluorescent in situ hybridization. Phosphorus removal performance was also monitored. During the start-up period, high EBPR activity and increases in Candidatus ‘Accumulibacter phosphatis’ (Accumulibacter) and Candidatus ‘Competibacter phosphatis’ (Competibacter) were observed. In all runs, Accumulibacter and Competibacter were the dominant PAO and GAO, respectively. Accumulibacter began to decline 10–18 days after lowering the pH to 6.5 ± 0.1. After lowering the pH to 6.0 ± 0.1, the Accumulibacter population decreased immediately. Contrastingly, an obvious adverse effect of pH reduction on Competibacter was not observed. In all runs, EBPR activity began to deteriorate 6–12 days after Accumulibacter decline began. Thus, our results show that pH reduction had an immediate or delayed effect on Accumulibacter decline. Moreover, the time lag between the start of Accumulibacter decline and that of EBPR deterioration implies that EBPR deterioration by pH reduction went through unknown process.

Competition between polyphosphate- and glycogen-accumulating organisms in biological phosphorus removal systems – effect of temperature

2002 ◽  
Vol 46 (1-2) ◽  
pp. 191-194 ◽  
Author(s):  
L.-M. Whang ◽  
J.K. Park
Keyword(s):  
High Temperatures ◽  
Uptake Rate ◽  
Phosphorus Removal ◽  
Effect Of Temperature ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Batch Studies ◽  
Acetate Uptake ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

This study demonstrated that temperature is an important factor in determining the outcome of competition between polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating non-poly-P organisms (GAOs) and the resultant stability of enhanced biological phosphorus removal (EBPR) systems. At 20°C and a 10-day sludge age, PAOs were dominant in the anaerobic/aerobic (A/O) SBR, however, at 30°C and a 10-day sludge age, GAOs were dominant in the A/O SBR. For kinetic batch studies, the anaerobic specific acetate uptake rate of GAO-dominated sludge (1.34 × 10−3 mg C/mg VSS·minute) was higher than the rate of PAO-dominated sludge (0.89 × 10−3 mg C/mg VSS·minute) at 30°C, leading to the eventual failure of EBPR processes at high temperatures.

Could nitrite/free nitrous acid favour GAOs over PAOs in enhanced biological phosphorus removal systems?

2011 ◽  
Vol 63 (2) ◽  
pp. 345-351 ◽  
Author(s):  
M. Pijuan ◽  
L. Ye ◽  
Z. Yuan
Keyword(s):  
Phosphorus Removal ◽  
Nitrous Acid ◽  
Wastewater Treatment Plants ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Inhibitory Effects ◽  
Nitrogen Gas ◽  
Free Nitrous Acid ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus

Enhanced biological phosphorus removal (EBPR) normally occurs together with nitrogen removal in wastewater treatment plants (WWTPs). In recent years, efforts have been devoted to remove nitrogen via the nitrite pathway (oxidation of ammonia to nitrite and reduction of nitrite to nitrogen gas without going through nitrate), reducing the requirement for carbon and oxygen in the plant. However nitrite and free nitrous acid (FNA), the protonated species of nitrite, have been shown to cause EBPR deterioration under certain concentrations. This study provides a direct comparison between the different levels of FNA inhibition in the aerobic processes of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) by reviewing the studies published in this area. Also, new data is presented assessing the FNA effect on the anaerobic metabolism of these two groups of bacteria. Overall, FNA has shown inhibitory effects on most of the processes involved in the metabolism of PAOs and GAOs. However, the inhibition-initiation levels are different between different processes and, even more importantly between the two groups. In general, PAOs appear to be more affected than GAOs at the same level of FNA, thus giving GAOs competitive advantage over PAOs in EBPR systems when nitrite is present.

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