The effect of pH on the competition between polyphosphate-accumulating organisms and glycogen-accumulating organisms

Carvalheira, Mónica; Oehmen, Adrian; Carvalho, Gilda; Eusébio, Mário; Reis, Maria A. M.

doi:10.1016/j.watres.2005.06.031

Cited by 171 publications

(89 citation statements)

References 32 publications

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“…Acetate can be anaerobically taken up by both R-PAOs and GB-GAOs at similar rates [30,33]. Other physiological similarities between these two groups also indicate an overlay of ecological niches, but Accumulibacter and Competibacter coexist very often for other unresolved factors in full-scale plants with efficient EBPR [7,50].…”

Section: Wastewater Compositionmentioning

confidence: 97%

“…The performance of EBPR systems depends on the competition of PAOs with GAOs, so it is desirable to minimise the growth of the latter in reactors [33]. Most research is carried out in lab-scale SBRs fed with a single carbon source, usually acetate or propionate [10,12,[27][28][29][30][31][32]49]. Due to the nature of these experiments conducted with highly enriched cultures, key aspects of PAO and GAO ecophysiology and their competition in full-scale systems need elucidation.…”

Section: Wastewater Compositionmentioning

confidence: 99%

“…Other physiological similarities between these two groups also indicate an overlay of ecological niches, but Accumulibacter and Competibacter coexist very often for other unresolved factors in full-scale plants with efficient EBPR [7,50]. On the other hand, there are many reports of the sudden deterioration of labscale systems fed with acetate due to the probable dominance of GB-GAOs over R-PAOs [10,30,33]. Other studies showed that Competibacter takes up propionate less efficiently than Accumulibacter and this substrate can be used to successfully outcompete GB-GAOs [31,33].…”

Section: Wastewater Compositionmentioning

confidence: 99%

“…Numerous studies by Flowers et al [52], He et al [15,53] and Oehmen et al [30,31,33] have found that lower COD/P ratios of 10-15 should be used for successful enrichment (>80% of all bacteria) of Accumulibacter in lab-scale reactors. However, there are some contradicting studies which indicate that low C/P ratios are not sufficient for outcompeting GAOs nor achieving low phosphorus effluent even in lab-scale optimal conditions.…”

Section: C/p Ratio In Influentmentioning

confidence: 99%

“…Most experiments have been carried out with highly enriched PAO (or GAO) cultures in lab-scale reactors fed with a single carbon source, typically acetate or propionate [11,12,[27][28][29][30][31][32][33][34]. In the current study a mixture of organic substrates was used to provide a higher diversity of substrates in the influent.…”

Section: Introductionmentioning

confidence: 99%

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From macro to lab-scale: Changes in bacterial community led to deterioration of EBPR in lab reactor

et al. 2013

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A laboratory scale sequencing batch reactor (SBR), fed with synthetic wastewater containing a mixture of organic compounds, was operated for nearly six months. Despite maintaining the same operational conditions, a deterioration of enhanced biological phosphorus removal (EBPR) occurred after 40 days of SBR operation. The Prel/Cupt ratio decreased from 0.28 to 0.06 P-mol C-mol−1, and C requirements increased from 11 to 32 mg C h−1 g−1 of mixed liquor suspended solids. A FISH analysis showed that the percentage of Accumulibacter in an overall community of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) dropped from 93% to 13%. An increase in abundance of Gammaproteobacteria (from 2.6% to 22%) and Alphaproteobacteria (from 1.8% to 10%) was observed. The number of Competibacter increased from 0.5% to nearly 9%. Clusters 1 and 2 of Defluviicoccus-related GAOs, not detected before deterioration, constituted 35% and 27% of Alphaproteobacteria, respectively. We concluded that lab-scale experiments should not be extended implicitly to full-scale EBPR systems because some bacterial groups are detected mainlyin lab-scale reactors. Well-defined, lab-scale operational conditions reduce the number of ecological niches available to bacteria.

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Section: Wastewater Compositionmentioning

confidence: 97%

Section: Wastewater Compositionmentioning

confidence: 99%

Section: Wastewater Compositionmentioning

confidence: 99%

Section: C/p Ratio In Influentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

From macro to lab-scale: Changes in bacterial community led to deterioration of EBPR in lab reactor

et al. 2013

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Inducing mechanism of biological phosphorus removal driven by the aerobic/extended‐idle regime

Wang

Yang

et al. 2012

Biotech & Bioengineering

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Recently, it was found that excess phosphorus (Pi) removal could be achieved in activated sludge with an aerobic/extended-idle (AEI) process. In this study, batch tests were performed to further reveal the inducing mechanism of Pi removal involved in the AEI process. Unlike the classical anaerobic/aerobic process where an anaerobic Pi release along with a significant polyhydroxyalkanoate (PHA) accumulation drives polyphosphate (poly-P) accumulating organisms (PAOs) to over-store Pi as poly-P, an idle Pi release accompanied by a low-idle PHA production, which is usually considered to be detrimental for biological Pi removal, was observed to induce some cells to effectively uptake Pi in excess of metabolic requirement in the AEI process. With the increase of idle Pi release, Pi removal efficiency linearly increased. The results also showed that a long idle period with a low level of intracellular glycogen could significantly increase Pi release contents, thus remarkably enhancing Pi removal performances. Fluorescence in situ hybridization analysis further revealed that activated sludge in the AEI process contained 37.6% of Accumulibacter (PAOs) and 28.2% of Competibacter and Defluviicoccus-related organisms (glycogen accumulating organisms). This study revealed an actually existent, yet previously unrecognized, inducing mechanism of poly-P accumulation, and this mechanism behind the AEI regime may provide a scientific basis for the development of an alternative strategy for Pi removal from wastewaters.

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Evaluation of the feasibility of alcohols serving as external carbon sources for biological phosphorus removal induced by the oxic/extended‐idle regime

Wang

Zheng

et al. 2012

Biotech & Bioengineering

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Recently, a novel operational regime (i.e., the oxic/extended-idle [OEI] regime) has been reported to successfully achieve enhanced biological phosphorus removal (EBPR) when employing glucose and volatile fatty acids as the sole substrate. In the OEI regime, polyphosphate accumulating organisms (PAOs) could get a selective advantage over other populations during the extended-idle period where polyphosphate released but polyhydroxyalkanoates and glycogen transformations were negligible/low, thus energy requirements for maintenance purposes in the period could be covered by polyphosphate release. This study further evaluated the feasibility of alcohols as external carbon sources for EBPR induced by the OEI regime, as the available substrate in the raw wastewater is often deficient. First, phosphorus removal in the OEI process was compared, respectively, with methanol and ethanol as the sole substrate. The results showed that the ethanol-reactor achieved 90.8 ± 2.3% of phosphorus removal, which was approximate twofold than the methanol-reactor. Further studies displayed that the cells in the ethanol-reactor contained more PAOs, and had higher activities of exopolyphosphatase and polyphosphate kinase than those in the methanol-reactor. Also, the aerobic transformations of polyhydroxyalkanoates and glycogen in the ethanol-reactor were, respectively, higher and lower than those in the methanol-reactor, which were consistent with the reactors performances. Then, the feasibility of using ethanol as external substrate to enhance EBPR in the OEI process was confirmed for a municipal wastewater. Finally, EBPR performance and metabolic transformation values between the OEI and the anaerobic/oxic (A/O) regimes with ethanol as the sole substrate were compared. The results showed that EBPR in the ethanol-OEI reactor was higher than that in the ethanol-A/O reactor. All the above results proved that ethanol was a favorable external substrate to the OEI regime for EBPR enhancement.

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The effect of pH on the competition between polyphosphate-accumulating organisms and glycogen-accumulating organisms

Cited by 171 publications

References 32 publications

From macro to lab-scale: Changes in bacterial community led to deterioration of EBPR in lab reactor

From macro to lab-scale: Changes in bacterial community led to deterioration of EBPR in lab reactor

Inducing mechanism of biological phosphorus removal driven by the aerobic/extended‐idle regime

Evaluation of the feasibility of alcohols serving as external carbon sources for biological phosphorus removal induced by the oxic/extended‐idle regime

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