Which are the polyphosphate accumulating organisms in full-scale activated sludge enhanced biological phosphate removal systems in Australia?

Abstract

Aims: To see if the compositions of the microbial communities in full scale enhanced biological phosphorus removal activated sludge systems were the same as those from laboratory scale sequencing batch reactors fed a synthetic sewage. Methods: Biomass samples taken from nine full scale enhanced biological phosphate removal (EBPR) activated sludge plants in the eastern states of Australia were analysed for their populations of polyphosphate (polyP)‐accumulating organisms (PAO) using semi‐quantitative fluorescence in situ hybridization (FISH) in combination with DAPI (4′‐6‐diamidino‐2‐phenylindole) staining for polyP. Results: Very few betaproteobacterial Rhodocyclus related organisms could be detected by FISH in most of the plants examined, and even where present, not all these cells even within a single cluster, stained positively for polyP with DAPI. In some plants in samples from aerobic reactors the Actinobacteria dominated populations containing polyP. Conclusions: The PAO populations in full‐scale EBPR systems often differ to those seen in laboratory scale reactors fed artificial sewage, and Rhodocyclus related organisms, dominating these latter communities may not be as important in full‐scale systems. Instead Actinobacteria may be the major PAO. Significance and Impact of the Study: These findings illustrate how little is still known about the microbial ecology of EBPR processes and that more emphasis should now be placed on analysis of full‐scale plants if microbiological methods are to be applied to monitoring their performances.

Filamentous Bacterium Eikelboom Type 0092 in Activated Sludge Plants in Australia Is a Member of the Phylum Chloroflexi

“…Several reports have suggested that the Chloroflexi and type 0092 are frequent members of EBPR communities (7,8,24), although whether they play any role in phosphate removal in these communities is uncertain. None in samples taken at the end of the aerobic stage stained positively for polyP in our study.…”

Abundance of Candidatus 'Accumulibacter phosphatis' in Enhanced Biological Phosphorus Removal Activated Sludge Acclimatized with Different Carbon Sources

“…In a laboratory-scale EBPR reactor fed propionate, Candidatus 'Accumulibacter phosphatis' occupied over 30% of the eubacterial population 18) . In addition, Candidatus 'Accumulibacter phosphatis' has also been found (4-18% of eubacteria) in full scale plants treating domestic sewage 24) and accumulated polyphosphate 5) . It is now regarded as one of the key PAOs species in EBPR processes 19) .…”

Quantification of Rhodocyclus-Related and Actinobacterial Polyphosphate-Accumulating Organisms in an Enhanced Biological Phosphorus Removal Process Using Quenching Probe PCR

“…Moreover, others speculated that Rhodocyclus-related PAOs (RPAOs) are an important PAO group in some EBPR processes 7,8) . On the other hand, Actinobacteria have also been found to be PAOs using clone libraries 14) , quinone profiling 21) , and FISH 3,28) . Liu et al indicated that some members of Actinobacteria composed one of the predominant groups of PAOs in a laboratory-scale EBPR process as determined by FISH with an Actino_1011 probe and 4',6'-diamidino-2-phenyl indol dihydrochloride staining 14) .…”