scholarly journals Performance of enhanced biological phosphorus removal and population dynamics of phosphorus accumulating organisms in sludge-shifting sequencing batch reactors

2018 ◽  
Vol 78 (4) ◽  
pp. 886-895 ◽  
Author(s):  
Yang Pan ◽  
Wenquan Ruan ◽  
Yong Huang ◽  
Qianqian Chen ◽  
Hengfeng Miao ◽  
...  

Abstract The sludge-shifting sequencing batch reactor (SBR) is an enhanced biological phosphorus removal (EBPR) process for wastewater treatment. In this study, the enrichment of phosphorus accumulating organisms (PAOs) will be attempted by using different high concentration of substrates. In sludge-shifting SBR, activated sludge can be continuously shifted from the bottom of SBR to anaerobic zone/selector, which contains high concentration of substrates, through an orderly reflux between the paralleled SBRs. Denaturing gradient gel electrophoresis (DGGE) methods were used to monitor microbial diversity in sludge. Fluorescence in situ hybridization (FISH) was used to determine the microbial population profile and distribution map under different sludge shifting volumes. The synthesis of intracellular polymers in this process was also analyzed. Phosphorus removal efficiency as high as 96% ± 1.3% was achieved under a sludge shifting ratio of 30%. Synthetic efficiencies of polyhydroxybutyrate (PHB) by PAOs were improved at high sludge shifting ratios. FISH results demonstrated that the population of PAOs in the process increased under properly sludge shifting ratio and it significantly improved phosphorus removal efficiency. Sequencing results indicated that determined sequences (11 OTUs) belonged to Proteobacterium, Actinobacteria and Firmicutes, Pseudomonas kuykendallii, which played an important role in the process of P removal.

2001 ◽  
Vol 43 (3) ◽  
pp. 183-189 ◽  
Author(s):  
C. Y. Dassanayake ◽  
R. L. Irvine

A control strategy was developed for enhanced biological phosphorus removal (EBPR) in a Sequencing Batch Reactor (SBR). Unlike past research that focused on maximizing polyhdroxyalkanoate (PHA) formation during the anaerobic period, this study investigated some of the factors that govern aerobic PHA dynamics and its efficient regulation during phosphate (P) uptake. Influent COD, influent P, and the time for aeration were critical factors that governed PHA use and P uptake during aerated react. Unnecessary PHA oxidation (i.e., in the absence of extracellular P) occurred if the time for aerated react exceeded the time required for P uptake. By adjusting the aeration time to that required for P uptake, residual PHA was sustained in the SBR and excess phosphate uptake reaction potential (PRP) was generated for use during transient influent excursions in P. Unlike space oriented systems, the time for react is simply adjusted in the SBR. Because residual PHA is easily maintained once achieved, high influent COD events can be harnessed to increase or sustain excess PRP for management of expected variations in influent P.


2002 ◽  
Vol 46 (1-2) ◽  
pp. 195-198 ◽  
Author(s):  
A.J. Schuler ◽  
M. Onuki ◽  
H. Satoh ◽  
T. Mino

A novel approach to the identification of microorganisms that accumulate high density microbial storage products based on density separation, denaturing gradient gel electrophoresis (DGGE), and DNA sequencing was developed and applied to bench and pilot scale enhanced biological phosphorus removal (EBPR) systems. Polyphosphate (PP), glycogen, and polyhydroxyalkanoates (PHAs), are all of higher density than a typical bacterial cell. PP-accumulating organisms (PAOs), the organisms responsible for EBPR, accumulate all three of these storage products. Density separation in a homogenous solution of Percoll produced a high-density biomass fraction with a relatively high concentration of PAOs, as determined by Neisser staining. DNA was extracted from these fractions, amplified, and separated by DGGE. DGGE profiles demonstrated some bacterial strains were present at a greater concentration in the high density fractions than in low density fractions. These strains were considered PAO candidates. 5 of 12 PAO candidates from high density fractions were γ Proteobacteria and only 1 was a β Proteobacterium. 2 PAO candidates were most similar to recently identified γ Proteobacteria sequences obtained by DGGE analysis of a deteriorated benchtop EBPR system.


2002 ◽  
Vol 46 (1-2) ◽  
pp. 145-154 ◽  
Author(s):  
M. Onuki ◽  
H. Satoh ◽  
T. Mino

Enhanced biological phosphorus removal (EBPR) activated sludge was operated in a laboratory-scale sequencing batch reactor (SBR) fed with acetate as the sole carbon source. The microbial community of the sludge was analyzed using the polymerase chain reaction (PCR) – denaturing gradient gel electrophoresis (DGGE) method for about 2 months of start-up period. As a result, the number of major bands decreased during the enrichment, indicating that the microbial community structure was getting simpler. Since the phosphate removal activity was maintained at a high level, the bacteria which still remained at the end can be considered as the important bacteria playing key roles in the present EBPR sludge, maybe polyphosphate accumulating organisms (PAOs). The dominant band in the last sample on the DGGE gel was excised and the DNA recovered from it was sequenced. The sequence was closely related to one of the putative PAOs group which Crocetti et al. (2000) and Hesselmann et al. (1999) have proposed. This PAOs group is closely related to the Rhodocyclus group (b-Proteobacteria). The fluorescence in situ hybridization (FISH) method with the probe specific for this PAOs group and the DAPI staining at a phosphate-probing concentration indirectly showed that these Rhodocyclus related bacteria really accumulated polyphosphate.


1994 ◽  
Vol 29 (7) ◽  
pp. 109-117 ◽  
Author(s):  
J. S. Čech ◽  
P. Hartman ◽  
M. Macek

Population dynamics of polyphosphate-accumulating bacteria (PP bacteria) was studied in a laboratory sequencing batch reactor simulating anaerobic-oxic sludge system. The competition between PP bacteria and another microorganism (“G bacteria”) for anaerobic-oxic utilization of acetate as the sole source of organic carbon was observed. The competition was found to be seriously influenced by protozoan and metazoan grazing: Predation-resistant “G bacteria” forming large compact flocs outcompeted PP bacteria. Several breakdowns of enhanced biological phosphorus removal were observed. The first one was related to the development of an euglenid flagellate Entosiphon sulcatus and attached ciliates Vorticella microstoma and V. campanula. The second system collapse was connected with a rapid proliferation of rotifers. An alternative-prey predation was thought to be a mechanism of PP bacteria elimination.


1999 ◽  
Vol 65 (3) ◽  
pp. 1251-1258 ◽  
Author(s):  
Alex T. Nielsen ◽  
Wen-Tso Liu ◽  
Carlos Filipe ◽  
Leslie Grady ◽  
Søren Molin ◽  
...  

ABSTRACT The microbial diversity of a deteriorated biological phosphorus removal reactor was investigated by methods not requiring direct cultivation. The reactor was fed with media containing acetate and high levels of phosphate (P/C weight ratio, 8:100) but failed to completely remove phosphate in the effluent and showed very limited biological phosphorus removal activity. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA was used to investigate the bacterial diversity. Up to 11 DGGE bands representing at least 11 different sequence types were observed; DNA from the 6 most dominant of these bands was further isolated and sequenced. Comparative phylogenetic analysis of the partial 16S rRNA sequences suggested that one sequence type was affiliated with the alpha subclass of theProteobacteria, one was associated with theLegionella group of the gamma subclass of theProteobacteria, and the remaining four formed a novel group of the gamma subclass of the Proteobacteria with no close relationship to any previously described species. The novel group represented approximately 75% of the PCR-amplified DNA, based on the DGGE band intensities. Two oligonucleotide rRNA probes for this novel group were designed and used in a whole-cell hybridization analysis to investigate the abundance of this novel group in situ. The bacteria were coccoid and 3 to 4 μm in diameter and represented approximately 35% of the total population, suggesting a relatively close agreement with the results obtained by the PCR-based DGGE method. Further, based on electron microscopy and standard staining microscopic analysis, this novel group was able to accumulate granule inclusions, possibly consisting of polyhydroxyalkanoate, inside the cells.


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