Bacteria and Protozoa Population Dynamics in Biological Phosphate Removal Systems

1994 ◽  
Vol 29 (7) ◽  
pp. 109-117 ◽  
Author(s):  
J. S. Čech ◽  
P. Hartman ◽  
M. Macek
Keyword(s):  
Population Dynamics ◽  
Phosphorus Removal ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Sole Source ◽  
Phosphate Removal ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
System Collapse ◽  
Biological Phosphorus

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.

Analysis of microbial community that performs enhanced biological phosphorus removal in activated sludge fed with acetate

2002 ◽  
Vol 46 (1-2) ◽  
pp. 145-154 ◽  
Author(s):  
M. Onuki ◽  
H. Satoh ◽  
T. Mino
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Batch Reactor ◽  
Phosphate Removal ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Dominant Band ◽  
Biological Phosphorus

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.

Morphological characteristics of microbial sludge performing enhanced biological phosphorus removal in a sequencing batch reactor fed with glucose as sole carbon source

2000 ◽  
Vol 41 (12) ◽  
pp. 79-84 ◽  
Author(s):  
C. O. Jeon ◽  
D. S. Lee ◽  
J. M. Park
Keyword(s):  
Phosphorus Removal ◽  
Sole Carbon Source ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Morphological Characteristics ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Electron Microscopic ◽  
Biological Phosphorus ◽  
Polyphosphate Granules

Electron microscopic analysis was used to analyse the morphological characteristics of microbial sludge performing enhanced biological phosphorus removal (EBPR) in an anaerobic/aerobic sequencing batch reactor (SBR) fed with glucose as the sole carbon source. The amounts of phosphate release and uptake during the SBR cycle gradually increased with operation time and complete EBPR was achieved after about 90 days. Scanning electron microscopy (SEM) showed that the initial sludge inoculated into the SBR consisted of various microorganisms such as coccus-, rod- and bacillus-shaped bacteria, but after extended operation (more than 650 days) perpendicular cuboidal bacteria of eight coccus-shaped cells dominated the microbial sludge in the SBR reactor. The cell size of the cuboidal bacteria was about 0.7 μm in diameter. In the sludge, coccus- and rod-shaped bacteria also existed but at much lower frequency. Transmission electron microscopy (TEM) also revealed that the cuboidal bacteria dominated the sludge, but they did not contain polyphosphate granules or glycogen inclusions. The rod-shaped bacteria did not contain polyphosphate granules or glycogen inclusions either. Only coccus-shaped bacteria with a diameter of about 1.2 μm contained small black polyphosphate granules and a large white inclusion. Based on previously proposed metabolic pathways and electron microscopic results, it was inferred that the dominating cuboidal bacteria were lactic acid producing organisms (LPO) and the coccus-shaped bacteria were lactate-using phosphorus accumulating organisms (PAO).

The influence of different substrates on enhanced biological phosphorus removal in a sequencing batch reactor

1997 ◽  
Vol 35 (1) ◽  
pp. 75-80 ◽  
Author(s):  
R. Tasli ◽  
N. Artan ◽  
D. Orhon
Keyword(s):  
Phosphorus Removal ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
The Other ◽  
Organic Substrates ◽  
Relative Importance ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Batch Tests ◽  
Biological Phosphorus

All models of enhanced biological phosphorus removal (EBPR) define fermentable readily biodegradable substrate, without emphasizing the significance of its composition and the relative importance of different substrates. On the other hand, it is also known that substrates like glucose may be utilized without requiring poly-P energy, a phenomenon which deteriorates the EBPR performance. This paper reports an experimental study evaluating the effect of different organic substrates and their combinations on EBPR, in a sequencing batch reactor. Experimental data show that the EBPR efficiency is significantly affected by the increase of the glucose fraction in the feed, due to the probable dominance of G bacteria. Results of anaerobic batch tests also support this evaluation.

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