Monitoring of the microbial community of a sequencing batch reactor bioaugmented to improve its phosphorus removal capabilities

2001 ◽  
Vol 43 (3) ◽  
pp. 1-8 ◽  
Author(s):  
P. Dabert ◽  
A. Fleurat-Lessard ◽  
E. Mounier ◽  
J.-P. Delgenès ◽  
R. Moletta ◽  
...  

The acclimatisation of an activated sludge to enhanced biological phosphorus removal conditions was followed after and without bioaugmentation with a low amount of phosphorus-accumulating sludge. Phosphorus removal yields were monitored by conventional analytical methods and microbial communities evolutions were followed by a finger printing molecular technique (PCR-SSCP). While the benefit of the bioaugmentation seems real at the level of the reactor parameters, bioaugmentation speeded up the installation of good and stable phosphorus removal yield, the establishment of the inoculated microbial community in the bioaugmented reactor is still unclear. Both the bioaugmented and the control microbial communities evolved in a similar way to end up with apparently comparable populations. At the time of the experiment, the results suggest that the microbial community inoculated for the bioaugmentation did not establish in the reactor but compensated for phosphorus accumulation until the acclimatisation of an endogenous microbial community arose.

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.


1997 ◽  
Vol 36 (12) ◽  
pp. 55-60 ◽  
Author(s):  
S. W. Oa ◽  
E. Choi

Phosphorus removal characteristics are rather complicated in a highly nitrogenous waste like nightsoil under treatment with SBR (sequencing batch reactor). It was found that the increased pH due to denitrification in anaerobic period stimulated chemical precipitation of phosphorus as struvite and hydroxyapatite, and the depressed pH due to nitrification in the aerobic period dissolved the previously formed precipitates. Phosphate accumulating organisms (PAO) worked as in the ordinary BNR (biological nutrient removal) systems regardless of the chemical reactions, but the chemical reactions masked the biological phosphorus release and uptake reactions. About 36% of phosphorus applied was removed biologically in polyphosphate granules. P-fractionation of sludges confirmed this phenomenon. Biological phosphorus removal could be increased with the increased anaerobic period. The morphological types of phosphorus precipitates were examined by SEM in combination with x-ray diffraction.


1993 ◽  
Vol 28 (10) ◽  
pp. 275-282 ◽  
Author(s):  
S. Marklund

The aeration tank in a small scale wastewater treatment plant was converted to a sequencing batch reactor (SBR) with a maximum volume of approx. 27 m3. The main purpose of this study was to examine low temperature biological phosphorus removal (BPR). The wastewater temperature varied during the study between 3 and 8°C, with a water temperature at or below 5°C during 7 months of the year. The SBR unit has been in operation from the end of 1989, the study period discussed here covered July 1991 - December 1992. SBR cycle time was varied between 6 and 12 hours, giving a total daily treatment capacity of between 18 and 36 m3. The influent biological oxygen demand - 7 days (BOD7) levels varied between 88 and 165 mg/l. Corresponding phosphorus levels were between 3.10 and 9.55 mg/l The mean effluent level of phosphorus was 1.57 mg/l and the BOD7 value was 23 mg/l. This gives a mean total phosphorus reduction of 74% and a BOD7 reduction of 81 %. During the study, mean supernatant suspended solids (SS) levels were quite high, at around 36 mg/l. This high SS level contributed a major part of both outlet phosphorus as well as BOD7 value. Effluent soluble values for phosphorus and BOD7 were 0.79 mg/l and 9 mg/l. The supernatant SS component of BOD7 and phosphorus increased at lower temperatures. It was not possible to reduce or balance this increase by increased cycle time or increased settling time within the maximum cycle time available (12 hours). Stable low supernatant phosphorus and BOD7 levels are thus to a large degree controlled by the effluent SS level. A maximum of 20 mg/l supernatant SS is necessary to reach target supernatant values of less than 1 mg/l of phosphorus and 15 mg/l of BOD7.


Sign in / Sign up

Export Citation Format

Share Document