scholarly journals MICROBIOME ANALYSIS OF THE BACTERIAL POPULATION IN A BENCH-SCALE-ACTIVATED SLUDGE REACTOR EXPOSED TO AN ARTIFICIAL INSECTICIDE SPILL

2020 ◽  
Author(s):  
ÁNGELA BAEZA-SERRANO ◽  
MARIA JOSÉ TÁRREGA ◽  
JUAN F. MARTÍNEZ-BLANCH ◽  
ANTONIA ROJAS ◽  
MARTA TORTAJADA ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Bacterial Population ◽  
Bench Scale ◽  
Microbiome Analysis ◽  
Activated Sludge Reactor

scholarly journals Bacterial Population Dynamics in a Laboratory Activated Sludge Reactor Monitored by Pyrosequencing of 16S rRNA

2013 ◽  
Vol 28 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Hiroyasu Satoh ◽  
Kenshiro Oshima ◽  
Wataru Suda ◽  
Purnika Ranasinghe ◽  
Ning Li ◽  
...  
Keyword(s):  
Population Dynamics ◽  
16S Rrna ◽  
Activated Sludge ◽  
Bacterial Population ◽  
Activated Sludge Reactor

Variation in Sludge Settleability with Temperature

1980 ◽  
Vol 15 (1) ◽  
pp. 73-82 ◽  
Author(s):  
J.G. Henry ◽  
E.E. Salenieks
Keyword(s):  
Activated Sludge ◽  
Effect Of Temperature ◽  
Organic Load ◽  
Limiting Factor ◽  
Appreciable Effect ◽  
Loading Rates ◽  
Bench Scale ◽  
Filamentous Bulking ◽  
Filamentous Microorganisms ◽  
Sludge Settleability

Abstract This study examined the effect of temperature on the settleabi1ity of activated sludge at various organic loading rates. Five completely mixed, bench-scale, activated sludge plants, operating under similar conditions at 5, 10 and 19°C, were continuously fed diluted, settled sewage supplemented with carbohydrate (sucrose). Hydraulic loading rates, MLSS and pH were maintained at constant levels during the experiments to eliminate these factors are variables. Dissolved oxygen was kept in excess of 3 mg/1 so that it would not be a limiting factor. Sludge Volume Indices (SVI ) and zone settling velocities were used to indicate changes in sludge settleability. Microscopic examination of the activated sludge indicated significant differences in the morphological features of filamentous microorganisms present at the two temperature extremes. At 19°C, the predominant forms were characterized by long curving trichomes, occasionally falsely branching, containing short cylindrical cells. At 5 °C, much smaller straight filaments, composed of long, narrow, rod-shaped cells appeared to be the principal microorganisms responsible for bulking. Various other filamentous forms were always present at each of the temperatures studied. Stirred sludge settling tests of moderately bulking sludges generally exhibited much higher settling velocities and lower SVI's than unstirred bulking samples. However, extremely filamentous bulking sludge exhibited comparable stirred and unstirred settling velocity and SVI values. The standard SVI test was found to be an inadequate indicator of the extent of bulking when trying to correlate the SVI failures from bench-scale performance with the results from continuous units. Lower temperature had no appreciable effect on COD removal efficiency as long as bulking did not cause a loss of solids in the effluent. However, results suggested that less than half the organic load could be accepted at 5°C, that could be handled at 19°C, before filamentous bulking occurred. A plot of loading versus temperature for various SVI's provided a visual indication of the safe loading limit below which bulking was unlikely to occur. The study clearly demonstrated that temperature can have a significant effect on sludge settleability.

Nitrification in activated sludge batch reactors is linked to protozoan grazing of the bacterial population

2005 ◽  
Vol 51 (9) ◽  
pp. 791-799 ◽  
Author(s):  
Penny Petropoulos ◽  
Kimberley A Gilbride
Keyword(s):  
Activated Sludge ◽  
Bacterial Population ◽  
Grazing Pressure ◽  
Nitrification Rate ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Bacterial Concentration ◽  
Batch Cultures ◽  
Protozoan Grazing ◽  
Swimming Bacteria

Protozoa feed upon free-swimming bacteria and suspended particles inducing flocculation and increasing the turnover rate of nutrients in complex mixed communities. In this study, the effect of protozoan grazing on nitrification was examined in activated sludge in batch cultures maintained over a 14-day period. A reduction in the protozoan grazing pressure was accomplished by using either a dilution series or the protozoan inhibitor cycloheximide. As the dilutions increased, the nitrification rate showed a decline, suggesting that a reduction in protozoan or bacterial concentration may cause a decrease in nitrification potential. In the presence of cycloheximide, where the bacterial concentration was not altered, the rates of production of ammonia, nitrite, and nitrate all were significantly lower in the absence of active protozoans. These results suggest that a reduction in the number or activity of the protozoans reduces nitrification, possibly by limiting the availability of nutrients for slow-growing ammonia and nitrite oxidizers through excretion products. Furthermore, the ability of protozoans to groom the heterotrophic bacterial population in such systems may also play a role in reducing interspecies competition for nitrification substrates and thereby augment nitrification rates.Key words: nitrification, activated sludge, protozoan grazing, ammonia-oxidizing bacteria, cycloheximide.

scholarly journals Systematic Multimodeling Methodology Applied to an Activated Sludge Reactor Model

2010 ◽  
Vol 49 (6) ◽  
pp. 2790-2799 ◽  
Author(s):  
Anca Maria Nagy ◽  
Gilles Mourot ◽  
Benoît Marx ◽  
José Ragot ◽  
Georges Schutz
Keyword(s):  
Activated Sludge ◽  
Reactor Model ◽  
Activated Sludge Reactor

Disturbance observer for estimation of oxygen uptake rate in an activated sludge reactor

2016 ◽  
Author(s):  
Francisco Jadilson dos Santos Silva ◽  
Euler C. T. de Macedo ◽  
Sebastian Y. C. Catunda ◽  
Carlos E. T. Dorea ◽  
Adrianus C. Van Haandel
Keyword(s):  
Oxygen Uptake ◽  
Activated Sludge ◽  
Uptake Rate ◽  
Disturbance Observer ◽  
Oxygen Uptake Rate ◽  
Activated Sludge Reactor
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