Interfacing phylogenetic oligonucleotide probe hybridizations with representations of microbial populations and specific growth rates in mathematical models of activated sludge processes

1999 ◽  
Vol 39 (1) ◽  
1991 ◽  
Vol 23 (4-6) ◽  
pp. 755-763 ◽  
Author(s):  
M. Okada ◽  
A. Murakami ◽  
C. K. Lin ◽  
Y. Ueno ◽  
T. Okubo

Laboratory-scale sequencing batch reactor (SBR) activated sludge processes were operated using synthetic wastewater to clarify the effects of sludge retention time(SRT) and organic substrates on the accumulation of bio-P-bacteria. The accumulation of bio-P-bacteria could be enhanced by wide variation in concentration of organic substrates by giving a short fill period and sufficient anaerobic conditions. However, the accumulation could not be enhanced in the reactor operated with SRT less than 25 d in spite of the higher, more than 0.1 d−1, specific growth rates observed in the isolated strains of bio-P-bacteria. The specific growth rates of bio-P-bacteria were estimated at 0.040 d−1, 0.030 d−1 and 0.035 d−1 in the SBR activated sludge processes fed with sodium acetate (A), glucose and polypeptone (GP) and polypeptone (P), respectively. Therefore, a large sludge retention time would be necessary for the accumulation of bio-P-bacteria. Volatile fatty acids (VFA), such as sodium acetate (A), seemed to be more effective than other organic substrates (GP and P) for the accumulation of bio-P-bacteria in activated sludge ecosystems.


1992 ◽  
Vol 26 (9-11) ◽  
pp. 2125-2128 ◽  
Author(s):  
J. Bower Carberry ◽  
L. E. Kovach

The white rot fungus Phanerochaete chrysosporium can degrade toxic compounds under specific nutrient conditions. This attribute was utilized in order to determine the effect of fungal pretreatment on model compounds pentachlorophenol and toluene. The fungal culture was purchased from ATCC, cultured on dextrose agar, and the mycelia harvested to degrade the model compounds. P. chrysosporium was able to degrade up to 74% of initial pentachlorophenol concentration in eight days and up to 31% initial toluene in 31 hours. Specific growth rates of activated sludge and selected microbial consortia were determined on untreated and fungal-pretreated parent model compounds. Specific growth rates for activated sludge and selected microbial consortia were enhanced by fungal pretreatment of both model compounds. Specific growth rates indicated more efficient use of toluene by activated sludge than by toluene-selected microbial consortia, while pentachlorophenol- selected microbial consortia exhibited more favorable growth rates on pentachlorophenol than did activated sludge. Pretreatment results indicated that the toxicity of model compounds was reduced by fungal pretreatment. The growth rates were compared and used as an indication of toxicity reduction which can be exploited at contaminated waste sites or at industrial pretreatment facilities.


2001 ◽  
Vol 58 (2) ◽  
pp. 386-393 ◽  
Author(s):  
John A Sweka ◽  
Kyle J Hartman

Brook trout (Salvelinus fontinalis) were held in an artificial stream to observe the influence of turbidity on mean daily consumption and specific growth rates. Treatment turbidity levels ranged from clear (<3.0 nephelometric turbidity units (NTU)) to very turbid water (> 40 NTU). Observed mean daily specific consumption rates were standardized to the mean weight of all brook trout tested. Turbidity had no significant effect on mean daily consumption, but specific growth rates decreased significantly as turbidity increased. Brook trout in turbid water became more active and switched foraging strategies from drift feeding to active searching. This switch was energetically costly and resulted in lower specific growth rates in turbid water as compared with clear water. Bioenergetics simulations were run to compare observed growth with that predicted by the model. Observed growth values fell below those predicted by the model and the difference increased as turbidity increased. Abiotic factors, such as turbidity, which bring about changes in the activity rates of fish, can have implications for the accuracy of predicted growth by bioenergetics models.


Copeia ◽  
1992 ◽  
Vol 1992 (4) ◽  
pp. 1098 ◽  
Author(s):  
Alan B. Bolten ◽  
Karen A. Bjorndal ◽  
Janice S. Grumbles ◽  
David W. Owens

2014 ◽  
Vol 17 (2) ◽  
pp. 346-363 ◽  
Author(s):  
Wout Overkamp ◽  
Onur Ercan ◽  
Martijn Herber ◽  
Antonius J. A. van Maris ◽  
Michiel Kleerebezem ◽  
...  

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