scholarly journals Sulfide inhibition of nitrite oxidation in activated sludge depends on microbial community composition

2018 ◽  
Vol 138 ◽  
pp. 241-249 ◽  
Author(s):  
Jeseth Delgado Vela ◽  
Gregory J. Dick ◽  
Nancy G. Love
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Nitrite Oxidation ◽  
Sulfide Inhibition

scholarly journals Do initial concentration and activated sludge seasonality affect pharmaceutical biotransformation rate constants?

2021 ◽  
Author(s):  
Tamara J. H. M. van Bergen ◽  
Ana B. Rios-Miguel ◽  
Tom M. Nolte ◽  
Ad M. J. Ragas ◽  
Rosalie van Zelm ◽  
...  
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Community Composition ◽  
Rate Constants ◽  
Wastewater Treatment Plants ◽  
Microbial Community Composition ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Initial Concentration ◽  
Different Seasons

Abstract Pharmaceuticals find their way to the aquatic environment via wastewater treatment plants (WWTPs). Biotransformation plays an important role in mitigating environmental risks; however, a mechanistic understanding of involved processes is limited. The aim of this study was to evaluate potential relationships between first-order biotransformation rate constants (kb) of nine pharmaceuticals and initial concentration of the selected compounds, and sampling season of the used activated sludge inocula. Four-day bottle experiments were performed with activated sludge from WWTP Groesbeek (The Netherlands) of two different seasons, summer and winter, spiked with two environmentally relevant concentrations (3 and 30 nM) of pharmaceuticals. Concentrations of the compounds were measured by LC–MS/MS, microbial community composition was assessed by 16S rRNA gene amplicon sequencing, and kb values were calculated. The biodegradable pharmaceuticals were acetaminophen, metformin, metoprolol, terbutaline, and phenazone (ranked from high to low biotransformation rates). Carbamazepine, diatrizoic acid, diclofenac, and fluoxetine were not converted. Summer and winter inocula did not show significant differences in microbial community composition, but resulted in a slightly different kb for some pharmaceuticals. Likely microbial activity was responsible instead of community composition. In the same inoculum, different kb values were measured, depending on initial concentration. In general, biodegradable compounds had a higher kb when the initial concentration was higher. This demonstrates that Michealis-Menten kinetic theory has shortcomings for some pharmaceuticals at low, environmentally relevant concentrations and that the pharmaceutical concentration should be taken into account when measuring the kb in order to reliably predict the fate of pharmaceuticals in the WWTP. Key points • Biotransformation and sorption of pharmaceuticals were assessed in activated sludge. • Higher initial concentrations resulted in higher biotransformation rate constants for biodegradable pharmaceuticals. • Summer and winter inocula produced slightly different biotransformation rate constants although microbial community composition did not significantly change. Graphical abstract

Influence of flocculation and settling properties of activated sludge in relation to secondary settler performance

2006 ◽  
Vol 54 (1) ◽  
pp. 147-155 ◽  
Author(s):  
B.-M. Wilén ◽  
M. Onuki ◽  
M. Hermansson ◽  
D. Lumley ◽  
T. Mino
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Community Composition ◽  
In Situ Hybridisation ◽  
Microbial Community Composition ◽  
Treatment Plant ◽  
Plant Performance ◽  
Fluorescence In Situ Hybridisation ◽  
Trickling Filters ◽  
Floc Structure

Floc characteristics were studied at a full scale activated sludge treatment plant with a unique process solution incorporating pre-denitrification with post-nitrification in nitrifying trickling filters. Since greater nitrogen removal is achieved when more secondary settled wastewater is recirculated to the trickling filters, the secondary settlers are always operated close to their maximal capacity. The flocculation and settling properties are therefore crucial and have an effect on the overall plant performance. Since the plant is operated at a short sludge age, these properties change quickly, resulting in variable maximal secondary settler capacity. The dynamics in floc structure and microbial community composition were studied and correlated to the secondary settler performance. Fluorescence in situ hybridisation was used to investigate the microbial community structure and their spatial distribution. The floc structure could to some extent be related to the flocculation and settling properties of the sludge. Even small differences had an influence suggesting that colloidal properties also play a significant role in determining the floc properties. No correlation between microbial community composition and settling properties could be established with the group-specific probes investigated.

Application of a novel molecular technique to characterise the effect of settling on microbial community composition of activated sludge

2019 ◽  
Vol 251 ◽  
pp. 109594 ◽  
Author(s):  
Luong N. Nguyen ◽  
Audrey S. Commault ◽  
Md Abu Hasan Johir ◽  
Heriberto Bustamante ◽  
Robert Aurisch ◽  
...  
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Molecular Technique

scholarly journals Do initial concentration and activated sludge seasonality affect pharmaceutical biodegradation rate constants?

2020 ◽  
Author(s):  
Tamara J.H.M. van Bergen ◽  
Ana B. Rios-Miguel ◽  
Tom M. Nolte ◽  
Ad M.J. Ragas ◽  
Rosalie van Zelm ◽  
...  
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Community Composition ◽  
Rate Constants ◽  
Wastewater Treatment Plants ◽  
Microbial Community Composition ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Biodegradation Rate ◽  
Initial Concentration

AbstractPharmaceuticals find their way to the aquatic environment via wastewater treatment plants (WWTPs) and biodegradation plays an important role in mitigating environmental risks, however a mechanistic understanding of involved processes is limited. The aim of this study was to evaluate potential relationships between first-order biodegradation rate constants (kb) of nine pharmaceuticals and initial concentration of the selected compounds, and sampling season of the used activated sludge inocula. Four-day bottle experiments were performed with activated sludge from WWTP Groesbeek (The Netherlands) of two different seasons, summer and winter, spiked with two environmentally relevant concentrations (3 and 30 nM) of pharmaceuticals. Concentrations of the compounds were measured by LC-MS/MS, microbial community composition was assessed by 16S rRNA gene amplicon sequencing and kbvalues were calculated. The biodegradable pharmaceuticals, ranked from high to low biodegradation rates, were acetaminophen, metformin, metoprolol, terbutaline, and phenazone. Carbamazepine, diatrizoic acid, diclofenac and fluoxetine were not converted. Summer and winter inocula did not show significant differences in microbial community composition, but resulted in a slightly different kbfor some pharmaceuticals. Likely microbial activity was responsible instead of community composition. In the same inoculum different kbvalues were measured, depending on initial concentration. In general, biodegradable compounds had a higher kbwhen the initial concentration was higher. This demonstrates that Michealis-Menten kinetics theory has shortcomings for some pharmaceuticals at low, environmentally relevant concentrations and that the pharmaceutical concentration should be taken into account when measuring the kbin order to reliably predict the fate of pharmaceuticals in the WWTP.

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