scholarly journals Removal of tetracyclines in wastewater : accumulation and distribution of chlortetracycline in bulk water and biomass compartments in activated sludge

2021 ◽  
Author(s):  
Ruba F. Farkh
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Ethylenediaminetetraacetic Acid ◽  
Divalent Cations ◽  
Bulk Water ◽  
Microbial Cells ◽  
Initial Concentration ◽  
Anoxic Conditions ◽  
Polymeric Substance ◽  
The Impact

A study was conducted to examine the removal of chlortetracycline and its distribution and accumulation in three compartments; bulk water, extracellular polymeric substance (EPS) and the microbial cells in activated sludge. Also the effect of different environmental conditions on the distribution and accumulation in the three compartments was investigated. Effluent samples collected from a municipal activated sludge treatment system were set up in bath experiments to test the distribution and accumulation of chlortetracycline under aerobic and anoxic conditions for 14 days. In addition, the impact of the activity of the microbial community on the amassing of the antibiotic in the biomass was examined. The effect of divalent cations on import and accumulation of chlortetracycline was tested. Sorption in believed to be the main removal pathway in wastewater treatment systems for tetracyclines in general and chlortetracycline in particular. In this study that notion was confirmed, and it was found that the removal via sorption under anoxic condition (43.2%) is almost double of that under aerobic conditions (27.0%). The amount of what accumulated in the cells compared to that sorbed in the EPS is twice as much in the former and triple as much in the latter. These findings suggest that changes in the structure and charge of the EPS could be the reason of higher accumulation in the polymeric substance. The impact of microbial activity on the sorption and distribution of the chlortetracycline in the three compartments showed almost a similar behaviour to that under aerobic and anoxic conditions. It was clear that the more viable the microbial community, the less the antibiotic accumulated in the [sic] both biomass compartments; the EPS and microbial cells. Biomass with inhibited respiration accrued 90% of the initial concentration; where as the active microbial community was more resistant and only 24.2% of the initial concentration accumulated within the cells. The findings suggest that the antibiotic makes its way to the cells thus bypassing the EPS, and is trapped in the EPS as it is pumped out of the cells in an energy dependent mechanism. The presence of ethylenediaminetetraacetic acid (EDTA) which is a strong chelator had no import effect. Nevertheless it did indicate that the accumulation in the EPS could be attributed to the presence of cations since there was a high negative correlation (-0.98) between the disappearance of the antibiotic from the EPS compartment and the EDTA concentration used in incubation.

scholarly journals Removal of tetracyclines in wastewater : accumulation and distribution of chlortetracycline in bulk water and biomass compartments in activated sludge

2021 ◽  
Author(s):  
Ruba F. Farkh
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Ethylenediaminetetraacetic Acid ◽  
Divalent Cations ◽  
Bulk Water ◽  
Microbial Cells ◽  
Initial Concentration ◽  
Anoxic Conditions ◽  
Polymeric Substance ◽  
The Impact

A study was conducted to examine the removal of chlortetracycline and its distribution and accumulation in three compartments; bulk water, extracellular polymeric substance (EPS) and the microbial cells in activated sludge. Also the effect of different environmental conditions on the distribution and accumulation in the three compartments was investigated. Effluent samples collected from a municipal activated sludge treatment system were set up in bath experiments to test the distribution and accumulation of chlortetracycline under aerobic and anoxic conditions for 14 days. In addition, the impact of the activity of the microbial community on the amassing of the antibiotic in the biomass was examined. The effect of divalent cations on import and accumulation of chlortetracycline was tested. Sorption in believed to be the main removal pathway in wastewater treatment systems for tetracyclines in general and chlortetracycline in particular. In this study that notion was confirmed, and it was found that the removal via sorption under anoxic condition (43.2%) is almost double of that under aerobic conditions (27.0%). The amount of what accumulated in the cells compared to that sorbed in the EPS is twice as much in the former and triple as much in the latter. These findings suggest that changes in the structure and charge of the EPS could be the reason of higher accumulation in the polymeric substance. The impact of microbial activity on the sorption and distribution of the chlortetracycline in the three compartments showed almost a similar behaviour to that under aerobic and anoxic conditions. It was clear that the more viable the microbial community, the less the antibiotic accumulated in the [sic] both biomass compartments; the EPS and microbial cells. Biomass with inhibited respiration accrued 90% of the initial concentration; where as the active microbial community was more resistant and only 24.2% of the initial concentration accumulated within the cells. The findings suggest that the antibiotic makes its way to the cells thus bypassing the EPS, and is trapped in the EPS as it is pumped out of the cells in an energy dependent mechanism. The presence of ethylenediaminetetraacetic acid (EDTA) which is a strong chelator had no import effect. Nevertheless it did indicate that the accumulation in the EPS could be attributed to the presence of cations since there was a high negative correlation (-0.98) between the disappearance of the antibiotic from the EPS compartment and the EDTA concentration used in incubation.

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

scholarly journals Impact of NaCl, nitrate and temperature on the microbial community of a methanol-fed, denitrifying marine biofilm

2019 ◽  
Author(s):  
Richard Villemur ◽  
Geneviève Payette ◽  
Valérie Geoffroy ◽  
Florian Mauffrey ◽  
Christine Martineau
Keyword(s):  
Microbial Community ◽  
Environmental Changes ◽  
Heterotrophic Bacteria ◽  
Denitrifying Bacteria ◽  
Metagenomic Data ◽  
Strong Impact ◽  
Anoxic Conditions ◽  
Pure Cultures ◽  
Denitrification Genes ◽  
The Impact

AbstractBackgroundThe biofilm of a continuous, methanol-fed, fluidized denitrification system that treated a marine effluent at the Montreal Biodome is composed of a multi-species microbial community, among whichHyphomicrobium nitrativoransNL23 andMethylophaga nitratireducenticrescensJAM1 are the principal bacteria involved in the denitrifying activities. To assess its resilience to environmental changes, the biofilm taken from the denitrification system was cultured at laboratory scale in artificial seawater (ASW) under anoxic conditions and exposed to a range of specific physico-chemical parameters. We previously showed that the seawater formulation and the NaCl concentrations had a strong impact on theH. nitrativoransNL23 population, with its displacement by a new denitrifier,M. nitratireducenticrescensGP59. Here, we report the impact of these cultures conditions on the dynamics of the overall microbial community of the denitrifying biofilm.MethodsThe original biofilm (OB) taken from the denitrification system was acclimated for five weeks in ASW under anoxic conditions with a range of NaCl concentrations, and with four combinations of nitrate concentrations and temperatures. The OB was also acclimated to the commercial Instant Ocean seawater medium (IO). The bacterial diversity of the biofilm cultures and the OB was determined by 16S ribosomal RNA amplicon metagenome sequencing. Culture-dependent approach was used to isolate other denitrifying bacteria from the biofilm cultures. The metatranscriptomes of some of the biofilm cultures were derived, along with the transcriptomes of planktonic pure cultures ofH. nitrativoransNL23 andM. nitratireducentricrescensGP59 cultivated under denitrifying conditions.ResultsThe 16S metagenomic data revealed very high proportions ofM. nitratireducenticrescensin the biofilm cultures.H. nitrativoransNL23 was found in high proportion in the OB, both was absent in the biofilm cultures with 2.75% NaCl in the ASW medium. It was found however in low proportions in the biofilm cultures with 0 to 1% NaCl in the ASW medium and in the IO biofilm cultures. Emergence ofMarinicellaspp. occurred in these biofilm cultures. Denitrifying bacterial isolates affiliated toMarinobacterspp. andParacoccusspp. were isolated. Up regulation of the denitrification genes in strains GP59 and NL23 occurred in the biofilm cultures compared to the planktonic pure cultures. Denitrifying bacteria affiliated to theStappiaspp. were metabolically active in the biofilm cultures.ConclusionsThese results illustrate the dynamics of the microbial community in the denitrifying biofilm cultures in adapting to different environmental conditions. The NaCl concentration is an important factor affecting the microbial community in the biofilm cultures. Up regulation of the denitrification genes in strain GP59 and strain NL23 in the biofilm cultures suggests different mechanisms of regulation of the denitrification pathway in the biofilm compared to the planktonic pure cultures. Other denitrifying heterotrophic bacteria are present in low proportions in the biofilm, suggesting that the biofilm has the potential to adapt to heterotrophic, non-methylotrophic environments.

Monitoring cations to predict and improve activated sludge settling and dewatering properties of industrial wastewaters

1998 ◽  
Vol 38 (3) ◽  
pp. 119-126 ◽  
Author(s):  
Sudhir N. Murthy ◽  
John T. Novak ◽  
Robert D. De Haas
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Divalent Cations ◽  
Treatment Plant ◽  
Field Tests ◽  
Ammonium Ion ◽  
Ammonium Ions ◽  
High Concentration ◽  
The Impact

Laboratory and field tests were conducted on activated sludge from an industrial wastewater treatment plant in order to monitor the settling and dewatering properties and to assess the impact cations may have on these properties. The influent to the wastewater treatment plant contained a high concentration of sodium ions and a low concentration of divalent cations. The sludge exhibited poor settling and dewatering properties. Initial laboratory results indicated an improvement in settling and dewatering properties through the addition of calcium and magnesium. After addition of magnesium during field trials, floc density and settling properties improved considerably. In addition, residual ammonium ions in the mixed liquor appeared to interact with the activated sludge flocs to influence their dewatering properties. It was observed that an increase in ammonium ion in the soluble sludge fraction was related to deterioration in the dewatering properties. During these trials, the ammonium ions demonstrated a greater influence on dewatering properties than did the magnesium ions. The tests conducted at the treatment plant revealed that complex interactions between cations and sludge influenced the settling and dewatering properties in a manner that depended on ratios and concentrations of monovalent and divalent cations in the activated sludge feed and solution.

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.

The impact of zinc oxide nanoparticles on phosphorus removal and the microbial community in activated sludge in an SBR

RSC Advances ◽  
2016 ◽  
Vol 6 (99) ◽  
pp. 96706-96713 ◽  
Author(s):  
S. T. Wang ◽  
W. Q. Wang ◽  
Z. R. Zhang ◽  
H. You
Keyword(s):  
Zinc Oxide ◽  
Microbial Community ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Zinc Oxide Nanoparticles ◽  
Cell Membranes ◽  
Oxide Nanoparticles ◽  
Zno Nps ◽  
The Impact

10 and 20 mg L−1 ZnO NPs damaged the integrity of cell membranes and the microbial community and affected phosphorus removal.

scholarly journals Dynamics of a methanol-fed marine denitrifying biofilm: 2—impact of environmental changes on the microbial community

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7467 ◽  
Author(s):  
Richard Villemur ◽  
Geneviève Payette ◽  
Valérie Geoffroy ◽  
Florian Mauffrey ◽  
Christine Martineau
Keyword(s):  
Microbial Community ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Heterotrophic Bacteria ◽  
Denitrifying Bacteria ◽  
Anoxic Conditions ◽  
Nacl Concentration ◽  
Pure Cultures ◽  
Denitrification Genes ◽  
The Impact

Background The biofilm of a methanol-fed, marine denitrification system is composed of a multi-species microbial community, among which Hyphomicrobium nitrativorans and Methylophaga nitratireducenticrescens are the principal bacteria involved in the denitrifying activities. To assess its resilience to environmental changes, the biofilm was cultivated in artificial seawater (ASW) under anoxic conditions and exposed to a range of specific environmental conditions. We previously reported the impact of these changes on the denitrifying activities and the co-occurrence of H. nitrativorans strain NL23 and M. nitratireducenticrescens in the biofilm cultures. Here, we report the impact of these changes on the dynamics of the overall microbial community of the denitrifying biofilm. Methods The original biofilm (OB) taken from the denitrification system was cultivated in ASW under anoxic conditions with a range of NaCl concentrations, and with four combinations of nitrate/methanol concentrations and temperatures. The OB was also cultivated in the commercial Instant Ocean seawater (IO). The bacterial diversity of the biofilm cultures and the OB was determined by 16S ribosomal RNA gene sequences. Culture approach was used to isolate other denitrifying bacteria from the biofilm cultures. The metatranscriptomes of selected biofilm cultures were derived, along with the transcriptomes of planktonic pure cultures of H. nitrativorans strain NL23 and M. nitratireducenticrescens strain GP59. Results High proportions of M. nitratireducenticrescens occurred in the biofilm cultures. H. nitrativorans strain NL23 was found in high proportion in the OB, but was absent in the biofilm cultures cultivated in the ASW medium at 2.75% NaCl. It was found however in low proportions in the biofilm cultures cultivated in the ASW medium at 0–1% NaCl and in the IO biofilm cultures. Denitrifying bacterial isolates affiliated to Marinobacter spp. and Paracoccus spp. were isolated. Up regulation of the denitrification genes of strains GP59 and NL23 occurred in the biofilm cultures compared to the planktonic pure cultures. Denitrifying bacteria affiliated to the Stappia spp. were metabolically active in the biofilm cultures. Conclusions These results illustrate the dynamics of the microbial community in the denitrifying biofilm cultures in adapting to different environmental conditions. The NaCl concentration is an important factor affecting the microbial community in the biofilm cultures. Up regulation of the denitrification genes of M. nitratireducenticrescens strain GP59 and H. nitrativorans strain NL23 in the biofilm cultures suggests different mechanisms of regulation of the denitrification pathway in the biofilm. Other denitrifying heterotrophic bacteria are present in low proportions, suggesting that the biofilm has the potential to adapt to heterotrophic, non-methylotrophic environments.

The Impact of a Chemostat Discharge Containing Oil Degrading Bacteria on the Biological Kinetics of a Refinery Activated Sludge Process

1988 ◽  
Vol 20 (11-12) ◽  
pp. 131-136 ◽  
Author(s):  
A. D. Wong ◽  
C. D. Goldsmith
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Waste Treatment ◽  
Treatment Plant ◽  
Utilization Rate ◽  
Activated Sludge Process ◽  
Kinetic Evaluation ◽  
Degrading Bacteria ◽  
Waste Treatment Plant ◽  
The Impact

The effect of discharging specific oil degrading bacteria from a chemostat to a refinery activated sludge process was determined biokinetically. Plant data for the kinetic evaluation of the waste treatment plant was collected before and during treatment. During treatment, the 500 gallon chemostatic growth chamber was operated on an eight hour hydraulic retention time, at a neutral pH, and was fed a mixture of refinery wastewater and simple sugars. The biokinetic constants k (days−1), Ks (mg/L), and K (L/mg-day) were determined before and after treatment by Monod and Lineweaver-Burk plots. Solids discharged and effluent organic concentrations were also evaluated against the mean cell retention time (MCRT). The maximum utilization rate, k, was found to increase from 0.47 to 0.95 days−1 during the operation of the chemostat. Subsequently, Ks increased from 141 to 556 mg/L. Effluent solids were shown to increase slightly with treatment. However, this was acceptable due to the polishing pond and the benefit of increased ability to accept shock loads of oily wastewater. The reason for the increased suspended solids in the effluent was most likely due to the continual addition of bacteria in exponential growth that were capable of responding to excess substrate. The effect of the chemostatic addition of specific microbial inocula to the refinery waste treatment plant has been to improve the overall organic removal capacity along with subsequent gains in plant stability.

Effects of pH shock on microaerobic activated sludge system with a graphene oxide/nano-magnetic powder composite

2020 ◽  
Vol 35 (3) ◽  
pp. 457-463
Author(s):  
Huixia Lan ◽  
Xiangzhi Wang ◽  
Shixin Qi ◽  
Da Yang ◽  
Hao Zhang
Keyword(s):  
Graphene Oxide ◽  
Activated Sludge ◽  
High Throughput Sequencing ◽  
Impact Resistance ◽  
Magnetic Powder ◽  
Blank Group ◽  
Activated Sludge System ◽  
Ph Shock ◽  
Dominant Bacteria ◽  
The Impact

AbstractUsing the acclimated activated sludge from the pulping middle-stage effluent, the effect of pH shock on the micro-oxygen activated sludge system with a nano-magnetic powder/graphene oxide composite was studied. The results showed that the removal rates of chemical oxygen demand (CODCr) and ultraviolet adsorption at 254 nm (UV254) decreased. Also, the sludge settling performance was poor due to the impact of pH, but the impact resistance of nano-magnetic powder/graphene oxide group (MGO group) was higher and the recovery was faster. Results of high throughput sequencing indicated that the diversity of microbial community was reduced by the impact of pH, but it was significantly higher in MGO group than in the blank group. The dominant bacteria after pH shock or recovery in both of the system had a large difference. The percentage of the dominant bacteria in the MGO group was higher than that in the blank group. The MGO group had higher electron transfer system (ETS) activity which made the system having a strong pH impact resistance.

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