References of "Louvet, Jean-Noël"
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See detailDynamic assessment of the floc morphology, bacterial diversity and integron content of an activated sludge reactor processing hospital effluent
Stalder, Thibault; Alrhmoun, Moussab; Louvet, Jean-Noël ULg et al

in Environmental Science & Technology (2013)

The treatment of hospital effluents (HE) is a major concern, as they are suspected of disseminating drugs and antibiotic resistance determinants in the environment. In order to assess HE influence on ... [more ▼]

The treatment of hospital effluents (HE) is a major concern, as they are suspected of disseminating drugs and antibiotic resistance determinants in the environment. In order to assess HE influence on wastewater treatment plant biomass, lab scale conventional activated sludge systems (CAS) were continuously fed with real HE or urban effluent as a control. To gain insights into the main hurdles linked to HE treatment, we conducted a multiparameter study using classical physicochemical characterization, phase contrast and confocal laser 35 scaning microscopy, and molecular biology (i.e. pyrosequencing) tools. HE caused erosion of floc structure and the production of extracellular polymeric substances attributed to the development of floc forming bacteria. Adaptation of the sludge bacterial community to the HE characteristics, thus maintaining the purification performance of the biomass, was observed. Finally, the comparative metagenomic analysis of the CAS showed that HE 40 treatment resulted in an increase of class 1 resistance integrons (RIs) and the introduction of Pseudomonas spp. into the bacterial community. HE treatment did not reduce the CAS process performance; nevertheless it increases the risk of dissemination into the environment of bacterial species and genetic determinants (RIs) involved in antibiotic resistance acquisition. [less ▲]

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See detailMonitoring of slaughterhouse wastewater biodegradation in a SBR using fluorescence and UV–Visible absorbance
Louvet, Jean-Noël ULg; Homeky, Billy; Casellas, Magali et al

in Chemosphere (2013)

The aim of this study was to demonstrate that the effectiveness of slaughterhouse wastewater treatment by activated sludge could be enhanced through the use of optical techniques, such as UV–Visible ... [more ▼]

The aim of this study was to demonstrate that the effectiveness of slaughterhouse wastewater treatment by activated sludge could be enhanced through the use of optical techniques, such as UV–Visible absorbance and fluorescence spectroscopy, to estimate the hydraulic retention time necessary to remove the biodegradable chemical oxygen demand (COD). Two experiments were conducted. First, a batch aerobic degradation was performed on four wastewater samples collected from four different cattle processing sites in order to study the changes in the spectroscopic properties of wastewater during biodegradation. Second, a sequencing batch reactor was used in order to confirm that the wastewater fluorescence could be successfully used to monitor wastewater biodegradation in a pilot-scale experiment. Residual blood was the main source of organic matter in the wastewater samples. The absorbance at 416 nm, related to porphyrins, was correlated to the COD during wastewater biodegradation. The tryptophan-like/fulvic-like fluorescence intensity ratio was related to the extent of biodegradation. The COD removal efficiency ranged from 74% to 94% with an hydraulic retention time (HRT) of 23 h. A ratio of tryptophan-like/fulvic-like fluorescence intensities higher than 1.2 indicated incomplete biodegradation of the wastewater and the need to increase the HRT. [less ▲]

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See detailAssessment of the traffic induced soil compaction risk
Louvet, Jean-Noël ULg; Verswijvel, Johan; Abroughui, Khaoula et al

Scientific conference (2012, May 15)

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See detailEffet des antibiotiques sur le procédé de traitement des eaux par boues activées ; étude à l’échelle du pilote et du floc par microscopie 3D
Potier, Olivier; Louvet, Jean-Noël ULg; Pons, Marie-Noëlle et al

Conference (2012, February 02)

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See detailTraitement à la source d'eaux usées hospitalières par boues activées: faisabilité et impact sur la biomasse
Alrhmoun, Moussab; Louvet, Jean-Noël ULg; Stalder, Thibault et al

Conference (2012, February 01)

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See detailEffet de l'érythromycine sur le traitement par boues activées
Louvet, Jean-Noël ULg; Giammarino, Cinzia; Dumas, Dominique et al

Poster (2012)

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See detailTracer application at different scales for wastewater treatment: from bacteria to industrial plant
Potier, Olivier; Louvet, Jean-Noël ULg; Le Moullec, Yann et al

Conference (2011, June)

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See detailElectrocoagulation as a tertiary treatment for paper mill wastewater: Removal of non-biodegradable organic pollution and arsenic
Zodi, Salim; Louvet, Jean-Noël ULg; Michon, Clémence et al

in Separation & Purification Technology (2011), 81

The tertiary treatment of paper mill wastewaters was investigated by testing the effect of batch electrocoagulation for 90 min with two parallel iron or aluminum plates at two values of the current ... [more ▼]

The tertiary treatment of paper mill wastewaters was investigated by testing the effect of batch electrocoagulation for 90 min with two parallel iron or aluminum plates at two values of the current density (100 and 150 A/m2). Dissolved organic carbon removal ranged between 24% and 46%, and chemical oxygen demand removal ranged between 32% and 68%. UV–visible spectroscopy showed a reduction of the aromaticity of the treated effluent. The process was also very efficient for the removal of lignin-based pollution, characterized by the fluorescence of humic substances. Arsenic was selected as an example of a non-organic micropollutant and was also satisfactorily removed (from 4 to 0.5 lg/L). The settling characteristics of the sludge obtained after the electrocoagulation treatment were also evaluated. The sludge aptitude to settling is better with Fe electrodes than with Al electrodes. The experimental results obtained in the present study indicate that electrocoagulation treatment can be very effective and was capable of improving the paper mill wastewaters’ quality downstream of the biological treatment. [less ▲]

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See detailElectrocoagulation as a tertiary treatment for paper mill wastewater: Removal of non-biodegradable organic pollution and arsenic
Zodi, Salim; Louvet, Jean-Noël ULg; Michon, Clémence et al

in Separation & Purification Technology (2011), 81

The tertiary treatment of paper mill wastewaters was investigated by testing the effect of batch electrocoagulation for 90 min with two parallel iron or aluminum plates at two values of the current ... [more ▼]

The tertiary treatment of paper mill wastewaters was investigated by testing the effect of batch electrocoagulation for 90 min with two parallel iron or aluminum plates at two values of the current density (100 and 150 A/m 2 ). Dissolved organic carbon removal ranged between 24% and 46%, and chemical oxygen demand removal ranged between 32% and 68%. UV–visible spectroscopy showed a reduction of aromaticity of the treated effluent. The process was also very efficient for the removal of lignin-based pollution, characterized by the fluorescence of humic substances. Arsenic was selected as an example non-organic micropollutant and was also satisfactorily removed (from 4 to 0.5 lg/L). The settling characteristics of the sludge obtained after the electrocoagulation treatment were also evaluated. The sludge aptitude to settling is better with Fe electrodes than with Al electrodes. The experimental results obtained in the present study indicate that electrocoagulation treatment can be very effective and capable of improving the paper mill wastewaters’ quality downstream of the biological treatment. [less ▲]

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See detailSimultaneous Gram and viability staining on activated sludge exposed to erythromycin: 3D CLSM time-lapse imaging of bacterial disintegration
Louvet, Jean-Noël ULg; Attik, Ghania; Dumas, Dominique et al

in International Journal of Hygiene and Environmental Health (2011), 214

The effect of erythromycin on activated sludge bacteria according to their Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging. The fluorescent stains ... [more ▼]

The effect of erythromycin on activated sludge bacteria according to their Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging. The fluorescent stains SYTOX Green and Texas Red-X conjugate of wheat germ agglutinin stained dying bacteria and Gram + bacteria respectively. Time-lapse imaging allowed an understanding of the staining mechanism and the measurement of the death rate. In presence of erythromycin (10 mg/L), Gram + bacteria had a higher mortality rate than the Gram − bacteria. This result suggests that antibiotic in wastewater could change the activated sludge bacteria composition, according to their Gram type by selecting the bacteria which are the least sensitive to the antibiotics. However bacterial death was followed by bacterial disintegration leading to a decrease in the fluorescence. Results suggested that the viability indicators based on membrane integrity should be used with a correct sampling method, which can give the initial quantity of living bacteria. [less ▲]

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See detailEffets des antibiotiques sur le procédé d'épuration par boues activées. Etude du cas de l'érythromycine, du floc bactérien au réacteur biologique
Louvet, Jean-Noël ULg

Doctoral thesis (2010)

This study examines the effect of erythromycin on activated sludge bacteria and the inhibition of the pollution removal in batch reactors treating urban wastewater. Results showed the importance of ... [more ▼]

This study examines the effect of erythromycin on activated sludge bacteria and the inhibition of the pollution removal in batch reactors treating urban wastewater. Results showed the importance of exposure time to erythromycin. Inhibition of nitrification and COD removal was measured during a 4 h period for erythromytcin concentrations higher than 1 mg/L. A 4 µg/L erythromycin concentration inhibited COD removal during a 20 h exposure time. The effect of erythromycin on nitrification was variable depending on the sludge origin. Erythromycin inhibited the specific nitrification rate with sludge from Nancy WWTP, but increased the nitrification rate at the other facility (Epinal WWTP). The cell lysis resulted in destruction of activated sludge flocs. Microscopic techniques (epifluorescence and confocal laser scanning microscopy (CLSM)), combined with a fluorescent viability indicator, allowed us to study erythromycin time-kill activity.Viability staining results showed a latency time before the lower antibiotic concentrations began to kill bacteria. This latency time could be related to antibiotic adsorption and diffusion into activated sludge flocs as well as the rate of bateria death. The effect of erythromycin according to the bacterial Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging combined with a Gram and Viability staining. Gram+ bacteria had a higher mortality rate than the Gram- bacteria. This result suggests that antibiotic in wastewater could change the activated sludge bacteria composition according to their Gram type by selecting bacteria the less sensitive to the antibiotics. [less ▲]

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See detailL’imagerie Confocale : un Outil Performant pour le Génie des Procédés Biologiques
Louvet, Jean-Noël ULg; Attik, Ghania; Hupont, Sébastien et al

Poster (2010)

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See detailWastewater treatment: effect of antibiotics on removal efficiency and a new approach to modeling transport, transfer, and reactions
Potier, Olivier; Louvet, Jean-Noël ULg; Le Moullec, Yann et al

Scientific conference (2010)

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See detailImplementation of micropollutant fate in wastewater treatment plant benchmark simulation models
Pons, Marie-Noëlle; Louvet, Jean-Noël ULg; Potier, Olivier

Conference (2010)

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See detailAdverse effects of antibiotics on activated sludge process: the erythromycin case
Louvet, Jean-Noël ULg; Attik, Ghania; Dumas, Dominique et al

Conference (2010)

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See detailAssessment of erythromycin toxicity on activated sludge via batch experiments and microscopic techniques (epifluorescence and CLSM)
Louvet, Jean-Noël ULg; Helouin, Yannick; Attik, Ghania et al

in Process Biochemistry (2010), 45

This study investigates erythromycin toxicity toward activated sludge as a function of exposure time and antibiotic concentration. Batch experiments were conducted and microscopic techniques ranging from ... [more ▼]

This study investigates erythromycin toxicity toward activated sludge as a function of exposure time and antibiotic concentration. Batch experiments were conducted and microscopic techniques ranging from bright-field microscopy to epifluorescence and confocal laser scanning microscopy (CLSM), combined with a fluorescent viability indicator (BacLight ® Bacterial Viability Kit, Molecular Probes), allowed us to study erythromycin time-kill activity. The erythromycin toxicity was observed at lower concentration when exposure time increased. A 4 .g/L erythromycin concentration was toxic to heterotrophic bacteria on a 5-day time exposure, and a 5 mg/L concentration inhibited nitrification. These findings are in agreement with the microscopic studies, which showed a latency time before the lower antibiotic concentrations began to kill bacteria. Microscope slide wells were used as micro-reactors in which erythromycin concentration ranged from 0.1 to 1 mg/L. After 45 min there were 94% (SD 3.8) of living bacteria in control micro-reactors, 67% (SD 3.1) in micro-reactors that contained 0.1 mg/L erythromycin and 37% (SD 18.6) in micro-reactors that contained 1 mg/L erythromycin. CLSM allowed visualization of isolated stained cells in the three-dimensional structure of damaged flocs [less ▲]

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See detailActivated sludge behaviour in a batch reactor in the presence of antibiotics: study of extracellular polymeric substances
Avella, Catalina; Essendoubi, M; Louvet, Jean-Noël ULg et al

in Water Science & Technology (2010)

The influence of Erythromycin, Roxithromycin, Amoxicillin, Tetracycline and Sulfamethoxazole on municipal sludge in batch reactors was investigated. The study was focused on extracellular polymeric ... [more ▼]

The influence of Erythromycin, Roxithromycin, Amoxicillin, Tetracycline and Sulfamethoxazole on municipal sludge in batch reactors was investigated. The study was focused on extracellular polymeric substances (EPS) as indicator of bacteria sensitivity to toxic agents. The EPS were analysed by UV-Vis and FT-IR spectroscopies and by size exclusion chromatography. It was found that Erythromycin and Roxithromycin induced a significant increase of bound EPS in flocs. This was attributed to a protection mechanism of the bacteria. Erythromycin was the only antibiotic which inhibited COD and nitrogen removal. [less ▲]

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See detailAdverse effects of erythromycin on the structure and chemistry of activated sludge
Louvet, Jean-Noël ULg; Giammarino, Cinzia; Potier, Olivier et al

in Environmental Pollution (2010), 158

This study examines the effects of erythromycin on activated sludge from two French urban wastewater treatment plants (WWTPs). Wastewater spiked with 10 mg/L erythromycin inhibited the specific evolution ... [more ▼]

This study examines the effects of erythromycin on activated sludge from two French urban wastewater treatment plants (WWTPs). Wastewater spiked with 10 mg/L erythromycin inhibited the specific evolution rate of chemical oxygen demand (COD) by 79% (standard deviation 34%) and the specific N–NH 4 þ evolution rate by 41% (standard deviation 25%). A temporary increase in COD and tryptophan-like fluorescence, as well as a decrease in suspended solids, were observed in reactors with wastewater containing erythromycin. The destruction of activated sludge flocs was monitored by automated image analysis. The effect of erythromycin on nitrification was variable depending on the sludge origin. Erythromycin inhibited the specific nitrification rate in sludge from one WWTP, but increased the nitrification rate at the other facility. [less ▲]

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