Présence et devenir des médicaments dans les eaux usées urbaines, une analyse bibliographique

Depuis quelques années, la présence de substances pharmaceutiques a été observée dans les milieux aquatiques y compris dans l’eau potable. Les principales sources de dispersion de ces composés dans l’environnement sont les stations d’épuration des eaux usées (STEP). Une analyse de la littérature publiée sur le sujet est proposée. Ce sont les analgésiques/anti-inflammatoires, les hypocholestérolémiants, les cytostatiques et les bêta-bloquants qui présentent les concentrations les plus élevées en entrée de station d’épuration. Malgré des rendements d’élimination quelquefois très élevés, les concentrations de ces groupes de médicaments restent non négligeables dans les effluents de stations.Les antibiotiques forment un des plus importants groupes de médicaments à cause de leur niveau de consommation, de leur fréquence de détection dans les milieux aquatiques et de leur action spécifique sur les bactéries, notamment celle potentiellement néfaste qu’ils peuvent avoir sur les bactéries mises en oeuvre dans les systèmes de traitement biologique des eaux résiduaires urbaines. Globalement, la charge en antibiotiques est faible dans les eaux usées urbaines mais elle est forte dans les effluents des hôpitaux. Les rendements d’élimination sont, quant à eux très variables, allant de 0 % pour le nitrothiazole à 95 % pour la tétracycline.For several years, the occurrence of pharmaceutical substances in the aquatic environment, and even in drinking water, has been a source of concern. The main sources of dispersion of these substances are wastewater treatment plants (WWTP). An analysis of the available literature on this topic is proposed. Analgesic, anti-inflammatory, anti-cholesterol and cytostatic drugs as well as beta-blockers are the substances that can be found in the highest concentrations in plant influents. In spite of elimination yields that can be very high, their concentrations in plant effluents can remain non-negligible. Antibiotics are one of the most important drug classes, due to their large consumption, their prevalence in aquatic systems and their specific action on bacteria, especially on those used in urban wastewater treatment biosystems. Globally, antibiotic concentrations in urban wastewater are normally low but they can be high in hospital wastewater. Elimination yields are very variable, ranging from a low of 0% for nitrothiazole to 95% for tetracycline

Investigating the Efficiency of Functionalized PAMAM-GO Nano-Composite for Nitrate Removal from Aqua Solutions

Due to the high solubility of nitrate in water, conventional treatment methods fail to remove it. This research investigated for the first time in national and global level, the efficiency of functionalized PAMAM-Go nanocomposite for nitrate removal from aquatic solutions. GO was synthesized by modified Hummers method. AFM images were used to characterize the GO and the AGO. Experiments were performed in a batch reactor and the main factors of pH, reaction time, and concentration of PAMAM_GO were investigated. The highest removal efficiency was obtained as 84% at 5 mL/L functionalized PAMAM_GO, pH of 3 and 25 min reaction time. The results showed that nitrate removal by functionalized PAMAM-Go nanocomposite is directly correlated with nanocomposite concentration and contact time while it is inversely correlated with pH and initial concentration of nitrate. It seems that ion exchange between nitrate and chloride is the main mechanism of nitrate removal by functionalized PAMAM_GO nano composite according to functionalization of PAMAM-Go using hydrochloric acid. This method can be used as a suitable method for in situ treatment of nitrate and many  pollutants in water and wastewater, due to its easy operation, no need for high levels of expertise and sophisticated equipment, no need for large space of construction, low initial investment, low price, availability of raw materials, simple synthesis of graphene oxide and  easy  to functionalize

Efficiency Evaluation of Nitrate Removal from Synthetic Solutions by Dendrimer- Graphene Oxide Nano-Composite Activated with HCl

High soluability of nitrate ions in water cause the dysfunction of many existing treatment methods in the removal of this very dangerous ion from aqueous media. On the other hand,  due to the need for in situ treatment methods, in particular for groundwater, the replacement of old inefficient methods with new compounds is required. In this study, for the first time, the efficiency of activated dendrimer- graphene oxide for nitrate removal from an aquatic solution was investigated. Experiments were performed in a batch reactor and the main factors of pH, reaction time, and concentration of PAMAM-GO were investigated. The highest removal efficiency was obtained as 90% at 0.025mg/L activated dendrimer- graphene oxide, pH of 7.5 and 15 min reaction time. The results showed that nitrate removal by activated dendrimer-graphene oxide is correlated with nanocomposite concentration, contact time, pH and initial concentration of nitrate. It seems that ion exchange between nitrate and chloride is the main mechanism of nitrate removal by activated dendrimer-graphene oxide according to functionalization of activated dendrimer-graphene oxide using hydrochloric acid. This method can be used as a suitable method for in situ removal of nitrate from water and wastewater due to the desirable ability of the nanocomposite and its optimal compatibility with the environment

Investigation of concentration polarization in a cross-flow nanofiltration membrane: Experiment and CFD modelling

Numerous researches have been investigated on the mass transfer phenomena and hydrodynamics for the fluid in the vicinity of the membrane surface by the mathematical modelling and simulation. Due to complexities involved in solving transport phenomena within membranes, the application of CFD simulation study for determining the concentration polarization (CP) profile in the membrane channel is limited. In this study, a 2D CFD modelling and simulation of CP phenomena in nanofiltration of an aqueous solution of MgSO47H2O in a vertical spacer-filled flat sheet membrane module was presented. A response surface methodology (RSM) statistical analysis has been designed in order to fully capture effects of variations of the feed liquid flow and the transmembrane pressure (TMP) on the permeate flux and concentration. It was also shown that increasing TMP or the liquid flow rate led to enhancing the permeate flux while increasing the feed concentration decreased it. The simulated results were validated and compared with the available experimental data, showing a satisfactory agreement. Eventually, the mass transfer coefficient derived from CFD simulations and calculated from Sherwood empirical relationships were compared which showed 10% and 33% difference in lower and higher liquid flow rates, respectively

Pharmaceutical substances and urban wastewater. I, Literature survey. II, Effect of two macrolide antibiotics on activated sludge

Les principaux points de dispersion des composés pharmaceutiques dans l’environnement sont les stations d’épuration des eaux usées. A partir de l’analyse de la base de données constituée au cours de ce travail, les quantités de ces composés trouvées dans ces installations peuvent être directement liées à celles de médicaments consommés. La situation, quant à leur élimination de la phase liquide, est contrastée. Ainsi certaines hormones sont éliminées avec des rendements importants mais d’autres ne le sont pas du tout. Les produits radio-contrastants à base d’halogènes et notamment d’iode, soupçonnés d’être cancérogènes, sont majoritairement non biodégradables. Les effets d’antibiotiques sur les boues activées ont été plus particulièrement étudiés du fait de leur consommation, de leur présence dans les milieux aquatiques et de leur action spécifique sur les bactéries. Des expériences permettant d’évaluer la toxicité de ces principes actifs ont été conduites sur des boues activées en réacteur discontinu, avec un suivi de la morphologie des flocs par analyse d’images de microscopie optique. Il a été ainsi observé que, selon la concentration utilisée, l’érythromycine et la tylosine, macrolides largement utilisés respectivement en médecine humaine et vétérinaire, inhibent l’élimination de la pollution organique et dégradent l’ensemble de la biomasse. Ces antibiotiques ont également un effet néfaste sur le métabolisme de l’azote, qu’il s’agisse de l’ammonification, de la nitritation et de la nitratationThe main sources of dispersion of pharmaceutical substances in environment are wastewater treatment plants. Based on the analysis of the database built during this project, the amounts of pharmaceutical substances found in plants can be directly related to the amount consumed. Regarding their elimination from the liquid phase, the situation is very disparate. The elimination yield of hormones can be null or very large. Halogen-based X-ray contrast media (or AOX) are mainly non biodegradable. The effects of antibiotics on activated sludge have been especially investigated due to their consumption, presence in aquatic environment and specific action on bacteria. Batch tests have been performed to evaluate the toxicity of these active pharmaceutical ingredients on activated sludge. Sludge morphology was monitored by analysis of light microscopy images. Depending upon the applied dose, erythromycin and tylosin, two macrolides widely used for human and animal health care, inhibit the elimination of organic pollution and damage biomass. These antibiotics have a deleterious effect on ammonification, nitritation and nitratatio

Composés pharmaceutiques et eaux usées urbaines. I, Analyse bibliographique. II, Effet de deux antibiotiques de type macrolide sur les boues activées

The main sources of dispersion of pharmaceutical substances in environment are wastewater treatment plants. Based on the analysis of the database built during this project, the amounts of pharmaceutical substances found in plants can be directly related to the amount consumed. Regarding their elimination from the liquid phase, the situation is very disparate. The elimination yield of hormones can be null or very large. Halogen-based X-ray contrast media (or AOX) are mainly non biodegradable. The effects of antibiotics on activated sludge have been especially investigated due to their consumption, presence in aquatic environment and specific action on bacteria. Batch tests have been performed to evaluate the toxicity of these active pharmaceutical ingredients on activated sludge. Sludge morphology was monitored by analysis of light microscopy images. Depending upon the applied dose, erythromycin and tylosin, two macrolides widely used for human and animal health care, inhibit the elimination of organic pollution and damage biomass. These antibiotics have a deleterious effect on ammonification, nitritation and nitratationLes principaux points de dispersion des composés pharmaceutiques dans l'environnement sont les stations d'épuration des eaux usées. A partir de l'analyse de la base de données constituée au cours de ce travail, les quantités de ces composés trouvées dans ces installations peuvent être directement liées à celles de médicaments consommés. La situation, quant à leur élimination de la phase liquide, est contrastée. Ainsi certaines hormones sont éliminées avec des rendements importants mais d'autres ne le sont pas du tout. Les produits radio-contrastants à base d'halogènes et notamment d'iode, soupçonnés d'être cancérogènes, sont majoritairement non biodégradables. Les effets d'antibiotiques sur les boues activées ont été plus particulièrement étudiés du fait de leur consommation, de leur présence dans les milieux aquatiques et de leur action spécifique sur les bactéries. Des expériences permettant d'évaluer la toxicité de ces principes actifs ont été conduites sur des boues activées en réacteur discontinu, avec un suivi de la morphologie des flocs par analyse d'images de microscopie optique. Il a été ainsi observé que, selon la concentration utilisée, l'érythromycine et la tylosine, macrolides largement utilisés respectivement en médecine humaine et vétérinaire, inhibent l'élimination de la pollution organique et dégradent l'ensemble de la biomasse. Ces antibiotiques ont également un effet néfaste sur le métabolisme de l'azote, qu'il s'agisse de l'ammonification, de la nitritation et de la nitratatio

Composés pharmaceutiques et eaux usées urbaines. I, Analyse bibliographique. II, Effet de deux antibiotiques de type macrolide sur les boues activées

Les principaux points de dispersion des composés pharmaceutiques dans l environnement sont les stations d épuration des eaux usées. A partir de l analyse de la base de données constituée au cours de ce travail, les quantités de ces composés trouvées dans ces installations peuvent être directement liées à celles de médicaments consommés. La situation, quant à leur élimination de la phase liquide, est contrastée. Ainsi certaines hormones sont éliminées avec des rendements importants mais d autres ne le sont pas du tout. Les produits radio-contrastants à base d halogènes et notamment d iode, soupçonnés d être cancérogènes, sont majoritairement non biodégradables. Les effets d antibiotiques sur les boues activées ont été plus particulièrement étudiés du fait de leur consommation, de leur présence dans les milieux aquatiques et de leur action spécifique sur les bactéries. Des expériences permettant d évaluer la toxicité de ces principes actifs ont été conduites sur des boues activées en réacteur discontinu, avec un suivi de la morphologie des flocs par analyse d images de microscopie optique. Il a été ainsi observé que, selon la concentration utilisée, l érythromycine et la tylosine, macrolides largement utilisés respectivement en médecine humaine et vétérinaire, inhibent l élimination de la pollution organique et dégradent l ensemble de la biomasse. Ces antibiotiques ont également un effet néfaste sur le métabolisme de l azote, qu il s agisse de l ammonification, de la nitritation et de la nitratationThe main sources of dispersion of pharmaceutical substances in environment are wastewater treatment plants. Based on the analysis of the database built during this project, the amounts of pharmaceutical substances found in plants can be directly related to the amount consumed. Regarding their elimination from the liquid phase, the situation is very disparate. The elimination yield of hormones can be null or very large. Halogen-based X-ray contrast media (or AOX) are mainly non biodegradable. The effects of antibiotics on activated sludge have been especially investigated due to their consumption, presence in aquatic environment and specific action on bacteria. Batch tests have been performed to evaluate the toxicity of these active pharmaceutical ingredients on activated sludge. Sludge morphology was monitored by analysis of light microscopy images. Depending upon the applied dose, erythromycin and tylosin, two macrolides widely used for human and animal health care, inhibit the elimination of organic pollution and damage biomass. These antibiotics have a deleterious effect on ammonification, nitritation and nitratationNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Application of Froude dynamic similitude in anaerobic baffled reactors to prediction of hydrodynamic characteristics of a prototype reactor using a model reactor

An anaerobic baffled reactor is a system developed in recent decades and has been used as part of the treatment of high-strength wastewater. Since the function of this system is based on its hydrodynamic features, hydrodynamics and the regime of the flow through the reactor are crucial. In this study, a prototype reactor with eight chambers, which had a total volume of 48 L, and a model reactor, whose dimensions were half of those of the prototype reactor, were used. The Froude dynamic similitude in these reactors was investigated. The results show that the curve dimensionless variances were 0.089 and 0.096 for the prototype and model reactors, respectively, the short-circuiting indices were 0.483 and 0.489 for the prototype and model reactors, respectively, the effective volume and short-circuiting index measurement errors were both 1%, the hydraulic efficiency error was 2%, and the Peclet and dispersion number errors were both 7%. Most of the compared indices were close to one another in value. Therefore, the model reactor can be used based on the Froude dynamic similitude to determine hydrodynamic characteristics of a baffled reactor at a full scale

Water Pollutants Adsorption through an Enhanced Activated Carbon Derived from Agriculture Waste

Background & Aims of the Study: A high nitrate and arsenic concentration in water resources represent a potential risk to the environment and public health. The present work improved a chemo-physically modified activated carbon derived from walnut shells as an adsorbent to improve nitrate and arsenic removal ability from water. Materials & Methods: To increase removal efficiency, activated carbon surface characteristics were improved by acidification. Chemical activation was achieved when the carbon was mixed with water and 5% (v/v) phosphoric acid. After adsorbent preparation, the contact time, pH and the initial concentration were studied as variables. Results:  The effective pH for adsorption onto activated carbon was 6.5. The results indicated that 70 s and 3 mins was the sufficient time to attain equilibrium for a maximum removal efficiency of 78.44% and 98% for nitrate and arsenic, respectively. The adsorption capacity of the adsorbent was 10.60 mg nitrate/g carbon and 120 μg arsenic/g carbon. Removal obeyed the Langmuir isotherm and pseudo-second-order kinetic model. Conclusion: The results showed a noticeable improvement in activated walnut-shell carbon absorbance (improvement in crystalline structure, chemical bonds, and morphology of micropores) by chemo-physical activation. Chemo-physical activation increased the surface area of the adsorbent from 1067 to 1437 m2g‒1 and decreased the mean pore size from 3.28 to 2.08 nm. The characterization results showed the major reasons of adsorption could be structure, size and distributions of pores, high surface area and chemical bonds

Activation of Graphene Oxide with Hydrochloric Acid for Nitrate Removal from Aqueous Solutions

Long-term drinking of nitrate-contaminated water poses a serious risk to human health. The present study explores the possibility of enhancing the adsorption capacity of graphene oxide via activation with hydrochloric acid for nitrate removal from aqueous solutions. Experiments were performed in a batch reactor in which such major factors as pH, reaction time, and concentrations of both graphene oxide (GO) and activated graphene oxide (AGO) were used as variables. Nitrate removal efficiency was investigated using the One-Way ANOVA statistical test and SPSS-16 software. The chemical composition and solid structure of the synthesized AGO were analyzed using FE-SEM coupled with energy dispersive spectrometry (EDS). The micropore volumes of the samples were determined using the BET and BJH. The predominant composition (52%) of the synthesized AGO was C and its mean pore diameter was 26.896 nm. The maximum adsorption capacity of AGO was estimated at 3333.33 mg/g. Based on the results, the AGO nano-structure may be recomended as a new means for nitrate removal from aqueous solutions