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International audience; Monitoring the removal of organic micropollutants (OMPs) in advanced wastewater treatment facilities requires expensive and time-consuming analytical methods that cannot be installed online. Spectroscopic techniques such as fluorescence excitation/emission spectroscopy were demonstrated to offer the potential for monitoring OMPs removal in conventional wastewater treatment plants or ozonation pilots but their application to activated carbon (AC) adsorption processes was only investigated at lab scale and not in real treatment facilities. In this study, indexes from fluorescence emission/excitation matrices (EEMs) were used to find correlations with the removal of 28 OMPs from a large-scale AC pilot in fluidized bed employed for wastewater advanced treatment, as well as from batch experiments. Differences in OMPs removal could be observed depending on the operational conditions (i.e. pilot or batch experiments, contact time, type of AC) and the physico-chemical properties of the molecules. 7 PARAFAC components were derived from the fluorescence EEMs of 60 samples obtained before and after adsorption. Positive correlations were obtained between the removal of fluorescence indexes and most OMPs, and correlation coefficients were much higher than the ones obtained with UV254, confirming the interesting potential of fluorescence spectroscopy to accurately monitor adsorption performances at the industrial scale. The highest correlation coefficients were obtained for OMPs having the best removals while the ones that were refractory to adsorption, as well as to interactions with DOM, exhibited weak correlations. These results suggest that interactions between OMPs and fluorescing DOM and their subsequent co-adsorption onto AC were at the origin of the correlations found. Lower correlations were also found for the most biodegradable OMPs, which indicated that the occurrence of biological effects could make the monitoring of these compounds more challenging.

International audience; Highlights 17 • 7 commercial µGACs were characterized and tested with real wastewater 18 • A percentage of microporous volume higher than 65% reduced OMPs adsorption 19 • DOM reduced the adsorption of negatively-charged OMPs more than positive ones 20 • OMPs charge, hydrophobicity and minimal projection area influenced their adsorption 21 • The µGACs particle size had an impact on UV254 removal in continuous column tests 22 Graphical abstract 23 2 24 Abstract 25 Most studies dedicated to organic micropollutants (OMPs) removal from wastewater effluents by adsorption 26 onto activated carbon (AC) only consider a few conventional AC properties. The link between OMPs removal 27 and these properties is often missing, which limits the understanding of the adsorption process and the 28 interpretation of the results. The chemical, physical and textural properties of seven newly commercialized 29 micro-grain activated carbons (µGACs) were determined to assess their influence on the removal of 28 OMPs. 30 Conventional batch tests with wastewater effluent showed that a high percentage of microporous volume (> 31 65%) was detrimental for the removal of 10 OMPs, probably due to a higher blockage of micropores by 32 dissolved organic matter (DOM). The removal of 5 OMPs was correlated with µGACs surface chemistry 33 properties (i.e. charge) which were potentially modified by DOM adsorption or inorganic species, thus 34 favoring the adsorption of positively-charge compounds. A combination of OMPs properties including their 35 charge, hydrophobicity and minimal projection area could explain their removal. Correlations were found 36 between the removal of several OMPs and UV254 and dissolved organic carbon, suggesting that DOM and 37 OMPs interacted with each other or followed similar adsorption mechanisms. A decrease in µGACs particle 38 size had a positive impact on UV254 removal under continuous-flow conditions in columns representative of a 39 large-scale pilot due to better expansion. 40

International audience

National audience; Several advanced treatments such as activated carbon adsorption or ozonation are considered for micropollutants (MPs) removal in wastewater treatment plants (WWTPs). However, little information exists on the overall performances of a WWTP upgraded with those processes and the benefits provided regarding the elimination of multiple families of MPs. In this study, five sampling campaigns were conducted to determine the removal of 48 MPs (mainly pesticides and pharmaceutical residues) in a WWTP followed by a large-scale micro-grain activated carbon pilot with a treatment rate of 10 g/m3. The primary treatment had no effect on MPs (removal < 20%), while the biological treatment eliminated molecules that were sorbed onto sludges or biodegraded (> 60%). Without advanced treatment, the studied WWTP does not allow compliance with Swiss legislation on micropollutants, with reductions significantly lower than the 80% requested (< 50%) for 5 indicator substances If the additional elimination provided by the advanced treatment was not significant (< 10%) for MPs already well removed in the WWTP, activated carbon adsorption significantly reduces their concentration (e.g. decrease by a factor 100 for ibuprofen) and thus limits the impact of the WWTP on the receiving body. The additional elimination provided by the advanced treatment was significant (30-60%) for compounds recalcitrant to conventional treatments and overall removals higher than 60% were obtained for most MPs. A higher dose of activated carbon would be required to achieve higher removal, notably for MPs used in Switzerland as indicator substances. This study also provided the first data on the behavior of several molecules (acetamiprid, estrone, glyphosate, imidacloprid, lorazepam and ofloxacin) along a WWTP with an advanced treatment.; Plusieurs traitements avancés tels que l’adsorption sur charbon actif ou l’ozonation sont proposés pour le traitement des micropolluants (MP) au sein des stations de traitement des eaux usées (STEU). Cependant, peu d’informations existent sur les performances des STEU équipées de tels procédés et les bénéfices apportés au regard de l’élimination de multiples familles de MP. Dans cette étude, cinq campagnes d’échantillonnage ont été réalisées pour déterminer l’abattement de 48 MP (principalement des pesticides et des résidus pharmaceutiques) sur une STEU équipée d’un traitement avancé par adsorption sur charbon actif en micrograin en lit fluidisé avec un taux de traitement de 10 g/m3. Le traitement primaire n’a pas affecté la majorité des MP (abattement < 20 %), tandis que le traitement biologique a éliminé les molécules sorbées sur les boues ou biodégradées (> 60 %). Sans traitement avancé, la STEU étudiée ne permet pas de respecter la législation suisse sur les Mp, avec des abattements nettement inférieurs aux 80 % demandés (< 50 %) pour cinq substances indicatrices. Si l’élimination propre au traitement avancé n’a pas été significative (< 10 %) pour les MP déjà bien traités sur la STEU, l’adsorption sur charbon actif permet de diminuer de manière significative leur concentration (ex. : diminution d’un facteur 100 pour l’ibuprofène) et ainsi de limiter l’impact de la STEU sur le milieu récepteur. L’élimination propre au traitement avancé a été importante (30 à 60 %) pour les composés récalcitrants aux traitements conventionnels et permet d’atteindre des abattements globaux supérieurs à 60 % pour la majorité des MP. Une dose de charbon actif plus élevée serait nécessaire pour obtenir des abattements plus importants, notamment pour les MP utilisés en Suisse comme substances indicatrices. Cette étude a aussi permis de fournir les premières données sur le comportement de plusieurs molécules (acétamipride, estrone, glyphosate, imidaclopride, lorazépam et ofloxacine) le long d’une STEU équipée d’un traitement avancé.

International audience; Advanced processes for the removal of organic micropollutants (OMPs) from wastewater effluents include adsorption onto activated carbon, ozonation, or a combination of both processes. The removal of 28 OMPs present in a real wastewater effluent was studied by ozonation coupled to activated carbon adsorption and compared to a sole adsorption. The influence of the specific ozone dose (0.09–1.29 gO3/gDOC) and the influence of the powdered activated carbon (PAC) dose (2, 5 and 10 mg/L) were first studied separately. OMPs removal increased with both the specific ozone dose (up to 80% for a dose higher than 0.60 gO3/gDOC) and the PAC dose. Ozonation performances decreased in presence of suspended solids, which were converted to dissolved organic carbon. A correction of the specific ozone dose according to the suspended solids levels, in addition to nitrite, should be considered. The influence of ozonation (0.09, 0.22, 0.94 and 1.29 gO3/gDOC) on OMPs adsorption was then assessed. OMPs adsorption didn’t change at low specific ozone doses but increased at higher specific ozone doses due to a decrease in DOM adsorption and competition with OMPs. At low ozone doses followed by adsorption (0.22 gO3/gDOC and 10 mg/L PAC), the two processes appeared complementary as OMPs with a low reactivity toward ozone were well absorbed onto PAC while most OMPs refractory to adsorption were well eliminated by ozone. Improved removals were obtained for all compounds with these selected doses, reaching more than 80% removal for most OMPs while limiting the formation of bromate ion.

The authors would like to thank Céline Briand and Julien Pouillaude (SIAAP), Barbara Giroud (ISA) and Séverine Bareilles (Saur).; International audience; Several advanced treatments, such as ozonation or activated carbon adsorption, are currently considered for the removal of organic micropollutants (OMPs) in wastewater treatment plants (WWTP). However, little is known on the overall performances of a WWTP upgraded with those processes and the benefits provided regarding the elimination of multiple families of OMPs. In this study, 5 sampling campaigns were performed to determine the removal of 48 OMPs in a WWTP followed by an activated carbon pilot. The primary treatment had no effect on OMPs (removals 60%). The additional elimination provided by the advanced treatment was not significant (30%) for recalcitrant OMPs. Removals higher than 60% were obtained for all OMPs (except azithromycin and sulfamethoxazole) over the WWTP and the activated carbon pilot. The adsorption conditions (10 g/m3 fresh activated carbon addition) were not sufficient to achieve the 80% removal targeted in Switzerland for compounds suggested as indicator substances for wastewater treatment. A higher dose of activated carbon or the combination with another advanced treatment should be used to achieve a satisfactory removal of those compounds.

International audience; The presence of dissolved organic matter (DOM) in wastewater effluents is recognized as the main factor limiting the adsorption of organic micropollutants (OMPs) onto activated carbon. The degree of the negative effect that DOM, depending on its quality, exerts on OMPs adsorption is still unclear. The influence of the interactions between DOM and OMPs on their removal is also not fully understood. Adsorption isotherms and conventional batch tests were performed in ultra-pure water and in wastewater effluent to study the influence of DOM on the adsorption of 12 OMPs onto powdered activated carbon. Best fit of adsorption pseudo-isotherms was obtained with the Freundlich equation and showed, as expected, that OMPs adsorption was higher in ultra-pure water than in wastewater effluent due to the presence of DOM leading to pore blockage and competition for adsorption sites. LC-OCD analysis revealed that biopolymers and hydrophobic molecules were the most adsorbed fractions while humic acids were not removed after a contact time of either 30 min or 72 h. The presence of DOM had a negative impact on the removal of all OMPs after 30 min of adsorption, but similar removals to ultra-pure water were obtained for 6 OMPs after 72 h of adsorption. This demonstrated that competition between DOM and OMPs for adsorption sites was not a major mechanism as compared to pore blockage, which only slowed down the adsorption and did not prevent it. The charge of OMPs had a clear impact: the adsorption of negatively charged compounds was reduced in the presence of wastewater effluent due to repulsive electrostatic interactions with the adsorbed DOM and the PAC surface. On the other hand, the removal of positively charged compounds was improved. A 24 h pre-equilibrium between OMPs and DOM improved their removal onto PAC, which suggest that OMPs and DOM interacted in solution which decreased the negative effects caused by the presence of DOM, e.g. through co-adsorption of an OMP-DOM complex.

The authors gratefully acknowledge Céline Briand (SIAAP) for her technical assistance during the sampling campaigns and daily operation of the pilot system.; International audience; Among the release solutions for reducing the discharge of organic and persistent contaminants in the aquatic environment, the use of a tertiary treatment in addition to existing conventional wastewater treatment processes is considered. The use of micro-grain activated carbon in a fluidized bed is a promising technique investigated in this study. The effluents from a large-scale pilot system were analyzed by liquid chromatography coupled with high-resolution mass spectrometry (QToF). Several strategies were deployed, namely molecular fingerprint comparison, suspected and non-target analyses, identification of refractory compounds to treatment, and finally, quantification of identified compounds. The evaluation of the molecular fingerprints provided evidence of the overall effect of the tertiary treatment on the treated wastewater quality. The suspected approach highlighted the presence of 83 pharmaceuticals and pesticides as well as transformation products in the effluents. The non-target approaches also highlighted compounds refractory to tertiary treatment, such as illicit drugs or some pharmaceuticals. The identification and quantification of identified compounds underscored the suitability of micro-grain activated carbon in eliminating many classes of pharmaceuticals with various physicochemical properties, such as anti-hypertensive, analgesic, anti-viral, antidepressant and even various pesticides.

International audience; Background: The activated sludge treatments combined to the addition of ferric chloride is commonly used to eliminate nitrate and phosphate from waste water in urban area. These processes that need costly infrastructures are not suitable for rural areas and passive treatments (lagoons, reed bed filters…) are more frequently performed. Reed bed filters are efficient for removing organic matter but are not suitable for treating phosphate and nitrate as well. Passive water treatments using various materials (hydroxyapatite, slag…) were already performed, but those allowing the elimination of both nitrate and phosphate are not actually available.Methods: The goal of this work is to identify the most suitable iron based materials for such treatments and to determine their optimal use conditions, in particular in hydrodynamic mode. The reactivity of the iron based minerals was measured either by using free particles in suspension or by depositing these particles on a solid substrate.Results: Pozzolana, a volcanic rock, that is characterized by a porous sponge-like structure suits for settling a high amount of iron oxides. In addition, the experimental conditions enabling to avoid any ammonium formation when green rust encounters nitrate were also determined within the framework of a full factorial design. The dephosphatation and denitrification process is divided into two steps that will be performed inside two separated reactors. Indeed, the presence of phosphate inhibits the reduction of nitrate by green rust and the dephosphatation process must precede the denitrification process.Conclusion: In order to remove phosphate, ferrihydrite coated pozzolana is the best materials. The kinetics of reaction of green rust with nitrate is relatively slow and often leads to the formation of ammonium. In this process, it is interesting to favor the accumulation of nitrite in a first step, these species react much more quickly with green rust and do not transform into ammonium.

Le Syndicat interdepartemental pour l’assainissement de l’agglomeration parisienne (Siaap), via sa direction du developpement et prospective, a engage un projet de recherche (2013-2015) visant a etudier l’efficacite de differentes techniques de traitement tertiaire vis-a-vis des micropolluants emergents (residus medicamenteux, hormones, polluants de la directive cadre sur l’eau, etc.) encore presents dans les rejets de station d’epuration. Dans le cadre de ce projet, le procede CarboPlus, concu par la societe Stereau et base sur l’injection de charbon dans un reacteur a lit fluidise, est etudie en collaboration avec les equipes de la Saur et du Laboratoire eau, environnement et systemes urbains (Leesu). Les differentes campagnes de mesure ont montre que ce procede permettait d’eliminer efficacement les principaux composes suivis. Le niveau d’abattement est directement lie au taux de traitement, c’est-adire a la quantite de charbon actif en poudre (CAP) neuf injecte en continu dans le reacteur. L’application d’un taux de traitement de 10 g/m3 est suffisante pour eliminer efficacement un grand nombre de composes; huit composes etant abattus a plus de 80% avec ce taux de traitement. L’augmentation de ce dernier jusqu’a 20 g/m 3 permet d’augmenter encore l’efficacite du traitement. En passant d’un taux de traitement de 10 a 20 g/m 3 , le nombre de composes abattus a plus de 80% passe a une quinzaine. Le gain est particulierement important pour certains micropolluants : ketoprofene, naproxene, ofloxacine, sulfadiazine ou sulfamethoxazole, diclofenac; cette derniere molecule etant eliminee a 90% avec ce taux de traitement.

International audience; In this study, ageing characteristics of an industrial hollow-fiber membrane module were investigated after 50 months of drinking water production. For this purpose, the industrial module was opened to make 18 smaller modules with hollow-fibers taken from different parts of the industrial module. These modules were probed by the use of a magnetic nanoparticle (NP) challenge test based on magnetic susceptibility (K) measurement of permeate. No magnetic susceptibility was detected in permeate when the challenge test was performed on an intact membrane module, indicating the complete retention of nanoparticles by the membrane. The compromised membrane module can be successfully detected by means of magnetic susceptibility measurement in permeate. So, this study clearly demonstrates that ageing of ultrafiltration membranes can be monitored by measuring the magnetic susceptibility of permeate from an ultrafiltration membrane module. These results showed that the hollow fibers in the center zones of the bundle would age faster than those in the outer zones around the bundle. This result is in agreement with numerical simulation (Daurelle et al. 2011).

En France, et ce principalement pour des raisons economiques, la methanisation des boues d’epuration est encore peu appliquee dans les stations de petite et moyenne capacite. Pour ameliorer le bilan economique de la digestion anaerobie des boues d’epuration dans ce type de station, il est possible de completer les alimentations du digesteur par d’autres substrats organiques a plus fort potentiel energetique et deja presents sur le territoire. Quels sont les impacts de tels procedes et comment optimiser leur integration dans la filiere de traitement des eaux ?