Time filter

Source Type

Mousset E.,University Paris Est Creteil | Oturan N.,University Paris Est Creteil | van Hullebusch E.D.,University Paris Est Creteil | Guibaud G.,CNRS Research Group on Water, Soil and Environment | And 2 more authors.
Water Research | Year: 2014

One of the aims in soil washing treatment is to reuse the extracting agent and to remove the pollutant in the meantime. Thus, electro-Fenton (EF) degradation of synthetic soil washing solutions heavily loaded with phenanthrene was suggested for the first time. Two solubilising agents hydroxypropyl-beta-cyclodextrin (HPCD) and Tween 80® (TW 80) were chosen as cyclodextrin (CD) and surfactant representatives, respectively. In order to reuse HPCD and to degrade the pollutant simultaneously, the following optimal parameters were determined: [Fe2+]=0.05mM (catalyst), I=2000mA, and natural solution pH (around 6), without any adjustment. Only 50% of TW 80 (still higher than the critical micelle concentration (CMC)) can be reused against 90% in the case of HPCD while phenanthrene is completely degraded in the meantime, after only 180min of treatment. This can be explained by the ternary complex formation (Fe2+-HPCD-organic pollutant) (equilibrium constant K=56mM-1) that allows OH to directly degrade the contaminant. This confirms that Fe2+ plays an important role as a catalyst since it can promote formation of hydroxyl radicals near the pollutant and minimize HPCD degradation. After 2h of treatment, HPCD/phenanthrene solution got better biodegradability (BOD5/COD=0.1) and lower toxicity (80% inhibition of luminescence of Vibrio fischeri bacteria) than TW 80/phenanthrene (BOD5/COD=0.08; 99% inhibition of V. fischeri bacteria). According to these data, HPCD employed in this integrated (soil washing+EF degradation) approach gave promising results in order to be reused whereas the pollutant is degraded in the meanwhile. © 2013 Elsevier Ltd.


Nicolau R.,University of Toulon | Nicolau R.,CNRS Research Group on Water, Soil and Environment | Lucas Y.,University of Toulon | Merdy P.,University of Toulon | Raynaud M.,University of Toulon
Water Research | Year: 2012

Base flow and storm flow events from a small, urbanized Mediterranean river located in the South of France were studied to evaluate net fluxes from the continent to the coastal sea water. Considered variables were: pH, conductivity, redox potential, temperature, dissolved O2, SPM (Suspended Particulate Matter), Cl-, NO3-, SO42-, Na+, K+, Mg2+, Ca2+, DOC (Dissolved Organic Carbon), Cu, Zn, Cd and Pb in the dissolved fraction and POC (Particulate Organic Carbon), Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the particulate fraction. If rainfall intensity and antecedent rainfall history were sufficient to explain many observed variations, the patterns of particles and solutes transport greatly varied from one storm event to another. SPM, POC, particulate Cu, Zn, Cd and Pb had similar behavior characterized by an immediate increase at the beginning of the storm flow and the highest values at the first high discharge peak. Among dissolved species, Cl-, SO42-, Na+, Ca2+ and Mg2+ had a behavior very similar one to the other. They exhibited high concentrations and enrichment factors at the beginning of the storm flow, due to fast leaching of highly labile species. Their concentrations decreased during posterior discharge peaks but positive enrichment factors indicated permanent sources for these ions. DOC, K+ and NO3- had different behaviors which indicated sources positively correlated with rainfall intensity. A 3D-fluorescence study showed that the humified organic matter contribution to DOC increased during storm flow. Relationships between DOC and dissolved Cu and Pb indicated differences in organic-matter binding properties between dry and humid periods. Storm flow were responsible for more than 90% of the annual output to the sea of SPM, POC and particulate Cu, Zn, Cd and Pb and more than 70% for dissolved Pb, Cd, NO3- and DOC. For the other dissolved species, outputs were balanced between base flow and storm flow. Contrary to what was observed in large rivers, organic carbon was mainly transported in the POC fraction. The average specific fluxes of Cu and Pb to the sea were 3.8 and 3.4 kg km-2 y-1, respectively, of the same order of magnitude than specific fluxes of other North-Mediterranean rivers, but outputs were more intense during shorter durations. The extrapolation of the Eygoutier River data to the Mediterranean non-desert coastline showed that the order of magnitude of Cu and Pb annually brought to the sea by the whole of small anthropized coastal rivers can be similar to the annual input by the Rhône or the Po River. © 2012 Elsevier Ltd.


Labanowski J.,University of Poitiers | Pallier V.,CNRS Research Group on Water, Soil and Environment | Feuillade-Cathalifaud G.,CNRS Research Group on Water, Soil and Environment
Journal of Hazardous Materials | Year: 2010

Organic matter contained in leachates appears to be a relevant indicator of waste evolution. Among the physico-chemical treatments applied to stabilize leachates, coagulation-flocculation is considered a classical process and electrocoagulation can be developed. Electrocoagulation tests were carried out in a laboratory pilot using aluminium plates and compared to classical coagulation-floculation with aluminium ions and to electrolysis alone. The leachate used in this study came from the landfill of Crezin (Limoges, France) and it presented low biodegradability and high concentration of macromolecules. To assess the efficiency of the chemical and electrochemical processes, we specifically studied Organic Matter (OM) by using two protocols: adsorption on XAD resins and fractionation by ultrafiltration. Biodegradable Dissolved Organic Carbon (BDOC) measurements were applied to the fractions extracted by XAD resins and were also used as an indicator of the efficiency of the treatments. Residual organic matter concentration was the same for the two processes but its composition appeared different after electrocoagulation: a higher percentage of small hydrophilic organic molecules which seemed to be less biodegradable than the initial organic matter was observed. © 2010 Elsevier B.V.


Labanowski J.,University of Poitiers | Feuillade G.,CNRS Research Group on Water, Soil and Environment
Water Research | Year: 2011

This study concerns the possible changes in the repartition and the molecular characteristics of hydrophilic substances (HyS) isolated by XAD resins from the same source of organic matter as a function of the distribution coefficient k' and the DOM concentration. We tested that on two different sources of organic matter (a surface water and a landfill leachate). Breakthrough curves column experiments highlighted a modification of the repartition between hydrophilic and humic substances according to the k' value applied. But, we find that the composition of HyS is significantly modified between k' = 50 and 100. Our observations tend to suggest a higher contribution of humic-like matter (high-molecular weight aromatic compounds) with an increase of the k' value. This results in a shift of fluorescence bands to longer wavelengths and changing patterns of the SEC profiles and molecular fingerprints performed by flash pyrolysis. Our results show that DOM concentration also influences the composition of HyS while little effect is observed on their quantification at k' = 50 or 100. © 2010 Elsevier Ltd.


Salsabil M.R.,Mashad High Education and Research Institute | Laurent J.,CNRS Research Group on Water, Soil and Environment | Casellas M.,CNRS Research Group on Water, Soil and Environment | Dagot C.,CNRS Research Group on Water, Soil and Environment
Journal of Hazardous Materials | Year: 2010

Aerobic and anaerobic digestions were compared with different sludge reduction processes such as ultrasonic, ozone, and thermal treatments. Each treatment was tested under the following conditions to improve batch aerobic or anaerobic digestion: ultrasound (200,000 kJ kgT S0 - 1), thermal (40 °C, 60 °C, 90 °C for 90 min, 120 °C 15 min, 1 bar), and ozonation (0.1 g O3 gT S0 - 1). The different pretreatments induced organic matter solubilisation and intrinsic sludge reduction (total suspended solids): ultrasound (47%), thermal 90 °C (16%), ozone (15%), thermal 60 °C (9%), thermal 40 °C (5%), autoclave (120 °C) (4.2%). TSS (and also VSS) solubilisation were found to be highly correlated to the pretreatment ability to break the flocs rather than to specific energy input. The total values of TSS reduction ranged from 57% to 71% under aerobic conditions and from 66% to 86% under anaerobic conditions. TSS solubilisation after pretreatment can be considered as a predictive parameter of sludge volume reduction enhancement after aerobic or anaerobic digestion while specific energy input did not show anything or negligible impact. In our experimental conditions, ultrasound and ozone led to the best TSS removal improvement after both aerobic (30% and 20%) and anaerobic digestion (20%). Ultrasonic and ozone pretreatments prior to aerobic or anaerobic digestion led to the best reduction of the specific energy required for removing 1 kg of TSS compared to the control. Anaerobic digestion was globally more effective (compare to aerobic digestion) in enhancing sludge production reduction. © 2009 Elsevier B.V. All rights reserved.


Bourven I.,CNRS Research Group on Water, Soil and Environment | Costa G.,CNRS Chemistry of Natural Substances Laboratory | Guibaud G.,CNRS Research Group on Water, Soil and Environment
Bioresource Technology | Year: 2012

Exopolymeric substances (EPS) were extracted by EDTA from activated and anaerobic granular sludge. Due to the presence of EDTA in EPS extract, interferences were pointed out for the characterization of EPS by means of the colorimetric methods and fluorescence spectroscopy. Other methods have been investigated to characterize the EPS protein fraction. Size exclusion chromatography (SEC), performed at a fluorescence excitation-emission matrix of 221/360. nm (tryptophan protein-like substances) for detection, was suitable and allowed obtaining a fingerprint of the protein-like substance fractions and determining apparent molecular weight (MW). Polyacrylamide gel electrophoresis (PAGE) was performed under either native or denaturing conditions. Various staining applications after EPS migration are effective in obtaining a protein (silver staining) or glycoprotein (PAS staining) fingerprint or MW distribution. SEC and PAGE are both appropriate techniques for the qualitative characterization of protein fractions from EPS extracted by EDTA and moreover differentiate EPS according to sludge origin and type. © 2011 Elsevier Ltd.


Bourven I.,CNRS Research Group on Water, Soil and Environment | Joussein E.,CNRS Research Group on Water, Soil and Environment | Guibaud G.,CNRS Research Group on Water, Soil and Environment
Bioresource Technology | Year: 2011

This work characterises the mineral fraction of EPS extracts obtained using eight different methods from two activated sludges by total mineral content determination, Fourier Transformed Infrared spectrometry and with scanning electron microscopy coupled with an EDX probe. Despite EPS dialysis, the EPS extracts displayed a mineral fraction between 2% and 40% of the EPS dry weight depending on the extraction method used. The main mineral elements found in the EPS extract were Ca, Mg, Na, K, Al, Fe, Mn, P, Si and S, but their contents were strongly affected by the extraction method used. Some of the minerals are associated with the organic molecules within the EPS. The presence of mineral particles of various compositions and structures (clays, quartz or carbonate) in the EPS extract with a wide range in size was clearly demonstrated. Moreover, the association of metallic elements with the mineral particles in the EPS extract was highlighted. © 2011 Elsevier Ltd.


Delmail D.,CNRS Research Group on Water, Soil and Environment
Nordic Journal of Botany | Year: 2010

Muhlenbergia fasciculata T. P. I. Phan, originally described in 1994, was an invalidly published name, because two collections (one flowering, one fruiting) were designated as the type. The name is validated here, with the flowering specimen designated as the holotype. © 2010 The Authors.


Pallier V.,CNRS Research Group on Water, Soil and Environment | Feuillade-Cathalifaud G.,CNRS Research Group on Water, Soil and Environment | Serpaud B.,CNRS Research Group on Water, Soil and Environment
Chemosphere | Year: 2011

The aim of this study is to evaluate and understand the electrocoagulation/flocculation (ECF) process to remove arsenic from both model and natural waters with low mineral content and to compare its performances to the coagulation/flocculation (CF) process already optimized. Experiments were thus conducted with iron electrodes in the same specific treatment conditions (4≤current density (mAcm-2)≤33) to study the influence of organic matter on arsenic removal in conditions avoiding the oxidation step usually required to improve As(III) removal. The process performance was evaluated by combining quantification of arsenic residual concentrations and speciation and dissolved organic carbon residual concentrations with zeta potential and turbidity measurements. When compared to CF, ECF presented several disadvantages: (i) lower As(V) removal yield because of the ferrous iron dissolved from the anode and the subsequent negative zeta potential of the colloidal suspension, (ii) higher residual DOC concentrations because of the fractionation of high molecular weight compounds during the treatment leading to compounds less prone to coagulate and (iii) higher residual turbidities because of the charge neutralization mechanisms involved. However, during this process, As(III) was oxidized to As(V) improving considerably its removal whatever the matrix conditions. ECF thus allowed to improve As(III) removal without applying an oxidation step that could potentially lead to the formation of toxic oxidation by-products. © 2011 Elsevier Ltd.


Hadjoudja S.,CNRS Research Group on Water, Soil and Environment | Deluchat V.,CNRS Research Group on Water, Soil and Environment | Baudu M.,CNRS Research Group on Water, Soil and Environment
Journal of Colloid and Interface Science | Year: 2010

According to previous studies, Microcystis aeruginosa, a picocyanobacteria, is more sensitive to copper than the other phytoplanktonic species such as Chlorella vulgaris a chlorophycea. An experimental study was carried out to determine the cell wall characteristics of both species. The cell surface of M. aeruginosa presented a lower hydrophobic character and a more negative surface charge over a larger pH range than for C. vulgaris, according to hydrophobicity and zeta potentials measurements. By combining infrared spectroscopy data and potentiometric titrations, the total concentration of functional groups determined for M. aeruginosa (1.60 × 10-3 mol/g), as well as the number of carboxyl groups, was higher than for the C. vulgaris ones (0.22 × 10-3 mol/g). The differences in surface properties, as shown by chemical, physicochemical and spectroscopic measurements would justify the differences in sensitivities to copper ions up-take between the two specimens. © 2009 Elsevier Inc. All rights reserved.

Loading CNRS Research Group on Water, Soil and Environment collaborators
Loading CNRS Research Group on Water, Soil and Environment collaborators