Time filter

Source Type

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. Source

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. Source

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. Source

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. Source

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. Source

Discover hidden collaborations