Fractionnement et caractérisation de la matière organique des lixiviats de décharges d'ordures ménagères

Les lixiviats de décharge constituent une source de nuisance qui vient s'ajouter aux nombreux problèmes de contamination du milieu environnant s'ils ne sont pas traités avant leur rejet. La matière organique, principale composante de ces effluents, doit retenir une grande attention dans la mesure où il est difficile d'éviter la propagation et la diffusion de cette pollution dans les sols et vers les nappes phréatiques. Cette étude vise à fractionner et à caractériser la matière organique présente dans des lixiviats de décharges d'ordures ménagères afin de prévoir et d'orienter le choix des traitements les plus adaptés compte tenu de leur biodégradabilité.La méthode de fractionnement utilisée comprend une adsorption spécifique sur résines macroporeuses Amberlite XAD (combinaison de XAD-7 et XAD-4) pour séparer les composés hydrophobes et hydrophiles qui sont ensuite extraits à la soude (composés acides) et au dichlorométhane (composés neutres). Le fractionnement de la matière organique par filtration sur résines XAD-7 et XAD-4, après une première étape de précipitation en milieu acide (pH=1), a permis de répartir l'ensemble des composés organiques du lixiviat dans six fractions de spécificités différentes fonction de la taille et/ou du caractère hydrophile ou hydrophobe des molécules. Les résultats montrent que ce protocole expérimental permet d'extraire au moins 98 % de la matière organique totale (pourcentage relatif aux teneurs de la demande chimique en oxygène ou DCO), dont la plus grande proportion est constituée des substances humiques (76 % à 90 % en DCO). Diverses méthodes analytiques ont été proposées en vue de caractériser les fractions isolées telles que l'analyse élémentaire, la spectrophotométrie infrarouge, la résonanoe magnétique nucléaire C13 (RMN Cl3) et la chromatographie CG/FID et CG/SM.Landfill leachates represent an obvious source of pollution for the environment and many studies have attempted to analyze organic pollutants found in leachates. A number of methods have been described in the literature for the isolation and concentration of dissolved organic matter from landfill leachate samples. Membrane ultrafiltration, gel permeation and high performance liquid chromatography are commonly used because these techniques can be easily adapted to separate soluble organic substances from large volumes of leachate. The objective of this study was to fractionate and characterize dissolved organic matter found in leachates collected from sanitary landfills.The discharges are defined with regard to the geological context from which they are situated and the nature of the waste. The discharges are classified in three categories, based upon the value of the permeability coefficient K, the substratum and its continuity.- class 1; impermeable site (K 10-[sup]6 ms-¹). The studied leachates come from landfill of class 2:- Crézin (Haute-Vienne) of compacted type: it was used for household rubbish and assimilated ordinary wastes. - Foussais-Payre (Vendée): leachate coming from the fermentation area of a composting plant and from the compost refuse. Fractionation of dissolved organic matter was applied on three leachates samples. The first sample was the raw leachate collected from the Crézin landfill and the two others came from Foussais-Payre (a raw sample and a sample treated in an aerated lagoon for 52 days). Because of the wide variety of organic compounds that can be found in such leachates, we classified and isolated the different groups of organic constituents using an XAD resin adsorption procedure. The experimental method consisted of acidifying samples to pH 1 to isolate the first fraction (fig. 1) and then treating the remaining supernatant with XAD-7 and XAD-4 resins. The adsorption on XAD resins allowed the isolation of the other organic fractions (figs. 2 to 6). Various analytical techniques were applied to characterize the isolated fractions such as elementary analysis infrared spectroscopy, ¹3C nuclear magnetic resonance (¹3C CP/MAS NMR), gas chromatography (GC/FID), and gas chromatography coupled to mass spectrometry (GC/MS). Results showed that more then 90% of the total organic carbon (TOC) in leachates can he recovered by the isolation procedure. Most of the isolated compounds corresponded to humic substances (76% to 90% of the chemical oxygen demand). Hydrophobic and hydrophilic neutral compounds were found only in small concentrations

Interleukin-1 Blockade in Systemic Juvenile Idiopathic Arthritis.

Systemic juvenile idiopathic arthritis (sJIA) is a severe disorder now linked more to autoinflammation than to autoimmunity. Clinical and laboratory evidence support the pathogenetic role of interleukin-1 (IL-1), and blockade of this cytokine has proved to be very effective in the treatment of sJIA. There are now several agents that block IL-1 available on the market. This article reviews the efficacy and safety of these drugs for the treatment of sJIA on the basis of published data, and offers the current view on treating sJIA according to its different phenotypes. There are no head to head trials among the different IL-1 inhibitors, and although efficacy has been demonstrated for all of them, it is still unknown which one would be more appropriate for which particular situation. The presence of synovitis in addition to active systemic features might be relevant for these choices. In addition, complications such as macrophage activation syndrome can be important since, on one hand, it has been associated with biologic therapy administration and, on another, there have been some reports of this complication being treated with anti-IL-1. Current recommendations by the American College of Rheumatology are now outdated, and new ones are being prepared. In the meantime, basic and clinical research is advancing in order to identify new treatment targets and to evaluate the different protocols currently in use

Experimental Investigation of a Pilot Solar-Assisted Permeate Gap Membrane Distillation

This research deals with the process of water desalination, involving an experimental design used to study a new prototype of a solar membrane distillation plant based on the weather conditions of Kairouan City, Tunisia. In this experiment, the pilot is left autonomous with the sun as the only source of energy. The operating process of a desalination plant consists of solar energy provided by the sun using solar energy collectors, which provide energy through their photovoltaic panels for heating brackish water. Additionally, the membrane used in this study was of the spiral wound design, which allowed for a compact arrangement besides effective internal heat recovery. The system start-up was successfully carried out and experimental studies were launched on various days of August 2020. During the experiment, the average production was approximately 15.92 L/m2 ap per day while the distillate’s electoral conductivity amounted to 1865 μS/cm. Calculations revealed that the specific thermal energy consumption for the system ranged between 90 and 310 kWh/m3

Disease evolution in systemic juvenile idiopathic arthritis: an international, observational cohort study through JIRcohort

Abstract Background Systemic juvenile idiopathic arthritis (systemic JIA) is a severe disease with both systemic and joint inflammation. This study aims to identify predictors of disease evolution within the systemic JIA population enrolled in the Juvenile Inflammatory Rheumatism cohort (JIRcohort). Methods Observational patient cohort study with 201 recruited children from 4 countries (3 European, 1 North Africa) from 2005 until 2019, using retrospectively (2005–2015) and prospectively (2015–2019) routine care collected data. Results Sixty-five patients with complete follow-up data for 24 months after first diagnosis were classified as monophasic (n = 23), polyphasic (n = 6) or persistent group (n = 36) corresponding to their evolution (unique flare, recurrent flares, or persistent disease activity respectively). The patients of the persistent group were more likely to have an earlier disease onset, before the age of 6 (OR 2.57, 95%-CI 0.70–9.46), persistence of arthritis at 12-months post-diagnosis (OR 4.45, 95%-CI 0.58–34.20) and higher use of synthetic DMARD (sDMARD, OR 5.28, 95%-CI 1.39–20.01). Other variables like global assessment by physician and by patient and C Reactive Protein levels at 12-months post-diagnosis were assessed but without any predictive value after adjusting for confounding factors. Conclusions Our results suggest that the earlier disease onset, the persistence of arthritis throughout the first year of disease evolution and the need of sDMARD might predict a persistent disease course

Additional file 1 of Disease evolution in systemic juvenile idiopathic arthritis: an international, observational cohort study through JIRcohort

Additional file 1: Supplementary Table 1. Clinical and laboratory features of patients with persistent vs non persistent disease evolution