Etude de la dépollution des sols par extraction sous pression réduite. application au traitement des COV

L\u27extraction sous pression réduite est l\u27une des techniques de dépollution envisageables lorsqu\u27il y a contamination d\u27un sol par des composés organiques volatils (COVs). Cette technique consiste à créer une dépression dans le sol et induire un écoulement contrôlé d\u27air qui entraînera les contaminants volatils dans la phase gazeuse extraite. Les objectifs de ce travail peuvent se résumer de la façon suivante : - caractérisation de la méthode la plus adaptée à déterminer les deux composantes, horizontale et verticale, de la perméabilité à l\u27air.- étude de l\u27évolution de la perméabilité à l\u27air du sol en fonction du degré de saturation de celui-ci en liquides. - vérification de la validité ou non de l\u27utilisation des colonnes unidirectionnelles dans le dimensionnement des systèmes d\u27extraction en se basant sur l\u27atteinte d\u27une vitesse critique de l\u27air au sein des pores du sol. Pour accomplir ces objectifs, un pilote d\u27essai a été conçu et réalisé, plusieurs expériences ont été effectuées et des modèles de la littérature ont été utilisés. Les résultats obtenus ont montré que la méthode la plus adaptée à la détermination de la perméabilité à l\u27air du sol est celle mettant en uvre un régime stationnaire sans couverture à la surface du sol, Et que les résultats obtenus dans une colonne unidirectionnelle concernant la vitesse critique ne peuvent être extrapolés à l\u27échelle du terrain comme il se fait actuellement

Étude de la dépollution des sols par extraction sous pression réduite (application au traitement des COV)

L extraction sous pression réduite est l une des techniques de dépollution envisageables lorsqu il y a contamination d un sol par des composés organiques volatils (COVs). Cette technique consiste à créer une dépression dans le sol et induire un écoulement contrôlé d air qui entraînera les contaminants volatils dans la phase gazeuse extraite. Les objectifs de ce travail peuvent se résumer de la façon suivante : - caractérisation de la méthode la plus adaptée à déterminer les deux composantes, horizontale et verticale, de la perméabilité à l air.- étude de l évolution de la perméabilité à l air du sol en fonction du degré de saturation de celui-ci en liquides. - vérification de la validité ou non de l utilisation des colonnes unidirectionnelles dans le dimensionnement des systèmes d extraction en se basant sur l atteinte d une vitesse critique de l air au sein des pores du sol. Pour accomplir ces objectifs, un pilote d essai a été conçu et réalisé, plusieurs expériences ont été effectuées et des modèles de la littérature ont été utilisés. Les résultats obtenus ont montré que la méthode la plus adaptée à la détermination de la perméabilité à l air du sol est celle mettant en œuvre un régime stationnaire sans couverture à la surface du sol, Et que les résultats obtenus dans une colonne unidirectionnelle concernant la vitesse critique ne peuvent être extrapolés à l échelle du terrain comme il se fait actuellement.Soil Vapour Extraction (SVE), which includes gas extraction and/or gas injection, is the primary method used to remove volatile organic compounds (VOCs) from unsaturated subsurface porous media. The widespread use of SVE is due to its above ground simplicity of operation and proven ability to remove contaminant mass inexpensively relative to competing technologies. The objectives of this study may be summarized as follow: - Characterisation of the more appropriate method to determine horizontal and vertical soil air permeability components. - Study of the evolution of soil air permeability as a function of liquids saturation degree. - Verification of the validity or not of the use of unidirectional columns in extraction systems design based on attainment of a critical pore-gas velocity. To accomplish these objectives, a laboratory pilot was designed and realised, a series of experimental tests was conducted and literature models have been used. Results showed that the more appropriate method to determine soil air permeability is the one which involve stationary state in an open soil and that results obtained with a unidirectional column related to critical air velocity can not be extrapolated to field scale as it's currently done.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Application of electrocoagulation process for the removal of chloroquine from an aqueous solution

Using chloroquine (CQ) as a provisional treatment for COVID-19 patients generates more pharmaceutical waste, posing a potential environmental threat. The present study evaluates the feasibility of the electrocoagulation (EC) process in removing CQ from an aqueous solution. The experiment was performed in a laboratory-scale stirred tank reactor (STR). The effects of operating conditions were investigated. Equilibrium and kinetic experiments were also performed to describe CQ adsorption. The results showed that increasing both the applied current density and the EC reaction time increases the removal efficiency of CQ. The results showed that 95% of CQ removal efficiency was achieved at a current density of 66.89 mA/cm2, 600 rpm of agitation rate, 60 min of electrolysis time, an initial CQ concentration of 3 mg/L, and a pH of 6.5. For equilibrium and kinetic studies, the Langmuir isotherm and the pseudo-second-order provided the best fit to the experimental data. The optimal operating conditions led to a specific amount of dissolved aluminum electrodes and a specific energy consumption of 0.228 kg/m3 and 12.243 kWh/m3. These results suggest that the EC process is an excellent tool for effectively degrading CQ from wastewater with a low operating cost (2.48 USD/m3). HIGHLIGHTS Several studies have proven that chloroquine is suitable for treating an infection with SARS-CoV-2.; Huge consumption of chloroquine drugs generates large amounts of pharmaceutical wastewater.; Operating conditions of the electrocoagulation process were discussed.; The Langmuir isotherm and the pseudo-second-order provided the best fit for the experimental data.; The energy consumption and operating costs were calculated.

Validity of the Use of the Mass Transfer Parameters Obtained with 1D Column in 3D Systems during Soil Vapor Extraction

International audienceThe efficiency of soil vapor extraction (SVE) depends primarily on mass transfer parameters. The objective of this work was todetermine whether mass transfer parameters obtained from calibrating a model against unidirectional column experiments could be used forthree-dimensional (3D) applications. A 3D experimental setup was designed and constructed to simulate a decontamination system at thebench scale. A mathematical model simulating multiphase flow and multicomponent transport of contaminants in the subsurface undernonequilibrium transient mass transfer conditions was developed and used. Results showed that the mass transfer parameters obtainedfrom unidirectional column assays were several orders of magnitude greater than those obtained with the 3D trials. Quantitative analysesof the experimental data showed that mass transfer limitations occurred in 3D. Mass transfer coefficients are related to the distribution ofair velocity in the 3D reactor. Consequently, unlike the 1D column, mass transfer coefficients may not be linked to a single value of airvelocity

Corrigendum to: Sustainable Solid Waste Management in Morocco: Co-Incineration of RDF as an Alternative Fuel in Cement Kilns

The management of municipal solid waste (MSW) is a major obstacle for the majority of municipalities in developing countries because of the impacts related to the landfilling of waste. Garbage is an energy-rich material. As a result, energy recovery is considered to be a sustainable waste management method. In Morocco, 7.4 million tons are produced annually; most of the waste is landfilled without any recovery despite the impacts related to this method of disposal. The objective of this chapter is to characterize combustible fractions (RDF) from household waste in Morocco and to study the economic and environmental benefits of their use as alternative fuels in cement kilns. The results of this research show that the combustible fractions contained in household waste in Morocco constitute a potential sustainable energy source with a high lower calorific value (4454 kcal/kg). The study of the advantages of co-incineration shows that the substitution of pet coke by 15% RDF reduces the pollution linked to gaseous emissions. In addition, the cement plant can make financial savings 389 USD/h by minimizing the use of fossil fuels

Environmental Impact Assessment of Taza City’s Wastewater: Application through Principal Component Analysis

Taza City is among the Moroccan cities which is in full urban expansion, with a daily wastewater discharge volume estimated at 16534 m3/d in 2020, and expected to reach 20056 m3/d by 2030. These waters, collected in a combined sewerage network, are directly released into the natural environment without any treatment. Indeed, a large part of this water is discharged into Oued Defali, the main tributary of Oued Larbâa. In order to manage and better understand these discharges impact on the streams crossing this city, wastewater sampling campaigns were carried out for one year from May 2018 to April 2019 at domestic (S1) and industrial (S2) sites. The wastewater physicochemical characterization revealed that these discharges are highly loaded with organic matter in terms of chemical oxygen demand (S1 avg = 1231.44 mg/l and S2 avg = 933.03 mg/l), biochemical oxygen demand (S1 avg = 511.87 mg/l and S2 avg = 464.35 mg/l), and suspended matter (S1 avg = 744.11 mg/l and S2 avg = 578.13 mg/l). The use of principal component analysis (PCA) has allowed us to collect as much information as possible from the database of the physicochemical analyses performed for the studied parameters

Evaluation of Activated Carbons Prepared from Bioprecursors for the Removal of Cadmium and Chromium (VI)

Trace metals found in industrial effluents are highly toxic pollutants, and these include cadmium and chromium (VI). The objective of this work is to remove cadmium and chromium (VI) on activated carbons, prepared from biomaterials such as nuclei of Ziziphus lotus and coffee grounds. The characterization of adsorbents was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results of the characterization showed an important porosity on the activated carbon’s surface, with sizes between 6 and 50 μm. Similarly, the adsorption results showed that the adsorption process is very rapid and that the increase in contact time and temperature improves the efficiency of the Cd and Cr(VI) removal process. Indeed, abatement rates (R%) of 80% for Cr(VI) and 60% for Cd were obtained after 80 minutes of adsorption on activated carbon prepared from Ziziphus lotus, whereas activated carbon obtained from coffee grounds allows a reduction rate of about 50% for Cr(VI) and Cd. Hence, it seems clearly that the activated carbon of Ziziphus lotus is more effective than that of coffee grounds, especially for the Cr(VI) adsorption. The kinetic modeling of the adsorption process followed the pseudo-second-order model, and the Freundlich model has better explained the adsorption isotherm for Cd and Cr(VI). The thermodynamic study showed that adsorption was spontaneous and endothermic