Physico-chemical Characterization of Industrial Effluents from the Town of Ouargla (South East Algeria)

International audienceIn order to preserve the quality of our environment and public health, regulatory treatment of pollutants is constantly changing to more restrictive standards. Thus, the problem of organic pollutants has emerged as a major issue in the treatment of industrial wastewater (ERI). The objective of this work was the evaluation of the above organic pollution load of wastewater from some industrial sites in the city of Ouargla (Algeria). The water samples were collected from seven different sites, hospital, washing stations, a slaughterhouse and a processing plastic plant. The physico-chemical characterization of raw sewage revealed that these releases are loaded with organic matter in terms of COD (153.6 to 36120 mg/L) BOD5 (100 to 4700 mg/L) TSS (29 to 14702 mg/L). For the majority of the studied parameters, Algerian industrial waste often exceeded the required standards, since wastewater has a high organic load (BOD5/COD = 0.012 to 0.45 and TSS/BOD5 = 0.2625 to 73.51, COD/BOD5 = 2.23 to about 80000), showing in most cases poor biodegradability

Joint use of color space and wavelet transform for SPOT and RADARSAT image fusion

peer reviewedNous proposons dans cet article une méthode de fusion des images multispectrales et radar par l'utilisation conjointe de l'espace des couleurs et de la transformation en ondelettes. La transformation de l'espace des couleurs permet une séparation des informations spatiale (composante lumineuse) et spectrale (composantes teinte et saturation). La substitution de la composante luminance par une combinaison luminance-radar permet de produire des images fusionnées multispectrale-radar. Celle-ci est produite au moyen d'un processus de fusion appliqué dans le plan des ondelettes pour exploiter les informations contenues dans les images luminance et radar. Pour cela, nous développons un modèle de fusion dépendant des coefficients d'ondelettes et d'un paramètre de fusion qui permet de régler le poids relatif des informations luminance et radar dans le processus de fusion. Un tel paramètre dépend de l'énergie des coefficients qui constitue un bon indicateur de l'importance des coefficients luminance et radar. Pour montrer l'intérêt et l'impact de cette méthode, nous l'évaluons, de façon qualitative et quantitative, sur des images HRV de SPOT et RSO de RADARSAT couvrant une région du Viêt-nam (Haïphong). L'évaluation qualitative révèle que l'information radar est injectée dans les images multispectrales lorsque celle-ci est suffisamment dominante. Cela est mis en évidence par l'examen du paramètre de fusion. Par contre, l'évaluation quantitative, par l'utilisation du coefficient de corrélation et l'écart spectral, montre que les propriétés spectrales sont mieux préservées comparativement à la méthode conventionnelle de substitution de la composante luminance par l'image radar.Usually, two methods are used for using optical and radar images. The first method uses the colour space as the intensity-hue-saturation (IHS) representation for using the multispectral and radar (R) images. It consists in substituting the spatial component (I) by the radar image. Multispectral-radar images are then produced by applying the inverse IHS transform. The second method exploits the wavelet transform (WT) for using panchromatic and radar images by means of a criteria defined in the wavelet domain. The orginality of this work lies in the joint use of the IHS and the wavelet transform for using multispectral and radar images. The development of this method is motivated by the fact that the direct substitution of the I component by the radar image corresponds to rejecting all information coming from the I component. While, this component contains also important information's that should be preserved in the composite image. For this, we propose a more appropriate procedure wich consists in producing a composite I-R component through a combination of the I and R images in order to substitute it to the I component. To ensure that all significant features are selected into I-R, we develop a model, in the wavelet domain, wich allows an adaptative selection of dominant features. This model is a function of I and R wavelet coefficients and a fusion parameter wich allows indicates the relative importance of two components. Such a parameter ranges from zero to one and depends of wavelet coefficient energy. When this parameter tends to zero, the k wavelet coefficient is retained in the I-R comportment. Otherwise, when the parameter tends to one, the I wavelet coefficient is retained. For values of the parameter between these two extreme values, both I and R wavelet coefficients contribute in the I-R comportment. In order to evaluate the interest and the impact of this method, we test it on HRV (XS1, XS2, XS3) images of SPOT and RSO image of RADARSAT covering a region of Viêt-nam (Haïphong Bay). The qualitative evaluation indicates that the radar information is introduced into multispectral images when the details are sufficiently dominant. This is pointed out by examining the values of the fusion parameter through scales wich are represented as images. These constitute a good indicator to point out the relative importance of the I and R information for each region of the images. They may thus be helpful for better interpretation. In order to evaluate, in terms of spectral content, the resemblance of multispectral and fused multispectral-radar images, we use two measures based on correlation coefficient and index deviation. These two measures reveal a better preservation of the spectral properties by our method

Synthesis and characterization of pine cones biochar for the removal of an antibiotic (Metronidazole) from aqueous solutions

International audienceThis study aimed to develop a potential biochar derived from pine cones for the removal of metronidazole from water. Biochars were prepared at three different pyrolysis temperatures (500, 700, and 900 and DEG;C) in order to select the best biochar with the highest metronidazole removal efficiency. The findings showed that the specific surface area increased with increasing pyrolysis temperature: 64.77 m2/g for 500 and DEG;C, 353.97 m2/g for 700 and DEG;C, and 597.97 m2/g for 900 and DEG;C, as well as the micropore volume, which increased by 89.18% when the temperature increased from 500 to 900 and DEG;C. This improvement favors the pore-filling mechanism. The structural aromatic carbon is formed when the hydrogen, oxygen, and volatile car -bon are removed. Thus, the p-p interaction mechanism is included in metronidazole adsorption since it is an organic pollutant with an aromatic structure. The adsorption kinetics results highlighted that metron-idazole was effectively removed (98.57%) when using PCB-900 and DEG;C. The kinetic adsorption was described by the pseudo-second-order model. The adsorption capacity of the Langmuir isotherm was 138.94 mg/g. It also appeared that the pH medium did not have a considerable effect on metronidazole adsorption, indicating that electrostatic interactions did not have a significant effect on the process. According to the thermodynamic study, the adsorption of metronidazole was spontaneous and endothermic. The reuse of PCB-900 and DEG;C was tested in 8 cycles with an efficiency decreasing from 98.57% to 37.89%. Thus, it can be concluded that the PCB-900 and DEG;C constitutes a promising adsorbent for metronidazole removal from aque-ous solutions.and COPY; 2023 The Korean Society of Industrial and Engineering Chemistry

Biological Filtration on Sand of Dunes – Filters Fouling

International audienceThe use of sand of dunes as a filtration support for domestic wastewater treatment demonstrated its efficiency at pilot scale. However, the filter receives non negligible amounts of suspended matter, leading to biological clogging owing to the colonization of the pores of the filtration media by biomass and related by-products. Fouling time-course was examined in this work. Measurements carried out at various column heights showed that the difference of porosity between the first and last layers can reach 2%, while the decrease between the initial and the final state was above 7% for all layers. Organic matter accumulation followed similar history than fouling, showing its involvement in the process and its preponderance in the fouling mechanism if compared to mechanical fouling. The amount of organic matter was mainly apparent in the two upper layers of sand and exceeded 2% in the first sand layer after 7 day

Influence of Secondary Salinity Wastewater on the Efficiency of Biological Treatment of Sand Filter

International audienceAs preventive of possible environmental nuisances that can cause discharges water in nature, we undertook this study of the influence of salinity wastewater on the treatment efficiency of a biological filter consisting of dune sand. In this work, we designed six identical columns of filtration with sand from the same region of the N’Goussa city (located in the southeast of Algeria). The filters used are fed with wastewater at six different total salinity rates ranging from 0.065% to 0.265% corresponding to the electrical conductivity of 0.85 mS/cm to 3.5 mS/cm. This filtration efficiency was assessed by monitoring changes in the conductivity and the overall pH of the treated water and the chemical oxygen demand (COD). The results obtained showed that the change in the salinity of sewage water has a negative effect on the degradation of organic matter. Indeed, over the salt content is high, over the effectiveness of the biological treatment is reduced, suggesting in this type of case a prior desalination system and tests are under way in our laborator

Sustainable pine cone adsorbent: Removal of prednisolone and pre-treatment of a medical lab wastewater

International audienceThe current study aimed to investigate at lab-scale the removal of a steroid anti-inflammatory “prednisolone” from synthetic solutions and the pretreatment of a medical analysis laboratory's wastewater using an efficiently prepared adsorbent. To achieve this goal, two adsorbents were prepared from pine cones. The first one is a pine cones biochar prepared by pyrolysis at 900 °C (PCB-900 °C), while the second adsorbent was phosphoric acid-activated carbon subjected to pyrolysis at 400 °C (PhAC). The obtained results demonstrated that PCB-900 °C outperformed PhAC, achieving an efficiency of 99.10% in prednisolone removal, whereas PhAC attained an efficiency of 31.63% within 30 min equilibrium time. The pseudo-second-order kinetic model describes perfectly the kinetic adsorption data of prednisolone for both adsorbent. The maximum adsorption capacity of Langmuir obtained by the best-prepared adsorbent (PCB-900 °C) was 35.99 mg/L. The adsorption process remained unaffected by variations of pH; electrostatic interactions have not a major effect on the adsorption process. The π-π interactions, pore-filling and hydrophobic interactions were selected as the dominant mechanisms involved in the adsorption process of prednisolone. The thermodynamic study highlighted that the adsorption process of prednisolone on PCB-900 °C was spontaneous, endothermic, and random. The reutilization of PCB-900 °C was tested on 4 consecutive cycles. The results of the degradation of organic matter in laboratory wastewater showed that high dose of PCB-900 °C led to significant reductions in chemical oxygen demand (COD) and turbidity levels. Therefore, pine cone-derived biochar can be considered as a solution for pharmaceutical removal and an eco-friendly method for treating point sources of pharmaceutical effluent

A comparative study of the addition effect of activated carbon obtained from date stones on the biological filtration efficiency using sand dune bed.

International audienceUp to now, even with the tremendous social and technological progress, pollution problems still occupy the focus of many researchers all over the world, and hence this paper focused on the treatment of domestic wastewater. In this context, a bi-layer filtration system made of sand dune and activated carbons have been developed. This latter was obtained from the hydrolysis of local date stones. The total thickness of the filter media was 60 cm. The height of the resulting bed ranged from 0 to 24 cm, and was controlled by adding only activated carbons. The efficiency of the filtration system was evaluated by monitoring the time-courses of COD and BOD5 values, as well as their evolution over the height of the bed. The comparison of these results to those obtained with a bed of sand dune only showed a clear enhancement of the efficiency which lay between 80-95 (%) for COD and 78-94 (%) for BOD

Comparative Study between Two Granular Materials and their Influence on the Effectiveness of Biological Filtration

International audienceIn the interests of preserving our environment from all forms of pollution, we have undertaken a series of studies of purification of sewage based on the phenomenon of biological filtration. In this work, we have made a comparative study between two types of granular materials by filtration, the (artificial) crushed glass and sand dunes (natural). These two materials are using as filter media on columns to a height of 60 cm. The effectiveness of this model is essentially assessed through indicators parameters of organic pollution chemical oxygen demand (COD) and the biochemical oxygen demand (BOD5). The results obtained showed a removal of oxidizable organic matter at 93.24%, and biodegradable surroundings 98.93%. These results are very interesting and satisfactory at several levels including in terms of safeguarding our ecosystem of some pollutant nuisances and especially by the exploitation of natural resources or recycling of glass released into natur

A comparative study of the efficiency of the biological filtration on a Aeolian sand and an alluvial sand

International audienc

Green Fabrication of ZnO Nanoparticles and ZnO/rGO Nanocomposites from Algerian Date Syrup Extract: Synthesis, Characterization, and Augmented Photocatalytic Efficiency in Methylene Blue Degradation

International audienceThis innovative article provides a detailed description of the successful biosynthesis of zinc nanoparticles (ZnO-NPs) using an aqueous extract of Algerian Date Syrup, also known as molasses. A meticulous process was carried out to determine the optimal calcination temperature for ZnO-NPs, a crucial step in the preparation of these nanoparticles. The study was further extended by creating ZnO/rGOx nanocomposites through a hydrothermal method, varying the concentrations of reduced graphene oxide (rGO) at 5%, 10%, and 15%. The characteristics of the nanocomposites were thoroughly explored, encompassing chemical, optical, and morphological aspects, using sophisticated analysis techniques such as scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (UV DRS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). These analyses provided an in-depth understanding of the structure and properties of the nanocomposites. The centerpiece of this study is the evaluation of the photocatalytic degradation capacity of ZnO-NPs and ZnO/rGOx nanocomposites. These materials have demonstrated their ability to act as cost-effective and environmentally friendly photocatalysts for wastewater treatment. Experiments on methylene blue degradation under UV irradiation were conducted, yielding impressive results: a degradation efficiency of 86.6% was achieved in 140 min using 1 g/L of ZnO-NPs, and this rate reached 100% with the ZnO/rGO catalyst in the same time frame, highlighting its superiority as a photocatalyst. Furthermore, this study examined the variables affecting the photocatalysis experiment, including the solution’s pH and the amount of catalyst. The results revealed that the ZnO/rGO photocatalyst reached its optimal efficiency under neutral pH conditions and at a concentration of 1 g/L, providing crucial information for practical use of these materials. This enriched article highlights the promising potential of ZnO-NPs and ZnO/rGOx nanocomposites as efficient photocatalysts for methylene blue degradation, paving the way for significant environmental applications in wastewater treatment