Epuration des effluents industriels par électroflottation

L’utilisation de l’électricité comme mode direct de traitement des effluents est un domaine en pleine expansion. En effet, la diminution du prix de l’électricité couplée aux facilités d’automatisation de tels procédés rendent ces techniques plus attractives, particulièrement lors de la mise en place de petites unités de traitement. Dans ce travail, un modèle réduit d'électroflottation conçu et réalisé au laboratoire, traite des solutions artificielles (eau et gel de silice Ø50 < 25 mm) à différentes tensions (10, 15, 20 et 25 V volts) tout en modulant la distance entre les électrodes (1, 2 et 3 cm), pour optimiser les paramètres de traitement (temps de traitement, écart entre les électrodes, tension d'alimentation). L'application des paramètres optimisés sur les eaux de rejets du complexe industriel ALCOVEL d'Akbou a montré, une réduction de la demande biologique en oxygène (DBO5), la demande chimique en oxygène DCO, la turbidité, les MES et de la couleur de 93.5 %, 90.3 %, 78.7 %, 93.3 % et plus de 93%, respectivement. Dans la deuxième partie, nous avons étudié la séparation de quelques métaux lourds tels que le fer, le nickel, le cuivre le zinc, le plomb et le cadmium. Cela nous a permet de montrer que le taux d'épuration atteint les 99 % et la cinétique d'électroflottation ne dépasse pas les 15 minutes.Mots clés: électroflottation; électrodes en aluminium; turbidité; effluents industriels; métaux lourds, spectrométrie. The present work purpose is to study experimentally the clarification of wastewater using the electroflotation technique. In a first part, we have realized the bench scale. After that, we have studied the principal parameters (alimentation tension, distance between electrodes, period of treatment) affecting the process using a simulated model of wastewater. The application of the optimized parameters on wastewater of the treatment station of ALCOVEL, showed a high removal of BOD5, COD, turbidity, SS and colour. In a second part, we have studied the separation of some heavy metals such as iron, nickel, copper, zinc, lead and cadmium. This, permeated us to show that the kinetic of electroflotation is very quick (<15 min), and the removal rate reach 99%.Keywords: electroflotation; aluminum electrodes; turbidity; industrial wastewater; heavy metals; spectrometry

Bilan hydrologique et envasement du barrage Saboun (Maroc)

La présente étude s'inscrit dans le cadre d'un programme de recherche sur la gestion des lacs et barrages collinaires en zone méditerranéenne HYDROMED. Elle a pour objectif le suivi hydrologique et la sédimentation du barrage collinaire Saboun, situé dans la zone de Tanger au Nord-Ouest du Maroc. Un dispositif hydro-pluviométrique automatique a été installé à ce sujet depuis novembre1997. Il a permis le suivi du bilan en eau de la retenue et l'analyse de son fonctionnement hydrologique. Parallèlement, une étude de la bathymétrie par sondage ponctuel a montré que le taux de sédimentation est de l'ordre de 2% par an. Cette perte en eau de la capacité totale de la retenue est une conséquence directe d'une forte dégradation des sols du bassin versant estimée à 115 T/ha/an.It is proposed that many Mediterranean countries could make better use of their water resources by constructing small hill reservoirs. Since 1980, Morocco has built more than 158 small dams in order to meet the requirements of rural population water use. Due to both environmental degradation and bad management, these small infrastructures are now in a critical situation. Furthermore, pollution and siltation, resulting in a deterioration of water quality and a reduction of water capacity, are problems at these sites.The present study is part of the HYDROMED research program on the hydrological balance of small dams in the Mediterranean area. Its objective is the monitoring of hydrological balance and siltation of a small dam, Saboun, located in Tangier in Northwest Morocco. A remote hydrological station was installed in November 1997. This station allowed the examination of the dam water balance and analyses of its hydrological function.The analyses of water balance demonstrated that the volume of water stored in the Saboun reservoir increased rapidly in November 1997, and was then followed by a progressive decrease. The load factor varied from 1.9 in 1997/98 to approximately 2 times the current capacity of reservoir, to only 0.3 in the following year 1998/99. These results show that even for a short hydrological period (2 years), the hydrological balance of the Saboun reservoir varied greatly as a result of the irregularity of its hydrological parameters. The essential reasons for this variability were the rainfall characteristics that control the runoff from the watershed and bad management practices.In addition, a bathymetric survey was carried out by a punctual method to estimate the rate of dam siltation and sedimentation from the watershed. The results of this control demonstrated that the dam siltation rate was about 2 % per year. This loss of total water retention capacity of the dam is the consequence of high specific soil degradation of the watershed. The rate of sediment delivered from watershed and deposited in the reservoir was estimated at 37 T/ha/year. The total soil erosion for watershed was estimated at 115 T/ha/year by integrating both the sediment evacuated at the time of dam overflow and the sediment deposited in stream flow. This erosion, which comes essentially from cultivated soil (95 % of the watershed surface), may have serious effects on the hydrological balance of the dam, particularly by reducing the reservoir capacity of the dam, and on the reservoir water quality

GENERATING FUNCTIONS OF THE PRODUCT OF 2-ORTHOGONAL CHEBYSHEV POLYNOMIALS WITH SOME NUMBERS AND THE OTHER CHEBYSHEV POLYNOMIALS

In this paper, we give the generating functions of binary product between 2-orthogonal Chebyshev polynomials and kFibonacci, k-Pell, k-Jacobsthal numbers and the other orthogonal Chebyshev polynomials

CONTROL OF A THREE LEVELS AC/DC CONVERTER WITH VIRTUAL-FLUX DIRECT POWER CONTROLLING METHOD FOR GRID-CONNECTED WIND POWER SYSTEM UNDER GRID’S FAULT

The present work focuses on modelling of sensor-less Direct Power Control based on Virtual Flux (DPC-VF) for three levels AC/DC converter for wind power system in the case of grid abnormality. As a fact, when an unbalance appears in the grid, the negative sequence affects the quality of Dc-link at the output of the converter and makes deterioration in grid current. In order to improve the behaviour of the converter under grid abnormality, the grid currents and Virtual Flux are decomposed in separating positive and negative sequence using double second order generalized integrator Direct Power Control (DSOGIFLL) then compensating active and reactive powers are calculated according to the control objective and injected in the referencing one. The proposed controller ensures voltage balance in DC-link capacitors by using redundant vectors in a space vector modulation block without needing additional components. In order to test the effectiveness of the control scheme, a numerical simulation is performed using the Matlab-Simulink software. The results prove the validity of the proposed control algorithm

Assessment of acute and sub-acute toxicity of olive pomace in female Wistar rats

Objective: Olive Pomace (OP) is considered to be a rich source of phenolic compounds. Recently many researches showed a broad biological activity of this by-product of the olive oil production process in addition to their emergence as value-added materials with potential applications in the pharmaceutical, food, and nutraceutical industries. The present study is aimed to evaluate in vivo toxicological activities of OP. Materials and Methods: The qualitative phytochemical analysis aims to determine the key phytoconstituents found in OP. For the in vivo study, two types of tests are performed: acute and 28-day repeated oral toxicity studies in Wistar rats for evaluation of hematological, biochemical, and histological parameters. Results: The qualitative phytochemical analysis has revealed the presence of polyphenols, flavonoids, tannins, saponins, quinones, anthraquinones, terpenoids, and compounds reduced in our methanol extract of OP. In acute oral toxicity, no treatment-related death or toxic signs are observed in female rats for 14 days in 200, 2000, 3000, and 5000 mg/kg doses, besides LD50 value is found to be up to 2000 mg/kg bodyweight. As for the Globally Harmonized System of Classification and Labelling of Chemicals. 28-days sub-acute toxicity study is carried in female rats at four dose levels (3.12, 31.25, 125 and 500 mg/kg), no changes in observation related death and toxic signs when compared with control. The hematological and biochemical investigation shows a significant change (p>0.05) in the high-level doses (500 mg/kg). Conclusions: According to the findings of this study, OP extract has the potential to be used to generate new anti-cancer and antioxidant additives for pharmaceutical and food manufacturing. Long-term in vivo toxicological tests should also be conducted to determine a safe dosage of OP extract

Effects of exposure to cigarette smoke prior to pregnancy in diabetic rats

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to evaluate the effects of cigarette smoke exposure before pregnancy on diabetic rats and their offspring development.</p> <p>Methods</p> <p>Diabetes was induced by streptozotocin and cigarette smoke exposure was conducted by mainstream smoke generated by a mechanical smoking device and delivered into a chamber. Diabetic female Wistar rats were randomly distributed in four experimental groups (n minimum = 13/group): nondiabetic (ND) and diabetic rats exposed to filtered air (D), diabetic rats exposed to cigarette smoke prior to and into the pregnancy period (DS) and diabetic rats exposed to cigarette smoke prior to pregnancy period (DSPP). At day 21 of pregnancy, rats were killed for maternal biochemical determination and reproductive outcomes.</p> <p>Results</p> <p>The association of diabetes and cigarette smoke in DSPP group caused altered glycemia at term, reduced number of implantation and live fetuses, decreased litter and maternal weight, increased pre and postimplantation loss rates, reduced triglyceride and VLDL-c concentrations, increased levels of thiol groups and MDA. Besides, these dams presented increased SOD and GSH-Px activities. However, the increased antioxidant status was not sufficient to prevent the lipid peroxidation observed in these animals.</p> <p>Conclusion</p> <p>Despite the benefits stemming from smoking interruption during the pregnancy of diabetic rats, such improvement was insufficient to avoid metabolic alterations and provide an adequate intrauterine environment for embryofetal development. Therefore, these results suggest that it is necessary to cease smoking extensive time before planning pregnancy, since stopping smoking only when pregnancy is detected may not contribute effectively to fully adequate embryofetal development.</p

Growth factor concentrations and their placental mRNA expression are modulated in gestational diabetes mellitus: possible interactions with macrosomia

<p>Abstract</p> <p>Background</p> <p>Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during pregnancy. GDM is a well known risk factor for foetal overgrowth, termed macrosomia which is influenced by maternal hypergycemia and endocrine status through placental circulation. The study was undertaken to investigate the implication of growth factors and their receptors in GDM and macrosomia, and to discuss the role of the materno-foeto-placental axis in the <it>in-utero </it>regulation of foetal growth.</p> <p>Methods</p> <p>30 women with GDM and their 30 macrosomic babies (4.75 ± 0.15 kg), and 30 healthy age-matched pregnant women and their 30 newborns (3.50 ± 0.10 kg) were recruited in the present study. Serum concentrations of GH and growth factors, <it>i.e</it>., IGF-I, IGF-BP3, FGF-2, EGF and PDGF-B were determined by ELISA. The expression of mRNA encoding for GH, IGF-I, IGF-BP3, FGF-2, PDGF-B and EGF, and their receptors, <it>i.e</it>., GHR, IGF-IR, FGF-2R, EGFR and PDGFR-β were quantified by using RT-qPCR.</p> <p>Results</p> <p>The serum concentrations of IGF-I, IGF-BP3, EGF, FGF-2 and PDGF-B were higher in GDM women and their macrosomic babies as compared to their respective controls. The placental mRNA expression of the growth factors was either upregulated (FGF-2 or PDGF-B) or remained unaltered (IGF-I and EGF) in the placenta of GDM women. The mRNA expression of three growth factor receptors, <it>i.e</it>., IGF-IR, EGFR and PDGFR-β, was upregulated in the placenta of GDM women. Interestingly, serum concentrations of GH were downregulated in the GDM women and their macrosomic offspring. Besides, the expression of mRNAs encoding for GHR was higher, but that encoding for GH was lower, in the placenta of GDM women than control women.</p> <p>Conclusions</p> <p>Our results demonstrate that growth factors might be implicated in GDM and, in part, in the pathology of macrosomia via materno-foeto-placental axis.</p