Utilisation des lichens comme bio-indicateurs de la pollution atmosphérique par le plomb, cadmium et zinc de la région de Rabat-Sale-Zemmour-Zaêr (Maroc)

Au Nord-Ouest du Maroc, la région de Rabat-Salé-Zemmour-Zaêr présente une importance socioéconomique pour le royaume. En effet, elle est sujette à deux sources de pollution; le trafic routier et les rejets des poteries. Considérant le risque de contamination métallique de l’Homme et de l’environnement, une étude a été conduite pour évaluer la pollution métallique de l’atmosphère. Elle a porté sur les bioindicateurs lichens (Xanthoria Parietina). C’est ainsi que des échantillons de thalle de Xanthoria Parietina ont été prélevés au cours de la période située entre janvier et juillet 2007 et trois éléments métalliques Plomb(Pb), Cadmium(Cd) et Zinc(Zn) ont été détectés. Les résultats de suivi spatial obtenus au niveau des quatre stations étudiées (Kamra, Centre ville, Oulja et Allal Behraoui) ont révélé des concentrations moyennes mensuelles dépassant les normes requises à l’exception de la station de Allal Behraoui. Les résultats de suivi temporel obtenus au niveau des lichens montrent que la variation saisonnière atmosphérique des métaux est très marquée avec des teneurs plus élevées en hiver et plus basses en été.Mots-clés : métaux lourds, lichens, plomb, cadmium, zinc, Rabat, salé, Zemmour, Zaêr, Maroc

Étude de la performance de la STEP du centre emplisseur de la société Salam Gaz – Skhirat, Maroc

Le présent travail a pour but de vérifier l’efficacité du fonctionnement de la STEP de la société Salam Gaz. Les eaux traitées sont réutilisées durant le procédé de production de la société. Les résultats de la caractérisation physicochimique des eaux usées brutes ont montré que les paramètres analysés dépassent les valeurs limites de rejets directes ou indirectes. Les valeurs moyennes en MES, DBO5 et DCO de l’eau brute sont respectivement 3429, 447 et 698 mg/L. Les rendements d’éliminations des paramètres MES, DCO et DBO5 par la STEP sont respectivement 99%, 86%, et 84% alors que l’abattement de la teneur en chrome, cuivre, cadmium et plomb dépasse 90%. Ceci montre que la STEP fonctionne correctement. Toutefois, des améliorations sont nécessaires pour améliorer d’avantages la performance de la STEP. En outre, les eaux usées épurées ont montré un pH acide variant autour de 5 ce qui nécessite une optimisation de la dose du coagulant injecté et une neutralisation avant rejet des eaux traitées dans le milieu récepteur.Mots-clés : eaux usées, diagnostic, performances, recyclage, Salam Gaz – Skhirat, Maroc.Study of the performance of the WWTP filling station company Salam Gas - Skhirat MoroccoThe present work designed to verify the operating effectiveness of society Step Salam Gas. The treated water is reused in the production process of the company. The characterization results at selected tapping points show that the majority of the analyzed parameters exceed the limit values for discharges. The mean values of TSS, BOD5 and COD of raw water are respectively 3429, 447 and 698 mg/l. Yields eliminations parameters TSS, COD and BOD5 by STEP are respectively 99%, 86% and 84% while the reduction of chromium, copper, cadmium and lead in excess of 90%. This shows that STEP is working properly. However, improvements are needed to improve the performance benefits of STEP. In addition, the treated wastewater showed an acidic pH ranging around 5 which requires an optimization of the dose of coagulant injection and neutralization prior to discharge treated wastewater into the receiving environment.Keywords : Wastewater, diagnostic, performance, recycling performance, Salam Gaz – Skhirat, Morocco

Low angle normal faults in Internal rif (Morocco) and their bearing Implication on crustal thinning of the Alboran Domain

Several low angle, shallow dippinng normal faults are described from the internal domaine of the Rif chain. They dip gently towards the Alboran sea and cause important omissions in the stratigraphictectonic pile. These extensionai faults cut through the Ghomaride and Sebtides units and allow explaining the occurrence of flysch klippes overlying the Ghom arides nappes. The age of this extensionai event corresponds to that of the SerravaHan rifting stage of the Alboran seaPlusieurs failles normales à faible pendage inclinées vers la mer d'Alboran sont mises en évidence dans le Rif interne. L'extension associée à ces failles a produit des omissions importantes de terrains et a impliqué dans le déplacement des terrains appartenant au Domaine interne rifain ainsi que des terrains plus externes. Les lambeaux de nappes des flyschs superposés au Domaine interne rifain sont interprétés comme le résultat de ces déplacements extensifs. L'âge de cette extension coïncide avec le stade de rifting du Miocène moyen observé dans ia mer d'Albora

Advanced statistical optimization of parameters of synthesis process of oxygenated carbonated apatite

International audienceThe synthesis process of oxygenated carbonated apatite was optimized by an advanced statistical planning of experiments. Full factorial design of 24 experiments was used to find the effects of five principal parameters: pH of the reaction medium, atomic ratio Ca/P of the reagents, concentration of the calcium solution (Ca2+), temperature of the reaction medium (T) and duration of the reaction (D), with fixing the H2O2 composition at 30% and stirring to 600 turns/min. Studied responses were the atomic ratio Ca/P, % O2, % O2 2− and % CO3 2−. Optimum synthesis parameters were found to be pH = 7.38, Ca/P = 1.647, [Ca2+] = 0.636 M, T = 40°C and D = 1 h. The prediction responses were Ca/P = 1.575, % O2 = 0.76, % O2 2− = 0.50 and % CO3 2−= 1.84. The actual experimental results were in agreement with the prediction

Trends in indices of daily temperature and precipitations extremes in Morocco

The purpose of this paper is to provide a summary of Morocco's climate extreme trends during the last four decades. Indices were computed based on a daily temperature and precipitation using a consistent approach recommended by the ETCCDI. Trends in these indices were calculated at 20 stations from 1970 to 2012. Twelve indices were considered to detect trends in temperature. A large number of stations have significant trends and confirm an increase in temperature, showing increased warming during spring and summer seasons. The results also show a decrease in the number of cold days and nights and an increase in the number of warm days and nights. Increasing trends have also been found in the absolute warmest and coldest temperatures of the year. A clear increase is detected for warm nights and diurnal temperature range. Eight indices for precipitation were also analyzed, but the trends for these precipitation indices are much less significant than for temperature indices and show more mixed spatial patterns of change. Heavy precipitation events do not exhibit significant trends except at a few locations, in the north and central parts of Morocco, with a general tendency towards drier conditions. The correlation between these climate indices and the large-scale atmospheric circulations indices such as the NAO, MO, and WEMO were also analyzed. Results show a stronger relationship with these climatic indices for the precipitation indices compared to the temperature indices. The correlations are more significant in the Atlantic regions, but they remain moderate at the whole country scale

Recent advances in the biological treatment of wastewater rich in emerging pollutants produced by pharmaceutical industrial discharges

Pharmaceuticals and personal care products present potential risks to human health and the environment. In particular, wastewater treatment plants often detect emerging pollutants that disrupt biological treatment. The activated sludge process is a traditional biological method with a lower capital cost and limited operating requirements than more advanced treatment methods. In addition, the membrane bioreactor combines a membrane module and a bioreactor, widely used as an advanced method for treating pharmaceutical wastewater with good pollution performance. Indeed, the fouling of the membrane remains a major problem in this process. In addition, anaerobic membrane bioreactors can treat complex pharmaceutical waste while recovering energy and producing nutrient-rich wastewater for irrigation. Wastewater characterizations have shown that wastewater’s high organic matter content facilitates the selection of low-cost, low-nutrient, low-surface-area, and effective anaerobic methods for drug degradation and reduces pollution. However, to improve the biological treatment, researchers have turned to hybrid processes in which all physical, chemical, and biological treatment methods are integrated to remove various emerging contaminants effectively. Hybrid systems can generate bioenergy, which helps reduce the operating costs of the pharmaceutical waste treatment system. To find the most effective treatment technique for our research, this work lists the different biological treatment techniques cited in the literature, such as activated sludge, membrane bioreactor, anaerobic treatment, and hybrid treatment, combining physicochemical and biological techniques