A. Toumi

Cadi Ayyad University, Maraksh, Marrakech-Tensift-Al Haouz, Morocco

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Publications (5)5.99 Total impact

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    ABSTRACT: Heavy metals (Zn and Cd) effect and their bioaccumulation by a microalga Micractinium pusillum were investigated. Results showed that Cd was more toxic than Zn on Micractinium pusillum. Indeed, inhibitory concentrations of 50% of alga population in 72h (IC50,72h) were 0.28 and 0.34 mg l−1 respectively for Cd and Zn. On the other hand, metal extracted rates from medium solution were more important for Zn than for Cd, essentially for the two first concentrations tested (0.06 and 0.12 mg l−1). Furthermore, Zn and Cd extracted proportions were more important for the low concentrations tested and decreased progressively with increasing concentrations applied. This mechanism of extraction corresponds principally to their biosorption by Micractinium pusillum.
    No preview · Article · Jan 2007 · Environmental Technology
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    ABSTRACT: Heavy metals (Zn and Cd) effect and their bioaccumulation by a microalga Micractinium pusillum were investigated. Results showed that Cd was more toxic than Zn on Micractinium pusillum. Indeed, inhibitory concentrations of 50% of alga population in 72h (IC50,72h) were 0.28 and 0.34 mg l−1 respectively for Cd and Zn. On the other hand, metal extracted rates from medium solution were more important for Zn than for Cd, essentially for the two first concentrations tested (0.06 and 0.12 mg l−1). Furthermore, Zn and Cd extracted proportions were more important for the low concentrations tested and decreased progressively with increasing concentrations applied. This mechanism of extraction corresponds principally to their biosorption by Micractinium pusillum.
    No preview · Article · Dec 2006 · Environmental Technology
  • A Toumi · A Nejmeddine · M Belkoura
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    ABSTRACT: Removal of heavy metals (Zn, Cu, Pb, Cd and Cr) by an integrated wastewater treatment system, Two Phase Anaerobic Reactor (RAP) - High Rate Algal Pond (HRAP), was investigated. Results indicate a good reduction of these micro-pollutants by this system. Global elimination rates of treatment system are 80%, 87%, 38%, 60% and 63%, respectively for Zn, Cu, Pb, Cd and Cr. Primary treatment (RAP) was not involved in this reduction. Metal concentrations detected in RAP effluent are higher than those detected in raw wastewater. However, the essential metal removal was ensured by the HRAP and thetwo maturation ponds. Sedimentation of metals adsorbed on suspended matters is the principal factor that intervened in metal elimination by these ponds. Indeed, metal analysis of wastewater dissolved and particulate fractions showed that the majority of these cations was in particulate fraction, notably for Zn, Cu, Cd and Cr. Their distribution between these fractions evolved towards their solubilization, during the treatment. Otherwise, metal sediment analysis of different ponds showed that sludges accumulate important quantities of metals, especially in RAP sludges. Thereafter, Zn, Cu and Cd concentrations increased in HRAP sludges, but Pb and Cr contents decreased. However, in maturation pond sludges metal quantities are lower. On the other hand, metal contents in sludges are variable from upstream to downstream of each pond.
    No preview · Article · Mar 2003 · Environmental Technology
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    ABSTRACT: The present study is concerned with a incubation process of following the evolution of NH4+ in two different soils (clay and sand) which receive two type of waste of tannery, that is tanned waste (which are full of chromium) and untanned ones. The obtained results indicate that the elimination proportion of the NH4+ is higher within an amendment by untanned waste than by tanned ones. While the concentration of tanned of waste increases, the oxidation of NH4+ decreases. This is probably linked to the chromium concentration in brought by the tanned waste. The obtained results reveal also that the oxidation of NH4+ is the function of the soil nature. This was also confirmed by determining the inhibition constancy (Ki) of Cr. The inhibition of the nitrification caused by different chromium concentrations is higher in the clay soil (0.99 g Cr/kg MS) than in tpe sand soil (2.38 g Cr/kg MS). Nitrification is also influenced by temperature.
    No preview · Article · May 2000 · Agrochimica -Pisa-
  • A. Toumi · A. Nejmeddine · B. El Hamouri
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    ABSTRACT: Heavy metals, zinc (Zn), copper (Cu) and lead (Pb) removal in two wastewater treatment units were compared. One of the systems consisted of a train of Waste Stabilisation Ponds (WSP) including one anaerobic three facultative in series and two maturation ponds, also in series. The other system, called High Rate Ponds (HRP) consisted of one anaerobic, one High Rate Algal Pond (HRAP) and two maturation ponds in series. The two treatment systems were located on the same site and received the same wastewater. Data collected from the two treatment systems, for a period of three consecutive months (May, June and July, 1995) show that the content of the three elements in the crude wastewater of the city of Ouarzazate varied from 210 to 340 mg/l for Zn; 35 to 55 for Cu and 30 to 25 for Pb. The removal rate for the three elements reached 91, 92 and 71% respectively for Zn, Cu and Pb in the WSP train. The corresponding values in the HRP train were respectively 89, 88 and 51%. However, since the two trains were not receiving the same flow, the use of specific removal rate expressed as mg removed m-2 d.1 showed that the HRAP was 1.3, 10 and 2 times more efficient respectively for Zn, Cu and Pb removal than the three facultative ponds in series of the WSP. Also, the collected data showed that the content of the sediment of the anaerobic pond was high for all the three elements. However, the recorded concentrations 613, 99 and 78 mg/kg, respectively for Zn, Cu and Pb did not exceed the EEC recommended limits.
    No preview · Article · Jan 2000 · Water Science & Technology