Coupling of abiotic and biotic parameters to evaluate performance of combining natural lagooning and use of two sand filters in the treatment of landfill leachates.

A study in the Etueffont landfill, located in Belfort (France), was conducted to evaluate the performance of combining natural lagooning and use of two sand filters for treating leachates through the coupling estimation of several abiotic and biotic parameters. Two gravel filters were installed in the upstream of the first basin which communicates with the remaing 2, 3 and 4 basins. The distribution of physical-chemical (T, pH, Eh, EC, O2, SM, SO4(2-), Cl-, Zn, Fe, Mg, Ni, Al, As, Ba, Cu, Sn, Zn, BOD, COD, KN, NH4+, NO2+ ,TP, AOX: absorbable organic halides, VFA: volatile fatty acids, and atrazine) and biological (bacteria, protozoa, phytoplankton) parameters was assessed in the leachate entering in basin 1, and downstream of the filters. The results showed slight variations in the physical-chemical composition of the leachate between 1999 and 2000, most likely ascribed to the maturation of the landfill but a very significant removal of SM (suspended matter) by the sand filters. This, applied to the majority of the studied parameters. Thus, the sand filter treatment of the leachates combined with natural lagooning was efficient in the improvement of water clarification.

The bacteria in the sediment of the Sahela reservoir (Morocco): potential impacts on phosphorus budget.

Temporal variations of phosphorus concentrations, bacterial abundance and activity of fractionated (i.e: size fractions: 0.22 to 0.65 microm; 0.65 to 100 microm and 0.22 to 100 microm) alkaline phosphatase (APA) were studied in situ in a benthic chamber placed in a station near urban inputs in the Sahela reservoir (Morocco) on September and October 98. Results show that low oxygen concentrations induced enhanced concentrations of orthophosphates, and bacterial numbers and APA activity reached their highest values. Anoxic conditions and the decrease of pH favour the dissolution of particulate phosphorus and the release of soluble reactive phosphorus. This release is accompanied simultaneously by an increase in the abundance of anaerobic bacteria and a progressive reduction in APA. Lastly, the release of phosphorus together with urban inputs from the city of Taounate should be considered as potential inducers of the eutrophication of the reservoir.

Some characteristics of the HIV epidemic in Morocco.

The first case of AIDS in Morocco was declared in 1986 and since then the number of AIDS cases has steadily increased. According to the Ministry of Health, the cumulative number of AIDS cases in December 2002 was 1085. HIV in Morocco is acquired mainly through heterosexual intercourse. Individuals aged between 30 and 39 years and in the regions of Marrakech and Agadir have been the most affected. Monitoring of the trend of the epidemic by sentinel surveillance surveys indicates that Morocco is still a low prevalence zone, since prevalence among pregnant women is less than 1%. The estimated number of HIV-infected people in Morocco is around 15 000. It is not clear why the epidemic here has not evolved as it has in the sub-Saharan countries where it is spreading at an alarming rate. Late introduction of HIV-1 subtype B in Morocco, which is relatively less transmissible, circumcision and reduced risk behaviours of Muslims may explain this. Nonetheless, because prevalence has increased in recent years, unless preventive measures are strengthened, the HIV epidemic will worsen in Morocco.