Removal of dissolved and particulate form of metals (Cu, Zn, Pb, Cd) by ananaerobic pond system in Marrakesh (Morocco).

The purpose of the present work was to investigate the elimination of heavy metals contained in the wastewaters of Marrakesh city (Morocco) by an anae robic lagoon system under dry climate. These wastewaters were loaded with h eavy metals (Cu, Zn, Pb and Cd). Compared to the norms of water reuse for i rrigation, the total concentration of Cd exceeded the maximal level recomme nded by the Food Agriculture Organization (FAO). The anaerobic stabilizatio n pond reduced the load of Zn, Cu and Pb with respective efficiencies of 28 %, 21% and 11%. Heavy metal elimination through this type of pond system wa s essentially by settling of particulate forms. The decanted sludge is domi nated by tiny fractions loaded with heavy metals with increasing amounts fr om the inlet to the outlet of the lagoon.