## 3 Results and Discussion
### Evaluation of Fine Waste-Iron Mobility: Batch Experiments
#### 3.2.2 Mobilisation of Cd and U  
The concentrations of Cd and U, as measured in the leachate from batch tests, are displayed in Figure 5. First, we shall underscore the similarity in the behavior of the two elements throughout the seven cycles for both waste samples; both show a general tendency to increase during the first four cycles to a maximum (17.53 \(\upmu\)g/L and 4.41 \(\upmu\)g/L, respectively, for M'Dhilla, and 8.68 \(\upmu\)g/L and 3.78 \(\upmu\)g/L, respectively, for Redeyef), and with a stabilization (plateau) over the last three cycles, indicating the stability of the fluxes of both elements that go into solution during each cycle at this stage of the experiment. These results show that cadmium is more mobile than uranium because its mobility is more pronounced for the sample FW-ZL. However, the cadmium contents in the leachate, recovered during both batch experiments (11.9 \(\upmu\)g/L-17 \(\upmu\)g/L for FW-ZL and 5.4 \(\upmu\)g/L-8.7 \(\upmu\)g/L for FW-R), exceed the WHO standards required for pot  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Laundry ZL**} & \multicolumn{3}{c}{**Laundry R**} \\ \cline{2-8}
**Element (mg/L)** & **Goufia** & **Sludge Water** & **Recycled Water** & **Tarfaya** & **Sludge Water** & **Recycled Water** & **Regulation Limit 1** \\  & **(DW)** & **(SW)** & **(RW)** & **(DW)** & **(SW)** & **(RW)** & **(RW)** & \\ \hline F\({}^{-}\) & 2.37 & 4.7 & 2.32 & 1.9 & 0.77 & 1.28 & 1.5 \\
**NO\({}_{2}\)\({}^{-}\)** & 15.30 & -6.13 & 1.57 & 0.34 & 0.32 & -6.11 & 3 \\
**NO\({}_{3}\)\({}^{-}\)** & 17.70 & 48.6 & 17.15 & 32.74 & 32.88 & 32.94 & 50 \\
**PO\({}_{4}\)\({}^{3-}\)** & 14 & 24.8 & 15.40 & 22.2 & 33 & 23.6 & -4 \\
**SO\({}_{4}\)\({}^{2-}\)** & 1979 & 2570 & 2495 & 51.2 & 312.5 & 22.7 & 500 \\
**Element (ug/L)** & 1 & 14.14 & 5 & 1 & 6.12 & 1 & 3 \\
**Fe** & 10 & 10 & 10 & 10 & 10 & 10 & - \\
**Pb** & 2 & 1 & 2 & 4 & 2 & 3 & 10 \\
**Zn** & 19 & 53 & 21 & 20 & 66 & 14 & 3000 \\
**U** & n.a \({}^{2}\) & 1.58 & n.a & n.a & 3.13 & n.a & 15 \\ \hline \hline \end{tabular}  
* WHO standards for potable water, updated in 2006. \({}^{2}\) Not analyzed. \({}^{3}\) Below the detection limit. \({}^{4}\) No guide value.  
\end{table}
Table 4: Results of chemical analysis of drilling water (DW), sludge water (SW), and recycled water (RW) from M’Dhilla-Zone L (ZL) and Redeyef (R) laundries.  
Figure 4: Variation of **(a)** pH and **(b)** electrical conductivity (mS/cm) of the leachates during the seven cycles of the batch test (FW–R: fine waste in the sludge from Redeyer and FW–ZL: fine waste in the sludge from M’Dhilla-Zone L).  
Figure 5: Concentrations of Cd and U in the leachates of the seven batch cycles. **(a)** FW–ZL: fine waste from M’Dhilla-Zone L laundry and **(b)** FW–R: fine waste from Redeyer laundry.  
The percentages of Cd and U mobility in the solid fraction of the sludge, which are calculated from the ratio between the concentrations mobilized by the extractant (sludge water) to the total concentration of MTE, show that the mobility of both elements is low, with percentages not exceeding 0.067% and 0.014%, respectively, for M'Dhilla, and 0.028% and 0.016% for Redeyef.