## 3 Results and Discussion
In contrast, the dissolution of the lime in the calcareous granular material in the control treatment kept the concentrations of the Ca+Mg in the leachate relatively high and quite constant, with an average value of \(\sim\)7.5 mg L\({}^{-1}\) along the consecutive rainstorms (Figure 3A,B). For the TWW and brine treatments, in the beginning of the first rainstorms (Figures 1-3) the concentrations of the ions (Cl, Na, and Ca+Mg) in the leachate were higher than in the control treatment. These high concentrations were a result of the previous applications of the TWW and brine solutions on the granular materials. However, these high concentrations of Cl, Na, and Ca+Mg decreased sharply with the cumulative rainfall, and near the end of the last rainstorm, the concentrations of these ions were similar to their corresponding concentrations in the control treatment (Figures 1-3). Figure 2: Na\({}^{+}\) concentrations in the outflow leachate from the trays with treated granular materials as functions of the cumulative rainfall of the 1 st (**A**) and 3 rd (**B**) consecutive rainstorms for the control, of the 1 st (**C**) and 3 rd (**D**) consecutive rainstorms for the treated wastewater (TWW) treatments, and of the 1 st (**E**) and 6 th (**F**) consecutive rainstorms for the brine treatment. Vertical lines near the symbols are standard deviations (the Y-axes’ scales are different). According to the rainfall simulator results (Figures 1-3), for each studied ion and treatment solution the total leaching amounts (\(\ell_{j}\)) of ion \(j\) (Cl, Na, or Ca+Mg) from the treated granular material during the consecutive rainstorms, as a percentage of the total added amount of ion \(j\) by the treatment solution, were calculated by Equation (1):  
\[\centering\xi_{j}=(\frac{\sum_{k=1}^{k=m}(\sum_{i=1}^{i=n}(Vd_{i}\cdot Cd_{i})- \sum_{i=1}^{i=n}(Vc_{i}\cdot Cd_{i}))}{L\cdot S_{j}})\cdot 100\@add@centering \tag{1}\]  
where \(k\) is the consecutive serial number of the consecutive rainstorm; \(Vd_{i}\) and \(Cd_{i}\) are the leachate volumes (L m\({}^{-2}\)) and concentrations (gr L\({}^{-1}\)) of ion \(j\), respectively, for brine or TWW applications; and the \(Vc_{i}\) and \(Cc_{i}\) are the leachate volumes (L m\({}^{-2}\)) and concentrations (gr L\({}^{-1}\)) of ion \(j\), respectively, for the control treatment, when I is the consecutive serial number of the rainfall fractions in each consecutive rainstorm. \(S_{j}\) is the amount of ion \(j\) (mg m\({}^{-2}\)) added to the granular material with each application event of the brine or TWW, when \(L\) is the total number of the application events. For determining the \(\ell_{j}\) values for brine treatment by Equation (1), the values of \(Vc_{i}\) and \(Cc_{i}\) of the fourth, fifth and sixth consecutive rainstorms in the control treatment were, most likely, equal, corresponding with the values of the third rainstorm in the control treatment (Figures 1A-3A). This is because the values of \(Vc_{i}\) and \(Cc_{i}\) at the third rainstorm in the control treatment reached steady state values (Figures 1A-3A). The \(\ell_{j}\) values for Cl, Na, and Ca+Mg ions indicated that >99.5% of the amounts of these ions added onto the granular material by the WWT or brine solutions were reached down during the rainstorms. These results strengthen the previous observation that the  
Figure 3: Ca+Mg concentrations in the outflow leachate from the trays with treated granular materials as functions of the cumulative rainfall of the 1 st (**A**) and 3 rd (**B**) consecutive rainstorms for the control, of the 1 st (**C**) and 3 rd (**D**) consecutive rainstorms for the treated wastewater (TWW) treatment, and of the 1 st (**E**) and 6 th (**F**) consecutive rainstorms for the brine treatment. Vertical lines near the symbols are standard deviations (the Y-axes’ scales are different). calcareous granular material has a negligible capacity to adsorb the studied ions, and to prevent their vertical movement.