## 3 Results
### Performance of CW Treating P. Radiata Leachate  
Table 2 shows the overall results of the CW unit operation with OLR ranging from 12 to 19 g COD/m\({}^{2}\)/day. A BOD\({}_{5}\) removal rate of 90 and 85% was found in the planted and unplanted CW units, respectively. The pH of the effluent reached maximum values between 7.3-7.4. Figure 2 shows the removal efficiency of the aromatic compounds at the different OLRs tested. The maximum removal efficiency of aromatic compounds (UV\({}_{254\mathrm{nm}}\)) was approximately 70% and was detected at the OLR of 13 g COD/m\({}^{2}\)/day. At the highest OLR of 19 g COD/m\({}^{2}\)/day, the efficiency was decreased 50-60% and the absorbance value was \(0.67\pm 0.26\) and \(0.57\pm 0.27\) for the planted and unplanted CW, respectively (Table 2). Similar behavior was observed for lignin-derived compounds measured at wavelengths of 280 and 272 nm with respective maximum removals of 60% and 70% for an OLR of 13 g COD/m\({}^{2}\)/day. At the OLR of 19 g COD/m\({}^{2}\)/day, the removal efficiency dropped to 50% and 60%, respectively. Similar behavior was also found for the lignocellulosic acids (Figure 2). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter** & **Unit** & **Phase** & \begin{tabular}{c} _E. Globulus_ \\ **Leachate** \\ \end{tabular} & \begin{tabular}{c} _P. Radiata_ \\ **Leachate** \\ \end{tabular} \\ \hline \multirow{3}{*}{pH} & - & I & \(6.58\pm 0.48\) & \(6.69\pm 0.63\) \\  & - & II & \(6.32\pm 0.71\) & \(6.45\pm 0.55\) \\  & - & III & \(5.21\pm 0.48\) & \(5.85\pm 0.29\) \\ \hline \multirow{3}{*}{BOD\({}_{5}\)} & \multirow{3}{*}{mg/L} & I & n.d. & n.d. \\  & & II & \(144.00\pm 0.00\) & \(78.50\pm 0.00\) \\  & & III & \(216.00\pm 0.00\) & \(104.00\pm 0.00\) \\ \hline \multirow{3}{*}{COD} & \multirow{3}{*}{mg/L} & I & \(271.70\pm 24.79\) & \(236.80\pm 18.52\) \\  & & II & \(500.05\pm 93.25\) & \(253.80\pm 39.04\) \\  & & III & \(832.80\pm 88.38\) & \(341.40\pm 67.44\) \\ \hline \multirow{3}{*}{\begin{tabular}{c} Aromatic compounds \\ (UV\({}_{254\mathrm{nm}}\)) \\ \end{tabular} } & \multirow{3}{*}{Absorbance} & I & \(3.35\pm 0.40\) & \(0.92\pm 0.16\) \\  & & II & \(7.74\pm 1.77\) & \(0.97\pm 0.17\) \\  & & III & \(12.26\pm 0.17\) & \(1.41\pm 0.71\) \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Lignin derived \\ compounds (UV\({}_{280\mathrm{nm}}\)) \\ \end{tabular} } & \multirow{3}{*}{Absorbance} & I & \(2.81\pm 0.21\) & \(0.80\pm 0.14\) \\  & & II & \(6.51\pm 1.42\) & \(0.86\pm 0.11\) \\  & & III & \(10.44\pm 0.37\) & \(1.29\pm 0.69\) \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Lignosulphonic acids \\ (UV\({}_{346\mathrm{nm}}\)) \\ \end{tabular} } & \multirow{3}{*}{Absorbance} & I & \(1.02\pm 0.17\) & \(0.28\pm 0.06\) \\  & & II & \(2.07\pm 0.29\) & \(0.35\pm 0.04\) \\ \cline{1-1}  & & III & \(4.08\pm 0.65\) & \(0.56\pm 0.43\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Physico-chemical characteristics of the _P. radiata_ and _E. globulus_ leachates. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multirow{2}{*}{**Unit**} & \multirow{2}{*}{**Phase**} & \multicolumn{2}{c}{_E. Globulus_ **Leachate**} & \multicolumn{2}{c}{_P.