## 3 Results and Discussion  
### Characterization of the Synthetic Greywater  
The physical and chemical characteristics of the SGW that fed the CW are presented in Table 1.  
The average concentration of organic matter in terms of COD in the greywater was 843.7 mg/L, which is intermediate compared to the range of 22.9 to 1307 mg/L reported by [PERSON] and [PERSON] [11], with higher values linked to excessive use of cleaning chemicals and food residues [12]. The average TDS of 700 mg/L and EC of 1430.0 \(\upmu\)S/cm were higher than the maximum values reported by [PERSON] et al. [12], which were 650.0 mg/L and 650.0 \(\upmu\)S/cm, respectively. This increase is likely due to the water used in preparing the synthetic greywater, similar to [PERSON] [13], who observed an average EC of 3280.0 \(\upmu\)S/cm, attributed to the use of groundwater, which generally has higher salt concentrations [14].  
The concentration of nitrate in the greywater was relatively low, at 3.4 mg/L, compared to 8.9 mg/L reported by [PERSON] and [PERSON] [8]. In contrast, ammoniacal nitrogen was higher, 20.0 mg/L, significantly exceeding the 0.4 mg/L found by those authors. The level obtained is more consistent with the values reported by [PERSON] et al. [15] (<14.0 mg/L), as higher nitrogen concentrations are typically associated with dark greywater from kitchen sinks [15; 16]. The phosphorus concentration in the greywater was (35.3 \(\pm\) 4.4) mg/L, which is within the reported range of 0.062-57 mg/L [15]. This variation is influenced by the intensity of detergent, soap, and other cleaning products containing phosphates used in kitchens, bathrooms, and laundries [15; 16]. The pH values of greywater generally range from over 9.0, due to heavy use of cleaning products, to between 6.0 and 8.2, due to the  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Parameter** & **Minimum** & **Maximum** & **Average** \\ \hline pH & 6.61 & 7.11 & 6.83 \(\pm\) 0.20 \\ \hline EC (\(\upmu\)S/cm) & 1256.0 & 1452.0 & 1430.0 \(\pm\) 60.4 \\ \hline Hardness (mgCaCoO\({}_{3}\)/L) & 100.0 & 175.0 & 135.7 \(\pm\) 23.5 \\ \hline COD (mg/L) & 713.7 & 1030.0 & 843.7 \(\pm\) 95.0 \\ \hline Phosphorus (mg/L) & 29.6 & 39.8 & 35.3 \(\pm\) 3.4 \\ \hline Ammonium (mg/L) & 9.7 & 33.8 & 20.5 \(\pm\) 6.4 \\ \hline Nitrate (mg/L) & 2.8 & 4.1 & 3.4 \(\pm\) 0.5 \\ \hline Nitrite (mg/L) & 51.5 & 60.3 & 57.7 \(\pm\) 2.6 \\ \hline LAS (mg/L) & 3.4 & 6.1 & 4.3 \(\pm\) 0.9 \\ \hline DO (mg/L) & 1.2 & 3.1 & 1.9 \(\pm\) 0.5 \\ \hline TS (mg/L) & 1360 & 1614 & 1498 \(\pm\) 82 \\ \hline TDS (mg/L) & 628 & 736 & 700 \(\pm\) 32 \\ \hline TSS (mg/L) & 640 & 897 & 751 \(\pm\) 80 \\ \hline \hline \end{tabular} EC—electrical conductivity; COD—chemical oxygen demand; LAS—linear alkylbenzene sulfonate; DO—dissolved oxygen; TS—total solids; TDS—total dissolved solids; TSS—total suspended solids.  
\end{table}
Table 1: Characterization of the greywater that fed the constructed wetland.  
presence of amino acids [16; 17]. The average pH in this study was (6.83 \(\pm\) 0.20), consistent with the typical range for such discharges.  
Products like laundry detergents, dishwashing detergents, and fabric softeners contribute to the presence of anionic surfactants in wastewater, with LAS being the most commonly used in these formulations, accounting for an annual global production of 4 million tons [18]. When these discharges are not properly managed, LAS can become adsorbed onto suspended particles and sediment in water bodies [19].