## 3 Survey Results of the Use of Ornamental Flowering Plants in CWs  
Many CWs around the world used OFP for the removal of various types of wastewater (Table 1). For example, in China, the most popular plants used is _Canna_ sp., while in Mexico the ornamental plant used is more diverse, including plants with flowers of different colors, shapes and aromatic characteristics (_Canna_, _Heliconia_, _Zantedeschia_, _Strelitzia_ spp). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Country** & \begin{tabular}{c} **Type of** \\ **Wastewater** \\ \end{tabular} & **Vegetation** & \begin{tabular}{c} **Removal Efficiency of** \\ **Pollutants (\%)** \\ \end{tabular} & **Reference** \\ \hline Brazil & Domestic & _Heliconia spittacorum_ & TSS: 88, COD: 95, BOD: 95 & [PERSON] et al. [26] \\ \cline{2-5}  & Domestic & _Alpinia purpurataArandina_ & COD: 48-90, PO\({}_{4}\)-P: 20, TKN: 31 and TSS: 34. & [PERSON] et al. [27] \\ \cline{2-5}  & & _Heliconia spittacorum_ & \begin{tabular}{c} COD: 59, TP: 44, TKN: 34 and \\ NHx 35 \\ COP: 57, TP: 38, TKN: 34 and \\ NHx: 37 \\ \end{tabular} & \begin{tabular}{c} **Removal Efficiency of** \\ **Pollutants (\%)** \\ \end{tabular} & **Reference** \\ \hline Brazil & Domestic & _Heliconia spittacorum_ & TSS: 88, COD: 95, BOD: 95 & [PERSON] et al. [26] \\ \cline{2-5}  & Domestic & _Alpinia purpurataArandina_ & COD: 48-90, PO\({}_{4}\)-P: 20, TKN: 31 and TSS: 34. & [PERSON] et al. [27] \\ \cline{2-5}  & & _Heliconia spittacorum_ & \begin{tabular}{c} COD: 48-90, PO\({}_{4}\)-P: 20, TKN: 31 and TSS: 34. \\ \end{tabular} & [PERSON] et al. [27] \\ \cline{2-5}  & Swine & _Halydcium coronarium_ & \begin{tabular}{c} COD: 59, TP: 44, TKN: 34 and \\ NHx 35 \\ COP: 57, TP: 38, TKN: 34 and \\ NHx: 37 \\ \end{tabular} & [PERSON] et al. [28] \\ \cline{2-5}  & & _Heliconia spittacorum_ & \begin{tabular}{c} COD: 72, BOD: 90, TN: 52, TP: \\ 41 and SST: 72. \\ \end{tabular} & [PERSON] et al. [29] \\ \cline{2-5}  & & _Heliconia spittacorum_ & \begin{tabular}{c} [PERSON] et al. [30] \\ \end{tabular} \\ \hline China & Municipal & _Canna indica_ & COD: 77, BOD: 86, TP: \(>\)82, \\  & & TNi: \(>\)45 & \\ \cline{2-5}  & Aquaculture ponds & _Canna indica_ mixed with & BOD: 71, TNS: 82, \\  & other species & chlorophyll: \(\sim\)91, pH\({}_{4}\)-N: & [PERSON] et al. [32] \\ \cline{2-5}  & Domestic & _Canna indica_ Linn & COD: 82.31, BOD: 88.6, TP: \(>\)80, TN: \(>\)85 & [PERSON] et al. [33] \\ \cline{2-5}  & Municipal & _Canna indica_ & NH\({}_{4}\)-N: 99, PO\({}_{4}\)-P: 87 & [PERSON] et al. [34] \\ \cline{2-5}  & & _R. carnea, I. pseudacorns,_ & COD: 58-92, BOD: 60-90 & [PERSON] et al. [35] \\ \cline{2-5}  & factories & _L. salicaria_ & TN: 60-92, TP: 50-97, & [PERSON] et al. [35] \\ \hline River & _Canna_ sp & COD: 95, N-NH\({}_{4}\): 100, N-NO\({}_{3}\): 76, TN: 72 & [PERSON] et al. [36] \\ \cline{2-5}  & Domestic & _Canna indica_ & TP: 60, NH\({}_{4}\)-N: 30-70, TN: \(\sim\)25 & [PERSON] et al. [37] \\ \hline Aquaculture ponds & \
\begin{tabular}{c} _Canna indica_ mixed with \\ other natural wetland \\ plants \\ \end{tabular} &
\begin{tabular}{c} BOD: 56, COD: 26, TSS: 58, TP: \\ 17, TN: 48 and NH\({}_{4}\)-N: 34. \\ \end{tabular} & [PERSON] et al. [38] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Ornamental flowering plants and removal of wastewater pollutants in CWs (constructed wetlands) around the globe. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  
A review of the available literature showed that ornamental plants are used to remove pollutants from domestic, municipal, aquaculture ponds, industrial or farm wastewater. The removal efficiency of ornamental plants was also evaluated for the following parameters: biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), total phosphorous (TP), ammonium (NH\({}_{4}\)-N), nitrates (NO\({}_{3}\)-N), coliforms and some metals (Cu, Zn, Ni and Al).