## 3 Results  
### Coagulation-Flocculation in Continuous Mode  
#### 3.1.1 Color Removal  
In aquaculture effluents, color is often caused by dissolved organic matter [36], making it important to understand the relationship between these two parameters. As previously mentioned, four coagulants--two natural and two chemicals--were tested in a lab-scale continuous flow system to assess whether this type of setup could be integrated into the existing aquaculture treatment plant. The goal is to improve water quality and enhance fish visibility for both researchers and operators working in this aquaculture facility. Table 2 presents the color, NOM, and DOC removal efficiency in continuous mode. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Coagulant** & **pH** & \begin{tabular}{c} **Coagulant** \\ **Concentration (mg\(\cdot\)L\({}^{-1}\))** \\ \end{tabular} & \begin{tabular}{c} **DOC** \\ **Removal (\%)** \\ \end{tabular} & \
\begin{tabular}{c} **UV\({}_{254}\)** \\ **Removal (\%)** \\ \end{tabular} &
\begin{tabular}{c} **Color** \\ **Removal (\%)** \\ \end{tabular} \\ \hline \multirow{3}{*}{Al\({}_{2}\)(SO\({}_{4}\))\({}_{3}\).14H\({}_{2}\)O} & \multirow{3}{*}{6.5} & 20 & - & 12.06 \(\pm\) 0.02 & 33.5 \(\pm\) 0.2 \\  & & 50 & 45.4 \(\pm\) 0.5 & 28.00 \(\pm\) 0.01 & 48.8 \(\pm\) 0.4 \\  & & 100 & - & 53.62 \(\pm\) 0.01 & 62.4 \(\pm\) 0.2 \\ \cline{2-6}  & & 8 & 20 & 59.1 \(\pm\) 0.4 & 30.64 \(\pm\) 0.03 & 30.1 \(\pm\) 0.3 \\ \hline \multirow{3}{*}{FeCl\({}_{3}\).6H\({}_{2}\)O} & \multirow{3}{*}{6.5} & 20 & - & 16.00 \(\pm\) 0.01 & 40.3 \(\pm\) 0.2 \\  & & 50 & 44.4 \(\pm\) 0.6 & 51.89 \(\pm\) 0.01 & 47.8 \(\pm\) 0.2 \\  & & 100 & - & 55.93 \(\pm\) 0.01 & 70.9 \(\pm\) 0.5 \\ \cline{2-6}  & & 8 & 25 & 50.8 \(\pm\) 0.4 & 26.82 \(\pm\) 0.02 & 31.4 \(\pm\) 0.2 \\ \hline \multirow{3}{*}{Tanfloc} & \multirow{3}{*}{6.5} & 20 & - & 38.16 \(\pm\) 0.02 & 52.0 \(\pm\) 0.2 \\  & & 50 & 52.8 \(\pm\) 0.5 & 50.05 \(\pm\) 0.01 & 65.5 \(\pm\) 0.6 \\  & & 100 & - & 63.94 \(\pm\) 0.03 & 75.4 \(\pm\) 0.3 \\ \cline{2-6}  & & 7 & 25 & 66.2 \(\pm\) 0.4 & 29.87 \(\pm\) 0.02 & 45.9 \(\pm\) 0.5 \\ \hline \multirow{3}{*}{CS-based} & \multirow{3}{*}{6.5} & 20 & - & 20.90 \(\pm\) 0.03 & 42.5 \(\pm\) 0.4 \\  & & 50 & 31.7 \(\pm\) 0.3 & 53.42 \(\pm\) 0.01 & 61.0 \(\pm\) 0.3 \\  & & 100 & - & 64.45 \(\pm\) 0.01 & 62.3 \(\pm\) 0.2 \\ \cline{2-6}  & & 8 & 10 & 47.7 \(\pm\) 0.5 & 20.33 \(\pm\) 0.01 & 33.6 \(\pm\) 0.3 \\ \hline \end{tabular}
\end{table} 
Table 2: Comparison of coagulant efficiency on color, NOM, and DOC removal from aquaculture wastewater in continuous treatment mode. The results presented in Table 2 indicate that all coagulants effectively reduced the wastewater's initial color level. This is particularly important in the context of this study, as lowering the color enhances the ability to observe and take care of the fish more efficiently. In batch mode, chemical coagulants such as ferric chloride at a concentration of 75 mg\(\cdot\)L\({}^{-1}\) achieved a color reduction of approximately 95% [37], whereas, in this study's continuous mode system, a reduction of around 70% was observed at a concentration of 100 mg\(\cdot\)L\({}^{-1}\). At pH 8 and a concentration of 25 mg\(\cdot\)L\({}^{-1}\) of ferric chloride (under batch mode conditions), color removal was approximately 15% [14]--about half of what was achieved under continuous mode using the same operational conditions. The Al-based coagulant, which was ineffective in removing color during jar tests as demonstrated by [PERSON] et al. [14], showed the ability to reduce initial color levels in continuous mode, achieving over 60% color removal at a concentration of 100 mg\(\cdot\)L\({}^{-1}\) at natural pH. Although this coagulant is widely used, studies specifically addressing its effectiveness in color removal remain limited. Regarding the use of Tanfloc, results obtained at a concentration of 100 mg\(\cdot\)L\({}^{-1}\) in this study were comparable to those reported in the batch tests by [PERSON], et al. [37].