## 3 Research Results and Their Analysis
Substantially higher sedimentation rates were observed under induced flocculation conditions using Flokor 1.2A (Figure 6b). Figure 5: Setup for real-time observation of algae sedimentation using the Dino-Lite AM7515 MT8A digital microscope (**a**); image of the settling _Chlorella vulgaris_ microalgae suspension with an initial concentration of 0.615 g/L, (magnification: 691\(\times\)) (**b**). The experimental data presented in Figure 6b indicate that the sedimentation rate ranged from 8.2 to 9.3 mm/min, depending on the concentration of the flocculant, which varied from 0.01 to 0.36 g/dm\({}^{3}\). For instance, with an initial algal concentration of 0.615 g/L, the sedimentation rate was 28-32 times higher than that observed under autoflocculation conditions, where the rate was only 0.29 mm/min. The application of Flokor 1.2A flocculant significantly reduced the sedimentation time. After approximately 15 min, the sedimentation dynamics slowed considerably, with the boundary between the clarified liquid and the flocculated algal suspension shifting very gradually. Continued gravitational sedimentation improved harvesting efficiency but required a much longer duration, approximately 120 min. By this time, the concentration of algae in the clarified liquid stabilized, ranging from 0.078 to 0.148 g/L, and a stable suspension formed. The changes in turbidity at various stages of sedimentation are shown in the photographs presented in Tables 2 and 3, which illustrate the differences in the sedimentation process of microalgae under autoflocculation and chemical flocculation conditions. Analysis of the images in Table 2, which show the turbidity levels under autoflocculation conditions, indicates that sedimentation efficiency is closely dependent on the initial algal concentration in the suspension. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sedimentation Time**} & \multicolumn{3}{c}{**Initial Algae Concentration in the Suspension \(C_{a,\theta}\) g/L**} \\ \cline{2-4}  & 0.375 g/L & 0.424 g/L & 0.511 g/L & 0.615 g/L \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Sedimentation of Baltic _Chlorella vulgaris_ BA-167 suspension at varying initial concentrations under autoflocculation conditions. Figure 6: Sedimentation curves of _Chlorella vulgaris_ BA-167: (**a**) under autoflocculation; (**b**) flocculation with Flokor 1.2A. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sedimentation Time**} & \multicolumn{3}{c}{**Initial Algae Concentration in the Suspension \(C_{a,0}\), g/L**} \\ \cline{2-4}  & 0.375 g/L & 0.424 g/L & 0.511 g/L & 0.615 g/L \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sedimentation Time**} & \multicolumn{3}{c}{**Concentration of Flokor 1.2A Floculant in an Algal Suspension with an Initial**} \\ \cline{2-4}  & **Concentration of 0.615 g/L** \\ \cline{2-4}  & **0.09 g/L** & **0.12 g/L** & **0.20 g/L** & **0.28 g/L** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Sedimentation of _Chlorella vulgaris_ BA-167 with Flokor 1.2A (initial algae concentration of 0.615 g/L). During the first 15 min of the process, a noticeable decrease in turbidity was observed, which resulted from a reduction in algal concentration. By comparing the turbidity changes over time, it was found that the highest sedimentation effect occurred at an initial algal concentration of 0.615 g/L, with sedimentation efficiency being less than 20%. Higher sedimentation efficiencies were achieved after conducting the process for 120 min, as shown in Figure 6.  
Figure 7 illustrates the changes in algal concentration in the clarified liquid during the gravitational sedimentation of algal suspensions with different initial concentrations (ranging from 0.375 to 1.740 g/L) under autoflocul  
Figure 7: Changes in the concentration of _Chloella vulgaris_ BA-167 over time during sedimentation under autoflocul conditions (**a**), and the corresponding harvesting efficiency (**b**).