# A Preliminary Study on the Use of Xylit as Filter Material for Domestic Wastewater Treatment
## 3 Results and Discussion
### Efficiency of Wastewater Quality Indicators Removal
#### 3.2.5 Total Suspended Solids  
The average values of inflow TSS at preliminary stage and stage I were as follows: 387.6 \(\pm\) 73.5 mg/L (\(n\) = 9) and 107.3 \(\pm\) 19.7 mg/L (\(n\) = 4), respectively (Tables 8 and 9). The average efficiencies of TSS removal at the preliminary stage were 42.1 \(\pm\) 6.2% (\(n\) = 9) for angel hair (AH), and 70.2 \(\pm\) 8.1% (\(n\) = 8, excluding the measurement of 2 July 2019, as a rough measurement error) for crushed material (SCR). The details related to TSS removal efficiencies at this stage are presented in Figure 10. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample No.**} & \multirow{2}{*}{**Inlet**} & \multicolumn{2}{c}{**AH**} & \multicolumn{2}{c}{**SCR**} \\ \cline{3-7}  & & **Outlet** & **Efficiency** & **Outlet** & **Efficiency** \\ \cline{2-7}  & **mg/L** & **mg/L** & **\%** & **mg/L** & **\%** \\ \hline
1 & 654.2 & 129.60 & 80.2 & 654.2 & 24.20 \\
2 & 218 & 142.00 & 34.9 & 218 & 17.60 \\
3 & 348.9 & 283.10 & 18.9 & 348.9 & 202.00 \\
4 & 343.9 & 247.40 & 28.1 & 343.9 & 13.50 \\
5 & 351.9 & 210.30 & 40.2 & 351.9 & 109.50 \\
6 & 642.8 & 318.00 & 50.5 & 642.8 & 375.00 \\
7 & 665.1 & 313.00 & 52.9 & 665.1 & 208.80 \\
8 & 57.7 & 43.40 & 24.8 & 57.7 & 184.80 \\
9 & 205.5 & 105.60 & 48.6 & 205.5 & 90.60 \\ \hline Avg. & 387.6 \(\pm\) 73.5 & 199.2 \(\pm\) 32.9 & 42.1 \(\pm\) 6.2 & 387.6 \(\pm\) 73.5 & 136.2 \(\pm\) 39.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Inlet and outlet TSS and removal efficiencies at preliminary stage. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample No.**} & \multirow{2}{*}{**Inlet**} & \multicolumn{2}{c}{**AH**} & \multicolumn{2}{c}{**SCR**} \\ \cline{3-7}  & & **Outlet** & **Efficiency** & **Inlet** & **Outlet** & **Efficiency** & **Inlet** & **Outlet** & **Efficiency** \\ \cline{2-7}  & **mg/L** & **mg/L** & **\%** & **mg/L** & **mg/L** & **\%** & **mg/L** & **mg/L** & **\%** \\ \hline
1 & 66 & 7.30 & 88.9 & 66 & 5.2 & 92.1 & 66 & 21.70 & 67.1 \\
2 & 82.2 & E. & n. d. & 82.2 & 9.2 & 88.8 & 82.2 & 25.90 & 68.5 \\
3 & 132.9 & 63.20 & 52.4 & 132.9 & E. & n. d. & 132.9 & 22.40 & 83.1 \\
4 & 148.1 & 127.30 & 14.0 & 148.1 & 9.4 & 93.7 & 148.1 & 13.80 & 90.7 \\ \hline Avg. & 107.3 \(\pm\) 19.7 & 65.9 \(\pm\) 34.7 & 51.8 \(\pm\) 21.6 & 107.3 \(\pm\) 19.7 & 7.9 \(\pm\) 1.4 & 91.5 \(\pm\) 1.4 & 107.3 \(\pm\) 19.7 & 21.0 \(\pm\) 2.6 & 77.4 \(\pm\) 5.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Inlet and outlet TSS and removal efficiencies at stage I. The average efficiencies of TSS removal efficiency at stage I were highly variable (14.0%-93.7%). The average TSS removal efficiencies were also differentiated--on average for AH1, was 51.8 \(\pm\) 21.6% (\(n\) = 3), for AH, 91.5 \(\pm\) 1.4% (\(n\) = 3), and for SCR, 77.4 \(\pm\) 5.7% (\(n\) = 4). The details related to TSS removal efficiencies at stage I are presented in Figure 11.  
During the preliminary experiment, some anomalies related to inlet TSS concentrations were observed. Although no flow-rate-related problems were identified, these phenomena could be the result of dosing tubes clogging by suspended solids or other unknown phenomena. During stages I and II, the dosing tubes were controlled (and shaken) to prevent clogging. The average efficiencies of total suspended solid removal were not identified at stage II, and it was concluded from the preliminary stage and stage I that this indicator concentration is highly changeable due to the potential excess biomass detachment. Some amounts of suspended solids in the filter effluent are rather unavoidable due to the activity, growth, and detachment of some of the excessive biomass inhabiting the filter. The increase in con  
Figure 11: Inlet and outlet TSS and removal efficiencies at stage I.  
Figure 10: Inlet and outlet TSS and removal efficiencies at preliminary stage. centration and increased instability of total suspended solids in the effluent may also have been influenced by the development of _Psychoda_ flies, which were observed periodically.