## 4 Discussion  
### Filtration of Total Count Bacteria  
Removal of bacteria from water was demonstrated by filtration based on adsorption of the bacteria by micelle-clay complexes [12; 13; 15; 25; 26; 27; 28] and by polymer-clay composites [29; 30]. In parallel, biostatic and/or biocidal effects on bacteria by several quaternary amine cations were demonstrated [19; 31]. The mechanistic suggestion that the release of an organic cation, such as ODTMA, during filtration can enhance the capacity of the filter in removal of bacteria from water was emphasized in [13; 15; 32; 33; 34]. The results in [12; 13; 14] contributed to the notion that the release of ODTMA cations during filtration from an  
Figure 3: Eluted fractions of alachlor and its modeling in filtration experiments including clay–DDAB complexes. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & \multicolumn{3}{c}{**Metolachlor, Micelle–Clay**} & \\ \hline
**Ro (M)** & **C\({}_{1}\) (M\({}^{-1}\) min\({}^{-1}\))** & **D\({}_{1}\) (min\({}^{-1}\))** & **K (M\({}^{-1}\))** & **Ro \(\cdot\)K** & **R\({}^{2}\)** & **RMSE** \\ \hline
0.042 & 30 & 4\(\cdot\)10\({}^{-4}\) & 7.5\(\cdot\)10\({}^{4}\) & 3150 & 0.97 & 1.8 \\ \hline  & & \multicolumn{3}{c}{**Alachlor, liposome–clay**} & \\ \hline Ro (M) & C\({}_{1}\) (M\({}^{-1}\) min\({}^{-1}\)) & D\({}_{1}\) (min\({}^{-1}\)) & K (M\({}^{-1}\)) & Ro\(\cdot\)K & R\({}^{2}\) & RMSE \\ \hline
0.15 & 20 & 1.1\(\cdot\)10\({}^{-3}\) & 1.8\(\cdot\)10\({}^{4}\) & 2700 & 0.98 & 0.02 \\ \hline \end{tabular}
\end{table} 
Table 5: Calculated parameters by the adsorption–convection model for the fit of experimental data of metolachlor and alachlor filtration by ODTMA– and DDAB-clay composites. enriched granulated complex would exceed the release from an ordinary complex. The results in Tables 1-3 demonstrate that granulated micelle-clay complexes with larger ratios of ODTMA cations to the clay were more efficient in removal of total count bacteria from drinking water, in line with the hypothesis put forward in the Introduction section. It is of interest to examine in some detail the excessive numbers of bacteria reported in Table 1 in the samples taken in the morning, compared with those after 3 h of filtration. It is noted that water pores comprise about 45% of the volume of a filter, which contains granulated ODTMA-bentonite in addition to a certain water layer at the upper hand of the filter. In the initial stages of filtration in the current experiments (after 2 days, Table 1, Wednesday), only a few bacteria were found emerging through all the filters, but eventually, the pores in the filters included free bacteria, which could reproduce during halted filtration for 20 h on Wednesday afternoon or for 67 h from Thursday afternoon until Sunday morning. The numbers of bacteria emerging through the filters were larger in the respective samples taken from one of the columns filled with the ordinary complex. On Sunday afternoon the numbers of TBC emerging were small again. However, the numbers of bacteria emerging from the filters with enriched complex remained small during the whole experiment due to the larger numbers of released ODTMA cations, which exerted biodidal/biostatic effects. The results in Table 1 indicate that the volume which could be filtered with emerging bacteria below 1000 TBC/mL through a column including the enriched complex was larger than 1630 L since the samples taken in the morning and afternoon of the last day gave small average numbers of emerging bacteria, 35 and 0 per mL, respectively. The capacity deduced for the enriched granular complex (Table 1) is larger than 1630 L/550 g, which yields 3 L/g, in comparison with 2 L/g deduced from the results in Table 3. It is remarkable that the flow velocity was 10-fold larger in the experiment represented by Table 1 than that reported in Table 3. Previous experiments on removal of chemicals from drinking water in [12] or _E.