## 4 Results and Discussion  
The research results are presented in the form of graphs in Figures below. These charts demonstrate the analysis of the influence of each of the additives on the amount of water in the oil samples. Each sample of pure oil and oil with additives was tested three times. However, this article presents the average result for each case. Analyzing the obtained outcomes, it can be noted that in Figure 4, the water content of fresh oil with no EMs is 0.096%. The addition of 2.5 mL of microorganisms to the oil causes a considerable increase in the amount of water in the oil, because it is more than twice as high compared to oil without such an additive and amounts to 0.21% of the water content. With the addition of more microorganism solution, i.e., 5 mL, it was not possible \begin{table}
\begin{tabular}{l l} \hline \hline
**Parameters** & **Cou-Lo Aquamax KF Moisture Meter** \\ \hline Titration method & Coulometric Karl Fischer titration \\ Endpoint detection & AC polarity \\ Measurement range & 1 ug-10 mg of water, max 200 mg of water \\ Moisture range & 1 ppm-100\% water \\ Maximum titration rate & 2.24 mg per minute \\ Maximum electrolysis current & 400 mA \\ Drift Compensation & Controlled automatically \\ Minimum titration time & 0–30 min, user programmable \\ Precision & 10–100 ug \(\pm\) 3 ug, 100 ug-1 mg \(\pm\) 3 ug (ppm), over 1 mg \(\pm\) 0.3\% \\ Display format & \(\mu\)g mg/kg ppm, \% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Selected parameters of the Cou-Lo AquaMax KF automatic titrator. to determine the water content due to over-titration. It follows that this amount of water in oil was above 1%, i.e., above the measuring range of the device. The situation was different with the addition of ceramic tubes, wherein the microorganisms are bound and do not mix with the oil as in their liquid form. In Figure 4, we can see that the addition of microorganisms, especially in a smaller amount (3 pcs), reduced the water content in the oil, which is positive from an oil exploitation point of view, while the greater number of tubes does not affect the water content of the oil in any significant way. Figure 5 shows the color of the samples, and demonstrates that after adding microorganisms in a liquid form to the new oil, they became an oil-water emulsion and in this form were not suitable for use as a lubricating oil (there is probably some decomposition and release of water bound in the oil or a chemical reaction that resulted in the formation of such a large amount of water, which is related to the composition of the liquid additive of effective microorganisms). Silver compounds were also added to the new oil in amounts of 2.5 mL and 5 mL. In this case, it was not possible to read the results of the water content in the oil with the addition of both the first and the second type of silver for each amount, because after  
Figure 4: Water content in fresh oil and fresh oil with EMs in liquid form and ceramic tube form. Figure 5: Coloring of fresh oil, with the addition of effective microorganisms in liquid form and ceramic tube form. prolonged operation, the titrator showed over-titration, i.e., the water content in the oil exceeded the measuring range of the device. The mixtures of oil with the addition of silver solution and colloidal nanosilver are presented in Figure 6.  
These photos show that additives caused the formation of a water-oil emulsion. In this form, the lubricating oil will not properly perform the tasks for which it was intended. The milky appearance may be the outcome of Pickering emulsification [51; 52; 53], in which the bacteria and colloidal silver accumulate at the water-oil interface and prevent the water-in-oil droplets from coalescing. In the case of EMs, emulsification may also be caused by biosurfactants [54]. Figure 7 shows the flash point of fresh oil with the same additives as for the water content test. As in the case of the water content results, the best value of the flash point was obtained for three picks of ceramic-based effective microorganisms.