# Neutralization of Toxic Malodorous Gases from Cattle Slurry
## 3 Results
### Deodorization Effect of Cattle Slurry by Microorganisms
The highest ammonia reduction for the following strains: _Bacillus subtilis_ KKP 3903, and _Pseudomonas fluorescens_ KKP 3909 was observed. After the end of the process, the ammonia content was 1 ppm (KKP 3903) and 0 ppm (KKP 3909). The worst result was observed for _Pseudomonas_ \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Tested** **Strain**} & \multicolumn{6}{c}{**Ammonia reduction (\%)**} \\ \cline{2-11}  & \multicolumn{2}{c}{**After 2 Days**} & \multicolumn{2}{c}{**After 4 Days**} & \multicolumn{2}{c}{**After 6 Days**} & \multicolumn{2}{c}{**After 8 Days**} & \multicolumn{2}{c}{**After 10 Days**} \\ \cline{2-11}  & **R1** & **R2** & **R1** & **R2** & **R1** & **R2** & **R1** & **R2** & **R1** & **R2** \\ \hline KKP 3899 & 43\({}^{\circ}\pm 6\) & 62\({}^{\circ}\pm 4\) & 49\({}^{\circ}\pm 8\) & 72\({}^{\circ}\pm 4\) & 64\({}^{\circ}\pm 8\) & 84\({}^{\circ}\pm 4\) & 65\({}^{\circ}\pm 7\) & 91\({}^{\circ}\pm 2\) & 79\({}^{\circ}\pm 3\) & 95\({}^{\circ}\pm 1\) \\ KKP 3901 & 34\({}^{\circ}\pm 4\) & 56\({}^{\circ}\pm 8\) & 42\({}^{\circ}\pm 3\) & 68\({}^{\circ}\pm 5\) & 44\({}^{\circ}\pm 10\) & 74\({}^{\circ}\pm 3\) & 48\({}^{\circ}\pm 8\) & 84\({}^{\circ}\pm 3\) & 66\({}^{\circ}\pm 4\) & 91\({}^{\circ}\pm 1\) \\ KKP 3903 & 51\({}^{\circ}\pm 4\) & 68\({}^{\circ}\pm 3\) & 62\({}^{\circ}\pm 6\) & 79\({}^{\circ}\pm 12\) & 70\({}^{\circ}\pm 5\) & 86\({}^{\circ}\pm 2\) & 85\({}^{\circ}\pm 3\) & 96\({}^{\circ}\pm 2\) & 97\({}^{\circ}\pm 2\) & 99\({}^{\circ}\pm 0\) \\ KKP 3909 & 40\({}^{\circ}\pm 5\) & 60\({}^{\circ}\pm 4\) & 59\({}^{\circ}\pm 7\) & 77\({}^{\circ}\pm 4\) & 69\({}^{\circ}\pm 2\) & 86\({}^{\circ}\pm 5\) & 78\({}^{\circ}\pm 4\) & 94\({}^{\circ}\pm 1\) & 100\({}^{\circ}\pm 0\) & 100\({}^{\circ}\pm 0\) \\ KKP 3910 & 37\({}^{\circ}\pm 5\) & 58\({}^{\circ}\pm 8\) & 50\({}^{\circ}\pm 11\) & 72\({}^{\circ}\pm 5\) & 61\({}^{\circ}\pm 4\) & 82\({}^{\circ}\pm 3\) & 75\({}^{\circ}\pm 10\) & 93\({}^{\circ}\pm 3\) & 92\({}^{\circ}\pm 3\) & 98\({}^{\circ}\pm 1\) \\ KKP 3911 & 16\({}^{\circ}\pm 5\) & 44\({}^{\circ}\pm 3\) & 50\({}^{\circ}\pm 8\) & 25\({}^{\circ}\pm 8\) & 64\({}^{\circ}\pm 4\) & 34\({}^{\circ}\pm 6\) & 78\({}^{\circ}\pm 2\) & 47\({}^{\circ}\pm 2\) & 86\({}^{\circ}\pm 3\) \\ \hline \hline \end{tabular} Notes: The table shows mean values and standard deviations. Mean values designated by different letters are statistically significant at \(p<0.05\); \(n=3\). R1—reduction compared to the control sample; R2—reduction compared to the initial sample.  
\end{table} 
Table 4: The ammonia concentration reduction from CS during the deodorization process. Figure 2: The ammonia concentration in CS during the deodorization process. sp. (KKP 3911), where the reduction compared to the control sample (R1-reduction) was only 47% (20 ppm) on the tenth day of the deodorization process. All strains also effectively removed sulfur-containing compounds, the main odorant of which was H\({}_{2}\)S. The hydrogen sulfide concentration in the control sample was 113 ppm. The best results were obtained with _Bacillus subtilis_ (KKP 3903), and _Pseudomonas fluorescens_ (KKP 3909 and KKP 3910), which reduced H\({}_{2}\)S by 98-99% on Day 6, compared to the control sample (R1 reduction), as shown in Figure 3. It should be noted that in the case of the control experiment (without microbial supplementation), the removal of H\({}_{2}\)S reached 80% on Day 6 compared to the slurry before the deodorization process. On Day 10 of the process, this value exceeded 90%. On the other hand, the absolute value of H\({}_{2}\)S reduction obtained in the deodorization process for the above-mentioned microorganisms exceeded 100%, compared to the slurry before the deodorization process, as shown in Table 5.  
Based on the results, it was found that the highest H\({}_{2}\)S reduction was observed similarly to ammonia on Day 2 of the deodorization process.