# Neutralization of Toxic Malodorous Gases from Cattle Slurry
## 4 Discussion  
A literature review showed that the new chemical and physical methods of neutralizing malodorous gases, despite their high odor removal efficiency, have a high cost for equipment, may require the use of chemicals, and also the processes are less environmentally friendly than microbiological neutralization. In most of the scientific studies analyzing the biological methods for odor treatment, the use of pig and chicken manure was dominant. There are few literature reports presenting the deodorization of cattle slurry. It is predicted that cattle farms will continue to grow and consequently, ecological issues related to slurry management will increase. Therefore, improving the fertilizer value of the slurry is an important aspect for farmers. As presented in the publication, the use of a microbial consortium limits the loss of ammonium ions (increasing nitrogen bioavailability in the slurry) and enhances the accessibility of macro-elements, which can be used for agricultural production. The presence of ammonium nitrogen (NH\({}_{4}\)-N) in slurry ensures greater nitrogen absorption by plants, which can take it up directly and incorporate it into organic compounds. The slurry will serve as a significant source of nutrients and organic matter for enhancing soil fertility. Consequently, the organic fertilizer will possess greater value, as it will retain more nitrogen, potentially reducing the demand for mineral fertilizers and the need for repeated applications to sustain soil fertility. It was found that the application of microbial biopreparation offers several benefits, including a short deodorization process time, no pollutants, adsorption of heavy metal compounds, and increased concentration of macro-elements. Furthermore, it will enhance the processes associated with slurry management and improve its physicochemical properties, such as increased homogeneity and liquefaction. Slurry with a uniform density is more valuable, as it ensures the consistent distribution of nutrients into the soil during field application. The application of biopreparation will reduce the formation of a crust on the slurry surface and facilitate its preliminary homogenization, thereby decreasing operational costs by reducing the need for prolonged mechanical agitation. The developed bacterial consortium will be able to direct application to slurry and use in litter-less cowsheds on both individual and industrial farms. The application of microbial preparation for slurry treatment is consistent with innovative methods for modernizing livestock barns towards the implementation of technologies designed to reduce malodorous \begin{table}
\begin{tabular}{c c c} \hline \hline
**Element** & **Control CS** & **Biotreated CS** \\  & **[mg/kg Dry Matter]** & **[mg/kg Dry Matter]** \\ \hline Zinc (Zn) & 27.34 \(\pm\) 0.19 & 24.96 \(\pm\) 0.16 \\ Iron (Fe) & 58.00 \(\pm\) 0.16 & 44.75 \(\pm\) 0.023 \\ Copper (Cu) & 74.20 \(\pm\) 0.52 & 57.11 \(\pm\) 0.19 \\ Manganese (Mn) & 19.80 \(\pm\) 0.11 & 20.28 \(\pm\) 0.12 \\olybdenum (Mo) & 1.20 \(\pm\) 0.07 & 1.12 \(\pm\) 0.04 \\ Lead (Pb) & 7.12 \(\pm\) 0.14 & 6.51 \(\pm\) 0.08 \\ Chromium (Cr) & 13.52 \(\pm\) 0.06 & 11.46 \(\pm\) 0.16 \\ Nickel (Ni) & 4.98 \(\pm\) 0.05 & 4.04 \(\pm\) 0.04 \\ Caluminum (Cd) & 10.86 \(\pm\) 0.09 & 9.05 \(\pm\) 0.11 \\ Boron (B) & 3.19 \(\pm\) 0.03 & 3.61 \(\pm\) 0.03 \\ \hline \hline \end{tabular} Notes: The table shows mean values and standard deviations. Samples were analyzed in triplicate.  
\end{table} 
Table 8: Content of heavy metals in CS after the deodorization process by bacterial consortium (_Bacillus subtilis_ KKP 3903 and _Pseudomonas fluorescens_ KKP 3909, 1:1). gas emissions. It will help reduce odor nuisance in rural areas, where slurry is applied to fields. Microbial deodorization of slurry will contribute to a positive environmental impact by mitigating the emission of toxic gases and reducing dependence on synthetic nitrogen fertilizers.