# Thermo-Chemical Treatment for Carass Disposal and the Application of Treated Carcass as Compost
## 3 Results and Discussion
### Comparison of Thermo-Chemical Treatment Machinery with Conventional Methods  
Thermo-chemical treatment of carcasses is considered to be superior to other existing methods, both in terms of cost, processing time, and effectiveness. Dumping in open pits has been the most widely used method for disposal of carcasses in Korea, because Korean law requires disposal of dead livestock within 24 h to prevent the spread of infectious diseases [12]. However, burial/open pit disposal of carcasses can cause groundwater contamination via seepage, and hence the spread of disease-causing organisms. Another option for carcass disposal suggested by the Korean government is incineration, but its application has been limited because of the risk of spread of infectious diseases during transportation and backlogs owing to insufficient incinerator capacity [3]. Incineration also involves high running costs (including labor) and generates offensive odors and air pollution [26]. In recent years, rendering processes have proven advantageous because the production process is safe and can be used for an additive for animal feeding because of the high protein content. However, the rendering process is costly and energy-intensive; it can furthermore lead to the spread of pathogenic microorganisms during transportation of carcasses to rendering plants [27; 28]. For the current study, since the thermo-chemical treatment method was carried out at a lower temperature than required for incineration, the residence time was brief and processing speed was rapid. It was determined that the thermo-chemical treatment method can be conducted faster than other methods (apart from burial). While it required 10 days to treat 418 pigs using thermo-chemical treatment machinery, for incineration, rendering, and anaerobic digestion processes it would take more than 20 days. As described in Section 3.2, dioxins and VOCs that are commonly emitted during incineration were not detected or were observed to be below the acceptable limit. Despite the rapid treatment, no biohazards such as _E. coli_ and _Salmonella_ were detected on carcasses treated using the mechanized thermo-chemical treatment process. Another advantage of the latter process is that having the equipment affixed to a truck provides the mobility to treat carcasses on site. This can reduce the risk of spread of disease from transporting infected carcasses. The \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Analysis** & **Regulation** & **Chicken/No Quicklime** & **Chickens/Quicklime** & **Pigs/No Quicklime** & **Pigs/Quicklime** \\ \hline N (\%) & & 0.74 & 0.80 & 0.91 & 1.00 \\ P\({}_{2}\)O\({}_{5}\) (\%) & & 0.27 & 0.34 & 0.30 & 0.38 \\ K (\%) & & 0.29 & 0.32 & 0.33 & 0.34 \\ C (\%) & \textless{}12 & 22.7 & 24.3 & 37.3 & 38.3 \\ Organic matter to & \textgreater{}45 & 30.7 & 30.4 & 41.0 & 38.2 \\ nitrogen ratio & \textgreater{}85 & 27.91 & 15.58 & 10.64 & 10.21 \\ Moisture (\%) & \textgreater{}2 & 0.00015 & 0.0076 & 0.004 & 0.0074 \\ Hg (mg/kg) & \textgreater{}45 & 2.4 & 1.82 & 1.98 & 1.56 \\ Cd (mg/kg) & \textgreater{}5 & 0.12 & 0.12 & 0.12 & 0.16 \\ Pb (mg/kg) & \textgreater{}130 & 3.77 & 2.95 & 2.89 & 2.65 \\ Cu (mg/kg) & \textgreater{}360 & 5.79 & 5.21 & 9.71 & 10.54 \\ Ni (mg/kg) & \textgreater{}45 & 2.19 & 1.86 & 5.15 & 2.78 \\ Zn (mg/kg) & \textgreater{}900 & 30.88 & 24.77 & 60.5 & 61.28 \\ Cr (mg/kg) & \textgreater{}200 & 4.1 & 3.2 & 11.46 & 4.27 \\ Salinity (\%) & \textgreater{}2 & 0.22 & 0.23 & 0.23 & 0.24 \\ Germination index & \textless{}70 & 30.98 & 19.74 & 24.27 & 17.83 \\ Alkali fraction (\%) & & 16.07 & 25.18 & 12.7 & 25.51 \\ _Escherichia coli_ & N.D \({}^{\dagger}\). & N.D. & N.D. & N.D. & N.D. \\ (O157:H7) & N.D. & N.D. & N.D. & N.D. & N.D. \\ _Salmonella_ & N.D. & N.D. & N.D. & N.D. & N.D. \\ \hline \hline \end{tabular} \({}^{\dagger}\) N.D. Not detected.  
\end{table} 
Table 1: Chemical properties of thermos-chemically treated carcass of chicken and pigs with Korean standard regulation for compost use.