## 3 Results and Discussion
### Organic Matter Development  
As shown in Figure 4, the OM degradation was most pronounced during the bio-oxidative composting phase, when temperatures were at their maximum values, with sets 2 and 4 showing the highest degradation during the first days of the process. The degradation of OM remained stable from about day 80 onwards. This demonstrates the microbial stability of the organic compounds in the final compost. The following parameter values (\(A\): maximum degradation; \(k\): rate constant; \(R^{2}\): coefficient of determination; standard deviation in parentheses; \(SEE\): standard error of estimate; and **: significant at \(p<0.01\)) were obtained by fitting the OM loss to a first-order kinetic equation:  
Set 1: \(A\) = 76.38 (0.02); \(k\) = 0.02 (0.005); \(R^{2}\) = 0.9900; \(F\) = 198.0 (**); \(SEE\) = 4.28  
Set 2: \(A\) = 77.89 (3.75); \(k\) = 0.05 (0.016); \(R^{2}\) = 0.9870; \(F\) = 151.3 (**); \(SEE\) = 5.26  
Set 3: \(A\) = 61.39 (4.66); \(k\) = 0.02 (0.006); \(R^{2}\) = 0.9828; \(F\) = 114.3 (**); \(SEE\) = 4.57  
Set 4: \(A\) = 62.13 (3.06); \(k\) = 0.05 (0.013); \(R^{2}\) = 0.9791; \(F\) = 141.5 (**); \(SEE\) = 4.30  
All of the equations were significant at \(p<0.01\). As can be seen from the values of \(F\), sets 1, 2, and 4 fit this equation better than set 3, which obtained the lowest value (114.3). The values obtained from the equations were slightly higher than those obtained by [PERSON] et al. [33] in a composting experiment with agri-food sludge and similar to those obtained \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Sample** & **pil** & **EC** & **OM** & **TN** & **TOC** & **TOC/TN** & **No** & **K** & **P** \\  & & **(458 \(\rightarrow\) 1)** & **(5)** & **(5)** & **(5)** & **(5)** & **(6)** & **(6)** & **(7)** & **(8)** \\ \hline  & & & & Set + \(\delta\)-EXEX, PWX + 19.05/CNW & & & & & \\ \hline M1 & 59\(\rightarrow\) 0.0 & 3.63\(\rightarrow\) 0.04 & 52.1\(\pm\) 0.27 & 209\(\rightarrow\) 0.03 & 443\(\rightarrow\) 0.4 & 21.3\(\pm\) 0.2 & 4.50\(\pm\) 0.05 & 11.3\(\pm\) 0.1 & 720\(\rightarrow\) 0.07 \\ M2 & 6.99\(\rightarrow\) 0.1 & 4.28\(\pm\) 0.29 & 84.5\(\pm\) 0.6 & 3.38\(\pm\) 0.02 & 50.4\(\pm\) 0.4 & 15.5\(\pm\) 0.1 & 3.55\(\pm\) 0.03 & 9.4\(\pm\) 0.08 & 52.3\(\pm\) 0.04 \\ M3 & 6.33\(\rightarrow\) 0.1 & 4.23\(\pm\) 0.04 & 82.6\(\pm\) 0.6 & 3.5\(\pm\) 0.03 & 44.3\(\pm\) 0.3 & 13.4\(\pm\) 0.1 & 4.77\(\pm\) 0.03 & 14.3\(\pm\) 0.1 & 6.0\(\pm\) 0.05 \\ M4 & 8.3\(\pm\) 0.2 & 4.35\(\pm\) 0.15 & 78.9\(\pm\) 0.27 & 35.5\(\pm\) 0.08 & 44.1\(\pm\) 0.1 & 22.6\(\pm\) 0.1 & 5.64\(\pm\) 0.06 & 15.0\(\pm\) 0.2 & 9.53\(\pm\) 0.10 \\ ISD & 0.3 & 0.25 & 1.2 & 0.07 & 1.0 & 0.3 & 0.1 & 0.3 & 0.18 \\ \hline \end{tabular}  
* M1: initial stage; M2: thermophilic stage; M3: end of bio-oxidative stage; M4: end of maturity. FW: food waste for different sets; CPW: campus pruning waste. EC: electrical conductivity; OM: total organic matter; TOC: total organic carbon; TN: total nitrogen. Data values reported as mean value \(\pm\) standard error. Average values in a column followed by the same letter are not significantly different at \(p<0.05\) (Tukey-b test). LSD: least significant difference at \(p<0.05\).  
\end{table} 
Table 4: _Cont._by [PERSON] et al. [34] with livestock waste. Comparing the values of \(A\), associated with the maximum degradation of OM, and of \(k\), related to the rate of the process, it can be observed that set 2 showed the highest values. This could be due to this set showing the greatest initial OM contents, probably more degradable than in set 1, which could be explained by the important heterogeneity of the food waste used in the mixtures. Conversely, set 3 showed the lowest \(A\) and \(k\) values and the worst fit of the model.