# Vermicomposting: A Valorization Alternative for Corn Cob Waste
## 3 Results and Discussion
### Vermicomposting Process
#### 3.2.5 Total Organic Carbon  
Figure 10 shows TOC behavior during the vermicomposting process. Initial values of 50.60%, 50.33%, 49.48% and 50.27% were observed for CR, M1, M2 and M3 respectively.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Physicochemical**} & \multicolumn{5}{c}{**At the Beginning**} & \multicolumn{5}{c}{**At the End**} \\ \cline{2-10} \multicolumn{1}{c}{**Parameters**} & **CR** & **M1** & **M2** & **M3** & **CR** & **M1** & **M2** & **M3** \\ \hline Total Nitrogen (\%) & 1.32 \(\pm\) 0.02 a & 1.28 \(\pm\) 0.04 a & 1.31 \(\pm\) 0.02 a & 1.31 \(\pm\) 0.06 a & 1.59 \(\pm\) 0.04 a & 1.60 \(\pm\) 0.06 a & 1.54 \(\pm\) 0.04 a & 1.52 \(\pm\) 0.04 a \\ Total Organic & 50.60 \(\pm\) 1.72 a & 50.33 \(\pm\) 0.91 a & 49.48 \(\pm\) 1.68 a & 50.27 \(\pm\) 0.75 a & 30.33 \(\pm\) 0.76 a & 30.03 \(\pm\) 0.78 a & 31.00 \(\pm\) 1.18 a & 32.71 \(\pm\) 0.98 b \\ Organic matter & 87.23 \(\pm\) 2.97 a & 86.77 \(\pm\) 2.34 a & 85.31 \(\pm\) 3.30 a & 86.67 \(\pm\) 2.77 a & 52.20 a & 51.70 a & 53.40 a,b & 56.40 b \\ C/N Relation & 38.48 \(\pm\) 1.08 a & 39.36 \(\pm\) 0.79 & 37.20 \(\pm\) 1.58 & 38.23 \(\pm\) 1.15 & 19.03 \(\pm\) 0.51 & 18.84 \(\pm\) 0.55 & 20.20 \(\pm\) 1.01 & 21.49 \(\pm\) 1.03 \\ Humidity (\%) & 75.50 \(\pm\) 1.51 & 79.40 \(\pm\) 2.54 & 79.36 \(\pm\) 1.76 & 77.19 \(\pm\) 1.70 & 58.46 \(\pm\) 1.64 & 50.84 \(\pm\) 1.58 & 66.43 \(\pm\) 1.99 & 58.65 \(\pm\) 1.10 \\ pH & 7.51 \(\pm\) 0.11 & 8.04 \(\pm\) 0.13 & 7.08 \(\pm\) 0.14 & 6.92 \(\pm\) 0.15 & 6.90 \(\pm\) 0.18 & 6.93 \(\pm\) 0.12 & 7.00 \(\pm\) 0.20 & 7.00 \(\pm\) 0.17 \\ \hline CR = Control reactor 50\% CCW-50\% LM; M1 = Reactor 50\% CCW-50\% LM; M2 = Reactor 60\% CCW-40\% LM and M3 = Reactor 40\% CCW-60\% LM. Mean values (mean \(\pm\) SD, \(\mu\) = 3), followed by different letters are statistically different (ANOVA; Tukey’s test, \(p\) \(<\) 0.05). & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Vermicomposting process physicochemical composition.  
Figure 9: Organic matter behavior in mixtures (CR, M1, M2 and M3) during the vermicomposting process.  
These values were similar to the 47.7% and 52.5% reported in vermicomposting processes for millet straw and sheep manure, and maize stover respectively [15,65].  
This figure shows TOC percentage decreased due to a carbon loss due to mineralization. The combined actions of the earthworms and microorganisms are responsible for TOC loss in CO\({}_{2}\) form in the residue [66].  
Final TOC values for mixtures CR, M1, M2 and M3 were 30.33%, 30.03%, 31.00% and 32.71% respectively, not unsimilar to the 29.2% and 33.2% in vermicomposting processes with vegetable solid waste and cow dung, as well as pulse bran, wheat straw and cow dung respectively [15,53].  
TOC removal efficiency levels shown by CR, M1, M2 and M3 were 40%, 40.29%, 37.34% and 34.84% respectively. The mixtures that showed a higher level of removal were CR and M1; their results were similar to another process reported using rice straw with an initial TOC value of 38.5% and a final of 27.6% [55].  
At the beginning of the vermicomposting process, TOC values were not significantly different between the four reactors, however, at the end of the process, there were statistically significant difference between M1 and M3 reactors (Table 2).