# Pre-Composting and Vermicomposting of Pineapple (_Ananas Comosus_) and Vegetable Waste
## 3 Results and Discussion
### Vermicomposting Process
#### 3.2.6 Total Nitrogen  
Initial concentrations for all four mixtures at the beginning of the vermicomposting process were 4.25% (CR) and (M1); 3.5% (M2) and 3.7% (M3) (Table 2), which coincided with various authors [32; 33; 59; 61; 62; 65]. At the end, concentrations were 1.5% (CR); 1.9% (M1); 1.2% (M2) and 2.2%  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameters** & **CR** & **M1** & **M2** & **M3** \\ \hline Organic matter (\%) & 57.89 \(\pm\) 0.61a & 57.89 \(\pm\) 0.61a & 51.46 \(\pm\) 0.94b & 52.84 \(\pm\) 0.84b \\ Total organic carbon (\%) & 33.58 \(\pm\) 0.36a & 33.58 \(\pm\) 0.36a & 29.85 \(\pm\) 0.55b & 30.65 \(\pm\) 0.49b \\ Total nitrogen (\%) & 4.25 \(\pm\) 0.08a & 4.25 \(\pm\) 0.09a & 3.5 \(\pm\) 0.06b & 3.7 \(\pm\) 0.08b \\ C/N relation & 7.9 & 7.9 & 8.53 & 8.28 \\ \hline \hline CR = Control reactor 50\%PW–50\%LM; M1 = Reactor 50\%PW–50\%LM; M2 = Reactor 60\%PW–40\%LM and M3 = Reactor 40\%PW–60\%LM. Mean values (mean \(\pm\) SD, \(n=3\)), followed by different letters are statistically different (analysis of variance (ANOVA); Tukey’s test, \(p<0.05\)). \\ \end{tabular}
\end{table}
Table 2: Characterization of the four pre-composed mixtures of pineapple waste and load material before vermicomposting.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter** & **CR** & **M1** & **M2** & **M3** \\ \hline Organic matter (\%) & 31.39 \(\pm\) 0.44a & 32.07 \(\pm\) 0.61a & 32.73 \(\pm\) 0.40a & 31.39 \(\pm\) 0.68a \\ Total organic carbon (\%) & 18.21 \(\pm\) 0.25a & 18.60 \(\pm\) 0.35a & 18.98 \(\pm\) 0.23a & 18.21 \(\pm\) 0.39a \\ Total nitrogen (\%) & 1.5 \(\pm\) 0.03a & 1.9 \(\pm\) 0.04b & 1.2 \(\pm\) 0.02c & 2.2 \(\pm\) 0.03d \\ C/N relation & 12.14 & 9.79 & 15.81 & 8.28 \\ \hline \hline \end{tabular}
\begin{tabular}{c} CR = Control reactor 50\%PW–50\%LM; M1 = Reactor 50\%PW–50\%LM; M2 = Reactor 60\%PW–40\%LM and M3 = Reactor 40\%PW–60\%LM. Mean values (mean \(\pm\) SD, \(n=3\)), followed by different letters are statistically different (ANOVA; Tukey’s test, \(p<0.05\)). \\ \end{tabular}
\end{table}
Table 3: Characterization of the four pineapple waste and load material mixtures after vermicomposting.  
(M3) (Table 3). The aforementioned concentrations were found to be within the range established by local norm for earthworm hummus from 1 to 4% [54]. Likewise, they are among the values from 1.2% and 4.2% obtained by multiple authors [32; 33; 59; 61; 62; 65; 67]. In all the mixes TN decreased, which was also reported by different authors [56; 62; 64]. This decrease in TN concentration was related to nutrient loss through the leachate as reported by [PERSON] et al. [15]. This TN decrease may also have presented itself due to the de-nitrification process that occurred within the earthworm's digestive tract [28] as well as ammonium volatilization [36]. According to the aforementioned data, removal percentages of TN during the vermicomposting process for all four mixes were 64.71% (CR); 55.29% (M1); 65.71% (M2) and 40.54% (M3). Initial concentrations of TN in the CR and M1 reactors presented significant differences in comparison to reactors M2 and M3, the final concentrations were significantly different between all four reactors. The highest value was M3 with a 2.2 + 0.03 concentration followed by M1 with 1.9 + 0.04.