Table 6.
ANOVA statistical results of the response surface quadratic model for COD removal.
| Source | Sum of Squares | df | Mean Square | F-value | p-value | |
|---|---|---|---|---|---|---|
| Model (Quadratic) | 20.13 | 9 | 2.24 | 47.2 | <0.0001 | significant |
| A-PAC dosage | 0.5995 | 1 | 0.5995 | 12.65 | 0.0093 | |
| B-CPAM dosage | 4.9 | 1 | 4.9 | 103.38 | <0.0001 | |
| C-pH | 0.285 | 1 | 0.285 | 6.01 | 0.0439 | |
| AB | 6.71 | 1 | 6.71 | 141.57 | <0.0001 | |
| AC | 2.33 | 1 | 2.33 | 49.08 | 0.0002 | |
| BC | 1.74 | 1 | 1.74 | 36.77 | 0.0005 | |
| A2 | 0.326 | 1 | 0.326 | 6.88 | 0.0343 | |
| B2 | 3.12 | 1 | 3.12 | 65.83 | <0.0001 | |
| C2 | 0.0526 | 1 | 0.0526 | 1.11 | 0.3272 | |
| Residual | 0.3317 | 7 | 0.0474 | |||
| Lack of Fit | 0.0842 | 3 | 0.0281 | 0.4534 | 0.7291 | not significant |
| Pure Error | 0.2475 | 4 | 0.0619 | |||
| Corrected Total Sum of Squares | 20.46 | 16 | ||||
| Coefficient of variance (CV, %) | 0.23 | |||||
| R2 | 0.9838 | |||||
| Adjusted R2 | 0.9629 | |||||
| Predicted R2 | 0.9153 | |||||
| Adequate precision | 24.98 |