Table 4.
Analysis of variance (ANOVA) for COD, total suspended solids (TSS), color and NH3–N removals.
| Source | Sum of Squares | DF | Mean Square | F Value | Prob > F | |
| COD Removal (%) | Model | 2650.63 | 5 | 530.13 | 103.36 | <0.0001 |
| A | 1414.38 | 1 | 1414.38 | 275.77 | <0.0001 | |
| B | 767.20 | 1 | 767.20 | 149.59 | <0.0001 | |
| A2 | 77.79 | 1 | 77.79 | 15.17 | 0.0059 | |
| B2 | 334.50 | 1 | 334.50 | 65.22 | <0.0001 | |
| AB | 6.81 | 1 | 6.81 | 1.33 | 0.2870 | |
| Residual | 35.90 | 7 | 5.13 | |||
| Lack of Fit | 34.46 | 3 | 11.49 | 31.87 | 0.0030 | |
| Pure Error | 1.44 | 4 | 0.36 | |||
| Cor Total | 2686.53 | 12 | ||||
| Std. Dev: 2.26, R2: 0.9866, Mean: 33.67; Adj R2: 0.9771, C.V: 6.73; Pred R2: 0.9079; Adeq Precision: 34.585 | ||||||
| Color Removal (%) | Source | Sum of Squares | DF | Mean Square | F Value | Prob > F |
| Model | 3003.96 | 5 | 600.79 | 58.23 | <0.0001 | |
| A | 2167.80 | 1 | 2167.80 | 210.10 | <0.0001 | |
| B | 39.36 | 1 | 39.36 | 3.82 | 0.0917 | |
| A2 | 207.87 | 1 | 207.87 | 20.15 | 0.0028 | |
| B2 | 607.43 | 1 | 607.43 | 58.87 | 0.0001 | |
| AB | 61.68 | 1 | 61.68 | 5.98 | 0.0444 | |
| Residual | 72.22 | 7 | 10.32 | |||
| Lack of Fit | 50.44 | 3 | 16.81 | 3.09 | 0.1523 | |
| Pure Error | 21.78 | 4 | 5.44 | |||
| Cor Total | 3076.18 | 12 | ||||
| Std. Dev.: 3.21, R2: 0.9765, Mean: 71.97, Adj R2:0.9598, C.V.:4.46 Pred R2:0.8723, Adeq Precision: 21.336 | ||||||
| Source | Sum of Squares | DF | Mean Square | F Value | Prob > F | |
| NH3–N Removal (%) | Model | 529.27 | 5 | 105.85 | 20.75 | 0.0005 |
| A | 114.12 | 1 | 114.12 | 22.37 | 0.0021 | |
| B | 28.75 | 1 | 28.75 | 5.64 | 0.0493 | |
| A2 | 78.35 | 1 | 78.35 | 15.36 | 0.0058 | |
| B2 | 260.56 | 1 | 260.56 | 51.08 | 0.0002 | |
| AB | 3.71 | 1 | 3.71 | 0.73 | 0.4220 | |
| Residual | 35.71 | 7 | 5.10 | |||
| Lack of Fit | 29.08 | 3 | 9.69 | 5.85 | 0.0604 | |
| Pure Error | 6.62 | 4 | 1.66 | |||
| Cor Total | 564.98 | 12 | ||||
| Std. Dev.: 2.26, R2: 0.9368: Mean: 68.13, Adj R2: 0.8917, C.V.: 3.32: Pred R2: 0.6156, Adeq Precision: 17.580 | ||||||
| TSS Removal (%) | Source | Sum of Squares | DF | Mean Square | F Value | Prob > F |
| Model | 631.55 | 5 | 126.31 | 13.02 | 0.0020 | |
| A | 115.80 | 1 | 115.80 | 11.94 | 0.0106 | |
| B | 42.23 | 1 | 42.23 | 4.35 | 0.0754 | |
| A2 | 2.88 | 1 | 2.88 | 0.30 | 0.6030 | |
| B2 | 405.95 | 1 | 405.95 | 41.84 | 0.0003 | |
| AB | 66.69 | 1 | 66.69 | 6.87 | 0.0343 | |
| Residual | 67.91 | 7 | 9.70 | |||
| Lack of Fit | 53.14 | 3 | 17.71 | 4.80 | 0.0820 | |
| Pure Error | 14.77 | 4 | 3.69 | |||
| Cor Total | 699.46 | 12 | ||||
| Std. Dev.: 3.11, R2: 0.9029, Mean: 51.45, Adj R2: 0.8336, C.V.: 6.05, Pred R2: 0.4267, Adeq Precision:10.690 | ||||||
A: pH B: Tannin dosages.