| n˚ exp | Factors | Experimental Phosphate removal Yexp (%) | Theorical phosphate removal Ycalc (%) | Residues (%) | Coefficient of variation (%) | |||
| Coded variables | Reals variables | |||||||
| X1 | X2 | U1 (˚C) | U2 (H) | |||||
| 1 | −1 | −1 | 58 | 9 | 39.97 | 38.66 | 1.31 | 3.28 |
| 2 | +1 | −1 | 93 | 9 | 40.8 | 42.06 | −1.26 | 3.09 |
| 3 | −1 | +1 | 58 | 15 | 5551 | 54.1 | 1.41 | 2.54 |
| 4 | +1 | +1 | 93 | 15 | 69.05 | 72.22 | −3.17 | 4.59 |
| 5 | −1.414 | 0 | 50 | 12 | 41.32 | 42.83 | −1.51 | 3.65 |
| 6 | +1.414 | 0 | 100 | 12 | 67.25 | 64.08 | 3.17 | 4.71 |
| 7 | 0 | −1.414 | 75 | 8 | 38.75 | 37.25 | 1.5 | 3.87 |
| 8 | 0 | +1.414 | 75 | 16 | 69.45 | 68.08 | 1.37 | 1.97 |
| 9 | 0 | 0 | 75 | 12 | 43.75 | 43.12 | 0.63 | 1.44 |
| 10 | 0 | 0 | 75 | 12 | 42.97 | 43.12 | −0.15 | 0.35 |
| 11 | 0 | 0 | 75 | 12 | 43.38 | 43.12 | 0.26 | 0.60 |
| 12 | 0 | 0 | 75 | 12 | 41.75 | 43.12 | −1.37 | 3.28 |
| 13 | 0 | 0 | 75 | 12 | 43.75 | 43.12 | 0.63 | 1.44 |