| Experiment | Factor A | Factor B | Factor C | Factor D | COD removal |
| Number | % | ||||
| 1 | 1 | 1 | 1 | 1 | 52.5 |
| 2 | 1 | 2 | 2 | 2 | 82.2 |
| 3 | 1 | 3 | 3 | 3 | 18.2 |
| 4 | 2 | 1 | 2 | 3 | 79.1 |
| 5 | 2 | 2 | 3 | 1 | 69.0 |
| 6 | 2 | 3 | 1 | 2 | 62.1 |
| 7 | 3 | 1 | 3 | 2 | 83.8 |
| 8 | 3 | 2 | 1 | 3 | 82.7 |
| 9 | 3 | 3 | 2 | 1 | 42.9 |
| K1 | 152.9 | 215.4 | 197.3 | 164.4 |
|
| K2 | 210.2 | 233.9 | 204.2 | 228.1 |
|
| K3 | 209.4 | 123.2 | 171 | 180 |
|
| k1 | 51 | 71.8 | 65.8 | 54.8 |
|
| k2 | 70.1 | 78 | 68.1 | 76 |
|
| k3 | 69.8 | 41.1 | 57 | 60 |
|
| R | 19.1 | 36.9 | 11.1 | 21.2 |
|