| Parameters | Vary Factors | ||
| PCA1 | PCA2 | PCA3 | |
| Flow | 0.952 | 0.146 | −0.093 |
| MLSS | 0.078 | 0.911 | −0.006 |
| pH | −0.082 | 0.009 | 0.981 |
| Temp | 0.226 | 0.691 | −0.012 |
| TSSi | 0.788 | 0.264 | −0.362 |
| BODi | 0.866 | 0.360 | −0.035 |
| CODi | 0.793 | 0.413 | 0.096 |
| TSSe | 0.943 | 0.193 | −0.058 |
| BODe | 0.910 | −0.158 | −0.099 |
| CODe | 0.809 | 0.187 | 0.007 |