Table 5: Variables selected for residual aluminium using multiple linear regression (MLR).

RoundVariablesCorrelation coefficient (C)

1Water temperature0.72
2Aluminium dose/raw water KMnO40.79
3Silicates in raw water0.81
4pH of raw water0.81
5Hardness of raw water0.82
6Flocculation pH0.82
7Conductivity of raw water0.82
8Total intake of water0.82
9Surface level of Lake Humaljärvi0.82
10Colour of raw water0.82