Table 3: Variables selected for turbidity using multiple linear regression.

RoundVariablesCorrelation coefficient (C)

1Aluminium dose0.55
2Intake from the pikkala reservoir0.62
3Turbidity of raw water0.66
4Proportion of Lake Humaljärvi/Pikkala reservoir water intake0.70
5Colour of raw water0.71
6KMnO4 of raw water0.71
7Flocculation pH0.71
8Water temperature0.71
9Aluminium dose/raw water KMnO40.71
10Silicates in raw water0.71