Abstract
The local lime has been used as a coagulant and a coagulant aid with ferrous sulfate in turbidity removal for deferent level of initial synthetic turbidity (25,100,500) ntu. The study revealed that the lime can effectively be used alone as a coagulant with medium and high initial turbidity levels (100and500) ntu, And it revealed a better result when it used as a coagulant aid with ferrous sulfate at low initial turbidity limit 25ntu with a dose of 20mg/l with 7.5mg/l of ferrous sulfate to get a removal of 93% of turbidity.
Regression analysis has been done and a mathematical model determined for the variables included in the study, and it found that the most important variable affect to turbidity removal is the initial turbidity followed by settling time then ferrous sulfate dose then lime dose.