Effect of coagulation and flocculation process

Coagulation and flocculation are the basis of water treatment, for the separation of solid-liquid mixtures, as well as a means to reduce turbidity, and in the present investigation, the effect of the applied speed and dose of aluminum sulfate Al2 (SO4)3, as well as that exerted by the ferric chloride FeCl3-flocculant, was evaluated. To obtain the experimental data, a 'Jar Test' equipment was used, carrying out tests at 06 levels of applied dose (1, 2, 3, 4, 5 and 6 mL), and at 05 levels of agitation speed (100, 150, 200, 250 and 300 r.p.m.). The results report that the best conditions, with Aluminum Sulfate, were achieved with a dose of 120 mg/L and at a speed of 100 r.p.m. of fast mixing and 25 r.p.m. of slow mixing, decreasing the initial color from 213 UPC to 10 UPC, an initial turbidity from 66.6 to 1.1 UNT, an initial concentration of Fe (II) from 1.37 to 0.05 mg/L and a decrease in pH from 6.6 to 4.20.