Investigation of coagulation and flocculation conditions for DAF in drinking water treatment for public source containing moderated color and low turbidity

This paper presents some lab scale results from an investigation such the main aim was to obtain coagulation and flocculation conditions by treating water containing medium color e low turbidity where systems that apply sedimentation units usually have low efficiency causing overload on the filtration following units. For this propose the following parameters were evaluated: i)coagulant type; ii) dosages, mixture e recirculation conditions (p) e iii) flocculation conditions. The aluminum sulfate in 25 mg.L-1 (2,25mgAl+3.L-1) in pH value around 6,25 and recirculation of 8% v/v (8,4g of air.m-3 of raw water) were pointed as the bests conditions. The best’s flocculation conditions were: 50 and 90 s-1 for 8 minutes.