Application of Polyaluminum Chloride (PACl) in turbidity removal of Tehran drinking water- Case study: Jalalieh water treatment plant

The main aims of this study were to compare the effectiveness of Polyaluminum Chloride (PACl) and Ferric Chloride, to optimization the coagulation/flocculation process, to investigate the effect of adding bentonite (as a coagulant aid) and to compare the residual Aluminum after adding PACl and Alum. Samples were collected from influent of Jalalieh water treatment plant, Tehran, Iran. In the first phase, the effectiveness of PACl and Ferric Chloride was compared. In this phase, the optimum coagulant dosages were 40 and 35 mg/L for Ferric Chloride and PACl, respectively. In the second phase, with adding 20 mg/L of bentonite, the optimum coagulant dosages were reduced to 25 and 15 mg/L for Ferric Chloride and PACl, respectively. The results of third phase of this study showed that PACl leaves less  residual Aluminum  than Alum.