Afshin Takdastan - Associate Professor, department of environmental health, and Environmental technologies research center ,Ahvaz Jundi Shapur university of medical sciences, Ahvaz,Iran
Azadeh Mirzaei - Department of environmental health, Ahvaz Jundi Shapur university of medical sciences, Ahvaz, Iran
Nadali Alavi - Associate Professor, department of environmental health, and Environmental technologies researchcenter ,Ahvaz Jundi Shapur university of medical sciences, Ahvaz,Iran

PAC hydrolyses with great ease as compared to alum, emitting polyhydroxides with long molecularchains & greater electrical charge in the solution, thus contributing to maximize the physical action of theflocculation. Better coagulation is obtainedwith PAC as compared to alum at medium & high turbidity waters.Floc formation with PAC is quite rapid. The sludge produced by PAC is more compact than that produced byalum.The study was carried out at Water Treatment Plant. in order to determine the optimum conditions of PAC performance in turbidity, coliform bacteria and heterotrophic bacteria removal, tests were performed based on variables such as coagulant dose (3,5,8,10,15,20,30,40,50 mg/Lit), pH(5.5, 6, 6.5, 7, 7.5, 8) and turbidity between 33-100 NTU. The residual turbidity and microbial parameters of samples were measured and coagulant performance in turbidity and microbial parameter removal were determined. The results showed that the most optimal conditions for turbidity removal and microbial parameters efficiency by PAC were pH=8, flash mixing =120 rpm and the optimal doses of PAC were obtained as 10 and 30 ppm. The turbidity, total coliform, fecal coliform and Heterotrophic bacteria removal efficiency under optimum condition of PAC application for dose 10ppm were, respectively, 96.59, 90, 82.75, 84.17% while turbidity, total coliform, fecal coliform and heterotrophic bacteria removal efficiency under optimum condition of PAC dose of 30ppm was 99 , 94.65 , 88.94 , 90.47%, respectively.

Karoon river, AhvazWater treatment,PolyAluminumChloride,Turbidity,Coliform