Coagulation performance and residual aluminum specitation of Al2(SO4)3 and polyaluminum chloride (PAC) in Yellow River water treatment

The effect of pH and coagulant dosage on the coagulation performance of aluminum sulphate and polyaluminum chloride (PAC) with respect to the treatment of Yellow River water was investigated in this paper The separation and measurement of residual aluminum (Al) speciation were also conducted The results indicated that PAC showed superior coagulation performance compared to that of Al-2(SO4)(3) in most cases during the Yellow River water treatment At a dosage of 15 mg/L as Al2O3 PAC achieved an optimum removal efficiency of turbidity UV254 and DOC of 96 3 57 1 327% respectively and Al-2(SO4)(3) also achieved an optimum removal efficiency of turbidity UV254 and DOC of 94 5 53 5348% respectively Foi PAC and Al-2(SO4)(3) the optimum pH during the treatment of Yellow River water could be determined at 60 Different residual Al speciation exhibited different trends with dosage and pH variation For the two coagulants studied no matter the dosage or pH the majority of residual total Al existed most in the form of total dissolved Al among which dissolved organically bound Al was the predominant speciation Most of the dissolved monomeric Al in the effluent was dissolved inorganically bound monomeric Al PAC showed lower concentiation for the several kinds of residual aluminum species except the dissolved organically bound Al and PAC could effectively reduce the concentration of dissolved monomeric Al (C) 2010 Elsevier B V All rights reserved