removal of phosphorus, organic matter and suspended solids by poly aluminum chloride from municipal wastewater (case study: ahvaz west wastewater treatment plant)

phosphorus is an important nutrient for plant and microorganisms growth, thus has an important role in creating eutrophication of surface waters. the present study has investigated poly aluminum chloride efficiency on orthophosphate removal by coagulation and chemical precipitation process in municipal wastewater in west wastewater treatment plant. this bench scale study was performed on influent wastewater to the primary and secondary clarifier and the effluent of the secondary clarifier in west wastewater treatment plant. by using a jar test, the optimum ph and dose of poly aluminum chloride in orthophosphate removal was determined. the results showed that poly aluminum chloride in ph =7 , and in doses between 20 , 30 and 30 {{include|equation|eq_idp542144}} decreases orthophosphate concentration to 0.51 , 0.705 and 0.43 {{include|equation|eq_idp548608}} respectively and the influent point to the primary clarifier , with the lowest consume of coagulant dose and consequently the low cost of this process in treatment plant , has been selected as the optimum sampling point. as the results show, the efficient removal of orthophosphate, organic material and suspended material using poly aluminum chloride are desirable, and orthophosphate concentration in effluents decreased to lower than 1{{include|equation|eq_idp564112}}.