Background & Objectives: Phosphorus as a main nutrient for plants is responsible for eutrophication of surface water. In this research, efficiency of orthophosphate removal through chemical precipitation process using lime and Bentonite clay was investigated in west wastewater treatment plant of Ahvaz. Methods: This bench scale study was conducted on influent of secondary clarifier. The effect of pH and coagulant dose on orthophosphate removal efficiency was investigated using jar test. Results: Orthophosphate removal efficiency increases by increasing coagulant dose and pH. Comparing with bentonit, lime displayed higher efficiency in orthophosphate removal from wastewater at normal pH range. Lime reduced orthophosphate concentration to 0.404 mg/l at a dose of 80 mg/l and pH=7. Conclusion: Comparing with bentonit, lime may be used as appropriate and economic coagulant to remove orthophosphate from effluent of wastewater treatment plant, since it has high efficiency and there is also no need to modify PH to an optimum level, resulting in reduced chemical cost.