Investigation of Interaction of Effecting Factors in Phosphate and Nitrate Removal from Municipal Wastewater by Electrocoagulation Process with RSM Approach

One of the environmental problems of wastewater is the presence of micro and macro nutrients, the most important of which is phosphorus and nitrate. Hence, in this study removal of phosphate and nitrate from aqueous solution was conducted using electrocoagulation (EC) processes with Al electrodes. In the present study, an electrocoagulation reactor was used in a laboratory scale with a volume of approximately 1200 ml equipped with 3 Al-electrode in a size of 5 × 12 cm to remove phosphate and nitrate. The effects of operating parameters such as applied voltage, initial pH of the solution, value of FeCl2 and reaction times were evaluated. The effect of pH and FeCl2 parameters in inlet and facultative ponds were also studied. Also, pH changes in the oxidation process were investigated. Finally, it can be said that phosphate was completely eliminated in facultative and outflow ponds, but due to the low initial concentration of phosphate in the outlet, less voltage (10 V), less time (about 3 minutes), low FeCl2 dosage (0.2 mg/l) and original pH of the solution were applied compared to the facultative pond., 100 % of nitrate in optimum condition (pH =5.5, applied voltage = 25 V, FeCl2 = 0.65 mg/l, time = 11.50 min) in output pond has been removed. In EC process the electrocoagulation process using aluminum electrode, as well as it's relatively low cost and simplicity, has a good effect on phosphorus and nitrate removal compared to other methods.