Optimization of phosphate removal from wastewater by electrocoagulation with aluminum plate electrodes

The Taguchi method was used to determine the optimum conditions for the phosphate removal from wastewater by electrocoagulation with aluminum plate electrodes. The experimental parameters investigated were initial phosphate concentration, initial pH of the wastewater, supporting electrolyte concentration, supporting electrolyte type and current density. The ranges of experimental parameters were between 50 and 500 mg/L (as PO 4–P), 4–7 for initial pH, 0–10 mM, NaCl, NaNO 3, Na 2SO 4 and CaCl 2 and 0.25–1.00 mA/cm 2 mm for initial phosphate concentration, initial pH of the wastewater, supporting electrolyte concentration, supporting electrolyte type and current density, respectively. Reaction period was kept constant in 25 min for statistical analysis. The optimum conditions for these parameters were found to be 50 mg/L, 4, 5 mM, NaCl and 1.00 mA/cm 2, respectively. Under these conditions, the predicted and experimental removal efficiency of phosphate from wastewater by electrocoagulation with aluminum plate electrodes were 99.9 and 100.0%, respectively. A statistical analysis of variance (ANOVA) was performed to see whether the process parameters were statistically significant or not. According to the F-test results, it can be concluded that the degrees of the influences of parameters on the removal efficiency is initial phosphate concentration, current density and initial pH of the solution.