Phosphate and nitrogen removal by iron produced in electrocoagulation reactor

Abstract

In this study, concentrated iron solution generated by electrocoagulation (EC) process was used for the removal of nutrients from human urine (yellow water). Yellow water was prepared synthetically with major components: nitrogen and phosphorus. As a result of the pH adjustment, nitrogen and phosphorus, which are present in urine, react with electrochemically generated iron solution and then accumulate in the sludge by precipitation. All experiments were done under different pH values for the evaluation of this novel EC nutrient removal process. The effect of the EC treatment on the removal of nutrients was followed by total nitrogen and phosphate measurements and Fourier transform infrared spectroscopy (FTIR). The effects of treatment parameters (pH, iron/phosphate, iron/nitrogen, and iron/nutrient ratios) on the performance of the EC treatment were also examined for the evaluation of applicability of this novel EC method for the treatment of yellow waters. The results show that the pH increase improved phosphate removal efficiencies at definite molar nutrient ratios. The phosphate removal efficiency was approximately 98% at pH 8 for 1:1 of iron/nutrient molar ratio and on the other hand, nitrogen removal was only 21% at pH 8 for 4:1 of iron/urea molar ratio. Total organic carbon (TOC) removal efficiency was reached to 26% of the process. FTIR adsorption spectra were discussed for the sludge obtained.