Lelisa Regea Mengistu - Jimma Institute of Technology, Faculty of Civil and Environmental Engineering, Jimma University, P.O. Box. ۳۷۸, Jimma, Ethiopia
Chali Dereje Kitila - Corresponding author: Jimma Institute of Technology, Faculty of Civil and Environmental Engineering, Jimma University, P.O. Box. ۳۷۸, Jimma, Ethiopia

Background: Electrocoagulation is becoming a promising eco-friendly wastewater treatment technique. It is a low-cost wastewater treatment method suitably applied for various wastewater effluent characteristics. Nevertheless, there are different kinds of electrocoagulation; comparison among them in terms of nutrient removal is investigated in the present research. This study analyzed nitrate (NO۳-) and phosphate (PO۴۳-) removal potential of the sono-alternative and direct-current electrocoagulation process. Methods: Batch reactor and sono-direct current (SDC)/sono-alternative current (SAC) electrocoagulation cell were employed to investigate NO۳- and PO۴۳- removal efficiency from domestic effluents. The data gathered from laboratory experiments were analyzed using response surface methodology (RSM). ANOVA was used to examine the interaction effects of diverse parameters in terms of NO۳_ and PO۴۳- removal from domestic wastewater effluents. Results: At extreme experimental conditions, the percentage of NO۳- and PO۴۳- removal attained with sono-direct current electrocoagulation (SDCE) and sono-alternative current electrocoagulation (SACE) were ۹۶.۵%, ۹۶.۲% and ۹۶.۸%, ۹۶.۵, respectively. The SACE was more successful in eliminating NO۳- and PO۴۳- than the SDCE process. The appearance of resistant oxide coating on the cathode and the appearance of corrosion on the anode due to oxidation processes in the case of SDCE were identified as principal factors highly affecting NO۳- and PO۴۳- removal efficiency. Conclusion: With optimum process efficiency, experimental findings show that the SACE process is more capable of NO۳- and PO۴۳- removal than the SDCE process.

Electrocoagulation, Nitrates, Phosphates, Wastewater, Water purification