Deep Treatment of Ammonia Nitrogen Tannery Wastewater by an Electro-Fenton System

摘要

The effect of an Electro-Fenton system on the deep treatment of ammonia nitrogen (NH3-N) and corresponding removal rate was investigated in this article. By using simulated ammonia nitrogen wastewater, it included a Cl- concentration of 3000 mg/L, SO42- concentration of 100 mg/L according to conventional leather wastewater conditions. Furthermore, Cl- and SO42- can be used as supporting electrolyte. After pretreatment, the ammonia nitrogen concentration kept about 100 mg/L. The optimal treatment conditions of Electro-Fenton system were obtained throughout single factors experiments. The current density was 150 A/m(2), the reaction time was 30 min, the plate spacing distance was 40 mm, and the reaction temperature was adjusted to 40 degrees C. After flocculation treatment of leather wastewater, the ammonia nitrogen concentration was 142.11 mg/L, and the tanning wastewater was further treated with an Electro-Fenton system. The final ammonia nitrogen concentration was 11.23 mg/L, which meets the first-level wastewater discharge standard. The removal rate was 92.10%, which indicated that the Electro-Fenton system is one kind of clean, feasible and sustainable treatment method for the deep treatment of ammonia nitrogen in tannery wastewater.